JP2000238118A - Molded product and molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molded product which shows outstanding shape rigidity, impact and vibration absorption, sound and heat insulating properties, lightweight properties and dimensional stability, and a method for manufacturing the molded product. SOLUTION: This molding method is to bring a parison 20 into contact with the molding face of a mold 30 and supply gel or a gel precursor and a solvent into the internal space of the parison 20 to press these materials against the molding face of the mold 30 by the internal pressure. Further, after at least a part of the mixture of the gel or the gel precursor and the solvent is made to swell with the solvent and gelatinized, the mold 30 is opened to unload a molded product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polymer molded article having therein a solvent-swelled gel containing at least a part of a solvent, and a molding method thereof. Since the molded article of the present invention is excellent in shock absorption, shape rigidity, etc. and has good dimensional accuracy, vehicle exterior parts such as bumpers, fenders, door outer panels, instrument panels, glove boxes,
It can be suitably used for vehicle interior parts such as door trims, building materials such as wall materials, partition plates, flooring materials and the like. Further, the molding method of the present invention provides a method of molding the above-mentioned molded article by, for example, blow molding or injection molding, and also enables a shortening of a molding cycle.

[0002]

2. Description of the Related Art There is an application in which a resin molded product having excellent characteristics in one or more of shape rigidity, shock absorption, vibration absorption, sound insulation, heat insulation, light weight, etc. is desired. For example, Japanese Patent Application Laid-Open No. 53-119459 discloses that an inorganic room-temperature foaming agent is injected into a hollow portion of a thermoplastic resin which is blow-molded by blow molding or vacuum molding, and foamed and hardened to provide fireproof and heat insulating properties. There is described a molding method for obtaining an inorganic lightweight insulation molded article excellent in waterproofness and vibration resistance. Further, JP-A-2-261935 discloses that a thin film member made of a thermoplastic elastomer or a synthetic rubber having elasticity is formed into a hollow shape, and the hollow portion is filled with a liquid silicone gel, and then cured and sealed. A production method for obtaining a molded article having excellent cushioning properties is described. Also,
Japanese Patent Application Laid-Open No. 3-293113 discloses the production of a foaming agent-filled product in which a blowing agent is injected into a parison and cooled while the mold is clamped, and the foaming agent is reacted and solidified in blow molding. A method is described. Japanese Patent Publication No. 3-56905 also discloses that synthetic resin foamed particles are supplied and filled in a mold pressurized by a pressurized gas while compressing the gas with a gas having a pressure higher than the pressure in the mold, and then foamed by steam heating. A method of controlling the supply of foamed particles in accordance with pressure in a method of molding a foamed molded article by fusing particles is described.

[0003]

According to the method described in the above-mentioned publications, the molding time is prolonged due to foaming, and a special device for filling the liquid silicone rubber is required, so that the cost of the molded product increases. There's a problem. In addition, when filling is performed after molding a hollow molded article, if the thickness of the molded article is small, rigidity is not sufficient, so that the filling (filling) of a foaming agent or liquid silicone rubber changes the shape (shape). There is also a problem that a special mold is required to prevent this. An object of the present invention is to provide a polymer molded article having excellent characteristics in one or more of shape rigidity, shock absorption, vibration absorption, sound insulation, heat insulation, lightness, and the like. It is another object of the present invention to provide a polymer molded article having the above-mentioned characteristics and high dimensional accuracy. Another object of the present invention is to provide a method for producing a polymer molded article having the above-mentioned characteristics in a relatively short molding cycle with high productivity. It is another object of the present invention to provide a method for producing a polymer molded article having the above-mentioned characteristics with high productivity without using a special apparatus at the time of production.

[0004]

The invention according to claim 1 is a molded product obtained by supplying a gel or a gel precursor and a solvent to a hollow portion of a hollow polymer product which is constrained by a mold. According to the invention of claim 2, the gel or gel precursor supplied to the hollow portion absorbs at least a part of the solvent to form a solvent swelling gel and then releases the constraint of the mold to obtain the gel or gel precursor. It is a molded product. The invention according to claim 3 is the molded article according to claim 1 or 2, wherein the hollow polymer article restrained by the mold is obtained by blow molding. According to a fourth aspect of the present invention, the forming material of the hollow polymer is a thermoplastic polymer, and the forming material is pressed in a molten state against a cavity molding surface heated to a temperature equal to or higher than the Vicat softening temperature (T) ° C. of the thermoplastic polymer. The molded article according to any one of claims 1 to 3, wherein a hollow polymer article is obtained by performing the method. The invention of claim 5 is a molded article formed by bringing a polymer into contact with a cavity molding surface in a molten state, and supplying a gel or a gel precursor and a solvent into the inside of the polymer and pressing the polymer onto the cavity molding surface. The invention according to claim 6 is that the polymer is brought into contact with the molding surface of the mold in a molten state, and the gel or the gel precursor and the solvent are supplied to the inside or the internal space of the polymer and pressed against the molding surface of the mold, Alternatively, the method is a molding method of a molded article in which the mold is opened and the molded article is taken out after the gel precursor absorbs at least a part of the solvent to form a solvent-swelled gel. The method of supplying the inside can be used in the injection molding method. The method of supplying to the internal space can be used in the blow molding method.

The gel or the gel precursor and the solvent have fluidity at the time of supply, and after forming, form a solvent-swollen gel at least at the use temperature of the molded article. The molding method is preferably a blow molding method. A method of supplying a gel or a gel precursor and a solvent in a blow molding method will be described. Hereinafter, the gel or gel precursor is referred to as A, and the solvent is referred to as B. The method of supplying A and B is not particularly limited. For example, during the blow step for forming a hollow portion, A
And B (hereinafter referred to as "method A"), a method in which a hollow portion is formed and A and B are supplied therein (hereinafter referred to as "method B"), or both the a and b methods are used. Method (hereinafter referred to as "c method"). The preferred method is the b method. FIG. 4 shows an example of the method. In the illustrated example, exhaust is performed in order to supply A and B smoothly. However, suction may be performed instead of or in combination with exhaust to supply the gas smoothly. Examples of the method of supplying A and B in the method A, the method B, and the method C include the following methods. (1) Case 1: Method of mixing and supplying A and B. It is possible to mix A and B and supply them to the hollow part by utilizing the solvent-swelled gel or the thixotropic properties of the gel precursor. Alternatively, in the case of a gel precursor, it is possible to supply and gel inside the mold by utilizing the low viscosity. (2) Case 2: A and B are supplied simultaneously or partially on different lines. (3) Case 3: A method of supplying B and then supplying A. (4) Case 4: A method of supplying A and then supplying B. In the above method, preferably case 2, case 3,
This is the method of Case 4. In these methods, in the supply step of A, A is supplied without swelling of the solvent and B is supplied without swelling of the solvent, so that the cooling effect of the molded article is enhanced and the molding cycle time is shortened. It is preferred. In the case of the above method A, the blow pressure for pressing the parison against the molding surface of the mold may be given by supplying the gel or the gel precursor and the solvent into the parison. In the case where the blow molding method is used, good transferability can be obtained by heating the molding surface of the mold to a temperature equal to or higher than the Vicat softening temperature (T) ° C. of the parison thermoplastic polymer material. It may be obtained. As a configuration in which the molding surface of the mold is heated to a temperature equal to or higher than the Vicat softening temperature (T) ° C. of the parison material, for example, a space is provided on the back side of the relatively thin cavity molding surface, and heating is performed in the space. It is possible to adopt a configuration in which a fluid (heating (or overheating) steam, heating oil, or the like) is introduced and heated, and / or heating is performed by radiation heating means provided in the space. Regarding a configuration in which a space is provided on the back side of the cavity molding surface and heating is performed from the back side, for example, Japanese Patent No. 2795144 and Japanese Patent No. 2795216
No. 2,798,061 and the like, and these configurations can be used. As a molding method, an injection molding method can also be used. When the injection molding method is used, a hollow portion is formed in a molded product by gas injection, and a gel or a gel precursor and a solvent can be injected into the hollow portion. Simultaneously with or after the injection of the molten polymer into the cavity, a gel or gel precursor and a solvent may be injected into the molten polymer at a high speed so as to spread over the entire region. In other words, the resistance distribution of the molten polymer caused by the temperature distribution of the molten polymer in the cavity (resistance distribution to injected gel and gel precursor and solvent; high distribution near the molding surface and low distribution at the center) Using ()), a gel or a gel precursor and a solvent may be supplied into the molten polymer to form a solvent-swelled gel.

Here, a gel refers to a substance having a three-dimensional network structure insoluble in a solvent. These three-dimensional networks are polycondensed,
Any of covalent bonds such as radical polymerization, thermal polymerization, photoassembly, radiation polymerization, and plasma polymerization, or any of intermolecular bonds such as hydrogen bond, ionic bond, coordination bond, helix formation, hydrophobic bond, and Faderworth bond good. These gels may be injected into the hollow portion of the polymer and gelled at the stage of solvent swelling.
In the injection step, the gel precursor can be gelled by heat after injection or by a gelling agent contained in the solvent.
After removing from the restraining mold, radiation, electron beam, U
V, It is also possible to gel by microwave irradiation. As the solvent, water, various oil low molecular weight compounds and the like can be used. In addition, a freezing point transfer agent such as PEG and a salt can be added to these solvents. The preferred solvent is water. As a gel or gel precursor,
For example, starch such as starch-acrylonitrile graft polymer hydrolyzate, starch-acrylic acid graft polymer, starch-vinyl sulfonic acid graft polymer, starch-acrylamide graft polymer, esterified starch, etherified starch, etc .; Acrylonitrile graft polymer, cellulose-styrene sulfonic acid graft polymer, acetylcellulose, ethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose, carboxymethylethylcellulose, cross-linked cellulose of carboxymethylcellulose, agarose, agaropectin, amylose , Amylopectin, acacia, arabinan, alginate, alginic acid pro Natural products such as lenglycol, curdlan, casein, carrageenan, xanthan gum, chitin chitosan, guar gum, glucomannan, yeast mannan, gelatin, dextran, hyaluronic acid, locust bingham, and derivatives thereof, or polyvinyl alcohol gels Acrylic gels such as crosslinked sodium polyacrylate, sodium acrylate, saponified vinyl alcohol copolymer (methyl acrylate-vinyl acetate copolymer), saponified polyacrylonitrile polymer, and hydroxyethyl methacrylate polymer; Addition polymer systems such as isobutylene maleate (co) polymer and vinylpyrrolidone (co) polymer; polyethylene glycol / diacrylate crosslinked polymers; condensation of ester polymers and amide polymers System; polyurethane; synthetic organic polymers silicone such as silicone, water glass, inorganic polymers, such as bentonite can also be used. Also, metal soaps such as 12-hydroxystearic acid metal soap and amino acids such as benzyldensorbitol amino acid can be used. These gels or gel precursors can be used alone or in combination of two or more. The mixing ratio between the gel or the gel precursor and the solvent can be appropriately determined in order to obtain the desired properties of the solvent-swollen gel, but preferably from 1: 1000 to 1:
10, more preferably 1: 500 to 1:30, particularly preferably 1: 200 to 1:50.

[0007] Examples of the material for molding the hollow polymer include thermoplastic polymers and elastomers. (1) Examples of the thermoplastic polymer include the following polymers. (a) For example, AS resin, polystyrene, high impact polystyrene, acrylonitrile-butadiene rubber-
Graft copolymer composed of styrene (ABS resin), graft copolymer composed of acrylonitrile-butadiene rubber-styrene-α-methylstyrene (heat-resistant ABS resin), acrylonitrile-ethylene-propylene rubber-styrene and / or methyl methacrylate (AES resin), graft copolymer of acrylonitrile-hydrogenated diene rubber-styrene and / or methyl methacrylate, graft copolymer of acrylonitrile-silicone rubber-styrene and / or methyl methacrylate Coalescence, polyethylene, polypropylene, polycarbonate, polyphenylene ether, polyoxymethylene, nylon, methyl methacrylate polymer, polyether sulfone, polyarylate, vinyl chloride, maleimide compound Styrene and / or acrylonitrile and / or copolymers of α- methyl styrene, rubber-like polymer - maleimide compounds - styrene and /
Or a resin such as a graft copolymer comprising acrylonitrile and / or methyl methacrylate and / or α-methylstyrene. (b) Diene block polymers such as styrene-butadiene-styrene block polymer and styrene-isoprenestyrene block polymer. (c) For example, diene-based hydrogenated polymers such as styrene-butadiene-styrene hydrogenated block polymer and styrene-isoprene-styrene hydrogenated block polymer (trade names: "Dinalon" by JSR Corporation, "Septon" by Kuraray Co., Ltd.) And Shell Co., Ltd. "Clayton G" are known). (d) a blend of the above (b) and a polyolefin,
A blend of (c) and a polyolefin. (e) thermoplastic polyurethane. (2) Examples of the elastomer include the following. (a) For example, natural rubber, polyisoprene rubber, styrene butadiene rubber, polybutadiene rubber, acrylonitrile butadiene rubber, ethylene propylene rubber, acrylic rubber, chloroprene rubber, hydrin rubber, norportene rubber, silicone rubber, polyurethane rubber. The molding material is preferably a thermoplastic polymer. When a thermoplastic polymer is used as a molding material, blow molding is excellent, and the surface appearance of the obtained hollow article is also excellent.

Examples of molded articles include exterior parts for vehicles such as bumpers, fenders and door outer panels, interior parts for vehicles such as instrument panels, glove boxes and door trims, and perfect materials, partition plates and flooring materials. In addition to civil engineering members such as building members, road noise insulation walls, and vibration absorbing structures, various housings, sports products, playground equipment, furniture products, sanitary products, and kitchen products can be exemplified. Further, the surfaces of these molded products may be subjected to plating, sputtering, vapor deposition, painting, or the like. Alternatively, various heat storage materials can be exemplified. Specific examples of vehicle products include floor materials, engine mounters, engine /
There are indoor shield plates, oil pans, air spoilers, hoods, sunroofs, rear gates, wheel caps, console boxes, armrests, headrests, fuel tanks, driver's seat covers, trunk tool boxes, and the like.
Specific examples of products for building components include, in addition to the above wall materials,
Ceiling panels, window frames, doors, benches, flooring, especially gym flooring,
Etc. Specific examples of the housing include a speaker box, a cooler box, a TV, an audio device, a printer, a fax machine, a copier, a game machine, a washing machine, an air conditioner, a refrigerator, a vacuum cleaner, an attache case, an instrument case,
There are tool boxes, containers, camera cases, and outboard motor covers for pleasure boats. Specific examples of sports products include skis, snowboards, skateboards, ice hockey sticks, curling balls, gateball rackets, tennis rackets, canoes, boats, and the like. Specific examples of play equipment include bats, blocks, blocks, fishing tackle cases, pachinko underframes, and the like. Specific examples of furniture products include drawers, desk tops, bed tops and bottoms, mats, mirror base frames, grated boxes and their front doors, chair backs and bottoms,
Trays, trays, umbrella stands, vases, medicine boxes, hangers, makeup boxes, storage boxes, book stands, office desk tops, OA desk tops, OA racks, books, clothing, cupboards, and art case There is a base stand. Specific examples of sanitary products include shower heads, toilet seats, toilet plates, drain pans, water tank lids, vanity doors, bathroom doors, and the like. Specific examples of kitchen products include:
There are cutting boards, kitchen doors, etc. In addition, these are illustrations, and molded articles other than these can also be suitably molded.

[0009]

Embodiments of the present invention will be described below. Note that the present invention is not limited to the following specific configurations, and various modifications can be made within the scope of the present invention. FIG. 1 is an overall configuration of a blow molding apparatus for molding each molded product of Example 1, Example 2, and Comparative Example, and FIG. 2 is a cross section of a mold (only one side is shown because of substantially symmetry) used in the apparatus of FIG. ,
FIG. 3 schematically shows a cross section of a parison supplied between the molds of FIG. 2 by the apparatus of FIG. The blow molding apparatus shown in FIG. 1 uses an extruder 11 to form a molding material (Examples 1 and 2).
And Comparative Example, ABS resin) was melted (about 200 ° C. to 240 ° C. in Examples 1 and 2 and Comparative Example) and sent to the accumulator die 12, and was sent downward by the accumulator die 12 as a parison 20 having a hollow cylindrical shape. The parison 20 is sandwiched between the molds 30 shown in FIG. 2 and is pressed against the molding surface 311 by blow pressure. In the first embodiment, the blowing pressure is given by the gel or the gel precursor and the solvent supplied to the inside of the parison 20. In the example 2 and the comparative example, the pressure is given by the pressure of the air blown into the parison 20. That is, the molded article of Example 1 is formed by supplying gel and water to the inside of the parison 20 after clamping the mold, and using the pressure as a blow pressure. That is, it is formed by the above-mentioned method A. Further, the molded article of Example 2 is formed by clamping the parison 20, forming a hollow molded article by using air pressure as a blow pressure, and supplying gel and water to the hollow portion of the molded article. It was done. That is, it is formed by the above-mentioned method. Example 2
FIG. 5 shows a molding procedure of the molded product of FIG. The molded article of the comparative example is a hollow molded article molded by using the pressure of air as a blow pressure after clamping the parison 20. In Examples 1 and 2, the weight ratio of gel (Sunfresh ST-100MPS (grafted starch type) manufactured by Sanyo Chemical Industries, Ltd.) to water was 1: 100.
It is. The mold 30 has a desired shape and shape as shown in FIG.
The cavity 31 includes a thin (about 10 mm maximum) stainless steel cavity 31 having a molding surface 311 in a surface state (mirror surface / texture surface, etc.) and a stainless steel support 32 for supporting the cavity 31. A space 33 is provided between the back side of the molding surface and the support 32. Further, the cavity 31 and the support 32 are insulated by arranging a heat insulating material in a contact portion between the cavity 31 and the support 32. Also,
The heat insulating material is also provided on the inner surface of the support 32 facing the space 33.

When a heating fluid (heating (or overheating) steam, heating oil, or the like) is fed into the space 33 as shown by an arrow a, the surface temperature of the molding surface 311 is reduced by the parison 20.
Prior to contact with the molding surface 311, the parison 20 is heated to a temperature equal to or higher than the Vicat softening temperature (T) ° C. of the molding material (ABS resin in Examples and Comparative Examples). For this reason, the state of the molding surface 311 is satisfactorily transferred to the outer surface of the parison 20. After the heating, the heating fluid in the space 33 is discharged from the space 33 as shown by the arrow b, and then the cooling fluid (cooling water or cooling oil) is sent in as shown by the arrow a. Molding surface 311 made of
Is rapidly cooled to a temperature equal to or lower than the Vicat softening temperature ((T) -10) ° C. of the molding material of the parison 20. For this reason, the molding cycle is shortened. In addition, in the case of Examples 1 and 2, cooling is also performed by the gel and water supplied into the parison 20. In other words, parison 2
The temperature of 0 is a high temperature (200 ° C. to 240 ° C.), but the temperature of the gel and water is lower than the temperature of the parison 20, so that a cooling effect is exerted. The parison 20 is formed by the cooling described above. When the gel supplied to the inside of the parison 20 after forming the parison 20 or at the time of forming the parison 20 absorbs water and turns into a solvent swelling gel, the molding cycle is completed, the mold 30 is opened, and the molded article 21 is taken out. . As described above, since the inner gel absorbs water and turns into a solvent swelling gel, the gel is taken out of the mold 30. Therefore, even if the surface layer (portion formed by the parison 20) is as thin as 1 mm or less, the molded product Maintains its shape without deformation. That is, a molded article having excellent dimensional stability can be obtained. Since the cavity 31 is repeatedly heated and cooled as described above, a mechanism is provided between the cavity 31 and the support body 32 that supports the cavity in an adiabatic manner to absorb a deviation due to thermal expansion.

[0011]

[Table 1] Table 1 shows the molding conditions and the results of the impact absorption performance test by the falling ball method for each of the molded products of Examples 1 and 2 and Comparative Example molded as described above. The impact-absorbing performance test by the falling ball method means that 80 g of steel balls (diameter 27 mm)
This is a method of dropping from a height of 0 cm and examining the rebound height. In addition, in order to regulate the falling path and the rebound path, the steel ball is made to fall in a transparent cylindrical cylinder and rebound. From Table 1, it can be seen that the molded products of Examples 1 and 2 are superior in the impact absorption performance to the molded products of Comparative Examples.

[0012]

According to the present invention, it is possible to provide a molded article having excellent characteristics in one or more of shape rigidity, shock absorption, vibration absorption, sound insulation, heat insulation, light weight, and the like. it can. In addition, it is possible to provide a molded product having the above characteristics and high dimensional accuracy. In addition, a molded product having the above characteristics can be produced in a relatively short molding cycle.
It can be manufactured with high productivity. In addition, a molded product having the above characteristics can be manufactured with high productivity without using a special device in manufacturing.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a blow molding apparatus for molding an example product and a comparative example product.

FIG. 2 is a schematic view showing a cross section of a mold (one side) used in the blow molding apparatus of FIG.

FIG. 3 is a schematic diagram showing a cross section of a parison supplied between the molds of FIG. 1 (one side is not shown).

FIG. 4 is a schematic view illustrating a method for supplying A and B in the b method.

FIG. 5 is a schematic view showing a manufacturing process of the product 2 of the embodiment.

[Explanation of symbols]

 Reference Signs List 20 parison 30 mold 31 cavity 311 molding surface

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Mihara 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd. (72) Fumio Kurihara 2-11-11 Tsukiji 2-chome, Chuo-ku, Tokyo JSR F term (reference) 4F208 AE02 AE06 AE07 LA01 LB01 LN03 LW01 LW50

Claims (6)

[Claims] 1. A molded article obtained by supplying a gel or a gel precursor and a solvent to a hollow portion of a hollow polymer article restricted by a mold. 2. The molded article according to claim 1, wherein the gel or gel precursor supplied to the hollow portion absorbs at least a part of the solvent to form a solvent-swollen gel, and then releases the constraint of the mold to obtain the molded article. . 3. The molded article according to claim 1, wherein the hollow polymer article restrained by a mold is obtained by blow molding. 4. A material for forming a hollow polymer article is a thermoplastic polymer, and the forming material is pressed in a molten state onto a cavity molding surface heated to a temperature not lower than the Vicat softening temperature (T) ° C. of the thermoplastic polymer. The molded article according to any one of claims 1 to 3, wherein a polymer hollow article is obtained by the method. 5. A molded article formed by bringing a polymer into contact with a cavity molding surface in a molten state and supplying a gel or a gel precursor and a solvent into the inside of the polymer and pressing the cavity molding surface. 6. A polymer is brought into contact with a molding surface of a mold in a molten state, and a gel or a gel precursor and a solvent are supplied to the inside or the internal space of the polymer and pressed against the molding surface of the mold.
A method of molding a molded article, in which the mold or mold is opened and the molded article is taken out after the gel or gel precursor absorbs at least a part of the solvent to form a solvent-swelled gel.