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WO2024032237A1 - 预发泡材料及其制备方法和应用 - Google Patents

预发泡材料及其制备方法和应用 Download PDF

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Publication number
WO2024032237A1
WO2024032237A1 PCT/CN2023/104368 CN2023104368W WO2024032237A1 WO 2024032237 A1 WO2024032237 A1 WO 2024032237A1 CN 2023104368 W CN2023104368 W CN 2023104368W WO 2024032237 A1 WO2024032237 A1 WO 2024032237A1
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WO
WIPO (PCT)
Prior art keywords
foaming
foamed material
foamed
modified polymer
crystalline thermoplastic
Prior art date
Application number
PCT/CN2023/104368
Other languages
English (en)
French (fr)
Inventor
胡新利
赵玲
陈弋翀
赵艳菲
胡冬冬
王铮
李程
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Publication of WO2024032237A1 publication Critical patent/WO2024032237A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F257/00—Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00
    • C08F257/02—Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00 on to polymers of styrene or alkyl-substituted styrenes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B29C44/3415—Heating or cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B29C44/3442—Mixing, kneading or conveying the foamable material
    • B29C44/3446—Feeding the blowing agent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B29C44/35—Component parts; Details or accessories
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/046—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of foam
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B32B15/082—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising vinyl resins; comprising acrylic resins
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    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/20—Layered products comprising a layer of metal comprising aluminium or copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
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    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/18—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer of foamed material
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • C08F212/02—Monomers containing only one unsaturated aliphatic radical
    • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
    • C08F212/06—Hydrocarbons
    • C08F212/08—Styrene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F222/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
    • C08F222/04—Anhydrides, e.g. cyclic anhydrides
    • C08F222/06—Maleic anhydride
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F222/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
    • C08F222/10—Esters
    • C08F222/12—Esters of phenols or saturated alcohols
    • C08F222/20—Esters containing oxygen in addition to the carboxy oxygen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F259/00—Macromolecular compounds obtained by polymerising monomers on to polymers of halogen containing monomers as defined in group C08F14/00
    • C08F259/08—Macromolecular compounds obtained by polymerising monomers on to polymers of halogen containing monomers as defined in group C08F14/00 on to polymers containing fluorine
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/122—Hydrogen, oxygen, CO2, nitrogen or noble gases
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B2266/00—Composition of foam
    • B32B2266/02—Organic
    • B32B2266/0214—Materials belonging to B32B27/00
    • B32B2266/0221—Vinyl resin
    • B32B2266/0228—Aromatic vinyl resin, e.g. styrenic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
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    • B32B2266/00—Composition of foam
    • B32B2266/08—Closed cell foam
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    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2266/00—Composition of foam
    • B32B2266/10—Composition of foam characterised by the foam pores
    • B32B2266/104—Micropores, i.e. with average diameter in the range from 0.1 µm to 0.1 mm
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/10—Properties of the layers or laminate having particular acoustical properties
    • B32B2307/102—Insulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B2307/30—Properties of the layers or laminate having particular thermal properties
    • B32B2307/304—Insulating
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    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
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    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B32B2457/08—PCBs, i.e. printed circuit boards
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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    • C08J2203/06—CO2, N2 or noble gases
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    • C08J2351/00—Characterised by the use of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers

Definitions

  • the present application relates to the technical field of foam materials, and specifically relates to a pre-foam material and its preparation method and application.
  • PCB Printed Circuit Board
  • Syndiotactic polystyrene is considered to be one of the potential dielectric layer materials for high-frequency PCBs because of its high melting point, low density, low water absorption, and excellent high-frequency dielectric properties.
  • the sPS material is a crystalline material with a narrow melting range, making it difficult to obtain a lightweight dielectric layer through supercritical foaming.
  • the sPS foaming material directly produced by the supercritical foaming method is prone to delamination and foaming. Most of the holes are open and have high water absorption, which cannot meet the requirements of PCB boards. Therefore, it is necessary to provide a foam material with low water absorption and good dielectric properties.
  • embodiments of the present application provide a foaming material with low dielectric constant, dielectric loss, and low water absorption, as well as its preparation raw materials, applications, and the like.
  • the first aspect of the embodiment of the present application provides a pre-foamed material
  • the pre-foamed material includes a modified polymer
  • the modified polymer has a first structural unit derived from an unsaturated monomer
  • the molecular chain end of the modified polymer is capped with a crystalline thermoplastic resin.
  • the modified polymer in the above-mentioned pre-foamed material is a new polymer composed of structural units derived from unsaturated monomers and crystalline thermoplastic resin.
  • the three-dimensional structure of the modified polymer is relatively low in regularity, so its melt The range is relatively wide, so the foaming temperature does not need to be controlled in a particularly narrow window when using this pre-foamed material for foaming; there is no obvious difference in the degree of arrangement of the modified polymer in the surface layer and inner layer of the pre-foamed material.
  • the foamed material obtained by foaming the pre-foamed material is not prone to delamination; in addition, compared with simple crystalline thermoplastic resin, the presence of the modified polymer increases the melt strength of the pre-foamed material. , which can ensure that most of the cells of the foamed material are closed cells and the water absorption rate is low.
  • the crystalline thermoplastic resin includes syndiotactic polystyrene, polytetrafluoroethylene, polyvinylidene fluoride, perfluoroalkoxy vinyl ether polymer, polyphenylene sulfide, polyether ether ketone, One or more liquid crystal polymers.
  • These crystalline thermoplastic resins usually have good heat resistance and low dielectric properties, and are more suitable for use as foam raw materials for making PCB boards.
  • the unsaturated monomer includes one or more of styrene, maleic anhydride, pentaerythritol triacrylate, methacrylate, glycidyl methacrylate, and ethyl acrylate.
  • Structural units derived from these monomers help to improve the melt strength of the above-mentioned modified polymers, which can effectively alleviate the problems of delamination and mostly open cells in the foamed materials of the above-mentioned pre-foamed materials, and at the same time improve the The dielectric properties of the modified polymer have little effect.
  • the modified polymer has a structural formula represented by formula (I):
  • M 1 represents the first structural unit derived from an unsaturated monomer
  • m represents the degree of polymerization of M 1
  • P 1 is independently selected from crystalline thermoplastic resins.
  • the pre-foamed material is obtained by reacting the following raw materials in parts by weight: 100 parts of crystalline thermoplastic resin matrix, 0.1-5 parts of unsaturated monomer, and 0.1-5 parts of initiator.
  • the smaller amount of initiator and unsaturated monomer helps to ensure a higher yield of the above-mentioned modified polymer, while the by-product - unsaturated monomer polymer is less.
  • the initiator includes dicumyl peroxide, di(tert-butylcumylperoxy)benzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy) )Hexane, 2-(tert-butylperoxyisopropyl)benzene, butanone peroxide, dibenzoyl peroxide, dodecanoyl peroxide Or multiple.
  • the initiator can cause the molecular chain of the crystalline thermoplastic resin to generate free radicals as reaction sites to initiate the polymerization reaction of unsaturated monomers, thereby producing a modified polymer with the above structure.
  • the pre-foamed material also contains antioxidants.
  • the mass of the antioxidant is 0.09wt%-1wt% of the mass of the modified polymer. The addition of an appropriate amount of antioxidants can help improve the stability of pre-foamed materials during the manufacturing/use process.
  • the pre-foamed material has a melting range above 15°C and a melting point above 270°C at a heating rate of 10°C/minute based on differential scanning calorimetry. This helps reduce the difficulty of precise control of the foaming temperature of the pre-foamed material during the foaming process and ensures good heat resistance of the resulting foamed material.
  • the second aspect of the embodiment of the present application provides a foaming material, which is obtained by foaming the pre-foamed material described in the first aspect of the embodiment of the present application.
  • the foaming is particularly supercritical foaming.
  • most of the cells in the foam material are closed cells. Closed cells help ensure that the foam material has excellent water absorption resistance.
  • the water absorption rate of the foamed material after being placed in water for 24 hours at a temperature of 23°C and a relative humidity of 50% is less than 1%. Lower water absorption is beneficial to extending the service life of foam materials.
  • the average cell size of the foam material is in the range of 5-100 ⁇ m.
  • the density of the foam material is below 1 g/cm 3 .
  • Low-density foam materials are conducive to ensuring the lightweight of devices using them.
  • the dielectric constant of the foam material under electromagnetic waves with a frequency of 10 GHz is measured to be below 2.0, and the dielectric loss is below 0.0015.
  • the foam material has excellent dielectric properties and is suitable for making high-frequency and high-speed PCB boards.
  • the third aspect of the embodiments of the present application provides a method for preparing pre-foamed materials, which includes the following steps:
  • the crystalline thermoplastic resin and the initiator are melt-blended, and then unsaturated monomers are added for melt-blending to prepare a pre-foamed material containing a modified polymer; wherein, under the action of the initiator, the The crystalline thermoplastic resin can terminate the end of the polymer obtained by the polymerization reaction of the unsaturated monomer to obtain a modified polymer.
  • the above-mentioned specific feeding sequence can ensure a higher yield of the above-mentioned modified polymer and a wider melting range of the pre-foamed material.
  • the weight part of the initiator is 0.1-5 parts, and the weight part of the unsaturated monomer is 0.1-5 parts.
  • the addition amount of initiator and unsaturated monomer is lower than that of crystalline thermoplastic resin, which helps ensure a higher yield of modified polymer in the pre-foamed material and fewer by-products.
  • the fourth aspect of the embodiments of the present application provides a foaming device for preparing foaming materials, including:
  • Foaming container used to place products to be foamed, which are the pre-foamed material described in the first aspect of the embodiment of the present application or a molded product of the pre-foamed material;
  • a temperature control system for heating the foaming container to reach a preset temperature
  • a high-pressure conveying system used to convey supercritical foaming agent into the foaming container so that the pressure of the foaming container reaches a preset pressure
  • a pressure relief system used to release the pressure in the foaming container after the supercritical foaming agent impregnates the product to be foamed and is saturated, so that the product to be foamed is foamed to form the foam. Material.
  • the fifth aspect of the embodiment of the present application provides a raw material for foaming, including component A and component B, wherein the component A includes a crystalline thermoplastic resin and an initiator, and the component B includes an unsaturated monomer.
  • the crystalline thermoplastic resin can end-block the polymer obtained by polymerizing the unsaturated monomer. end.
  • component A and component B are placed separately.
  • component A can be converted into a molten state first, and then component B is added, and through melting and blending reaction, A pre-foamed material containing the above modified polymer is prepared.
  • the sixth aspect of the embodiments of the present application provides the application of the pre-foamed material described in the first aspect of the embodiments of the present application and the foaming raw material described in the fifth aspect of the embodiments of the present application in preparing foaming materials.
  • the foamed material may also be called foamed material.
  • the seventh aspect of the embodiments of the present application provides the pre-foamed material described in the first aspect of the embodiments of the present application, the foaming material described in the second aspect of the embodiments of the present application, and the foaming material described in the fifth aspect of the embodiments of the present application.
  • the foaming method can be used in the preparation of printed circuit boards, cushioning materials, shock-absorbing materials, thermal insulation materials, sound-absorbing materials, etc. That is, printed circuit boards, cushioning materials, shock-absorbing materials, heat-insulating materials, sound-absorbing materials, etc. may include foaming materials.
  • the eighth aspect of the embodiment of the present application provides a laminate.
  • the laminate includes a dielectric layer sheet and a metal foil located on the surface of the dielectric layer sheet, wherein the dielectric layer sheet includes the second aspect of the embodiment of the present application.
  • the dielectric layer sheet in the laminate has lower dielectric properties, lower water absorption and lighter density, and is suitable for making lightweight, high-frequency and high-speed printed circuit boards.
  • the ninth aspect of the embodiment of the present application provides a printed circuit board, which includes at least one laminate as described in the eighth aspect of the embodiment of the present application.
  • the tenth aspect of the embodiment of the present application provides an electronic component, which includes the printed circuit board described in the ninth aspect of the embodiment of the present application.
  • An eleventh aspect of the embodiment of the present application provides an electronic device.
  • the electronic device includes the electronic component of the tenth aspect of the embodiment of the present application or the printed circuit board described in the ninth aspect of the embodiment of the present application.
  • the performance of electronic equipment can be improved.
  • the embodiments of the present application also provide a modified polymer, the modified polymer has the structural formula shown in formula (I):
  • M 1 represents the first structural unit derived from an unsaturated monomer
  • m represents the degree of polymerization of M 1
  • P 1 is independently selected from crystalline thermoplastic resins.
  • the modified polymer has low stereoregularity, wide melting range, and high melt strength.
  • the embodiments of this application also provide the application of the above-mentioned modified polymer in preparing foaming materials, plastic sealing materials, adhesives, and resin compositions.
  • Figure 1 is a schematic structural diagram of a laminate in a PCB board provided by an embodiment of the present application.
  • Figure 2 is a schematic diagram of a foaming device used to prepare foaming materials provided in the embodiment of the present application.
  • Figure 3 is a scanning electron microscope photograph of the foam material obtained in Example 1 of the present application.
  • Figure 4 is a scanning electron microscope photograph of the foam material obtained in Example 2 of the present application.
  • Figure 5 is a scanning electron microscope photograph of the foam material obtained in Comparative Example 1.
  • the laminate 10 generally includes a dielectric layer sheet 11 and a metal foil 12 located on at least one side surface of the dielectric layer sheet 11 .
  • the laminate 10 is generally a copper clad laminate (Copper Clad Laminate, abbreviated as CCL).
  • CCL Copper Clad Laminate
  • the CCL may include a dielectric layer sheet 11 and copper foils formed on opposite sides of the dielectric layer sheet 11 .
  • the signal transmission in the PCB board is carried out in the metal foil 12, and the dielectric layer sheet 11 between the metal foils 12 plays the role of isolating the metal foil 12. The lower the dielectric constant of the dielectric layer sheet 11, the better the dielectric layer sheet 11 will be.
  • the embodiment of the present application provides a pre-foamed material, which is suitable for preparing the above-mentioned dielectric layer sheet 11 in the PCB board through a foaming method, and gives the foamed material-dielectric layer sheet 11 Good dielectric properties as well as lighter density, lower water absorption, etc.
  • embodiments of the present application provide a pre-foamed material, which includes a modified polymer, wherein the modified polymer has a first structural unit derived from an unsaturated monomer, so The molecular chain ends of the modified polymer are capped with crystalline thermoplastic resin.
  • Crystalline thermoplastic resin generally has a melting point, and the molecules are arranged more neatly. The more neatly arranged the molecules are, the narrower the melting range of the crystalline thermoplastic resin is, and the higher the degree of precision control over the foaming temperature when foaming using it.
  • unmodified crystalline thermoplastic resin is used to manufacture pre-foamed materials, such as during injection molding, due to the highly regular three-dimensional structure of the crystalline thermoplastic resin, the polymers on the surface layer are easily oriented and arranged along the mold. This makes the surface and inner structures of the obtained pre-foamed material (specifically, the particles used for foaming) inconsistent.
  • the surface layer structure is denser, which makes the supercritical gas dissolved into the surface layer when using pre-foamed materials for supercritical foaming. If there is less, more supercritical gas will be dissolved into the inner layer. While rapid pressure relief will produce cells, the resulting foamed material will also be prone to stratification. In addition, the melt strength of crystalline thermoplastic resin is low and cannot support the growth of cells. Most of the cells obtained by foaming are open cells, and the water absorption rate of the foamed material is low.
  • the modified polymer provided in this application is a new polymer composed of structural units derived from unsaturated monomers and crystalline thermoplastic resin. Compared with simple crystalline thermoplastic resin, the three-dimensional structure of the modified polymer is The regularity is destroyed or reduced, so the melting range of the modified polymer becomes wider and the relaxation time becomes longer.
  • pre-foamed materials containing the modified polymer for foaming there is no need to adjust the foaming temperature because of the broadened melting range. Particularly strict control is carried out, and the longer relaxation time of the pre-foamed material can increase the stable growth time of cells during the foaming process, which is beneficial to improving cell uniformity.
  • the melt strength of the above-mentioned modified polymer is higher Large, the melt strength of the pre-foamed material is correspondingly large, which can support the generation of cells during the foaming process, ensuring that most of the cells of the obtained pre-foamed material are closed cells, reducing its water absorption and improving its Mechanical strength, etc.
  • the term “relaxation time” in this application refers to the time required for an object to be deformed by an external force and return to its normal state after the external force is removed.
  • the relaxation time can be calculated based on Maxwell's constitutive equation model.
  • the above-mentioned pre-expanded material may specifically be foaming particles or pre-expanded particles, and its shape is not particularly limited, and may be cylindrical, spherical, ellipsoidal, strip-shaped, rod-shaped, block-shaped, sheet-shaped, etc.
  • the molecular chain ends of the modified polymer are capped by crystalline thermoplastic resin.
  • the "crystalline thermoplastic resin” here is precisely the part of the crystalline thermoplastic resin connected to the first structural unit, that is, the matrix of the crystalline thermoplastic resin.
  • the modified polymer has a structural formula represented by formula (I):
  • M 1 represents the first structural unit derived from an unsaturated monomer
  • m represents the degree of polymerization of M 1
  • P 1 is independently selected from crystalline thermoplastic resins.
  • the above-mentioned modified polymer may contain one kind of first structural unit, or contain a plurality of first structural units with different structures.
  • the two end-capping groups P 1 located at the ends of the molecular chains of the above-mentioned modified polymer may be the same or different types of crystalline thermoplastic resins.
  • the two P 1 in the above formula (I) are preferably the same.
  • the crystalline thermoplastic resin includes syndiotactic polystyrene (sPS), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy vinyl ether polymer, poly One or more of, but not limited to, polyphenylene sulfide (PPS), polyetheretherketone, and liquid crystal polymer.
  • sPS syndiotactic polystyrene
  • PTFE polytetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • PPS polyphenylene sulfide
  • the crystalline thermoplastic resin includes one or more of sPS, PTFE, polyphenylene sulfide, and liquid crystal polymer.
  • the melting point of polyphenylene sulfide is around 280°C
  • the dielectric loss factor Df can be around 0.002
  • the dielectric loss factor Df of PTFE can be around 0.005-0.0008.
  • the dielectric loss of liquid crystal polymer is between 0.0006 and 0.002.
  • Exemplary liquid crystal polymers can be type I and type II, and the corresponding heat-resistant thermal deformation temperatures are above 300°C and 240-280°C respectively.
  • the unsaturated monomer has unsaturated bonds such as carbon-carbon double bonds and carbon-carbon triple bonds in its molecular structure to exhibit a certain polymerization activity when preparing the above-mentioned pre-foamed material.
  • the unsaturated monomer has a carbon-carbon double bond in its molecular structure.
  • the unsaturated monomer may include one or more of styrene, maleic anhydride, pentaerythritol triacrylate, methacrylate, glycidyl methacrylate, and ethyl acrylate, but is not limited thereto.
  • Structural units derived from these monomers help to improve the melt strength of the above-mentioned modified polymer, which can effectively alleviate the delamination and mostly open cells of the foamed material obtained by foaming the above-mentioned pre-foamed material. problem, while having little impact on the dielectric properties of the modified polymer.
  • the modified polymer is obtained by reacting the following raw materials in parts by weight: 100 parts of crystalline thermoplastic resin matrix, 0.1-5 parts of unsaturated monomer, and 0.1-5 parts of initiator.
  • the initiator can cause the molecular chain of the crystalline thermoplastic resin to generate free radicals as reaction sites to initiate the polymerization reaction of unsaturated monomers, thereby producing a modified polymer with the above structure.
  • the introduction of initiators and unsaturated monomers causes micro-crosslinking of the crystalline thermoplastic resin, destroying its stereoregularity. Therefore, the melting range of the modified polymer becomes wider, the molecular entanglement increases, and the viscosity Increases the size and lengthens the relaxation time.
  • the initiator when preparing the modified polymer, the initiator should be mixed with the crystalline thermoplastic resin matrix first, and then the unsaturated monomer should be added to avoid the simultaneous mixing of the crystalline thermoplastic resin matrix, unsaturated monomer, and initiator.
  • the highly reactive unsaturated monomer When added, the highly reactive unsaturated monomer first undergoes a polymerization reaction under the action of the initiator without being blocked by the crystalline thermoplastic resin.
  • the amount of unsaturated monomer added is small, and its presence will not significantly affect the low dielectric properties of the modified polymer terminated by the above-mentioned crystalline thermoplastic resin, nor will it cause excessive micro-crosslinking of the modified polymer. And affect the molding processing performance.
  • the smaller amount of initiator also helps reduce the probability of self-polymerization of unsaturated monomers.
  • reaction formula for preparing the above modified polymer can be as follows:
  • the above-mentioned initiator may be an organic peroxy compound initiator, which can thermally decompose to generate free radicals as reaction sites on the molecular chain of the crystalline thermoplastic resin.
  • the initiator may include dicumyl peroxide (Dicumyl peroxide, abbreviated as DCP), di(tert-butylisopropylperoxy)benzene, 2,5-dimethyl-2,5-bis( One or more of tert-butylperoxy)hexane, 2-(tert-butylperoxyisopropyl)benzene, butanone peroxide, dibenzoyl peroxide, and lauroyl peroxide Limited to this.
  • DCP dicumyl peroxide
  • DCP di(tert-butylisopropylperoxy)benzene
  • 2,5-dimethyl-2,5-bis( One or more of tert-butylperoxy)hexane 2-(tert-butyl
  • the pre-foamed material also contains antioxidants.
  • the presence of antioxidants can improve the oxidation resistance of the modified polymer during the granulation process of the pre-foamed material, preventing it from aging and degradation due to heat and oxygen, and losing its use value.
  • the antioxidant may specifically include antioxidant 1010 (chemical name: tetrakis [ ⁇ -(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol), antioxidant 168 ( Chemical name: one or more of tris[2.4-di-tert-butylphenyl]phosphite), antioxidant 1790, etc., but not limited to this.
  • the mass of the antioxidant in the pre-foamed material, can be 0.09wt%-1wt% of the mass of the modified polymer, for example, specifically 0.1wt%, 0.3wt%, 0.5wt%, 0.6wt % or 0.9wt% etc.
  • the melting range of the modified polymer or the pre-foamed material is 15°C based on differential scanning calorimetry (DSC) at a heating rate of 10°C/minute. Above, the melting point is above 270°C.
  • the modified polymer or pre-foamed material has a wider melting range, which can reduce the difficulty of precise control of the foaming temperature during the foaming process; the modified polymer or pre-foamed material has a higher melting point, and is made of The resulting pre-foamed material has good heat resistance and is suitable for use in PCB boards with high requirements for high temperature resistance.
  • the melting range of the modified polymer or the pre-foamed material is above 20°C, or even above 25°C.
  • the embodiments of this application also provide a method for preparing the above-mentioned pre-foamed material, which includes the following steps:
  • the crystalline thermoplastic resin and the initiator are melt-blended, and then unsaturated monomers are added for melt-blending to prepare a pre-foamed material containing a modified polymer; wherein, under the action of the initiator, the The crystalline thermoplastic resin can cap the ends of the polymer obtained by the polymerization reaction of the unsaturated monomer to obtain the modified polymer.
  • the initiator is first melt-blended with the crystalline thermoplastic resin matrix, and then the unsaturated monomer is added. This is conducive to generating free radicals on the molecular chain of the crystalline thermoplastic resin as reaction sites.
  • To initiate the polymerization reaction of unsaturated monomers thereby producing modified polymers with the above structural characteristics and physical and chemical properties, avoiding the simultaneous addition of crystalline thermoplastic resin matrix, unsaturated monomers, and initiators that may cause highly reactive unsaturated monomers. Polymerization occurs under the action of an initiator without being blocked by crystalline thermoplastic resin. Therefore, the above-mentioned specific feeding sequence can ensure a higher yield of the above-mentioned modified polymer and a wider melting range of the pre-foamed material.
  • the unsaturated monomer is added to perform the melt blending.
  • the total time of melt blending may be 3-30 min, for example 5-20 min, further may be 5-10 min.
  • the temperature of melt blending can be 270-300°C, for example, 275, 280, 285, 290, 295°C.
  • the weight part of the initiator is 0.1-5 parts
  • the weight part of the unsaturated monomer is 0.1-5 parts.
  • the addition amount of initiator and unsaturated monomer is lower than that of crystalline thermoplastic resin, which is conducive to ensuring a higher yield of the above-mentioned modified polymer in the obtained product.
  • By-products (such as polymers of unsaturated monomers) less.
  • a lower amount of unsaturated monomer will not significantly affect the low dielectric properties and molding processability of the above-mentioned modified polymer (for example, it will not turn the modified polymer into a thermosetting resin and cannot be injection molded, etc.).
  • it can improve the melt strength of the modified polymer and reduce the probability of delamination and mostly open cells in the pre-foamed material during foaming.
  • the weight parts of the initiator can be 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts, 3 parts or 4 parts, etc.; In some embodiments, the weight part of the initiator is 0.2-2 parts.
  • the weight parts of the unsaturated monomer may be 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts, 3 parts, 4 parts or 4.5 parts parts, etc.; in some embodiments, the weight part of the unsaturated monomer is 0.2-4 parts, and further may be 0.2-2 parts.
  • antioxidants are also used when preparing the above-mentioned pre-foamed materials.
  • the antioxidant can be added entirely with the crystalline thermoplastic resin and the initiator; or all of the antioxidant can be added with the unsaturated monomer; or part of it can be added with the crystalline thermoplastic resin and the initiator, and the other part can be added with the unsaturated monomer.
  • the weight part of the initiator is 0.1-1 part, such as 0.2 part, 0.5 part, 0.6 part, 0.8 part or 0.9 part, etc.
  • the functions of antioxidants are as described previously in this application and will not be repeated here.
  • auxiliary agents when preparing the above-mentioned pre-foamed material, other auxiliary agents can also be added, and the other auxiliary agents will not affect the foaming performance of the pre-foamed material and the foamed cell structure. produce adverse effects.
  • the other auxiliary agents include but are not limited to: at least one of slip agent, antistatic agent, anti-sticking agent, plasticizer, flame retardant, etc.
  • the above-mentioned melt blending can be performed in a mixing equipment, where the mixing equipment can provide equipment for shearing, mixing, heating, and optional granulation and material transportation.
  • the mixing equipment can be a melting equipment. Extruder, Hacker mixer or double-stick open mixer, etc., but not limited to these.
  • the method of melt blending may be extrusion melt blending, Ralpher melt blending, double-roller melt blending, etc. Among them, extrusion melt blending and Haake mixing melt blending are closed melt blending, while double-roller melt blending is open melt blending.
  • the above-mentioned crystalline thermoplastic resin, initiator, and unsaturated monomer can be heated and melted in the extruder, and the screw of the extruder rotates at a certain rate to drive the molten state
  • the mixed materials are continuously extruded, mixed, and reacted.
  • the reacted materials can be extruded from the die head of the extruder into strips, and the strips are cut into granular shapes with the help of a rotating blade to obtain the granular above-mentioned pre-foamed material.
  • the above-mentioned crystalline thermoplastic resin, initiator, and unsaturated monomer can be heated and melted in the internal mixer, and sheared and kneaded by relying on the rotor movement in the internal mixer. After the reaction, the material is prepared into granules through scissors and other auxiliary equipment to obtain the above-mentioned pre-foamed material.
  • a double-stick open mill is used as the mixing equipment, the above-mentioned crystalline thermoplastic resin, initiator, and unsaturated monomer can be heated and melted in the double-stick open mill.
  • the twin sticks of the double-stick open mill face each other at a certain rate.
  • the rotation drives the molten mixed material to be continuously extruded, mixed and reacted.
  • the reacted material is a sheet sample, which can be prepared into granules with the help of scissors and other auxiliary equipment to obtain the above-mentioned pre-foamed material.
  • the modified polymer on the surface of the granulation chamber will It is not easy to orient and arrange along the mold, so there is no obvious difference in the arrangement of the modified polymer in the surface layer and the inner layer of the obtained pre-foamed material, which is beneficial to the foaming of the pre-foamed material to obtain a foamed material that is not easy to stratify. .
  • the shape of the above-mentioned pre-foamed material is not particularly limited and can be relatively small in size such as cylindrical, spherical, ellipsoid, strip, rod, block, sheet, etc.
  • the pre-foamed material is in the form of fragments. Before using the pre-foamed material for foaming, it can first be shaped into a product to be foamed with a certain shape, for example, transformed by hot pressing. The products to be foamed are formed into sheet form, and then the sheet products are directly used for foaming treatment.
  • the preparation method of the pre-foamed material provided by the application is simple to operate.
  • the modified polymer contained in the pre-foamed material has a novel structure, low regularity of the three-dimensional structure, wide melting range and high melt strength, which is beneficial to
  • the pre-foamed material is smoothly foamed to produce a foamed material that is not easy to delaminate, and its closed cell ratio, mechanical strength, etc. are improved.
  • embodiments of the present application also provide a foaming raw material that can be used to prepare the above-mentioned pre-foamed material.
  • the foaming raw material includes A component and B component, wherein the A component includes crystalline type thermoplastic resin and an initiator, the B component includes an unsaturated monomer; wherein, when the A component and the B component are melted and blended, under the action of the initiator, the crystalline thermoplastic resin The end of the polymer obtained by polymerizing the unsaturated monomer can be capped.
  • component A and component B are placed separately.
  • component A can be converted into a molten state first, and then component B is added, and through melting and blending reaction, A pre-foamed material containing modified polymer is prepared.
  • the molding method for converting the above-mentioned foaming raw materials into pre-foamed materials is not limited, and can be one of extrusion molding, injection molding, compression molding, blow molding, die-casting molding, vacuum molding, etc., or Various.
  • the weight part of the initiator is 0.1-5 parts, and the weight part of the unsaturated monomer is 0.1-5 parts.
  • the A component and/or B component also contains antioxidants or other auxiliaries. Wherein, based on 100 parts by weight of crystalline thermoplastic resin, the weight part of the antioxidant is 0.1-1 part.
  • the embodiments of the present application also provide a foaming material, which is obtained by foaming the pre-foamed material as described in the embodiments of the present application, or by foaming the raw materials as described in the embodiments of the present application. prepared.
  • the foamed material contains the above-mentioned modified polymer.
  • the foamed material can be directly foamed by using the above-mentioned pre-foamed material, or the pre-foamed material can be first processed into a product to be foamed corresponding to the shape of the foamed material, and then the pre-foamed material can be processed through The product is foamed.
  • the foaming is specifically supercritical foaming.
  • the preparation process of the foam material includes:
  • the pre-foamed material can be shaped into the product to be foamed under heating, so that the pre-foamed material is melted and integrated, for example, transformed into the product to be foamed with a certain shape by hot pressing.
  • the shape of the product to be foamed corresponds to the shape of the required foaming material, and the thickness of the two may be different. It is understandable that the thickness of the foaming material is larger than that of the product to be foamed.
  • the supercritical foaming process in step S2 may specifically include the following steps:
  • the supercritical foaming agent includes carbon dioxide (CO 2 , critical temperature is 31.1°C, critical pressure is 7.38MPa), nitrogen (N 2 , critical temperature is -147°C, critical pressure is 3.39MPa) or combination thereof, etc.
  • a co-foaming agent is also introduced into the foaming container in step S22.
  • the co-foaming agent may be one or more of ethanol, propanol, isopropyl alcohol, acetone, and ethyl acetate.
  • the presence of co-foaming agent can increase the absorption of supercritical foaming agent by the products to be foamed. It can be understood that the supercritical foaming agent and co-foaming agent should be inert to the article to be foamed.
  • the preset temperature can be set according to the melting point of the supercritical foaming agent and the modified polymer.
  • the preset temperature should be higher than the critical temperature of the supercritical foaming agent so that the foaming agent is in a supercritical state.
  • the preset pressure reached in the foaming container should be maintained higher than the critical pressure of the supercritical foaming agent, so that The foaming agent is in a supercritical state, which facilitates diffusion into the product to be foamed and reaches a higher solubility therein.
  • the impregnation process is to maintain the environment in the foaming container at the preset temperature and preset pressure for a period of time so that the product to be foamed absorbs a certain amount of supercritical foaming agent.
  • the preset temperature may be in the range of 270-300°C, such as 270, 275, 280, 285, 290°C, etc.; in step S22
  • the preset pressure of the foaming container may be in the range of 8-20 MPa, such as 9, 10, 12, 15, 18 or 20 MPa, etc.
  • step S23 after the product to be foamed is saturated with the supercritical foaming agent (or after the supercritical foaming agent reaches a dissolution equilibrium), the pressure in the foaming container can be released at once or in stages, This process can also be called “pressure relief", that is, the pressure in the foaming container is reduced, for example, to atmospheric pressure.
  • pressure relief a large number of cell cores will be generated in the product to be foamed, and the cell cores will continue to grow to obtain a foamed material with cells.
  • the pressure within the foaming container is reduced to atmospheric pressure at a rate of 0.8-10 MPa/s.
  • the time taken for pressure relief can be 2-10 seconds.
  • the foaming device 200 may include:
  • Temperature control system 22 is used to heat the foaming container 21 to reach a preset temperature
  • the high-pressure conveying system 23 is used to convey the supercritical foaming agent into the foaming container 21 so that the pressure of the foaming container 21 reaches the preset pressure;
  • the pressure relief system 24 is used to release the pressure in the foaming container 21 after the supercritical foaming agent impregnates the product 201 to be foamed and is saturated, so that the product 201 to be foamed is foamed and a foamed material is obtained.
  • the temperature control system 22 includes a heating component 221 and a temperature sensor 222.
  • the heating component 221 is used to provide a heat source to the foaming container 21 so that the temperature in the foaming container 21 reaches a preset value.
  • the temperature sensor 222 Used to monitor the temperature inside the foaming container 21.
  • the foaming container 21 may be specifically a foaming mold.
  • the high-pressure delivery system 23 includes a fluid source 231 (usually a gas source, such as CO 2 , N 2 , etc.), a pump 232 , an air inlet pipeline 233 and an air inlet valve 234 , wherein the pump 232 pipeline is connected to the fluid Between the source 231 and the foaming container 21; the cavity of the foaming container 21 and the pump 232 are connected through an air inlet pipe 233, and an air inlet valve 234 is provided on the air inlet pipe 233.
  • the air inlet valve 234 can regulate the flow rate of the supercritical foaming agent delivered to the foaming container 21, the pressure of the foaming container 21, and the like.
  • the foaming container 21 is also provided with a pressure sensor 202.
  • the number of air inlet pipes 233, the number of air inlet valves 234, the number of fluid sources 231, etc. may be one or more, which may be determined based on the type of supercritical foaming agent, whether a co-foaming agent is used, etc.
  • the pressure relief system 24 includes a pressure relief channel 241 connected with the foaming container 21.
  • the pressure relief channel 241 is provided with a pressure relief valve 242 to release the pressure in the foaming container 21 when necessary.
  • the foaming container 21 is provided with an air inlet I 1 and an air outlet O 1
  • the air inlet pipe 233 is connected to the foaming container 21 through the air inlet I 1
  • the pressure relief channel 241 is connected to the foaming container 21 through the air outlet O 1 .
  • the bubble container 21 is connected.
  • the foaming container 21 may also be directly provided with a pressure relief valve.
  • the foaming device 200 also includes a hydraulic system 25 for providing pressure to close the foaming container 21 in which the product to be foamed 201 is placed, so that the foaming container 21 reaches a closed state to facilitate its operation. Heating, transporting fluids, etc. It can be understood that the hydraulic system 25 is connected with the cavity of the foaming container 21 .
  • the shape of the above-mentioned foam material is not limited, and may be, for example, sheet-shaped, block-shaped, rod-shaped, tube-shaped, column-shaped, or other shapes.
  • the foam material when used in a PCB board, such as specifically used as the dielectric layer sheet 11 in Figure 1, the foam material can be in the form of a sheet, or the foam material can be Called "foam sheet".
  • the foamed material has a porous structure.
  • most of the cells in the foam material are closed cells.
  • the closed cell ratio of the foam material (also called “closed cell ratio”) is above 50%, for example, above 55%, above 60%, or even above 80%.
  • a higher cell closed cell ratio helps ensure that the foam material has excellent water absorption resistance.
  • the closed cell ratio can be 50%, 52%, 55%, 58%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 99% or 100%, etc.
  • the closed cell ratio of the foam material may be 50%-80%, and further may be 50%-60%.
  • the closed cell ratio of foamed materials can be measured according to the GB/T 10799-2008 standard.
  • the water absorption rate of the foamed material after being placed in water for 24 hours at a temperature of 23°C and a relative humidity of 50% is less than 1%.
  • Lower water absorption is beneficial to extending the service life of the foam material, especially in humid environments.
  • the above-mentioned water absorption rate of the foam material is below 0.8%, and in some cases may be below 0.7%, or even below 0.6%, etc.
  • the above water absorption rate was tested using GB_T 8810-2005.
  • the average cell size of the foam material is in the range of 5-100 ⁇ m.
  • the average cell size may refer to the average of the maximum widths of the open cross-sections of each cell.
  • the average cell size of the foamed material is small.
  • the above-mentioned foamed material is used as the dielectric layer sheet 11 of the laminate 10 in the PCB board, it can be realized by means of a metal film (such as a copper film) plated in the cells.
  • the conduction of part of the circuits on the upper and lower metal foils in the laminate 10 is beneficial to shortening the conduction distance of the circuits.
  • the average cell diameter of the foam material is 10 ⁇ m-60 ⁇ m.
  • the density of the foam material is below 1 g/cm 3 .
  • the apparent density of porous foam can be tested according to the GB/T6343-2009 standard.
  • Lower-density foam materials are conducive to lightweighting devices using them.
  • the density of the foamed material is 0.1-0.8g/cm 3 ; in other embodiments, the density of the foamed material is 0.2-0.6g/cm 3 , or even 0.2-0.4 g/cm 3 .
  • the dielectric constant Dk of the foam material under electromagnetic waves with a frequency of 10 GHz is measured to be below 2.0, and the dielectric loss Df is below 0.0015. It can be known from this that the dielectric properties of the foam material are relatively good. Using it to make PCB boards will have less impact on signal delay and attenuation, allowing the PCB board to meet high-frequency and high-speed communication needs.
  • the dielectric constant Dk and the dielectric loss Df can be measured according to the split dielectric resonator (splite post dielectric resonator, abbreviated as SPDR) method, and the test frequency is 10GHz.
  • the embodiments of the present application also provide the use of the above-mentioned pre-foamed materials, the above-mentioned foaming materials, and the above-mentioned foaming raw materials in preparing printed circuit boards (specifically used as low-dielectric materials for printed circuit boards), buffering materials, shock-absorbing materials, insulation materials, etc. Application in thermal materials, sound-absorbing materials and medium lightweight materials. Among them, printed circuit boards, buffer materials, thermal insulation materials, sound-absorbing materials, etc. can be produced through foaming methods.
  • pre-foamed materials, foamed materials, and foaming raw materials mentioned in this application are not limited to the production of printed circuit boards, cushioning materials, shock-absorbing materials, etc., but can also be used in other applications as needed. Scenes.
  • pre-foamed materials, foaming materials and foaming raw materials are used to prepare printed circuit boards, they can be specifically used as dielectric materials in laminates in printed circuit boards. Furthermore, when they are used to prepare buffer materials, they can particularly serve as buffer structures for adjacent components or adjacent layers in electronic assemblies.
  • embodiments of the present application provide a laminate, which includes the above-mentioned foaming material in the embodiments of the present application.
  • Printed circuit boards can be produced using this laminate.
  • the structure of the laminate is as described in Figure 1 of the present application.
  • the laminate 10 includes a dielectric layer sheet 11 and a metal foil 12 located on the surface of the dielectric layer sheet 11.
  • the dielectric layer sheet 11 can be the one described in the embodiment of the present application. foam material.
  • the laminate may also be referred to as a "metal-clad laminate.”
  • the dielectric layer sheet in the laminate has lower dielectric properties, lower water absorption and lighter density, and is suitable for making lightweight, high-frequency and high-speed printed circuit boards.
  • the metal foil 12 can be placed on one side surface or opposite two side surfaces of the dielectric layer sheet 11 .
  • the metal foil 12 may be copper foil, aluminum foil, nickel foil, silver foil or alloy foil thereof. Among them, copper foil is more common, and the laminate 10 with copper foil can be called a "copper-clad laminate".
  • the above-mentioned laminate 10 can be produced by the following method: take the above-mentioned foam material as the dielectric layer sheet 11, place metal foil 12 on one side surface or the opposite sides of the surface, and heat and press to obtain the laminate 10.
  • An embodiment of the present application also provides a printed circuit board, which includes at least one laminate described above in the embodiment of the present application.
  • the printed circuit board may include one of the above-mentioned laminates, or a laminated structure of at least two laminates. Multiple laminates can be laminated by heat pressing.
  • circuits are provided on the metal foil 12 of the above-mentioned laminate 10 .
  • a photosensitive film can be attached to the surface of the metal foil 12 of the laminate 10, and the photosensitive film can be exposed and developed under a circuit mask to obtain a patterned photosensitive layer, which can be used as a mask to etch the copper foil.
  • the photosensitive film is then removed to obtain a laminate with circuit patterns.
  • a plurality of laminates 10 with circuit patterns can be heat-pressed and laminated to obtain a laminate. By drilling holes in the laminated board and chemically precipitating copper on the hole walls, signal conduction between different laminated boards can be achieved.
  • the solder resist layer can be brushed on the outer circuit pattern of the laminated board and surface treated. , complete printed circuit boards are available.
  • An embodiment of the present application also provides an electronic component, which includes the printed circuit board mentioned above in the embodiment of the present application.
  • the electronic component may also include various electronic components attached to the printed circuit (such as various chips, transistors, LED devices, resistor-capacitor components (such as resistors, capacitors, inductors)). ), etc.), as well as the plastic packaging structure covering them.
  • An embodiment of the present application also provides an electronic device, which includes the electronic component described in the embodiment of the present application or the printed circuit board described in the embodiment of the present application.
  • the electronic device can be a mobile phone, tablet computer, laptop computer, desktop computer, wearable device (such as smart watch, smart bracelet), portable machine, base station antenna, automotive radar and other products.
  • the embodiments of the present application also provide a modified polymer, which has a structural formula represented by formula (I):
  • M 1 represents the first structural unit derived from an unsaturated monomer
  • m represents the degree of polymerization of M 1
  • P 1 is independently selected from crystalline thermoplastic resins. The introduction of the unsaturated monomer and crystalline thermoplastic resin is as described previously in this application.
  • the melting range of the modified polymer at a heating rate of 10°C/min is above 15°C and the melting point is above 270°C based on differential scanning calorimetry.
  • the modified polymer is suitable for use as a raw material for the preparation of pre-foamed materials to produce foamed materials with high closed cell ratio and difficulty in delamination.
  • the embodiments of this application also provide the application of the modified polymers described in the embodiments of this application in preparing foaming materials, plastic sealing materials, adhesives, and resin compositions.
  • the above-mentioned modified polymer can be used to prepare the above-mentioned foaming raw material, the above-mentioned pre-foamed material, products to be foamed, foamed materials, etc.
  • the above-mentioned modified polymer can also be used as plastic packaging materials, adhesives, etc., which can be made into plastic packaging materials, adhesives, etc. by injection molding, injection, molding, pouring or coating.
  • At least one refers to one or more
  • plural refers to two or more.
  • At least one of the following” or similar expressions thereof refers to any combination of these items, including any combination of a single item (items) or a plurality of items (items).
  • at least one of a, b or c or “at least one of a, b and c” can mean: a, b, c, a-b (that is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.
  • a certain parameter range is “below c" or "above d"
  • this number is included.
  • the meaning includes the original number c and any value smaller than c.
  • the number is also included, which means that it includes the endpoint value e, the endpoint value f, and any value between e and f.
  • sPS syndiotactic polystyrene
  • DCP initiator dicumyl peroxide
  • antioxidant 1010 0.25 parts by weight of antioxidant 168
  • the rotation speed of the Haake internal mixer is 50 rpm and the melt blending temperature is 285°C. Add it to the Haake internal mixer after 30 seconds. 0.5 parts by weight of the double bond-containing monomer - styrene, is continued to be melt blended, and the total melt blending time is 5 minutes.
  • the foaming particles contain the following modified polymer P1, which is obtained by sPS resin end-capping the polymer obtained by the polymerization reaction of styrene monomer under the action of an initiator. arrive.
  • reaction formula involved in the above melt blending process is as follows:
  • the melting point of the foaming particles containing the above-mentioned modified polymer P1 was measured to be 273°C, the melting range was 25°C, and the relaxation time was about 33 seconds.
  • Example 1 (1) Put the above-mentioned foaming particles of Example 1 into a disc mold with a diameter of 50 mm, and press it on a flat vulcanizer.
  • the pressing temperature is 285°C
  • the pressure is 10MPa
  • the pressing time is 5 minutes. After the lamination is completed, take it out from the mold to obtain a 50 mm diameter disc containing the improved polymer P1 as the product to be foamed.
  • Figure 3 is a scanning electron microscope (SEM) photo of the foam material obtained in Example 1 of the present application. It can be seen from Figure 3 that the cell size of the foam material is relatively uniform, and most of them are closed cells. Based on this, the average cell size can be calculated to be 30 ⁇ m.
  • the density of the foamed material obtained in Example 1 was measured to be 0.38g/cm 3 , the closed cell rate was 50.4%, the water absorption rate was 0.54%, and the flexural strength was 3.5MPa;
  • the dielectric constant Dk of the foam material under the electromagnetic wave frequency of 10GHz is 1.7, and the dielectric loss Df is 0.0006.
  • Example 2 The difference between Example 2 and Example 1 is that when preparing the particles for foaming, 0.5 parts by weight of pentaerythritol triacrylate (PETA) is used to replace the styrene monomer used in Example 1.
  • PETA pentaerythritol triacrylate
  • the foaming particles of Example 2 contain the following modified polymer P2.
  • P2 is obtained by end-capping the polymer obtained by polymerizing PETA monomer with sPS resin under the action of the initiator DCP.
  • the melting point of the foaming particles containing the above-mentioned modified polymer P2 was measured to be 272°C, the melting range was 20°C, and the relaxation time was about 22s.
  • Example 2 According to the method described in Example 1, the foaming particles obtained in Example 2 were prepared into a foaming material.
  • Figure 4 is an SEM photo of the foam material obtained in Example 2 of the present application. It can be seen from Figure 4 that the cell size of the foam material is relatively uniform, and most of them are closed cells. Based on this, the average cell size can be calculated to be 40 ⁇ m.
  • the density of the foamed material obtained in Example 2 was measured to be 0.36g/cm 3 , the closed cell rate was 56.3%, the water absorption rate of the foamed material was 0.59%, and the flexural strength was 3.3MPa; the foamed material was Under the electromagnetic wave frequency of 10GHz, the dielectric constant Dk is 1.5 and the dielectric loss Df is 0.0005.
  • Example 3 The difference between Example 3 and Example 1 is that when preparing the particles for foaming, 0.5 parts by weight of maleic anhydride (MA) is used to replace the styrene monomer used in Example 1, and the initiator BPO is used instead of Example 1. DCP used.
  • the foaming particles of Example 3 contain the following modified polymer P3.
  • P3 is obtained by end-capping the polymer obtained by polymerizing MA monomer with sPS resin under the action of the initiator BPO.
  • the melting point of the foaming particles containing the above-mentioned modified polymer P3 was measured to be 274°C, the melting range was 28°C, and the relaxation time was about 36 s.
  • Example 3 According to the method described in Example 1, the foaming particles obtained in Example 3 were prepared into a foaming material.
  • the average cell size of the foamed material obtained in Example 3 was measured to be 50 ⁇ m, the closed cell ratio was 54.5%, the density of the foamed material was 0.32g/cm 3 , the water absorption rate was 0.61%, and the flexural strength was 3.8 MPa; the dielectric constant Dk of this foam material under electromagnetic waves with a frequency of 10GHz is 1.5, and the dielectric loss Df is 0.0005.
  • Example 4 The difference between Example 4 and Example 1 is that when preparing the foaming material, the product to be foamed and obtained by molding the foaming particles in Example 1 was immersed in CO 2 for 40 minutes at a foaming temperature of 275°C.
  • the average cell size of the foamed material obtained in Example 4 was measured to be 5 ⁇ m, the cell closed cell rate was 75%, the density of the foamed material was 0.7g/cm 3 , the water absorption rate was 0.15%, and the flexural strength was 10MPa;
  • the dielectric constant Dk of the foam material under the electromagnetic wave frequency of 10GHz is 1.9, and the dielectric loss Df is 0.0006.
  • Example 5 The difference between Example 5 and Example 2 is that when preparing the foaming material, the product to be foamed formed by the foaming particles of Example 2 was immersed in CO 2 for 40 minutes at a foaming temperature of 275°C.
  • the average cell size of the foamed material obtained in Example 5 was measured to be 8 ⁇ m, the cell closed cell rate was 65%, the density of the foamed material was 0.65g/cm 3 , the water absorption rate was 0.35%, and the flexural strength was 7.5MPa;
  • the dielectric constant Dk of this foam material under electromagnetic waves with a frequency of 10 GHz is 1.8, and the dielectric loss Df is 0.0006.
  • Example 6 when preparing particles for foaming, the weight ratio of sPS, initiator, and styrene monomer is 100:0.1:0.2.
  • the melting point of the foaming particles obtained in Example 6 was measured to be 274°C, the melting range was 27°C, and the relaxation time was about 35 s.
  • the foaming particles obtained in Example 6 were prepared into a foaming material.
  • the average cell size of the foamed material obtained in Example 6 was measured to be 25 ⁇ m, the cell closed cell rate was 59%, the density of the foamed material was 0.35g/cm 3 , the water absorption rate was 0.57%, and the flexural strength was 3.4 MPa; the dielectric constant Dk of this foam material under electromagnetic waves with a frequency of 10GHz is 1.7, and the dielectric loss Df is 0.0007.
  • Preparation of particles for foaming In an aluminum foil bag, add 100 parts by weight of sPS resin particles, 0.25 parts by weight of antioxidant 1010 and 0.25 parts by weight of antioxidant 168, stir evenly and add to a Hacker mixer. Melt blending and internal mixing (the rotation speed of the Haake internal mixer, the temperature of the melt blending and the total time are the same as in Example 1). After the melt blending is completed, the obtained sample is taken out from the Haake internal mixer and cut into long widths with scissors. The fragments with a size of 3mm ⁇ 3mm are the required foaming particles.
  • Preparation of foaming material The above-mentioned foaming particles of Comparative Example 1 were processed into a foaming material in the manner described in Example 1. The difference from Example 1 is that the foaming temperature was 265°C for 40 minutes. .
  • the melting point of the foaming particles obtained in Comparative Example 1 was measured to be 271°C, the melting range was 8.6°C, and the relaxation time was about 9 seconds.
  • the closed cell ratio of the cells is as low as 20%.
  • the density of the foam material is 0.44g/cm 3 , the water absorption rate is as high as 13.84%, and the flexural strength is only 2MPa; the dielectric constant Dk of the foam material under electromagnetic waves with a frequency of 10GHz is 1.5, and the dielectric loss Df is 0.0004 .
  • Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that when preparing particles for foaming, sPS, initiator DCP, and styrene monomer are simultaneously added to a Haake internal mixer for melt blending.
  • the melting point of the foaming particles obtained in Comparative Example 2 is 273°C, the melting range is 13.9°C, and the relaxation time is about 21 seconds.
  • the closed cell ratio is only 20%
  • the density of the foamed material is 0.40g/cm 3
  • the water absorption rate is 14.60%
  • the flexural strength is 1.7MPa
  • the dielectric constant Dk of this foam material under electromagnetic waves with a frequency of 10GHz is 1.6
  • the dielectric loss Df is 0.0006.
  • Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that when preparing particles for foaming, sPS, initiator DCP, and pentaerythritol triacrylate (PETA) are simultaneously added to a Haake internal mixer for melt blending.
  • sPS sPS
  • initiator DCP initiator DCP
  • PETA pentaerythritol triacrylate
  • the melting point of the foaming particles obtained in Comparative Example 3 is 273°C, the melting range is 14.5°C, and the relaxation time is about 21 s.
  • the closed cell ratio is only 20%
  • the density of the foamed material is 0.47g/cm 3
  • the water absorption rate is 13.10%
  • the flexural strength is 2.2MPa
  • the dielectric constant Dk of this foam material under electromagnetic waves with a frequency of 10GHz is 1.7
  • the dielectric loss Df is 0.0006.
  • the melting range of the foaming particles containing the modified polymer of the present application is significantly higher than that of Comparative Example 1, and can be increased to above 15°C, or even 20°C. Above; its relaxation time can be increased to more than 30s.
  • the foaming particles of the present application are particularly suitable for foaming into foamed materials through supercritical foaming.
  • the temperature of the foaming process does not need to be controlled in a particularly narrow range, which reduces the difficulty of temperature control; and the foaming particles A longer relaxation time is beneficial to improving the cell uniformity of the resulting foamed material.

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Abstract

本申请实施例提供了一种预发泡材料及其制备方法、发泡材料及其发泡装置、改性聚合物及它们的相关应用等。其中，预发泡材料包括改性聚合物，该改性聚合物具有源自不饱和单体的第一结构单元，且该改性聚合物的分子链末端封端有结晶型热塑性树脂。该预发泡材料中所含改性聚合物的结构新颖，其立构规整度低，熔程较宽、松弛时间较长，适合通过超临界发泡法发泡制得发泡材料，且发泡材料不易分层、闭孔率高、吸水率低、机械性能好。

Description

预发泡材料及其制备方法和应用
本申请要求于2022年8月10日提交至中国专利局、申请号为202210956656.5、申请名称为“预发泡材料及其制备方法和应用”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及发泡材料技术领域，具体涉及一种预发泡材料及其制备方法和应用。
背景技术
印制电路板(Printed Circuit Board，简写为PCB)广泛应用于基站天馈系统以及手机、电脑等设备中，随着通讯技术朝高频高速的方向发展，对PCB板提出了更高的要求，具有低介电常数、低介电损耗、轻量化的PCB介质层材料是PCB市场的主要发展方向之一。
间规聚苯乙烯(Syndiotactic polystyrene，简写为sPS)因具有高熔点、低密度、低吸水率、优异的高频介电性能而被认为是高频PCB的潜在介质层材料之一。但sPS材料是一种结晶性材料，其熔程较窄，难以通过超临界发泡得到轻量化的介质层，而直接采用超临界发泡法制得的sPS发泡材料易出现分层，且泡孔多为开孔、吸水率较高，无法满足PCB板的要求。因此，有必要提供一种吸水率低、介电性能好的发泡材料。
发明内容
鉴于此，本申请实施例提供了一种介电常数和介电损耗低、吸水率低的发泡材料及其制备原料、应用等。
具体地，本申请实施例第一方面提供了一种预发泡材料，所述预发泡材料包括改性聚合物，所述改性聚合物具有源自不饱和单体的第一结构单元，所述改性聚合物的分子链末端封端有结晶型热塑性树脂。
上述预发泡材料中的改性聚合物是源自不饱和单体的结构单元与结晶型热塑性树脂共同构成的新型聚合物，该改性聚合物的立体结构的规整度较低，因此其熔程较宽，进而采用该预发泡材料进行发泡时的发泡温度无需控制在特别窄的窗口；该改性聚合物在预发泡材料的表层和内层中的排布程度无明显差别，进而采用该预发泡材料发泡所得的发泡材料不易出现分层现象；此外，相较于单纯的结晶型热塑性树脂，该改性聚合物的存在增加了预发泡材料的熔体强度，可保证所得发泡材料的泡孔大部分是闭孔，吸水率较低。
本申请实施方式中，所述结晶型热塑性树脂包括间规聚苯乙烯、聚四氟乙烯、聚偏氟乙烯、全氟烷氧基乙烯基醚聚合物、聚苯硫醚、聚醚醚酮、液晶聚合物中的一种或多种。这些结晶型热塑性树脂通常具有良好的耐热性和低介电性能，更适合用作制作PCB板的发泡原料。
本申请实施方式中，所述不饱和单体包括苯乙烯、马来酸酐、季戊四醇三丙烯酸酯、甲基丙烯酸酯、甲基丙烯酸缩水甘油酯、丙烯酸乙酯中的一种或多种。源自这些单体的结构单元有助于提升上述改性聚合物的熔体强度，进而可有效缓解上述预发泡材料的发泡材料发生分层和泡孔多是开孔的问题，同时对改性聚合物的介电性能影响较小。
本申请实施方式中，所述改性聚合物具有式(Ⅰ)所示的结构式：
式(Ⅰ)中，M1代表源自不饱和单体的第一结构单元，m代表所述M1的聚合度，P1独立地选自结晶型热塑性树脂。
本申请实施方式中，所述预发泡材料通过以下重量份数的各原料反应得到：结晶型热塑性树脂基体100份，不饱和单体0.1-5份，引发剂0.1-5份。较少用量的引发剂、不饱和单体有助于保证上述改性聚合物的得率较高，而副产物-不饱和单体的聚合物较少。
本申请实施方式中，所述引发剂包括过氧化二异丙苯、二(叔丁基过氧化异丙基)苯、2,5-二甲基-2,5-双(叔丁基过氧)己烷、2-(叔丁基过氧化异丙基)苯、过氧化丁酮、过氧化二苯甲酰、过氧化十二酰中的一种 或者多种。引发剂可以致使结晶型热塑性树脂的分子链上产生自由基以作为反应位点，引发不饱和单体的聚合反应，从而制得具有上述结构的改性聚合物。
本申请实施方式中，所述预发泡材料中还含有抗氧化剂。其中，所述抗氧化剂的质量是所述改性聚合物质量的0.09wt％-1wt％。适量抗氧化剂的加入可利于提升预发泡材料在制造/使用过程的稳定性。
本申请实施方式中，所述预发泡材料基于差示扫描量热法在10℃/分钟的加热速率下的熔程在15℃以上，熔点在270℃以上。这利于降低预发泡材料在发泡过程中对发泡温度的精密控制难度，保证所得发泡材料的良好耐热性。
本申请实施例第二方面提供了一种发泡材料，所述发泡材料通过本申请实施例第一方面所述的预发泡材料发泡得到。在一些实施方式中，该发泡具体是超临界发泡。
本申请实施方式中，所述发泡材料中的泡孔大部分是闭孔。闭孔的泡孔利于保证发泡材料具有优良的抗吸水性。
本申请实施方式中，所述发泡材料在温度为23℃、相对湿度为50％的环境下放置在水中24小后的吸水率在1％以下。较低的吸水率有利于提升发泡材料的使用寿命。
本申请实施方式中，所述发泡材料的平均泡孔尺寸在5-100μm的范围内。
本申请实施方式中，所述发泡材料的密度在1g/cm3以下。低密度的发泡材料，有利于保证采用其的器件的轻量化。
本申请实施方式中，基于谐振腔法测得所述发泡材料在频率为10GHz的电磁波下的介电常数在2.0以下，介电损耗在0.0015以下。该发泡材料的介电性能较优良，适合制作高频高速的PCB板。
本申请实施例第三方面提供了一种预发泡材料的制备方法，包括以下步骤：
先将结晶型热塑性树脂与引发剂进行熔融共混，之后加入不饱和单体进行熔融共混，制得含改性聚合物的预发泡材料；其中，在所述引发剂的作用下，所述结晶型热塑性树脂能将所述不饱和单体发生聚合反应得到的聚合物的末端封端而得到改性聚合物。
上述特定的加料顺序可保证上述改性聚合物的得率较高，且预发泡材料的熔程较宽。
本申请实施方式中，基于100重量份的所述结晶型热塑性树脂，所述引发剂的重量份为0.1-5份，所述不饱和单体的重量份是0.1-5份。引发剂和不饱和单体相较于结晶型热塑性树脂的加入量较低，这样有利于保证预发泡材料中改性聚合物的得率较高，副产物较少。
本申请实施例第四方面提供了一种制备发泡材料的发泡装置，包括：
发泡容器，用于放置待发泡制品，所述待发泡制品为本申请实施例第一方面所述的预发泡材料或所述预发泡材料的成型品；
温控系统，用于对所述发泡容器进行加热，以达到预设温度；
高压输送系统，用于向所述发泡容器内输送超临界发泡剂，以使所述发泡容器的压力达到预设压力；
释压系统，用于在所述超临界发泡剂浸渍所述待发泡制品饱和后，释放所述发泡容器内的压力，以使所述待发泡制品发泡，形成所述发泡材料。
采用上述发泡装置对含有前述改性聚合物的待发泡制品进行发泡，可以得到泡孔均匀、闭孔率高、不易分层的发泡材料。
本申请实施例第五方面提供了一种发泡用原料，包括A组分和B组分，其中，所述A组分包括结晶型热塑性树脂及引发剂，所述B组分包括不饱和单体；其中，所述A组分和B组分在熔融共混时，在所述引发剂的作用下，所述结晶型热塑性树脂能将所述不饱和单体聚合得到的聚合物的末端封端。
其中，A组分和B组分分开放置，在使用该发泡用原料制备上述预发泡材料时，可先将A组分转变为熔融态，之后加入B组分，经熔融共混反应，制得含上述改性聚合物的预发泡材料。
本申请实施例第六方面提供了本申请实施例第一方面所述的预发泡材料、本申请实施例第五方面所述的发泡用原料在制备发泡材料中的应用。该发泡材料也可称为发泡材料。
本申请实施例第七方面提供了本申请实施例第一方面所述的预发泡材料、本申请实施例第二方面所述的发泡材料、本申请实施例第五方面所述的发泡用原料在制备印刷电路板、缓冲材料、减震材料、隔热材料、吸音材料中的应用。其中，在制备印刷电路板、缓冲材料、减震材料、隔热材料、吸音材料等的制备中，可用到发泡法。即，印刷电路板、缓冲材料、减震材料、隔热材料、吸音材料等可以包括发泡材料。
本申请实施例第八方面提供了一种层压板，所述层压板包括介质层片材及位于所述介质层片材表面的金属箔，其中，所述介质层片材包括本申请实施例第二方面所述的发泡材料。该层压板中的介质层片材具有较低介电性能、较低吸水率及较轻密度，适合制作轻质、高频高速的印刷电路板。
本申请实施例第九方面提供了一种印刷电路板，所述印刷电路板包括至少一个如本申请实施例第八方面所述的层压板。
本申请实施例第十方面提供了一种电子组件，所述电子组件包括本申请实施例第九方面所述的印刷电路板。
本申请实施例第十一方面提供了一种电子设备，所述电子设备包括本申请实施例第十方面的电子组件或本申请实施例第九方面所述的印刷电路板。采用本申请实施例的电子组件或印刷电路板，可以改善电子设备的性能。
本申请实施例还提供了一种改性聚合物，所述改性聚合物具有式(Ⅰ)所示的结构式：
式(Ⅰ)中，M1代表源自不饱和单体的第一结构单元，m代表所述M1的聚合度，P1独立地选自结晶型热塑性树脂。该改性聚合物的立构规整度较低，其熔程较宽、其熔体强度大。
本申请实施例还提供了上述改性聚合物在制备发泡材料、塑封材料、胶黏剂、树脂组合物中的应用。
附图说明
图1为本申请实施例提供的PCB板中层压板的结构示意图。
图2为本申请实施例提供的制备发泡材料所用发泡装置的示意图。
图3为本申请实施例1所得发泡材料的扫描电子显微镜照片。
图4为本申请实施例2所得发泡材料的扫描电子显微镜照片。
图5为对比例1所得发泡材料的扫描电子显微镜照片。
具体实施方式
下面结合本申请实施例中的附图对本申请实施例进行描述。
PCB板通常通过多个层压板热压而成，如图1所示，层压板10一般包括介质层片材11及位于介质层片材11至少一侧表面上的金属箔12。该层压板10一般是覆铜板(Copper Clad Laminate，简写为CCL)，该CCL可包括介质层片材11及形成于介质层片材11相对两侧表面的铜箔。其中，PCB板中信号传输是在金属箔12中进行的，金属箔12之间的介质层片材11起到隔离金属箔12的作用，介质层片材11的介电常数越低，其对信号的延迟影响就越小，介质层片材11的介电损耗越低，其对信号的衰减影响就越小。因此随着通讯技术的信号传输频率及传输速率越来越高，对信号低延迟、低衰减的要求也越来越高，制备低介电常数、低介电损耗的介质层材料是未来PCB线路基板的发展趋势。此外，考虑到PCB板的装配和运输便利度，对PCB板的轻量化要求也越来越高。因此，需要提供轻质、介电性能良好的介质层材料。
为匹配高频高速的通讯技术，本申请实施例提供了一种预发泡材料，其适合通过发泡法制备PCB板中的上述介质层片材11，赋予发泡材料—介质层片材11良好的介电性能以及较轻的密度、较低的吸水率等。
具体地，本申请实施例提供了一种预发泡材料，所述预发泡材料包括改性聚合物，其中，所述改性聚合物具有源自不饱和单体的第一结构单元，所述改性聚合物的分子链末端封端有结晶型热塑性树脂封端。
结晶型热塑性树脂一般具有熔点，且分子排列较整齐，而分子排列越整齐，结晶型热塑性树脂的熔程就越窄，采用其发泡时对发泡温度的精密控制程度就较高。此外，采用未改性的结晶型热塑性树脂制造预发泡材料时，例如注塑成型过程中，由于结晶型热塑性树脂的立体结构规整度高，表层的高分子容易沿着模具进行取向排布，这使得所得预发泡材料(具体是发泡用粒子)的表层和内层结构不一致，一般是表层结构较致密，这使得采用预发泡材料进行超临界发泡时，溶解到表层的超临界气体少，溶解到内层的超临界气体多，在快速卸压产生泡孔的同时，所得发泡材料也易分层。另外，结晶型热塑性树脂的熔体强度较低，支撑不住泡孔的生长，发泡所得的泡孔大部分是开孔，发泡材料的吸水率较低。
而本申请提供的改性聚合物是源自不饱和单体的结构单元与结晶型热塑性树脂共同构成的新型聚合物，相较于单纯的结晶型热塑性树脂，该改性聚合物的立体结构的规整度被破坏或被降低，因此该改性聚合物的熔程变宽、松弛时间变长，当采用含有该改性聚合物的预发泡材料进行发泡时，因其熔程变宽无需对发泡温度进行特别严格的控制，且因预发泡材料的松弛时间变长能提高发泡过程中泡孔的稳定生长时间，利于提升泡孔均匀性。再者，由于上述改性聚合物的立体结构规整度较低，含有其的预发泡材料中，表层和内层的聚合物的分子排列程度无明显差别，这使得采用预发泡材料进行超临界发泡时，溶解在预发泡材 料的表层和内层中的超临界气体的量基本一致，进而所得预发泡材料不易出现分层现象；此外，相较于单纯的结晶型热塑性树脂，上述改性聚合物的熔体强度较大，预发泡材料的熔体强度也相应较大，在发泡过程中可以支撑住泡孔的产生，保证所得预发泡材料的泡孔大部分是闭孔，降低其吸水率、提升其机械强度等。
其中，本申请中词语“松弛时间”是指物体受外力变形，在外力解除后物体恢复至正常状态下所需要的时间。松弛时间可根据麦克斯韦(Maxwell)本构方程模型计算得到。上述预发泡材料可以具体是发泡用粒子或预发泡粒子，其形状没有特别限定，可以是圆柱状、球状、椭球状、条状、棒状、块状、片状等。本申请中，上述改性聚合物的分子链末端被结晶型热塑性树脂封端。这里的“结晶型热塑性树脂”准确来说是与第一结构单元连接的结晶型热塑性树脂部分，也即结晶型热塑性树脂的母体。
本申请实施方式中，所述改性聚合物具有式(Ⅰ)所示的结构式：
式(Ⅰ)中，M1代表源自不饱和单体的第一结构单元，m代表所述M1的聚合度，P1独立地选自结晶型热塑性树脂。
其中，上述改性聚合物中可以包含一种第一结构单元，或者包含多种不同结构的第一结构单元。此外，位于上述改性聚合物的分子链末端的两个封端基团P1可以是同种或不同种结晶型热塑性树脂。本申请实施方式中，上述式(Ⅰ)中两个P1优选是相同的。
本申请实施方式中，所述结晶型热塑性树脂包括间规聚苯乙烯(sPS)、聚四氟乙烯(PTFE)、聚偏氟乙烯(PVDF)、全氟烷氧基乙烯基醚聚合物、聚苯硫醚(Polyphenylene sulfide，简写为PPS)、聚醚醚酮、液晶聚合物中的一种或多种，但不限于此。在一些实施方式中，所述结晶型热塑性树脂包括sPS、PTFE、聚苯硫醚、液晶聚合物中的一种或多种。这4类树脂具有良好的耐热性和低介电性能，更适合制备PCB板。其中，聚苯硫醚的熔点在280℃左右，介电损耗因子Df可在0.002左右；PTFE的介电损耗因子Df可在0.005-0.0008左右。液晶聚合物的介电损耗在0.0006～0.002之间，示例性的液晶聚合物可以是Ⅰ型、Ⅱ型，对应的耐热性热变形温度分别为300℃以上、240～280℃。
本申请中，不饱和单体的分子结构中具有碳碳双键、碳碳叁键等不饱和键，以在制备上述预发泡材料时展现一定的聚合反应活性。本申请实施方式中，所述不饱和单体的分子结构中具有碳碳双键。其中，所述不饱和单体可以包括苯乙烯、马来酸酐、季戊四醇三丙烯酸酯、甲基丙烯酸酯、甲基丙烯酸缩水甘油酯、丙烯酸乙酯中的一种或多种，但不限于此。源自这些单体的结构单元有助于提升上述改性聚合物的熔体强度，进而可有效缓解通过上述预发泡材料经发泡得到的发泡材料发生分层和泡孔多是开孔的问题，同时对改性聚合物的介电性能影响较小。
本申请实施方式中，所述改性聚合物通过以下重量份数的各原料反应得到：结晶型热塑性树脂基体100份，不饱和单体0.1-5份，引发剂0.1-5份。
在一定温度下，引发剂可以致使结晶型热塑性树脂的分子链上产生自由基以作为反应位点，引发不饱和单体的聚合反应，从而制得具有上述结构的改性聚合物。从另一个角度看，引发剂和不饱和单体的引入，使结晶型热塑性树脂发生了微交联，破坏了其立构规整度，因此改性聚合物的熔程变宽，且分子缠绕增多，粘性增大、松弛时间变长。可以理解地，在制备该改性聚合物时，应先将引发剂与结晶型热塑性树脂基体混合，之后再加入不饱和单体，以避免结晶型热塑性树脂基体、不饱和单体、引发剂同时加入时，活性高的不饱和单体先在引发剂作用下发生聚合反应而不被结晶型热塑性树脂封端。此外，不饱和单体的加入量较少，其存在不会明显影响通过上述结晶型热塑性树脂封端的改性聚合物的低介电性能，也不会引起改性聚合物的微交联过大而影响成型加工性能。引发剂的较少加入量也有助于降低了不饱和单体发生自聚合的概率。
以结晶型热塑性树脂具体为sPS为例，制备上述改性聚合物的反应式可以如下所示：
本申请中，上述引发剂可以是有机过氧化合物类引发剂，其可以热分解使结晶型热塑性树脂的分子链上产生自由基作为反应位点。其中，所述引发剂可以包括过氧化二异丙苯(Dicumyl peroxide，简写为DCP)、二(叔丁基过氧化异丙基)苯、2,5-二甲基-2,5-双(叔丁基过氧)己烷、2-(叔丁基过氧化异丙基)苯、过氧化丁酮、过氧化二苯甲酰、过氧化十二酰中的一种或者多种，但不限于此。
本申请实施方式中，所述预发泡材料中还含有抗氧化剂。抗氧化剂的存在可在该预发泡材料的造粒过程中，提升上述改性聚合物的抗氧化性，避免其受热、氧而老化降解，失去使用价值。其中，所述抗氧化剂可以具体包括抗氧剂1010(化学名为:四[β-(3，5-二叔丁基-4-羟基苯基)丙酸]季戊四醇酯)、抗氧剂168(化学名为：三[2.4-二叔丁基苯基]亚磷酸酯)、抗氧剂1790等中的一种或多种，但不限于此。本申请实施方式中，预发泡材料中，抗氧化剂的质量可以是所述改性聚合物质量的0.09wt％-1wt％，例如具体是0.1wt％、0.3wt％、0.5wt％、0.6wt％或0.9wt％等。
本申请实施方式中，所述改性聚合物或所述预发泡材料基于差示扫描量热法(Differential Scanning Calorimetry，简写为DSC)在10℃/分钟的加热速率下的熔程在15℃以上，熔点在270℃以上。该改性聚合物或预发泡材料的熔程较宽，可降低其发泡过程中对发泡温度的精密控制难度；该改性聚合物或预发泡材料的熔点较高，采用其制成的预发泡材料的耐热性较好，适合用到对耐高温性要求高的PCB板中。在一些实施方式中，所述改性聚合物或所述预发泡材料的熔程在20℃以上，甚至在25℃以上。
本申请实施例还提供了上述预发泡材料的制备方法，包括以下步骤：
先将结晶型热塑性树脂与引发剂进行熔融共混，之后加入不饱和单体进行熔融共混，制得含改性聚合物的预发泡材料；其中，在所述引发剂的作用下，所述结晶型热塑性树脂能将所述不饱和单体发生聚合反应得到的聚合物的末端封端，而得到所述改性聚合物。
其中，上述制备方法中，先将引发剂与结晶型热塑性树脂基体熔融共混，之后再加入不饱和单体，这样有利于在结晶型热塑性树脂的分子链上产生自由基以作为反应位点，以引发不饱和单体的聚合反应，从而制得具有上述结构特性和物化特性的改性聚合物，避免结晶型热塑性树脂基体、不饱和单体、引发剂同时加入引起活性高的不饱和单体在引发剂作用下发生聚合反应而不被结晶型热塑性树脂封端。因此，上述特定的加料顺序可保证上述改性聚合物的得率较高，且预发泡材料的熔程较宽。
本申请一些实施方式中，在加入引发剂进行熔融共混约20-60s后，再加入不饱和单体进行述熔融共混。熔融共混的总时间可以是3-30min，例如5-20min，进一步可以是5-10min。其中，熔融共混的温度可以是270-300℃，例如是275、280、285、290、295℃。
本申请实施方式中，基于100重量份的所述结晶型热塑性树脂，所述引发剂的重量份为0.1-5份，所述不饱和单体的重量份是0.1-5份。引发剂和不饱和单体相较于结晶型热塑性树脂的加入量较低，这样有利于保证所得产物中上述改性聚合物的得率较高，副产物(如不饱和单体的聚合物)较少。特别地，较低用量的不饱和单体不会明显影响通过上述改性聚合物的低介电性能、成型加工性能(如不会使改性聚合物变成热固性树脂，无法注塑加工等)，同时又能提升改性聚合物的熔体强度，降低预发泡材料在发泡时发生分层和泡孔多是开孔的概率。
其中，基于100重量份的结晶型热塑性树脂，引发剂的重量份可以是0.2份、0.4份、0.5份、0.6份、0.8份、1份、1.5份、2份、3份或4份等；在一些实施方式中，引发剂的重量份为0.2-2份。基于100重量份的结晶型热塑性树脂，不饱和单体的重量份可以是0.2份、0.4份、0.5份、0.6份、0.8份、1份、1.5份、2份、3份、4份或4.5份等；在一些实施方式中，不饱和单体的重量份为0.2-4份，进一步可以是0.2-2份。
本申请一些实施方式中，在制备上述预发泡材料时，还采用了抗氧化剂。该抗氧化剂可以全部随结晶型热塑性树脂与引发剂一起加入；或者全部随不饱和单体加入；或者一部分随结晶型热塑性树脂与引发剂一起加入，另一部分随不饱和单体加入。其中，基于100重量份的所述结晶型热塑性树脂，所述引发剂的重量份为0.1-1份，例如0.2份、0.5份、0.6份、0.8份或0.9份等。抗氧化剂的作用如本申请前文所述，这里不再赘述。
此外，本申请其他实施方式中，在制备上述预发泡材料时，还可以加入其他助剂，且所述其他助剂不会对预发泡材料的发泡性能和发泡后的泡孔结构产生不利的影响。其中，所述其他助剂包括但不限于：爽滑剂、抗静电剂、防粘剂、增塑剂、阻燃剂等中的至少一种。
本申请中，上述熔融共混可以在混炼设备中进行，其中混炼设备可以提供剪切、混合、加热及可选的造粒、物料输送的设备，示例性地，混炼设备可以是熔融挤出机、哈克密炼机或双棍开炼机等，但不限于此。相应地，所述熔融共混的方式可以是挤出熔融共混、哈克密炼熔融共混或双棍熔融共混等。其中，挤出熔融共混和哈克密炼熔融共混属于密闭式熔融共混，双棍熔融共混是开放式熔融共混。
具体地，在采用熔融挤出机作为混炼设备时，上述结晶型热塑性树脂、引发剂、不饱和单体可在挤出机中加热熔融，挤出机的螺杆以一定速率转动，带动熔融态的混合物料不断被挤压、混合、反应，反应后的物料可从挤出机的模头挤出成料条，并借助旋转刀片将料条切成粒状，得到粒状的上述预发泡材料。而在采用哈克密炼机作为混炼设备时，上述结晶型热塑性树脂、引发剂、不饱和单体可在密炼机中加热熔融，依靠密炼机中的转子运动进行剪切，捏合，反应，反应后物料通过剪刀等辅助设备制备粒状，得到上述预发泡材料。而在采用双棍开炼机作为混炼设备时，上述结晶型热塑性树脂、引发剂、不饱和单体可在双棍开炼机中加热熔融，双棍开炼机的双棍以一定速率相向转动，带动熔融态的混合物料不断被挤压、混合、反应，反应后的物料是片状样品，可借助剪刀等辅助设备制备粒状，得到上述预发泡材料。
如本申请前文所述，由于上述改性聚合物的立体结构规整度较低，在含该改性聚合物的物料造粒成预发泡材料时，在造粒腔内表层的改性聚合物不易沿着模具进行取向排布，因此所得预发泡材料的表层和内层中改性聚合物的排布情况无明显差别，利于该预发泡材料经发泡得到不易分层的发泡材料。
本申请中，对上述预发泡材料的形状没有特别限定，可以是圆柱状、球状、椭球状、条状、棒状、块状、片状等相对小的尺寸。本申请一些实施方式中，所述预发泡材料为碎片状，在采用该预发泡材料进行发泡之前，可先将其成型为具有一定形状的待发泡制品，例如通过热压法转变成片材状待发泡制品，之后再采用该片材品直接进行发泡处理。
本申请上述提供的预发泡材料的制备方法，操作简单，预发泡材料中所含改性聚合物的结构新颖，立体结构的规整度较低，其熔程宽、熔体强度大，利于该预发泡材料顺利发泡制得不易分层的发泡材料，并提升其闭孔率、机械强度等。
相应地，本申请实施例还提供了一种发泡用原料，可用于制备上述预发泡材料，所述发泡用原料包括A组分和B组分，其中，所述A组分包括结晶型热塑性树脂及引发剂，所述B组分包括不饱和单体；其中，所述A组分和B组分在熔融共混时，在所述引发剂的作用下，所述结晶型热塑性树脂能将所述不饱和单体聚合得到的聚合物的末端封端。
其中，A组分和B组分分开放置，在使用该发泡用原料制备上述预发泡材料时，可先将A组分转变为熔融态，之后加入B组分，经熔融共混反应，制得含改性聚合物的预发泡材料。本申请中，对上述发泡用原料转变为预发泡材料的成型方式不做限定，可以是挤出成型、注塑成型、压缩成型、吹塑成型、压铸成型、真空成型等中的一种或多种。
如本申请前文所述，基于100重量份的所述结晶型热塑性树脂，所述引发剂的重量份为0.1-5份，所述不饱和单体的重量份是0.1-5份。本申请一些实施方式中，所述A组分和/或B组分中还包含抗氧化剂或其他助剂。其中，基于100重量份的结晶型热塑性树脂，所述抗氧化剂的重量份为0.1-1份。
本申请实施例还提供了一种发泡材料，所述发泡材料通过如本申请实施例前文所述的预发泡材料发泡得到，或者通过本申请实施例前文所述的发泡用原料制备得到。相应地，所述发泡材料中含有上述改性聚合物。
本申请中，发泡材料可以直接采用上述预发泡材料发泡得到，或者可以先将预发泡材料加工成与所述发泡材料形状对应的待发泡制品，然后通过对该待发泡制品进行发泡得到。
本申请一些实施方式中，所述发泡具体是超临界发泡。示例性地，所述发泡材料的制备过程包括：
S1，将所述预发泡材料成型为待发泡制品；
S2，对所述待发泡制品进行超临界发泡，得到发泡材料。
步骤S1中，所述预发泡材料成型为待发泡制品可以在加热下进行，以使预发泡材料熔融一体化，例如通过热压法转变成具有一定形状的待发泡制品。其中，所述待发泡制品与所需发泡材料的形状对应，二者的厚度可不同，可以理解地，发泡材料的厚度大于待发泡制品。
步骤S2中的超临界发泡的过程，可具体包括以下步骤：
S21，将所述待发泡制品放置在能够承受高压高温的发泡容器中，将所述发泡容器加热至预设温度；
S22，将超临界发泡剂引入到所述发泡容器中，使所述发泡容器内的压力达到预设压力，以浸渍所述待发泡制品；
S23，释放所述发泡容器内的压力，以使所述待发泡制品发泡，形成发泡材料。
本申请实施方式中，所述超临界发泡剂包括二氧化碳(CO2，临界温度为31.1℃、临界压力为7.38MPa)、氮气(N2，临界温度为-147℃、临界压力为3.39MPa)或其组合等。在一些实施方式中，步骤S22中还将共发泡剂引入到所述发泡容器中。其中，共发泡剂可以是乙醇、丙醇、异丙醇、丙酮、乙酸乙酯中的一种或多种。共发泡剂的存在可增加待发泡制品对超临界发泡剂的吸收。可以理解地，所述超临界发泡剂、共发泡剂应当对所述待发泡制品是惰性的。
步骤S21中，所述预设温度可以根据超临界发泡剂及上述改性聚合物的熔点进行设定。预设温度应高于所述超临界发泡剂的临界温度，以使发泡剂处于超临界状态。相应地，步骤S22中，在将超临界发泡剂引入到所述发泡容器中，应使所述发泡容器内达到的预设压力保持高于超临界发泡剂的临界压力，以使发泡剂处于超临界状态，便于扩散进入待发泡制品中，在其中达到较高的溶解度。其中，浸渍过程是保持发泡容器内的环境在所述预设温度及预设压力下一段时间，以使待发泡制品吸收一定量的超临界发泡剂。在一些实施例中，当所述超临界发泡剂为CO2时，所述预设温度可以在270-300℃的范围内，例如270、275、280、285、290℃等；步骤S22中所述发泡容器的预设压力可以在8-20MPa的范围内，例如为9、10、12、15、18或20MPa等。
步骤S23中，待所述待发泡制品被超临界发泡剂浸渍饱和后(或说超临界发泡剂达到溶解平衡后)，可以一次释放或分段释放所述发泡容器内的压力，该过程也可称为“卸压”，即，使发泡容器内的压力降低，例如可降至大气压。在卸压过程中，会在待发泡制品中产生大量的泡孔核，泡孔核的不断生长，获得具有泡孔的发泡材料。在一些实施方式中，以0.8-10MPa/s的速率使所述发泡容器内的压力降至大气压。可选地，卸压所用的时间可以是2-10s。
上述超临界发泡过程可以在发泡装置中进行。参见图2，发泡装置200可以包括：
发泡容器21，用于放置待发泡制品201；
温控系统22，用于对发泡容器21进行加热，以达到预设温度；
高压输送系统23，用于向发泡容器21内输送超临界发泡剂，以使发泡容器21的压力达到预设压力；
释压系统24，用于在所述超临界发泡剂浸渍待发泡制品201饱和后，释放发泡容器21内的压力，以使待发泡制品201发泡、得到发泡材料。
本申请实施方式中，温控系统22包括加热组件221和温度传感器222，其中，加热组件221用于向发泡容器21提供热源，使发泡容器21内的温度达到预设值，温度传感器222用于监测发泡容器21内的温度。发泡容器21可以具体是发泡模具。
本申请实施方式中，高压输送系统23包括流体源231(通常是气源，如CO2、N2等)、泵232、进气管道233和进气阀234，其中，泵232管道连接在流体源231与发泡容器21之间；发泡容器21的腔体与泵232通过进气管道233连通，该进气管道233上设有进气阀234。进气阀234可调控输送给发泡容器21的超临界发泡剂的流量、发泡容器21的压力等。此外，为便于监控发泡容器21内的压力，发泡容器21上还设有压力传感器202。本申请中，进气管道233的数目、进气阀234、流体源231的数目等可以是一个或多个，具体可根据超临界发泡剂的种类、是否使用共发泡剂等决定。
本申请实施方式中，释压系统24包括与发泡容器21连通的释压通道241，该释压通道241上设有释压阀242，以在需要时释放发泡容器21内的压力。可以理解地，发泡容器21上设有进气口I1、出气口O1，进气管道233通过进气口I1与发泡容器21连通，释压通道241通过出气口O1与发泡容器21连通。当然，本申请其他实施方式中，发泡容器21上也可以直接设有释压阀。
本申请一些实施方式中，发泡装置200还包括液压系统25，用于提供将放置有待发泡制品201的发泡容器21关闭的压力，以使发泡容器21达到封闭状态，便于对其进行加热、输送流体等。可以理解地，该液压系统25与发泡容器21的腔体连通。
采用上述发泡装置对含有前述改性聚合物的待发泡制品进行发泡，可以得到泡孔均匀、闭孔率高、不 易分层的发泡材料。
本申请中，对上述发泡材料的形状不做限定，例如可以是片材状、块状、棒状、管状、柱状、或其他形状等。本申请一些实施方式中，当上述发泡材料用于PCB板中时，如具体用作图1中的介质层片材11，该发泡材料可以是片材状，也可将该发泡材料称为“发泡片”。
本申请中，发泡材料具有多孔结构。其中，该发泡材料中的泡孔大部分是闭孔。本申请实施方式中，所述发泡材料的泡孔闭孔率(也可称为“封闭泡孔率”)在50％以上，例如在55％以上、60％以上，甚至80％以上。较高的泡孔闭孔率利于保证发泡材料具有优良的抗吸水性。具体地，该泡孔闭孔率可以为50％、52％、55％、58％、60％、65％、70％、75％、80％、85％、90％、99％或100％等。在一些实施方式中，所述发泡材料的泡孔闭孔率可以是50％-80％，进一步可以是50％-60％。其中，可以根据GB/T 10799-2008标准测得发泡材料的泡孔闭孔率。
本申请实施方式中，所述发泡材料在温度为23℃、相对湿度为50％的环境下放置在水中24小后的吸水率在1％以下。较低的吸水率有利于提升该发泡材料的使用寿命，特别是在潮湿环境下的使用寿命。在一些实施方式中，发泡材料的上述吸水率在0.8％以下，有些情况下可在0.7％以下，甚至在0.6％以下等。
其中，上述吸水率采用GB_T 8810-2005进行测试。先制备尺寸为10mm×10mm的样品，在100℃烘干2小时，称量其重量。然后将该样品放置在水中，并于温度为23℃±2℃、相对湿度为50％±5％的环境下放置24小时，之后取出样品，用滤纸擦干表面的水分后立即称量，通过样品放置在水中前后的重量变化来反映吸水率。
本申请实施方式中，所述发泡材料的平均泡孔尺寸在5-100μm的范围内。该平均泡孔尺寸可指各泡孔的开口横截面的最大宽度的平均值。该发泡材料的平均泡孔尺寸较小，当该上述发泡材料用作PCB板中层压板10的介质层片材11时，借助在该泡孔内镀的金属膜(如铜膜)可以实现层压板10中上下金属箔上部分线路的导通，利于缩短线路的导通路程。本申请一些实施方式中，所述发泡材料的平均泡孔直径为10μm-60μm。
本申请实施方式中，所述发泡材料的密度在1g/cm3以下。可按照GB/T6343-2009标准测试多孔发泡体的表观密度。较低密度的发泡材料，有利于实现使用其的器件的轻量化。特别地，当该发泡材料用到PCB板中，利于PCB板的运输和安装。在一些实施方式中，所述发泡材料的密度为0.1-0.8g/cm3；在另一些实施方式中，所述发泡材料的密度为0.2-0.6g/cm3，甚至为0.2-0.4g/cm3。
本申请实施方式中，基于谐振腔法测得所述发泡材料在频率为10GHz的电磁波下的介电常数Dk在2.0以下，介电损耗Df在0.0015以下。由此可以获知该发泡材料的介电性能较优良，采用其制作PCB板，其对信号的延迟、衰减影响均越小，可以使PCB板满足高频高速的通讯需求。其中，介电常数Dk和介电损耗Df可根据分离介电谐振器(splite post dielectric resonator，简写为SPDR)法测得，测试频率为10GHz。
本申请实施例还提供了上述预发泡材料、上述发泡材料、上述发泡用原料在制备印刷电路板(具体用作印刷电路板的低介电材料)、缓冲材料、减震材料、隔热材料、吸音材料中等轻量化材料中的应用。其中，印刷电路板、缓冲材料、隔热材料、吸音材料等可以通过发泡法制得。需要说明的是，本申请提到的预发泡材料、发泡材料、发泡用原料的应用可不仅局限于制作印刷电路板、缓冲材料、减震材料等，还可以根据需要用在其他应用场景。
其中，上述预发泡材料、发泡材料、发泡用原料用于制备印刷电路板时，具体可用作印刷电路板中的层压板中的介电材料。此外，当它们用来制备缓冲材料时，可以具体作为电子组件中相邻部件或相邻层的缓冲结构。
相应地，本申请实施例提供了一种层压板，该层压板包括本申请实施例上述的发泡材料。采用该层压板可制得印刷电路板。
其中，该层压板的结构如本申请前述图1所述，层压板10包括介质层片材11及位于介质层片材11表面的金属箔12，介质层片材11可以是本申请实施例上述的发泡材料。在有些情况下，该层压板也可以称为“覆金属层叠板”。该层压板中的介质层片材具有较低介电性能、较低吸水率及较轻密度，适合制作轻质、高频高速的印刷电路板。
其中，可以在介质层片材11的一侧表面或相对两侧表面上放置金属箔12。金属箔12可以是铜箔、铝箔、镍箔、银箔或其合金箔等。其中，以铜箔较为常见，带有铜箔的层压板10可称为“覆铜板”。上述层压板10可以通过以下方法制得：取上述发泡材料作介质层片材11，在其一侧表面或相对两侧表面上放置金属箔12，经热压压合，得到层压板10。
本申请实施例还提供了一种印刷电路板，所述印刷电路板包括至少一个本申请实施例上述的层压板。
其中，印刷电路板可以包括一个上述层压板，或者包括至少两个层压板的叠合结构。多个层压板可通过热压实现叠合。
此外，上述层压板10的金属箔12上还设置有线路。具体可通过在层压板10的金属箔12表面贴合感光膜、并在线路掩膜版下对感光膜进行曝光、显影，得到图案化的感光层，以其为遮罩对铜箔进行蚀刻，之后去除感光膜，得到具有线路图案的层压板。之后可将多个具有线路图案的层压板10进行热压压合，得到层叠板。通过对层叠板进行打孔，并对孔壁进行铜化学沉淀，可实现不同层压板之间的信号导通，最后可通过该层叠板的外层线路图案刷上阻焊层，并进行表处理，可得到完整的印刷电路板。
本申请实施例还提供了一种电子组件，该电子组件包括本申请实施例上述的印刷电路板。
其中，该电子组件除了包括上述印刷电路板外，还可以包括附接在印刷电路上的各种电子元器件(例如各种芯片、晶体管、LED器件、阻容感元件(如电阻、电容、电感)等)，以及包覆它们的塑封结构。
本申请实施例还提供了一种电子设备，该电子设备包括本申请实施例上述的电子组件或本申请实施例上述的印刷电路板。
采用本申请实施例的电子组件或印刷电路板，可以改善电子设备的性能。其中，该电子设备可以是手机、平板电脑、笔记本电脑、台式电脑、可穿戴设备(如智能手表、智能手环)、便携机、基站天线、汽车雷达等产品。
本申请实施例还提供了一种改性聚合物，该改性聚合物具有式(Ⅰ)所示的结构式：
式(Ⅰ)中，M1代表源自不饱和单体的第一结构单元，m代表所述M1的聚合度，P1独立地选自结晶型热塑性树脂。其中，关于所述不饱和单体、结晶型热塑性树脂的介绍如本申请前文所述。
本申请实施方式中，所述改性聚合物基于差示扫描量热法在10℃/分钟的加热速率下的熔程在15℃以上，熔点在270℃以上。该改性聚合物适合用作预发泡材料的制备原料，制得闭孔率高、不易分层的发泡材料。
本申请实施例还提供了本申请实施例上述改性聚合物在制备发泡材料、塑封材料、胶黏剂、树脂组合物中的应用。其中，上述改性聚合物可用作制备上述发泡用原料、上述预发泡材料、待发泡制品、发泡材料等。此外，上述改性聚合物还可以用作塑封材料、胶黏剂等，其可以通过注塑、注射、模压、浇筑或涂覆等方式制成塑封材料、胶黏剂等。
本申请中，“至少一个”是指一个或者多个，“多个”是指两个或两个以上。“以下至少一项(个)”或其类似表达，是指的这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，“a,b或c中的至少一项(个)”，或，“a,b和c中的至少一项(个)”，均可以表示：a,b,c,a-b(即a和b),a-c,b-c,或a-b-c，其中a,b,c分别可以是单个，也可以是多个。
本申请中，“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B的情况，其中A,B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。
此外，本申请在提及某一参数范围是“在c以下”或在“d以上”时，皆包含本数。例如，当某一参数在c以下时，意值包含本数c及比c小的任意值。此外，当某一参数是在e至f的范围内时，也包含本数，即指包含端点值e、端点值f，以及介于e与f之间的任意值。
下面分多个具体实施例对本申请实施例进行进一步的说明。其中，本申请实施例不限定于以下的具体实施例。
实施例1
预发泡材料(具体是发泡用粒子)的制备：
将100重量份的间规聚苯乙烯(sPS)树脂粒子、0.5重量份的引发剂—过氧化二异丙苯(DCP)、0.25重量份的抗氧剂1010及0.25重量份的抗氧剂168搅拌均匀后加入到哈克密炼机中进行熔融共混，其中，哈克密炼机的转速为50rpm，熔融共混的温度为285℃，30秒后再向该哈克密炼机中加入0.5重量份的含双键单体—苯乙烯，继续进行熔融共混，总的熔融共混时间为5min。之后将所得样品从哈克密炼机中取出，并用剪刀切成长宽尺寸为3mm×3mm的碎片，该碎片即为所需发泡用粒子。该发泡用粒子中含有以下改性聚合物P1，其通过在引发剂的作用下，sPS树脂能将苯乙烯单体发生聚合反应得到的聚合物的末端封端得 到。
其中，上述熔融共混过程中涉及到的反应式如下：
其中，测得含上述改性聚合物P1的发泡用粒子的熔点为273℃，熔程为25℃，松弛时间约为33s。
发泡材料的制备：
(1)将实施例1的上述发泡用粒子放入直径为50mm的圆片的模具中，在平板硫化机上进行压合，压合温度为285℃，压力为10MPa，压合时间为5min。压合结束后从模具中取出，得到直径为50mm的含改进聚合物P1的圆片，作为待发泡制品。
(2)将上述待发泡制品放置在高压釜中，并将该高压釜加热至所需发泡温度280℃；之后向釜中通入CO2吹扫掉釜内的空气，重复吹扫三次，然后向釜内通入CO2至釜内压力达到14MPa，在280℃下使CO2浸渍待发泡制品40min，以达到吸收饱和；随后通过高压釜上接出的管道上设置的高压球阀进行快速卸压，在6秒内使釜内卸至常压以使待发泡制品发泡，最后从高压釜中取出所得发泡材料，其呈片材状。
图3为本申请实施例1所得发泡材料的扫描电子显微镜(Scanning Electron Microscope，SEM)照片。从图3可以获知，该发泡材料的泡孔尺寸较均匀，且大部分为闭孔，据此可计算得到平均泡孔尺寸为30μm。
其中，根据本申请前文记载的方法，测得实施例1所得发泡材料的密度为0.38g/cm3，泡孔闭孔率为50.4％，吸水率为0.54％，弯曲强度为3.5MPa；该发泡材料在频率为10GHz的电磁波下的介电常数Dk为1.7、介电损耗Df为0.0006。
实施例2
实施例2与实施例1的区别在于：在制备发泡用粒子时，采用0.5重量份的季戊四醇三丙烯酸酯(PETA)来替换实施例1用的苯乙烯单体。这样，实施例2的发泡用粒子中就含有以下改性聚合物P2，P2通过在引发剂DCP的作用下，sPS树脂将PETA单体发生聚合反应得到的聚合物的末端封端得到。
其中，实施例2在制备发泡用粒子时，涉及改性聚合物P2的合成反应式如下：
测得含上述改性聚合物P2的发泡用粒子的熔点为272℃，熔程为20℃，松弛时间约为22s。
根据实施例1记载的方法，将实施例2得到的发泡用粒子制备成发泡材料。
其中，图4为本申请实施例2所得发泡材料的SEM照片。从图4可以获知，该发泡材料的泡孔尺寸较均匀，且大部分为闭孔，据此可计算得到平均泡孔尺寸为40μm。
此外，测得实施例2所得发泡材料的密度为0.36g/cm3，泡孔闭孔率为56.3％，发泡材料的吸水率为0.59％，弯曲强度为3.3MPa；该发泡材料在频率为10GHz的电磁波下的介电常数Dk为1.5、介电损耗Df为0.0005。
实施例3
实施例3与实施例1的区别在于：在制备发泡用粒子时，采用0.5重量份的马来酸酐(MA)来替换实施例1用的苯乙烯单体，用引发剂BPO代替实施例1用的DCP。这样，实施例3的发泡用粒子中含有以下改性聚合物P3，P3通过在引发剂BPO的作用下，sPS树脂将MA单体发生聚合反应得到的聚合物的末端封端得到。
其中，实施例3在制备发泡用粒子时，涉及改性聚合物P3的合成反应式如下：
测得含上述改性聚合物P3的发泡用粒子的熔点为274℃，熔程为28℃，松弛时间约为36s。
根据实施例1记载的方法，将实施例3得到的发泡用粒子制备成发泡材料。
其中，测得实施例3所得发泡材料的平均泡孔尺寸为50μm，泡孔闭孔率为54.5％，发泡材料的密度为0.32g/cm3，吸水率为0.61％，弯曲强度为3.8MPa；该发泡材料在频率为10GHz的电磁波下的介电常数Dk为1.5、介电损耗Df为0.0005。
实施例4
实施例4与实施例1的区别在于：在制备发泡材料时，将实施例1中发泡用粒子成型得到的待发泡制品在发泡温度为275℃下被CO2浸渍40min。
测得实施例4所得发泡材料的平均泡孔尺寸为5μm，泡孔闭孔率为75％，发泡材料的密度为0.7g/cm3，吸水率为0.15％，弯曲强度为10MPa；该发泡材料在频率为10GHz的电磁波下的介电常数Dk为1.9、介电损耗Df为0.0006。
实施例5
实施例5与实施例2的区别在于：在制备发泡材料时，将实施例2的发泡用粒子成型的待发泡制品在发泡温度为275℃下被CO2浸渍40min。
测得实施例5所得发泡材料的平均泡孔尺寸为8μm，泡孔闭孔率为65％，发泡材料的密度为0.65g/cm3，吸水率为0.35％，弯曲强度为7.5MPa；该发泡材料在频率为10GHz的电磁波下的介电常数Dk为1.8、介电损耗Df为0.0006。
实施例6
实施例6与实施例1的区别在于：在制备发泡用粒子时，sPS、引发剂、苯乙烯单体的重量比为100：0.1：0.2。
测得实施例6所得发泡用粒子的熔点为274℃，熔程为27℃，松弛时间约为35s。
根据实施例1记载的方法，将实施例6得到的发泡用粒子制备成发泡材料。其中，测得实施例6所得发泡材料的平均泡孔尺寸为25μm，泡孔闭孔率为59％，发泡材料的密度为0.35g/cm3，吸水率为0.57％，弯曲强度为3.4MPa；该发泡材料在频率为10GHz的电磁波下的介电常数Dk为1.7、介电损耗Df为0.0007。
为突出本申请实施例的有益效果，本申请还设置以下对比例1-3。
对比例1
发泡用粒子的制备：在铝箔袋中，加入100重量份的sPS树脂粒子、0.25重量份的抗氧剂1010及0.25重量份的抗氧剂168，搅拌均匀后加入哈克密炼机中进行熔融共混密炼(哈克密炼机的转速、熔融共混的温度及总时间同实施例1)，熔融共混结束后，从哈克密炼机中取出所得样品，并用剪刀切成长宽尺寸为3mm×3mm的碎片，该碎片即为所需发泡用粒子。
发泡材料的制备：将对比例1的上述发泡用粒子按实施例1记载的方式加工成发泡材料，其与实施例1的不同之处在于：在发泡温度为265℃下浸渍40min。
其中，测得对比例1所得发泡用粒子的熔点为271℃，熔程为8.6℃，松弛时间约为9s。
测得对比例1所得发泡材料的泡孔大部为开孔，且发泡材料出现分层现象(参见图5)。其中泡孔的闭孔率低至20％。该发泡材料的密度为0.44g/cm3，吸水率高达13.84％，弯曲强度仅为2MPa；该发泡材料在频率为10GHz的电磁波下的介电常数Dk为1.5、介电损耗Df为0.0004。
对比例2—针对实施例1设置
对比例2与实施例1的区别在于：在制备发泡用粒子时，同时将sPS、引发剂DCP、苯乙烯单体加入到哈克密炼机中进行熔融共混。
其中，对比例2所得发泡用粒子的熔点为273℃，熔程为13.9℃，松弛时间约21为s。此外，测得对比例2所得发泡材料的泡孔大部分为开孔，泡孔闭孔率仅为20％，发泡材料的密度为0.40g/cm3，吸水率为14.60％，弯曲强度为1.7MPa；该发泡材料在频率为10GHz的电磁波下的介电常数Dk为1.6、介电损耗Df为0.0006。
对比例3—针对实施例2设置
对比例3与实施例2的区别在于：在制备发泡用粒子时，同时将sPS、引发剂DCP、季戊四醇三丙烯酸酯(PETA)加入到哈克密炼机中进行熔融共混。
其中，对比例3所得发泡用粒子的熔点为273℃，熔程为14.5℃，松弛时间约为21s。此外，测得对比例3所得发泡材料的泡孔大部分为开孔，泡孔闭孔率仅为20％，发泡材料的密度为0.47g/cm3，吸水率为13.10％，弯曲强度为2.2MPa；该发泡材料在频率为10GHz的电磁波下的介电常数Dk为1.7、介电损耗Df为0.0006。
通过本申请各实施例与对比例1的对比可以获知，含有本申请改性聚合物的发泡用粒子，其熔程明显高于对比例1，可提高到15℃以上，甚至可以在20℃以上；其松弛时间可以提高到30s以上。这表明本申请的发泡用粒子特别适合通过超临界发泡法发泡制得发泡材料，发泡过程的温度无需控制在特别窄的范围，降低了温控难度；且发泡用粒子的较长松弛时间利于提升所得发泡材料的泡孔均匀性。
此外，从对比例2与实施例1的对比、对比例3与实施例2的对比可以获知，当将结晶型热塑性树脂(如sPS)与引发剂、不饱和单体同时进行熔融共混而非先将结晶型热塑性树脂与引发剂熔融混合后再加入不饱和单体时，对比例所得发泡用粒子中并未制得本申请结构新型的改性聚合物，因此发泡用粒子的熔程仍较窄，经其发泡得到的发泡材料的开孔率较高。

Claims (28)

  1. 一种预发泡材料，其特征在于，所述预发泡材料包括改性聚合物，其中，所述改性聚合物具有源自不饱和单体的第一结构单元，所述改性聚合物的分子链末端封端有结晶型热塑性树脂。
  2. 如权利要求1所述的预发泡材料，其特征在于，所述结晶型热塑性树脂包括间规聚苯乙烯、聚四氟乙烯、聚偏氟乙烯、全氟烷氧基乙烯基醚聚合物、聚苯硫醚、聚醚醚酮、液晶聚合物中的一种或多种。
  3. 如权利要求1或2所述的预发泡材料，其特征在于，所述不饱和单体包括苯乙烯、马来酸酐、季戊四醇三丙烯酸酯、甲基丙烯酸酯、甲基丙烯酸缩水甘油酯、丙烯酸乙酯中的一种或多种。
  4. 如权利要求1-3任一项所述的预发泡材料，其特征在于，所述改性聚合物具有式(Ⅰ)所示的结构式：
    式(Ⅰ)中，M1代表源自不饱和单体的第一结构单元，m代表所述M1的聚合度，P1独立地选自结晶型热塑性树脂。
  5. 如权利要求1-4任一项所述的预发泡材料，其特征在于，所述预发泡材料通过以下重量份数的各原料反应得到：结晶型热塑性树脂基体100份，不饱和单体0.1-5份，引发剂0.1-5份。
  6. 如权利要求5所述的预发泡材料，其特征在于，所述引发剂包括过氧化二异丙苯、二(叔丁基过氧化异丙基)苯、2,5-二甲基-2,5-双(叔丁基过氧)己烷、2-(叔丁基过氧化异丙基)苯、过氧化丁酮、过氧化二苯甲酰、过氧化十二酰中的一种或者多种。
  7. 如权利要求1-6任一项所述的预发泡材料，其特征在于，所述预发泡材料中还含有抗氧化剂。
  8. 如权利要求7所述的预发泡材料，其特征在于，所述抗氧化剂的质量是所述改性聚合物质量的0.09wt％-1wt％。
  9. 如权利要求1-8任一项所述的预发泡材料，其特征在于，所述预发泡材料基于差示扫描量热法在10℃/分钟的加热速率下的熔程在15℃以上，熔点在270℃以上。
  10. 一种发泡材料，其特征在于，所述发泡材料通过如权利要求1-9任一项所述的预发泡材料发泡得到。
  11. 如权利要求10所述的发泡材料，其特征在于，所述发泡材料中的泡孔大部分是闭孔。
  12. 如权利要求10或11所述的发泡材料，其特征在于，所述发泡材料的平均泡孔尺寸在5-100μm的范围内。
  13. 如权利要求10-12任一项所述的发泡材料，其特征在于，所述发泡材料在温度为23℃、相对湿度为50％的环境下放置在水中24小后的吸水率在1％以下。
  14. 如权利要求10-13任一项所述的发泡材料，其特征在于，所述发泡材料的密度在1g/cm3以下。
  15. 如权利要求10-14任一项所述的发泡材料，其特征在于，基于谐振腔法测得所述发泡材料在频率为10GHz的电磁波下的介电常数在2.0以下，介电损耗在0.0015以下。
  16. 一种预发泡材料的制备方法，其特征在于，包括以下步骤：
    先将结晶型热塑性树脂与引发剂进行熔融共混，之后加入不饱和单体进行熔融共混，制得含改性聚合物的预发泡材料；其中，在所述引发剂的作用下，所述结晶型热塑性树脂能将所述不饱和单体发生聚合反应得到的聚合物的末端封端而得到改性聚合物。
  17. 如权利要求16所述的制备方法，其特征在于，基于100重量份的所述结晶型热塑性树脂，所述引发剂的重量份为0.1-5份，所述不饱和单体的重量份是0.1-5份。
  18. 一种制备发泡材料的发泡装置，其特征在于，包括：
    发泡容器，用于放置待发泡制品，所述待发泡制品为如权利要求1-9任一项所述的预发泡材料或所述预发泡材料的成型品；
    温控系统，用于对所述发泡容器进行加热，以达到预设温度；
    高压输送系统，用于向所述发泡容器内输送超临界发泡剂，以使所述发泡容器的压力达到预设压力；
    释压系统，用于在所述超临界发泡剂浸渍所述待发泡制品饱和后，释放所述发泡容器内的压力，以使所述待发泡制品发泡，形成所述发泡材料。
  19. 一种发泡用原料，其特征在于，包括A组分和B组分，其中，所述A组分包括结晶型热塑性树脂及引发剂，所述B组分包括不饱和单体；其中，所述A组分和B组分在熔融共混时，在所述引发剂的 作用下，所述结晶型热塑性树脂能将所述不饱和单体聚合得到的聚合物的末端封端。
  20. 如权利要求1-9任一项所述的预发泡材料或权利要求10-15任一项所述的发泡材料、如权利要求19所述的发泡用原料在制备印刷电路板、缓冲材料、减震材料、隔热材料、吸音材料中的应用。
  21. 如权利要求1-9任一项所述的预发泡材料或如权利要求19所述的发泡用原料在制备发泡材料中的应用。
  22. 一种层压板，其特征在于，所述层压板包括介质层片材及位于所述介质层片材表面的金属箔，其中，所述介质层片材包括如权利要求10-15任一项所述的发泡材料。
  23. 一种印刷电路板，其特征在于，所述印刷电路板包括至少一个如权利要求22所述的层压板。
  24. 一种电子组件，其特征在于，所述电子组件包括权利要求23所述的印刷电路板。
  25. 一种电子设备，其特征在于，所述电子设备包括权利要求24所述的电子组件或权利要求23所述的印刷电路板。
  26. 一种改性聚合物，其特征在于，所述改性聚合物具有式(Ⅰ)所示的结构式：
    式(Ⅰ)中，M1代表源自不饱和单体的第一结构单元，m代表所述M1的聚合度，P1独立地选自结晶型热塑性树脂。
  27. 如权利要求26所述的改性聚合物，其特征在于，所述改性聚合物基于差示扫描量热法在10℃/分钟的加热速率下的熔程在15℃以上，熔点在270℃以上。
  28. 如权利要求26或27所述的改性聚合物在制备发泡材料、塑封材料、胶黏剂、树脂组合物中的应用。
PCT/CN2023/104368 2022-08-10 2023-06-30 预发泡材料及其制备方法和应用 WO2024032237A1 (zh)

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Publication number Priority date Publication date Assignee Title
US5670102A (en) * 1993-02-11 1997-09-23 Minnesota Mining And Manufacturing Company Method of making thermoplastic foamed articles using supercritical fluid
CN1402757A (zh) * 1999-12-28 2003-03-12 钟渊化学工业株式会社 可发泡的聚苯乙烯树脂粒子和由其生产的泡沫制品
WO2009065774A1 (en) * 2007-11-23 2009-05-28 Basf Se Grafting of ethylenically unsaturated monomers onto polymers in supercritical carbon dioxide
CN102911392A (zh) * 2012-10-22 2013-02-06 郑州大学 利用超临界流体co2制备辐射改性聚乳酸发泡材料的方法
CN107556513A (zh) * 2017-09-14 2018-01-09 四川大学 一种结晶型聚合物发泡粒子成型体及其制备方法
CN114479224A (zh) * 2020-10-23 2022-05-13 中国石油化工股份有限公司 热塑性树脂多孔发泡体及其制备方法与应用

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5670102A (en) * 1993-02-11 1997-09-23 Minnesota Mining And Manufacturing Company Method of making thermoplastic foamed articles using supercritical fluid
CN1402757A (zh) * 1999-12-28 2003-03-12 钟渊化学工业株式会社 可发泡的聚苯乙烯树脂粒子和由其生产的泡沫制品
WO2009065774A1 (en) * 2007-11-23 2009-05-28 Basf Se Grafting of ethylenically unsaturated monomers onto polymers in supercritical carbon dioxide
CN102911392A (zh) * 2012-10-22 2013-02-06 郑州大学 利用超临界流体co2制备辐射改性聚乳酸发泡材料的方法
CN107556513A (zh) * 2017-09-14 2018-01-09 四川大学 一种结晶型聚合物发泡粒子成型体及其制备方法
CN114479224A (zh) * 2020-10-23 2022-05-13 中国石油化工股份有限公司 热塑性树脂多孔发泡体及其制备方法与应用

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