Resin composition and film

Abstract

The invention provides a resin composition (X), and a molded body and a film comprising the same. The resin composition (X) contains 50-95 parts by mass of a polybutylene terephthalate (A) and 5-50 parts by mass of a 4-methyl-1-pentene-alpha-olefin copolymer (B) that satisfies the following requirements (B-a) (where the total of the polybutylene terephthalate (A) and the 4-methyl-1-pentene-alpha-olefin copolymer (B) is 100 parts by mass). Condition (B-a): 60-90 mol% of a structural unit (i) derived from 4-methyl-1-pentene, and 10-40 mol% of a structural unit (ii) derived from a C2-4 alpha-olefin (wherein the total of the structural unit (i) and the structural unit (ii) is 100 mol%). ).

Description

Technical Field

[0001] This invention relates to resin compositions and films. Background Technology

[0002] Flexible printed circuits (FPCs) are highly reliable flexible printed circuit boards made with polyimide and polyester film as substrates. They are characterized by high wiring density, light weight and thinness, and the ability to be bent.

[0003] A typical FPC is a structure in which an adhesive layer is formed on a base film (such as a polyimide film) that serves as a thin-film insulator, and then a conductor foil is bonded thereon.

[0004] In the printed circuit board manufacturing process, thermosetting adhesives are typically used to bond a substrate on which circuitry is formed and a cover layer that protects the substrate. When the circuitry is only located on one side of the substrate, the cover layer is bonded to only one side of the substrate. When the circuitry is interleaved on two or more sides of the substrate, the cover layer is bonded to both sides of the substrate.

[0005] When bonding the cover layer, the substrate and the cover layer coated with a thermosetting adhesive are held in place by a metal plate, and the metal plate is heated and pressurized. At this time, a release film is used to prevent the metal plate from sticking to the cover layer.

[0006] Especially when release films are used in FPC manufacturing processes, one of the required characteristics is that the release film can be easily peeled off from the heat-cured printed circuit board (i.e., release property).

[0007] As a membrane material with release properties, fluorinated polymers such as polyvinyl fluoride, polytetrafluoroethylene, and tetrafluoroethylene-hexafluoropropylene copolymer, as well as polymers such as polymethylpentene and polybutylene terephthalate have been used.

[0008] Furthermore, in printed circuit boards, terminal portions formed for electrical connection with other components are exposed and not covered by a capping layer. Moreover, the adhesive applied to the capping layer used to cover portions other than the terminal portions sometimes melts during bonding by heating and pressurization. Therefore, the molten adhesive flows into the terminal portions of the circuit, forming an adhesive capping layer, which can sometimes cause poor electrical connections.

[0009] Adhesive flow into the terminal portion can be prevented by using the release film to fill the gaps exposed by the uncovered layer. In this case, the release film must follow the elevation difference (i.e., the unevenness) between the covered area and the exposed area such as the terminal portion (followability). If the followability of the release film is insufficient, adhesive may flow into the terminal portion.

[0010] Therefore, from the viewpoint of preventing adhesive from flowing into the terminal portion, the release film used in the FPC manufacturing process requires conformability to the height difference (e.g., uneven shape) between the circuit substrate and the cover layer on the laminate.

[0011] Furthermore, in the FPC manufacturing process, during the heating and pressing molding process to bond the cover layer, the release film is subjected to significant temperature changes in a short period of time, which can easily cause wrinkles to form on its surface. If wrinkles exist in the release film, these wrinkles will be directly transferred to the FPC, resulting in insufficient conformity to height differences and potentially hindering the manufacture of high-quality FPCs.

[0012] As a release film that improves the balance between stable release properties and followability, for example, Patent Document 1 discloses a release film having a release layer comprising polyester resin on at least one side, wherein the crystallinity of the release layer is 10% or more and 50% or less, and the loss tangent (tanδ) of the release layer at 150°C (measured according to JISK7244, stretching mode, heating rate 5°C / min, frequency 1Hz) is 0.02 or more and less than 0.12.

[0013] In addition, as a release film that can suppress the generation of wrinkles while maintaining release properties, for example, a release film disclosed in Patent Document 2 is a release film suitable for the manufacture of flexible circuit boards. It is characterized in that the surface and the back surface are roughened, the ten-point average roughness Rz of the surface is 4 μm or more and 20 μm or less, and the thickness of the release layer constituting the back surface is 35 μm or more (excluding the case where the ten-point average roughness Rz of the surface is 4 μm or more and 5 μm or less, and the thickness of the release layer constituting the back surface is 35 μm or more and 36 μm or less).

[0014] Existing technical documents

[0015] Patent documents

[0016] Patent Document 1: Japanese Patent Application Publication No. 2016-002730

[0017] Patent Document 2: Japanese Patent Application Publication No. 2019-217780 Summary of the Invention

[0018] The problem that the invention aims to solve

[0019] In recent years, the miniaturization and thinning of circuit boards have been progressing, leading to higher requirements for the properties of release films. In addition, with the increasing speed of FPC manufacturing processes, excessive stress is sometimes applied when peeling off the release film during compression molding.

[0020] In Patent Document 1, the balance between release properties and conformability is improved by combining the crystallinity of the release layer with the loss tangent (tanδ) of the release layer at 150°C. However, research on the release film in Patent Document 1 reveals that because the resin materials used in the release layer and the buffer layer are different, the thermal shrinkage rates of each layer tend to differ significantly under the heating temperature conditions of the FPC manufacturing process, resulting in insufficient dimensional stability of the release film. Therefore, there are concerns that wrinkles may form on the surface of the release film disclosed in Patent Document 1 after heating and pressing, particularly hindering the conformability to minute height differences. Consequently, if wrinkles on the surface of the release film are directly transferred to the FPC, a high-quality FPC may not be obtained.

[0021] In the release film disclosed in Patent Document 2, although release properties can be achieved by roughening both the surface and the back side, the resin materials used for the release layer and the intermediate layer are different. Therefore, under the heating temperature conditions of the FPC manufacturing process, the thermal shrinkage rate of each layer can easily vary greatly, and wrinkles may occur on the surface of the resulting release film. Furthermore, in recent years, due to the continuous miniaturization of circuit patterns on printed wiring substrates, if a release film with roughened surface and back sides, as in Patent Document 2, is used, the ability to follow fine circuit patterns may be insufficient.

[0022] In addition, when polybutylene terephthalate is used as the main component of the film, the surface smoothness of the film tends to be slightly worse because polybutylene terephthalate crystallizes quickly.

[0023] On the other hand, when polymer alloying is carried out by combining polybutylene terephthalate with other resins, the shrinkage in the width direction of the resin film is large during T-die extrusion molding, which can sometimes easily cause a narrowing phenomenon in the width of the resin film.

[0024] In order to solve the above-mentioned problems, the inventors have repeatedly conducted in-depth research and found that the film obtained from the resin composition (X) containing 50 to 95 parts by weight of polybutylene terephthalate (A) and 5 to 50 parts by weight of 4-methyl-1-pentene-α-olefin copolymer (B) that meets specific requirements (wherein, the total of polybutylene terephthalate (A) and 4-methyl-1-pentene-α-olefin copolymer (B) is 100 parts by weight) has excellent conformability to the fine height differences (e.g., uneven shape) of FPC, prevents adhesive from flowing out to the terminal portion, and has excellent suppression of wrinkle formation and release properties, thus completing the present invention.

[0025] One embodiment of the present invention aims to provide a resin composition that exhibits excellent conformability and wrinkle suppression in the resulting molded article. Another embodiment of the present invention aims to provide a film that exhibits excellent conformability and wrinkle suppression.

[0026] Methods for solving problems

[0027] The methods for solving the above problems include the following approaches.

[0028] <1> A resin composition (X) comprising:

[0029] 50-95 parts by weight of polybutylene terephthalate (A), and

[0030] 5-50 parts by weight of 4-methyl-1-pentene-α-olefin copolymer (B) that meets the following requirement (Ba),

[0031] (The total amount of the above-mentioned polybutylene terephthalate (A) and the above-mentioned 4-methyl-1-pentene-α-olefin copolymer (B) is 100 parts by mass);

[0032] Requirement (Ba): Composed of 60-90 mol% of structural units (i) derived from 4-methyl-1-pentene and 10-40 mol% of structural units (ii) derived from α-olefins with 2-4 carbon atoms (wherein the total of structural units (i) and structural units (ii) is 100 mol%).

[0033] <2> according to <1> The resin composition (X) wherein, relative to 100 parts by weight of the resin composition, the content of at least one elastomer selected from the group consisting of polyester elastomer (D) and styrene elastomer (E) is 0 to 30 parts by weight.

[0034] <3> according to <1> or <2> The resin composition (X) wherein the 4-methyl-1-pentene-α-olefin copolymer (B) further satisfies the following requirement (Bb);

[0035] Requirement (Bb): The melting point (Tm) measured by differential scanning calorimetry (DSC) is not observed, or the melting point (Tm) measured by differential scanning calorimetry (DSC) is in the range of less than 160°C.

[0036] <4> according to <1> ~ <3> The resin composition (X) according to any one of the following statements, wherein the 4-methyl-1-pentene-α-olefin copolymer (B) further satisfies the following requirement (Be);

[0037] Requirements (Be): The intrinsic viscosity [η] measured at 135°C in decahydronaphthalene solvent is in the range of 0.8 to 3.0 dl / g.

[0038] <5> according to <1> ~ <4> The resin composition (X) according to any one of the following statements, wherein the 4-methyl-1-pentene-α-olefin copolymer (B) further satisfies the following requirements (Bg);

[0039] Requirements (Bg): The ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), as determined by gel permeation chromatography (GPC), i.e., the molecular weight distribution (Mw / Mn), is in the range of 1.5 to 3.0.

[0040] <6> according to <1> ~ <5> The resin composition (X) according to any one of the following methods, wherein the polybutylene terephthalate (A) has a melt volumetric flow rate (MVR) of 0.5 to 60 cm⁻¹, determined according to JIS K7210-1 (2014) at a temperature of 250°C and a load of 2.16 kgf. 3 / 10-minute range.

[0041] <7> according to <1> ~ <6> The resin composition (X) according to any one of the following methods, wherein the polybutylene terephthalate (A) has a melt volumetric flow rate (MVR) of 15 to 50 cm⁻¹, determined according to JIS K7210-1 (2014) at a temperature of 250°C and a load of 2.16 kgf. 3 / 10-minute range.

[0042] <8> according to <1> ~ <7> The resin composition (X) according to any one of the following methods, wherein the polybutylene terephthalate (A) has a melt volumetric flow rate (MVR) of 25-40 cm⁻¹, determined according to JIS K7210-1 (2014) at a temperature of 250°C and a load of 2.16 kgf. 3 / 10-minute range.

[0043] <9> according to <1> ~ <8> The resin composition (X) according to any one of the following, wherein, relative to 100 parts by weight of the resin composition, the content of at least one elastomer selected from the group consisting of polyester elastomer (D) and styrene elastomer (E) is 5 to 15 parts by weight.

[0044] <10> A molded body comprising <1> ~ <9> The resin composition (X) described in any one of the following statements.

[0045] <11> A membrane comprising <1> ~ <9> The resin composition (X) described in any one of the following statements.

[0046] <12> according to <11> The membrane in question is a single-layer membrane.

[0047] <13> according to <11> or <12> The membrane, wherein the critical surface tension at 23°C is 20~30 mN / m.

[0048] <14> according to <11> ~ <13> The membrane according to any one of the following methods, wherein the storage modulus E' of the solid viscoelasticity at 180°C, measured under the conditions of stretching mode, frequency 1.0 Hz, heating rate 3°C / min, and strain 0.1%, is in the range of 10 to 90 MPa.

[0049] <15> according to <11> ~ <14> The membrane described in any one of the following examples, wherein the maximum value (tanδ peak value) of the loss tangent of the solid viscoelasticity at 20-35°C, measured under stretching mode, frequency 1.0 Hz, heating rate 3°C / min, and strain 0.1%, is in the range of 0.02-0.30.

[0050] <16> according to <11> ~ <15> The film described in any one of the above is a release film.

[0051] <17> according to <11> ~ <16> The film described in any one of the above is a release film used in the manufacturing process of printed wiring substrates.

[0052] Invention Effects

[0053] According to one embodiment of the present invention, a resin composition is provided that exhibits excellent conformability and wrinkle suppression in the resulting molded article. Additionally, according to another embodiment of the present invention, a film exhibiting excellent conformability and wrinkle suppression is provided. Detailed Implementation

[0054] Hereinafter, specific embodiments of the present invention will be described in detail. The description of the constituent elements described below is sometimes based on representative embodiments of the present invention, but the present invention is not limited to any of the following embodiments and can be implemented by appropriate modifications within the scope of the present invention.

[0055] In this specification, the range of values ​​indicated by "~" refers to the range of values ​​before and after "~" as the lower and upper limits. It should be noted that in this specification, when referring to the amounts of each component in the composition, if multiple substances corresponding to each component are present in the composition, unless otherwise specified, this means the total amount of the multiple substances present in the composition.

[0056] In this specification, unless otherwise specified, the units listed before or after the "~" symbol, which indicates a range of values, represent the same unit.

[0057] In this specification, a combination of two or more preferred methods is a more preferred method.

[0058] [Resin Composition (X)]

[0059] The resin composition (X) of the present invention comprises 50 to 95 parts by weight of polybutylene terephthalate (A) and 5 to 50 parts by weight of 4-methyl-1-pentene-α-olefin copolymer (B) satisfying the following condition (Ba) (wherein, the total of the above-mentioned polybutylene terephthalate (A) and the above-mentioned 4-methyl-1-pentene-α-olefin copolymer (B) is 100 parts by weight).

[0060] The resin composition (X) has the above-described structure, thus the resulting molded article exhibits excellent conformability and suppression of wrinkle formation. The reason for this is not yet clear, but the following mechanism can be presumed.

[0061] The resin composition (X) comprises specific amounts of polybutylene terephthalate (A) and a 4-methyl-1-pentene-α-olefin copolymer (B) satisfying specific requirements. Polybutylene terephthalate (A) and copolymer (B) are resins with different polarities, and it is presumed that the copolymer (B) is contained (dispersed) within the polybutylene terephthalate (A) in the composition. Essentially, regarding polybutylene terephthalate (A) and copolymer (B), it is presumed that the composition has an island-like structure with polybutylene terephthalate (A) as the continuous phase and copolymer (B) as the dispersed phase, and that the dispersed phase size of copolymer (B) is very small, making it easier to exhibit the stress-relieving properties characteristic of copolymer (B). Therefore, it is believed that the stress-relieving properties possessed by copolymer (B) are easily obtained. Therefore, the film formed from the resin composition (X) exhibits excellent conformability to differences in elevation (e.g., uneven shapes) and excellent suppression of wrinkle formation. Furthermore, when the molded body obtained from the above-mentioned resin composition (X) is used as a release film in the manufacture of FPC, it exhibits excellent conformability to fine height differences on the FPC and can also prevent adhesive from flowing out to the terminal portion.

[0062] The components of the resin composition (X) are described in detail below.

[0063] Polybutylene terephthalate (A)

[0064] The resin composition (X) comprises polybutylene terephthalate (A). Polybutylene terephthalate (A) is not particularly limited as long as it has structural units derived from 1,4-butanediol and structural units derived from terephthalic acid in its backbone; it can be polybutylene terephthalate (PBT) obtained by polycondensation of 1,4-butanediol and terephthalic acid, or it can contain other structural units besides those derived from 1,4-butanediol and terephthalic acid.

[0065] Examples of polybutylene terephthalate that include the other structural units mentioned above include block copolymers of polybutylene terephthalate and aliphatic polyethers, and block copolymers of polybutylene terephthalate and aliphatic polyesters.

[0066] From the viewpoint of obtaining a molded body with good dispersibility with the 4-methyl-1-pentene-α-olefin copolymer (B) described later, and with an excellent balance of conformability, wrinkle suppression, and mold release properties, polybutylene terephthalate (A) is preferably a condensation polymer of 1,4-butanediol and terephthalic acid (i.e., polybutylene terephthalate alone).

[0067] The monomers constituting polybutylene terephthalate (A) can be monomers derived from fossil fuels, monomers derived from biomass, or a combination of monomers derived from fossil fuels and monomers derived from biomass.

[0068] From the viewpoint of film-forming properties during film formation, the upper limit of the melt volume flow rate (MVR) of the above-mentioned polybutylene terephthalate (A) is preferably 40 cm⁻¹. 3 For 10 minutes or less, 35cm is more preferable. 3 / less than 10 minutes, further preferably 30cm 3 / less than 10 minutes. As a lower limit, 0.5cm is preferred. 3 / 10 minutes or more, preferably 2cm 3 / 10 minutes or more, further preferably 4cm 3 / 10 minutes or more.

[0069] It should be noted that the MVR was determined by measuring at a temperature of 250°C and a load of 2.16 kgf according to JIS K7210-1 (2014).

[0070] Furthermore, from the viewpoint of reducing critical surface tension, the upper limit of the melt volumetric flow rate (MVR) of the above-mentioned polybutylene terephthalate (A) is preferably 60 cm⁻¹. 3 / less than 10 minutes, preferably 50cm 3 / less than 10 minutes, further preferably 40cm 3 / Less than 10 minutes.

[0071] The preferred lower limit is 0.5 cm. 3 / 10 minutes or more, preferably 2cm 3 / 10 minutes or more, further preferably 4cm 3 / 10 minutes or more, preferably 15cm 3 / 10 minutes or more, preferably 25cm 3 / 10 minutes or more.

[0072] Furthermore, from the viewpoint of improving the smoothness of the film surface, the upper limit of the melt volume flow rate (MVR) of the above-mentioned polybutylene terephthalate (A) is preferably 60 cm⁻¹. 3 / less than 10 minutes, preferably 50cm 3 / less than 10 minutes, further preferably 40cm 3 / Less than 10 minutes.

[0073] The preferred lower limit is 0.5 cm. 3 / 10 minutes or more, preferably 2cm 3 / 10 minutes or more, further preferably 4cm 3 / 10 minutes or more, further preferably 15cm 3 / 10 minutes or more, preferably 25cm 3 / 10 minutes or more.

[0074] From the perspective of reducing critical surface tension or improving the smoothness of the film surface, the melt volumetric flow rate (MVR) of polybutylene terephthalate (A) is preferably in the range of 15 to 50 cm⁻¹. 3 Within a 10-minute range, more preferably within 25-40cm. 3 Within a 10-minute range.

[0075] From the viewpoint of film-forming properties in film forming, the melting point (Tm) of the above-mentioned polybutylene terephthalate (A) is preferably 180~250°C, more preferably 200~240°C, and even more preferably 210~230°C.

[0076] It should be noted that the melting point of polybutylene terephthalate (A) can be observed as follows: using a differential scanning calorimeter (DSC), the temperature is raised to 300°C and heated for 5 minutes to melt it. Then, the sample is quenched with liquid nitrogen to obtain the sample. Using 5 mg of the sample, the exothermic and endothermic curves are observed in a nitrogen gas flow at a heating rate of 10°C / min. The maximum temperature of the endothermic peak accompanying the melting is taken as the melting point (°C).

[0077] The aforementioned polybutylene terephthalate (A) can be synthesized or commercially available products can be used. Examples of commercially available products include those manufactured by Mitsubishi Chemical Co., Ltd. under the registered trademark "NOVADURAN", Toray Industries Co., Ltd. under the registered trademark "TORAYCON", Toyobo Co., Ltd. under the registered trademark "PLANAC", and Polyplastics Co., Ltd. under the registered trademark "DURANEX".

[0078] The content of polybutylene terephthalate (A) is 50-95 parts by mass, preferably 52-94 parts by mass, more preferably 56-93 parts by mass, and even more preferably 58-92 parts by mass (wherein, the total of the above-mentioned polybutylene terephthalate (A) and the 4-methyl-1-pentene-α-olefin copolymer (B) described below is 100 parts by mass).

[0079] Polybutylene terephthalate (A) can be used alone or in combination with two or more types.

[0080] <<4-Methyl-1-pentene-α-olefin copolymer (B)>>

[0081] The resin composition (X) of the present invention comprises a 4-methyl-1-pentene-α-olefin copolymer (B) that satisfies the following requirement (Ba) (hereinafter, sometimes simply referred to as "copolymer (B)").

[0082] [Requirement (Ba)]

[0083] It consists of 60-90 mol% of structural units (i) derived from 4-methyl-1-pentene and 10-40 mol% of structural units (ii) derived from α-olefins with 2-4 carbon atoms (wherein the total of structural units (i) and structural units (ii) is 100 mol%).

[0084] The content (molar %) values ​​of structural units (i) and (ii) in copolymer (B) were determined by carbon-13 nuclear magnetic resonance (hereinafter, sometimes referred to as "C13 NMR"). 13 The value is calculated using the C-NMR (C-NMR) measurement method. It should be noted that the specific measurement method is described in the examples below.

[0085] The content of the structural unit (i) is 60 to 90 mol%, preferably 65 to 89 mol%, more preferably 68 to 88 mol%, and even more preferably 70 to 87 mol%.

[0086] By ensuring that the content of structural unit (i) in copolymer (B) is 60 mol% or more, good dispersibility with polybutylene terephthalate resin (A) can be obtained, which is therefore preferred. Furthermore, when the content of structural unit (i) is within the above-mentioned range, the mold release properties of polybutylene terephthalate (A) are not impaired, thus the mold release properties of the film obtained from resin composition (X) are also excellent.

[0087] The content of structural unit (ii) is 10 to 40 mol%, preferably 11 to 35 mol%, more preferably 12 to 32 mol%, and even more preferably 13 to 30 mol%.

[0088] By making the content of structural unit (ii) in copolymer (B) 10 mol% or more, it is possible to further impart flexibility to the film containing resin composition (X).

[0089] Examples of α-olefins with 2 to 4 carbon atoms forming structural unit (ii) include ethylene, propylene, and 1-butene. One of these can be used alone, or two or more can be combined without prejudice to the invention.

[0090] Among them, propylene is particularly preferred as an α-olefin with 2 to 4 carbon atoms, which can achieve good dispersibility relative to polybutylene terephthalate (A) contained in the resin composition (X).

[0091] The 4-methyl-1-pentene and the α-olefin copolymer with 2 to 4 carbon atoms that constitute the 4-methyl-1-pentene-α-olefin copolymer (B) can be monomers derived from fossil fuels or from biomass, or a combination of monomers derived from fossil fuels and monomers derived from biomass.

[0092] The 4-methyl-1-pentene-α-olefin copolymer (B), in addition to requirement (Ba), preferably satisfies one or more requirements selected from the following requirements (Bb), (Bc), and (Bd), more preferably satisfies two or more requirements, and even more preferably satisfies three requirements. Furthermore, the 4-methyl-1-pentene-α-olefin copolymer (B), in addition to requirement (Ba), preferably satisfies at least one of the following requirements (Be) and (Bg).

[0093] [Requirement (Bb)]

[0094] The melting point (Tm) measured by differential scanning calorimetry (DSC) cannot be observed, or the melting point (Tm) measured by differential scanning calorimetry (DSC) is in the range of less than 160°C.

[0095] When the copolymer (B) has a melting point, the upper limit is preferably 150°C, more preferably 145°C, and even more preferably below 140°C.

[0096] The melting point values ​​described above vary depending on the stereoregularity of the copolymer (B) and the α-olefin of the structural unit (ii) polymerized with structural unit (i). The melting points described above can be adjusted to the desired composition using the α-olefin polymerization catalyst described later. It should be noted that the determination method is as described in the examples described later.

[0097] The release film obtained from the resin composition (X) exhibits excellent conformability to the fine contours (uneven shapes) of the FPC and also demonstrates excellent suppression of wrinkle formation. Further performance of these properties can be attributed to the stress-relieving properties of the copolymer (B).

[0098] Regarding stress mitigation, it can be evaluated, for example, by the loss tangent tanδ shown by the ratio of storage modulus G' to loss modulus G” (G” / G') determined by dynamic viscoelasticity. Storage modulus G' refers to the elastic component that stores this energy internally to maintain stress when stress is applied. Loss modulus G” is the viscous component that converts its energy into heat and releases it (diffusion to the outside) when stress is applied. Therefore, from the viewpoint that materials with higher loss tangent tanδ at a specific temperature environment are more likely to absorb impact and exhibit higher stress mitigation, copolymer (B) preferably satisfies the following requirements (Bc) and (Bd).

[0099] [Requirement (Bc)]

[0100] Within a temperature range of -40 to 150°C, the maximum value of the loss tangent tanδ (hereinafter sometimes referred to as the "tanδ peak value") obtained by dynamic viscoelasticity measurement based on torsion mode, frequency 1.0 Hz, heating rate 4°C / min, and strain setting 0.5% is preferably 0.5 to 5.0, more preferably 0.6 to 4.5, and even more preferably in the range of 0.7 to 4.0.

[0101] From the viewpoint that it can easily alleviate the stresses such as strain and deformation generated during compression molding in the FPC manufacturing process, the tanδ peak value of the copolymer (B) is preferably 1.0 or higher.

[0102] [Requirement (Bd)]

[0103] Within a temperature range of -40 to 150°C, the temperature at which the loss tangent tanδ reaches its maximum value (hereinafter, sometimes referred to as the "tanδ peak temperature"), determined by dynamic viscoelasticity measurements based on torsion mode, frequency 1.0 Hz, heating rate 4°C / min, and strain setting 0.5%, is -20 to 60°C, preferably -10 to 55°C, and more preferably 0°C to 50°C.

[0104] When the tanδ peak temperature of copolymer (B) alone is within the above-mentioned range, the resulting molded article exhibits an effect that easily mitigates stresses such as strain and deformation generated during compression molding in the FPC manufacturing process, and is therefore preferred. Specific measurement methods are described in the examples below.

[0105] It should be noted that the aforementioned tanδ peak value and tanδ peak temperature can be adjusted by the composition ratio of structural units (i) and (ii) in the copolymer (B). It should also be noted that the tanδ peak value and tanδ peak temperature of the copolymer (B) do not change significantly even when measured in a granular form containing, for example, a heat-resistant stabilizer.

[0106] In addition to requirement (Ba), the 4-methyl-1-pentene-α-olefin copolymer (B) preferably satisfies one or more requirements selected from requirements (Be), (Bf), and (Bg), more preferably two or more requirements, and even more preferably three requirements. Furthermore, in addition to requirements (Ba), (Be), (Bf), and (Bg), copolymer (B) may also satisfy at least one requirement selected from requirements (Bb), (Bc), and (Bd).

[0107] [Essentials (Be)]

[0108] In decahydronaphthalene solvent, the intrinsic viscosity [η] measured at 135°C is 0.5 to 5.0 dl / g, preferably 0.6 to 4.0 dl / g, and more preferably 0.8 to 3.0 dl / g.

[0109] When the intrinsic viscosity [η] of copolymer (B) is within the above range, the low-content component is less, thus reducing stickiness and making film forming easier, which is therefore preferred.

[0110] It should be noted that the specific method for measuring intrinsic viscosity [η] is as described in the examples below.

[0111] [Requirement (Bf)]

[0112] Density is 820~860 kg / m³ 3 The preferred value is 825~855 kg / m³. 3 More preferably, it is 830~850 kg / m 3 The range.

[0113] When the density of copolymer (B) is within the above range, it can impart flexibility to the film containing resin composition (X), which is therefore preferred.

[0114] It should be noted that the method for determining density is as described in the examples described later.

[0115] [Requirements (B~g)]

[0116] The ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), i.e., the molecular weight distribution (Mw / Mn), as determined by gel permeation chromatography (GPC), is 1.0 to 4.0, preferably 1.2 to 3.5, and more preferably in the range of 1.5 to 3.0.

[0117] If the molecular weight distribution (Mw / Mn) is below 4.0, the influence of low molecular weight polymers and low stereoregularity polymers from the composition distribution is less, and the release properties of the film containing the resin composition (X) are better.

[0118] Furthermore, the weight-average molecular weight (Mw) measured by gel permeation chromatography (GPC) and converted to polystyrene is preferably 500 to 10,000,000, more preferably 1,000 to 5,000,000, and even more preferably 5,000 to 2,500,000.

[0119] When the weight-average molecular weight (Mw) is within the above range, the membrane is easy to obtain moderate rigidity.

[0120] It should be noted that the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were determined by the measurement methods described in the examples below.

[0121] The content of copolymer (B) is 5 to 50 parts by mass, preferably 6 to 48 parts by mass, more preferably 7 to 44 parts by mass, and even more preferably 8 to 42 parts by mass (wherein, the total of polybutylene terephthalate (A) and copolymer (B) is 100 parts by mass).

[0122] When the content of copolymer (B) is within the above range, the film obtained from resin composition (X) exhibits excellent conformability to the fine height differences (uneven shape) of FPC and also has excellent heat resistance.

[0123] Copolymer (B) can be used alone or in combination with two or more types.

[0124] <Method for manufacturing copolymer (B)>

[0125] The method for manufacturing copolymer (B) is not particularly limited. For example, it can be manufactured by polymerizing 4-methyl-1-pentene with the aforementioned α-olefins having 2 to 4 carbon atoms in the presence of a suitable polymerization catalyst such as a magnesium-supported titanium catalyst or a metallocene catalyst.

[0126] Here, conventionally known catalysts can be appropriately used as polymerization catalysts, such as magnesium-supported titanium catalysts, metallocene catalysts described in International Publication No. 2001 / 53369, International Publication No. 2001 / 27124, Japanese Patent Application Publication No. 3-193796, or Japanese Patent Application Publication No. 2-41303, International Publication No. 2011 / 055803, International Publication No. 2014 / 050817, etc. Polymerization can be appropriately selected from liquid-phase polymerization methods including solution polymerization and suspension polymerization, as well as gas-phase polymerization methods.

[0127] In liquid-phase polymerization, non-reactive hydrocarbon solvents can be used as the solvents that constitute the liquid phase.

[0128] Examples of the aforementioned inert hydrocarbons include: aliphatic hydrocarbons containing propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene; alicyclic hydrocarbons containing cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons containing benzene, toluene, and xylene; and halogenated hydrocarbons containing dichloroethane, chlorobenzene, dichloromethane, trichloromethane, and tetrachloromethane; and mixtures thereof.

[0129] Alternatively, in liquid-phase polymerization, bulk polymerization can be carried out using the monomers corresponding to the aforementioned structural unit (i) derived from 4-methyl-1-pentene (i.e., 4-methyl-1-pentene) and the monomers corresponding to the aforementioned structural unit (ii) derived from α-olefins with 2 to 4 carbon atoms (i.e., the aforementioned α-olefins with 2 to 4 carbon atoms) themselves as solvents.

[0130] It should be noted that by copolymerizing the above-mentioned 4-methyl-1-pentene with the above-mentioned α-olefins with 2 to 4 carbon atoms in stages, the compositional distribution of the structural units (i) of 4-methyl-1-pentene and the structural units (ii) of α-olefins with 2 to 4 carbon atoms constituting copolymer (B) can also be appropriately adjusted.

[0131] The polymerization temperature for polymerizing copolymer (B) is preferably -50 to 200°C, more preferably 0 to 100°C, and even more preferably 20 to 100°C. The polymerization pressure for polymerizing copolymer (B) is preferably atmospheric pressure to 10 MPa gauge pressure, more preferably atmospheric pressure to 5 MPa gauge pressure.

[0132] During the polymerization of copolymer (B), hydrogen may be added to control the molecular weight and polymerization activity of the resulting polymer. Approximately 0.001 to 100 NL of hydrogen should be added per 1 kg of the total amount of 4-methyl-1-pentene and the α-olefin with 2 to 4 carbon atoms.

[0133] The resin composition (X) may further contain at least one elastomer selected from polyester elastomers (D) and styrene elastomers (E).

[0134] <<Polyester Elastomers (D)>>

[0135] Polyester-based elastomers (D) are preferably block copolymers whose hard segments (rigid) are composed of polyester components. In such block copolymers, it is common to use aromatic crystalline polyesters as the hard segments and polymers with low glass transition temperatures (Tg) as the soft segments (soft components).

[0136] It should be noted that polyester elastomers (D) can be appropriately designed by changing the type of polyester in the hard chain segment and / or the type of polymer in the soft chain segment.

[0137] Polyester elastomers (D) can be synthesized or commercially available products can be used.

[0138] Commercially available products include, for example, block copolymers of polyester components using polybutylene terephthalate as the hard segment and polytetramethylene ether glycol as the soft segment (i.e., polyester-polyether block copolymers), such as Hytrel (registered trademark) manufactured by Toray Celanese Co., Ltd., and PELPRENE P type (registered trademark) manufactured by Toyobo MC Co., Ltd.

[0139] Such polyester-polyether block copolymers achieve both excellent molding processability and low-temperature flexibility by using polybutylene terephthalate (PET) with excellent heat resistance in the hard segments and polytetramethylene ether glycol (PTG) with a low glass transition temperature (Tg) in the soft segments.

[0140] In addition, examples of polyester elastomers (D) include PELPRENE S type manufactured by Toyobo MC Co., Ltd., in which polybutylene terephthalate is used as the polyester component with hard segments and PELPRENE is used as the polyester component with soft segments.

[0141] Compared with the above-mentioned polyester-polyether block copolymers, such copolymers have better heat aging resistance and weather resistance.

[0142] It should be noted that polyester elastomers (D) can be used alone or in combination of two or more types.

[0143] Of these, from the viewpoint of superior compatibility with the aforementioned polybutylene terephthalate (A) and copolymer (B) as the polyester elastomer (D), a polyester-polyether block copolymer is preferred. Furthermore, when the resin composition (X) includes a polyester-polyether block copolymer, the crystallization rate of polybutylene terephthalate (A) can be delayed, reducing its crystallinity, thus improving the smoothness of the film surface, which is therefore preferable.

[0144] The melting point (Tm) of the polyester elastomer (D) is preferably 140~250°C, more preferably 150~240°C, and even more preferably 160~230°C. When the melting point of the polyester elastomer (D) is within the above range, it is particularly possible to obtain a film with good compatibility and heat resistance with polybutylene terephthalate (A), and therefore it is preferred.

[0145] Relative to 100 parts by weight of resin composition (X), the content of at least one elastomer selected from the group consisting of polyester elastomer (D) and styrene elastomer (E) described later is preferably 0 to 30 parts by weight, more preferably 0 to 25 parts by weight, further preferably 5 to 20 parts by weight, and most preferably 5 to 15 parts by weight. When the content of polyester elastomer (D) and / or styrene elastomer (E) is within the above range, the smoothness of the obtained film surface is improved, and the suppression of shrinkage in the resin film during T-die extrusion is more excellent.

[0146] <Styrene-based elastomers (E)>

[0147] There are no particular limitations on what constitutes a styrene-based elastomer (E). Examples include styrene-butadiene-styrene block copolymers (SBS), styrene-butadiene-butene-styrene block copolymers (SBBS), hydrogenated styrene-butadiene-styrene block copolymers (HBSR), styrene-ethylene-propylene-styrene block copolymers (SEPS), styrene-isoprene-styrene block copolymers (SIS), styrene-isobutylene-styrene block copolymers (SIBS), and styrene-isobutylene block copolymers (SIB).

[0148] It should be noted that styrene-based elastomers (E) can be used alone or in combination of two or more types.

[0149] Styrene-based elastomers (E) can be synthesized or commercially available products can be used. Commercially available styrene-based elastomers (E) include, for example, styrene-butadiene block copolymers (SBS) in which the butadiene component of the styrene-butadiene copolymer is hydrogenated and the styrene portion is copolymerized in the soft segment; SOE (registered trademark) manufactured by Asahi Kasei Corporation; Tufprene (registered trademark); DYNARON (registered trademark) manufactured by ENEOS Materials Co., Ltd.; Tuftec P series (registered trademark) manufactured by Asahi Kasei Corporation as styrene-butadiene-butene-styrene block copolymer (SBBS); Tuftec H series (registered trademark) manufactured by Asahi Kasei Corporation as styrene-ethylene-butene-styrene block copolymer (SEBS); Kraton G series (registered trademark) manufactured by Kraton Polymers Japan Co., Ltd.; and SIBSTAR (registered trademark) manufactured by Kaneka Co., Ltd. as styrene-isobutylene-styrene block copolymer (SIBS) and styrene-isobutylene block copolymer (SIB), etc.

[0150] The styrene content in the styrene-based elastomer (E) is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more and 50% by mass or less. When the styrene content is less than 2% by mass, the film obtained from the resulting resin composition (X) tends to be soft and the adhesion tends to be improved. On the other hand, when the styrene content is within the above-mentioned range, it is easy to obtain a film with moderate adhesion, and the conformability and wrinkle suppression of the molded body obtained from the resin composition (X) are more excellent.

[0151] The styrene-based elastomer (E) can be an unmodified styrene-based elastomer, or it can be a styrene-based elastomer modified with at least one functional group selected from the group consisting of anhydride, carboxyl, amino, imino, alkoxy, silanol, silyl ether, hydroxyl and epoxy groups.

[0152] From the viewpoint that polybutylene terephthalate (A) with high polarity has better compatibility with copolymer (B), styrene-based elastomer (E) is preferably a styrene-based elastomer obtained by modifying maleic anhydride (maleic anhydride modified styrene-based elastomer).

[0153] Maleic anhydride modified styrene elastomers can be commercially available products. Examples of commercially available products include the Tuftec M series (registered trademark) manufactured by Asahi Kasei Corporation and the Kraton FG polymer (registered trademark) manufactured by Kraton Polymers Japan Corporation.

[0154] <Resin Composition (X)>

[0155] The resin composition (X) comprises, in the range of 50-95 parts by weight, preferably 52-94 parts by weight, more preferably 56-93 parts by weight, and even more preferably 58-92 parts by weight, polybutylene terephthalate (A) and, in the range of 5-50 parts by weight, preferably 6-48 parts by weight, more preferably 7-44 parts by weight, and even more preferably 8-42 parts by weight, a 4-methyl-1-pentene-α-olefin copolymer (B) satisfying the aforementioned requirement (Ba) (wherein, the total of polybutylene terephthalate (A) and copolymer (B) is set to 100 parts by weight).

[0156] [Method for manufacturing resin composition (X)]

[0157] The resin composition (X) is obtained by mixing polybutylene terephthalate (A) and copolymer (B) in the specific proportions described above. There are no particular limitations on the mixing method, and various known methods can be cited, such as dry mixing of the above components using a Henschel mixer, drum mixer, V-type mixer, etc.; melt mixing followed by melt mixing using a single-screw extruder, twin-screw extruder, Banbury mixer, etc.; and stirring mixing in the presence of a solvent, etc.

[0158] The resin composition (X) may contain components other than polybutylene terephthalate (A), copolymer (B), polyester elastomer (D) and styrene elastomer (E) (hereinafter referred to as "other components") without impairing the effects of the present invention.

[0159] Other components include, for example, antioxidants, antistatic agents, surfactants, fibers, inorganic or organic fillers, ultraviolet absorbers, nucleating agents, pigments, hydrochloric acid absorbers, crosslinking agents, crosslinking aids, softeners, flame retardants, and various additives, as well as resins other than polybutylene terephthalate (A), copolymers (B), polyester elastomers (D), and styrene elastomers (E).

[0160] As antioxidants, known antioxidants can be used. Specifically, hindered phenolic compounds, sulfur-based antioxidants, lactone-based antioxidants, organophosphite compounds, organophosphonate compounds, or compounds combining several of them can be used. Examples include phenolic compounds (such as 2,6-di-tert-butyl-4-methylphenol), polycyclic phenolic compounds (such as 2,2'-methylenebis(4-methyl-6-tert-butylphenol)), phosphorus-based compounds (such as tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenyl diphosphonate), and amine-based compounds (such as N,N-diisopropyl-p-phenylenediamine).

[0161] There are no particular limitations on what can be used as an antistatic agent; examples include surfactants, fatty acid esters, and polymeric antistatic agents, which will be discussed later. Examples of fatty acid esters include stearic acid and oleic acid esters, while examples of polymeric antistatic agents include polyether ester amides.

[0162] There are no particular limitations on the types of surfactants that can be used; for example, nonionic, anionic, cationic, or amphoteric surfactants can be included. Examples of nonionic surfactants include polyethylene glycol-type nonionic surfactants such as ethylene oxide adducts of higher alcohols, ethylene oxide adducts of fatty acids, ethylene oxide adducts of higher alkylamines, and ethylene oxide adducts of polypropylene glycol; fatty acid esters of polyethylene oxide and glycerol; fatty acid esters of pentaerythritol; fatty acid esters of sorbitol or sorbitan anhydride; alkyl ethers of polyols; and aliphatic amides of alkanolamines. Examples of anionic surfactants include sulfate salts of alkali metals of higher fatty acids, sulfonates such as alkylbenzene sulfonates, alkyl sulfonates, and sulfonates such as alkanes; and phosphate salts such as phosphate salts of higher alcohols. Examples of cationic surfactants include quaternary ammonium salts such as alkyl trimethylammonium salts. Examples of amphoteric surfactants include amino acid-type amphoteric surfactants such as higher alkyl aminopropionates, and betaine-type amphoteric surfactants such as higher alkyl dimethyl betaine and higher alkyl dihydroxyethyl betaine.

[0163] Relative to a total of 100 parts by weight of polybutylene terephthalate resin (A), copolymer (B), polyester elastomer (D) and styrene elastomer (E) in the resin composition (X), the content of other components is preferably 5 parts by weight or less, more preferably 4 parts by weight or less, and even more preferably 2 parts by weight or less.

[0164] In addition, the content of resins other than polybutylene terephthalate resin (A), copolymer (B), polyester elastomer (D) and styrene elastomer (E) is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, further preferably 5 parts by weight, particularly preferably 1 part by weight or less, and most preferably substantially none, relative to a total of 100 parts by weight of polybutylene terephthalate resin (A), copolymer (B), polyester elastomer (D) and styrene elastomer (E).

[0165] <Molded Body>

[0166] The molded article of the present invention comprises the above-described resin composition (X). The molded article can be manufactured into a desired shape by conventionally known molding methods, such as hot pressing, compression molding, injection molding, and extrusion molding. In the case of injection molding, the molded article can be manufactured using a desired mold.

[0167] The shape of the molded body is not particularly limited, and can be any shape such as sheet, film, plate, cylinder, and prism. However, from the viewpoint of excellent demolding properties, conformability, and suppression of wrinkle formation, a film shape is preferred as the shape of the molded body.

[0168] <membrane>

[0169] The membrane of the present invention comprises the above-described resin composition (X), preferably composed of the above-described resin composition (X).

[0170] The membrane can be a single-layer membrane, or a multilayer membrane formed by stacking a layer containing the above-described resin composition (X) with other layers, or a multilayer membrane formed by stacking multiple layers containing the above-described resin composition (X).

[0171] There are no particular limitations on the uses of the film; examples include protective films, cosmetic films, shrink films, hot melt films, and release films. Among these, from the viewpoint of excellent release properties, conformability, and wrinkle suppression, it can be appropriately used as a release film.

[0172] There are no particular limitations on the type of release film. Examples include release films for flexible printed wiring substrates (FPC), ACM substrates, rigid substrates, rigid-flexible wiring substrates, front-end composite materials, fiber-reinforced composite material manufacturing processes, carbon fiber composite material curing, carbon fiber composite material molding, glass fiber composite material curing, glass fiber composite material molding, aramid fiber composite material curing, and aramid fiber composite material. Release films for various applications, including: release films for molding materials, release films for curing nanocomposite materials, release films for curing filler materials, release films for semiconductor sealing, release films for polarizing plates, release films for diffusers, release films for prism sheets, release films for reflective sheets, release films for buffer films, release films for fuel cells, release films for various rubber sheets, release films for curing urethanes, release films for curing epoxy resins, release films for silicone resins, release films for LED sealant molds, release films for acrylic adhesives, release films for protective films, and release films for synthetic leather.

[0173] In addition, release films can also be used for release papers such as synthetic leather release paper, front-end composite material release paper, carbon fiber composite material curing release paper, glass fiber composite material curing release paper, aramid fiber composite material curing release paper, nano composite material curing release paper, filler material curing release paper, heat-resistant and water-resistant photo paper, etc.

[0174] <Membrane Manufacturing Methods>

[0175] There are no particular restrictions on the manufacturing method of the membrane; well-known methods such as extrusion casting and extrusion lamination can be used.

[0176] The following describes an example of a method for manufacturing a membrane, but the method for manufacturing a membrane according to the present invention is not limited thereto.

[0177] First, material for the aforementioned resin composition (X) is fed into an extrusion molding machine connected to a T-die. Then, the cylinder temperature is set to 240-260°C and the T-die temperature is set to 240-250°C to melt the resin. This molding machine can be a single-screw extruder or a twin-screw extruder.

[0178] Molten resin is extruded through a T-die and then cooled and cured at a casting roller temperature of 50~80℃, thereby obtaining a single-layer release film.

[0179] There are no particular limitations on the thickness of the film, which can be determined appropriately as needed. The thickness of the release film is usually 10~300μm, preferably 15~250μm, and more preferably in the range of 20~200μm.

[0180] When the film thickness is 10 μm or more, it is easy to handle due to its moderate rigidity and is not prone to breakage during peeling. Furthermore, when the thickness of the release film is 300 μm or less, it is beneficial for the film to be lightweight and to follow the contours of the FPC (e.g., uneven shapes).

[0181] <Membrane Properties>

[0182] The critical surface tension of the membrane at 23°C is preferably 20~30 mN / m. The value of the critical surface tension indicates the release properties of the membrane surface. The smaller the value of the critical surface tension, the better the release properties.

[0183] The critical surface tension of the membrane is more preferably 21~29 mN / m, and even more preferably 22~28 mN / m.

[0184] If the critical surface tension of the film is within the above range, it exhibits excellent release properties. When the film is used as a release film for flexible printed wiring substrates (FPC), it is preferred because it prevents defects such as the film from sticking to the FPC and cracking, or the FPC's circuitry from peeling off during the pressing and molding process of the FPC, from occurring.

[0185] As a method for determining the critical surface tension mentioned above, a calculation method based on the Zisman plot can be cited as an example.

[0186] In the Zisman plot-based calculation method, the contact angles of solids with different surface tensions for various liquids are measured. When the surface tensions of each liquid are plotted on the horizontal axis and the measured contact angles (cosθ) of the solid are plotted on the vertical axis, a direct relationship can be obtained. Extrapolating from this line to cosθ=1.0, which is considered a fully wetted state, the critical surface tension (mN / m) of the solid can be calculated from the intersection with this horizontal axis.

[0187] It should be noted that the details of the determination conditions for critical surface tension, etc., are as described in the examples described later.

[0188] The storage modulus E' of the solid viscoelasticity at 180°C, measured under stretching conditions, frequency 1.0 Hz, heating rate 3°C / min, and strain 0.1%, is preferably in the range of 10 to 90 MPa, more preferably in the range of 12 to 88 MPa, even more preferably in the range of 15 to 85 MPa, and particularly preferably in the range of 20 to 80 MPa.

[0189] It should be noted that the specific method for determining the storage modulus E' of solid viscoelasticity is as described in the examples described later.

[0190] When the above-mentioned film is used as a release film for flexible printed wiring substrates (FPC), by keeping the storage modulus E' of the solid viscoelasticity of the film at 180°C within the above-mentioned range, it can alleviate the stresses such as strain and deformation generated during the pressing and molding process of FPC. Therefore, it has excellent conformability to the height difference (e.g., uneven shape) of FPC, can prevent adhesive from flowing into the terminal part, reduce wrinkles, and has excellent release properties.

[0191] If the storage modulus E' of the solid viscoelasticity at 180℃ is above 10MPa, then the heat resistance at high temperature is also excellent, and it can be used as a release film for printed circuit board manufacturing process.

[0192] In addition, when the storage modulus E' of the solid viscoelasticity at 180°C is below 90 MPa, the film has moderate rigidity, thus exhibiting excellent conformability to the fine height differences (undulations) of the FPC and suppressing the flow of adhesive to the terminal portion.

[0193] The maximum value of the loss tangent tanδ of the solid viscoelasticity at 20-35°C (hereinafter sometimes referred to as the "tanδ peak value"), measured under the conditions of stretching mode, frequency 1.0 Hz, heating rate 3°C / min, and strain 0.1%, is preferably in the range of 0.02-0.30, more preferably in the range of 0.022-0.29, and even more preferably in the range of 0.024-0.28.

[0194] It should be noted that the method for determining the tanδ peak value is as described in the examples described later.

[0195] When the peak value of the loss tangent tanδ of the solid viscoelasticity at 20~35°C, measured under stretching mode, frequency 1.0Hz, heating rate 3°C / min, and strain 0.1%, is within the above range, especially when used as a release film for flexible printed wiring substrates (FPC), it exhibits excellent conformability to the height difference (undulation) of the FPC from the initial stage of pressurization in the FPC manufacturing process. Even if the FPC has unevenness, the adhesive applied to the cover layer is not easily seeped out due to heating and pressurization, and the opening hole exposed by the copper foil can be easily ensured as desired, which is preferred.

[0196] [Example]

[0197] The present invention will now be described in more detail based on embodiments, but the present invention is not limited to these embodiments.

[0198] The methods for determining the physical properties of the resin, the resin used, the method for preparing the test pieces, and the evaluation methods in the following examples and comparative examples are described below.

[0199] <<Methods for Determining the Physical Properties of Polymers>>>

[0200] <Content of structural units>

[0201] The amount of structural units derived from 4-methyl-1-pentene and the amount of structural units derived from α-olefins contained in copolymer (B) are determined by the following apparatus and conditions. 13 The results were calculated using C-NMR spectroscopy. The amount of structural units derived from α-olefins in this determination does not include the amount of structural units derived from 4-methyl-1-pentene.

[0202] Using a nuclear magnetic resonance (NMR) apparatus (JEOL Ltd., model: ECP500), the following procedures were followed: o-dichlorobenzene / deuterated benzene (80 / 20 volume %) mixed solvent, sample concentration 55 mg / 0.6 mL, measurement temperature 120 °C, and observation of nuclei... 13 The sequence was determined using a single-pulse proton decoupling method (C125 MHz), with a pulse width of 4.7 μs (45° pulse), a repetition time of 5.5 seconds, and a cumulative count exceeding 10,000. 27.50 ppm was used as the reference value for chemical shift. The obtained... 13 C-NMR spectroscopy quantifies the composition of copolymer (B).

[0203] Intrinsic viscosity (η)

[0204] The intrinsic viscosity of copolymer (B) was determined using an Ubbelohde viscometer in a decahydronaphthalene solvent at 135°C. Approximately 20 mg of sample was collected for each copolymer (B). The sample could be in the form of polymer powder, granules, or resin blocks. The copolymer was dissolved in 15 mL of decahydronaphthalene, and the specific viscosity ηsp was measured in an oil bath heated to 135°C. The solution was then diluted with 5 mL of decahydronaphthalene solvent, and the specific viscosity ηsp was measured again. This dilution was repeated twice more, and the value of ηsp / C, extrapolated to zero from the concentration (C), was calculated as the limiting viscosity (η) (refer to the following formula).

[0205] [η]=lim(ηsp / C)(C→0)

[0206] <Weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn)>

[0207] The molecular weight of copolymer (B) was determined by gel permeation chromatography (GPC).

[0208] Specifically, a Waters ALC / GPC150-Cplus liquid chromatograph (differential refractometer and detector integrated) was used. Two GMH6-HT and two GMH6-HTL columns from Tosoh Corporation were connected in series as the separation column. o-Dichlorobenzene was used as the mobile phase, and 0.025% by mass dibutylhydroxytoluene (manufactured by Takeda Pharmaceutical Company Limited) was used as the antioxidant. The mobile phase was moved at a rate of 1.0 mL / min, the sample concentration was 15 mg / 10 mL, and the sample injection volume was 500 μL. A differential refractometer was used as the detector. For the standard polystyrene, Tosoh Corporation's standard polystyrene was used when the weight-average molecular weight (Mw) was 1,000 or higher and 4,000,000 or lower.

[0209] For the obtained chromatograms, a standard curve was constructed using standard polystyrene samples using known methods and analyzed to calculate the weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn). The determination time for each sample was 60 minutes.

[0210] Melt Flow Rate (MFR)

[0211] The MFR of copolymer (B) was determined according to ASTM D1238 at a temperature of 230°C and a load of 2.16 kgf.

[0212] Melting point (Tm)

[0213] The melting point (Tm) of copolymer (B) was determined according to JIS K7121 using a differential scanning calorimeter (DSC200, manufactured by Hitachi High Technology Co., Ltd.). Approximately 5 mg of sample was placed in the aluminum pan for measurement, and the temperature was increased to 200°C at a rate of 10°C / min. The temperature of the highest melting peak among the measured melting peaks was taken as the melting point. If no melting peak was observed, it was considered that no melting point was observed.

[0214] <Density>

[0215] The density of copolymer (B) was determined using a density gradient tube according to JIS K7112.

[0216] Polybutylene terephthalate (A-1)

[0217] As polybutylene terephthalate (A-1), it is manufactured by Mitsubishi Chemical Co., Ltd., product name: NOVADURAN5010R (MVR=21cm). 3 / 10 minutes (250℃, 2.16kgf, melting point 224℃).

[0218] During film forming, the granules of polybutylene terephthalate (A-1) are dried in a hot air dryer at 120°C for 5 hours.

[0219] Polybutylene terephthalate (A-2)

[0220] As polybutylene terephthalate (A-2), it is manufactured by Mitsubishi Chemical Co., Ltd., product name: NOVADURAN5010R5 L2 (MVR=35cm). 3 / 10 minutes (250℃, 2.16kgf, melting point 224℃).

[0221] During film forming, the granules of polybutylene terephthalate (A-2) are dried in a hot air dryer at 120°C for 5 hours.

[0222] <Synthesis of Copolymer (B)>

[0223] As copolymers (B), two copolymers (B-1) and copolymer (B-2) with different ratios of structural units (i) derived from 4-methyl-1-pentene and structural units (ii) derived from α-olefins with 2 to 4 carbon atoms were synthesized according to the following synthesis method.

[0224] <Synthesis Example 1: Synthesis of Copolymer (B-1)>

[0225] In a 1.5 L SUS autoclave equipped with a stirrer and fully purged with nitrogen, 300 mL of n-hexane (the product dried on activated alumina under a dry nitrogen atmosphere) and 450 mL of 4-methyl-1-pentene were added at 23 °C. Then, 0.75 mL of a 1.0 mmol / mL toluene solution of triisobutylaluminum (TIBAL) was added to the autoclave and stirred.

[0226] Next, the autoclave was heated to an internal temperature of 60°C and pressurized with propylene at a total pressure (gauge pressure) of 0.40 MPa. Then, 0.34 mL of a pre-prepared toluene solution containing 1 mmol of methylaluminoxane (converted to aluminum) and 0.01 mmol of diphenylmethylene (1-ethyl-3-tert-butylcyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride was introduced into the autoclave under nitrogen pressure to initiate the polymerization reaction. During the polymerization reaction, the temperature was adjusted to maintain an internal temperature of 60°C in the autoclave. Sixty minutes after the start of polymerization, 5 mL of methanol was introduced into the autoclave under nitrogen pressure to stop the polymerization reaction, and then the pressure inside the autoclave was released to atmospheric pressure. After depressurization, acetone was added to the reaction solution while stirring.

[0227] The obtained solvent-containing powdered copolymer was dried at 100°C under reduced pressure for 12 hours. The mass of the copolymer (B-1) as the product was 36.9 g. In copolymer (B-1), the amount of structural units derived from 4-methyl-1-pentene was 72.4 mol%, and the content of structural units (i) derived from propylene was 27.6 mol%. DSC determination was performed, and no melting point was observed.

[0228] The results of the determination of the properties of the obtained copolymer (B-1) are shown in Table 1.

[0229] <<Preparation of Granules>>

[0230] Next, relative to 100 parts by weight of the copolymer (B-1), 1000 ppm of pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionic acid] as a heat stabilizer and 1000 ppm of tris(2,4-di-tert-butylphenyl) phosphate as a secondary antioxidant were added. The extruded material was discharged using a twin-screw extruder (manufactured by Nippon Steel Co., Ltd., model: TEX25αIII, screw diameter 25mm, L / D=52) under the conditions of barrel temperature set at 200°C, extrusion rate of 5kg / hour and screw speed of 100rpm. While being immersed in a water tank, the material was guided to a granulator (manufactured by KATSUMIX Co., Ltd., model: KM-100) for granulation to prepare granules containing copolymer (B-1).

[0231] <Synthesis Example 2: Synthesis of Copolymer (B-2)>

[0232] In a 1.5 L SUS autoclave equipped with a stirrer and fully purged with nitrogen, 300 mL of n-hexane (the product dried on activated alumina under a dry nitrogen atmosphere) and 450 mL of 4-methyl-1-pentene were added at 23 °C. Then, 0.75 mL of a 1.0 mmol / mL toluene solution of triisobutylaluminum (TIBAL) was added to the autoclave and stirred.

[0233] Next, the autoclave was heated to an internal temperature of 60°C and pressurized with propylene at a total pressure (gauge pressure) of 0.19 MPa. Then, 0.34 mL of a pre-prepared toluene solution containing 1 mmol of methylaluminoxane (converted to aluminum) and 0.01 mmol of diphenylmethylene (1-ethyl-3-tert-butylcyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride was introduced into the autoclave under nitrogen pressure to initiate the polymerization reaction. During the polymerization reaction, the temperature was adjusted to maintain an internal temperature of 60°C in the autoclave. Sixty minutes after the start of polymerization, 5 mL of methanol was introduced into the autoclave under nitrogen pressure to stop the polymerization reaction, and the pressure inside the autoclave was released to atmospheric pressure. After depressurization, acetone was added to the reaction solution while stirring.

[0234] The obtained solvent-containing powdered polymer was dried at 130°C under reduced pressure for 12 hours. The mass of the copolymer (B-2) as the product was 44.0 g. In the copolymer (B-2), the content of structural units (i) derived from 4-methyl-1-pentene was 84.1 mol%, and the content of structural units (ii) derived from propylene was 15.9 mol%. DSC determination showed that the melting point was 130°C.

[0235] The results of the determination of the properties of the obtained copolymer (B-2) are shown in Table 1.

[0236] <<Preparation of Granules>>

[0237] Next, relative to 100 parts by weight of the copolymer (B-2), 1000 ppm of pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionic acid] as a heat stabilizer and 1000 ppm of tris(2,4-di-tert-butylphenyl) phosphate as a secondary antioxidant were added. The extruded material was discharged using a twin-screw extruder (manufactured by Nippon Steel Co., Ltd., model: TEX25αIII, screw diameter 25mm, L / D=52) under the conditions of barrel temperature set at 200°C, extrusion rate of 5kg / hour and screw speed of 100rpm. While being immersed in a water tank, the material was guided to a granulator (manufactured by KATSUMIX Co., Ltd., model: KM-100) for granulation to prepare granules containing copolymer (B-2).

[0238] <Determination of Dynamic Viscoelasticity>

[0239] The copolymers (B-1) and (B-2) obtained by the above method were filled into SUS molds in predetermined amounts. The heating plate was set to 200°C, and a hydraulic hot press (manufactured by Shinto Metal Industry Co., Ltd., model: NSF-50) was used for preheating for 7 minutes, followed by pressing at 10 MPa gauge pressure for 2 minutes. The press was then transferred to a cooling plate set to 20°C and compressed and cooled at 10 MPa gauge pressure for 2 minutes to produce a 2 mm thick measuring tablet.

[0240] Next, for the 2 mm thick test pellet obtained by the above method, the dynamic viscoelastic temperature dispersion in the range of -40 to 150 °C was observed using a rheometer (Anton Paar, model: MCR301) under the conditions of torsion mode, frequency 1.0 Hz, heating rate 4 °C / min, and strain 0.5%. The peak tanδ and peak tanδ temperature were measured. The results are shown in Table 1.

[0241] [Table 1]

[0242]

[0243] <Example 1>

[0244] The resin composition (X) is prepared by mixing 90 parts by weight of polybutylene terephthalate (A-1) and 10 parts by weight of the granules containing copolymer (B-1) prepared above using a rotary drum mixer (dry mixing).

[0245] [Making of release film]

[0246] Next, the resin composition (X-1) prepared above is fed into the raw material hopper of a single-screw extruder (screw diameter 20mm, L / D=24, T-die width 300mm, die lip opening 2mm) equipped with a T-die.

[0247] The barrel temperature is set to 240~250℃, the T-die temperature is set to 250℃, molten resin is extruded from the T-die while the casting roller temperature is set to 60℃ and the traction speed is set to 0.8m / min, and a single-layer film thickness of 50μm is formed to obtain a release film.

[0248] During film production, the film surface that initially comes into direct contact with the casting roller is designated as the demolding surface, and the other film surface is designated as the back surface.

[0249] The film-forming properties, release film properties, and compression molding evaluation were performed using the methods described below. The results are shown in Table 2.

[0250] [Film-forming properties]

[0251] Using the same molding machine as described above for "preparation of the release film," namely a single-screw extruder equipped with a T-die (300 mm wide), and setting the same barrel temperature and T-die temperature, the screw speed was adjusted to an extrusion rate of 5 kg / hour. The molten resin discharged from the T-die flowed directly down in a vertical direction, and the film width (width of the resin film) was measured at a position 50 mm below the die lip of the T-die.

[0252] The efficiency of the film-forming width is calculated using the following formula. It can be said that the higher the efficiency of the film-forming width, the better the shrinkage phenomenon can be suppressed.

[0253] Effectiveness of film-forming width (%) = {1 - {(T-die width) - (measured value of film-forming width)} / (T-die width)} × 100

[0254] Surface roughness

[0255] For the release surface of the release film prepared by the above method, the arithmetic mean roughness (Ra) was measured in the MD direction (machine direction of resin flow) and the TD direction (transverse direction of resin flow) according to JIS B0601, under the conditions of a probe of 2 μm, a measuring length of 4.0 mm, a cutoff wavelength of 0.8 mm, and a measuring speed of 0.15 mm / s. The results are shown in Table 2.

[0256] [Critical surface tension]

[0257] For the release surface of the release film prepared by the above method, in order to evaluate the critical surface tension, a wetting tension test solution (manufactured by Fujifilm and Kohden Chemical Co., Ltd.) of ethylene glycol monoethyl ether / formamide mixture with a surface tension adjusted to 31 mN / m, 34 mN / m, 37 mN / m and 40 mN / m respectively was dropped onto the surface of the film under an atmosphere of 23°C and 50% relative humidity.

[0258] Next, the contact angle was measured using an image processing-based solid-liquid interface analysis system (Kyowa Interface Science Co., Ltd., model: DropMaster500). Using the Zisman plot method, a graph was plotted with the surface tension of the mixture on the x-axis and the measured contact angle (converted to radians and set as cosθ) on the y-axis, yielding a linear function using the least squares method. This linear function graph was extrapolated to a state considered fully wetted at cosθ=1.0, and the surface tension at which cosθ=1.0 on the graph (i.e., the x-axis value at the point on the graph where cosθ=1.0) was calculated as the critical surface tension (mN / m). The results are shown in Table 2.

[0259] [Storage modulus E' at 180℃]

[0260] The release film, prepared using the above method and cut into strips along the MD direction, was used as test pieces. Using a rheometer (TA Instruments, model RSA-G2), the storage modulus E' of the solid viscoelasticity observed through temperature dispersion from -50 to 200°C at 180°C was determined under the conditions of tensile mode, frequency 1.0 Hz, heating rate 3°C / min, and strain 0.1%. The results are shown in Table 2.

[0261] [Peak value of loss tangent tanδ at 20~35℃]

[0262] The release film, prepared by the above method and cut into strips along the MD direction, was used as a test piece. The tanδ peak temperature and tanδ peak value of the loss tangent tanδ (represented by the ratio of loss modulus E” to storage modulus E’ (E” / E’) at 20~35℃ were determined in the same manner as the solid viscoelasticity observed by the above method.

[0263] [Evaluation of the compression molding of release film]

[0264] Prepare flexible copper clad laminates (FCCLs) and evaluate the release properties, conformability, and wrinkle resistance of the release film using a rapid pressing molding device.

[0265] [Demolding properties]

[0266] Prepare a flexible copper-clad laminate (100mm width × 200mm length, conductor width L = 100μm / conductor gap S = 100μm, polyimide thickness 25μm, copper foil thickness 35μm) and a cover film (100mm width × 200mm length, polyimide thickness 25μm, epoxy adhesive layer thickness 35μm) with a Φ1.0mm opening. Lay the flexible copper-clad laminate together with the epoxy adhesive layer of the cover film.

[0267] Next, the release film and the cover film are overlapped and stacked together, and then heated and pressed under conditions of 180°C, 3.0MPa, vacuum for 5 seconds and pressurization for 2 minutes to form a laminate.

[0268] After the laminate is removed from the press, a small gap is made at the end of the release film so that the end of the laminate becomes the starting point for peeling, and then it is placed on the platform.

[0269] The time required for the release film to completely peel off from the laminate was measured, and the release performance was evaluated according to the following evaluation criteria. When the evaluation criterion is A, the release performance can be considered excellent.

[0270] -Evaluation Criteria-

[0271] A: It takes less than 60 seconds from the start of the peeling process to its completion.

[0272] B: The time from the start of peeling to its completion is more than 60 seconds but less than 90 seconds.

[0273] C: The time from the start of peeling to the completion of peeling takes more than 90 seconds. Or, the release film did not peel off.

[0274] [Following]

[0275] Prepare a flexible copper-clad laminate (100mm width × 200mm length, conductor width L = 100μm / conductor gap S = 100μm, polyimide thickness 25μm, copper foil thickness 35μm) and a cover film (100mm width × 200mm length, polyimide thickness 25μm, epoxy adhesive layer thickness 35μm) with a Φ1.0mm opening. Lay them together with the copper foil side of the flexible copper-clad laminate in contact with the epoxy adhesive layer side of the cover film.

[0276] Next, the release film is laminated with the cover film in contact with the release surface of the release film. The laminate is then heated and pressed under conditions of 180°C, 3.0MPa, vacuum for 5 seconds, and pressurization for 2 minutes to form the laminate.

[0277] Then, the release film was peeled off, and the epoxy adhesive flowing into the upper surface (copper foil side) of the flexible copper-clad laminate was observed using an optical microscope. The flow width (exudation width) of the epoxy adhesive at 10 points was measured, and its arithmetic mean was calculated. The followability of the release film was evaluated according to the following evaluation criteria. It can be seen that the smaller the average flow width of the epoxy adhesive, the more the outflow of the adhesive is suppressed, and the better the followability to height differences. That is, when the evaluation criterion is A, the followability can be said to be excellent.

[0278] -Evaluation Criteria-

[0279] A: The average inflow width of the epoxy adhesive is less than 55 μm.

[0280] B: The average inflow width of the epoxy adhesive is over 55 μm.

[0281] [Anti-wrinkle properties (inhibition of wrinkle formation)]

[0282] Prepare a flexible copper-clad laminate (100mm width × 200mm length, conductor width L = 100μm / conductor gap S = 100μm, polyimide thickness 25μm, copper foil thickness 35μm) and a cover film (100mm width × 200mm length, polyimide thickness 25μm, epoxy adhesive layer thickness 35μm) with a Φ1.0mm opening. Lay the flexible copper-clad laminate together with the epoxy adhesive layer of the cover film.

[0283] Next, the release film is laminated with the cover film in contact with the release surface of the release film. The laminate is then heated and pressed under conditions of 180°C, 3.0MPa, vacuum for 5 seconds, and pressurization for 2 minutes to form the laminate.

[0284] After removing the laminate from the press, peel off the release film and visually inspect the surfaces of the release film and the flexible copper-clad laminate / cover film. Evaluate the wrinkle resistance of the release film according to the following evaluation criteria. When the evaluation criterion is A, the wrinkle resistance can be considered excellent.

[0285] -Evaluation Criteria-

[0286] A: No wrinkles were found in the release film, flexible copper-clad laminate, or cover film.

[0287] B: Wrinkles can be identified on the release film, and wrinkles are also transferred onto the flexible copper-clad laminate and / or cover film.

[0288] <Example 2>

[0289] As components of the resin composition (X), 80 parts by weight of polybutylene terephthalate (A-1) and 20 parts by weight of granules containing copolymer (B-1) were used. Otherwise, the resin composition (X) was prepared in the same manner as in Example 1. A release film was then made from this composition, and the film-forming properties, physical properties of the release film, and compression molding were evaluated. The results are shown in Table 2.

[0290] <Example 3>

[0291] As components of resin composition (X), 80 parts by weight of polybutylene terephthalate (A-1) and 20 parts by weight of granules containing copolymer (B-2) were used. Otherwise, resin composition (X) was prepared in the same manner as in Example 1. A release film was then made from this composition, and its film-forming properties, physical properties of the release film, and compression molding performance were evaluated. The results are shown in Table 2.

[0292] <Example 4>

[0293] As components of resin composition (X), 60 parts by weight of polybutylene terephthalate (A-1) and 40 parts by weight of granules containing copolymer (B-1) were used. Otherwise, resin composition (X) was prepared in the same manner as in Example 1. A release film was then made from this composition, and its film-forming properties, physical properties of the release film, and compression molding properties were evaluated. The results are shown in Table 2.

[0294] <Example 5>

[0295] As components of the resin composition (X), 60 parts by weight of polybutylene terephthalate (A-1) and 40 parts by weight of granules containing copolymer (B-2) were used. Otherwise, the resin composition (X) was prepared in the same manner as in Example 1. A release film was then made from this composition, and the film-forming properties, physical properties of the release film, and compression molding were evaluated. The results are shown in Table 2.

[0296] <Example 6>

[0297] As a component of the resin composition (X), 10 parts by mass of polyester elastomer (D) (Hytrel 7247 manufactured by Toray Celanese Co., Ltd.: melting point (Tm) 216°C) were used, relative to a total of 100 parts by mass of 90 parts by mass of polybutylene terephthalate (A-1) and 10 parts by mass of granules containing copolymer (B-1). Otherwise, the resin composition (X) was prepared in the same manner as in Example 1, and a release film was made from this composition. The film-forming properties, physical properties of the release film, and compression molding were evaluated. The results are shown in Table 2.

[0298] <Example 7>

[0299] As a component of the resin composition (X), in addition to 90 parts by mass of polybutylene terephthalate (A-1) and 10 parts by mass of granules containing copolymer (B-1), 10 parts by mass of styrene-based elastomer (E) (Asahi Kasei Corporation, Tuftec M1943: maleic anhydride modified SEBS, maleic anhydride addition rate 1.8% by mass, styrene content 20% by mass, MFR = 6.5 g / 10 min (230°C, 2.16 kgf)) was used. The resin composition (X) was prepared in the same manner as in Example 1, and a release film was made from this composition. The film-forming properties, physical properties of the release film, and compression molding were evaluated. The results are shown in Table 2.

[0300] <Example 8>

[0301] In Example 6, polybutylene terephthalate (A-2) was used as a component of the resin composition (X). Otherwise, the resin composition (X) was prepared in the same manner as in Example 1. A release film was then made from this composition, and the film-forming properties, physical properties of the release film, and compression molding were evaluated. The results are shown in Table 2.

[0302] <Comparative Example 1>

[0303] As a component of resin composition (X), only 100 parts by weight of polybutylene terephthalate (A-1) were used. Otherwise, resin composition (X) was prepared in the same manner as in Example 1. A release film was then made from this composition, and its film-forming properties, release film properties, and compression molding performance were evaluated. The results are shown in Table 2.

[0304] It should be noted that no peak was observed in the waveform of the loss tangent tanδ of the solid viscoelasticity at 20–35 °C measured by the above method. Therefore, the maximum value of the loss tangent tanδ in the range of 20–35 °C is shown.

[0305] <Comparative Example 2>

[0306] As components of the resin composition (X), 80 parts by weight of polybutylene terephthalate (A-1) and 20 parts by weight of polypropylene-ethylene random copolymer (ExxonMobil Chemical Co., Ltd., product name: Vistamaxx 6102: MFR=3.0 g / 10 min (230 °C, 2.16 kgf), ethylene content 16% by weight) as the polyolefin elastomer (C) were used. Otherwise, the resin composition (X) was prepared in the same manner as in Example 1. A release film was then made from this composition, and its film-forming properties, release film properties, and compression molding performance were evaluated. The results are shown in Table 2.

[0307] It should be noted that no peak was observed in the waveform of the loss tangent tanδ of the solid viscoelasticity at 20–35 °C measured by the above method. Therefore, the maximum value of the loss tangent tanδ in the range of 20–35 °C is shown.

[0308] <Comparative Example 3>

[0309] Except for the use of 40 parts by weight of polybutylene terephthalate (A-1) and 60 parts by weight of granules containing copolymer (B-1), the resin composition (X) was prepared in the same manner as in Example 1. A release film was then made from this composition, and its film-forming properties, release film properties, and compression molding performance were evaluated. The results are shown in Table 2.

[0310] <Comparative Example 4>

[0311] Except for the use of 40 parts by weight of polybutylene terephthalate (A-1) and 60 parts by weight of granules containing copolymer (B-2), the resin composition (X) was prepared in the same manner as in Example 1. A release film was then made from this composition, and its film-forming properties, release film properties, and compression molding performance were evaluated. The results are shown in Table 2.

[0312] [Table 2]

[0313]

[0314] It can be seen that the release films of Examples 1-8 exhibit superior conformability and wrinkle resistance compared to Comparative Examples 1 and 2. On the other hand, although Comparative Example 1, composed solely of polybutylene terephthalate (A-1), exhibits excellent release properties, no peak-like behavior was observed in the loss tangent tanδ of the solid viscoelasticity within the range of 20-35°C measured under stretching mode, frequency 1.0 Hz, heating rate 3°C / min, and strain 0.1%. Therefore, it can be concluded that the conformability of the release film of Comparative Example 1 is insufficient, and wrinkles in the release film are directly transferred to the FPC, resulting in the inability to obtain a high-quality FPC. Furthermore, Comparative Example 2, which includes a polyolefin elastomer (C) instead of copolymer (B), does not fully satisfy the requirements for release properties, conformability, and wrinkle resistance.

[0315] It is known that copolymer (B-1) is an amorphous polymer, and copolymer (B-2) has a melting point of 130°C, thus its heat resistance is insufficient. Therefore, in Comparative Examples 3 and 4, where the proportion of copolymer (B) is higher than that of polybutylene terephthalate (A-1) or (A-2), the release films exhibit poor release properties and tend to adhere easily to the FPC. Furthermore, it is known that in Comparative Examples 3 and 4, where the proportion of copolymer (B) is higher than that of polybutylene terephthalate (A-1) or (A-2), the thermal shrinkage rate of the release film increases, making it prone to wrinkling.

[0316] Furthermore, it can be seen that the release film of Example 6 has a smaller surface roughness and improved surface smoothness compared to Comparative Examples 2-4. It can also be seen that the release film of Example 7 has a larger film width during film forming and superior suppression of shrinkage during film forming compared to Comparative Examples 1-4.

[0317] The release film formed from the resin composition of the present invention has excellent conformability to the fine height differences (undulations) of the FPC, thus suppressing adhesive outflow, inhibiting wrinkle formation, and providing excellent release properties. Therefore, it can be suitable as a release film for the manufacturing process of printed wiring substrates.

[0318] Furthermore, the high quality and high productivity achieved by effectively utilizing compression molding and other processes in FPC manufacturing make it highly valuable in various fields such as the electrical and electronic components industry, the machinery industry, and the automotive industry.

Claims

1. A resin composition (X) comprising: 50-95 parts by weight of polybutylene terephthalate (A), and 5-50 parts by weight of 4-methyl-1-pentene-α-olefin copolymer (B) that meets the following requirement (Ba), in, The total amount of the above-mentioned polybutylene terephthalate (A) and the above-mentioned 4-methyl-1-pentene-α-olefin copolymer (B) is 100 parts by mass; Component (Ba): Composed of 60-90 mol% of structural units (i) derived from 4-methyl-1-pentene and 10-40 mol% of structural units (ii) derived from α-olefins having 2-4 carbon atoms, wherein the total of structural units (i) and structural units (ii) is 100 mol.

2. The resin composition (X) according to claim 1, wherein, The content of at least one elastomer selected from the group consisting of polyester elastomer (D) and styrene elastomer (E) is 0 to 30 parts by weight relative to 100 parts by weight of the resin composition.

3. The resin composition (X) according to claim 1 or 2, wherein, The 4-methyl-1-pentene-α-olefin copolymer (B) further satisfies the following requirement (Bb); Requirement (Bb): The melting point Tm as determined by differential scanning calorimetry (DSC) is not observed, or the melting point Tm as determined by differential scanning calorimetry (DSC) is in the range of less than 160°C.

4. The resin composition (X) according to claim 1 or 2, wherein, The 4-methyl-1-pentene-α-olefin copolymer (B) further satisfies the following requirement (Be); Requirements (Be): The intrinsic viscosity η, measured at 135°C in decahydronaphthalene solvent, is in the range of 0.8 to 3.0 dl / g.

5. The resin composition (X) according to claim 1 or 2, wherein, The 4-methyl-1-pentene-α-olefin copolymer (B) further satisfies the following requirements (Bg); Requirements (Bg): The ratio of weight-average molecular weight Mw to number-average molecular weight Mn, as determined by gel permeation chromatography (GPC), i.e., the molecular weight distribution Mw / Mn, is in the range of 1.5 to 3.

0.

6. The resin composition (X) according to claim 1 or 2, wherein, The melt volumetric flow rate (MVR) of the polybutylene terephthalate (A), measured according to JIS K7210-1:2014 at a temperature of 250°C and a load of 2.16 kgf, was 0.5–60 cm⁻¹. 3 / 10-minute range.

7. The resin composition (X) according to claim 1 or 2, wherein, The melt volumetric flow rate (MVR) of the polybutylene terephthalate (A), measured according to JIS K7210-1:2014 at a temperature of 250°C and a load of 2.16 kgf, was 15–50 cm⁻¹. 3 / 10-minute range.

8. The resin composition (X) according to claim 1 or 2, wherein, The melt volumetric flow rate (MVR) of the polybutylene terephthalate (A) was measured at 250°C and 2.16 kgf according to JIS K7210-1:2014, and was between 25 and 40 cm⁻¹. 3 / 10-minute range.

9. The resin composition (X) according to claim 1 or 2, wherein, The content of at least one elastomer selected from the group consisting of polyester elastomer (D) and styrene elastomer (E) is 5 to 15 parts by weight relative to 100 parts by weight of the resin composition.

10. A molded article comprising the resin composition (X) of claim 1 or 2.

11. A membrane comprising the resin composition (X) of claim 1 or 2.

12. The membrane according to claim 11, wherein it is a single-layer membrane.

13. The membrane according to claim 11, wherein, The critical surface tension at 23℃ is 20~30mN / m.

14. The membrane according to claim 11, wherein, For the membrane, the storage modulus E' of the solid viscoelasticity at 180°C, measured under the conditions of stretching mode, frequency 1.0 Hz, heating rate 3°C / min, and strain 0.1%, is in the range of 10~90 MPa.

15. The membrane according to claim 11, wherein, The maximum value of the loss tangent tanδ of solid viscoelasticity at 20~35℃ was determined under the conditions of tensile mode, frequency 1.0Hz, heating rate 3℃ / min, and strain 0.1%, i.e., the tanδ peak value ranged from 0.02 to 0.

30.

16. The membrane according to claim 11, wherein it is a release membrane.

17. The film according to claim 11 is a release film for a printed wiring substrate manufacturing process.

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