JP4892274B2 - Highly adhesive liquid crystal polymer molded body and method for producing the same - Google Patents

Description

  The present invention relates to a liquid crystal polymer molded article excellent in adhesiveness and a method for producing the same.

  In recent years, liquid crystal polymers have attracted attention as relatively new resin materials. The liquid crystal polymer is not only excellent in chemical resistance and the like, but also has low hygroscopicity and excellent dielectric properties, so that it is expected to be used particularly as an insulator material for electronic circuit boards.

  However, liquid crystal polymers have the disadvantage of low adhesion. For example, when a liquid crystal polymer is used as an electronic circuit board material, a circuit is formed on a liquid crystal polymer film and then the circuit surface is protected with a cover film, or a glass cloth impregnated with an epoxy resin (hereinafter referred to as “ Sometimes referred to as “glass / epoxy material”) and other circuit boards. In some cases, a liquid crystal polymer film is bonded to another circuit board as a reinforcing plate such as a flexible circuit board or a cover film for a circuit surface. However, the liquid crystal polymer has insufficient adhesion to an adhesive such as an epoxy resin used in an electronic circuit board. Therefore, a technique for improving the adhesion of the liquid crystal polymer has been devised.

  For example, chromic acid mixed solution treatment or corona discharge treatment has been conventionally known as a method for improving the surface properties of polymer films to enhance adhesion, but for liquid crystal polymers with high chemical stability, Therefore, a high reforming effect cannot be obtained.

  Therefore, as a method for improving the surface characteristics of the liquid crystal polymer film, Patent Document 1 discloses a method of performing adhesion promotion coating on the film surface, and Patent Documents 2 and 3 disclose a method of irradiating ultraviolet light having a wavelength of 184.9 nm. Patent Document 4 proposes a method of performing a gas discharge plasma treatment in the presence of a gaseous oxygen atom-containing compound.

  However, in the method described in Patent Document 1, coating materials such as acrylic, polyester, polyimide, polyurethane, and polyamide are inferior in terms of heat resistance, water absorption, and the like as compared with a liquid crystal polymer that is a base material. As a result, the properties of the resulting product are reduced due to the coating material, and the properties of the liquid crystal polymer cannot be utilized. Further, since the coating process is complicated, there arises a problem that the processing cost increases.

  In the methods by ultraviolet irradiation described in Patent Documents 2 and 3, although adhesion to a copper foil or the like is improved when the film is melted and bonded, an adhesive for circuit boards such as epoxy resin, glass / Adhesive strength with epoxy material does not improve much.

Patent Document 4 proposes a method of performing a gas discharge plasma treatment in the presence of a gaseous oxygen atom-containing compound so that the molar ratio of oxygen atoms on the surface is 1.2 times that of the inside. This technique improves the affinity with an adhesive or the like by subjecting a liquid crystal polymer to plasma irradiation treatment in the presence of an oxygen atom-containing compound. By this treatment, the molar ratio of oxygen atoms to carbon atoms in the surface portion is said to be 1.2 times or more of the internal molar ratio. From this fact, it is not necessarily clear, but it is considered that the liquid crystal polymer molecules are cleaved by plasma treatment and hydroxyl groups are introduced into the generated radical sites, thereby increasing the reactivity on the surface.
JP-A-10-316777 (Claims) JP-A-1-216824 (Claims) JP-A-1-236246 (Claims) JP 2000-49002 (Claims, Examples, Tables 6 and 7)

  As described above, various techniques for performing a surface modification treatment in order to improve the adhesion of a liquid crystal polymer having relatively poor adhesion have been known. In particular, Patent Document 4 discloses experimental data in which the adhesive strength to an adhesive or a plated copper layer is improved by plasma-treating the surface of a liquid crystal polymer film. However, it has been found that such a plasma processing technique has a problem. That is, according to the result of the Example described in Patent Document 4, the adhesive strength is certainly improved. However, even if the initial adhesive strength is high, the adhesiveness may not continue and the adhesive durability may be poor. Such a durability problem naturally affects the durability of the electronic device, particularly when the liquid crystal polymer is used as an insulator material for the electronic circuit board.

  Therefore, the problem to be solved by the present invention is that not only the initial adhesiveness but also the long-term adhesiveness is improved, and the liquid crystal polymer molded body excellent in long-term reliability, its production method, and the film-like liquid crystal polymer molded body It is providing the liquid crystal polymer laminated body containing this, and a liquid crystal polymer circuit board.

  In order to solve the above-mentioned problems, the inventors of the present invention have intensively studied on the conditions for improving the long-term reliability by irradiating plasma on the adherend portion of the liquid crystal polymer molded body. As a result, if the output is increased too much in the plasma treatment, the initial adhesion will be improved, but it will not continue and the durability will be inferior, so the plasma treatment should be performed with the output adjusted appropriately. I found. Further, the inventors have found that such an improvement in durability can be achieved by defining a specific functional group ratio, and thus completed the present invention.

  The highly adhesive liquid crystal polymer molded product of the present invention has [-CO-bond] and [-COO-bond] occupying the C (Is) peak intensity in the X-ray photoelectron spectroscopic analysis result of the surface portion of the adherend site. ] And the peak intensity ratio [—C—O— bond] / [— COO— bond] is 1.5 or less.

  A film is suitable as the shape of the highly adhesive liquid crystal polymer molded body. The film-like high-adhesive liquid crystal polymer molded product according to the present invention has characteristics that the liquid crystal polymer itself has excellent dielectric properties and low hygroscopicity, and has improved adhesion to other adhesives and other materials. Therefore, it is particularly useful as an insulator for electronic circuit boards, a reinforcing plate for flexible circuit boards, a cover film for circuit surfaces, and the like.

  As the film-like high-adhesive liquid crystal polymer molded body according to the present invention, a metal layer is laminated and the adhesion of a non-laminate surface to be adhered is increased, a circuit is formed, and An example in which the adherence of the adherend other than the circuit is enhanced can be exemplified. These are useful as electronic circuit board materials with high long-term reliability.

The method for producing a highly adhesive liquid crystal polymer molded product according to the present invention is as follows.
A method for producing the highly adhesive liquid crystal polymer molded body,
Characterized in that it includes a step of performing surface treatment by irradiating at least an adherend part of the liquid crystal polymer molded body with plasma under conditions of an output of 0.6 W / cm ² or less and a pressure of 0.1 Torr or more in an oxidizing gas atmosphere. To do.

  In the above manufacturing method, it is preferable to perform plasma irradiation in a reactive ion etching mode. Direct plasma mode is common in plasma treatment, but according to reactive ion etching mode, the polymer molded body can be surface-modified more appropriately, and durability on the adhesion surface can be further improved. .

  The highly adhesive liquid crystal polymer molded product of the present invention is excellent not only in the initial adhesiveness at the adherend site but also in the long-term adhesiveness and high in long-term reliability. Therefore, the highly adhesive liquid crystal polymer molded body of the present invention is extremely useful as an insulator material for an electronic circuit board having excellent durability, for example, by forming a metal layer or a circuit thereon to form a laminate. Moreover, the method of the present invention is extremely useful industrially as being capable of producing the highly adhesive liquid crystal polymer molded body of the present invention.

The highly adhesive liquid crystal polymer molded product of the present invention is
In the result of X-ray photoelectron spectroscopy analysis of the surface portion of the adherend site, the sum of the peak intensities of [—C—O— bond] and [—COO— bond] in the C (Is) peak intensity is 21% or more. The ratio of peak intensity [—C—O— bond] / [— COO— bond] is 1.5 or less.

  The highly adhesive liquid crystal polymer molding of the present invention comprises a liquid crystal polymer. The liquid crystal polymer is particularly useful as an insulator material for an electronic circuit board because it is a thermoplastic resin having excellent heat resistance and also has excellent dielectric properties. The type of the liquid crystal polymer is not particularly limited, and examples thereof include a thermotropic liquid crystal polymer that exhibits liquid crystallinity in a molten state. In the present invention, a thermotropic liquid crystal polymer is preferable, and more specifically, a thermotropic liquid crystal polyester or a thermotropic liquid crystal polyester amide is preferable.

  Thermotropic liquid crystal polyester (hereinafter simply referred to as “liquid crystal polyester”) is, for example, an aromatic polyester synthesized mainly from aromatic dicarboxylic acid and monomers such as aromatic diol and aromatic hydroxycarboxylic acid. Sometimes it exhibits liquid crystallinity. Typical examples thereof include type I [Formula (1)] synthesized from parahydroxybenzoic acid (PHB), terephthalic acid, and 4,4′-biphenol, PHB and 2,6-hydroxynaphthoic acid. Type II [Formula (2)] synthesized from the above, Type III [Formula (3)] synthesized from PHB, terephthalic acid, and ethylene glycol.

  Examples of the liquid crystal polymer according to the present invention include units represented by the above formulas (1) to (3), as long as they exhibit liquid crystallinity (particularly thermotropic liquid crystallinity) and can achieve the object of the present invention. It may be a copolymer type polymer (for example, 50 mol% or more in all constituent units of the liquid crystal polymer) and also having other units. Examples of the other unit include a unit having an ether bond, a unit having an imide bond, and a unit having an amide bond.

  Moreover, as liquid crystal polyester amide, the said liquid crystal polyester which has an amide bond as another unit corresponds, for example, what has a structure of the following Formula (4) is mentioned. For example, in the formula (4), the molar ratio of the unit of s, the unit of t, and the unit of u is 70/15/15.

  The liquid crystal polymer used in the present invention may contain a polymer other than the liquid crystal polymer as long as characteristics such as dielectric properties are not excessively given up. The polymer may be simply mixed with a liquid crystal polymer or may be chemically bonded. Examples of such an alloy polymer include, but are not limited to, polyetheretherketone, polyethersulfone, polyimide, polyetherimide, polyamide, polyamideimide, polyarylate, and the like. The mixing ratio of the liquid crystal polymer and the alloy polymer is not particularly limited. For example, the mass ratio is preferably 50:50 to 95: 5, and more preferably 70:30 to 90:10. A polymer alloy containing a liquid crystal polymer can also have excellent properties due to the liquid crystal polymer.

  The liquid crystal polymer of the present invention preferably has a melting point of about 280 to 360 ° C. If it is about 280 ° C. or higher, it can sufficiently withstand the heat of solder reflow, and if it is 360 ° C. or lower, extrusion molding is also possible.

  When the molded body of the present invention is a film or sheet, the molecular orientation is preferably biaxial orientation, and the MD / TD strength ratio is preferably between 1/3 and 3/1, Those between 2/1 are more preferred. When the intensity ratio is in the range, the anisotropy of the linear expansion coefficient (CTE) is also appropriate, and the workability and reliability can be sufficiently secured. Moreover, the thickness is 10-750 micrometers, Preferably it is 25-500 micrometers.

  The shape of the liquid crystal polymer molded body of the present invention is not particularly limited, and can be, for example, a film, a sheet, a fiber, a nonwoven fabric, or the like. Among these, a film is preferable. This is because a metal layer or a circuit is formed on the surface and can be used as a liquid crystal polymer laminate or a liquid crystal polymer circuit board, respectively.

  The liquid crystal polymer molded product of the present invention has [-C—O— bond] and [—COO— bond] in the C (Is) peak intensity in the result of X-ray photoelectron spectroscopy analysis of the surface portion of the adherend site. The sum of peak intensities is 21% or more, and the ratio of peak intensities [—C—O—bond] / [— COO—bond] is 1.5 or less.

In X-ray photoelectron spectroscopy, the inner surface electrons of an atom are excited by irradiating the sample surface with X-rays, and the kinetic energy of the photoelectrons emitted thereby is detected. The chemical bond state is analyzed. C (Is) in this X-ray photoelectron spectroscopic analysis is a peak obtained by photoelectrons derived from carbon atoms present on the sample surface. This peak further includes various peaks depending on the bonding state of the carbon atom, and the position of each peak is determined by the bonding state. For example, the peak position of each bonding state includes [—CH— bond]: 285 eV, [—C—O— bond]: 286.6 eV, [—C—N— bond]: 285.7 eV, [—C = O-bond]: 287.7 eV, [—COO-bond]: 289.4 eV, [—OCOO-bond]: 290 eV, [π-π ^* satellite peak]: 291.9 eV, and waveform separation attached to the apparatus The mechanism can separate each peak.

  In the present invention, in the liquid crystal polymer molded body, X-ray photoelectron spectroscopic analysis is performed on the surface to be an adhesion site in the future to obtain C (Is) peak data, which occupies the C (Is) peak intensity [-C-O- The ratio of the peak intensity of [bond] and [—COO-bond] is obtained.

  The peak intensity of these [—C—O— bonds] and [—COO— bonds] has been found by the present inventors as being deeply related to adhesiveness. That is, when the surface of the liquid crystal polymer is irradiated with plasma in an oxidizing gas atmosphere, the ester bond is generally cleaved and a hydroxyl group is introduced into the generated radical site. Since this hydroxyl group is rich in reactivity and contributes to adhesiveness, the adhesiveness is improved if the ratio of [—C—O— bond] on the surface is high. However, according to the knowledge found by the present inventors, when plasma irradiation is performed under excessively strong conditions or low pressure, the initial adhesiveness can be improved, but the long-term adhesiveness is lowered, and the long-term reliability of the product is impaired. It will be. The cause is not necessarily clear, but it is considered that the plasma irradiation under excessively strong conditions or low pressure causes a carboxyl group generated by cleavage of the ester group to be eliminated as carbon dioxide. Therefore, the present inventors should promote the generation of carboxyl groups rather than hydroxyl groups and increase the number of reactive groups while maintaining the ratio, particularly for maintaining adhesion over a long period of time, that is, for long-term reliability. I found. Considering this point further, as a particularly important index in the present invention, the sum of the peak intensity of [—C—O— bond] and [—COO— bond] in the C (Is) peak intensity is 21% or more. And that the ratio of peak intensity [—C—O— bond] / [— COO— bond] is 1.5 or less.

  More specifically, depending on the X-ray photoelectron spectrometer, the area of each peak can be obtained simultaneously with the measurement. In the present invention, the area may be adopted as the peak intensity of C (Is), [—C—O— bond], and [—COO— bond].

  Among the provisions of the present invention, if the sum of the peak intensities of [—C—O— bond] and [—COO— bond] occupying the C (Is) peak intensity is 21% or more, the liquid crystal polymer molded article is covered. The cutting of the liquid crystal polymer molecules appropriately proceeds on the surface of the adhesion site, and the reactivity of the surface is increased. As a result, the initial adhesion can be mainly improved. Further, if the ratio of peak intensity: [—C—O—bond] / [— COO—bond] is 1.5 or less, the adhesiveness can be maintained over a long period of time, and the long-term reliability of the product can be improved. .

  In the present invention, maintenance of adhesion over a long period of time, that is, long-term reliability is, for example, when the molded body of the present invention is used as a material for a circuit board for electronic equipment, etc. It means a long life. For example, long-term reliability related to adhesion can be confirmed by adhesion strength retention after PCT (pressure cooker test), which is a long-term reliability test. The PCT here is an accelerated test for confirming the deterioration of the adhesive strength after leaving the sample under the conditions of 121 ° C., 100% RH, and 2 atm, for example. For example, after PCT, the long-term reliability under normal conditions that are actually used can be compared by comparing the time when the adhesive strength retention rate from the initial stage becomes 50%.

  Under normal conditions in which the product is actually used, it is preferable that the product has a lifetime of 2 years or longer. Here, it is said that when the operating temperature rises by 10 ° C., the lifetime is halved. Therefore, after the PCT under the above conditions, if the time for which the adhesive strength retention rate is 50% is 18 hours or more, it can be said that the product life at room temperature is equivalent to 2 years or more, and the long-term reliability is high. .

The conditions of X-ray photoelectron spectroscopy can be employed general ones, is not particularly limited, can be used AlK _alpha as for example X-ray irradiation. Regarding the peak separation method, the distribution function for determining the peak shape is preferably a mixture of a Gaussian function and a Lorentz function, and the half-value width of each peak is preferably made as constant as possible.

  In the liquid crystal polymer molded body of the present invention, the above-mentioned provision concerning X-ray photoelectron spectroscopic analysis needs to be satisfied at least at the adherend site, but naturally the above-mentioned provision is also fulfilled at portions other than the adherend portion. May be.

  Since the highly adhesive liquid crystal polymer molded article of the present invention has enhanced adhesion of the surface portion at the adherend site, other substances or the liquid crystal polymer molded article of the present invention can be adhered to the adherend site. . For example, other sheets, films, and circuit boards can be laminated on the film-like highly adhesive liquid crystal polymer molded body through an adhesive or simply by thermocompression bonding.

  As the highly adhesive liquid crystal polymer molded article of the present invention, at least the adherend part of the molded article composed solely of the liquid crystal polymer is plasma-treated, and may exhibit a predetermined X-ray photoelectron spectroscopic analysis result. A metal layer or a circuit may be laminated or formed.

  For example, a highly adhesive liquid crystal polymer laminate in which a metal layer such as copper foil is laminated on one side of the liquid crystal polymer film and the other side is plasma-treated; a circuit is formed on one side of the liquid crystal polymer film, High adhesion liquid crystal polymer circuit board whose other surface is plasma-treated; high adhesion liquid crystal polymer in which a circuit is formed on at least one surface of a liquid crystal polymer film and at least a portion other than the circuit on the circuit surface is plasma-treated Circuit board and the like.

  Since the above laminate and circuit board have improved adhesion to epoxy resin, etc., when laminating similar circuit board materials and other circuit board materials, or when covering the circuit surface with a cover film Even if it exists, not only initial adhesiveness but long-term adhesiveness is shown with respect to these, and the long-term reliability of a product can be improved.

  Moreover, it is good also as a liquid crystal polymer laminated body by laminating | stacking a metal layer on the to-be-adhered site | part of the highly adhesive liquid crystal polymer molded object which concerns on this invention whose shape is a film. Furthermore, a circuit can be formed by etching the metal layer, or a circuit can be formed by directly adhering the circuit to a part to be bonded, thereby forming a liquid crystal polymer circuit board. These laminates and circuit boards are highly reliable because the adhesion between the liquid crystal polymer film and the metal layer or circuit is improved. As described above, these laminated body and circuit may be further subjected to plasma treatment on the non-laminated surface or the circuit surface.

The high-adhesive liquid crystal polymer film of the present invention irradiates plasma to at least the adherend of the liquid crystal polymer film under an oxidizing gas atmosphere under conditions of output: 0.6 W / cm ² or less and pressure: 0.1 Torr or more. Can be manufactured.

  As the oxidizing gas, oxygen, air containing oxygen, carbon monoxide, carbon dioxide, or the like can be used.

  Plasma irradiation is performed by supplying power by a capacitive coupling method in a frequency band from direct current to high frequency (RF) between a pair of discharge parallel plate electrodes in an atmosphere in which the oxidizing gas is introduced after decompression. This is carried out by generating a discharge and irradiating the surface of the liquid crystal polymer molded body.

Output of plasma irradiation treatment is preferably 0.6 W / cm ² or less, 0.3 W / cm ² or less being more preferred. If it is 0.6 W / cm ² or less, it is possible to improve long-term adhesion because it does not involve excessive cutting of liquid crystal polymer molecules while improving the reactivity of the surface of the molded article, that is, adhesion. . Specifically, in the X-ray photoelectron spectroscopic analysis, the peak intensity ratio [—C—O— bond] / [−] is increased while increasing the peak intensity between [—C—O— bond] and [—COO— bond]. COO-bond] can be moderately suppressed. On the other hand, if the output is 0.05 W / cm ² or more, the reactivity of the surface of the molded body can be sufficiently increased. Therefore, the plasma irradiation is preferably performed at 0.05 W / cm ² or more.

  The pressure in the apparatus is preferably in the range of 0.1 Torr or more (about 13.3 Pa or more). This is because if the pressure in the apparatus is 0.1 Torr or more, the elimination reaction of the carboxyl group caused by the cleavage of the ester group by plasma irradiation can be moderately suppressed, and as a result, long-term adhesion can be maintained. On the other hand, if the pressure is too high, the surface modification effect by plasma irradiation cannot be sufficiently obtained, and sufficient initial adhesive strength may not be obtained. Therefore, the pressure is preferably 5 Torr or less (about 667 Pa or less).

  The plasma irradiation processing mode includes direct plasma (DP) and reactive ion etching (RIE). Direct plasma is a system in which a sample is placed on the ground side, and this has the advantage that radicals can act on the entire sample evenly, so this is used in general plasma processing. Reactive ion etching is a method in which a sample is placed on the RF electrode side as opposed to direct plasma, and ions act on the sample while being accelerated. In the present invention, the reactive ion etching mode is more preferably used from the experimental viewpoint that not only the initial adhesiveness but also the long-term adhesiveness can be further improved.

  Other conditions in the plasma irradiation may be adjusted as appropriate. For example, the processing time is preferably about 10 to 600 seconds. If it is 10 seconds or more, the surface modification effect of the liquid crystal polymer molded product can be sufficiently obtained. On the other hand, the surface modification effect by plasma irradiation mainly depends on the output and pressure and does not increase with time, so it is preferably 600 seconds or less.

  In addition, the present invention is not limited to batch-type parallel plate electrodes, and it is also possible to use a plasma continuous processing apparatus in which film winding and winding are installed inside or outside the vacuum chamber. The type of is not particularly limited.

  Further, in the present invention, in consideration of the future lamination of a cover film, a glass / epoxy material, or a metal layer or a circuit, the plasma is also applied to a portion other than the adherend site to which another substance should be bonded immediately. An irradiation process may be performed.

  In the present invention, the surface of the molded body to be subjected to plasma irradiation means a depth of about 50 to 100 mm from the surface of the film.

  A metal layer, a circuit, or the like can be formed on the adherend portion of the highly adhesive liquid crystal polymer film according to the present invention or a simple liquid crystal polymer film. In the present invention, when a metal layer, a circuit, or the like is formed on a simple liquid crystal polymer film, plasma irradiation treatment is further performed.

  Formation of a metal layer and a circuit can be manufactured by the following method.

(1) Thermal fusion method This method is a method of obtaining a laminate by thermally fusing a metal foil and a film. Examples of the metal foil include various metals such as copper foil, aluminum foil, and gold foil. The thickness is usually 0.01 to 200 μm, preferably 0.1 to 50 μm.

  The heat fusion can be performed by a general method such as a hot press, a heated roll press, or a double belt press. The processing conditions for heat-sealing may be appropriately selected from conditions such as the type and thickness of the metal thin film, the melting point and thickness of the liquid crystal polymer film, etc., but generally the temperature is 180 to 400 ° C. and the pressure is 0.3. It is in the range of -10 MPa.

(2) Sputtering method or vapor deposition method This method is a well-known method in the field of electronic circuit board and optical material production, and is a method of obtaining a laminated body by sputtering or vapor-depositing a metal on a film. Examples of the metal for sputtering or vapor deposition include copper, aluminum, gold, tin, and chromium.

(3) Electroless plating method This method is a well-known method in the field of production of plated products using non-conductive materials such as plastics and ceramics, by depositing metal on a film from a solution containing metal ions. This is a method for obtaining a laminate. Examples of the metal include copper, nickel, cobalt, gold, tin, and chromium.

(4) Method using an adhesive This method is a method of obtaining a laminate by adhering a film and a metal film using an adhesive. Various adhesives such as epoxy, acrylic, and cyanate can be used as the adhesive. In the film / metal layer laminate, the thickness of the film is 10 to 500 μm, preferably 25 to 200 μm. The thickness of the metal layer is 0.01 to 200 μm, preferably 0.1 to 50 μm.

  When a film-like liquid crystal polymer molded body is used as a circuit board, a circuit can be obtained by etching the metal layer of the liquid crystal polymer laminate. In this case, copper, aluminum, gold, tin, chromium or the like is preferably used as the metal to be laminated. The thickness of the film is 10 to 200 μm, preferably 25 to 125 μm, and the thickness of the metal layer is 3 to 100 μm, preferably 5 to 50 μm.

  The highly adhesive liquid crystal polymer according to the present invention has not only initial adhesiveness to glass layers and other circuit boards impregnated with metal layers, adhesives, epoxy resins, etc., but also long-term adhesiveness, that is, long-term reliability. Are better. Therefore, as a result, the present invention has a very high utility value as a product that can significantly extend the product life of electronic devices and the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. It is also possible to implement, and they are all included in the technical scope of the present invention.

Examples 1 and 2 and Comparative Examples 1 to 3
A liquid crystal polymer film (Japan Gore-Tex, product name “STABIAX ST175”, 100 mm × 100 mm × thickness 175 μm) is used as a parallel plate electrode type plasma device 1 (electrode shape: round shape with a diameter of 120 mm, distance between electrodes: 50 mm) The chamber volume was fixed between 10.6 L), and the pressure was reduced to 0.06 Torr (about 8.0 Pa) or less with a vacuum pump. The gas shown in Table 1 was introduced into the apparatus, the gas flow rate was adjusted, and the pressure shown in Table 1 was set. Next, a high frequency voltage of 13.56 MHz was applied between the electrodes, plasma was generated in the processing mode RIE, and the plasma treatment of the film surface was performed. The plasma treatment conditions were a pressure of 0.15 Torr (about 20.0 Pa), and the output and treatment time are shown in Table 1. In addition, an untreated liquid crystal polymer film is set as Comparative Example 1, and the underline in the table indicates that it is outside the specified range of the present invention.

Examples 3-5 and Comparative Examples 4-6
A liquid crystal polymer film (Japan Gore-Tex, product name “STABIAX ST175”, 250 mm × 250 mm × thickness 175 μm) is a parallel plate electrode type plasma device (Samco, plasma dry cleaner Model PX-1000, electrode shape: It was fixed between parallel electrodes having a rectangular shape with a width of 350 mm × a length of 428 mm, a distance between electrodes: 40 mm, and a chamber volume: 129 L), and the pressure was reduced to 0.02 Torr (about 2.7 Pa) or less with a vacuum pump. The gas shown in Table 1 was introduced into the apparatus, the gas flow rate was adjusted, and the pressure shown in Table 1 was set. Next, a high frequency voltage of 13.56 MHz was applied between the electrodes, plasma was generated in the processing modes shown in Table 1, and plasma treatment of the film surface was performed. The plasma treatment conditions were an output of 0.3 W / cm ² and a treatment time of 60 seconds.

Test Example 1 X-ray photoelectron spectroscopic analysis For the plasma-treated surface of each liquid crystal polymer film prepared in the above examples and comparative examples, the sum of peak intensities of [—C—O— bonds] and [—COO— bonds]; The ratio of peak intensity: [—C—O— bond] / [— COO— bond] was determined using an X-ray photoelectron spectrometer (JPS-90MXS MICRO, manufactured by JEOL Ltd.). That is, the ratio of the peak area of [—C—O— bond] and [—COO— bond] to the total peak area of each peak of C (Is) observed according to each functional group is calculated, and the above sum is calculated. And the ratio was calculated. Further, with MGK _alpha as X-ray irradiation. The results are shown in Table 2.

Test Example 2 Measurement of Adhesive Strength An epoxy adhesive (NIKAFLEX SAF, manufactured by Nikkan Kogyo Co., Ltd.) was applied to the plasma treated surface of each liquid crystal polymer film prepared in the above Examples and Comparative Examples, and then electrolytic copper A foil (manufactured by Furukawa Circuit Foil Co., Ltd., GTS-STD-35, thickness 35 μm) was stacked, and then hot pressed at 160 ° C. and 4 MPa for 40 minutes, and this was used as a sample for evaluation. Next, PCT (pressure cooker test) was performed as a long-term reliability evaluation of adhesiveness. Specifically, the evaluation sample is held at 121 ° C. and 100% RH for 12 hours or 24 hours, and the evaluation sample is punched into a width of 5 mm × a length of 100 mm before and after the treatment, and the copper foil / adhesive Peel strength at the interface with each liquid crystal polymer film, and set the copper foil / adhesive and film on the chuck of a tensile tester (Toyo Seiki, Strograph E5D), and then peel off at a speed of 50 mm / min. Asked. Moreover, the time for the adhesive strength to be halved was calculated from the relationship between the PCT treatment time (0, 12 and 24 hours) and the adhesive strength. Table 2 shows the adhesive strength before PCT, the adhesive strength after 24 hours of PCT, and the time during which the adhesive strength is halved.

  As shown in Table 2, when the surface of the liquid crystal polymer film was measured by X-ray photoelectron spectroscopy, the peaks of [—C—O— bond] and [—COO— bond] in the C (Is) peak intensity were measured. When the sum of the strengths is less than 21% (Comparative Example 1), or when the ratio of peak intensities: [—C—O—bond] / [— COO—bond] exceeds 1.5 (Comparative Examples 2 to 6) ) Shows that even when the initial adhesive strength is relatively high, the adhesive strength is greatly reduced after being held under severe conditions, and the reliability under long-term use is lacking. More specifically, since the time during which the adhesive strength retention rate is 50% after PCT is less than 18 hours, the lifetime is considered to be less than 2 years under normal conditions of actual use.

  On the other hand, when the sum of the peak intensities is 21% or more and the ratio of the peak intensities is 1.5 or less, and plasma treatment is performed in an oxidizing atmosphere, the adhesive strength is reduced even after being held under severe conditions. Less, the half-time of the adhesive strength exceeds 18 hours, and it was demonstrated that the reliability under long-term use is high.

  In addition, when the plasma treatment is performed in the processing mode: RIE, the roughness of the surface portion of the liquid crystal polymer film is relatively large, the initial adhesive strength is excellent, and the decrease in the adhesive strength is further reduced even after being held under severe conditions. I understood that.

Claims (6)

A liquid crystal polymer molded article having excellent adhesiveness,
In the result of X-ray photoelectron spectroscopy analysis of the surface portion of the adherend site, the sum of the peak intensities of [—C—O— bond] and [—COO— bond] in the C (Is) peak intensity is 21% or more. And a ratio of peak intensity [—C—O— bonds] / [— COO— bonds] is 1.5 or less, a highly adhesive liquid crystal polymer molded article.   The highly adhesive liquid crystal polymer molded product according to claim 1, wherein the shape is a film.   The highly adhesive liquid crystal polymer molded article according to claim 2, wherein the metal layer is laminated.   The highly adhesive liquid crystal polymer molded article according to claim 2, wherein a circuit is formed. A method for producing a highly adhesive liquid crystal polymer molded product according to any one of claims 1 to 4,
A highly adhesive liquid crystal comprising a step of subjecting a liquid crystal polymer molded body to a surface treatment by irradiating with plasma to at least an adherend part under conditions of an output of 0.6 W / cm ² or less and a pressure of 0.1 Torr or more in an oxidizing gas atmosphere. A method for producing a polymer molded body.   The method for producing a highly adhesive liquid crystal polymer molded product according to claim 5, wherein plasma irradiation is performed in a reactive ion etching mode.