Stretchable thermoplastic resin composition, stretchable resin layer, laminate and semiconductor device

Abstract

A thermoplastic resin composition can be provided which has excellent stretchability and a low tack value, and which allows wiring to be formed by screen printing. By using such a composition, an excellent laminate and a semiconductor device can be provided. The recovery rate after tensile deformation to 100% strain is 88% or more, and the tack value is 10.5 gf / mm 2 A stretchable thermoplastic resin composition, which is:

Description

[Technical Field]

[0001] The present invention relates to an elastic thermoplastic resin composition having a specific recovery rate and tack value, an elastic resin layer, a laminate, and a semiconductor device. [Background technology]

[0002] Patent Document 1 describes a thermosetting composition for forming an elastic resin layer, which contains (A) a styrene-based elastomer partially modified with maleic anhydride, (B) a block polycarboxylic acid, and (C) a thermosetting resin. Patent Document 2 describes a conductive substrate having an elastic resin layer and a conductive foil provided on the elastic resin layer, wherein the elastic resin layer contains a cured product of a resin composition containing (A) a rubber component, (B) a crosslinking component, and (C) a silicone oil having a reactive terminal group, and the (B) crosslinking component contains at least one selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, and cresol novolac type epoxy resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-26744 A [Patent Document 2] Patent No. 7110711 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, technologies such as freely stretchable displays and sensors have been realized in the fields of wearable devices and healthcare-related equipment. Various sensors capable of detecting strain, minute pressure changes, and temperature have been used for industrial and medical applications. As they become smaller and lighter, they can now be attached to various everyday objects, including mobile devices, improving convenience and helping to avoid danger. In the future, as these sensors become lighter and more flexible and stretchable, they will be able to be attached to the body without any strain, potentially changing the way we live. In the field of sensors, various resin substrates and printed wiring boards using them have been used to reduce weight and size. However, due to their durability and compatibility with post-processing, most resin substrates have rigid chemical bonds and strong crystallinity. Printed wiring boards using these substrates can bend freely, but are difficult to stretch. Therefore, to create wearable devices that can bend and stretch freely, substrates or printed wiring boards with high stretchability are required. To impart high stretchability to printed wiring boards, the use of rubber and elastomer components as materials for the base substrate of printed wiring boards and the substrate that seals the wiring has been investigated. Furthermore, when using such elastic substrates for wiring, it is preferable to use substrates with low moisture permeability to prevent corrosion of the wiring. Examples of low-moisture permeable rubbers and elastomers include styrene-based elastomers and silicone rubber. Because silicone rubber repels ink and has processability issues, styrene-based elastomers are preferred. In the case of styrene-based elastomers, the elastomer component with good elasticity tends to cause strong surface tack, resulting in poor handleability. As a specific example, when drawing wiring on an elastic substrate by screen printing, if the substrate surface has strong tack, the printing plate will not peel easily, which will likely cause problems in forming wiring on a printed wiring board. Furthermore, when a printed wiring board is made from a material with strong tack, problems will likely arise in terms of adhesion of foreign matter and handleability of the board.

[0005] The present invention aims to provide a thermoplastic resin composition that has excellent stretchability and a low tack value, and that allows wiring to be formed by screen printing, and to provide an excellent laminate and semiconductor device by using such a composition. [Means for solving the problem]

[0006] The invention of claim 1, which was completed with this purpose in mind, has a recovery rate of 88% or more after tensile deformation to 100% strain, and a tack value of 10.5 gf / mm 2 The stretchable thermoplastic resin composition is as follows: The invention described in claim 2 is characterized in that, in the infrared absorption spectrum, the wave number is 695 cm ―1 ±10cm ―1 and 2920 cm ―1 ±10cm ―1 The stretchable thermoplastic resin composition according to claim 1 exhibits an absorption peak at The invention described in claim 3 is the 695 cm ―1 ±10cm ―1 The peak intensity at 2920 cm is defined as A. ―1 ±10cm ―1 3. The stretchable thermoplastic resin composition according to claim 2, wherein A / (A+B) is 0.40 to 0.70, where B is the peak intensity of the stretchable thermoplastic resin composition. A fourth aspect of the present invention is the stretchable thermoplastic resin composition according to the first aspect, wherein the stretchable thermoplastic resin composition contains a thermoplastic styrene-based elastomer. In the invention described in claim 5, the thermoplastic styrene-based elastomer contains two or more copolymers, and at least one of the copolymers has a wave number of 695 cm in an infrared absorption spectrum. ―1 ±10cm ―1 and 2920 cm ―1 ±10cm ―1 The absorption peak is at 695 cm ―1 ±10cm ―1 The peak intensity at 2920 cm is defined as a. ―1 ±10cm ―15. The stretchable thermoplastic resin composition according to claim 4, wherein when the peak intensity of the stretched thermoplastic resin composition is represented by b, a / (a+b) is 0.71 or more. A sixth aspect of the present invention is the stretchable thermoplastic resin composition according to the first aspect, wherein the stretchable thermoplastic resin composition does not contain a silicone compound. A seventh aspect of the present invention is the stretchable thermoplastic resin composition according to the first aspect, wherein the stretchable thermoplastic resin composition does not contain a curable compound. An eighth aspect of the present invention is a stretchable resin layer made of the stretchable thermoplastic resin composition according to any one of the first to seventh aspects. A ninth aspect of the present invention is a laminate obtained by laminating a substrate on at least one surface of the elastic resin layer according to the eighth aspect. A tenth aspect of the present invention is the laminate according to the ninth aspect, wherein the elastic resin layer has wiring formed by screen printing or metal. An eleventh aspect of the present invention is the laminate according to the tenth aspect, wherein another elastic resin layer is laminated on the wiring as a sealing layer for the wiring. A twelfth aspect of the present invention is a semiconductor device including the laminated body according to the eleventh aspect. [Effects of the Invention]

[0007] According to the present invention, by using a specific thermoplastic elastic resin composition, it is possible to provide a resin composition that has excellent elasticity while having a low tack value, and that allows wiring to be created by screen printing, and by using such a composition, it is possible to provide an excellent laminate and a semiconductor device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a stress-strain curve illustrating an example of measurement of recovery rate. [Figure 2] FIG. 1 is a cross-sectional view schematically illustrating a plate peeling test for a printing plate. [Figure 3] 1 is a cross-sectional view showing an outline of a method for producing an example of a laminate using an elastic resin layer in the present embodiment. [Figure 4]10A to 10C are cross-sectional views showing an outline of a method for producing another example of a laminate using an elastic resin layer in the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes in detail the preferred embodiments of the present invention. The following embodiments are merely examples, and the technical scope of the present invention is not limited to the following aspects. In this disclosure, the expressions "xx or more and xx or less" or "xx to xx" that represent a numerical range mean a numerical range that includes the stated upper and lower limits, unless otherwise specified.

[0010] <Stretchable thermoplastic resin composition> The stretchable thermoplastic resin composition according to this embodiment is thermoplastic and has a recovery rate of 88% or more after being tensile-deformed to a strain of 100%, and a tack value of 10.5 gf / mm 2 The following is the result. In this embodiment, the recovery rate of the stretchable thermoplastic resin composition can be determined by a tensile test using a test piece made of the resin composition. Specifically, as described in the Examples, a test piece, for example, 250 mm long and 10 mm wide, is prepared, and the first tensile test is performed until the longitudinal strain reaches 100%, in other words, until the length of the test piece doubles. The strain (displacement) when the test piece is tensile-deformed is defined as X. Next, the test piece is returned to its initial state, and the tensile deformation is performed again. The distance from the start of load application until the same 100% strain is reached is defined as Y, and the recovery rate is defined as R (%) calculated by the following formula: R(%)=(Y / X)×100

[0011] The thickness of the test piece is not particularly limited, but is usually the thickness of the elastic resin layer formed from the elastic thermoplastic resin composition. When comparing the recovery rates of multiple elastic thermoplastic resin compositions, it is also possible to prepare a test piece with a thickness of 40 μm as in the examples. Figure 1 shows a stress-strain curve that shows an example of measuring the recovery rate. In Figure 1, N1 is the stress-strain curve obtained from the first tensile test, and N2 is the stress-strain curve obtained from the second tensile test. The recovery rate can be calculated using the above formula from the amount of tensile deformation X in the first test in Figure 1 and the amount of tensile deformation Y from the start of the second load application, when stress is generated, until the strain reaches 100%. The higher the recovery rate, the higher the durability against repeated use and the higher the stretchability. In this embodiment, the recovery rate is 88% or more. The recovery rate is preferably 90% or more, and more preferably 91% or more. The recovery rate can be further increased to 95% or more, but if it is too high, the tack value may become high, so the recovery rate is determined taking into consideration the balance with other properties. The upper limit of the recovery rate by definition is 100%.

[0012] In this embodiment, the tack value of the stretchable thermoplastic resin composition is 10.5 gf / mm 2 The following is the result. Tack refers to the sticky feeling that occurs on the surface of a material such as rubber, and tackiness refers to the ability to adhere to an adherend with a light force. In this embodiment, as shown in the examples, the tack value of the surface of a resin layer made from a stretchable thermoplastic resin composition is measured. The measurement conditions are a pressing speed of 1 mm / sec, a lifting speed of 10 mm / sec, a load of 400 gf, a load holding time of 5 seconds, and a temperature of 25°C. For example, a tack tester (manufactured by Rhesca Corporation, product name "TAC1000") can be used as the measurement device, and this tester was set to constant load mode for measurement. The lower the tack value, the lower the adhesiveness of the resin layer, and the better the peelability of the printing plate used for printing printed wiring. Therefore, a lower tack value is preferable. The measured tack value is 10.5 gf / mm as described above. 2 less than 10.0gf / mm 2 Less than 9gf / mm is preferable 2 Less than 8gf / mm is more preferable, and even more preferable 2 The tack value is preferably 0 gf / mm or less. There is no lower limit for the tack value. 2 may be used, but typically 0.15gf / mm 2 That's all. The peelability of the printing plate from the resin layer can be confirmed as follows. FIG. 2 is a cross-sectional view that schematically illustrates a printing plate peeling test. A test piece of a resin layer 1 formed from a stretchable thermoplastic resin composition is attached to a substrate 2. Meanwhile, a mesh 21 to be used in the printing plate is prepared. Because the mesh 21 alone will bend, a mock plate is fabricated by fixing the ends of the mesh 21 to a reinforcing plate 22 with tape (not shown). The mesh 21 side of the mock plate is gently placed on top of the resin layer 1, and then the mock plate is lifted vertically to confirm whether the resin layer 1 and other components are lifted up together.

[0013] In order to achieve both the recovery rate and the tack value, the elastic thermoplastic resin composition has a wave number of 695 cm when measuring the infrared absorption spectrum of the composition. ―1 ±10cm ―1 and 2920 cm ―1 ±10cm ―1 It shows absorption peaks in both ranges of 695cm ―1 ±10cm ―1 The peak intensity of the peak at 2920 cm is A. ―1 ±10cm ―1 When the peak intensity of the peak at is B, A / (A+B)=0.40~0.70 It is preferable to satisfy the following relationship. If the ratio A / (A+B) is 0.40 or more, the tack value tends to be low, and if it is 0.70 or less, the recovery rate tends to be high and the stretchability of the resin composition tends to be good. This ratio is particularly preferably 0.43 to 0.65, even more preferably 0.45 to 0.60, and optimally 0.50 to 0.58. The reason for the presence of absorption peaks at these wavenumbers and the preferable relationship between the peak intensities is unclear. ―1 The absorption peak derived from the benzene ring is around 2920 cm ―1 This is the region where the absorption peaks due to -CH2 groups appear. Therefore, it is believed that the presence of benzene rings and -CH2 groups, and the presence of benzene rings and -CH2 groups in a specific ratio, produces a favorable effect. The infrared absorption spectrum is measured using a Fourier transform infrared spectrophotometer by the attenuated total reflection method. ―1 ±10cm ―1 and 2920cm ―1 ±10cm ―1 The strongest absorption peaks in each range are designated as A and B.

[0014] The resin composition constituting the stretchable thermoplastic resin composition according to this embodiment is not particularly limited as long as it has the above-mentioned recovery rate and tack value. The resin is preferably composed mainly of a thermoplastic elastomer, and particularly preferably of a composition containing a styrene-based thermoplastic elastomer. Examples of thermoplastic elastomers that can be used include styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, vinyl chloride-based elastomers, ethylene-vinyl acetate copolymers, ethylene propylene rubber, polyamide-based elastomers, chlorinated polyethylene, and polybutadiene-based elastomers. The weight average molecular weight of the thermoplastic elastomer is not particularly limited, but is usually preferably 20,000 to 150,000.

[0015] A particularly suitable elastomer for this embodiment is a styrene-based elastomer. A styrene-based elastomer is a thermoplastic elastomer containing styrene as a monomer component. Examples of preferred styrene-based elastomers include styrene-ethylene-propylene-styrene copolymer (SEPS), styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-butadiene-styrene copolymer (SBS), styrene-ethylene-propylene copolymer (SEP), and styrene-ethylene-ethylene-propylene-styrene copolymer (SEEPS). In order to obtain the stretchable thermoplastic resin composition according to this embodiment, it is preferable to use multiple types of styrene-based elastomers as materials and mix them to give the resin composition the desired recovery rate, tack value, etc. "Multiple types" refers not only to the case where the type of copolymer used as the elastomer is a mixture of copolymers composed of different monomers, such as a styrene-ethylene-propylene copolymer (SEP) and a styrene-ethylene-propylene-styrene copolymer (SEPS), but also to the case where the monomer composition, molecular weight, etc. are different even within a styrene-ethylene-propylene-styrene copolymer (SEPS).

[0016] At least one of the multiple types of styrene-based elastomers used as a material for obtaining the stretchable thermoplastic resin composition has a wave number of 695 cm in the infrared absorption spectrum of the elastomer. ―1 ±10cm ―1 The intensity of the strongest peak in the range is a, and the wavenumber is 2920 cm ―1 ±10cm ―1 When the intensity of the strongest peak within the range is defined as b, the ratio of a / (a+b) is preferably 0.71 or more. Furthermore, to obtain a resin composition, it is preferable to use a styrene-based elastomer having an a / (a+b) ratio of 0.70 or less. In particular, it is preferable to use three types of styrene-based elastomers as materials having an a / (a+b) ratio of 0.43 or less, 0.44 to 0.70, and 0.71 to 0.97. Specific examples of styrene-based elastomers that can be used with these three a / (a+b) ratios include the following products: Styrene elastomers with a / (a+b) ratio of 0.43 or less SEBS copolymer: "Tuftec (registered trademark) H1221, H1062, H1521, H1052, M1943, P1083" (manufactured by Asahi Kasei Corporation), "Kraton (registered trademark) FG1924 GT, G1657 MS" (Kraton Polymer Japan Co., Ltd.) SEPS copolymer: "Septon (registered trademark) 2004F, 2005, 2063" (manufactured by Kuraray Co., Ltd.), "Kraton (registered trademark) G1730 VO" (Kraton Polymer Japan Co., Ltd.) SEEPS copolymer: "Septon (registered trademark) 4030S" (Kuraray Co., Ltd.) SBS copolymer: "Kraton (registered trademark) D1116 AT, DX405 JOP, DX410 JS" (Kraton Polymer Japan Co., Ltd.) Styrene elastomers with a / (a+b) ratio of 0.44 to 0.70 SEBS copolymer: "Tuftec (registered trademark) H1053, H1041, H1272, N504, M1911, M1913, MP10, P1500" (manufactured by Asahi Kasei Corporation), "Septon (registered trademark) 8004, 8006, 8007L" (manufactured by Kuraray Co., Ltd.), "Kraton (registered trademark) G1702 HU, G1650 EU, G1633 EU, FG1901 GT, G1653 VO, G1654 HU, G1726 MS, G4609 HI, G4610 HU, G1652 EU, G1660 HU, G1651 EU, E1830 HU" (manufactured by Kraton Polymer Japan Co., Ltd.) SEP copolymer: "Septon (registered trademark) 1020" (manufactured by Kuraray Co., Ltd.), "Kraton (registered trademark) G1701 MU" (Kraton Polymer Japan Co., Ltd.) SEPS copolymer: "Septon (registered trademark) 2002, 2006" (Kuraray Co., Ltd.) SEEPS copolymer: "Septon (registered trademark) 4033, 4044, 4055, 4077, 4099" (manufactured by Kuraray Co., Ltd.) SBS copolymer: "Kraton (registered trademark) D1152 ET, D1157 ES, D1102 JSZ, D1184 AT, D1192 AT, D0243 ET, D1101 JU, D4150 KT, D1118 ET, D1191 ET, D4153 ES" (manufactured by Kraton Polymer Japan Co., Ltd.) Styrene elastomer with a / (a+b) ratio of 0.71 or more SEBS copolymer: "Tuftec (registered trademark) H1051, H1517, H1043, P5051, P2000" (manufactured by Asahi Kasei Corporation), "Kraton (registered trademark) A1535 HU, A1537 HU" (Kraton Polymer Japan Co., Ltd.) SEPS copolymer: "Septon (registered trademark) 2104" (manufactured by Kuraray Co., Ltd.), "Kraton (registered trademark) D1155 JOP, A1536 HU" (Kraton Polymer Japan Co., Ltd.) SBS copolymer: "Kraton (registered trademark) DX408 JOP" (Kraton Polymer Japan Co., Ltd.) The content ratio of these three types of styrene elastomers is not particularly limited, but the following amounts can be shown as preferred examples. The content of styrene elastomers with a / (a+b) ratio of 0.43 or less is 5% by mass or more and 50% by mass or less, particularly 10% by mass or more and 45% by mass or less The styrene elastomer with a ratio of a / (a+b) of 0.44 to 0.70 is 35% by mass to 85% by mass, particularly 40% by mass to 80% by mass. The content of styrene elastomers with a / (a+b) ratio of 0.71 to 0.97 is 1% by mass to 35% by mass, particularly 2% by mass to 30% by mass. In this embodiment, by using multiple types, preferably three or more types, of styrene-based elastomers having different a / (a+b) ratios, it becomes easier to obtain an elastic thermoplastic resin composition with a good balance between recovery rate and tack value. The infrared absorption spectrum of the styrene-based elastomer is measured by the attenuated total reflection method using a Fourier transform infrared spectrophotometer, in the same manner as the infrared absorption spectrum of the entire resin composition. ―1 ±10cm ―1 and 2920cm ―1 ±10cm ―1 The strongest peak intensities among the absorption peaks in each range are designated as a and b. The proportion of the styrene elastomer in the stretchable thermoplastic resin composition is usually 90% by mass or more, particularly 95% by mass or more, and even more preferably 98% by mass or more, and the composition may be substantially entirely made of a styrene elastomer. However, the thermoplastic elastomer may contain components other than the styrene elastomer to the extent that the desired physical properties and manufacturability are not impaired. Examples of usable thermoplastic elastomers include the elastomers described above.

[0017] In addition, the stretchable thermoplastic resin composition of the present embodiment preferably has the following physical property values. The resin layer formed from the stretchable thermoplastic resin composition preferably has a tensile stress of 0.1 MPa or more and 20 MPa or less at 10% to 100% elongation. When the tensile stress is within this range, the resin layer tends to have particularly excellent handleability and flexibility. The tensile stress at 10% to 100% elongation is particularly preferably 0.5 MPa or more and 10 MPa or less, and more preferably 1.0 MPa or more and 4.0 MPa or less. The tensile stress of the resin layer at 10% elongation is preferably in the range of 1.0 MPa or more and 2.1 MPa or less, and particularly preferably 1.3 MPa or more and 1.9 MPa or less. The preferred range of tensile stress at 30% elongation is 1.5 MPa or more and 2.6 MPa or less, and particularly preferably 1.8 MPa or more and 2.3 MPa or less. The preferred range of tensile stress at 50% elongation is 1.6 MPa or more and 2.7 MPa or less, and particularly preferably 1.9 MPa or more and 2.4 MPa or less. The preferred range of tensile stress at 100% elongation is 1.8 MPa or more and 3.0 MPa or less, and particularly preferably 2.1 MPa or more and 2.7 MPa or less.

[0018] The breaking elongation of the resin layer obtained from the stretchable thermoplastic resin composition in this embodiment is preferably 200% or more. When the breaking elongation is 200% or more, sufficient stretchability tends to be easily obtained at 100% elongation. From this viewpoint, the breaking elongation is preferably as large as possible, more preferably 300% or more, even more preferably 400% or more, even more preferably 500% or more, and particularly preferably 600% or more. There is no particular upper limit to the breaking elongation, but in most stretchable thermoplastic resin compositions, it is usually 1000% or less.

[0019] The stretchable thermoplastic resin composition of the present embodiment may be composed of only the elastomer component, or may contain additives such as fillers, flame retardants, and antioxidants to the extent that the desired physical properties are not impaired. In addition, since the stretchable thermoplastic resin composition is likely to repel ink, it is preferable that it does not substantially contain a silicone compound. By not using a silicone compound, wiring can be produced by screen printing. Furthermore, in order to maintain thermoplasticity, it is preferable that the stretchable thermoplastic resin composition does not substantially contain a curable compound such as an epoxy resin. <Filler> Examples of fillers include particles made of inorganic compounds such as titanium oxide, aluminum oxide, zinc oxide, carbon black, calcium carbonate, silica, talc, copper, silver, etc., and particles made of organic compounds such as fluoropolymers (polytetrafluoroethylene, perfluoroalkoxyalkane, etc.) and various elastomers. These may be used alone or in combination of two or more.

[0020] <Flame retardant> The flame retardant may be either an organic flame retardant or an inorganic flame retardant. Examples of organic flame retardants include phosphorus-based flame retardants such as melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium amido phosphate, ammonium amido polyphosphate, carbamate phosphate, carbamate polyphosphate, aluminum trisdiethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, titanium tetrakisdiethylphosphinate, titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titanyl bisdiphenylphosphinate, and titanium tetrakisdiphenylphosphinate; nitrogen-based flame retardants such as triazine-based compounds such as melamine, melam, and melamine cyanurate, cyanuric acid compounds, isocyanuric acid compounds, triazole-based compounds, tetrazole compounds, diazo compounds, and urea; and silicon-based flame retardants such as silicone compounds and silane compounds. Examples of inorganic flame retardants include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, and calcium hydroxide; metal oxides such as tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, and nickel oxide; zinc carbonate, magnesium carbonate, barium carbonate, zinc borate, and hydrated glass. Two or more of these flame retardants can be used in combination.

[0021] <Antioxidants> The antioxidant is not particularly limited, and examples thereof include 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenol, triethylene glycol-bis(methylphenyl)propionate]methane, methylphenyl ether ... Examples of antioxidants include phenol-based antioxidants such as tris[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate; sulfur-based antioxidants such as dilauryl-3,3'-thiodipropionate and dimyristyl-3,3'-dithiopropionate; and phosphorus-based antioxidants such as trisnonylphenyl phosphite and tris(2,4-di-tert-butylphenyl)phosphite. These may be used alone or in combination of two or more.

[0022] The method for producing the stretchable thermoplastic resin composition according to the present embodiment is not particularly limited, but it can be produced, for example, by a method including dissolving or dispersing a resin in an organic solvent to obtain a resin varnish, and forming the resin varnish into a film on a substrate by the method described below. From the viewpoint of workability during resin film formation, the solid content concentration of the resin, etc. in the solvent is preferably 10% by mass or more and 50% by mass or less, and particularly preferably 15% by mass or more and 40% by mass or less. If the solid content concentration is too high, the viscosity of the solvent increases, which tends to make uniform coating difficult.

[0023] <Organic solvents> The organic solvent to be used is not particularly limited as long as it can uniformly dissolve or disperse various resins. Specific examples thereof include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane, heptane, octane, and decane; alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane, and ethylcyclohexane; halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, and chloroform; alcoholic solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol; acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, and the like. Examples of suitable solvents include ketone solvents such as isophorone and acetophenone; cellosolves such as methyl cellosolve and ethyl cellosolve; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and butyl formate; and glycol ether solvents such as ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso-butyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether. These may be used alone or in combination of two or more. Generally, organic solvents are preferred over inorganic solvents from the viewpoint of workability. Low-polarity solvents such as aromatic hydrocarbons and aliphatic hydrocarbons are particularly preferred from the viewpoint of solubility.

[0024] The thickness of the stretchable thermoplastic resin composition according to this embodiment after drying is not particularly limited. This thickness is mainly determined by the use of the resulting stretchable resin layer, and is usually 1 to 150 μm, preferably 5 to 100 μm. Within this range, the stretchable thermoplastic resin composition is likely to have sufficient strength, and drying can be carried out sufficiently, thereby reducing the amount of residual solvent in the resin film.

[0025] Next, a laminate using an elastic resin layer made of the elastic thermoplastic resin composition according to this embodiment will be described with reference to FIG. FIG. 3 is a cross-sectional view showing an outline of a method for producing an example of a laminate using the elastic resin layer 1 in this embodiment. 3(a), a laminate is obtained by laminating a substrate 2 on at least one surface of an elastic resin layer 1. The substrate 2 used in the laminate is not particularly limited as long as it can be used to form an elastic resin layer 1 by applying and drying the elastic thermoplastic resin composition of the present invention, and examples thereof include a resin substrate, a release resin substrate, a paper substrate, and a release paper substrate.

[0026] <Resin substrate> By using a resin substrate, it is possible to achieve improvements in the electrical insulation and mechanical strength of the laminate. Examples of resin substrates include polyester resins, polyamide resins, polyimide resins, polyamideimide resins, liquid crystal polymers, polyphenylene sulfide, syndiotactic polystyrene, polyolefin-based resins, and fluorine-based resins. The resin is preferably in the form of a film.

[0027] <Release resin substrate> Among resins, a release resin substrate having releasability can be used. Examples of the release resin substrate include various olefin films alone, such as polyethylene, polypropylene, ethylene-α-olefin copolymer, and propylene-α-olefin copolymer, and films such as polyethylene terephthalate coated with a silicone-based, fluorine-based, or alkyd-based release agent.

[0028] <Paper base material> The use of a paper substrate can improve the electrical insulation and mechanical strength of the laminate. Examples of paper substrates include fine paper, kraft paper, roll paper, and glassine paper. Another example is a composite material obtained by impregnating a paper substrate with glass epoxy or the like.

[0029] <Release paper base material> Among paper substrates, a release paper substrate having releasability can be used. Examples of the release paper substrate include the above-mentioned paper substrate having a coating layer of a filler such as clay, polyethylene, or polypropylene on one or both sides thereof, and a silicone-based, fluorine-based, or alkyd-based release agent further coated on each coating layer.

[0030] Next, as shown in FIG. 3(b), wiring 3 made of conductive ink is formed on the elastic resin layer 1 laminated on the substrate 2 by screen printing. Next, as shown in FIG. 3(c), another stretchable resin layer 1' is pressed onto the wiring 3 to seal it. The stretchable thermoplastic resin composition used for this stretchable resin layer 1' is usually the same as the resin composition used for the stretchable resin layer 1, and it is preferable to completely integrate the stretchable resin layers 1 and 1', but a different stretchable thermoplastic resin composition can also be used. Even when a different stretchable thermoplastic resin composition is used, it is preferable that the recovery rate and tack value are within the same range as the composition of this embodiment. If necessary, as shown in FIG. 3(c), a protective substrate 2' may be attached to the elastic resin layers 1, 1' to protect the elastic resin layers 1, 1', forming a three-layer laminate consisting of the substrate 2, the elastic resin layers 1, 1', and the protective substrate 2'. The presence of the protective substrate 2' allows winding without causing offset onto the substrate 2, improving operability, and also protects the elastic resin layers 1, 1', improving the shelf life of the entire laminate. The protective substrate 2' can be the same substrate as the substrate 2, but it is particularly preferable to use the release resin substrate or release paper substrate described above.

[0031] Next, another example of a laminate using an elastic resin layer made of the elastic thermoplastic resin composition according to this embodiment will be described with reference to FIG. Fig. 4 is a cross-sectional view showing an outline of a manufacturing method of another example of a laminate using the elastic resin layer 1 in this embodiment. In Fig. 3, the wiring 3 is formed from conductive ink by screen printing, but Fig. 4 shows an example in which the wiring 5' is formed from a metal layer 5. As shown in Figure 4(a), a substrate 2 is laminated on one surface of the elastic resin layer 1. This substrate 2 can be the same as that used in Figure 3, and examples include a resin substrate, a release resin substrate, a paper substrate, and a release paper substrate. In addition, a metal layer 5 is formed on the surface of the elastic resin layer 1 opposite the substrate 2.

[0032] <Metal layer> The substrate of the metal layer 5 can be any conventionally known conductive material that can be used for circuit boards. Examples of the substrate include various metals such as SUS, copper, aluminum, iron, steel, zinc, and nickel, as well as alloys, plated products, and metals treated with other metals such as zinc or chromium compounds. A metal foil is preferred, and a copper foil is more preferred. The thickness of the metal foil is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 10 μm or more. It is also preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the wiring, while if the thickness is too thick, the processing efficiency during wiring production may decrease. Metal foils are usually provided in a roll form. The form of the metal foil used when manufacturing the printed wiring board of the present invention is not particularly limited. When a ribbon-shaped metal foil is used, its length is not particularly limited. Its width is also not particularly limited, but is preferably about 250 to 1000 mm. Methods for forming the metal layer 5 include applying an elastic resin layer directly to a metal foil, pressing it onto a metal foil, forming it by plating, vacuum deposition, spraying, etc., but the method of pressing it onto a metal foil is common. Next, as shown in FIG. 4(b), unnecessary portions of the metal layer 5 are removed by etching or the like to form metal wiring 5'.

[0033] Next, as shown in Fig. 4(c), another elastic resin layer 1' is pressed onto the wiring 5' to seal it. If necessary, as shown in Fig. 4(c), a protective substrate 2' may be attached onto the elastic resin layers 1, 1' to protect the elastic resin layers 1, 1', forming a three-layer laminate consisting of the substrate 2, elastic resin layers 1, 1', and protective substrate 2'. The other elastic resin layer 1' and protective substrate 2' in Fig. 4(c) are the same as the other elastic resin layer 1' and protective substrate 2' in Fig. 3(c). 3 and 4, the stretchable thermoplastic resin composition of the present embodiment is preferably annealed after obtaining the resin composition or after forming the stretchable resin layer 1. The annealing is carried out to remove residual stress. <Printed wiring board> The laminate according to this embodiment can be manufactured by the manufacturing method shown in Figs. 3 and 4, etc. The manufactured laminate can be used as a printed wiring board. A printed wiring board includes, as a component, a laminate formed from wiring and an elastic resin layer. Printed wiring boards include so-called flexible circuit boards (FPCs), flat cables, circuit boards for tape automated bonding (TAB), etc., in which a conductor circuit formed from metal is partially or entirely covered with a cover film, screen printing ink, etc., as necessary. The printed wiring board according to this embodiment may have any laminated structure that can be used as a printed wiring board, for example, a printed wiring board composed of three layers: an elastic substrate layer, a metal layer, and a sealing material layer. Furthermore, if necessary, two or more of the above printed wiring boards may be stacked.

[0034] <Semiconductor device> The semiconductor device according to this embodiment can be manufactured using a printed wiring board using the laminate according to this embodiment. The semiconductor device according to this embodiment can be manufactured by mounting circuit components on conductive locations on the printed wiring board. The conductive locations may be either on the surface or embedded in the printed wiring board, as long as they transmit electrical signals. Furthermore, the circuit components are typically primarily composed of semiconductor chips, but the semiconductor chips are not particularly limited as long as they are electrical circuit elements made of semiconductor material. The mounting method of circuit components for manufacturing a semiconductor device is not particularly limited as long as the semiconductor chip functions effectively, but specific examples include wire bonding mounting, flip chip mounting, bumpless buildup layer (BBUL) mounting, anisotropic conductive film (ACF) mounting, non-conductive film (NCF) mounting, etc. Note that the "bumpless buildup layer (BBUL) mounting method" refers to a mounting method in which a semiconductor chip is directly embedded in a recess in a printed wiring board and the semiconductor chip is connected to the wiring on the printed wiring board.

[0035] The present invention is not limited to the above-described embodiment, and other embodiments are possible within the scope of the present invention. [Example]

[0036] Hereinafter, the embodiments of the present invention will be described in detail with reference to examples, but the embodiments of the present invention are not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are by mass.

[0037] Example 1 <Preparation of Resin Varnish for Forming Stretchable Resin Composition> The following styrene elastomers E1, E2, and E3 were dissolved in toluene to prepare solutions with a concentration of 25%. The three elastomer solutions obtained were thoroughly stirred with a spatula and then mixed to obtain a resin varnish. Styrene-based elastomer (SEBS copolymer) E1 60.0 parts Styrene-based elastomer (SEBS copolymer) E2 35.0 parts Styrene-based elastomer (SEPS copolymer) E3 5.0 parts The physical properties of each styrene elastomer are listed in Table 1. The explanation for a / (a+b) in Table 1 is as follows: a / (a+b): In the infrared absorption spectrum, the wave number is 695 cm ―1 ±10cm ―1 The intensity of the strongest peak in the range is a, and the wavenumber is 2920 cm ―1 ±10cm ―1 The intensity of the strongest peak within the range was determined as b. The infrared absorption spectrum was measured using a Fourier transform infrared spectrophotometer, product name "Spectrum 3" manufactured by PerkinElmer Japan Co., Ltd., using the attenuated total reflection method at a wave number of 650 cm ―1 ~4000cm ―1 The range was determined by measuring four times.

[0038] [Table 1]

[0039] <Preparation of laminate> A 50 μm-thick polyethylene terephthalate film (Higashiyama Film Co., Ltd., product name "HY-NS70") with one surface treated for release was prepared as a coating substrate. The resin varnish described above was applied to the release-treated surface of this polyethylene terephthalate film using a Baker-type applicator (Tester Sangyo Co., Ltd., product name "SA-201"). The coating was dried at 150°C for 2 minutes in a dryer (Futaba Scientific Co., Ltd., product name "MSO-06-05S") to obtain a 40 μm-thick elastic layer. A polyethylene terephthalate film (Higashiyama Film Co., Ltd., product name "HY-US20") with one surface treated for release was attached to the resulting elastic resin layer as a protective substrate, with the release-treated surface facing the elastic resin layer. The laminate was then laminated using a pressure laminator (manufactured by MCK Corporation, product name "MCL-500W") under conditions of a pressure of 0.3 MPa, 60°C, and a roll rotation speed of 1 m / min. Next, to remove residual stress in the elastic resin layer, the laminate was heated and annealed at 80°C for 24 hours in a thermostatic chamber (manufactured by Yamato Scientific Co., Ltd., product name "DKN612") to obtain a laminate.

[0040] (Examples 2 to 5, Comparative Example 1) A resin varnish and a laminate were prepared in the same manner as in Example 1, except that the ratios of the styrene elastomers E1, E2, E3, and E3' used in the resin varnish were changed to the ratios shown in Table 2. The a / (a+b) of E3' is shown in Table 1.

[0041] (Comparative Example 2) The following styrene elastomer E4, epoxy resin B1, and curing accelerator C were used in the amounts shown in Table 2, and each was dissolved in toluene to prepare a 25% solution. The three toluene solutions obtained were thoroughly stirred with a spatula and then mixed to obtain a resin varnish. A laminate was produced using the obtained resin varnish in the same manner as in Example 1. Styrene-based elastomer (SEBS copolymer) E4 Maleic anhydride modified hydrogenated styrene thermoplastic elastomer Manufactured by Asahi Kasei Corporation, product name "Tuftec (registered trademark) M1943" MFR[g / 10min](230℃, 2.16kg):8.0 Styrene content: 20% Epoxy Resin B1 Dicyclopentadiene epoxy resin Product name: EPICLON (registered trademark) HP7200HHH, manufactured by DIC Corporation Curing accelerator C 2-Ethyl-4-methylimidazole Product name: Curezol (registered trademark) 2E4MZ, manufactured by Shikoku Kasei Co., Ltd.

[0042] (Comparative Examples 3 and 4) A resin varnish and a laminate were prepared in the same manner as in Comparative Example 2, except that the epoxy resin was changed to the following epoxy resin B2 or B3, and the amounts of styrene-based elastomer E4 and epoxy resin used were changed to the amounts shown in Table 2. Epoxy Resin B2 Bisphenol A epoxy resin Mitsubishi Chemical Corporation, product name "jER (registered trademark) 828" Epoxy Resin B3 Cresol novolac epoxy resin Manufactured by DIC Corporation, product name "EPICLON (registered trademark) N-690"

[0043] [Measurement of recovery rate] The coated substrate and protective substrate were removed from the laminates obtained in the examples and comparative examples to prepare rectangular elastic resin layer test pieces measuring 250 mm in length, 10 mm in width, and 40 μm in thickness. These test pieces were stretched to 100% strain using a Strograph (manufactured by Toyo Seiki Seisaku-sho, Ltd., product name "VGS05-E") at a chuck distance of 50 mm and a tensile speed of 200 mm / min. The stress was then released and the test piece was returned to the initial position, after which a tensile test was performed again. Figure 1 shows a stress-strain curve illustrating an example of measuring the recovery rate. The recovery rate R was calculated using the following formula, where X is the strain (displacement) applied in the first tensile test, and Y is the difference between the position at which the load begins to be applied when the tensile test is performed again and X. In this test, X is the reference displacement in the first test, and when Y = X, the recovery rate R is 100%. The results are shown in Table 2. R(%)=(Y / X)×100

[0044] [Measurement of stress and elongation at break at 10% to 100% elongation] The coated substrate and protective substrate were removed from the laminates obtained in the Examples and Comparative Examples, and the elastic resin layer was cut into strips measuring 250 mm in length, 10 mm in width, and 40 μm in thickness to obtain test specimens. A tensile test was performed on the test specimens using a Strograph (manufactured by Toyo Seiki Seisaku-sho, Ltd., product name "VGS05-E") to obtain stress-strain curves. From the obtained stress-strain curves, the stress and elongation at break were determined at 10%, 30%, 50%, and 100% elongation. The tensile test was performed under conditions of a chuck distance of 50 mm and a tensile speed of 200 mm / min. The strain at the time the test specimen broke was recorded as the elongation at break. The results are shown in Table 2.

[0045] [Measurement of tack value] The protective substrate was removed from the laminate obtained in the examples and comparative examples, and the tack value of the surface of the elastic resin layer was measured using a tack tester (manufactured by Rhesca Co., Ltd., product name "TAC1000"). The measurement conditions were a pressing speed of 1 mm / sec, a lifting speed of 10 mm / sec, a load of 400 gf, a load holding time of 5 seconds, and a temperature of 25° C., and the measurement was set in constant load mode. The results are shown in Table 2.

[0046] [Printing plate peeling] To confirm that the surface tack value correlates with the plate peelability of the printing plate, plate peelability was evaluated using a mesh 21 used for printing plates, as shown in Figure 2. Mesh 21 was a calendered SUS mesh (manufactured by Mesh Co., Ltd., material: SUS304, thickness: 45 μm, wire diameter: 30 μm, mesh count: 250 mesh / inch, opening size: 72 μm, porosity: 50%). Since the SUS mesh alone sagged and did not provide consistent plate peelability results, a mock plate was created by taping the edges of a 180 mm square SUS mesh to a 200 mm square reinforcing plate 22 to prevent sagging. The mock plate weighed 45 g. After removing the protective substrate from a 100 mm square laminate, the mock plate was gently placed with the SUS mesh side facing up onto the elastic resin layer 1. After leaving it for 10 seconds, the mock plate was lifted vertically to confirm whether it would adhere to the laminate and lift up with it. The results are shown in Table 2. In Table 2, "1" indicates good plate peeling properties, meaning that the laminate did not lift up together with the SUS mesh, and "2" indicates poor plate peeling properties, meaning that the laminate lifted up together with the SUS mesh.

[0047] [Infrared absorption spectrum measurement] In order to calculate the value of A / (A+B) of the stretchable resin layer of the laminate obtained in the examples and comparative examples, infrared absorption spectrum measurement was carried out. The protective substrate was removed from the laminate obtained in each of the examples and comparative examples, and the infrared absorption spectrum of the elastic resin layer was determined. The measurement was performed using a Fourier transform infrared spectrophotometer, product name "Spectrum 3" manufactured by PerkinElmer Japan Co., Ltd., using the attenuated total reflection method at a wave number of 650 cm. ―1 ~4000cm ―1 The range was measured four times. Wave number: 695 cm ―1 ±10cm ―1 The intensity of the strongest peak within the range is A, and the wavenumber is 2920 cm ―1 ±10cm ―1 The intensity of the peak with the strongest intensity within this range was defined as B, and the value of A / (A+B) was calculated.

[0048] [Table 2] As is clear from the results shown in Table 2, the stretchable resin compositions of Examples 1 to 5 have high stretchability, reduced tackiness, and good peelability from the printing plate. [Industrial Applicability]

[0049] The laminate formed from the stretchable thermoplastic resin composition of the present invention has high stretchability while having reduced tackiness. Therefore, semiconductor devices using the laminate of the present invention can be used in various wearable devices, biosensors, etc., and the stretchable thermoplastic resin composition of the present invention can be used for sealing connector members, protecting protective films, and protecting wiring on flexible substrates, etc. Furthermore, examples of applications in which the semiconductor device can be used include electrical appliances such as computers, mobile phones, digital cameras and televisions, and vehicles such as motorcycles, automobiles, trains, ships and aircraft. [Explanation of symbols]

[0050] REFERENCE SIGNS LIST 1, 1'...elastic resin layer, 2...substrate, 2'...protective substrate, 3...wiring, 5...metal layer, 5'...wiring, 21...mesh, 22...reinforcing plate

Claims

1. The recovery rate after tensile deformation to 100% strain is 88% or more, and the tack value is 10.5 gf / mm ２ Below is the Stretchable thermoplastic resin composition.

2. In the infrared absorption spectrum, the wave number is 695 cm ―１ ±10cm ―１ and 2920 cm ―１ ±10cm ―１ The stretchable thermoplastic resin composition according to claim 1, which exhibits an absorption peak at

3. The above 695 cm ―１ ±10cm ―１ The peak intensity at 2920 cm is defined as A. ―１ ±10cm ―１ When the peak intensity is B, A / (A+B)=0.40~0.70 The stretchable thermoplastic resin composition according to claim 2, wherein

4. The stretchable thermoplastic resin composition according to claim 1 , wherein the stretchable thermoplastic resin composition comprises a thermoplastic styrene-based elastomer.

5. The thermoplastic styrene-based elastomer contains two or more copolymers, At least one of the copolymers has an infrared absorption spectrum with a wave number of 695 cm ―１ ±10cm ―１ and 2920 cm ―１ ±10cm ―１ The absorption peak is at 695 cm ―１ ±10cm ―１ The peak intensity at 2920 cm is defined as a. ―１ ±10cm ―１ 5. The stretchable thermoplastic resin composition according to claim 4, wherein a / (a+b) is 0.71 or more, where b is the peak intensity of the stretchable thermoplastic resin composition.

6. The stretchable thermoplastic resin composition according to claim 1 , wherein the stretchable thermoplastic resin composition does not contain a silicone compound.

7. The stretchable thermoplastic resin composition of claim 1 , wherein the stretchable thermoplastic resin composition does not contain a curable compound.

8. A stretchable resin layer comprising the stretchable thermoplastic resin composition according to any one of claims 1 to 7.

9. A laminate obtained by laminating a substrate on at least one surface of the stretchable resin layer according to claim 8.

10. The laminate according to claim 9 , wherein the elastic resin layer has wiring formed by screen printing or metal.

11. The laminate according to claim 10, wherein another elastic resin layer is laminated on the wiring as a sealing layer for the wiring.

12. A semiconductor device comprising the stack according to claim 11.

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