JP2023032668A - Epoxy resin sheet, laminate, stretchable member, flexible member and wound body - Google Patents

Abstract

An epoxy resin sheet having resilience after being stretched is provided. The epoxy resin sheet has a hysteresis loss of 40% or less after maintaining 50% elongation for 2 seconds in tensile mode, measured according to JIS K 7312:1996. [Selection figure] None

Description

TECHNICAL FIELD The present invention relates to a sheet containing an epoxy resin as a main component resin (referred to as an "epoxy resin sheet"), and a laminate and a wound body comprising the sheet.

Epoxy resins are used in various fields due to their excellent heat resistance, adhesiveness, water resistance, mechanical strength, electrical properties, and the like. In particular, in the electric and electronic fields, with the recent miniaturization, precision, and high performance of electric and electronic parts, the epoxy resins used have come to be required to have a high degree of moldability. In addition, recently, the use of epoxy resins in applications where flexibility is emphasized, such as flexible laminates and stretchable laminates, is also being developed.

For example, Patent Document 1 discloses a specific highly flexible epoxy resin, and a resin composition containing the epoxy resin has a good balance of adhesiveness and electrical properties, while also having high flexibility. It says to give something.

In Patent Document 2, a resin composition that is flexible and has excellent resilience and stress relaxation properties after stretching includes at least (A) a polyrotaxane, (B) an epoxy resin, and (C) a curing agent, and (B) A resin composition is disclosed in which the ratio of the epoxy resin is 30 to 50 parts by mass, with the total of (A) polyrotaxane, (B) epoxy resin and (C) curing agent being 100 parts by mass. .

In Patent Document 3, as a laminate capable of suppressing problems such as elongation, deflection, and wrinkling of an epoxy resin sheet during secondary processing, an epoxy resin having a block structure of a rigid component and a flexible component, and an epoxy resin are disclosed. A laminate comprising the present epoxy resin sheet made of a cured product obtained by curing an epoxy resin composition containing a cyclic polyamine and a carrier sheet on at least one side of the present epoxy resin sheet,
The present epoxy resin sheet has a tensile storage modulus at 100° C. to 200° C. of 1.0×10 ⁴ to 6.0×10 ⁷ Pa and a tensile elongation of 150% or more,
A laminate having a tensile storage modulus of 6.0×10 ⁷ to 1.0×10 ¹⁰ Pa at 100° C. to 200° C. of the laminate is disclosed.

JP 2005-320477 A JP 2018-172697 A WO2020/027291

2. Description of the Related Art Conventionally, cushioning materials mainly composed of urethane resins and silicone resins have been used in semiconductor manufacturing processes and the like. As mentioned above, epoxy resin is excellent in heat resistance, adhesiveness, mechanical strength and electrical properties. You can expect to be able to.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an epoxy resin sheet having resilience after stretching, and a laminate and a wound body using the epoxy resin sheet.

The present invention proposes an epoxy resin sheet having a hysteresis loss of 40% or less after maintaining 50% elongation for 2 seconds in tensile mode, measured according to JIS K 7312:1996.

The invention also proposes a laminate comprising a carrier sheet on at least one side of said epoxy resin sheet.

The present invention also provides a wound body in which a laminate comprising an epoxy resin sheet and a carrier sheet on at least one side of the epoxy resin sheet is wound around a core,
A wound body having a hysteresis loss of 40% or less after maintaining 50% elongation for 2 seconds in a tension mode of the epoxy resin sheet measured according to JIS K 7312:1996 is proposed.

The epoxy resin sheet proposed by the present invention has resilience after being stretched. In addition, as described above, epoxy resins have excellent properties such as heat resistance, adhesiveness, mechanical strength and electrical properties. Since it can be used repeatedly as a member used in such as a mold release material, a cushioning material, an anti-slip material, etc., it can be expected to be effectively used in new applications.

FIG. 1 is a diagram showing a conceptual diagram of a stress-strain curve used when obtaining hysteresis loss and a relational expression for obtaining hysteresis loss.

Next, the present invention will be described based on embodiments. However, the present invention is not limited to the embodiments described below.

<This epoxy resin sheet>
An epoxy resin sheet (referred to as "present epoxy resin sheet") according to an example of the embodiment of the present invention is a sheet formed from an epoxy resin composition containing an epoxy resin as a main component resin.

In this specification, the term "epoxy resin" refers to both raw material resin before curing and resin after curing (cured product). Since epoxy groups are consumed by the curing reaction, the cured resin may not have epoxy groups (epoxy structures), but these are not distinguished in this specification.

(Hysteresis loss)
The present epoxy resin sheet preferably has a hysteresis loss of 40% or less after maintaining 50% elongation in tensile mode for 2 seconds, measured according to JIS K 7312:1996, especially 30% or less. It is more preferably 25% or less. Although the lower limit of the hysteresis loss is not particularly limited, it is usually 3% or more.
If the hysteresis loss of the present epoxy resin sheet is within the above range, it is excellent in resilience after elongation. Therefore, it is preferable.
The hysteresis loss of the present epoxy resin sheet is specifically measured by the method described in Examples.

(Tensile storage modulus)
The tensile storage modulus of the present epoxy resin sheet at 100° C. to 200° C. is preferably 1.0×10 ⁴ Pa to 6.0×10 ⁷ Pa, especially 6.0×10 ⁴ Pa or more or 1.0×10 4 Pa or more. 0×10 ⁷ Pa or less, more preferably 4.0×10 ⁵ Pa or more or 9.0×10 ⁶ Pa or less.
Here, "the tensile storage modulus at 100°C to 200°C is 1.0 × 10 ⁴ to 6.0 × 10 ⁷ Pa" means that the tensile storage modulus is 1 in the entire temperature range from 100°C to 200°C. It means maintaining a value of 0×10 ⁴ or more and 6.0×10 ⁷ Pa or less.
If the tensile storage modulus of the present epoxy resin sheet is within the above range, the sheet is more excellent in stretchability than ordinary epoxy resin sheets, which is preferable.
The tensile storage modulus of the present epoxy resin sheet can be specifically measured by the method described in Examples.

(Peel strength)
The peel strength between the epoxy resin sheets is preferably 0.05 N/15 mm to 2.5 N/15 mm, especially 0.1 N/15 mm or more or 2 N/15 mm or less, especially 0.2 N/15 mm or more or 1 0.5 N/15 mm or less, more preferably 0.3 N/15 mm or more or 1 N/15 mm or less.
When the tensile storage elastic modulus of the epoxy resin sheets is within the above range, the epoxy resin sheet has appropriate tackiness when used as a release material, cushioning material, anti-slip material, and the like. While the anti-slip effect of the member can be expected, the epoxy resin sheet can be easily peeled off from the member, and there is no risk that the epoxy resin sheet will stretch, resulting in repeated use of the epoxy resin sheet. easier to do.
The peel strength between the epoxy resin sheets can be specifically measured by the method described in Examples.

(Glass-transition temperature)
The present epoxy resin sheet preferably has a glass transition temperature of 20° C. or lower.
Since the glass transition temperature of a general epoxy resin sheet is about 110 to 130° C., if the glass transition temperature of the present epoxy resin sheet is 20° C. or less, the glass transition temperature is significantly higher than that of a general epoxy resin sheet. can be said to be low. An epoxy resin sheet having a glass transition temperature of 20° C. or less is preferable from the viewpoint of softness and flexibility.
From the viewpoint that the flexible material can be used in a wider temperature range, the glass transition temperature of the present epoxy resin sheet is preferably 20° C. or lower, more preferably 15° C. or lower, and more preferably 10° C. or lower.
However, if the glass transition temperature is too low, the handling of the film may be deteriorated, such as wrinkles being generated with a small force or the film being cut. The glass transition temperature is preferably −40° C. or higher, more preferably −30° C. or higher, more preferably −25° C. or higher.
The glass transition temperature of the present epoxy resin sheet can be adjusted, for example, by the types and content ratios of the epoxy resin (α) and the aliphatic epoxy resin (β), which will be described later. From this point of view, the epoxy resin (α) and the aliphatic epoxy resin (β) are compatible with each other, one glass transition temperature appears, and the glass transition temperature can be lowered by the aliphatic epoxy resin (β). is preferred.
The glass transition temperature of the epoxy resin sheet can be specifically measured by the method described in Examples.

(thickness)
The average thickness of the epoxy resin sheet is preferably 10 μm to 500 μm from the viewpoint of production and practical use, especially 20 μm or more or 200 μm or less, especially 30 μm or more or 150 μm or less, especially 50 μm or more or 140 μm or less. More preferably:
The average thickness of the present epoxy resin sheet can be obtained by measuring the thickness at at least three points with a micrometer and calculating the arithmetic mean thereof.

(Epoxy resin composition (a))
The present epoxy resin sheet is preferably a resin composition containing an epoxy resin as a main component resin, a curing agent, and optionally other components (hereinafter referred to as an "epoxy resin composition ( A) is a sheet-like molded body made of a cured product obtained by curing a).

The "main component resin" means a resin having the highest mass ratio among the resin components constituting the epoxy resin composition (a). % or more, 60 mass % or more, 70 mass % or more, 80 mass % or more, 90 mass % or more, or 100 mass %.
Moreover, "curing" means intentionally curing the epoxy resin composition (a) with heat and/or light. Here, the term "intentionally" includes, for example, cases in which the present epoxy resin sheet before curing is stored for a long period of time and is gradually cured under the influence of heat or light over time.

(Epoxy resin)
The epoxy resin of the epoxy resin composition (a) preferably contains an epoxy resin (α) having a block structure of a rigid component and a flexible component and an aliphatic epoxy resin (β).
When the epoxy resin sheet contains the epoxy resin (α) in combination with the aliphatic epoxy resin (β), the hysteresis loss of the epoxy resin sheet can be reduced.
As described above, from the viewpoint of adjusting the glass transition temperature of the present epoxy resin sheet, the epoxy resin (α) and the aliphatic epoxy resin (β) are compatible with each other, one glass transition temperature appears, and the aliphatic epoxy resin (β) Those whose glass transition temperature can be lowered by the epoxy resin (β) are preferred.

[Epoxy resin (α)]
Epoxy resin (α) is an epoxy resin having a block structure of a rigid component and a flexible component.
By including such an epoxy resin (α), it becomes possible to impart flexibility to the cured product.

The rigid component has an aromatic ring structure, such as a condensed aromatic ring structure such as a benzene ring, naphthalene ring, anthracene ring, or pyrene ring, or a structure containing many 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.

On the other hand, the flexible component preferably contains an aliphatic hydrocarbon such as an alkylene group having 1 to 8 carbon atoms, an ethylene glycol group, a propylene glycol group and a butylene glycol group.

The epoxy resin (α) does not necessarily have to have an epoxy group or a structure derived from an epoxy group in both the rigid component and the flexible component. That is, at least one of the rigid component and the flexible component should have an epoxy group or a structure derived from an epoxy group. From the viewpoint of imparting flexibility while maintaining the inherent properties of epoxy resins such as heat resistance and mechanical strength, only one of the rigid component and the flexible component has an epoxy group or a structure derived from an epoxy group. preferably.

Specific examples of the epoxy resin (α) include bisphenol F units (simply referred to as “bisphenol F”; the same applies to others) and alkyldiol diglycidyl ether units (simply referred to as “alkyldiol diglycidyl ether”; the same applies to others). Epoxy resins containing, for example, bisphenol F units (simply referred to as "bisphenol F"; the same applies to others) and 1,6-hexanediol diglycidyl ether units (simply referred to as "1,6-hexanediol diglycidyl ether"). and others), a copolymer of 1,6-hexanediol and bisphenol F diglycidyl ether, a copolymer of bisphenol F and 1,4-butanediol diglycidyl ether, 1,4- copolymers of butanediol and bisphenol F diglycidyl ether, copolymers of bisphenol A and 1,6-hexanediol diglycidyl ether, copolymers of 1,6-hexanediol and bisphenol A diglycidyl ether, A copolymer of bisphenol A and 1,4-butanediol diglycidyl ether, a copolymer of 1,4-butanediol and bisphenol A diglycidyl ether, tetramethylbiphenol and 1,6-hexanediol diglycidyl ether a copolymer of 1,6-hexanediol and tetramethylbiphenol diglycidyl ether, a copolymer of tetramethylbiphenol and 1,4-butanediol diglycidyl ether, 1,4-butanediol and Copolymers of tetramethylbiphenol diglycidyl ether, copolymers of biphenol and 1,6-hexanediol diglycidyl ether, copolymers of 1,6-hexanediol and biphenol diglycidyl ether, biphenol and 1,6-hexanediol diglycidyl ether Copolymers of 4-butanediol diglycidyl ether, copolymers of 1,4-butanediol and biphenol diglycidyl ether, copolymers of 1,4-naphthalenediol and 1,6-hexanediol diglycidyl ether Copolymer, copolymer of 1,6-hexanediol and 1,4-naphthalenediol diglycidyl ether, copolymer of 1,4-naphthalenediol and 1,4-butanediol diglycidyl ether, 1,4- Copolymers of butanediol and 1,4-naphthalenediol diglycidyl ether, copolymers of 1,6-naphthalenediol and 1,6-hexanediol diglycidyl ether polymer, copolymer of 1,6-hexanediol and 1,6-naphthalenediol diglycidyl ether, copolymer of 1,6-naphthalenediol and 1,4-butanediol diglycidyl ether, 1,4 A copolymer of -butanediol and 1,6-naphthalenediol diglycidyl ether can be mentioned.
In addition, the epoxy equivalent of the epoxy resin (α) is preferably 300 to 5000 g/equivalent from the viewpoint of maintaining the flexibility of the epoxy cured product, and more preferably 500 g/equivalent or more or 2000 g/equivalent or less. preferable.
One of these may be used alone, or two or more of them may be used in any combination and ratio.
Among these, from the viewpoint of flexibility, the epoxy resin (α) is a copolymer of bisphenol F and alkyldiol diglycidyl ether, especially a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether. is preferred.

[Aliphatic epoxy resin (β)]
Aliphatic epoxy resin (β) is an epoxy resin having a non-aromatic carbon chain, the carbon chain may be acyclic or cyclic, linear or branched. and the bond may be saturated or unsaturated. Moreover, the number of functional groups may be monofunctional or polyfunctional (bifunctional or more).
The present epoxy resin sheet formed from an epoxy resin composition containing an aliphatic epoxy resin (β) that is softer than the aliphatic epoxy resin (α), which is a relatively hard component, has a small hysteresis loss and excellent resilience. become a thing. Furthermore, this sheet has moderate tackiness. Therefore, while the anti-slip effect of the member arranged on the surface of the epoxy resin sheet can be expected, the epoxy resin sheet can be easily peeled off from the member, and the epoxy resin sheet can be used repeatedly. can be expected.

As aliphatic epoxy resins (β), mention may be made of epoxy resins formed by glycidyls of aliphatic alcohols or polyols. For example, monoglycidyl etherified products of aliphatic alcohols, monoepoxy compounds such as glycidyl esters of alkylcarboxylic acids, polyglycidyl etherified products of aliphatic polyhydric alcohols or their alkylene oxide adducts, polyglycidyl of aliphatic long-chain polybasic acids Examples include polyfunctional epoxy compounds such as esters.

Specific examples of monomer components constituting the aliphatic epoxy resin (β) include allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and C11-13 mixed alkyl glycidyl ether (wherein the alkyl group has 11-13 carbon atoms). mixture of alkyl glycidyl ethers), 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, tetraglycidyl ether of sorbitol, hexaglycidyl ether of dipentaerythritol, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, Polyether polyols obtained by adding one or more alkylene oxides to glycidyl ethers of polyhydric alcohols such as polyglycerin polyglycidyl ether, or aliphatic polyhydric alcohols such as propylene glycol, trimethylolpropane and glycerin and diglycidyl esters of aliphatic long-chain dibasic acids. Furthermore, monoglycidyl ethers of higher aliphatic alcohols, glycidyl esters of higher fatty acids, epoxidized soybean oil, octyl epoxystearate, butyl epoxystearate, epoxidized soybean oil, and epoxidized polybutadiene can be used.
The aliphatic epoxy resin (β) may be used alone or in combination of two or more.

Among them, the aliphatic epoxy resin (β) is preferably an epoxy resin having an aliphatic ether unit from the viewpoint of further improving the restorability of the present epoxy resin sheet. Among them, an epoxy resin obtained from polyether glycol is preferred.

As the "epoxy resin obtained from polyether glycol", one or more of glycols such as ethylene glycol, propylene glycol, tetramethylene ether glycol, neopentyl glycol, etc., and/or epichlorohydrin as a reaction product. Epoxy resins may be mentioned. In addition, the epoxy equivalent of the polyether glycol is preferably 100 to 2000 g/equivalent, more preferably 250 g/equivalent or more or 1500 g/equivalent or less, from the viewpoint of maintaining the flexibility of the epoxy cured product. .
Epoxy resins obtained from polyether glycol may be used singly or in combination of two or more.

Among them, aliphatic polyglycidyl ethers are preferable as the aliphatic epoxy resin (β) from the viewpoint of further enhancing the restorability of the present epoxy resin sheet.
Examples of aliphatic polyglycidyl ethers include polyglycidyl ethers such as ethylene glycols, propylene glycols, tetramethylene glycols, and sorbitol polyglycidyl ethers.
Specific product examples include polyalkylene glycol diglycidyl ethers such as polytetramethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and alkyl glycidyl ethers.
It is considered that these aliphatic polyglycidyl ethers are compatible with the epoxy resin (α) when mixed in combination with the epoxy resin (α), thereby further enhancing the restorability of the present epoxy resin sheet.

Regarding the content ratio of the aliphatic epoxy resin (β), it is preferable to increase the content of the aliphatic epoxy resin (β) from the viewpoint of improving the resilience, but the ratio of the aliphatic epoxy resin (β) is high. If too much, it becomes difficult to maintain the strength. From this point of view, the aliphatic epoxy resin (α) and the aliphatic epoxy resin (β) account for the total solid content in the epoxy resin composition (a) The epoxy resin (β) is preferably 5 to 80% by mass, especially 5% by mass or more or 50% by mass or less, among them 10% by mass or more or 40% by mass or less, among them 15% by mass or more or 35% by mass More preferably:
Here, the "solid content" means a component excluding the solvent, and includes not only solid epoxy resins or epoxy compounds, but also semi-solid and viscous liquid substances.

[Filling material]
The epoxy resin composition (a) can contain a filler (also referred to as "filler"), if necessary.
By adding a filler to the epoxy resin composition (a), the viscosity of the epoxy resin composition (a) is increased, making it easier to handle, and the strength of the present epoxy resin sheet can be increased. For example, for the purpose of improving various properties such as the effect of lowering the curing shrinkage of the resulting cured product and the effect of lowering the coefficient of thermal expansion, the epoxy resin composition (a) is blended with an inorganic filler to provide an electrical・It is possible to develop applications in the field of electronics, especially liquid semiconductor encapsulants. It is also conceivable to include organic fillers such as rubber particles, acrylic particles, etc. to impart toughness.

Examples of the filler include powdery reinforcing materials and fillers, for example, metal oxides such as aluminum oxide and magnesium oxide, metal carbonates such as calcium carbonate and magnesium carbonate, diatomaceous earth powder, basic magnesium silicate, Calcined clay, fine powder silica, fused silica, silicon compounds such as zeolite, metal hydroxides such as aluminum hydroxide, kaolin, mica, quartz powder, graphite, carbon black, carbon nanotubes, molybdenum disulfide, boron nitride, Aluminum nitride etc. can be mentioned.

Moreover, it is also possible to mix|blend a fibrous reinforcing material and a filler as a filler.
Examples of fibrous reinforcing materials and fillers include glass fibers, ceramic fibers, carbon fibers, alumina fibers, silicon carbide fibers, boron fibers, aramid fibers, cellulose nanofibers, and cellulose nanocrystals. Cloth or non-woven fabric of organic fibers or inorganic fibers can also be used.

The above-mentioned filler may be surface-treated with a silane coupling agent, titanate-based coupling agent, aluminate-based coupling agent, or the like, or may be primer-treated.

When a filler is added, it is preferable to ensure the tensile storage modulus of the present epoxy resin sheet within the above range. From this point of view, the content of these fillers is 100 parts by mass of the sum of the amount of epoxy resin (total of epoxy resin (α) and aliphatic epoxy resin (β), hereinafter the same) and the amount of curing agent 0.1 to 900 parts by mass, preferably 1 to 500 parts by mass, more preferably 3 to 100 parts by mass.

[Hardener]
The curing agent of the epoxy resin composition (a) is at least a group reactive with the epoxy group of the epoxy resin (α) to the aliphatic epoxy resin (β), in other words, a substance that contributes to the cross-linking reaction between the cross-linking groups. is preferred.
As such a curing agent, one generally known as an epoxy resin curing agent can be used. For example, phenolic curing agents, aliphatic amines, polyether amines, alicyclic amines, amine curing agents such as aromatic amines, acid anhydride curing agents, amide curing agents, tertiary amines, imidazoles and their Derivatives, organic phosphines, phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, halogenated boron amine complexes, polymercaptan curing agents, isocyanate curing agents, blocked isocyanate curing agents and the like can be mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type.
Among them, a curing agent having an alicyclic structure is preferable as the curing agent from the viewpoint of high transparency and little coloration.

The curing agent having an alicyclic structure is preferably a substance that has an alicyclic structure and contributes to the cross-linking reaction and/or chain extension reaction between epoxy groups of the epoxy resin. Examples include alicyclic polyamines and alicyclic acid anhydrides. More specifically, 1,4-diazabicyclo-2,2,2-octane, 1,8-diazabicyclo-5,4,0-undec-7-ene, N,N'-dimethylpiperazine, N-aminoethylpiperazine . can be epoxy-modified, ethylene oxide-modified, dimer acid-modified, Mannich-modified, Michael addition, thiourea condensation, ketiminated modified alicyclic polyamine, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and the like. These may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these, alicyclic polyamines are preferred, and isophoronediamine, hexamethylenetetramine, methylenebiscyclohexanamine, 1,3-bisaminomethylcyclohexane, norbornenediamine, 1,2-diaminocyclohexane, and modified products thereof are preferred. Especially preferred.
From the viewpoint of maintaining the flexibility of the cured epoxy product, the active hydrogen equivalent of the curing agent is preferably 10 to 500 g/equivalent, more preferably 50 g/equivalent or more or 250 g/equivalent or less.

A commercially available curing agent having an alicyclic structure can also be used, for example, Mitsubishi Chemical Co., Ltd. "jER Cure 113", "jER Cure ST-14", New Japan Chemical Co., Ltd. "Rikashid MH-700" etc. can be used.

Amount of curing agent in the epoxy resin composition (a) (when using a curing agent other than a curing agent having an alicyclic structure, the total content of the curing agent having an alicyclic structure and the other curing agent , hereinafter the same) is preferably 0.1 to 100 parts by mass per 100 parts by mass of the epoxy resin (the total amount of the epoxy resin (α) and the aliphatic epoxy resin (β)), especially 1 mass parts or more and 80 parts by mass or less, more preferably 5 parts by mass or more and 60 parts by mass or less, more preferably 8 parts by mass or more and 40 parts by mass or less.

[solvent]
If necessary, the epoxy resin composition (a) may be diluted with a solvent in order to appropriately adjust the viscosity of the epoxy resin composition (a) during handling such as coating film formation. .
In the epoxy resin composition (a), the solvent is used to ensure handleability and workability when preparing the epoxy resin composition (a), and the amount used is not particularly limited.
In the present invention, the terms "solvent" and "solvent" are used separately depending on the mode of use, but the same type or different types may be used independently.

Solvents that the epoxy resin composition (a) may contain include, for example, acetone, methyl ethyl ketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate, ethylene glycol monomethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, Methanol, ethanol and the like can be mentioned, and these solvents can be used as a mixed solvent of two or more as appropriate.

[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 (a).
Specifically, the epoxy resin composition (a) optionally contains a coupling agent, a plasticizer, a diluent, a flexibility imparting agent, a dispersant, a wetting agent, a coloring agent, a pigment, and an ultraviolet absorber. , a light stabilizer such as a hindered amine light stabilizer, an antioxidant, a defoaming agent, a release agent, a flow control agent, and the like.
The content of these is preferably 20 parts by mass or less per 100 parts by mass of the sum of the epoxy resin amount (the total amount of the epoxy resin (α) and the aliphatic epoxy resin (β)) and the curing agent. On the other hand, the lower limit is not particularly limited, but 0.1 parts by mass or more is preferable.

Furthermore, for the purpose of improving the properties of the resin in the final coating film, the epoxy resin composition (a) may optionally contain various curable monomers, oligomers and synthetic resins.
For example, one or a combination of two or more of cyanate ester resins, acrylic resins, silicone resins, urethane resins, polyester resins, and the like can be used.
The content of these resins is an amount within a range that does not impair the original properties of the epoxy resin composition (a), that is, the amount of epoxy resin (total amount of epoxy resin (α) and aliphatic epoxy resin (β)) and 50 parts by mass or less is preferable with respect to 100 parts by mass of the total amount of the curing agent. On the other hand, the lower limit is not particularly limited, but 1.0 parts by mass or more is preferable.

(Manufacturing method of this epoxy resin sheet)
The present epoxy resin sheet can be produced by molding the epoxy resin composition (a) into a sheet having a predetermined thickness and then curing the composition. Alternatively, it can be produced by molding a semi-cured product obtained from the epoxy resin composition (a) into a sheet having a predetermined thickness and further curing the same.

The curing method of the epoxy resin composition (a) varies depending on the components and amounts contained in the epoxy resin composition (a), and the shape of the components (for example, the thickness of the sheet). A method of heating under heating conditions of 5 minutes to 24 hours can be mentioned.
This heating is a two-stage treatment of primary heating at 23 to 160° C. for 5 minutes to 24 hours and secondary heating at 80 to 200° C., which is 40 to 177° C. higher than the primary heating temperature, for 5 minutes to 24 hours. is preferable from the viewpoint of reducing poor curing. Furthermore, if a three-stage treatment is performed in which tertiary heating is performed at 100 to 200° C., which is higher than the secondary heating temperature, for 5 minutes to 24 hours, it can be expected to reduce poor curing.

The epoxy resin sheet may be in a semi-cured state. If the present epoxy resin sheet is in a semi-cured state, it may be easily formed into a wound body, or the secondary workability may be improved.
When the present epoxy resin sheet is produced as a semi-cured product, the curing reaction of the epoxy resin composition (a) may be advanced by heating or the like to such an extent that the shape can be maintained. When the epoxy resin composition (a) contains a solvent, most of the solvent is removed by heating, pressure reduction, air drying, or the like, leaving 5% by mass or less of the solvent in the semi-cured product. good too.

(Application of this epoxy resin sheet)
Since this epoxy resin sheet has resilience, it is suitably used as a release material, cushioning material, non-slip material (sealing material), etc. in the manufacturing process of various molded products, especially press molding, vacuum molding, pressure molding, etc. be able to.
In addition, including fields other than electronic and electrical material applications, various industrial cushioning materials, adhesive sheets, adhesive sheets, elastic tapes, sealing sheets, heat-resistant insulating sheets, heat-resistant conductive sheets, glass substitutes, protective films, It can also be suitably used as a medical sheet, an agricultural sheet, a construction sheet, and the like.

In addition, the present epoxy resin sheet can also be used as a flexible plate or stretchable plate in which flexibility is emphasized. Examples of flexible boards or stretchable boards include printed wiring boards in which metal foil such as copper foil is laminated. In other words, the epoxy resin sheet can be used as a flexible member or stretchable member.
As a method for producing the printed wiring board, for example, copper foil is laminated on one or both sides of the present epoxy resin sheet, hot press molding is performed using a vacuum press machine or the like to produce a copper clad laminate, and etching is performed. A method of forming a wiring pattern and obtaining a printed wiring board can be exemplified. Moreover, the printed wiring board etc. which used the electrically conductive paste are mentioned as a wiring pattern.

One or both sides of the present epoxy resin sheet may be coated with a conductive paste by a known method such as screen printing or inkjet printing to form a wiring pattern, thereby obtaining a printed wiring board. . The conductive paste preferably has flexibility and stretchability.
A flexible device or a stretchable device can be obtained by mounting various electronic elements on the printed wiring board.

<Main laminate>
A laminate (referred to as "this laminate") according to an example of the embodiment of the present invention is a laminate comprising a carrier sheet on at least one side of the present epoxy resin sheet.

(Carrier sheet)
By laminating the carrier sheet, the strength of the present laminate is increased, and not only is it easier to handle, but it can also be used repeatedly. Moreover, even if the present epoxy resin sheet is viscous, the surface of the carrier sheet is not viscous, so it can be prevented from adhering to machines and delaying the process.

The carrier sheet may be provided on one side or both sides of the epoxy resin sheet.
When carrier sheets are provided on both sides of the present epoxy resin sheet, they may be made of the same material and thickness, or may be made of different materials and thicknesses.

The average thickness of the carrier sheet is preferably 1 to 500 μm, more preferably 5 μm or more and 300 μm or less, more preferably 10 μm or more and 150 μm or less, and more preferably 20 μm or more and 120 μm or less.
The average thickness of the carrier sheet is obtained by measuring the thickness at at least three points with a micrometer and calculating their arithmetic mean.

As the carrier sheet, a thin sheet made of paper, resin, metal, or the like can be used. In particular, paper and resin films are preferred from the viewpoints of being inexpensive, easy to process, and easy to discard or recycle, and resin films are more preferred from the viewpoint of transparency.

Examples of paper that can be used include woodfree paper, kraft paper, glassine paper, parchment paper, supercalendered kraft paper, and the like, the surface of which is coated with silicone.

Examples of resin films that can be used include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polyethylene naphthalate, films mainly composed of polyimide or polycarbonate, and metal foils such as copper foil. A silicone resin release agent or the like may be applied to these surfaces to adjust the peel strength.
Metal foils such as copper foils can be given as examples of thin sheet-like materials made of metal or the like.

From the viewpoint of appearance, the carrier sheet is preferably a resin film containing polyester as a main component resin, a resin film containing polyimide as a main component resin, or a copper foil.
The "main component resin" means a resin having the highest content among the resins constituting the carrier sheet, specifically 50% by mass or more, especially 70% by mass or more, and especially 80% by mass or more. , a resin that accounts for 90% by mass or more (including 100% by mass) of them.

The polyester is preferably obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. The polyester may be a polyester composed of one aromatic dicarboxylic acid and one aliphatic glycol, or may be a copolyester further copolymerized with one or more other components.
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, 1,4-cyclohexanedimethanol, and the like. .
On the other hand, 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 glycol components include ethylene glycol, diethylene glycol, Propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like can be mentioned. Oxycarboxylic acids such as p-oxybenzoic acid can also be used.

Typical 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. can.

The polyimide may be obtained by polymerizing a tetracarboxylic acid or an aromatic tetracarboxylic anhydride and a diamine. or obtained by polymerizing with an aliphatic diamine.

The resin film may be a non-stretched film or a stretched film, but is preferably a stretched film from the viewpoint of mechanical strength, and more preferably a biaxially stretched film. In addition, the resin film may be previously subjected to surface treatment such as corona treatment or plasma treatment.

The carrier sheet may have a single-layer structure or a multi-layer structure of two or more layers, as long as the gist of the present invention is not exceeded.
Further, the surface of the carrier sheet may be coated with a silicone resin release agent or the like to adjust the peel strength.

(Laminate structure)
As long as the laminate is provided with a carrier sheet on at least one side of the epoxy resin sheet, even if it is provided with "another layer" between the epoxy resin sheet and the carrier sheet, the "other layer" is provided on the surface of the carrier sheet. layer", or one side of the present epoxy resin sheet opposite to one of the carrier sheets may be provided with the "other layer".
Examples of the "other layer" include a release layer, an adhesive layer, an adhesive layer, a hard coat layer, a barrier layer, and the like.
For example, the laminate may have a carrier sheet on at least one side of the epoxy resin sheet via a release layer.

(release layer)
The release layer can be formed, for example, as the outermost layer of the carrier sheet, that is, the outermost layer on the side that contacts the epoxy resin sheet.
By further including a release layer in the carrier sheet, it becomes easy to adjust the peel strength between the present epoxy resin sheet and the carrier sheet.

Components of the release layer are not particularly limited, and may contain silicone compounds, fluorine compounds, waxes, surfactants, and the like. It is preferable to use a silicone compound from the viewpoint of a good balance between cost and releasability.
Furthermore, a release control agent may be used in combination to adjust the release property of the release layer.

For example, commercially available carrier sheets containing a polyester film and a release layer include "Purex A31" manufactured by Teijin Film Solution Co., Ltd. and "MRF-38" and "MRF" manufactured by Mitsubishi Chemical Corporation. -75” can be mentioned.

(Manufacturing method)
The method for producing the laminate is not particularly limited. For example, when explaining a method for manufacturing a laminate having carrier sheets on both sides of the present epoxy resin sheet, the following manufacturing method 1 and manufacturing method 2 can be mentioned.

As production method 1, the epoxy resin composition (a) is applied onto a first carrier sheet, the epoxy resin composition (a) is cured to form the present epoxy resin sheet, and then the present epoxy resin sheet is formed. A method of bonding a second carrier sheet to the surface opposite to the surface provided with the first carrier sheet can be mentioned.

As production method 2, the epoxy resin composition (a) is applied onto a first carrier sheet, and the surface of the epoxy resin composition (a) opposite to the surface provided with the first carrier sheet is coated with a second A method of forming the epoxy resin sheet by curing the epoxy resin composition (a) after laminating two carrier sheets can be mentioned.

The epoxy resin sheet may be obtained by peeling off the carrier sheet from the laminate. That is, as a method for producing the present epoxy resin sheet, there can be mentioned a method of obtaining the present epoxy resin sheet by peeling off the carrier sheet from the present laminate.

(Physical properties of this laminate)
The tensile storage modulus of the laminate at 100° C. to 200° C. is preferably 6.0×10 ⁷ to 1.0×10 ¹⁰ Pa.
A carrier sheet is laminated on at least one side of the present epoxy resin sheet to form a laminate, and the tensile storage modulus of the laminate at 100° C. to 200° C. is adjusted to 6.0×10 ⁷ to 1.0×10 ¹⁰ Pa. As a result, problems such as elongation, bending, and wrinkling of the epoxy resin sheet during secondary processing can be suppressed, and handleability can be improved. More specifically, by adjusting the tensile storage modulus of the laminate at 100° C. to 200° C. within the above range, even if the epoxy resin sheet is flexible, the laminate does not flex or wrinkle. Not only is the generation suppressed, but also, for example, when the laminate is punched, the laminate does not stick to the punching blade, and the punched member has good dimensional stability. In addition, if the tensile storage modulus of the laminate at 100° C. to 200° C. is equal to or less than the above upper limit, the laminate can be easily formed into a wound body (roll) shape, and in the state of the wound body Even when it is drawn out after being stored for a long period of time and subjected to secondary processing, it is possible to maintain the same shape (thickness variation, etc.) and various properties as those at the beginning of production.
From this point of view, the tensile storage modulus of the laminate at 100° C. to 200° C. is preferably 6.0×10 ⁷ to 1.0×10 ¹⁰ Pa, especially 8.0×10 ⁷ Pa or more, or 5.0×10 ⁹ Pa or less, more preferably 1.0×10 ⁸ or more or 1.0×10 ⁹ Pa or less.

It should be noted that “a tensile storage modulus of 6.0×10 ⁷ to 1.0×10 ¹⁰ Pa at 100° C. to 200° C.” means that the tensile storage modulus is 6.0×10 10 Pa in the entire temperature range of 100° C. to 200° C. It means maintaining a value of 0×10 ⁷ or more and 1.0×10 ¹⁰ Pa or less.
Specifically, the tensile storage modulus of the laminate can be measured by the method described in Examples.

In the laminate, when the carrier sheet is peeled from the epoxy resin sheet for use, the peel strength between the epoxy resin sheet and the carrier sheet is preferably 5 N/15 mm or less, especially 3 N/15 mm or less. Among them, 1 N/15 mm or less is more preferable.
When the peel strength is equal to or less than the upper limit, the epoxy resin sheet or laminate having excellent stretchability can be obtained without damaging the peeling surface of the epoxy resin sheet when the carrier sheet is peeled off from the epoxy resin sheet. can be easily obtained.

The laminated body can be configured such that the carrier sheet can be easily peeled off from the epoxy resin sheet as described above, or can be configured so that the carrier sheet is not peeled off. In the case of a structure that does not peel off, an adhesive layer may be laminated between the epoxy resin sheet and the carrier sheet.

(thickness)
The average thickness of the laminate is preferably 30 μm to 1000 μm, more preferably 50 μm or more and 500 μm or less, more preferably 80 μm or more and 400 μm or less, and more preferably 100 μm or more and 350 μm or less.
The average thickness of the laminate can be obtained by measuring the thickness at at least three points with, for example, a micrometer, and calculating the arithmetic mean thereof.

(Use of this laminate)
This laminate can be used for the same applications as the present epoxy resin sheet described above. Specifically, it can be suitably used as a release material, cushioning material, non-slip material (sealing material), etc. in the manufacturing processes of various molded bodies, particularly press molding, vacuum molding, pressure molding, and the like. In addition, the present laminate can be suitably used as a carrier film for transporting works, a protective film for protecting works, and the like.
In addition, the present laminate can also be used as a member in which flexibility is emphasized, for example, a flexible member provided with a laminate, or a stretchable member.

<Main roll>
A wound body (referred to as "the wound body") according to an embodiment of the present invention is a laminate comprising a carrier sheet on at least one side of the present epoxy resin sheet, that is, the laminated body is wound around a core. It has a configured configuration.

Epoxy resin sheets generally known in the past are too hard, and there is a possibility that defects such as wrinkles and cracks may occur when the sheet is wound. On the other hand, the present epoxy resin sheet is flexible as described above, and therefore can be suitably formed into a wound body. Furthermore, since the present laminate has a specific tensile storage elastic modulus, the handleability (defects such as elongation, deflection, and wrinkles) when the wound body is unwound and used is improved.

In the present wound body, the variation rate of the thickness of the present laminate is preferably 20% or less, more preferably 15% or less, still more preferably 10% or less, and even more preferably 5.0 % or less.
When the variation rate of the thickness of the laminate is 20% or less, the thickness of the laminate is uniform, and a wound body in which the variation of the thickness is suppressed is realized. As a result, flexible or stretchable laminates and the like can be manufactured with good productivity. It should be noted that the lower the variation rate of the thickness of the laminate, the better, and the lower limit thereof is 0% or more.

The fluctuation rate of the thickness of the laminate in the wound body is the maximum numerical value calculated by the following formula. Here, the thickness of the laminate is obtained by measuring the thickness at five locations at intervals of 2 m in the machine direction and at intervals of 10 mm in the width direction from the edge of the laminate.
Variation rate of thickness [%] = 100 × | (maximum or minimum thickness of laminate) - (average thickness of laminate) | / (average thickness of laminate)

(core)
The core is a cylindrical winding core used for winding the laminate.

Materials for the core include, for example, paper, resin-impregnated paper, acrylonitrile/butadiene/styrene copolymer (ABS resin), fiber reinforced plastic (FRP), phenolic resin, and inorganic-containing resin. An adhesive may be used for the core.
Among them, plastics, thermosetting resins, and the like are preferable as the material of the core from the viewpoints of having a small coefficient of thermal expansion, high rigidity, low swelling property against humidity, and excellent winding properties.
When the material of the core is paper, the desired properties can be easily obtained by coating the surface with a resin or the like.
From the viewpoint of surface smoothness, the core is preferably a tube of resin-impregnated paper.

The outer diameter of the core is preferably 10 mm or more and 2,000 mm or less, more preferably 15 mm or more and 1,900 mm or less, and still more preferably 20 mm or more and 1,700 mm or less. It is preferable that the outer diameter of the core is 10 mm or more because the laminate is easily affected by the quality of the core.

<Explanation of terms>
In the present invention, the term "film" also includes the "sheet", and the term "sheet" also includes the "film".

In the present invention, when described as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, "X or more and Y or less" and "preferably larger than X" or "preferably Y It also includes the meaning of "less than".
In addition, when described as "X or more" (X is an arbitrary number), it includes the meaning of "preferably greater than X" unless otherwise specified, and is described as "Y or less" (Y is an arbitrary number). If not otherwise specified, it also includes the meaning of "preferably smaller than Y".

The invention is further illustrated by the following examples. The examples are not intended to limit the invention in any way.
It should be noted that various production conditions and values of evaluation results in the following examples have the meaning of preferred values for the upper limit or lower limit in the embodiments of the present invention, and the preferred range is the above-described upper limit or lower limit value. , the range defined by the values in the following examples or a combination of the values in the examples. In the following, all "parts" indicate "mass parts".

[Various analysis/evaluation/measurement methods]
The analysis, evaluation, and measurement methods of various physical properties and characteristics are as follows.

(1) Tensile storage modulus, glass transition temperature JIS K 7244-4: According to the dynamic viscoelasticity measuring method described in 1999, a dynamic viscoelasticity measuring device ("DVA-200" manufactured by IT Keisoku Co., Ltd.) was used. Measurement was performed under the conditions of a frequency of 1 Hz, a temperature increase rate of 3°C/min, and a double-end tensile mode, and the storage elastic modulus E' at 100°C, 150°C, and 200°C was obtained.
Further, the temperature at which the peak of tan δ obtained from loss elastic modulus E″/storage elastic modulus E′ was obtained was taken as the glass transition temperature (Tg).

(2) Peel strength between epoxy resin sheet (A) and carrier sheet (B) Laminated bodies (samples) prepared in Examples and Comparative Examples were cut into 15 mm wide x 250 mm long test pieces, which were used for universal material testing. Using a machine (“AGS-X” manufactured by Shimadzu Corporation), a T-type peel test was performed on the interface between the epoxy resin sheet (A) and the carrier sheet (B) at a test speed of 50 mm / min, and the displacement was 30 mm. The peel strength was defined as the average value of the peel strength up to 60 mm.

(3) Peel Strength Between Epoxy Resin Sheets (A) The peeling interfaces of the two epoxy resin sheets (A) from which the carrier sheet (B) has been peeled off are pasted together and brought into close contact with each other by a hand roller. .The T-type peel test between the epoxy resin sheets (A) (A) was performed in the same manner as in (2) above for the sample laminated under pressure of 1 MPa, and the average value of the peel force between displacements of 30 mm and 60 mm. was taken as the peel strength.

(4) Hysteresis loss The average value of hysteresis loss at 23°C was obtained by the following method according to JIS K 7312:1996.
As a measuring device, a tensile tester (manufactured by Shimadzu Corporation, tensile tester AG-1kNXplus) was used. The epoxy resin sheet (A) obtained by removing the carrier sheet (B) from the laminate (sample) prepared in Examples and Comparative Examples was cut into a width of 10 mm and a length of 100 mm, and used as a test piece.
Both ends of the test piece in the longitudinal direction are chucked at a distance between chucks of 50 mm, and the strain is raised to 50% at a crosshead speed of 300 mm / min, then held for 2 seconds, and then lowered to the initial position at the same speed. A stress-strain curve was obtained from one cycle of tensile cycle testing. The stress - strain curve takes a profile as shown in FIG. 1, the hysteresis loss is the resulting stress - from the strain curve, the area A1 of the curve obtained in the upward motion (area surrounded by abcda in FIG. 1) and the area A2 (the area surrounded by abcef in FIG. 1), which is the difference between the areas of the curves obtained in the descending motion, was used for calculation by the following formula. The test was measured 3 times and the average value was calculated.
Hysteresis loss = (A2/A1) x 100

(5) Thickness
For the thickness of the epoxy resin sheet (A), the thickness of two carrier sheets (B) was set as a reference thickness (0 μm) using a micrometer, and the A4 size laminate sample was measured from the end in the width direction. The thickness was measured at three locations at intervals of 100 mm, and the average value was obtained.
The thickness of the laminate was obtained by calculating the sum of the thickness of the epoxy resin sheet (A) obtained above and the thickness of the two carrier sheets (B).

(6) Restorability after stretching A marked line with an initial inter-mark distance L1 of 100 mm was drawn in the length direction on the epoxy resin sheet (A) having a width of 10 mm and a length of 150 mm.
Set the epoxy resin sheet (A) in a tensile tester with a gauge line distance of 100 mm (same as the distance between chucks) under an ambient temperature of 23°C, and stretch it up to 120% (displacement distance: 20 mm) at a tensile speed of 200 mm/min. After stretching and holding the stretched state for 1 minute, release the tensile load, measure the distance L2 between the gauge marks after 1 minute and 5 minutes after release, and calculate the recovery rate (%) by the following formula. asked.
Recovery rate (%) = ((120-L2) / (120-L1)) x 100

Restorability was evaluated according to the following criteria based on the restoration rate at 1 minute and 5 minutes after releasing the tensile load.
○ (very good): 99% or more after 1 minute and 5 minutes △ (good): 98% or more after 1 minute and 5 minutes, one less than 99% × (poor): Less than 98% at either 1 minute or 5 minutes

(7) Evaluation of tackiness Evaluation of tackiness for examining suitability for process sheets was performed by the following method.
Two epoxy resin sheets (A) each having a width of 15 mm and a length of 100 mm were laminated together with a hand roller, heated at 50°C for 1 minute, and separated by hand at 30°C. Evaluation was made according to the following criteria.
◯ (good): Easy peeling without wrinkles.
(triangle|delta) (usual): Slight elongation, peelable × (poor): Sheet fracture or sheet elongation, and peeling is difficult.

In Examples and Comparative Examples, epoxy resin sheets (A) and laminates were produced as follows.

<Materials used for epoxy resin sheet (A)>
(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.
141.8 parts by mass of 1,6-hexanediol preheated to 45°C and 0.51 parts by mass of boron trifluoride ethyl ether were charged in a 1 L glass flask equipped with a stirrer, dropping funnel and thermometer, and the mixture was heated to 80°C. heated to 244.3 parts by mass of epichlorohydrin was added dropwise over time so that the temperature did not exceed 85°C. After aging for 1 hour while maintaining the temperature at 80 to 85°C, the mixture was cooled to 45°C. 528.0 parts by mass of a 22% by mass sodium hydroxide aqueous solution was added thereto, and vigorously stirred at 45° C. for 4 hours. After cooling to room temperature, the aqueous phase was separated and removed, and unreacted epichlorohydrin and water were removed by heating under reduced pressure to obtain 283.6 parts by mass of crude 1,6-hexanediol diglycidyl ether.
This crude 1,6-hexanediol diglycidyl ether was purified by distillation in an Oldershaw distillation column (15 stages), and the fraction at a pressure of 1300 Pa and 170 to 190 ° C. was used as the main fraction, and gas chromatography was performed. 127.6 parts by mass of 1,6-hexanediol diglycidyl ether having a diglycidyl purity of 97% by mass, a total chlorine content of 0.15% by mass, and an epoxy equivalent of 116 g/equivalent was obtained.
100 parts by weight of the 1,6-hexanediol diglycidyl ether, 69.3 parts by weight of bisphenol F (phenolic hydroxyl group equivalent: 100 g/equivalent), 0.13 parts by weight of ethyltriphenylphosphonium iodide (30% by weight methyl cellosolve solution) Part is placed in a pressure-resistant reaction vessel, and a polymerization reaction is performed at 165 to 170 ° C. for 5 hours in a nitrogen gas atmosphere to obtain bisphenol F and 1 having an epoxy equivalent of 1,000 g / equivalent and a number average molecular weight of 3,000. ,6-hexanediol diglycidyl ether was obtained.

(Aliphatic epoxy resin (β1))
Polytetramethylene glycol diglycidyl ether (epoxy equivalent: 440 g/equivalent) was used as the aliphatic epoxy resin (β1).

(curing agent)
As a curing agent, an alicyclic polyamine (“jER Cure ST-14” manufactured by Mitsubishi Chemical Corporation) (active hydrogen equivalent: 85 g/equivalent) was used.

(filler)
As a filler, fumed silica “Aerosil RX200 manufactured by EVONIK” was used.

<Urethane sheet>
As the urethane sheet, an 80 μm-thick urethane sheet made of a polyurethane elastomer laminated sheet (trade name “Silklon SES85-NW/PP”) manufactured by Okura Kogyo Co., Ltd. was used.

<Carrier sheet (B)>
As the carrier sheet (B1), a PET film (manufactured by Mitsubishi Chemical Corporation, release-coated PET film "MRF75", thickness 75 µm; film containing a polyester film and a release layer) was used.
As the carrier sheet (B2), a PE/PET film (a 2-kind 2-kind film in which a 50-μm-thick low-density polyethylene film and a 50-μm-thick biaxially-stretched polyethylene elephthalate film are bonded together) was used.

[Example 1]
An epoxy resin composition was prepared by blending 50 parts by mass of the epoxy resin (α1), 50 parts by mass of the aliphatic epoxy resin (β1), and 15.2 parts by mass of the alicyclic polyamine.
This epoxy resin composition is applied onto the release layer of the first carrier sheet (B1), and the second carrier sheet (B1 ) were laminated and pasted together. The obtained sample was subjected to a primary heat treatment at 40° C. for 16 hours and a secondary heat treatment at 80° C. for 6 hours to obtain a laminate consisting of carrier sheet (B1)/epoxy resin sheet (A)/carrier sheet (B1). A body (sample) was produced.

[Example 2]
An epoxy resin composition was prepared by blending 67 parts by mass of the epoxy resin (α1), 33 parts by mass of the aliphatic epoxy resin (β1), 13 parts by mass of the alicyclic polyamine, and 5 parts by mass of the filler. A laminate (sample) was produced in the same manner as in Example 1 except for the above.

[Example 3]
75 parts by mass of the epoxy resin (α1), 25 parts by mass of the aliphatic epoxy resin (β1), 11.7 parts by mass of the alicyclic polyamine, and 5 parts by mass of the filler are blended to form an epoxy resin composition. A laminate (sample) was produced in the same manner as in Example 1 except for the preparation.

[Example 4]
An epoxy resin composition was prepared by blending 90 parts by mass of the epoxy resin (α1), 10 parts by mass of the epoxy resin (β1), and 9.77 parts by mass of the alicyclic polyamine, and the carrier sheet (B1) was prepared. A laminate (sample) was produced in the same manner as in Example 1, except that the carrier sheet (B2) was used instead.

[Comparative Example 1]
A laminate (sample) was produced in the same manner as in Example 1, except that the epoxy resin composition was prepared by blending 100 parts by mass of the epoxy resin (α1) and 8.5 parts by mass of the alicyclic polyamine. bottom.

[Comparative Example 2]
The urethane sheet was laminated on the release layer of the first carrier sheet (B1), and the second carrier sheet (B1) was laminated on the urethane sheet to prepare a laminate (sample).

In the above examples, epoxy obtained from a resin composition in which polytetramethylene glycol diglycidyl ether as the aliphatic epoxy resin (β) and an epoxy resin (α) having a block structure of a rigid component and a flexible component are combined. The resin sheet exhibited low hysteresis loss and high restorability. Furthermore, it was found that the epoxy resin sheets of the examples have appropriate peel strength between sheets and exhibit suitable tackiness for use as process sheets.
The added aliphatic epoxy resin (β) is compatible with the epoxy resin (α), and the hydrogen bond between the aliphatic epoxy resin (β) and the epoxy resin (α) allows free movement in the epoxy resin (α). It is thought that the free ends with high σ were restrained and the energy loss when subjected to stress could be suppressed, and as a result, the resilience could be improved. Considering such a mechanism of action, as the aliphatic epoxy resin (β), if it is an epoxy resin having an aliphatic ether unit that is compatible with the epoxy resin (α), the same polytetramethylene glycol diglycidyl ether can be used. It is thought that this shows the effect.

Claims (23)

An epoxy resin sheet having a hysteresis loss of 40% or less after maintaining 50% elongation for 2 seconds in tensile mode, measured according to JIS K 7312:1996. 2. The epoxy resin sheet according to claim 1, which has a tensile storage modulus of 1.0×10 ⁴ to 6.0×10 ⁷ Pa at 100 to 200°C. 3. The epoxy resin sheet according to claim 1, wherein the sheet-to-sheet peel strength is in the range of 0.05 to 2.5 N/15 mm. The epoxy resin sheet according to any one of claims 1 to 3, which has a glass transition temperature of 20°C or less. The epoxy resin sheet according to any one of claims 1 to 4, having an average thickness of 10 to 500 µm. The epoxy resin sheet according to any one of claims 1 to 5, comprising a cured product obtained by curing an epoxy resin composition containing an epoxy resin and a curing agent. 7. The epoxy resin sheet according to claim 6, wherein said curing agent is an alicyclic polyamine. The epoxy according to any one of claims 1 to 7, wherein the epoxy resin composition comprises an epoxy resin (α) having a block structure of a rigid component and a flexible component, and an aliphatic epoxy resin (β). resin sheet. The epoxy resin sheet according to claim 8, wherein the aliphatic epoxy resin (β) is an epoxy resin having an aliphatic ether unit. The epoxy resin sheet according to claim 8 or 9, wherein the aliphatic epoxy resin (β) is polyalkylene glycol diglycidyl ether. The epoxy resin sheet according to any one of claims 8 to 10, wherein the epoxy resin (α) is an epoxy resin having a bisphenol F unit and an alkyldiol diglycidyl ether unit. 12. The epoxy resin sheet according to any one of claims 1 to 11, which is used as a release material, a cushioning material, or an anti-slip material. A stretchable member comprising the epoxy resin sheet according to any one of claims 1 to 11. A flexible member comprising the epoxy resin sheet according to any one of claims 1 to 11. A laminate comprising a carrier sheet on at least one side of the epoxy resin sheet according to any one of claims 1 to 11. A laminate comprising a carrier sheet on at least one side of the epoxy resin sheet according to any one of claims 1 to 11 with a release layer interposed therebetween. 17. The laminate according to claim 15 or 16, having a tensile storage modulus at 100-200° C. of 6.0×10 ⁷ to 1.0×10 ¹⁰ Pa. The laminate according to any one of claims 15 to 17, wherein the carrier sheet is any one of polyester film, polyimide film and copper foil. The laminate according to any one of claims 15 to 18, which is used as a release material, a cushioning material, or an anti-slip material. A stretchable member comprising the laminate according to any one of claims 15-18. A flexible member comprising the laminate according to any one of claims 15-18. A wound body in which a laminate comprising an epoxy resin sheet and a carrier sheet on at least one side of the epoxy resin sheet is wound around a core,
A wound body having a hysteresis loss of 40% or less after maintaining 50% elongation for 2 seconds in the tensile mode of the epoxy resin sheet, measured according to JIS K 7312:1996. The wound body according to claim 22, wherein the epoxy resin sheet is the epoxy resin sheet according to any one of claims 2 to 11.

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