Laminate and method for producing epoxy resin sheet

Abstract

To provide an epoxy resin sheet which is excellent in stretchability even under low temperature environment and is excellent in impact resistance.SOLUTION: A laminate includes an epoxy resin sheet (A) and a carrier sheet (B) on at least one surface of the epoxy resin sheet (A), where there is at least one maximum value of a loss tangent (tanδ) obtained by dynamic viscoelasticity measurement in a tensile mode at a frequency of 1 Hz of the epoxy resin sheet (A) in a range of -100°C to 10°C, and tensile elongation of the epoxy resin sheet (A) is 50% or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate and a method for producing an epoxy resin sheet. [Background technology]

[0002] Epoxy resins are used in a variety of fields due to their excellent heat resistance, adhesive properties, water resistance, mechanical strength, and electrical properties. In particular, in the electrical and electronic fields, the miniaturization, precision, and high performance of electrical and electronic components have led to a demand for high moldability in the epoxy resins used. Recently, there has also been a demand for adaptability to applications that place greater emphasis on flexibility, such as flexible and stretchable laminates.

[0003] Patent Document 1 discloses a specific highly flexible epoxy resin, and states that a resin composition containing this epoxy resin gives a cured product that has a good balance of adhesiveness and electrical properties while also having high flexibility. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-320477 Summary of the Invention [Problem to be solved by the invention]

[0005] When a highly flexible epoxy resin cured material is thinned and molded into a single-layer sheet, the single-layer sheet has the advantage of being excellent in flexibility and stretchability. However, the single-layer sheet sometimes has insufficient stretchability, particularly in low-temperature environments.

[0006] Furthermore, since epoxy resin sheets are expected to find further applications, it is desired to develop epoxy resin sheets that have excellent impact resistance so that they can withstand various conditions.

[0007] Therefore, an object of the present invention is to provide a laminate including an epoxy resin sheet that has excellent elasticity even in a low-temperature environment and excellent impact resistance, and a method for producing the epoxy resin sheet. [Means for solving the problem]

[0008] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by using a laminate having a specific configuration, and have thus completed the present invention.

[0009] . That is, the present invention relates to the following [1] to

[18] . [1] A laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one side of the epoxy resin sheet (A), A laminate in which the epoxy resin sheet (A) has at least one maximum loss tangent (tanδ) in the range of -100°C to 10°C as obtained by dynamic viscoelastic measurement in a tensile mode at a frequency of 1 Hz, and the epoxy resin sheet (A) has a tensile elongation of 50% or more. [2] The laminate according to the above [1], wherein the maximum value of the loss tangent (tanδ) in the range of -100°C to 10°C obtained by dynamic viscoelasticity measurement of the epoxy resin sheet (A) in a tensile mode at a frequency of 1 Hz is 0.10 or more. [3] The laminate according to the above [1] or [2], wherein the loss tangent (tanδ) of the epoxy resin sheet (A) at -40°C to 40°C obtained by dynamic viscoelasticity measurement in a tensile mode at a frequency of 1 Hz is 0.03 or more. [4] The epoxy resin sheet (A) has a tensile storage modulus of 5.0 × 10 at −20 to 100° C. 5 ~1.0×10 9 The laminate according to any one of the above [1] to [3], wherein Pa. [5] The laminate has a tensile storage modulus of 6.0 × 10 at 20 to 100 ° C. 7 ~5.0×10 10 The laminate according to any one of the above [1] to [4], wherein Pa. [6] The laminate according to any one of the above [1] to [5], wherein the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) is 5 N / 15 mm width or less. [7] The laminate according to any one of the above [1] to [6], wherein the carrier sheet (B) comprises a polyester film. [8] The laminate according to any one of the above [1] to [7], wherein the carrier sheet (B) includes a release layer. [9] The laminate according to any one of the above [1] to [8], wherein the epoxy resin sheet (A) has a structure derived from a curing agent containing a polyetheramine and / or an alicyclic structure.

[10] The laminate according to any one of the above [1] to [9], wherein the epoxy resin constituting the epoxy resin sheet (A) is an epoxy resin containing a rubber component.

[11] The laminate according to any one of the above [1] to [9], wherein the epoxy resin constituting the epoxy resin sheet (A) has a block structure of a rigid component and a flexible component.

[12] The laminate according to any one of the above [1] to

[11] , wherein the epoxy resin sheet (A) has a thickness of 10 to 500 μm.

[13] The laminate according to any one of the above [1] to

[12] , wherein the carrier sheet (B) is provided on both sides of the epoxy resin sheet (A).

[14] A laminate obtained by peeling off the carrier sheet (B) from one side of the laminate according to

[13] above.

[15] A flexible or stretchable laminate using the epoxy resin sheet (A) of the laminate according to any one of the above [1] to

[14] .

[16] A fiber-reinforced composite material using the epoxy resin sheet (A) of the laminate according to any one of the above [1] to

[14] .

[17] Mobile objects such as aircraft, automobiles, ships and railway vehicles, sporting goods, home appliances and building materials, which are made using the fiber-reinforced composite material described in

[16] above.

[18] A method for producing an epoxy resin sheet, comprising a step of peeling off the carrier sheet (B) from the laminate according to any one of the above [1] to

[14] to obtain the epoxy resin sheet (A). [Effects of the Invention]

[0010] The laminate of the present invention can provide an epoxy resin sheet that has excellent stretchability even in a low-temperature environment and excellent impact resistance. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described below based on embodiments, but the present invention is not limited to the embodiments described below.

[0012] [Summary of the Invention] The laminate of the present invention comprises an epoxy resin sheet (A) and a carrier sheet (B) on at least one side of the epoxy resin sheet (A), wherein the epoxy resin sheet (A) has at least one maximum loss tangent (tanδ) in the range of -100°C to 10°C as obtained by dynamic viscoelasticity measurement in a tensile mode at a frequency of 1 Hz, and the epoxy resin sheet (A) has a tensile elongation of 50% or more.

[0013] By providing a carrier sheet (B) on at least one side of the epoxy resin sheet (A), the laminate of the present invention can prevent the epoxy resin sheet (A) from stretching, warping, wrinkling, etc. when subjected to a continuous secondary processing step such as roll-to-roll.

[0014] The tensile elongation of the epoxy resin sheet (A) of the present invention is 50% or more. On the other hand, the tensile elongation of a general epoxy resin sheet is about 10%. Therefore, the epoxy resin sheet (A) of the present invention is much more flexible than a general epoxy resin sheet and can be positioned as a special epoxy resin sheet.

[0015] The epoxy resin sheet (A) of the present invention has at least one maximum loss tangent (tanδ) in the range of -100°C to 10°C when measured for dynamic viscoelasticity in a tensile mode at a frequency of 1 Hz, and therefore has excellent elasticity even in low-temperature environments.

[0016] The epoxy resin sheet (A) and the carrier sheet (B) included in the laminate of the present invention will be described in detail below.

[0017] <Epoxy resin sheet (A)> 1. Physical properties The epoxy resin sheet (A) according to the present invention (hereinafter also referred to as "epoxy resin sheet (A)" or resin sheet (A)) is a sheet having at least one maximum value of loss tangent (tan δ) in the range of -100°C to 10°C as obtained by dynamic viscoelasticity measurement in a tensile mode at a frequency of 1 Hz, and having a tensile elongation of 50% or more, and thus having excellent elasticity.

[0018] (maximum value of tanδ) The epoxy resin sheet (A) has at least one maximum value of loss tangent (tan δ) in the range of -100°C to 10°C, as determined by dynamic viscoelasticity measurement in a tensile mode at a frequency of 1 Hz. The temperature range in which at least one maximum value of tan δ exists is preferably -80°C to 10°C, more preferably -60°C to 10°C, and even more preferably -40°C to 10°C. Since the epoxy resin sheet (A) has at least one maximum value of tan δ in the above temperature range, it has excellent stretchability even in low-temperature environments, as described above. The maximum value of the loss tangent (tan δ) obtained by measuring the dynamic viscoelasticity of the epoxy resin sheet (A) in a tensile mode at a frequency of 1 Hz can be specifically measured by the method described in the Examples.

[0019] The maximum value of loss tangent (tanδ) in the range of -100°C to 10°C obtained by dynamic viscoelastic measurement of the epoxy resin sheet (A) in a tensile mode at a frequency of 1 Hz is preferably 0.10 or more, more preferably 0.30 or more, even more preferably 0.50 or more, even more preferably 0.80 or more, and even more preferably 1.0 or more. The larger the value, the better the impact absorption. The upper limit is not particularly limited, but is preferably 5.

[0020] (tanδ) The loss tangent (tanδ) of the epoxy resin sheet (A) at -40°C to 40°C, as determined by dynamic viscoelasticity measurement in a tensile mode at a frequency of 1 Hz, is preferably 0.03 or more, more preferably 0.04 or more. When the tanδ of the epoxy resin sheet (A) at -40°C to 40°C is within the above range, the sheet has excellent impact resistance. The upper limit of the loss tangent (tanδ) is not particularly limited, but is preferably 5. The loss tangent (tan δ) at −40° C. to 40° C. obtained by dynamic viscoelastic measurement of the epoxy resin sheet (A) in a tensile mode at a frequency of 1 Hz can be specifically measured by the method described in the Examples.

[0021] (Tensile elongation) The epoxy resin sheet (A) has excellent elasticity, and the tensile elongation of the epoxy resin sheet (A) is 50% or more, preferably 80% or more, more preferably 100% or more, even more preferably 150% or more, still more preferably 160% or more, and still more preferably 170% or more. The upper limit is preferably 500% or less. The tensile elongation of the epoxy resin sheet (A) can be measured specifically by the method described in the examples.

[0022] (Stress when tensile elongation is 50%) From the viewpoint of good flexibility (stretchability), the epoxy resin sheet (A) has a stress at a tensile elongation of 50% of preferably 0.80 MPa or more, more preferably 0.90 MPa or more, and the upper limit thereof is preferably 50.0 MPa or less. From the viewpoint of energy saving, the ratio of the stress at a tensile elongation of 50% at −20° C. to the stress at a tensile elongation of 50% at 20° C. is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less. The lower limit is usually 0.95 or more. The stress when the tensile elongation of the epoxy resin sheet (A) is 50% can be measured specifically by the method described in the examples.

[0023] (tensile storage modulus) The tensile storage modulus of the epoxy resin sheet (A) at −20 to 100° C. is preferably 5.0×10 5 ~1.0×10 9 Pa, more preferably 1.0×10 6 ~9.0×10 8 Pa, and more preferably 2.0 × 10 6 ~7.0×10 8 The tensile storage modulus at -20 to 100°C is 5.0 × 10 5 ~1.0×10 9 "Pa" means that the tensile storage modulus is 5.0 x 10 over the entire temperature range of -20 to 100°C. 5 Pa or more and 1.0 x 10 9 This means that the tensile storage modulus of the epoxy resin sheet (A) at -20 to 100°C is maintained at a value of 0.05 Pa or less. Other numerical ranges are treated similarly. When the tensile storage modulus of the epoxy resin sheet (A) at -20 to 100°C is within the above range, the mechanical properties are less susceptible to sudden changes due to changes in the temperature of the environment in which it is used, and the stretchability can be maintained particularly in low-temperature environments. The tensile storage modulus of the epoxy resin sheet (A) can be specifically measured by the method described in the examples.

[0024] (Thickness) The thickness of the epoxy resin sheet (A) is preferably 10 to 500 μm, more preferably 20 to 400 μm, even more preferably 30 to 300 μm, and still more preferably 50 to 200 μm. The thickness (average thickness) of the epoxy resin sheet (A) is measured with a micrometer and calculated as the arithmetic mean.

[0025] 2. Form of epoxy resin sheet (A) The epoxy resin sheet (A) is a sheet-like molded article made of a cured product obtained by curing an epoxy resin composition. The term "curing" as used herein means intentionally curing the epoxy resin in the epoxy resin composition by heat and / or light, etc., and also includes the case where the epoxy resin sheet (A) before curing is stored for a long period of time and gradually hardens due to the influence of heat and light over time.

[0026] In this specification, the term "epoxy resin" refers to both the raw resin before curing and the resin after curing (cured product). Since the epoxy groups are consumed in the curing reaction, the cured resin may not have epoxy groups (epoxy structure), but this specification does not distinguish between them.

[0027] The epoxy resin sheet (A) preferably has a structure derived from a curing agent containing a polyetheramine and / or an alicyclic structure. The epoxy resin sheet (A) has this structure, which gives it high light transmittance and reduces coloration. The structure can be analyzed by a conventionally known method.

[0028] The epoxy resin composition (hereinafter also referred to as "epoxy resin composition (a)") that is preferably used in the present invention will be described in detail below. However, the epoxy resin composition that can be used in the present invention is not limited to the following epoxy resin composition (a).

[0029] (1) Epoxy resin composition (a) The epoxy resin composition (a) contains at least an epoxy resin and a curing agent, and may contain a solvent and other components as needed. The epoxy resin, curing agent, solvent and other components will be described in detail below.

[0030] (1-1) Epoxy resin In the present invention, the epoxy resin composition (a) preferably contains, as the epoxy resin, an epoxy resin having a block structure of a rigid component and a flexible component, and / or an epoxy resin having a rubber component such as a terminally reactive butadiene-acrylonitrile copolymer (hereinafter also referred to as a "rubber-modified epoxy resin"). Hereinafter, the epoxy resin having a block structure of a rigid component and a flexible component, and the rubber-modified epoxy resin (hereinafter, these two may be referred to as "epoxy resin (α)") will be described in detail.

[0031] (Epoxy resin with a block structure of rigid and flexible components) The rigid component of the epoxy resin preferably contains a ring structure having aromaticity, for example, a condensed aromatic ring structure such as a benzene ring, a naphthalene ring, an anthracene ring, or a pyrene ring, a structure containing multiple aromatic ring structures such as a biphenol ring, a cardo structure, or a fluorene ring, or a heterocyclic structure such as a pyrrole ring or a thiophene ring. The soft component of the epoxy resin preferably contains an aliphatic hydrocarbon, for example, an alkylene group having 1 to 8 carbon atoms, an ethylene glycol group, a propylene glycol group, or a butylene glycol group. When the epoxy resin composition (a) contains an epoxy resin having such a rigid component and a flexible component, it becomes possible to impart flexibility to the cured product.

[0032] The epoxy resin (α) does not necessarily have to have an epoxy group or an epoxy group-derived structure in both the rigid component and the flexible component. In other words, when the epoxy resin (α) has a block structure of a rigid component and a flexible component, it is sufficient that at least one of the rigid component or the flexible component has an epoxy group or an epoxy group-derived structure. From the viewpoint of imparting flexibility while retaining the inherent properties of epoxy resins, such as heat resistance and mechanical strength, it is preferable that only one of the rigid component or the flexible component has an epoxy group or an epoxy group-derived structure.

[0033] Examples of the epoxy resin (α) having a block structure of a rigid component and a flexible component include a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether, a copolymer of 1,6-hexanediol and bisphenol F diglycidyl ether, a copolymer of bisphenol F and 1,4-butanediol diglycidyl ether, a copolymer of 1,4-butanediol and bisphenol F diglycidyl ether, a copolymer of bisphenol A and 1,6-hexanediol diglycidyl ether, a copolymer of 1,6-hexanediol and bisphenol A diglycidyl ether, and a copolymer of bisphenol A diglycidyl ether. Copolymer of bisphenol A and 1,4-butanediol diglycidyl ether, copolymer of 1,4-butanediol and bisphenol A diglycidyl ether, copolymer of tetramethylbiphenol and 1,6-hexanediol diglycidyl ether, copolymer of 1,6-hexanediol and tetramethylbiphenol diglycidyl ether, copolymer of tetramethylbiphenol and 1,4-butanediol diglycidyl ether, copolymer of 1,4-butanediol and tetramethylbiphenol diglycidyl ether copolymers of biphenol and 1,6-hexanediol diglycidyl ether, copolymers of 1,6-hexanediol and biphenol diglycidyl ether, copolymers of biphenol and 1,4-butanediol diglycidyl ether, copolymers of 1,4-butanediol and biphenol diglycidyl ether, copolymers of 1,4-naphthalenediol and 1,6-hexanediol diglycidyl ether, copolymers of 1,6-hexanediol and 1,4-naphthalenediol diglycidyl ether, 1,4-naphthalenediol and 1,4-butanediol diglycidyl ether, a copolymer of 1,4-butanediol and 1,4-naphthalenediol diglycidyl ether, a copolymer of 1,6-naphthalenediol and 1,6-hexanediol diglycidyl ether, a copolymer of 1,6-hexanediol and 1,6-naphthalenediol diglycidyl ether, a copolymer of 1,6-naphthalenediol and 1,4-butanediol diglycidyl ether, a copolymer of 1,4-butanediol and 1,6-naphthalenediol diglycidyl ether, and the like. These may be used alone or in any combination and ratio of two or more. Among these, from the viewpoint of flexibility, the epoxy resin (α) preferably contains a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether.

[0034] (rubber-modified epoxy resin) In epoxy resins (rubber-modified epoxy resins) having a rubber component such as a terminally reactive butadiene-acrylonitrile copolymer, examples of the rubber component include butadiene-acrylonitrile copolymer rubber and styrene-butadiene copolymer rubber, and the polymer terminals may be carboxy-, amino-, or hydroxy-modified. In addition, known epoxy resins can be used in rubber-modified epoxy resins, including bisphenol A epoxy compounds, bisphenol F epoxy compounds, polyfunctional glycidyl ether epoxy compounds, aromatic epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds. Specific examples of rubber-modified epoxy resins include epoxy resins that have an acrylonitrile polybutadiene skeleton in the main chain and contain epoxy groups or functional groups that react with epoxy groups (e.g., amino groups, carboxy groups, hydroxy groups, etc.) at the terminals. As the rubber-modified epoxy resin, a commercially available product such as "ADEKA RESIN EPR Series" manufactured by ADEKA Corporation can be used. The epoxy resin (α) may be used alone or in combination of two or more.

[0035] The epoxy resin composition (a) may contain, as the epoxy resin, an epoxy resin other than the above-mentioned epoxy resin (α) (hereinafter referred to as "epoxy resin (β)"). As the epoxy resin (β), it is preferable to use a compound having two or more epoxy groups in the molecule.

[0036] Examples of bifunctional epoxy compounds having two epoxy groups include bisphenol-based diglycidyl ethers such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol E diglycidyl ether, bisphenol Z diglycidyl ether, bisphenol S diglycidyl ether, bisphenol AD ​​diglycidyl ether, bisphenol acetophenone diglycidyl ether, bisphenol trimethylcyclohexane diglycidyl ether, bisphenol fluorene diglycidyl ether, tetramethyl bisphenol A diglycidyl ether, tetramethyl bisphenol F diglycidyl ether, tetra-t-butyl bisphenol A diglycidyl ether, and tetramethyl bisphenol S diglycidyl ether; biphenol-based diglycidyl ethers such as biphenol diglycidyl ether, tetramethyl biphenol diglycidyl ether, dimethyl biphenol diglycidyl ether, and tetra-t-butyl biphenol diglycidyl ether; and hydroquinone diglycidyl. benzenediol diglycidyl ethers such as ether, dihydroanthracene diglycidyl ether, methylhydroquinone diglycidyl ether, dibutylhydroquinone diglycidyl ether, resorcinol diglycidyl ether, and methylresorcinol diglycidyl ether; aromatic diglycidyl ethers such as dihydroanthrahydroquinone diglycidyl ether, dihydroxydiphenyl ether diglycidyl ether, thiodiphenol diglycidyl ether, and dihydroxynaphthalene diglycidyl ether; epoxy compounds in which hydrogen is added to the aromatic ring of a diglycidyl ether selected from the above-mentioned bisphenol diglycidyl ethers, biphenol diglycidyl ethers, benzenediol diglycidyl ethers, and aromatic diglycidyl ethers; epoxy resins produced from various carboxylic acids, such as adipic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, biphenyldicarboxylic acid, and dimer acid, and epihalohydrin;Examples of (poly)alkylene glycol diglycidyl ethers consisting only of a chain structure include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, 1,5-pentanediol diglycidyl ether, polypentamethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, 1,7-heptanediol diglycidyl ether, polyheptamethylene glycol diglycidyl ether, 1,8-octanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, and 2,2-dimethyl-1,3-propanediol diglycidyl ether; and alkylene glycol diglycidyl ethers having a cyclic structure, such as 1,4-cyclohexanedimethanol diglycidyl ether.

[0037] Examples of tri- or higher functional epoxy compounds having three or more epoxy groups include the following: In the following examples, "... type epoxy resin" refers to one in which a hydroxyl group has been substituted with a glycidyl ether group. For example, "4,4',4"-trihydroxytriphenylmethane type epoxy resin" refers to one in which the hydroxyl group of "4,4',4"-trihydroxytriphenylmethane" has been substituted with a glycidyl ether group.

[0038] α,α-Bis(4-hydroxyphenyl)-4-(4-hydroxy-α,α-dimethylbenzyl)-ethylbenzene type epoxy resin, 4,4',4''-trihydroxytriphenylmethane type epoxy resin, 4,4',4''-ethylidinetris(2-methylphenol) type epoxy resin, 4,4'-(2-hydroxybenzylidene)bis(2,3,6-trimethylphenol) type epoxy resin, 2,3,4-trihydroxydiphenylmethane type epoxy resin, 2,4,6-tris(4,hydroxyphenyl)-1,3,5-triazine type epoxy resin, 1,3,5-tris(4-hydroxyphenyl)benzene type epoxy resin, 1,1,1-tris(4-hydroxyphenyl)ethane type epoxy resin, 4,4'-[1-[4-[1-(4-hydroxy-3,5-dimethylphenyl)-1-methylethyl]phenyl]ethylidene]bis(2-methylphenol) type epoxy resin, 2,6-bis(4 trifunctional epoxy resins such as 2,2'-methylenebis[6-(2-hydroxy-5-methylbenzyl)-p-cresol]-type epoxy resins, 4-[bis(4-hydroxy-3-methylphenyl)methyl]benzene-1,2-diol-type epoxy resins, 1,1,2,2-tetrakis(p-hydroxyphenyl)ethane-type epoxy resins, and α,α,α',α'-tetrakis(4-hydroxyphenyl)-p-xylene-type epoxy resins; pentafunctional epoxy resins such as 2,4,6-tris[(4-hydroxyphenyl)methyl]-1,3-benzenediol-type epoxy resins; epoxy compounds produced from epihalohydrin and various amine compounds such as diaminodiphenylmethane, aminophenol, and xylenediamine; epoxy compounds produced from epihalohydrin and aliphatic polyols;Examples of the epoxy resins include phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, naphthol novolac epoxy resins, phenol aralkyl epoxy resins, biphenyl aralkyl epoxy resins, and phenol-modified xylene epoxy resins, as well as polyhydric phenol resins obtained by condensation reactions of these various phenols with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde, and glyoxal, and polyfunctional epoxy resins such as epoxy resins using various phenolic compounds, such as co-condensation resins of heavy oils or pitches with phenols and formaldehydes;

[0039] Among these, it is preferable to use a bifunctional epoxy compound as the epoxy resin (β) from the viewpoint of preventing gelation during the production of the epoxy resin of the present invention. Furthermore, from the viewpoint of obtaining good flexibility, it is preferable to use bisphenol-based diglycidyl ethers, biphenol-based diglycidyl ethers, polyalkylene polyol-based diglycidyl ethers, epoxy compounds in which hydrogen has been added to the aromatic ring of bisphenol-based diglycidyl ethers, and epoxy compounds in which hydrogen has been added to the aromatic ring of biphenol-based diglycidyl ethers, and among these, polyalkylene polyol-based diglycidyl ethers, epoxy compounds in which hydrogen has been added to the aromatic ring of bisphenol-based diglycidyl ethers, and epoxy compounds in which hydrogen has been added to the aromatic ring of biphenol-based diglycidyl ethers are more preferable. These may be used singly or as a mixture of two or more kinds in any combination and ratio.

[0040] The epoxy resin composition (a) may contain only the epoxy resin (α), may contain both the epoxy resin (α) and the epoxy resin (β), or may contain only the epoxy resin (β).

[0041] When the epoxy resin composition (a) contains an epoxy resin (α) and an epoxy resin (β), the proportion of the epoxy resin (β) in the total epoxy components as solid content in the epoxy resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and the upper limit is preferably 95% by mass or less, more preferably 90% by mass or less. When the proportion of the epoxy resin (β) is equal to or greater than the lower limit, the effect of improving physical properties due to the incorporation of the epoxy resin (β) can be sufficiently obtained. On the other hand, when the proportion of the epoxy resin (β) is equal to or less than the upper limit, the effect of imparting flexibility and improving flexibility due to the epoxy resin (α) can be sufficiently obtained.

[0042] In the present invention, the term "solid content" means components excluding the solvent, and includes not only solid epoxy resins or epoxy compounds, but also semi-solid and viscous liquid substances. Furthermore, the term "total epoxy components" means the total of the epoxy resin (α) and the above-mentioned epoxy resin (β).

[0043] (1-2) Hardener The curing agent used in the present invention is one that contributes to the crosslinking reaction between the epoxy group of the epoxy resin and the group reactive with the epoxy group. There are no particular limitations on the curing agent, and any curing agent generally known as an epoxy resin curing agent can be used. Examples of such curing agents include phenol-based curing agents, amine-based curing agents such as aliphatic amines, polyether amines, alicyclic amines, and aromatic amines, acid anhydride-based curing agents, amide-based curing agents, tertiary amines, imidazole and its derivatives, organic phosphines, phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, boron halide amine complexes, polymercaptan-based curing agents, isocyanate-based curing agents, and blocked isocyanate-based curing agents. These may be used alone or in any combination and ratio of two or more. Among these, from the viewpoints of high transparency and little coloration, curing agents having an alicyclic structure such as polyetheramine, alicyclic polyamine, and alicyclic acid anhydride are preferred, and curing agents having an alicyclic structure are more preferred.

[0044] Examples of polyetheramines include triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis(propylamine), trimethylolpropane(oxypropylene)triamine, polyoxypropylene diamine, and polyoxypropylene triamines.

[0045] Commercially available polyetheramines may be used, such as those available under the trade name "Jeffamine Series" manufactured by Huntsman.

[0046] The curing agent having an alicyclic structure may be any substance that has an alicyclic structure and contributes to the crosslinking reaction and / or chain extension reaction between epoxy groups of the epoxy resin. Specific examples include alicyclic polyamines and alicyclic acid anhydrides. More specifically, examples of the alicyclic polyamines include 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-7-ene, N,N'-dimethylpiperazine, N-aminoethylpiperazine, menthene diamine, isophorone diamine, hexamethylenetetramine, methylenebis(cyclohexanamine), 1,3-bis(aminomethyl)cyclohexane, norbornene diamine, 1,2-diaminocyclohexane, and modified alicyclic polyamines obtained by epoxy-modifying, ethylene oxide-modifying, dimer acid-modifying, Mannich-modifying, Michael addition-modifying, thiourea condensing-modifying, or ketiminizing these alicyclic polyamines. Examples of the alicyclic acid anhydrides include hexahydrophthalic anhydride and methylhexahydrophthalic anhydride. Of these, alicyclic polyamines are preferred, and among these, isophoronediamine, hexamethylenetetramine, methylenebis(cyclohexanamine), 1,3-bis(aminomethyl)cyclohexane, norbornenediamine, 1,2-diaminocyclohexane, and modified products thereof are particularly preferred.

[0047] As the curing agent having an alicyclic structure, commercially available products can be used, such as those manufactured by Mitsubishi Chemical Corporation under the trade names "jER Cure 113" and "jER Cure ST-14," and those manufactured by New Japan Chemical Co., Ltd. under the trade name "Rikacid MH-700."

[0048] The content of the curing agent in the epoxy resin composition (a) (when a curing agent other than the curing agent having an alicyclic structure is used, the total content of the curing agent having an alicyclic structure and the other curing agent) is preferably 0.1 to 100 parts by mass, more preferably 80 parts by mass or less, even more preferably 60 parts by mass or less, and particularly preferably 40 parts by mass or less, per 100 parts by mass of the epoxy resin (total content of all epoxy components).

[0049] (1-3) Solvent The epoxy resin composition (a) may be diluted by blending a solvent to adjust the viscosity of the epoxy resin composition appropriately when handling it for forming a coating film, etc. The solvent in the epoxy resin composition (a) is used to ensure the ease of handling and workability when molding the epoxy resin composition, and there is no particular limitation on the amount used. In the present invention, the terms "solvent" and "solvents" are used to distinguish between them depending on the form of use, but the same or different types may be used independently.

[0050] Examples of solvents that may be contained in the epoxy resin composition (a) include acetone, methyl ethyl ketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate, ethylene glycol monomethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, methanol, and ethanol. These solvents may also be used as a mixed solvent of two or more kinds, as appropriate.

[0051] (1-4) Other ingredients The epoxy resin composition (a) may contain other components in addition to the components listed above. The other components can be used in appropriate combination depending on the desired physical properties of the epoxy resin composition.

[0052] For example, it is preferable to add a thermosetting resin modifier to the epoxy resin composition (a) from the viewpoint of maintaining flexibility and improving water resistance. Examples of the modifier include terminally reactive butadiene-acrylonitrile copolymer. The amount of the modifier to be added is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the sum of the epoxy resin and the curing agent. The lower limit is not particularly limited, but is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.0 part by mass or more. Commercially available modifiers include amino-terminated butadiene-acrylonitrile copolymers such as "Hypro 1300X16 ATBN" and "Hypro 1300X42 ATBN"; carboxy-terminated butadiene-acrylonitrile copolymers such as "Hypro 1300X8 CTBN" and "Hypro 1300X31 CTBN"; and epoxy-terminated butadiene-acrylonitrile copolymer "HyproRA840" (all manufactured by Huntsman).

[0053] Furthermore, for the purpose of improving various properties such as the effect of reducing the cure shrinkage rate and the effect of reducing the thermal expansion rate of the obtained cured product, an inorganic filler can be further added to the epoxy resin composition (a), and application development can be promoted in the electrical and electronic fields, particularly as a liquid semiconductor encapsulant. Furthermore, an organic filler such as rubber particles or acrylic particles can also be added to the epoxy resin composition (a) to impart toughness.

[0054] Examples of inorganic fillers include powdered reinforcing materials and fillers, for example, metal oxides such as aluminum oxide and magnesium oxide, metal carbonates such as calcium carbonate and magnesium carbonate, silicon compounds such as diatomaceous earth powder, basic magnesium silicate, calcined clay, finely powdered silica, fused silica and zeolite, metal hydroxides such as aluminum hydroxide, and others, such as kaolin, mica, quartz powder, graphite, carbon black, carbon nanotubes, molybdenum disulfide, boron nitride and aluminum nitride.

[0055] Fibrous reinforcing materials or fillers can be added to the epoxy resin composition (a). Examples include glass fibers, ceramic fibers, carbon fibers, alumina fibers, silicon carbide fibers, boron fibers, aramid fibers, cellulose nanofibers, and cellulose nanocrystals. Organic or inorganic fiber cloth or nonwoven fabric can also be used.

[0056] These fillers, fibers, cloths and nonwoven fabrics may be surface-treated with a silane coupling agent, titanate coupling agent, aluminate coupling agent or primer.

[0057] When an inorganic filler, fibrous reinforcing material, or filler is added to the epoxy resin composition (a), the total amount of these added is preferably 900 parts by mass or less, more preferably 700 parts by mass or less, and even more preferably 500 parts by mass or less, per 100 parts by mass of the epoxy resin and curing agent. The lower limit is not particularly limited, but is preferably 1 part by mass, more preferably 5 parts by mass, and even more preferably 10 parts by mass.

[0058] The epoxy resin composition (a) may contain, as required, a coupling agent, a plasticizer, a diluent, a flexibility-imparting agent, a dispersant, a wetting agent, a colorant, a pigment, an ultraviolet absorber, a light stabilizer such as a hindered amine-based light stabilizer, an antioxidant, a defoaming agent, a mold release agent, a flow control agent, and the like. The amount of these components added is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the sum of the epoxy resin and the curing agent. The lower limit is not particularly limited, but is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and even more preferably 1.0 part by mass or more.

[0059] The epoxy resin composition (a) may optionally contain various curable monomers, oligomers and synthetic resins in order to improve the properties of the resin in the final coating film. For example, cyanate ester resin, acrylic resin, silicone resin, polyester resin, etc. may be used alone or in combination of two or more thereof. The blending ratio of these resins is an amount within a range that does not impair the inherent properties of the epoxy resin composition (a), i.e., per 100 parts by mass of the sum of the epoxy resin and the curing agent, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. The lower limit is not particularly limited, but is preferably 1.0 part by mass or more, more preferably 5.0 parts by mass or more, and even more preferably 10 parts by mass or more.

[0060] (2) Preferred embodiment The epoxy resin sheet (A) according to the present invention preferably comprises a cured product obtained by curing an epoxy resin composition containing an epoxy resin and a curing agent having a polyetheramine and / or an alicyclic structure, more preferably a cured product obtained by curing an epoxy resin and a polyetheramine. The epoxy resin preferably contains an epoxy resin or a rubber-modified epoxy resin having a block structure of a rigid component and a flexible component, more preferably a rubber-modified epoxy resin, and even more preferably a rubber-modified epoxy resin having an acrylonitrile polybutadiene skeleton in the main chain and containing an epoxy group or a functional group reactive with an epoxy group (e.g., an amino group, a carboxy group, a hydroxy group, etc.) at the terminal.

[0061] <Carrier Sheet (B)> 1. Physical properties In the present invention, the thickness of the carrier sheet (B) is preferably 1 to 500 μm, more preferably 5 to 300 μm, even more preferably 10 to 150 μm, and even more preferably 20 to 120 μm. The thickness (average thickness) of the carrier sheet (B) is measured with a micrometer and calculated as the arithmetic mean of the measured values. Here, when the laminate of the present invention is a laminate comprising a carrier sheet (B) on both sides of an epoxy resin sheet (A), the thickness of the carrier sheet (B) means the thickness of each sheet.

[0062] 2. Carrier sheet (B) shape In the present invention, examples of the substrate for the carrier sheet (B) include thin sheets made of paper, resin, metal, etc. The carrier sheet (B) is preferably a sheet of paper or resin, particularly from the viewpoints of low cost, ease of processing, and ease of disposal or recycling, and more preferably a resin from the viewpoint of transparency. In general, a "sheet" is defined in JIS as a thin, flat product whose thickness is small relative to its length and width, and a "film" is generally a thin, flat product whose thickness is extremely small compared to its length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll (JIS K 6900:1994). However, the boundary between "sheet" and "film" is unclear, and there is no need to distinguish between the two in the present invention. Therefore, in the present invention, when the term "film" is used, it is intended to include "sheet," and when the term "sheet" is used, it is intended to include "film."

[0063] As the paper, for example, high-quality paper, kraft paper, glassine paper, parchment paper, and super-calendered kraft paper, the surface of which has been treated with a silicone coating, can be used.

[0064] The resin film may be a film whose main component is, for example, a polyolefin such as polyethylene or polypropylene, a polyester such as polyethylene terephthalate or polyethylene naphthalate, a polyimide, or a polycarbonate. The surface of these films may be coated with a silicone resin release agent or the like to adjust the peel strength. In addition, from the viewpoints of appearance, ease of processing, durability, heat resistance, cost, etc., the carrier sheet (B) preferably contains a polyester film containing polyester as a main component. The resin film may have a single layer structure or a multi-layer structure of two or more layers, provided that the structure does not deviate from the gist of the present invention. The term "main component resin" refers to the resin with the highest content among the resins constituting the base material, specifically a resin that accounts for 50% by mass or more, particularly 70% by mass or more, particularly 80% by mass or more, and particularly 90% by mass or more (including 100% by mass) of the resin.

[0065] The polyester is preferably one obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. The polyester may be a polyester composed of one type of aromatic dicarboxylic acid and one type of aliphatic glycol, or a copolymer polyester in which one or more other components are further copolymerized. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. On the other hand, examples of dicarboxylic acids used as other components of the copolymer polyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and sebacic acid, and examples of glycol components include ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, and neopentyl glycol. Also usable are oxycarboxylic acids such as p-oxybenzoic acid. Typical examples of polyesters include polyethylene terephthalate obtained by polycondensation of terephthalic acid and ethylene glycol, and polyethylene naphthalate obtained by polycondensation of 2,6-naphthalenedicarboxylic acid and ethylene glycol. The polyester film may be a non-stretched film or a stretched film, but from the viewpoint of mechanical strength, a stretched film is preferred, and a biaxially stretched film is more preferred. The polyester film may also be previously subjected to a surface treatment such as a corona treatment or a plasma treatment.

[0066] Furthermore, the carrier sheet (B) may have a structure that further includes a release layer as the outermost layer on the side that comes into contact with the epoxy resin sheet (A) in addition to the resin film. When the carrier sheet (B) further includes a release layer in addition to the resin film, it becomes easy to adjust the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) to 5 N / 15 mm width or less.

[0067] The components of the release layer are not particularly limited, and may contain silicone compounds, fluorine compounds, waxes, surfactants, etc. From the viewpoint of a good balance between cost and releasability, it is preferable to use silicone compounds. Furthermore, a release control agent may be used in combination to adjust the release properties of the release layer.

[0068] Commercially available carrier sheets (B) comprising a polyester film and a release layer include those manufactured by Teijin Film Solutions Co., Ltd. under the trade name "Purex A31" and those manufactured by Mitsubishi Chemical Corporation under the trade names "MRF-38" and "MRF-75."

[0069] <Laminate> The laminate of the present invention may comprise a carrier sheet (B) on at least one side of the epoxy resin sheet (A), or may comprise carrier sheets (B) on both sides of the epoxy resin sheet (A). Furthermore, the film may have layers other than the epoxy resin sheet (A) and the carrier sheet (B) within the scope that does not impair the effects of the present invention. Examples of layers other than the epoxy resin sheet (A) and the carrier sheet (B) include an adhesive layer, a bonding layer, a hard coat layer, a barrier layer, etc.

[0070] When carrier sheets (B) are provided on both sides of the epoxy resin sheet (A), the first carrier sheet (B1) laminated on one side of the epoxy resin sheet (A) and the second carrier sheet (B2) laminated on the other side of the epoxy resin sheet (A) may be the same as or different from each other.

[0071] In the laminate of the present invention, the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) is preferably 5 N / 15 mm width or less, more preferably 3 N / 15 mm width or less, even more preferably 2 N / 15 mm width or less, and even more preferably 1 N / 15 mm width or less. The lower limit is preferably 0.01 N / 15 mm width or more. When the peel strength is within the above numerical range, the peel surface of the epoxy resin sheet (A) does not tear or chip when the carrier sheet (B) is peeled from the epoxy resin sheet (A), and an epoxy resin sheet or laminate having excellent elasticity can be easily obtained. In addition, when carrier sheets (B) are provided on both sides of the epoxy resin sheet (A), at least one of the peel strength between the epoxy resin sheet (A) and the first carrier sheet (B1) and the peel strength between the epoxy resin sheet (A) and the second carrier sheet (B2) should be within the above numerical range. That is, at least one of the first carrier sheet (B1) and the second carrier sheet (B2) needs to be release-treated, and the other may be a general sheet that is not release-treated.

[0072] The tensile storage modulus of the laminate of the present invention at 20 to 100°C is preferably 6.0 × 10 7 ~5.0×10 10 Pa, more preferably 1.0×10 8 ~1.0×10 10 Pa, and more preferably 5.0 × 10 8 ~1.0×10 10 It is Pa. When the laminate has such a tensile storage modulus, problems such as elongation, deflection, and wrinkle formation of the epoxy resin sheet during secondary processing can be suppressed, and handling properties can be improved. More specifically, if the tensile storage modulus of the laminate at 20°C to 100°C is equal to or greater than the lower limit, not only is the occurrence of warping and wrinkling suppressed even if the epoxy resin sheet (A) is flexible, but also, for example, when the laminate is punched, the laminate does not stick to a punching blade, and the dimensional stability of the punched part is also good. Furthermore, if the tensile storage modulus of the laminate at 20°C to 100°C is equal to or less than the above upper limit, it is easy to form the laminate into a wound (roll) shape, and even when the laminate is stored in the wound state for a long period of time and then unwound for secondary processing, it can maintain the same shape (thickness variation, etc.) and various properties as when it was first manufactured. The tensile storage modulus of the laminate can be measured specifically by the method described in the examples.

[0073] The thickness of the laminate of the present invention is preferably 30 to 1000 μm, more preferably 50 to 500 μm, even more preferably 80 to 400 μm, and even more preferably 100 to 380 μm. The thickness (average thickness) of the laminate is measured with a micrometer and calculated as the arithmetic mean of the measured values.

[0074] <Method of manufacturing laminate> The method for producing the laminate of the present invention is not particularly limited, but preferably includes a step of applying a resin composition for the epoxy resin sheet (A) (hereinafter also referred to as "epoxy resin composition") onto a carrier sheet (B) and curing the epoxy resin composition to form the epoxy resin sheet (A). When a laminate having carrier sheets (B) on both sides of an epoxy resin sheet (A) is produced, the following production methods 1 and 2 may be used. Manufacturing method 1: A method in which an epoxy resin composition is applied onto a first carrier sheet (B1), the epoxy resin composition is cured to form an epoxy resin sheet (A), and then a second carrier sheet (B2) is laminated to the surface of the epoxy resin sheet (A) opposite to the surface on which the first carrier sheet (B1) is provided. Manufacturing method 2: A method in which an epoxy resin composition is applied onto a first carrier sheet (B1), a second carrier sheet (B2) is laminated to the surface of the epoxy resin composition opposite to the surface on which the first carrier sheet (B1) is provided, and the epoxy resin composition is cured to form an epoxy resin sheet (A).

[0075] The epoxy resin sheet (A) can be produced by curing an epoxy resin composition in a sheet shape of a predetermined thickness, or by forming a semi-cured product obtained from the epoxy resin composition into a sheet shape of a predetermined thickness and further curing the sheet.

[0076] The method for curing the epoxy resin composition varies depending on the components and amounts of the components in the epoxy resin composition and the shape of the compounded product (e.g., sheet thickness), but typically involves heating at 23 to 200°C for 5 minutes to 24 hours. This heating is preferably carried out in two stages: primary heating at 20 to 160°C for 5 minutes to 24 hours, and secondary heating at 60 to 200°C, which is 40 to 180°C higher than the primary heating temperature, for 5 minutes to 24 hours. To reduce poor curing, a three-stage process may be carried out in which tertiary heating is carried out at 100 to 200°C, which is higher than the secondary heating temperature, for 5 minutes to 24 hours.

[0077] When producing a cured product as a semi-cured product, the curing reaction of the epoxy resin composition may be allowed to proceed to an extent that allows the shape to be maintained by heating, etc. When the epoxy resin composition contains a solvent, most of the solvent is removed by techniques such as heating, decompression, and air drying, but 5% by mass or less of the solvent may remain in the semi-cured product. The epoxy resin sheet (A) of the present invention may be in a semi-cured state as long as the tensile elongation is within the above-mentioned range. If the epoxy resin sheet (A) is in a semi-cured state, it may be easier to form it into a wound body or the secondary processability may be improved.

[0078] The laminate of the present invention may be produced by producing a laminate having a carrier sheet (B) on both sides of an epoxy resin sheet (A), and then peeling off the carrier sheet (B) from at least one side of the obtained laminate. That is, the method for producing the laminate of the present invention may include a step of peeling off the carrier sheet (B) from at least one surface of the laminate.

[0079] Alternatively, the epoxy resin sheet (A) may be obtained by peeling off the carrier sheet (B) from the laminate of the present invention. That is, the method for producing the epoxy resin sheet (A) in the present invention includes a step of peeling off the carrier sheet (B) from the laminate to obtain the epoxy resin sheet (A).

[0080] The epoxy resin sheet (A) or laminate obtained by the production method of the present invention has an intact surface appearance and can therefore be suitably used in applications requiring precision, such as in the electrical and electronic fields, for example, as flexible or stretchable laminates where flexibility is important.

[0081] Examples of flexible laminates or stretchable laminates include printed wiring boards laminated with metal foils such as copper foils. An example of a method for producing a printed wiring board is a method in which copper foil is layered on one or both sides of an epoxy resin sheet (A), and hot press molding is performed using a vacuum press or the like to produce a copper-clad laminate, and a wiring pattern is formed by etching to obtain a printed wiring board. Examples of wiring patterns include printed wiring boards using conductive paste. One example is a method of forming a wiring pattern by applying a conductive paste to one or both sides of an epoxy resin sheet (A) using a known method such as screen printing or inkjet printing to obtain a printed wiring board. The conductive paste is preferably flexible and stretchable. By mounting various electronic elements on the printed wiring board, it is possible to obtain a flexible or stretchable device.

[0082] The epoxy resin sheet (A) obtained by the production method of the present invention can also be used, for example, as a fiber-reinforced composite material containing a resin component and reinforcing fibers, preferably as a laminate with prepreg and / or semipreg. These fiber-reinforced composites and laminates have excellent impact resistance and heat resistance, as well as excellent vibration damping and interlayer adhesion, and are therefore suitable for use in mobile objects such as aircraft, automobiles, ships, and railway vehicles, sporting goods, home appliances, and building materials.

[0083] In addition, the epoxy resin sheet (A) or laminate of the present invention can also be used for electronic and electrical components such as cushioning materials, pressure sensitive adhesive sheets, elastic tapes, and various sensor substrates including pressure sensors. The adhesive sheet can be used as a filler to fill the gap between an image display panel such as a liquid crystal display (LCD), plasma display (PDP), or electroluminescence display (ELD) and a panel component such as a protective panel or touch panel that is placed on the front side (viewing side) of the panel when in use. In addition to electronic and electrical component applications, the material can also be used in a variety of industrial applications, including cushioning materials, pressure-sensitive adhesive sheets, adhesive sheets, stretchable tapes, sealing sheets, heat-resistant insulating sheets, heat-resistant conductive sheets, glass substitutes, protective films, medical sheets, agricultural sheets, and construction sheets. [Example]

[0084] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. Note that the values ​​of various production conditions and evaluation results in the following examples represent preferred upper or lower limit values ​​in the embodiments of the present invention, and preferred ranges may be defined by combining the above-mentioned upper or lower limit values ​​with the values ​​in the following examples or values ​​between examples. In the following, all "parts" refer to "parts by mass."

[0085] [Various analysis, evaluation, and measurement methods] The methods for analyzing, evaluating and measuring the various physical properties and characteristics are as follows:

[0086] <Resin sheet (A)> (1) Thickness The thickness of the resin sheet (A) was measured using a micrometer, with the thickness of two carrier sheets (B) set as the reference thickness (0 μm). The thickness of an A4-sized laminate sample was measured at three locations 100 mm apart from the edge in the width direction, and the arithmetic mean value of these measurements was shown in Table 1.

[0087] (2) Tensile storage modulus (E') The carrier sheet (B) was peeled from the laminate sample, and a 15 mm wide x 50 mm long test piece was cut from the remaining resin sheet (A). The test piece was measured using a dynamic viscoelasticity measurement device ("DVA-200" manufactured by IT Measurement & Control Co., Ltd.) according to the dynamic viscoelasticity measurement method described in JIS K 7244-4:1999, at a frequency of 1 Hz, while the temperature was raised from -100°C to 150°C at a rate of 3°C / min. The tensile storage modulus E' at -20°C, -10°C, 0°C, 20°C, 40°C, and 100°C is shown in Table 1. (3) Tensile loss tangent (tanδ) The tensile loss tangent (tanδ) was determined by calculating the loss modulus E″ / storage modulus E′ from the values ​​of the loss modulus E″ and the storage modulus E′ obtained by the dynamic viscoelasticity measurement method described in (2) above. (4) Maximum value of tensile loss tangent (tanδ) When the dynamic viscoelasticity was measured between -100°C and 150°C using the dynamic viscoelasticity measurement method (2) above, the temperature at which the maximum value of the tensile loss tangent (tanδ) was obtained and the value of that maximum value are shown in Table 1.

[0088] (5) Tensile elongation The carrier sheet (B) was peeled off from the laminate sample, and the remaining resin sheet (A) was cut into a dumbbell shape with a width of 6 mm and a gauge length of 80 mm to prepare a test piece. In accordance with JIS K 7127:1999, a tensile test was performed on the test piece at a test speed of 200 mm / min under an environment of 23°C and 50% RH, and the elongation at tensile break is shown in Table 1 as the tensile elongation. Further, tensile tests were carried out in accordance with JIS K 7127:1999 in a 50% RH environment at temperatures of -20°C, 0°C, and 20°C. The stress at a tensile elongation of 50% was calculated from the obtained elongation-stress ss curve and is shown in Table 1.

[0089] (6) Impact absorption rate The carrier sheet (B) was peeled from the laminate sample, and a 50 mm wide x 50 mm long specimen was cut from the remaining resin sheet (A). A 100 μm thick cushion layer was placed on a metal stand. Pressure-sensitive paper (HS type, manufactured by Fujifilm Corporation) was placed on this cushion layer, and a metal ball with a diameter of 5 / 8 inch and a weight of 16.3 g was dropped from a height of 50 mm above the center of the specimen. The maximum stress (R) received by the pressure-sensitive paper was measured using a Fujifilm Prescale pressure image analysis system (FPD-8010J). The specimen to be evaluated was then placed on the pressure-sensitive paper, ensuring no gaps were left, and the metal ball was dropped freely in the same manner as described above. The maximum stress (S) received by the specimen was then measured. The impact absorption rate was calculated using the following formula and is shown in Table 1. Impact absorption rate (%) = (RS) / R x 100

[0090] <Laminate> (1) Thickness The thickness of the laminate was determined by calculating the sum of the thickness of the resin sheet (A) determined above and the thickness of the two carrier sheets (B). The values ​​are shown in Table 2.

[0091] (2) Tensile storage modulus (E') A test piece measuring 15 mm wide x 50 mm long was cut out from the laminate sample. Measurements were performed on the test piece using a dynamic viscoelasticity measuring device ("DVA-200" manufactured by IT Measurement & Control Co., Ltd.) according to the dynamic viscoelasticity measurement method described in JIS K 7244-4: 1999 under the conditions of a frequency of 1 Hz, a heating rate of 3°C / min, and a double-support tensile mode. The tensile storage moduli E' at 20°C, 50°C, and 100°C are shown in Table 1.

[0092] (3) Peel strength The laminate sample was cut into a size of 15 mm wide x 250 mm long to prepare a test piece, and a T-peel test was performed on the interface between the resin sheet (A) and the carrier sheet (B) using a universal material testing machine ("AGS-X" manufactured by Shimadzu Corporation) at a test speed of 50 mm / min. The average value of the peel force between displacements of 30 mm and 60 mm was taken as the peel strength.

[0093] (4) Adhesion to CFRP The separator film was removed from a carbon fiber prepreg (trade name "TR3110 381GMX" manufactured by Mitsubishi Chemical Corporation (thickness: 210-220 μm, base material: epoxy resin)), and a resin sheet (with the carrier sheet removed) was laminated on one side of the carbon fiber prepreg. The carbon fiber prepreg was then heat-pressed at 130°C for 90 minutes under a pressure of 0.8 MPa using a heat press machine to obtain a sample for evaluation. A test piece measuring 15 mm wide and 150 mm long was cut out and used to perform a 180° peel test at the interface between the cured carbon fiber prepreg and the resin sheet (A) using a universal testing machine ("AGS-X" manufactured by Shimadzu Corporation) at a test speed of 50 mm / min. The peel strength was determined and evaluated according to the following criteria. A: The interface did not peel off, and the substrate on the handle side broke. B: Peel strength is 1N / mm or more C: Peel strength is less than 1N / mm

[0094] (5) Printable adaptability The conductive paste used was an elastic silver paste "Dotite XA-9521" manufactured by Fujikura Kasei Co., Ltd., and was applied by screen printing to the 100 μm-thick resin sheets (with the carrier sheet removed) obtained in Examples 3 and 4 and Comparative Examples 1 and 3 above, to produce a resin sheet (A) / conductive layer (C) laminate. Further, by heat-treating in an oven at 100°C for 60 minutes, a laminate in which the conductive layer (C) was completely cured was obtained. The thickness of each layer of the obtained laminate was 100 μm for the resin sheet (A) and approximately 30 μm for the conductive layer (C), and both the resin sheet (A) and the conductive layer (C) were well adhered to each other. A test piece was cut out from the obtained laminate, and the resistance value was measured by the following method. The dimensions of the resin sheet (A) were 38 mm in length and 12 mm in width. The wiring shape was a dumbbell shape with a gauge length of 10 mm and a width of 5 mm (total length 36 mm, maximum width 11 mm).

[0095] -Method for measuring resistance value- The test specimen obtained by the method described above was subjected to uniaxial expansion and contraction, and the change in resistance value was measured at room temperature of 24°C. A stretching cycle test was performed using an electric slider "EAS4NY-D010-AZAAD-3" manufactured by Oriental Motor Co., Ltd., by stretching and contracting 40,000 times between elongation rates of 0 and 10%. The stretching speed during this period was 3.33 mm / sec. The maximum resistance obtained during this period was taken as Rmax. Next, the printed sample was treated at 85°C and 85% RH for 500 hours, and then subjected to a stretch cycle test under the same conditions, and the maximum resistance value was taken as Rmax'. From the obtained Rmax and Rmax', Rmax / Rmax' was calculated and evaluated according to the following criteria. A: Rmax / Rmax' is 1 or less B: Rmax / Rmax' is 2 or less C: The resistance value exceeded the measurement range and could not be measured, or measurement was not possible due to a sample defect. The resistance values ​​were measured using a Tektronix multimeter "DMM4050" using a two-wire resistance measurement method. The sampling frequency was set to 0.1 Hz and the measurement was carried out at a room temperature of 23°C.

[0096] In the examples and comparative examples, the resin sheet (A) and the laminate were prepared as follows.

[0097] <Materials used for resin sheet (A)> (Epoxy resin (α)) Epoxy resin (α1) As the epoxy resin (α1), a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether prepared by the following method was used. A 1-L glass flask equipped with a stirrer, dropping funnel, and thermometer was charged with 141.8 parts by mass of 1,6-hexanediol preheated to 45°C and 0.51 parts by mass of boron trifluoride ethyl ether, and the mixture was heated to 80°C. 244.3 parts by mass of epichlorohydrin was added dropwise over a period of time so as not to exceed 85°C. The mixture was aged for 1 hour while maintaining the temperature at 80-85°C, and then cooled to 45°C. 528.0 parts by mass of a 22% by mass aqueous sodium hydroxide solution was added, and the mixture was vigorously stirred at 45°C for 4 hours. The mixture was cooled to room temperature, the aqueous phase was separated, and the mixture was heated under reduced pressure to remove unreacted epichlorohydrin and water, yielding 283.6 parts by mass of crude 1,6-hexanediol diglycidyl ether. This crude 1,6-hexanediol diglycidyl ether was purified by distillation using an Oldershaw distillation column (15 plates), and the fraction at a pressure of 1300 Pa and 170 to 190°C was taken as the main fraction, thereby obtaining 127.6 parts by mass of 1,6-hexanediol diglycidyl ether having a diglycidyl purity of 97% by mass as determined by gas chromatography, a total chlorine content of 0.15% by mass, and an epoxy equivalent of 116 g / eq. 100 parts by mass of the 1,6-hexanediol diglycidyl ether, 69.3 parts by mass of bisphenol F (phenolic hydroxyl group equivalent: 100 g / eq), and 0.13 parts by mass of ethyltriphenylphosphonium iodide (30% by mass solution in methyl cellosolve) were placed in a pressure-resistant reaction vessel, and a polymerization reaction was carried out at 165 to 170°C for 5 hours under a nitrogen gas atmosphere, thereby obtaining a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether having an epoxy equivalent of 1,000 g / eq and a number average molecular weight of 3,000. The copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether had a block structure consisting of rigid and flexible components.

[0098] Epoxy resin (α2) Rubber-modified epoxy resin (ADEKA Corporation's product name "ADEKA Resin EPR-1630", CTBN (a butadiene-acrylonitrile copolymer epoxy resin containing carboxy groups)) Epoxy resin (α3): Bisphenol A type epoxy resin (product name "jER828" manufactured by Mitsubishi Chemical Corporation) (epoxy equivalent: 390 g / eq) was used.

[0099] (hardening agent) Hardener (C1) Alicyclic polyamine, Mitsubishi Chemical Corporation's product name "jER Cure ST-14", active hydrogen equivalent: 85g / eq Hardener (C2) Trimethylolpropane poly(oxypropylene) triamine, Huntsman Jeffamine T-403, active hydrogen equivalent: 81g / eq Hardener (C3) Polyoxypropylenediamine, Huntsman "Jeffamine D2000", active hydrogen equivalent: 514g / eq (others) Modifier for thermosetting resin (M1) Amino-terminated butadiene-acrylonitrile copolymer, Huntsman product name "Hypro 1300X16 ATBN", active hydrogen equivalent: 800-1000g / eq

[0100] <Carrier Sheet (B)> Career sheet (1) Mitsubishi Chemical Corporation, product name "MRF75", release-coated PET film, thickness 75 μm; carrier sheet including polyester film and release layer Career sheets (2) LDPE / PET film (a two-layer film made by laminating a 50 μm thick low-density polyethylene (LDPE) film with a 50 μm thick biaxially oriented polyethylene terephthalate film)

[0101] (Examples 1 to 4, Comparative Examples 1 and 2) A resin composition was prepared by blending an epoxy resin, a curing agent, and a modifier for thermosetting resins as shown in Table 1. This epoxy resin composition was applied to the release layer of a first carrier sheet (B), and a second carrier sheet (B) was laminated using two heated rolls with the clearance adjusted to the desired thickness. The resulting sample was subjected to a primary heat treatment at 40°C for 16 hours, followed by a secondary heat treatment at 80°C for 6 hours to produce a laminate. The results of various analyses and evaluations of the resin sheet (A), carrier sheet (B), and laminate are shown in Tables 1 and 2.

[0102] Example 5 A laminate was produced in the same manner as in Example 1, except that the thickness of the laminate was changed to the value shown in Table 1. The results of various analyses and evaluations of the resin sheet (A), carrier sheet (B), and laminate are shown in Tables 1 and 2.

[0103] Example 6 A laminate was produced in the same manner as in Example 2, except that the thickness of the laminate was changed to the value shown in Table 1. The results of various analyses and evaluations of the resin sheet (A), carrier sheet (B), and laminate are shown in Tables 1 and 2.

[0104] (Comparative Example 3) The resin sheet (A) was replaced with a polyurethane elastomer laminate sheet (product name "Silklon SES85-NW / PP" manufactured by Okura Kogyo Co., Ltd.) and similarly analyzed and evaluated. The results are shown in Tables 1 and 2.

[0105] [Table 1]

[0106] [Table 2]

[0107] The resin sheets (A) of Examples 1 to 6, which had at least one maximum value of tan δ in the range of -100°C to 10°C, exhibited excellent stretchability even in low-temperature environments. Furthermore, the resin sheets (A) of Examples 1 to 6 were found to have excellent impact resistance over a wide temperature range, since the tan δ of the resin sheets (A) was 0.03 or more over a wide temperature range. Furthermore, the laminates of Examples 1 to 6 had a tensile elongation of the resin sheets (A) of 50% or more, and were also excellent in adhesion to prepreg and printability. Since the resin sheet (A) can be easily obtained by peeling off the carrier sheet (B) from the laminates of Examples 1 to 6, it is expected that the laminates will be used in a variety of applications such as sporting goods.

Claims

1. A laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one surface of the epoxy resin sheet (A), The epoxy resin sheet (A) is made of a cured product obtained by curing an epoxy resin composition, and the epoxy resin composition contains at least an epoxy resin and a curing agent, The epoxy resin contains an epoxy resin having a block structure of a rigid component and a flexible component, and / or an epoxy resin having a rubber component, the curing agent is a polyetheramine and / or an amine containing an alicyclic structure, the epoxy resin sheet (A) has at least one maximum loss tangent (tanδ) in the range of −100° C. to 10° C. as determined by dynamic viscoelastic measurement in a tensile mode at a frequency of 1 Hz; the tensile elongation of the epoxy resin sheet (A) is 50% or more, The epoxy resin sheet (A) has a loss tangent (tanδ) of 0.03 or more at -40°C to 40°C as determined by dynamic viscoelasticity measurement in a tensile mode at a frequency of 1 Hz.

2. A laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one surface of the epoxy resin sheet (A), The epoxy resin sheet (A) is made of a cured product obtained by curing an epoxy resin composition, and the epoxy resin composition contains at least an epoxy resin and a curing agent, The epoxy resin contains an epoxy resin having a block structure of a rigid component and a flexible component, and / or an epoxy resin having a rubber component, the curing agent is a polyetheramine and / or an amine containing an alicyclic structure, the epoxy resin sheet (A) has at least one maximum loss tangent (tanδ) in the range of −100° C. to 10° C. as determined by dynamic viscoelastic measurement in a tensile mode at a frequency of 1 Hz; the tensile elongation of the epoxy resin sheet (A) is 50% or more, The epoxy resin sheet (A) has a tensile storage modulus of 5.0×10 at −20 to 100° C. ５ ~1.0 x 10 ９ Pa.

3. A laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one surface of the epoxy resin sheet (A), The epoxy resin sheet (A) is made of a cured product obtained by curing an epoxy resin composition, and the epoxy resin composition contains at least an epoxy resin and a curing agent, The epoxy resin contains an epoxy resin having a block structure of a rigid component and a flexible component, and / or an epoxy resin having a rubber component, the curing agent is a polyetheramine and / or an amine containing an alicyclic structure, the epoxy resin sheet (A) has at least one maximum loss tangent (tanδ) in the range of −100° C. to 10° C. as determined by dynamic viscoelastic measurement in a tensile mode at a frequency of 1 Hz; the tensile elongation of the epoxy resin sheet (A) is 50% or more, The tensile storage modulus of the laminate at 20 to 100°C is 6.0 × 10 ７ ~5.0 x 10 １０ Pa.

4. A laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one surface of the epoxy resin sheet (A), the epoxy resin sheet (A) has at least one maximum loss tangent (tanδ) in the range of −100° C. to 10° C. as determined by dynamic viscoelastic measurement in a tensile mode at a frequency of 1 Hz; the tensile elongation of the epoxy resin sheet (A) is 50% or more, The epoxy resin sheet (A) is made of a cured product obtained by curing an epoxy resin composition, and the epoxy resin composition contains at least an epoxy resin and a curing agent, the epoxy resin constituting the epoxy resin sheet (A) is an epoxy resin containing a rubber component, The laminate, wherein the curing agent is a polyetheramine and / or an amine containing an alicyclic structure.

5. The laminate according to any one of claims 1 to 4, wherein the maximum value of loss tangent (tanδ) in the range of -100°C to 10°C obtained by dynamic viscoelastic measurement of the epoxy resin sheet (A) in a tensile mode at a frequency of 1 Hz is 0.10 or more.

6. The laminate according to any one of claims 1 to 5, wherein the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) is 5 N / 15 mm width or less.

7. The laminate according to any one of claims 1 to 6, wherein the carrier sheet (B) comprises a polyester film.

8. The laminate according to any one of claims 1 to 7, wherein the carrier sheet (B) comprises a release layer.

9. The laminate according to any one of claims 1 to 8, wherein the epoxy resin sheet (A) has a thickness of 10 to 500 µm.

10. The laminate according to any one of claims 1 to 9, wherein the carrier sheet (B) is provided on both sides of the epoxy resin sheet (A).

11. A laminate according to claim 10, wherein the carrier sheet (B) is peeled off from one side of the laminate.

12. A flexible or stretchable laminate using the epoxy resin sheet (A) of the laminate according to any one of claims 1 to 11.

13. A fiber-reinforced composite material comprising the epoxy resin sheet (A) of the laminate according to any one of claims 1 to 11.

14. 14. A mobile object such as an aircraft, an automobile, a ship, or a railroad vehicle, a sporting good, a home electric appliance, or a building material, which is made using the fiber-reinforced composite material according to claim 13.

15. A method for producing an epoxy resin sheet, comprising a step of obtaining the epoxy resin sheet (A) by peeling off the carrier sheet (B) from the laminate according to any one of claims 1 to 11.

Images