Epoxy resin sheets, laminates, stretchable members, flexible members, and winding bodies

Abstract

To provide an epoxy resin sheet having restorability after stretching.SOLUTION: An epoxy resin sheet has a hysteresis loss of 40% or less after the 50% elongation kept for 2 seconds at a tensile mode, measured in accordance with JIS K 7312: 1996.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a sheet whose main component is epoxy resin (referred to as "epoxy resin sheet"), a laminate and a wound body equipped with the 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 performance of electrical and electronic components have led to a growing demand for epoxy resins with high moldability. Recently, development has also been underway to utilize epoxy resins in applications where flexibility is paramount, such as flexible laminates and stretchable laminates.

[0003] For example, Patent Document 1 discloses a specific highly flexible epoxy resin, and describes that a resin composition containing this epoxy resin yields a cured product that has a good balance of adhesiveness and electrical properties while also possessing high flexibility.

[0004] Patent Document 2 discloses a resin composition that is flexible and has excellent resilience and stress relaxation properties after stretching, comprising at least (A) polyrotaxane, (B) epoxy resin, and (C) curing agent, wherein the proportion of (B) epoxy resin is 30 to 50 parts by mass, based on a total of 100 parts by mass of (A) polyrotaxane, (B) epoxy resin, and (C) curing agent.

[0005] Patent Document 3 describes a laminate that can suppress problems such as elongation, bending, and wrinkle formation of epoxy resin sheets during secondary processing, comprising an epoxy resin sheet made of a cured product obtained by curing an epoxy resin composition containing an epoxy resin having a block structure of rigid and flexible components and an alicyclic polyamine, and a carrier sheet on at least one side of the epoxy resin sheet, This epoxy resin sheet has a tensile storage modulus of 1.0 × 10⁻¹⁰ at 100°C to 200°C.4 ~6.0×10 7 It is Pa, and the tensile elongation is 150% or more. The tensile storage modulus of the laminate at 100°C to 200°C is 6.0 × 10⁻⁶. 7 ~1.0×10 10 A laminate is disclosed that is Pa. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2005-320477 [Patent Document 2] Japanese Patent Publication No. 2018-172697 [Patent Document 3] WO2020 / 027291 issue [Overview of the project] [Problems that the invention aims to solve]

[0007] In semiconductor manufacturing processes and other applications, cushioning materials primarily composed of urethane resin or silicone resin have traditionally been used. As mentioned earlier, epoxy resin has excellent heat resistance, adhesiveness, mechanical strength, and electrical properties. Therefore, if epoxy resin sheets can be given resilience, it is expected that they can be used in new applications such as cushioning materials.

[0008] Therefore, the present invention aims to provide an epoxy resin sheet having resilience after stretching, as well as a laminate and a wound body using the epoxy resin sheet. [Means for solving the problem]

[0009] This invention proposes an epoxy resin sheet in which the hysteresis loss after maintaining a 50% elongation in tensile mode for 2 seconds, as measured in accordance with JIS K 7312:1996, is 40% or less.

[0010] The present invention also proposes a laminate having a carrier sheet on at least one side of the epoxy resin sheet.

[0011] The present invention also relates to 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, and proposes a wound body in which the hysteresis loss after maintaining 50% elongation for 2 seconds in the tensile mode of the epoxy resin sheet, measured according to JIS K 7312:1996, is 40% or less.

Effects of the Invention

[0012] The epoxy resin sheet proposed by the present invention has resilience after stretching. Further, as described above, the epoxy resin has properties such as excellent heat resistance, adhesiveness, mechanical strength, and electrical properties. Therefore, the epoxy resin sheet proposed by the present invention can be repeatedly used as, for example, a member used in a semiconductor manufacturing process, specifically, a release material, a cushioning material, an anti-slip material, etc., and thus can be expected to be effectively utilized for new applications.

Brief Description of the Drawings

[0013] [Figure 1] It is a diagram showing a conceptual diagram of a stress-strain curve used when obtaining the hysteresis loss and a relational expression for obtaining the hysteresis loss.

Embodiments for Carrying Out the Invention

[0014] Next, the present invention will be described based on an example of an embodiment. However, the present invention is not limited to the embodiments described below.

[0015] <The present epoxy resin sheet> An epoxy resin sheet (referred to as "the present epoxy resin sheet") according to an example of an embodiment of the present invention is a sheet formed from an epoxy resin composition having an epoxy resin as a main resin.

[0016] In addition, in this specification, the term "epoxy resin" refers to both the raw material resin before curing and the resin (cured product) after curing. Since the epoxy groups are consumed by the curing reaction, the resin after curing may not have epoxy groups (epoxy structure), but in this specification, these are not distinguished.

[0017] (Hysteresis loss) This epoxy resin sheet preferably has a hysteresis loss of 40% or less after maintaining 50% elongation for 2 seconds in the tensile mode, more preferably 30% or less, and even more preferably 25% or less, measured in accordance with JIS K 7312:1996. The lower limit value of the hysteresis loss is not particularly limited, but is usually 3% or more. If the hysteresis loss of this epoxy resin sheet is within the above range, it has excellent resilience after elongation. For example, the degree of deformation is small before and after use in release materials, cushioning materials, anti-slip materials, etc., and it can be repeatedly used, which is preferable. In addition, the hysteresis loss of this epoxy resin sheet is specifically measured by the method described in the examples.

[0018] (Tensile storage modulus) The tensile storage modulus of this epoxy resin sheet at 100°C to 200°C is preferably 1.0×10 4 Pa to 6.0×10 7 Pa, more preferably 6.0×10 4 Pa or more or 1.0×10 7 Pa or less, and even 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 ~6.0×10 7 Pa" means that in the entire temperature range of 100°C to 200°C, the tensile storage modulus maintains a value of 1.0×10 4 or more and 6.0×10 7 Pa or less. If the tensile storage modulus of this epoxy resin sheet is within the above range, it is preferable because it is a sheet with superior elasticity compared to ordinary epoxy resin sheets. The tensile storage modulus of this epoxy resin sheet can be measured specifically by the method described in the examples.

[0019] (Peel strength) The peel strength between these epoxy resin sheets is preferably 0.05 N / 15 mm to 2.5 N / 15 mm, more preferably 0.1 N / 15 mm or more or 2 N / 15 mm or less, more preferably 0.2 N / 15 mm or more or 1.5 N / 15 mm or less, and especially preferably 0.3 N / 15 mm or more or 1 N / 15 mm or less. If the tensile storage modulus of these epoxy resin sheets is within the above range, they will have appropriate tackiness when used as a release agent, cushioning material, or anti-slip material. This will allow for an anti-slip effect on components placed on the surface of the epoxy resin sheet, while also allowing for easy removal of the epoxy resin sheet from the component without the risk of stretching. As a result, the epoxy resin sheet can be reused repeatedly. The peel strength between these epoxy resin sheets can be measured specifically by the method described in the examples.

[0020] (Glass transition temperature) The epoxy resin sheet preferably has a glass transition temperature of 20°C or lower. The glass transition temperature of typical epoxy resin sheets is around 110-130°C. Therefore, if the glass transition temperature of this epoxy resin sheet is 20°C or lower, it can be said that its glass transition temperature is significantly lower than that of typical epoxy resin sheets. Epoxy resin sheets with a glass transition temperature of 20°C or lower are preferable from the viewpoint of flexibility and pliability. From the viewpoint of enabling the flexible material to be used over a wider temperature range, the glass transition temperature of this epoxy resin sheet is preferably 20°C or lower, more preferably 15°C or lower, and even more preferably 10°C or lower. However, if the glass transition temperature is too low, the handling of the film may deteriorate, such as wrinkles forming or the film tearing with even a small force. Considering this point, the glass transition temperature of this epoxy resin sheet is preferably -40°C or higher, more preferably -30°C or higher, and even more preferably -25°C or higher. The glass transition temperature of this epoxy resin sheet can be adjusted, for example, by the type and content ratio of the epoxy resin (α) and aliphatic epoxy resin (β) described later. From this viewpoint, it is preferable that the epoxy resin (α) and aliphatic epoxy resin (β) are mutually compatible, that a single glass transition temperature appears, and that the aliphatic epoxy resin (β) can lower the glass transition temperature. The glass transition temperature of the epoxy resin sheet can be measured specifically by the method described in the examples.

[0021] (thickness) From the viewpoint of manufacturing and practical application, the average thickness of this epoxy resin sheet is preferably 10 μm to 500 μm, and more preferably 20 μm or more or 200 μm or less, of which 30 μm or more or 150 μm or less, and of which 50 μm or more or 140 μm or less. The average thickness of this epoxy resin sheet can be determined by measuring the thickness at at least three points using a micrometer and taking the arithmetic mean of those measurements.

[0022] (Epoxy resin composition (a)) The epoxy resin sheet is preferably a sheet-like molded article made from a cured product of a resin composition (hereinafter referred to as "epoxy resin composition (a)") which contains epoxy resin as the main component resin, a curing agent, and optionally other components.

[0023] The term "main component resin" refers to the resin with the highest mass percentage among the resin components constituting the epoxy resin composition (a). For example, it can be assumed that it accounts for 50% or more by mass, 60% or more by mass, 70% or more by mass, 80% or more by mass, 90% or more by mass, or 100% by mass of the resin components constituting the epoxy resin composition (a). Furthermore, "curing" means intentionally hardening the epoxy resin composition (a) by heat and / or light, etc. Here, "intentionally" includes cases where, for example, the epoxy resin sheet before curing hardens gradually due to the effects of heat and light over time when stored for a long period of time.

[0024] (Epoxy resin) The epoxy resin in epoxy resin composition (a) preferably contains an epoxy resin (α) having a block structure of rigid and flexible components, and an aliphatic epoxy resin (β). By incorporating an aliphatic epoxy resin (β) into the epoxy resin (α) of this epoxy resin sheet, the hysteresis loss of this epoxy resin sheet can be reduced. As mentioned above, from the viewpoint of adjusting the glass transition temperature of this epoxy resin sheet, it is preferable that the epoxy resin (α) and the aliphatic epoxy resin (β) are mutually compatible, resulting in the appearance of a single glass transition temperature, and that the aliphatic epoxy resin (β) can lower the glass transition temperature.

[0025] [Epoxy resin (α)] Epoxy resin (α) is an epoxy resin having a block structure of rigid and flexible components. By including such epoxy resin (α), it becomes possible to impart flexibility to the cured product.

[0026] The rigid component preferably has an aromatic ring structure, such as a condensed aromatic ring structure including 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.

[0027] On the other hand, the flexible component preferably contains aliphatic hydrocarbons, such as alkylene groups having 1 to 8 carbon atoms, ethylene glycol groups, propylene glycol groups, and butylene glycol groups.

[0028] Furthermore, the epoxy resin (α) does not necessarily have to have epoxy groups or epoxy group-derived structures in both the rigid and flexible components. That is, it is sufficient if at least one of the rigid or flexible components has epoxy groups or epoxy group-derived structures. From the viewpoint of imparting flexibility while retaining the inherent properties of epoxy resin such as heat resistance and mechanical strength, it is preferable that only one of the rigid or flexible components has epoxy groups or epoxy group-derived structures.

[0029] Specific examples of epoxy resin (α) include epoxy resins containing 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), 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").Copolymers of (others similarly), copolymer of 1,6-hexanediol and bisphenol F diglycidyl ether, copolymer of bisphenol F and 1,4-butanediol diglycidyl ether, copolymer of 1,4-butanediol and bisphenol F diglycidyl ether, copolymer of bisphenol A and 1,6-hexanediol diglycidyl ether, copolymer of 1,6-hexanediol and 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 biphenol and 1,6-hexanediol diglycidyl ether Copolymer with -tel, copolymer of 1,6-hexanediol and biphenol diglycidyl ether, copolymer of biphenol and 1,4-butanediol diglycidyl ether, copolymer of 1,4-butanediol and biphenol diglycidyl ether, copolymer of 1,4-naphthalenediol and 1,6-hexanediol diglycidyl ether, copolymer of 1,6-hexanediol and 1,4-naphthalenediol diglycidyl ether, copolymer of 1,4-naphthalenediol and 1,4-butanediol diglycidyl Examples include copolymers with ethers, copolymers of 1,4-butanediol and 1,4-naphthalenediol diglycidyl ether, copolymers of 1,6-naphthalenediol and 1,6-hexanediol diglycidyl ether, copolymers of 1,6-hexanediol and 1,6-naphthalenediol diglycidyl ether, copolymers of 1,6-naphthalenediol and 1,4-butanediol diglycidyl ether, and copolymers of 1,4-butanediol and 1,6-naphthalenediol diglycidyl ether. Furthermore, the epoxy equivalent of epoxy resin (α) is preferably 300 to 5000 g / equivalent, and more preferably 500 g / equivalent or more, or 2000 g / equivalent or less, from the viewpoint of maintaining the flexibility of the epoxy cured product. These may be used individually, or two or more may be mixed in any combination and ratio. Among these, from the viewpoint of flexibility, epoxy resin (α) is preferably a copolymer of bisphenol F and alkyldiol diglycidyl ether, and among these, a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether.

[0030] [Aliphatic epoxy resin (β)] Aliphatic epoxy resin (β) is an epoxy resin having a non-aromatic carbon chain, which may be acyclic or cyclic, linear or branched, and the bonds may be saturated or unsaturated. Furthermore, the number of functional groups may be monofunctional or polyfunctional (two or more functional groups). This epoxy resin sheet, formed from an epoxy resin composition containing a softer aliphatic epoxy resin (β) than the relatively hard aliphatic epoxy resin (α), exhibits low hysteresis loss and excellent resilience. Furthermore, this sheet possesses moderate tackiness. Therefore, it can be expected to provide an anti-slip effect on components placed on its surface, while also being easy to peel off from those components, allowing for repeated use of the epoxy resin sheet.

[0031] Examples of aliphatic epoxy resins (β) include epoxy resins formed from glycidyl aliphatic alcohols or polyols. For example, monoepoxy compounds such as monoglycidyl ethers of aliphatic alcohols and glycidyl esters of alkyl carboxylic acids, and polyfunctional epoxy compounds such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts and polyglycidyl esters of aliphatic long-chain polybasic acids.

[0032] Specific examples of monomer components that make up aliphatic epoxy resin (β) include allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, C11-13 mixed alkyl glycidyl ether (a mixture of alkyl glycidyl ethers with 11-13 carbon atoms in the alkyl group), 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and sorbitol tetraglycidyl ether. Examples include glycidyl ethers of polyhydric alcohols such as glycidyl ethers, hexaglycidyl ethers of dipentaerythritol, diglycidyl ethers of polyethylene glycol, diglycidyl ethers of polypropylene glycol, diglycidyl ethers of polyglycerin, diethylene glycol, polyethylene glycol, and polyglycerin, or polyglycidyl ether compounds of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as propylene glycol, trimethylolpropane, and glycerin, as well as diglycidyl esters of aliphatic long-chain dibasic acids. Furthermore, examples include monoglycidyl ethers of aliphatic higher alcohols, glycidyl esters of higher fatty acids, epoxidized soybean oil, octyl epoxystearate, butyl epoxystearate, epoxidized soybean oil, and epoxidized polybutadiene. Aliphatic epoxy resin (β) may be used alone or in combination of two or more types.

[0033] In particular, from the viewpoint of further enhancing the resilience of the epoxy resin sheet, the aliphatic epoxy resin (β) is preferably an epoxy resin having aliphatic ether units, and among these, an epoxy resin obtained from polyether glycol is preferred.

[0034] Examples of epoxy resins obtained from polyether glycols include epoxy resins resulting from the reaction of one or more glycols, such as ethylene glycol, propylene glycol, tetramethylene ether glycol, and neopentyl glycol, with epichlorohydrin. Furthermore, from the viewpoint of maintaining the flexibility of the epoxy cured product, the epoxy equivalent of the polyether glycol is preferably 100 to 2000 g / equivalent, and more preferably 250 g / equivalent or more, or 1500 g / equivalent or less. The epoxy resin obtained from polyether glycol may be used alone or as a mixture of two or more types.

[0035] In particular, from the viewpoint of further enhancing the resilience of the epoxy resin sheet, the aliphatic epoxy resin (β) is preferably aliphatic polyglycidyl ethers. Examples of aliphatic polyglycidyl ethers include 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, and polypropylene glycol diglycidyl ether, as well as alkyl glycidyl ethers. It is believed that by mixing these aliphatic polyglycidyl ethers with the epoxy resin (α), they become compatible with the epoxy resin (α), thereby further enhancing the resilience of the epoxy resin sheet.

[0036] Regarding the content ratio of aliphatic epoxy resin (β), from the viewpoint of improving resilience, it is preferable to increase the content of aliphatic epoxy resin (β). However, if the proportion of aliphatic epoxy resin (β) is too high, it becomes difficult to maintain strength. From this viewpoint, it is preferable that the aliphatic epoxy resin (β) in the total of epoxy resin (α) and aliphatic epoxy resin (β) as solid content in epoxy resin composition (a) be 5 to 80% by mass, and more preferably 5% by mass or more or 50% by mass or less, of which 10% by mass or more or 40% by mass or less, and of which 15% by mass or more or 35% by mass or less. Here, the term "solid content" refers to the components excluding the solvent, and includes not only solid epoxy resins or epoxy compounds, but also semi-solid and viscous liquid substances.

[0037] [Filling material] The epoxy resin composition (a) may optionally include fillers. By blending fillers into epoxy resin composition (a), the viscosity of epoxy resin composition (a) increases, making it easier to handle, and also increasing the strength of the epoxy resin sheet. For example, by blending inorganic fillers into epoxy resin composition (a) with the aim of improving various properties such as reducing the curing shrinkage rate and decreasing the thermal expansion coefficient of the resulting cured product, applications can be developed in the electrical and electronic fields, particularly in liquid semiconductor encapsulants. Furthermore, it is conceivable to include organic fillers such as rubber particles or acrylic particles to impart toughness.

[0038] Examples of such fillers include powdered reinforcing materials and fillers, such as metal oxides like aluminum oxide and magnesium oxide, metal carbonates like calcium carbonate and magnesium carbonate, diatomaceous earth powder, basic magnesium silicate, calcined clay, fine silica powder, fused silica, silicon compounds like zeolite, metal hydroxides like aluminum hydroxide, and others such as kaolin, mica, quartz powder, graphite, carbon black, carbon nanotubes, molybdenum disulfide, boron nitride, and aluminum nitride.

[0039] Furthermore, fibrous reinforcing materials and fillers can also be incorporated as fillers. Examples of fibrous reinforcing or filling materials include glass fibers, ceramic fibers, carbon fibers, alumina fibers, silicon carbide fibers, boron fibers, aramid fibers, cellulose nanofibers, and cellulose nanocrystals. Organic and inorganic fiber cloths or nonwoven fabrics can also be used.

[0040] The above-mentioned filler may be surface-treated with a silane coupling agent, titanate-based coupling agent, aluminate-based coupling agent, or a primer.

[0041] When adding fillers, it is preferable to ensure that the tensile storage modulus of the epoxy resin sheet is within the above range. From this viewpoint, the content of these fillers is preferably 0.1 parts by mass or more and 900 parts by mass or less per 100 parts by mass of the sum of the epoxy resin amount (total of epoxy resin (α) and aliphatic epoxy resin (β), the same applies hereinafter) and the amount of curing agent, and more preferably 1 part by mass or more or 500 parts by mass or less, and more preferably 3 parts by mass or more or 100 parts by mass or less.

[0042] [Hardening agent] The curing agent of epoxy resin composition (a) is preferably a group that is reactive with the epoxy groups of at least epoxy resin (α) to aliphatic epoxy resin (β), in other words, a substance that contributes to the crosslinking reaction between crosslinking groups. Such curing agents can be those generally known as epoxy resin curing agents. Examples include phenolic curing agents, aliphatic amines, polyetheramines, alicyclic amines, aromatic amines and other amine-based curing agents, acid anhydride-based curing agents, amide-based curing agents, tertiary amines, imidazoles and their derivatives, organophosphines, phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, boron halogenated amine complexes, polymercaptan-based curing agents, isocyanate-based curing agents, and blocked isocyanate-based curing agents. These may be used individually or in combination of two or more. In particular, from the viewpoint of high transparency and minimal discoloration, a curing agent having an alicyclic structure is preferred as the curing agent.

[0043] The curing agent having an alicyclic structure is preferably a substance that has an alicyclic structure and contributes to the crosslinking reaction and / or chain length extension reaction between epoxy groups of the epoxy resin. Examples include alicyclic polyamines and alicyclic acid anhydrides. More specifically, examples include alicyclic polyamines such as 1,4-diazabicyclo-2,2,2-octane, 1,8-diazabicyclo-5,4,0-undeca-7-ene, N,N'-dimethylpiperazine, N-aminoethylpiperazine, mensendiamine, isophoronediamine, hexamethylenetetramine, methylenebiscyclohexanamine, 1,3-bisaminomethylcyclohexane, norbornenediamine, and 1,2-diaminocyclohexane, as well as modified alicyclic polyamines obtained by epoxy modification, ethylene oxide modification, dimer acid modification, Mannich modification, Michael addition, thiourea condensation, or ketimination of these alicyclic polyamines, and hexahydrophthalic anhydride and methylhexahydrophthalic anhydride. These may be used individually or in combination of two or more. Among these, alicyclic polyamines are preferred, and among them, isophoronediamine, hexamethylenetetramine, methylenebiscyclohexanamine, 1,3-bisaminomethylcyclohexane, norbornenediamine, 1,2-diaminocyclohexane, and modified versions thereof are particularly preferred. From the viewpoint of maintaining the flexibility of the epoxy cured product, the active hydrogen equivalent of the curing agent is preferably 10 to 500 g / equivalent, and more preferably 50 g / equivalent or more, or 250 g / equivalent or less.

[0044] Commercially available curing agents with an alicyclic structure can also be used, such as "jER Cure 113" and "jER Cure ST-14" from Mitsubishi Chemical Corporation, and "Ricacid MH-700" from Shin Nippon Rika Co., Ltd.

[0045] The amount of curing agent in epoxy resin composition (a) (if a curing agent other than a curing agent having an alicyclic structure is used, this is the total amount of the curing agent having an alicyclic structure and the other curing agent, the same applies hereinafter) is preferably 0.1 to 100 parts by mass per 100 parts by mass of epoxy resin (total amount of epoxy resin (α) and aliphatic epoxy resin (β)), and more preferably 1 part by mass or more or 80 parts by mass or less, of which 5 parts by mass or more or 60 parts by mass or less, and of which 8 parts by mass or more or 40 parts by mass or less.

[0046] [solvent] The epoxy resin composition (a) may be diluted with a solvent as needed to adjust its viscosity appropriately during handling, such as when forming a coating film. In epoxy resin composition (a), the solvent is used to ensure ease of handling and workability when preparing epoxy resin composition (a), and there are no particular restrictions on the amount used. In this invention, the terms "solvent" and "solvent" are used to distinguish between their respective uses, but the same or different types may be used independently.

[0047] Examples of solvents that the epoxy resin composition (a) may contain include acetone, methyl ethyl ketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate, ethylene glycol monomethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, methanol, ethanol, etc., and these solvents can also be used as a mixture of two or more solvents as appropriate.

[0048] [Other ingredients] The epoxy resin composition (a) may contain "other components" in addition to the components listed above. These "other components" can be used in appropriate combinations depending on the desired physical properties of the epoxy resin composition (a). Specifically, epoxy resin composition (a) may optionally contain coupling agents, plasticizers, diluents, flexibility-imparting agents, dispersants, wetting agents, colorants, pigments, UV absorbers, light stabilizers such as hindered amine-based light stabilizers, antioxidants, defoaming agents, release agents, flow regulators, etc. 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 (total amount of epoxy resin (α) and aliphatic epoxy resin (β)) and the amount of curing agent. On the other hand, the lower limit is not particularly limited, but 0.1 parts by mass or more is preferred.

[0049] Furthermore, in order to improve 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 more combinations of cyanate ester resins, acrylic resins, silicone resins, urethane resins, polyester resins, etc., can be cited. The content ratio of these resins is preferably within a range that does not impair the original properties of the epoxy resin composition (a), that is, 50 parts by mass or less per 100 parts by mass of the sum of the epoxy resin amount (total amount of epoxy resin (α) and aliphatic epoxy resin (β)) and the amount of curing agent. On the other hand, the lower limit is not particularly limited, but 1.0 part by mass or more is preferred.

[0050] (Manufacturing method of this epoxy resin sheet) This epoxy resin sheet can be manufactured by molding an epoxy resin composition (a) into a sheet of a predetermined thickness and then curing it. Alternatively, it can be manufactured by molding a semi-cured product obtained from the epoxy resin composition (a) into a sheet of a predetermined thickness and then curing it further.

[0051] The curing method for epoxy resin composition (a) varies depending on the components contained in epoxy resin composition (a), their content, and the shape of the contents (e.g., sheet thickness), but typically, a heating method is used, which involves heating at 23 to 200°C for 5 minutes to 24 hours. This heating process is preferably carried out in two stages to minimize curing defects: a primary heating at 23-160°C for 5 minutes to 24 hours, and a secondary heating at 80-200°C, which is 40-177°C higher than the primary heating temperature, for 5 minutes to 24 hours. Furthermore, a three-stage process involving a tertiary heating at 100-200°C, which is higher than the secondary heating temperature, for 5 minutes to 24 hours is expected to further reduce curing defects.

[0052] Furthermore, this epoxy resin sheet may be in a semi-cured state. If the epoxy resin sheet is in a semi-cured state, it may be easier to form it into a rolled body, and secondary processing properties may be improved. When manufacturing this epoxy resin sheet as a semi-cured product, the curing reaction of the epoxy resin composition (a) should be advanced by heating or other means to the extent that the shape can be maintained. If the epoxy resin composition (a) contains a solvent, most of the solvent may be removed by methods such as heating, reduced pressure, or air drying, leaving 5% by mass or less of the solvent in the semi-cured product.

[0053] (Applications of this epoxy resin sheet) Because this epoxy resin sheet has resilience, it can be suitably used as a release agent, cushioning material, anti-slip material (sealing material), etc., in the manufacturing processes of various molded products, especially in press molding, vacuum molding, and pressure molding. In addition, it can be suitably used in various industrial applications, including fields other than electronic and electrical component applications, such as cushioning materials, adhesive sheets, bonding sheets, stretchable tapes, sealing sheets, heat-resistant insulating sheets, heat-resistant conductive sheets, glass substitutes, protective films, medical sheets, agricultural sheets, and construction sheets.

[0054] Furthermore, this epoxy resin sheet can also be used as a flexible or stretchable plate where flexibility is important. Examples of flexible or stretchable plates include printed circuit boards with laminated metal foils such as copper foil. In other words, this epoxy resin sheet can be used as a flexible or stretchable component. As an example of a method for manufacturing the printed circuit board, one can be described as a method in which copper foil is layered on one or both sides of the epoxy resin sheet, and a copper-clad laminate is produced by hot press molding using a vacuum press or the like, and a wiring pattern is formed by etching to obtain a printed circuit board. Examples of wiring patterns include printed circuit boards using conductive paste.

[0055] An example of a method for obtaining a printed circuit board is to apply a conductive paste to one or both sides of the epoxy resin sheet using a known method such as screen printing or inkjet printing to form a wiring pattern. The conductive paste is preferably flexible and stretchable. By mounting various electronic elements on the aforementioned printed circuit board, it is possible to obtain a flexible device or a stretchable device.

[0056] <This laminate> An example of an embodiment of the present invention (referred to as "this laminate") is a laminate comprising a carrier sheet on at least one side of the epoxy resin sheet.

[0057] (Career Sheet) By laminating carrier sheets, the strength of the laminate is increased, making it easier to handle and allowing for repeated use. Furthermore, even if the epoxy resin sheet is viscous, the surface of the carrier sheet is not viscous, thus preventing it from sticking to machinery and slowing down the process.

[0058] The carrier sheet may be provided on one side or on both sides of the epoxy resin sheet. If the epoxy resin sheet has carrier sheets on both sides, they may be made of the same material and thickness, or they may be made of different materials and thicknesses.

[0059] The average thickness of the carrier sheet is preferably 1 to 500 μm, and more preferably 5 μm or more or 300 μm or less, of which 10 μm or more or 150 μm or less, and of which 20 μm or more or 120 μm or less. The average thickness of the carrier sheet is determined by measuring the thickness at at least three points using a micrometer and taking the arithmetic mean of those measurements.

[0060] Examples of carrier sheets include thin sheets made from materials such as paper, resin, and metal. Paper and resin films are particularly preferred because they are inexpensive, easy to process, and easy to dispose of and recycle, with resin films being even more preferred in terms of transparency.

[0061] As for the paper, for example, high-quality paper, kraft paper, glassine paper, parchment paper, and supercalendered kraft paper, which have a silicone coating on the surface, can be used.

[0062] As resin films, for example, 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 can be used. The peel strength may be adjusted by applying a silicone resin release agent or the like to the surface of these films. Examples of thin, sheet-like materials made from metals include metal foils such as copper foil.

[0063] From an appearance standpoint, the carrier sheet is preferably a resin film mainly composed of polyester, a resin film mainly composed of polyimide, or copper foil. Furthermore, the term "main component resin" refers to the resin that makes up the largest proportion of the resins constituting the carrier sheet, specifically the resin that accounts for 50% by mass or more, of which 70% by mass or more, of which 80% by mass or more, and of which 90% by mass or more (including 100% by mass).

[0064] 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 it may be a copolymerized polyester obtained by further copolymerizing 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, and 1,4-cyclohexanedimethanol. On the other hand, dicarboxylic acids that can be used as other components of copolymerized polyesters 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, etc. Oxycarboxylic acids such as p-oxybenzoic acid can also be used.

[0065] 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.

[0066] The polyimide may be obtained by polymerizing a tetracarboxylic acid or aromatic tetracarboxylic anhydride with a diamine, and is preferably obtained by polymerizing an aromatic tetracarboxylic acid or aromatic tetracarboxylic dianhydride with an aromatic diamine and / or aliphatic diamine.

[0067] The aforementioned resin film may be either an unoriented film or an oriented film, but an oriented film is preferred from the viewpoint of mechanical strength, and a biaxially oriented film is more preferred. In addition, the resin film may be subjected to a surface treatment such as corona treatment or plasma treatment beforehand.

[0068] The carrier sheet may be a single-layer or multi-layer structure of two or more layers, as long as it does not exceed the scope of the present invention. Furthermore, the surface of the carrier sheet may be coated with a silicone resin release agent or the like to adjust its peel strength.

[0069] (Laminated structure) This laminate may have a carrier sheet on at least one side of the epoxy resin sheet, even if it has "other layers" between the epoxy resin sheet and the carrier sheet, even if it has "other layers" on the surface of the carrier sheet, or even if it has "other layers" on one side of the epoxy resin sheet opposite to one of the carrier sheets. Examples of these "other layers" include release layers, adhesive layers, bonding layers, hard coat layers, barrier layers, and so on. For example, the laminate may have a carrier sheet on at least one side of the epoxy resin sheet via a release layer.

[0070] (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 comes into contact with the epoxy resin sheet. By including a release layer in the carrier sheet, it becomes easier to adjust the peel strength between the epoxy resin sheet and the carrier sheet.

[0071] The components of the release layer are not particularly limited and may include silicone compounds, fluorine compounds, waxes, surfactants, etc. Silicone compounds are preferred due to their good balance of cost and release properties. Furthermore, a release control agent may be used in combination to adjust the release properties of the release layer.

[0072] For example, commercially available carrier sheets containing polyester film and a release layer include "Purex A31" from Teijin Film Solutions Limited and "MRF-38" and "MRF-75" from Mitsubishi Chemical Corporation.

[0073] (Manufacturing method) The method for manufacturing this laminate is not particularly limited. For example, the following methods for manufacturing a laminate comprising carrier sheets on both sides of the epoxy resin sheet can be described: Method 1 and Method 2.

[0074] One example of a manufacturing method is to apply an epoxy resin composition (a) onto a first carrier sheet, cure the epoxy resin composition (a) to form the epoxy resin sheet, and then bond a second carrier sheet to the side of the epoxy resin sheet opposite to the side with the first carrier sheet.

[0075] As a second manufacturing method, an epoxy resin composition (a) is applied to a first carrier sheet, a second carrier sheet is bonded to the side of the epoxy resin composition (a) opposite to the side with the first carrier sheet, and then the epoxy resin composition (a) is cured to form the epoxy resin sheet.

[0076] Alternatively, the epoxy resin sheet may be obtained by peeling the carrier sheet from the laminate. In other words, one method for manufacturing the epoxy resin sheet is to obtain it by peeling the carrier sheet from the laminate.

[0077] (Physical properties of this laminate) The tensile storage modulus of this laminate at 100°C to 200°C is 6.0 × 10⁻⁶. 7 ~1.0×10 10 It is preferable that it be Pa. A carrier sheet is laminated to at least one side of this epoxy resin sheet to form a laminate, and the tensile storage modulus of the laminate at 100°C to 200°C is set to 6.0 × 10⁻⁶. 7 ~1.0×10 10 By adjusting the Pa value, problems such as elongation, bending, and wrinkling of the epoxy resin sheet during secondary processing can be suppressed, improving handling. More specifically, by adjusting the tensile storage modulus of the laminate at 100°C to 200°C to the above range, even if the epoxy resin sheet is flexible, bending and wrinkling of the laminate are suppressed. Furthermore, when the laminate is punched, for example, it will not stick to the punching blade, and the dimensional stability of the punched-out parts will be good. In addition, if the tensile storage modulus of the laminate at 100°C to 200°C is below the above upper limit, it is easy to form the laminate into a roll shape, and even when it is unwound for secondary processing after being stored in a roll for a long period of time, it is possible to maintain the same shape (thickness variation, etc.) and various properties as when it was first manufactured. From this perspective, the tensile storage modulus of this laminate at 100°C to 200°C is 6.0 × 10⁻⁶. 7 ~1.0×10 10 It is preferable that it be Pa, and in particular 8.0 × 10 7 Pa or higher or 5.0 × 10 9 Below Pa, and among those, 1.0 × 10 8 The above or 1.0 × 10 9 It is even more preferable that it be Pa or less.

[0078] Furthermore, the tensile storage modulus at 100°C to 200°C is 6.0 × 10⁻⁶. 7 ~1.0×10 10 "Pa" refers to a tensile storage modulus of 6.0 × 10⁻¹⁰ over the entire temperature range of 100°C to 200°C. 7 In addition, 1.0 × 10 10 This means maintaining a value below Pa. The tensile storage modulus of the laminate can be measured specifically by the method described in the examples.

[0079] In this laminate, when the carrier sheet is peeled off from the epoxy resin sheet for use, the peel strength between the epoxy resin sheet and the carrier sheet is preferably 5N / 15mm or less, more preferably 3N / 15mm or less, and even more preferably 1N / 15mm or less. Because the peel strength is below the upper limit, when peeling the carrier sheet from the epoxy resin sheet, the epoxy resin sheet or laminate with excellent elasticity can be easily obtained without damaging the peel surface of the epoxy resin sheet.

[0080] Furthermore, this laminate can be configured to allow for easy peeling of the carrier sheet from the epoxy resin sheet, as described above, or it can be configured to prevent the carrier sheet from peeling off. To prevent peeling, an adhesive layer can be laminated between the epoxy resin sheet and the carrier sheet.

[0081] (thickness) The average thickness of this laminate is preferably 30 μm to 1000 μm, and more preferably 50 μm or more or 500 μm or less, of which 80 μm or more or 400 μm or less, and of which 100 μm or more or 350 μm or less. The average thickness of this laminate can be determined by measuring the thickness at at least three locations, for example using a micrometer, and taking the arithmetic mean of those measurements.

[0082] (Applications of this laminate) This laminate can be used for the same purposes as the epoxy resin sheet described above. Specifically, it can be suitably used as a release agent, cushioning material, or anti-slip material (sealing material) in the manufacturing processes of various molded products, particularly in press molding, vacuum molding, and pressure molding. Furthermore, this laminate can be suitably used as a carrier film for transporting workpieces, a protective film for protecting workpieces, and so on. Furthermore, this laminate can also be used as a component where flexibility is important, such as a flexible component or a stretchable component that incorporates the laminate.

[0083] <Main winding body> A wound body according to one embodiment of the present invention (referred to as "the wound body") has a structure in which a laminate, which is provided with a carrier sheet on at least one side of the epoxy resin sheet, is wound around a core.

[0084] Conventional epoxy resin sheets are too rigid, which can lead to problems such as wrinkles and cracks when forming them into a rolled body. In contrast, as mentioned above, this epoxy resin sheet is flexible and can be suitably formed into a rolled body. Furthermore, this laminate has a specific tensile storage modulus, resulting in good handling (no problems such as stretching, bending, or wrinkling) when unwinding and using the rolled body.

[0085] In this wound body, the variation rate of the thickness of the laminate is preferably 20% or less, more preferably 15% or less, even more preferably 10% or less, and even more preferably 5.0% or less. By keeping the thickness variation rate of the laminate to 20% or less, a uniform thickness is achieved, resulting in a wound material with suppressed thickness fluctuations. This makes it possible to manufacture flexible or stretchable laminates, etc., with high productivity. The smaller the thickness variation rate of the laminate, the better, with a lower limit of 0% or more.

[0086] The rate of variation in the thickness of the laminate in a wound body is maximized by the value calculated by the following formula. Here, the thickness of the laminate is obtained by measuring the thickness at five points at 2m intervals in the flow direction and at 10mm intervals in the width direction from the edge of the laminate. Thickness variation rate [%] = 100 × |(Maximum or minimum thickness of the laminate) - (Average thickness of the laminate)| / (Average thickness of the laminate)

[0087] (core) The core is a cylindrical winding core used for winding this laminate.

[0088] Examples of core materials include paper, resin-impregnated paper, acrylonitrile / butadiene / styrene copolymer (ABS resin), fiber-reinforced plastic (FRP), phenolic resin, and inorganic-containing resin. Adhesives may also be used for the core. In particular, the core material is preferably plastic, thermosetting resin, etc., from the viewpoint of having a low coefficient of thermal expansion, high rigidity, low swelling with respect to humidity, and excellent winding properties. When the core material is paper, coating its surface with resin or other materials makes it easier to obtain the desired properties. From the viewpoint of surface smoothness, the core is preferably a tube made of resin-impregnated paper.

[0089] The outer diameter of the core is preferably 10 mm or more and 2,000 mm or less, more preferably 15 mm or more or 1,900 mm or less, and even more preferably 20 mm or more or 1,700 mm or less. An outer diameter of 10 mm or more is preferable because the laminate is more susceptible to the quality of the core.

[0090] <Explanation of terms> In this invention, the term "film" also includes "sheets," and the term "sheet" also includes "film."

[0091] In this invention, when "X~Y" (where X and Y are any numbers) is written, unless otherwise specified, it means "X or greater and Y or less," and also includes the meaning of "preferably greater than X" or "preferably less than Y." Furthermore, when "X or greater" (where X is any number) is written, unless otherwise specified, it includes the meaning of "preferably greater than X," and when "Y or less" (where Y is any number) is written, unless otherwise specified, it also includes the meaning of "preferably less than Y." [Examples]

[0092] The present invention is further illustrated by the following embodiments. These embodiments are not intended to limit the present invention in any way. The various manufacturing conditions and evaluation results in the following embodiments are intended to represent preferred upper or lower limits in the embodiments of the present invention, and the preferred range may be defined by a combination of the aforementioned upper or lower limits and the values ​​of the following embodiments or between embodiments. In the following, "parts" all refer to "parts by mass".

[0093] [Various analysis, evaluation, and measurement methods] The methods for analyzing, evaluating, and measuring the various physical properties and characteristics described below are as follows:

[0094] (1) Tensile storage modulus, glass transition temperature According to the dynamic viscoelasticity measurement method described in JIS K 7244-4:1999, measurements were performed using a dynamic viscoelasticity measuring device (DVA-200, manufactured by IT Measurement Control Co., Ltd.) under the measurement conditions of a frequency of 1 Hz, a heating rate of 3 °C / min, and double-arm tensile mode, and the storage modulus E' at 100 °C, 150 °C, and 200 °C was determined. Furthermore, the temperature at which the peak of tanδ obtained from the loss modulus E'' / storage modulus E' is obtained was defined as the glass transition temperature (Tg).

[0095] (2) Peel strength between epoxy resin sheet (A) and carrier sheet (B) The laminates (samples) prepared in the examples and comparative examples were cut into 15 mm wide x 250 mm long pieces to form test specimens. A T-type peel test was performed at the interface between the epoxy 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 with a displacement of 30 mm to 60 mm was defined as the peel strength.

[0096] (3) Peel strength between epoxy resin sheets (A) Two epoxy resin sheets (A) with the carrier sheet (B) removed were bonded together at their peel interfaces, pressed tightly with a hand roller, and then pressure-bonded at 0.1 MPa at 30°C. A T-type peel test was performed between the epoxy resin sheets (A) (A) in the same manner as in (2) above, and the average peel force between a displacement of 30 mm and 60 mm was defined as the peel strength.

[0097] (4) Hysteresis Loss The average value of hysteresis loss at 23°C was determined using the following method, which conforms to JIS K 7312:1996. A tensile testing machine (Shimadzu Corporation AG-1kNXplus) was used as the measuring device. The epoxy resin sheet (A), obtained by peeling the carrier sheet (B) from the laminate (sample) prepared in the Examples and Comparative Examples, was cut into pieces measuring 10 mm in width and 100 mm in length and used as the test specimen. A stress-strain curve was obtained from a tensile cycle test consisting of one cycle in which the specimen was chucked at both ends along its length with a chuck distance of 50 mm, raised to a strain of 50% at a crosshead speed of 300 mm / min, held for 2 seconds, and then lowered back to the initial position at the same speed. The stress-strain curve took the profile shown in Figure 1. The hysteresis loss was calculated from the obtained stress-strain curve using the following formula, with the difference between the area A1 of the curve obtained during the upward movement (the area enclosed by abcda in Figure 1) and the area A2 of the curve obtained during the downward movement (the area enclosed by abcef in Figure 1). The test was performed three times, and the average value was calculated. Hysteresis loss = (A2 / A1) × 100

[0098] (5) Thickness The thickness of the epoxy resin sheet (A) was set to a reference thickness (0 μm) equal to the thickness of two carrier sheets (B) using a micrometer. For an A4-sized laminated sample, the thickness was measured at three points 100 mm apart in the width direction from the edge, and the average value was calculated. Furthermore, the thickness of the laminate was determined by adding the thickness of the epoxy resin sheet (A) and the thickness of the two carrier sheets (B) as determined above.

[0099] (6) Resilience after stretching On an epoxy resin sheet (A) measuring 10 mm in width and 150 mm in length, markings were drawn along the length of the sheet with an initial distance L1 = 100 mm between the score points. Under ambient temperature of 23°C, an epoxy resin sheet (A) was set in a tensile testing machine with a gauge-to-gauge distance of 100 mm (same as the distance between chucks), and stretched to 120% (displacement distance: 20 mm) at a tensile speed of 200 mm / min. After holding the stretched state for 1 minute, the tensile load was released, and the gauge-to-gauge distance L2 was measured at 1 minute and 5 minutes after release. The recovery rate (%) was calculated using the following formula. Recovery rate (%) = ((120-L2) / (120-L1)) × 100

[0100] The recovery rate after 1 minute and 5 minutes following the release of the tensile load was evaluated according to the following criteria. ○ (very good): 99% or higher at both 1 minute and 5 minutes. △ (good): Both the 1-minute and 5-minute mark show 98% or higher, while one of them shows less than 99%. × (poor): Less than 98% at either 1 minute or 5 minutes.

[0101] (7) Tackiness evaluation The following method was used to evaluate the tackiness of the sheet to determine whether it was suitable for the process. Two epoxy resin sheets (A), measuring 15 mm wide x 100 mm long, were layered and bonded together using a hand roller. After heating at 50°C for 1 minute, they were peeled off by hand under 30°C conditions. The results were evaluated according to the following criteria. ○ (good): Wrinkle-free and easily peelable. △(usual): Slight stretching, peelable. × (poor): Sheet breakage or excessive stretching makes peeling difficult.

[0102] In the examples and comparative examples, epoxy resin sheets (A) and laminates were prepared as follows.

[0103] <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. In a 1 L glass flask equipped with a stirrer, dropping funnel, and thermometer, 141.8 parts by mass of 1,6-hexanediol and 0.51 parts by mass of ethyl boron trifluoride, preheated to 45°C, were charged and heated to 80°C. 244.3 parts by mass of epichlorohydrin were added dropwise over time, ensuring the temperature did not exceed 85°C. The mixture was aged for 1 hour at 80-85°C, then cooled to 45°C. 528.0 parts by mass of 22% by mass sodium hydroxide aqueous solution were added, and the mixture was vigorously stirred at 45°C for 4 hours. After cooling to room temperature, the aqueous phase was separated and removed. The mixture was then 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 in an Oldashaw distillation column (15 stages), and the fraction obtained at a pressure of 1300 Pa and a temperature of 170-190°C was selected as the main fraction, yielding 127.6 parts by mass of 1,6-hexanediol diglycidyl ether with a diglycidyl purity of 97% by mass, a total chlorine content of 0.15% by mass, and an epoxy equivalent of 116 g / equivalent, as determined by gas chromatography. 100 parts by mass of 1,6-hexanediol diglycidyl ether, 69.3 parts by mass of bisphenol F (phenolic hydroxyl group equivalent: 100 g / equivalent), and 0.13 parts by mass of ethyltriphenylphosphonium iodide (30% by mass methyl cellosolve solution) were placed in a pressure-resistant reaction vessel, and a polymerization reaction was carried out at 165-170°C for 5 hours under a nitrogen gas atmosphere to obtain a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether with an epoxy equivalent of 1,000 g / equivalent and a number average molecular weight of 3,000.

[0104] (Aliphatic epoxy resin (β1)) Polytetramethylene glycol diglycidyl ether (epoxy equivalent: 440 g / equivalent) was used as the aliphatic epoxy resin (β1).

[0105] (Hardening 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.

[0106] (filling material) As a filler, we used fumed silica "EVONIK Aerosil RX200".

[0107] <urethane sheet> As the urethane sheet, we used an 80μm thick urethane sheet made of polyurethane elastomer laminated sheet (product name "Silklon SES85-NW / PP") manufactured by Okura Industries Co., Ltd.

[0108] <Career Sheet (B)> A PET film (Mitsubishi Chemical Corporation, release-coated PET film "MRF75", 75 μm thick; film containing polyester film and release layer) was used as the carrier sheet (B1). As the carrier sheet (B2), a PE / PET film (a two-part film made by laminating a 50 μm thick low-density polyethylene film with a 50 μm thick biaxially oriented polyethylene elephthalate film) was used.

[0109] [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 described above. The epoxy resin composition was applied to the release layer of the first carrier sheet (B1), and the second carrier sheet (B1) was laminated and bonded using two hot rolls with adjusted clearance to achieve 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 (sample) consisting of carrier sheet (B1) / epoxy resin sheet (A) / carrier sheet (B1).

[0110] [Example 2] A laminate (sample) was prepared in the same manner as in Example 1, except that the epoxy resin composition was prepared by blending 67 parts by mass of epoxy resin (α1), 33 parts by mass of aliphatic epoxy resin (β1), 13 parts by mass of alicyclic polyamine, and 5 parts by mass of filler as described above.

[0111] [Example 3] A laminate (sample) was prepared in the same manner as in Example 1, except that the epoxy resin composition was prepared by blending 75 parts by mass of epoxy resin (α1), 25 parts by mass of aliphatic epoxy resin (β1), 11.7 parts by mass of alicyclic polyamine, and 5 parts by mass of filler.

[0112] [Example 4] An epoxy resin composition was prepared by blending 90 parts by mass of epoxy resin (α1), 10 parts by mass of epoxy resin (β1), and 9.77 parts by mass of alicyclic polyamine as described above. A laminate (sample) was then prepared in the same manner as in Example 1, except that carrier sheet (B2) was used instead of carrier sheet (B1).

[0113] [Comparative Example 1] A laminate (sample) was prepared in the same manner as in Example 1, except that an epoxy resin composition was prepared by blending 100 parts by mass of epoxy resin (α1) and 8.5 parts by mass of alicyclic polyamine as described above.

[0114] [Comparative Example 2] A urethane sheet was bonded onto the release layer of the first carrier sheet (B1), and then the second carrier sheet (B1) was bonded onto the urethane sheet to create a laminate (sample).

[0115] [Table 1]

[0116] In the above examples, the epoxy resin sheet obtained from a resin composition combining polytetramethylene glycol diglycidyl ether as an aliphatic epoxy resin (β) and an epoxy resin (α) having a block structure of rigid and flexible components exhibited low hysteresis loss and high resilience. Furthermore, it was found that the epoxy resin sheet of the examples had appropriate peel strength between sheets and exhibited suitable tackiness for use as a process sheet. The added aliphatic epoxy resin (β) is compatible with epoxy resin (α), and hydrogen bonding between aliphatic epoxy resin (β) and epoxy resin (α) restricts the highly mobile free ends in epoxy resin (α), thereby suppressing energy loss when subjected to stress, and consequently improving resilience. Considering this mechanism, it is thought that any epoxy resin containing aliphatic ether units that is compatible with epoxy resin (α) will exhibit the same effect as the polytetramethylene glycol diglycidyl ether described above.

Claims

1. The hysteresis loss after maintaining a 50% elongation in tensile mode for 2 seconds, as measured in accordance with JIS K 7312:1996, is 40% or less, and the epoxy resin composition containing the epoxy resin and curing agent is cured into a cured product. The epoxy resin composition comprises an epoxy resin (α) and an aliphatic epoxy resin (β). The epoxy resin (α) is an epoxy resin sheet comprising a unit containing any ring structure selected from the group consisting of a benzene ring, a naphthalene ring, anthracene ring, a pyrene ring, a biphenol ring, a cardo structure, a fluorene ring, a pyrrole ring, and a thiophene ring, and a unit containing any aliphatic hydrocarbon group selected from the group consisting of an alkylene group having 1 to 8 carbon atoms, an ethylene glycol group, a propylene glycol group, and a butylene glycol group.

2. The tensile storage modulus at 100-200°C is 1.0 × 10⁻⁶. ４ ~6.0 x 10 ７ The epoxy resin sheet according to claim 1, wherein the material is Pa.

3. The epoxy resin sheet according to claim 1 or 2, wherein the peel strength between the sheets is in the range of 0.05 to 2.5 N / 15 mm.

4. An epoxy resin sheet according to any one of claims 1 to 3, wherein the glass transition temperature is 20°C or lower.

5. An epoxy resin sheet according to any one of claims 1 to 4, wherein the average thickness is 10 to 500 μm.

6. The epoxy resin sheet according to any one of claims 1 to 5, wherein the curing agent is an alicyclic polyamine.

7. The epoxy resin sheet according to any one of claims 1 to 6, wherein the aliphatic epoxy resin (β) is an epoxy resin having aliphatic ether units.

8. The epoxy resin sheet according to any one of claims 1 to 7, wherein the aliphatic epoxy resin (β) is a polyalkylene glycol diglycidyl ether.

9. The epoxy resin sheet according to any one of claims 1 to 8, wherein the epoxy resin (α) is an epoxy resin having bisphenol F units and alkyldiol diglycidyl ether units.

10. An epoxy resin sheet according to any one of claims 1 to 9, used as a release agent, a cushioning material, and an anti-slip material.

11. A stretchable member comprising an epoxy resin sheet according to any one of claims 1 to 9.

12. A flexible member comprising an epoxy resin sheet according to any one of claims 1 to 9.

13. A laminate comprising a carrier sheet on at least one side of an epoxy resin sheet according to any one of claims 1 to 9.

14. A laminate comprising a carrier sheet on at least one side of an epoxy resin sheet according to any one of claims 1 to 9, with a release layer in between.

15. The tensile storage modulus at 100-200°C is 6.0 × 10⁻⁶. ７ ~1.0 x 10 １０ The laminate according to claim 13 or 14, wherein the material is Pa.

16. The laminate according to any one of claims 13 to 15, wherein the carrier sheet is a polyester film, a polyimide film, and a copper foil.

17. A laminate according to any one of claims 13 to 16, used as a release agent, a cushioning material, and an anti-slip material.

18. A stretchable member comprising a laminate according to any one of claims 13 to 17.

19. A flexible member comprising a laminate according to any one of claims 13 to 17.

20. 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, The hysteresis loss of the epoxy resin sheet after maintaining a 50% elongation in tensile mode for 2 seconds, as measured in accordance with JIS K 7312:1996, is 40% or less, and the epoxy resin sheet is made of a cured product obtained by curing an epoxy resin composition containing epoxy resin and a curing agent. The epoxy resin composition comprises an epoxy resin (α) and an aliphatic epoxy resin (β). The epoxy resin (α) is a wound body comprising a unit containing any ring structure selected from the group consisting of a benzene ring, a naphthalene ring, anthracene ring, a pyrene ring, a biphenol ring, a cardo structure, a fluorene ring, a pyrrole ring, and a thiophene ring, and a unit containing any aliphatic hydrocarbon group selected from the group consisting of an alkylene group having 1 to 8 carbon atoms, an ethylene glycol group, a propylene glycol group, and a butylene glycol group.

21. The coiled body according to claim 20, wherein the epoxy resin sheet is the epoxy resin sheet according to any one of claims 2 to 9.

Images