JP7363546B2 - Method for manufacturing laminate and epoxy resin sheet - Google Patents

Description

The present invention relates to a method for manufacturing a laminate and an epoxy resin sheet.

Epoxy resins are used in various fields because they have excellent heat resistance, adhesiveness, water resistance, mechanical strength, electrical properties, and the like. Particularly in the electrical/electronic field, in recent years, as electrical/electronic parts have become smaller, more precise, and have higher performance, the epoxy resins used have come to be required to have high moldability. Recently, there has been a demand for adaptability to applications where flexibility is more important, such as flexible laminates and stretchable laminates.

Patent Document 1 discloses a specific highly flexible epoxy resin, and a resin composition containing the epoxy resin is a cured product that has a good balance of adhesiveness and electrical properties while also having high flexibility. It is stated that it gives.

Japanese Patent Application Publication No. 2005-320477

When a highly flexible cured epoxy resin is formed into a thin film and formed into a single layer sheet, the single layer sheet has the advantage of being excellent in flexibility and stretchability.
However, since high flexibility and stretchability also mean low rigidity, the single-layer sheet has the aspect of poor handling properties.
Therefore, an object of the present invention is to provide a laminate containing an epoxy resin sheet with good flexibility and handling properties, and a method for manufacturing the epoxy resin sheet.

As a result of extensive studies, the inventors of the present invention discovered that the above-mentioned problems can be solved by using a laminate having a specific configuration, and have completed the present invention.

That is, the present invention relates to the following [1] to [14].
[1] A laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one side of the epoxy resin sheet (A),
The epoxy resin sheet (A) has a tensile storage modulus of 1.0×10 ⁴ to 6.0×10 ⁷ Pa at 100 to 200°C, and a maximum height Sz of the surface in contact with the carrier sheet (B). is 15000 nm or more,
A laminate in which the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) is 5N/15mm width or less.
[2] The laminate according to [1] above, wherein the epoxy resin sheet (A) has a tensile elongation of 100% or more.
[3] The laminate according to [1] or [2] above, wherein the epoxy resin sheet (A) has an arithmetic mean roughness Sa of 500 nm or more on the surface in contact with the carrier sheet (B).
[4] The laminate according to any one of [1] to [3] above, wherein the laminate has a tensile storage modulus of 6.0×10 ⁷ to 1.0×10 ¹⁰ Pa at 100° C. to 200° C. laminate.
[5] The laminate according to any one of [1] to [4] above, wherein the carrier sheet (B) includes a film whose main resin is polyester.
[6] The laminate according to any one of [1] to [5] above, wherein the carrier sheet (B) includes a release layer.
[7] The epoxy resin sheet (A) is made of a cured product obtained by curing an epoxy resin composition containing an epoxy resin and an alicyclic polyamine, according to any one of [1] to [6] above. laminate.
[8] The laminate according to [7] above, wherein the epoxy resin has a block structure of a rigid component and a flexible component.
[9] The laminate according to any one of [1] to [8] above, wherein the epoxy resin sheet (A) has a thickness of 10 to 500 μm.
[10] The laminate according to any one of [1] to [9] above, comprising the carrier sheet (B) on both sides of the epoxy resin sheet (A).
[11] A laminate obtained by peeling off the carrier sheet (B) from one side of the laminate according to [10] above.
[12] A flexible laminate or stretchable laminate using the epoxy resin sheet (A) of the laminate according to any one of [1] to [11] above.
[13] Production of an epoxy resin sheet, including the step of obtaining the epoxy resin sheet (A) by peeling the carrier sheet (B) from the laminate according to any one of [1] to [11] above. Method.
[14] A wound body in which a laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one side of the epoxy resin sheet (A) is wound around a core,
The epoxy resin sheet (A) has a tensile storage modulus of 1.0×10 ⁴ to 6.0×10 ⁷ Pa at 100 to 200°C, and a maximum height Sz of the surface in contact with the carrier sheet (B). is 15000 nm or more,
A wound body in which the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) is 5N/15mm width or less.

According to the laminate of the present invention, an epoxy resin sheet having good flexibility and handling properties can be obtained.

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

<Summary of the present invention>
The laminate of the present invention comprises an epoxy resin sheet (A) and a carrier sheet (B) on at least one side of the epoxy resin sheet (A), and the epoxy resin sheet (A) is The storage elastic modulus is 1.0×10 ⁴ to 6.0×10 ⁷ Pa, the maximum height Sz of the surface in contact with the carrier sheet (B) is 15000 nm or more, and the epoxy resin sheet (A) and the The peel strength with the carrier sheet (B) is 5 N/15 mm width or less.

In the laminate of the present invention, by providing a carrier sheet (B) on at least one side of the epoxy resin sheet (A), when a continuous secondary processing process such as Roll to Roll is performed, the epoxy resin sheet (A) can be prevented from elongating, bending, wrinkles, etc.

The epoxy resin sheet (A) of the present invention has a tensile storage modulus of 1.0×10 ⁴ to 6.0×10 ⁷ Pa at 100 to 200°C. On the other hand, the tensile storage modulus of a typical epoxy resin sheet at 100 to 200°C is about 0.1 GPa to 10 GPa.
Therefore, the epoxy resin sheet (A) to which the present invention is directed is much more flexible than general epoxy resin sheets, and can be positioned as a special epoxy resin sheet.

Epoxy resin sheets have a highly polar sheet surface, so the sheet surface has high tackiness and the sheets tend to stick together. In addition, since the epoxy resin sheet (A) of the present invention has high flexibility as described above, it is more likely to have handling problems than general epoxy resin sheets.
Therefore, in the laminate of the present invention, by setting the maximum height Sz of the surface of the epoxy resin sheet (A) in contact with the carrier sheet (B) to be 15,000 nm or more, the epoxy resin sheets (A) will stick to each other and will not peel off. can be prevented, and handling properties are improved.

Further, in the laminate of the present invention, the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) is 5 N/15 mm width or less, so that the carrier sheet (B) can be peeled off from the epoxy resin sheet (A). In this case, an epoxy resin sheet or a laminate having excellent elasticity can be easily obtained without tearing or chipping the peeled surface of the epoxy resin sheet (A).

Therefore, according to the present invention, all of the handling properties during secondary processing, the handling properties of the epoxy resin sheet itself, and the handling properties when peeling the carrier sheet (B) from the epoxy resin sheet (A) are good. Become.

Hereinafter, details of the epoxy resin sheet (A) and carrier sheet (B) included in the laminate of the present invention will be described.

<Epoxy resin sheet (A)>
1. Physical Properties In the present invention, the epoxy resin sheet (A) has a tensile storage modulus of 1.0×10 ⁴ to 6.0×10 ⁷ Pa at 100 to 200° C., and is a sheet with excellent elasticity.
Note that "tensile storage modulus of 1.0×10 ⁴ to 6.0×10 ⁷ Pa at 100 to 200°C" means that the tensile storage modulus is 1.0× in the entire temperature range of 100 to 200°C. This means maintaining a value of 10 ⁴ Pa or more and 6.0×10 ⁷ Pa or less. Cases of other numerical ranges shall be handled in the same manner.
In the present invention, the tensile storage modulus of the epoxy resin sheet (A) at 100 to 200° C. is preferably 6.0×10 ⁴ to 1.0×10 ⁷ Pa, more preferably 4.0×10 ⁵ ~9.0×10 ⁶ Pa.
The tensile storage modulus of the epoxy resin sheet (A) can be specifically measured by the method described in Examples.

In the present invention, the maximum height Sz of the surface of the epoxy resin sheet (A) in contact with the carrier sheet (B) is 15,000 nm or more, preferably 15,500 nm or more, and more preferably 16,000 nm or more. The upper limit value is preferably 50,000 nm or less.
When the maximum height Sz is within the above numerical range, it is possible to prevent the epoxy resin sheets (A) from sticking to each other and not being peeled off, resulting in good handling properties.
Specifically, the maximum height Sz of the epoxy resin sheet (A) can be measured by the method described in Examples.

In the present invention, the arithmetic mean roughness Sa of the surface of the epoxy resin sheet (A) in contact with the carrier sheet (B) is preferably 500 nm or more, more preferably 600 nm or more, and even more preferably 700 nm or more. The upper limit is preferably 5000 nm or less.
When the arithmetic mean roughness Sa is within the above-mentioned numerical range, it is possible to prevent the epoxy resin sheets (A) from sticking to each other and not peeling off, resulting in good handling properties.
The arithmetic mean roughness Sa of the epoxy resin sheet (A) can be specifically measured by the method described in Examples.

In the present invention, the tensile elongation of the epoxy resin sheet (A) is preferably 100% or more, more preferably 150% or more, still more preferably 200% or more, even more preferably 300% or more. . The upper limit is preferably 500% or less.
The tensile elongation of the epoxy resin sheet (A) can be specifically measured by the method described in Examples.

In the present invention, the thickness of the epoxy resin sheet (A) is preferably 10 to 500 μm, more preferably 20 to 400 μm, even more preferably 30 to 300 μm, even more preferably 50 to 200 μm. .
The thickness (average thickness) of the epoxy resin sheet (A) is measured with a micrometer and determined by the arithmetic mean of the measurements.

In the present invention, the peel strength between the epoxy resin sheets (A) is preferably 10 N/15 mm width or less, more preferably 9 N/15 mm width or less, and even more preferably 8 N/15 mm width or less. The lower limit is preferably 1N/15mm width or more.
When the peel strength is within the above numerical range, even if the epoxy resin sheets (A) stick together, they can be easily peeled off, resulting in good handling properties.
The peel strength between epoxy resin sheets (A) can be specifically measured by the method described in Examples.

2. Form of Epoxy Resin Sheet (A) In the present invention, the epoxy resin sheet (A) is a sheet-like molded body made of a cured product of an epoxy resin composition. "Curing" here means intentionally curing the epoxy resin in the epoxy resin composition by heat and/or light, etc. For example, the epoxy resin sheet (A) before curing is cured for a long period of time. This also includes cases where the material gradually hardens due to the effects of heat and light over time when stored in a room.

Note that in this specification, the term "epoxy resin" refers to both the raw material resin before curing and the resin after curing (cured product). Since the epoxy group is consumed by the curing reaction, the resin after curing may not have an epoxy group (epoxy structure), but these will not be distinguished in this specification.

Hereinafter, the epoxy resin composition (hereinafter also referred to as "epoxy resin composition (a)") suitably used in the present invention will be explained in detail. However, the epoxy resin composition used in the present invention is not limited to the following epoxy resin composition (a).

(1) Epoxy resin composition (a)
The epoxy resin composition (a) contains at least an epoxy resin and a curing agent, and can contain a solvent and other components as necessary.
Hereinafter, the epoxy resin, curing agent, solvent, and other components will be explained in detail.

(1-1) Epoxy resin In the present invention, the epoxy resin composition (a) includes an epoxy resin having a block structure of a rigid component and a flexible component (hereinafter referred to as "epoxy resin (α)"). It is preferable to contain.
The rigid component is a structure containing many aromatic ring structures, such as a fused aromatic ring structure such as a benzene ring, a naphthalene ring, an anthracene ring, or a pyrene ring, or an aromatic ring structure such as a biphenol ring, a cardo structure, or a fluorene ring. , a pyrrole ring, a thiophene ring, and the like.
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, or a butylene glycol group.
By including such an epoxy resin (α), flexibility can be imparted to the cured product.

Note that 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, the epoxy resin (α) only needs to have an epoxy group or a structure derived from an epoxy group in at least one of the rigid component and the flexible component. From the viewpoint of imparting flexibility while retaining the inherent properties of epoxy resins such as heat resistance and mechanical strength, it is desirable to have only one of the rigid component and the flexible component contain an epoxy group or a structure derived from an epoxy group. It is preferable that you do so.

Specific epoxy resins (α) include, for example, a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether, a copolymer of 1,6-hexanediol and bisphenol F diglycidyl ether, a copolymer of bisphenol F and Copolymer with 1,4-butanediol diglycidyl ether, copolymer with 1,4-butanediol and bisphenol F diglycidyl ether, copolymer with bisphenol A and 1,6-hexanediol diglycidyl ether , a copolymer 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, copolymer of tetramethylbiphenol and 1,6-hexanediol diglycidyl ether, copolymer of 1,6-hexanediol and tetramethylbiphenol diglycidyl ether, tetramethylbiphenol and 1,4 - copolymer with butanediol diglycidyl ether, copolymer with 1,4-butanediol and tetramethylbiphenol diglycidyl ether, copolymer with biphenol and 1,6-hexanediol diglycidyl ether, 1, Copolymer of 6-hexanediol and biphenol diglycidyl ether, copolymer of biphenol and 1,4-butanediol diglycidyl ether, copolymer of 1,4-butanediol and biphenol diglycidyl ether, 1 , a copolymer of 4-naphthalenediol and 1,6-hexanediol diglycidyl ether, a copolymer of 1,6-hexanediol and 1,4-naphthalenediol diglycidyl ether, a copolymer of 1,4-naphthalenediol and Copolymer of 1,4-butanediol diglycidyl ether, copolymer of 1,4-butanediol and 1,4-naphthalenediol diglycidyl ether, 1,6-naphthalenediol and 1,6-hexanediol Copolymer with diglycidyl ether, copolymer with 1,6-hexanediol and 1,6-naphthalenediol diglycidyl ether, copolymer with 1,6-naphthalenediol and 1,4-butanediol diglycidyl ether Examples include polymers, copolymers of 1,4-butanediol and 1,6-naphthalenediol diglycidyl ether, and the like.
One type of these may be used alone, or two or more types may be used as a mixture in any combination and ratio. Among these, from the viewpoint of flexibility, the epoxy resin (α) preferably contains a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether.

Moreover, in the present invention, the epoxy resin composition (a) may contain an epoxy resin other than the above-mentioned epoxy resin (α) (hereinafter referred to as "epoxy resin (β)") as the epoxy resin.
Examples of the epoxy resin (β) include glycidyl ether type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, and cresol novolac type epoxy resin. , glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, linear aliphatic epoxy resins, alicyclic epoxy resins, and heterocyclic epoxy resins.
One type of these may be used alone, or two or more types may be used as a mixture in any combination and ratio.

The epoxy resin composition (a) may be one containing only epoxy resin (α), one containing epoxy resin (α) and epoxy resin (β), or one containing only epoxy resin (β). It may be.

When the epoxy resin composition (a) contains an epoxy resin (α) and an epoxy resin (β), the proportion of the epoxy resin (β) in the total epoxy components as solid content in the epoxy resin composition is: Preferably it is 5% by mass or more, more preferably 10% by mass or more. The upper limit is preferably 95% by mass or less, more preferably 90% by mass or less.
When the proportion of the epoxy resin (β) is at least the above lower limit, the effect of improving the physical properties by blending the epoxy resin (β) can be sufficiently obtained. On the other hand, when the proportion of the epoxy resin (β) is equal to or less than the above upper limit, the effect of improving flexibility and flexibility due to the epoxy resin (α) can be sufficiently obtained.

In the present invention, "solid content" means components excluding the solvent, and includes not only solid epoxy resins or epoxy compounds, but also semi-solids and viscous liquids.
Moreover, "all epoxy components" means the total of the epoxy resin (α) and the above-mentioned epoxy resin (β).

(1-2) Curing agent The curing agent used in the present invention is one that contributes to the crosslinking reaction between the epoxy group of the epoxy resin and a group that is reactive with the epoxy group. There are no particular restrictions on the curing agent, and all commonly known epoxy resin curing agents 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-based curing agents, isocyanate-based curing agents, blocked isocyanate-based curing agents, and the like.
One type of these may be used alone, or two or more types may be used as a mixture in any combination and ratio. Among these, the curing agent having an alicyclic structure is preferable from the viewpoint of high transparency and less coloring.

The curing agent having an alicyclic structure may be any substance as long as it has an alicyclic structure and contributes to the crosslinking reaction and/or chain lengthening reaction between the epoxy groups of the epoxy resin.
Specific examples include alicyclic polyamines, alicyclic acid anhydrides, and the like.
More specifically, the alicyclic polyamines include 1,4-diazabicyclo-2,2,2-octane, 1,8-diazabicyclo-5,4,0-undec-7-ene, N,N'- Dimethylpiperazine, N-aminoethylpiperazine, menthendiamine, isophoronediamine, hexamethylenetetramine, methylenebiscyclohexanamine, 1,3-bisaminomethylcyclohexane, norbornenediamine, 1,2-diaminocyclohexane, and alicyclics thereof Examples include modified alicyclic polyamines obtained by epoxy modification, ethylene oxide modification, dimer acid modification, Mannich modification, Michael addition, thiourea condensation, and ketimine modification of the formula polyamine. Examples of the alicyclic acid anhydride include hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and the like.
Among these, alicyclic polyamines are preferred, and among these, isophoronediamine, hexamethylenetetramine, methylenebiscyclohexanamine, 1,3-bisaminomethylcyclohexane, norbornenediamine, 1,2-diaminocyclohexane, and modified products thereof are preferred. Particularly preferred.

Commercially available curing agents having an alicyclic structure can also be used, such as "jER Cure 113" and "jER Cure ST-14" manufactured by Mitsubishi Chemical Corporation, and "Rikacid MH-700" manufactured by Shin Nippon Chemical Co., Ltd. can be used.

The content of the curing agent in the epoxy resin composition (a) (if a curing agent other than the curing agent having an alicyclic structure is used, the content of the curing agent having an alicyclic structure and the other curing agent) content) is preferably 0.1 to 100 parts by mass, more preferably 80 parts by mass or less, even more preferably 60 parts by mass or less, particularly preferably 40 parts by mass, based on 100 parts by mass of all epoxy components. It is as follows.

(1-3) Solvent The epoxy resin composition (a) may be diluted with a solvent in order to appropriately adjust the viscosity of the epoxy resin composition during handling such as during coating film formation. In the epoxy resin composition (a), the solvent is used to ensure ease of handling and workability in molding the epoxy resin composition, and there is no particular restriction on the amount used.
In the present invention, the terms "solvent" and "solvent" are used separately depending on their usage, but the same or different types may be used independently.

Examples of the solvent 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, and methanol. , ethanol, etc., and these solvents can also be used as a mixed solvent of two or more kinds as appropriate.

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

For example, an inorganic filler is blended into the epoxy resin composition (a) to improve various properties such as the effect of lowering the curing shrinkage rate and the effect of lowering the coefficient of thermal expansion of the resulting cured product. It can be applied to the electronic field, especially to liquid semiconductor encapsulating materials. Organic fillers such as rubber particles and acrylic particles may also be included to impart toughness.

Inorganic fillers that can be used include powdered reinforcing agents and fillers, such as 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, others, kaolin, mica, quartz powder, graphite, carbon black, carbon nanotubes, molybdenum disulfide, boron nitride, Examples include aluminum nitride.
When adding an inorganic filler, it is necessary to ensure the tensile storage modulus of the epoxy resin sheet (A) within the above range. The amount of these inorganic fillers added is preferably 900 parts by mass or less based on 100 parts by mass of the total epoxy components and curing agent. The lower limit is not particularly limited, but is preferably 1.0 parts by mass or more.

Furthermore, it is also possible to incorporate fibrous reinforcing agents and fillers. Examples include glass fiber, ceramic fiber, carbon fiber, alumina fiber, silicon carbide fiber, boron fiber, aramid fiber, cellulose nanofiber, and cellulose nanocrystal.
Further, cloth or nonwoven fabric made of organic fibers or inorganic fibers can also be used.

These inorganic fillers, fibers, cloths, and non-woven fabrics may also be surface treated with a silane coupling agent, titanate coupling agent, aluminate coupling agent, or primer. can.

Furthermore, the epoxy resin composition (a) may optionally contain a coupling agent, a plasticizer, a diluent, a flexibilizing agent, a dispersant, a wetting agent, a coloring agent, a pigment, an ultraviolet absorber, a hindered amine-based A light stabilizer such as a light stabilizer, an antioxidant, a defoaming agent, a mold release agent, a flow control agent, etc. may be added.
The blending amount of these components is preferably 20 parts by mass or less per 100 parts by mass of the sum of the epoxy resin and the curing agent. The lower limit is not particularly limited, but is preferably 0.1 part by mass or more.

Furthermore, various curable monomers, oligomers, and synthetic resins may be added to the epoxy resin composition (a) as necessary for the purpose of improving the properties of the resin in the final coating film.
For example, one or a combination of two or more of cyanate ester resins, acrylic resins, silicone resins, polyester resins, etc. can be used.
The blending 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 based on 100 parts by mass of the sum of the epoxy resin and the curing agent. The lower limit is not particularly limited, but is preferably 1.0 parts by mass or more.

(2) Preferred Embodiment The epoxy resin sheet (A) of the present invention is preferably made of a cured product of an epoxy resin composition (a) containing an epoxy resin and an alicyclic polyamine, and includes bisphenol F and 1, It is more preferable to use a cured product obtained by curing an epoxy resin composition (a) containing a copolymer with 6-hexanediol diglycidyl ether and an alicyclic polyamine.

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

2. Form of Carrier Sheet (B) (1) Base Material In the present invention, examples of the base material of the carrier sheet (B) include thin sheet-like materials made from paper, resin, metal, or the like.
In particular, sheets such as paper and resin films are preferred because they are inexpensive, easy to process, and easy to dispose of and recycle, and resin films are more preferred from the viewpoint of transparency.

As the paper, for example, those whose surfaces are coated with silicone can be used, such as high quality paper, kraft paper, glassine paper, parchment paper, and super calendered kraft paper.

As the resin film, for example, a film whose main component is a polyolefin such as polyethylene or polypropylene, a polyester such as polyethylene terephthalate or polyethylene naphthalate, a polyimide, or a polycarbonate can be used.
Further, from the viewpoint of appearance, ease of processing, durability, heat resistance, cost, etc., it is preferable that the carrier sheet (B) includes a resin film containing polyester as a main resin. As long as the gist of the present invention is not exceeded, the resin film may have a single layer structure or a multilayer structure of two or more layers.
In addition, "main component resin" means the resin with the highest content among the resins constituting the base material, specifically 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass. The above refers to a resin that preferably accounts for 90% by mass or more (including 100% by mass).

The polyester is preferably one obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic glycol. The polyester may be a polyester consisting of one type of aromatic dicarboxylic acid and one type of aliphatic glycol, or may be a copolymerized polyester obtained by further copolymerizing one or more other components.
Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalene dicarboxylic acid, and examples of aliphatic glycols include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol.
Typical polyesters include polyethylene terephthalate obtained by polycondensing terephthalic acid and ethylene glycol, polyethylene naphthalate obtained by polycondensing 2,6-naphthalene dicarboxylic acid and ethylene glycol, and the like.
On the other hand, dicarboxylic acids used as other components of the copolymerized polyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalene dicarboxylic acid, and sebacic acid, and glycol components include ethylene glycol, diethylene glycol, and propylene glycol. , butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like. Oxycarboxylic acids such as p-oxybenzoic acid can also be used.

The resin film may be a non-stretched film or a stretched film. Among these, a stretched film is preferred from the viewpoint of mechanical strength, and a biaxially stretched film is more preferred. Further, the resin film may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

Further, the carrier sheet (B) is preferably provided with surface irregularities for the purpose of adjusting the maximum height Sz of the epoxy resin sheet (A) and, if necessary, the arithmetic surface roughness Sa.
There are various methods for providing surface irregularities on the base material of the carrier sheet (B), such as methods using mechanical processing such as sandblasting, and adding particles such as inorganic fillers and organic fillers. can be used.
In addition, when providing a layer having surface irregularities on the base material of the carrier sheet (B), in addition to the above method, a method of providing a release layer containing particles such as an inorganic filler or an organic filler on the base material, A method of providing an uneven layer on a base material containing two or more types of polymers that form a phase-separated structure, a method of forming an uneven layer by providing a layer mainly composed of polyethylene, etc. on the base material, and embossing the layer. Various methods such as a method for providing surface irregularities can also be used as a method for providing surface irregularities.

(2) Release layer The carrier sheet (B) can be provided with a release layer on the surface of the base material. By providing the release layer, the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) can be lowered.
Examples of the main components of the release layer include, in addition to silicone resins, non-silicone resins such as alkyd resins, olefin resins, acrylic resins, long-chain alkyl group-containing compounds, and rubber. The release layer may contain one or more of these as a main component.
Note that the main component of the release layer means a component that imparts releasability to the release layer.
Further, the release layer may further contain other components such as a crosslinking agent and a catalyst.

(Silicone resin)
Examples of the silicone resin include solvent-type and solvent-free types. Since solvent-based silicone resins are diluted with a solvent to form a coating solution, they can be used in a wide variety of applications, from high molecular weight (that is, high viscosity) polymers to low viscosity low molecular weight polymers (oligomers). Therefore, compared to the solvent-free type, it is easier to control releasability and it is easier to design according to the required performance (quality).
Examples of the silicone resin include addition reaction type, condensation reaction type, ultraviolet curing type, and electron beam curing type. Among these, addition reaction type silicone resins are preferred because they have high reactivity and excellent productivity, and compared with condensation reaction type silicone resins, they have advantages such as small change in peel force after production and no curing shrinkage.

The addition reaction type silicone resin is not particularly limited, and various types can be used. For example, those commonly used as conventional thermosetting addition reaction type silicone resin mold release agents can be used. Examples of this addition reaction type silicone resin include those having an alkenyl group such as a vinyl group or an electrophilic group such as a hydrosilyl group as a functional group in the molecule, which can be easily thermoset. , polydimethylsiloxane having such functional groups, polydimethylsiloxane in which part or all of the methyl groups are replaced with aromatic functional groups such as phenyl groups, etc. can be used.
Silica, silicone resin, antistatic agents, dyes, pigments, and other additives may be added to the silicone resin as necessary.

(Olefin resin)
As the olefin resin, a crystalline olefin resin can be used. As this crystalline olefin resin, polyethylene, crystalline polypropylene resin, etc. are preferable.
Examples of polyethylene include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. Examples of the crystalline polypropylene resin include propylene homopolymers having an isotactic structure or syndiotactic structure, propylene-α-olefin copolymers, and the like.
These crystalline olefin resins may be used alone or in combination of two or more.

(acrylic resin)
As the acrylic resin, an acrylic resin having a crosslinked structure can generally be used. The acrylic resin may be a modified product such as a long-chain alkyl-modified acrylic resin or a silicone-modified acrylic resin.

(Long-chain alkyl group-containing compound)
Examples of the long-chain alkyl group-containing compound include polyvinyl carbamate obtained by reacting a polyvinyl alcohol polymer with a long-chain alkyl isocyanate having 8 to 30 carbon atoms, and polyethyleneimine containing a long-chain alkyl isocyanate having 8 to 30 carbon atoms. Alkylurea derivatives obtained by reacting isocyanates, etc. can be used.

(rubber)
As the rubber, for example, natural rubber resins and synthetic rubber resins such as butadiene rubber, isoprene rubber, styrene-butadiene rubber, methyl methacrylate-butadiene rubber, acrylonitrile-butadiene rubber, etc. can be used.

(Crosslinking agent)
By containing a crosslinking agent in the release layer, the strength and wettability of the release layer are improved.
As the crosslinking agent, conventionally known materials can be used, such as oxazoline compounds, isocyanate compounds, epoxy compounds, melamine compounds, carbodiimide compounds, silane coupling compounds, hydrazide compounds, aziridine compounds, and the like. Among them, oxazoline compounds, isocyanate compounds, epoxy compounds, melamine compounds, carbodiimide compounds, and silane coupling compounds are preferred. In order to further strengthen the strength of the release layer, melamine compounds and oxazoline compounds are preferable, and in order to improve the adhesion to the base film, oxazoline compounds, isocyanate compounds, epoxy compounds, and carbodiimide compounds are preferable. Preferably, oxazoline compounds and isocyanate compounds are particularly preferable.

(catalyst)
By adding a catalyst to the mold release layer, the reaction of the mold release agent can be promoted.
The type of catalyst is not particularly limited, but when using an isocyanate as a crosslinking agent, it is preferable to use a curing catalyst in order to promote the reaction between the isocyanate and the reactive polyolefin.
When using isocyanate as a crosslinking agent, curing catalysts include tertiary amines, carboxylates of tertiary amines, carboxylic acid metal salts (potassium acetate, potassium octylate, stannath octoate, etc.), and organometallic compounds (dibutyltin, etc.). dilaurate, etc.), with tertiary amines being preferred.

Examples of tertiary amines include triethylenediamine, N-ethylmorpholine, N-methylpiperidine, pyrrolidine, quinuclidine, 1,4-diazabicyclo[2.2.2]octane, diethylethanolamine, N,N,N',N '-Tetramethylhexamethylene diamine, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1,8-diazabicyclo-[5.4.0]-7-undecene or its carboxylate salt, and bis(dimethyl (aminoethyl) ether or its carboxylic acid salt, and two or more of these may be used in combination.

(3) Form example of carrier sheet (B) In the present invention, by using, for example, the following carrier sheet (BI) or carrier sheet (B-II) as the carrier sheet (B), the epoxy resin sheet (A ) may be adjusted.

(3-1) Carrier sheet (BI)
The carrier sheet (BI) includes at least a base material and an uneven layer. Each layer will be explained in detail below.

[Base material]
As the base material of the carrier sheet (BI), sheets made from paper, resin, metal, etc. exemplified in (1) above can be used, and it is preferable to use a resin film. From the viewpoint of ease of processing, durability, heat resistance, cost, etc., a resin film containing polyester as the main resin is more preferable, and a resin film containing polyethylene terephthalate as the main resin is even more preferable.

When a resin film is used as the base material, it may contain particles for the purpose of imparting slipperiness and preventing scratches during the carrier sheet manufacturing process.
The type of particles is not particularly limited, but for example, inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, titanium oxide; acrylic resin, styrene resin, urea resin. , phenolic resin, epoxy resin, benzoguanamine resin and the like. These particles may be used alone or in combination of two or more.
Further, the shape of the particles is not particularly limited, but examples thereof include spherical, lumpy, rod-like, and flattened shapes.

The average particle size of the particles is preferably 5 μm or less, more preferably 3 μm or less. On the other hand, the lower limit of the average particle diameter of the particles is preferably 0.1 μm or more. By setting the average particle size within the above range, it is possible to give the carrier sheet (BI) an appropriate surface roughness and ensure good slipperiness and smoothness.
The average particle size can be determined by observing the cross section of the base material using a SEM, measuring the diameters of 10 or more particles, and using the average value. When the base material includes non-spherical particles, the average value of the longest diameter and the shortest diameter of the non-spherical particles may be taken as the diameter of each particle.

Further, the content of the particles is preferably 5% by mass or less, more preferably 3% by mass or less. On the other hand, the content of the particles is preferably 0.0003% by mass or more with respect to the lower limit. By setting the content of particles within the above range, slipperiness can be imparted to the carrier sheet (BI).

[Uneven layer]
The concavo-convex layer of the carrier sheet (BI) is a layer having a concavo-convex structure on its surface having convex portions and portions other than the convex portions (referred to as “concave portions”). Preferably, the uneven structure has a configuration in which the convex portions form an irregular shape when the surface thereof is viewed in plan.
Examples of the irregular shape include a sea-island structure that is naturally formed when incompatible polymers are mixed, a mesh shape with irregular convex portions, and irregular convex portions with non-uniform shapes. We can list the shapes that exist.

The uneven layer preferably contains, for example, two or more types of polymers, oligomers, or monomers (these are collectively referred to as "polymers, etc."), and is formed from a coating composition containing two or more types of polymers, etc. It is more preferable.
In this case, it is preferable to form the uneven layer by utilizing phase separation properties between different polymers. That is, the uneven layer preferably has a phase-separated structure made of two or more types of polymers.

In the uneven structure, an example can be given in which the composition forming the recesses and the composition forming the recesses are different from each other. For example, if component A accounts for a large proportion of the components that form the concave portions, and component B accounts for a large proportion of the components that form the convex portions, then component A and component B An example can be given where the values are different.

(Component A)
Component A, which accounts for the largest proportion of the components forming the recesses, is incompatible with component B, and from the viewpoint of forming mainly uneven recesses after coating, the solubility parameter (SP(A)) is preferably It is 8 or more and 21 or less, more preferably 10 or more or 20 or less, and still more preferably 12 or more or 19 or less.
In addition, from the viewpoint of improving the coating properties of the coating liquid, the weight average molecular weight (Mw) of component A is preferably 300 or more and 300,000 or less, more preferably 2,000 or more or 200,000 or less, and Preferably it is 5,000 or more or 100,000 or less.
Weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC).

Examples of the component A include acrylic polymers such as poly(meth)acrylate, polyesters, polyurethanes, polyolefins, polyethers, polystyrenes, polycarbonates, polyacrylonitrile, polyamides, polyimides, etc. It will be done. Among these, it is preferable to use poly(meth)acrylates from the viewpoint of easy adjustment of molecular weight and SP value and easy control of uneven shape. These components A may be used alone or in combination of two or more.

For example, if component A is an acrylic polymer, in order to increase its SP value, it is sufficient to design the acrylic polymer so that its side chain contains a large number of highly polar functional groups. Specifically, for example, homopolymers or copolymers containing structural units such as hydroxy (meth)acrylate having a hydroxyl group, (meth)acrylic acid having a carboxyl group, and glycidyl (meth)acrylate having a glycidyl group are used. can be mentioned.

In this specification, "(meth)acrylate" is a general term for acrylate and methacrylate, and means one or both of acrylate and methacrylate. "(Meth)acrylic" is a general term for acrylic and methacrylic, and means one or both of acrylic and methacrylic. (Meth)acrylic acid is a general term for acrylic acid and methacrylic acid, and means one or both of these. "(Meth)acryloyl group" is a general term for acryloyl group and methacryloyl group, and means one or both of them.

(Component B)
On the other hand, component B, which accounts for the largest proportion of the components forming the convex portions, is incompatible with component A, and from the viewpoint of forming mainly uneven convex portions after coating, the solubility parameter of component B ( SP(B)) is preferably 7 or more and 20 or less, more preferably 8 or more or 18 or less, still more preferably 9 or more and 17 or less.
The solubility parameter (SP(B)) of component B is preferably 0.01 or more and 10 or less lower than the solubility parameter (SP(A)) of component A, more preferably 0.05 or more or 7 or less lower, More preferably, it is lower than 0.1 or lower than 4.
Note that the solubility parameter of component B (SP(B)) may be higher than the solubility parameter of component A (SP(A)) by 0.01 or more and 10 or less.
Furthermore, if the uneven layer is formed of three or more types of polymers and at least one of component A and component B is formed of two or more types of polymers, any combination of them has the above relationship. All you have to do is do it. The same applies to the weight average molecular weight described below.

From the viewpoint of improving the coating properties of the coating liquid, the weight average molecular weight (Mw) of component B is preferably 500 or more and 400,000 or less, more preferably 2,000 or more or 300,000 or less, and even more preferably 10,000 or more or 250,000 or less.
Further, the weight average molecular weight (Mw) of component B is preferably 1000 or more larger than the weight average molecular weight (Mw) of component A.

Component B, which mainly forms the convex portions, can sufficiently withstand the drying temperature when forming the uneven structure and has a glass transition temperature of preferably 40° C. or higher, more preferably 50° C. from the viewpoint of retaining the shape. The temperature is more preferably 60°C or higher.

Examples of the component B include acrylic polymers such as poly(meth)acrylate, polyesters, polyurethanes, polyolefins, polyethers, polystyrenes, polycarbonates, polyacrylonitrile, polyamides, polyimides, etc. Among them, poly(meth)acrylates are preferred from the viewpoint of easy adjustment of molecular weight and SP value and easy control of uneven shape. These components B may be used alone or in combination of two or more.

For example, when component B is an acrylic polymer, in order to lower its SP value, for example, in the acrylic polymer, the SP value is Just choose the one with the lowest value. Specifically, for example, structures such as alkyl (meth)acrylates having an aliphatic hydrocarbon group, cycloalkyl (meth)acrylates having an alicyclic hydrocarbon group, and phenylalkyl (meth)acrylates having an aromatic hydrocarbon group. Mention may be made of homopolymers or copolymers containing the unit.

Note that the solubility parameter (SP value) is a solubility parameter and serves as a measure of solubility. The larger the solubility parameter value, the higher the polarity, and conversely, the smaller the value, the lower the polarity.
The SP value can be measured by a method such as a turbidity method or a Fedors estimation method.

In the uneven layer, both the concave portions and the convex portions, especially the convex portions, are preferably crosslinked, that is, have a crosslinked structure, in order to maintain the shape and improve heat resistance and solvent resistance.
Whether or not it has a crosslinked structure can be determined by measuring the gel fraction of each site and confirming that the value is greater than 0%, particularly 5% or more, especially 10% or more.

In this case, at least one of the two or more types of polymers, etc. is a thermoplastic resin having a crosslinkable structure, a curable resin composition, or a curable resin containing a thermoplastic resin having a crosslinkable structure. Preferably, it is a composition. In these cases, by crosslinking or curing the uneven layer, the uneven layer contains a cured product, and can improve heat resistance and solvent resistance.
Here, the cured product means a cured product of the thermoplastic resin or curable resin composition having a crosslinkable structure.
Further, a crosslinkable structure refers to a structure that has the property of crosslinking, and a crosslinked structure refers to a structure formed by crosslinking.

The method for introducing a crosslinkable structure into a thermoplastic resin is not particularly limited. For example, a method of introducing a crosslinkable structure into component A, component B, or other thermoplastic resins may be mentioned.
At this time, the crosslinkable structure is not particularly limited. For example, crosslinkable unsaturated bonds such as carbon-carbon double bonds, functional groups capable of chemical bonding, such as hydroxyl groups, carboxyl groups, amino groups, isocyanate groups, glycidyl groups, oxazoline groups, acid anhydride groups, aldehyde groups , mercapto group, epoxy group, carbodiimide group, etc. The crosslinkable structure exemplified above can be introduced into component A, component B, or other thermoplastic resins by copolymerization or polymer reaction.
Note that the crosslinked structure is not limited to covalent bonds, but also includes pseudo-crosslinks such as ionic bonds, coordinate bonds, and hydrogen bonds.

Examples of the curable resin composition include two-component curable resin compositions, room temperature curable resin compositions, photocurable resin compositions, and thermosetting resin compositions. A photocurable resin composition or a thermosetting resin composition that cures (crosslinks) by reacting with the resin is preferred.

The cured product of the curable resin composition may constitute component A or component B itself, or the curable resin composition may be used as a component other than component A and component B that form the uneven layer. When component A or component B itself is a curable resin composition, the monomers constituting these components are used as raw materials for the uneven layer, and the uneven structure is formed by forming component A or component B through a curing reaction. be able to.

Examples of the photo- or thermosetting resin composition include photocurable compositions containing a photocrosslinkable compound and a photocrosslinking initiator, thermosetting resin compositions, and the like.
Examples of the photocrosslinkable compound include compounds having a crosslinkable unsaturated bond, specifically monomers or oligomers having an ethylenically unsaturated bond.
As a photocrosslinking initiator, for example, when applying ultraviolet irradiation as an active energy ray,
Photocrosslinking initiators such as benzoin, acetophenone, thioxanthone, phosphine oxide, and peroxide can be used.
Examples of the thermosetting resin include urethane resin, urea resin, melamine resin, acrylic resin, and transparent polyimide precursor varnish.

To summarize the above, the formation method of forming an uneven layer in which two or more types of polymers contribute, for example, can be classified into the following formation examples. However, it is not limited to these combinations. Furthermore, the following description does not exclude the inclusion of additional optional components other than component A and component B.
(a) An uneven layer is formed using two or more types of thermoplastic polymers.
(b) Two or more types of thermoplastic polymers and a crosslinking agent are used as raw materials, and the uneven layer is formed by curing the crosslinking agent.
(c) Among the two or more types of thermoplastic polymers, at least one type of thermoplastic polymer has a crosslinkable structure, and the uneven layer is formed by crosslinking the crosslinkable structure.
(d) Among the two or more types of thermoplastic polymers, at least one type of thermoplastic polymer has a crosslinkable structure, and for a raw material containing a crosslinking agent, the crosslinkable structure and the crosslinking agent are combined. An uneven layer is formed by crosslinking and curing between the layers.
(e) One or more thermoplastic polymers, a polymerizable monomer, and a crosslinking agent are used as raw materials, and the uneven layer is formed by polymerizing and curing the polymerizable monomer and crosslinking agent.
(f) At least one type of polymer has a crosslinkable structure, and for a raw material containing a polymerizable monomer and a crosslinking agent, polymerization and Forms an uneven layer by crosslinking and curing.
(g) At least two or more of the above (a) to (f) are used in combination.

(Peeling component)
The uneven layer may contain a release component having release properties. When the polymer or the like forming the uneven structure has releasability, the polymer or the like serves as a releasable component.
In addition, when a component having release properties is added as an additive, the additive becomes the release component.
Specific examples of the component having releasability include silicone compounds, fluorine compounds, olefin compounds, long-chain alkyl group-containing compounds, and one or more of these compounds. Can be used. These may be polymers or the like or may be low molecular weight compounds.

The content of the release component in the uneven layer is preferably 0.5% by mass or more and 90% by mass or less, more preferably 1.0% by mass or more or 85% by mass or less, still more preferably 2.0% by mass or more or 80% by mass or less. % by mass or less.

[Release layer]
The carrier sheet (BI) can further reduce the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) by further laminating a release layer on the surface of the uneven layer.
However, it is not always necessary to provide a release layer on the outer surface of the uneven layer. For example, when the uneven layer contains the release component, as long as the release property is sufficient, there is no need to further provide the release layer. On the other hand, even if the uneven layer contains the release component, if the releasability is not sufficient, a release layer may be further laminated on the surface of the uneven layer.

The release layer of the carrier sheet (B-I) mainly contains non-silicone resins such as alkyd resins, olefin resins, acrylic resins, compounds containing long-chain alkyl groups, and rubber, in addition to the silicone resins exemplified in (2) above. Among them, it is preferable to use silicone resin as the main component from the viewpoint of easy control of releasability, and the release layer is difficult to migrate to the surface of the epoxy resin sheet (A). It is preferable that the main component is an olefin resin.

(3-2) Carrier sheet (B-II)
The carrier sheet (B-II) includes at least a substrate containing particles.

[Base material]
As the base material of the carrier sheet (B-(II)), sheets made from paper, resin, metal, etc. exemplified in (1) above can be used, and it is preferable to use a resin film. From the viewpoint of ease of processing, durability, heat resistance, cost, etc., a resin film containing polyester as the main resin is more preferable, and a resin film containing polyethylene terephthalate as the main resin is even more preferable.

The base material preferably has particles having an average particle size of 2.0 μm or more, more preferably 3.0 μm or more, and still more preferably 4.0 μm or more. The upper limit of the average particle diameter of the particles is preferably 10.0 μm or less, more preferably 9.0 μm or less, and still more preferably 8.0 μm or less. When the particle size is within the above range, the surface of the substrate can be roughened while improving productivity, and a matte-like substrate can be obtained.

The type of particles is not particularly limited, but includes, for example, inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, titanium oxide; acrylic resin, styrene resin, urea resin. , organic particles such as phenolic resin, epoxy resin, benzoguanamine resin; divinylbenzene, styrene, acrylic acid, methacrylic acid, mono or copolymer of vinyl monomers of acrylic acid or methacrylic acid, polytetrafluoroethylene, benzoguanamine resin, heat Examples include crosslinked polymer particles such as cured epoxy resins, unsaturated polyester resins, thermosetting urea resins, and thermosetting phenolic resins. These particles may be used alone or in combination of two or more.
Further, the shape of the particles may be, for example, spherical, lumpy, rod-like, flat, etc., and spherical is preferable because it allows a uniform matte surface to be obtained.

The content of the particles is preferably 20% by mass or less, more preferably 18% by mass or less, still more preferably 15% by mass or less, even more preferably 10% by mass or less. On the other hand, the content of the particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 2% by mass or more, even more preferably 3% by mass or more with respect to the lower limit. By setting the content of particles within the above range, the surface of the carrier sheet (B-II) can be suitably roughened, and breakage etc. are less likely to occur during film stretching.

[Release layer]
In the carrier sheet (B-II), a release layer can be provided on the surface of the base material. By providing the release layer, the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) can be lowered.

The release layer of the carrier sheet (B-II) mainly contains non-silicone resins such as alkyd resins, olefin resins, acrylic resins, compounds containing long-chain alkyl groups, and rubber, in addition to the silicone resins exemplified in (2) above. Among them, it is preferable to use silicone resin as the main component from the viewpoint of easy control of releasability, and the release layer is difficult to migrate to the surface of the epoxy resin sheet (A). It is preferable that the main component is an olefin resin.

(4) Other layers In addition to the base material, uneven layer, and release layer exemplified above, the carrier sheet (B) may include layers with various functions (referred to as "functional layers") as necessary. Can be done. The functional layer may be provided on only one side of the base material, or may be provided on both sides of the base material.
Examples of the functional layer include an easy-adhesion layer, an antistatic layer, an easy-sliding layer, a gas barrier layer for water vapor, etc., a layer to prevent precipitation of substances contained in the base material, an ultraviolet absorption layer, an anti-scratch layer, an antifouling layer, an antibacterial layer, Examples include an antireflection layer, a glossy layer, a matte layer, an ink-receiving layer, a colored layer, and a printing layer.

(5) Laminated structure The carrier sheet (B) may be used as a single layer of the base material, but if a layer other than the base material is provided, for example, a base material / uneven layer as in the carrier sheet (B-I). Alternatively, in addition to the structure of base material/uneven layer/release layer or the structure of base material/release layer as in the carrier sheet (B-II), functional layer/base material/uneven layer, base material/function Layer/uneven layer, functional layer/base material/mold release layer, base material/functional layer/mold release layer, functional layer/base material/functional layer/uneven layer, functional layer/base material/functional layer/mold release layer, Laminated configurations include functional layer/base material/uneven layer/mold release layer, base material/functional layer/uneven layer/mold release layer, functional layer/base material/functional layer/uneven layer/mold release layer, etc. .
However, the structure is not limited to these laminated structures, and it is also possible to add and laminate other layers as appropriate.

(6) Method for manufacturing carrier sheet (B) The carrier sheet (B) of the present invention can be manufactured, for example, as follows. Note that the method for manufacturing the carrier sheet (B) is not limited to the following method.

(6-1) An example of a method for manufacturing a carrier sheet (BI) An example of a method for manufacturing a carrier sheet (BI) will be described below.
The method for manufacturing the carrier sheet (BI) includes at least a first step of producing a base material, a second step of providing an uneven layer on the base material, and may further include a third step of providing a release layer.

(First step)
In the first step, a base material is produced, for example, by the following method.
First, a raw material for a resin film is prepared by a known method, supplied to a melt extrusion device, heated to a temperature equal to or higher than the melting point of the polymer, and melt-kneaded. The molten polymer is then directed through a multi-manifold or feedblock to a die.
Next, the molten sheet extruded from the die is rapidly cooled and solidified on a rotating cooling drum to a temperature below the glass transition temperature to obtain an unstretched sheet in a substantially amorphous state. In this case, in order to improve the flatness of the sheet, it is preferable to increase the adhesion between the sheet and the rotating cooling drum, and an electrostatic application adhesion method and/or a liquid application adhesion method are preferably employed.

The obtained unstretched sheet may be used as it is as a base material, but the unstretched sheet may be stretched in one direction using a roll or tenter type stretching machine and used as a base material.
When stretching an unstretched sheet, for example, the following method may be used. The stretching temperature is usually 70 to 150°C, preferably 80 to 140°C, and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, the film is stretched in a direction perpendicular to the first-stage stretching direction, usually at 70 to 170°C, and at a stretching ratio of usually 2.5 to 7 times, preferably 3.0 to 6 times. Subsequently, heat treatment is performed at a temperature of 180 to 270° C. under tension or relaxation within 30% to obtain a biaxially oriented film. In the above-mentioned stretching, a method of stretching in one direction in two or more stages can also be adopted. In that case, it is preferable to carry out the stretching so that the final stretching ratios in both directions fall within the above ranges.

After the above-mentioned heat treatment, it is preferable to relax the material by 2 to 20% in the longitudinal and/or transverse directions in the highest temperature zone of the heat treatment and/or in the cooling zone at the exit of the heat treatment. Moreover, it is also possible to add longitudinal re-stretching and re-transverse stretching as necessary.

(Second process)
In the second step, a concavo-convex layer is provided on the base material, for example, by the following method.
The method of providing the uneven layer on the base material is not particularly limited, but includes, for example, physical cutting, cutting by laser irradiation, transfer using a mold, photomasking used for resist materials, printing, interlayering between different polymers, etc. Examples include a method of forming a concave-convex layer by utilizing the phase separation property of . Among these, a method of forming an uneven layer by utilizing phase separation between different polymers is preferred.

When forming an uneven layer by utilizing phase separation between different polymers, the specific method is not limited as long as two or more types of polymers are used. Specifically, the following embodiments 1) to 5) can be mentioned. Further, a plurality of these methods may be combined.

1) Using two or more types of thermoplastic resins (polymers), an uneven structure is created by phase separation during the process of distilling off the solvent from a state dissolved in a solvent, or phase separation during the process of cooling and solidifying from a molten state. How to form.
2) A method in which a thermoplastic resin and a curable resin composition are mixed, and during the curing process of the curable resin composition, phase separation is caused by removing the thermoplastic polymer to form an uneven structure.
3) A curable resin composition is blended, and during the curing process of the curable resin composition, the curable resin composition that has become a polymer is expelled from the unreacted curable resin composition, forming protrusions. A method of forming an uneven structure by forming.
4) A method according to 1) above, in which at least one thermoplastic resin is made into a crosslinkable structure, and after forming an uneven structure by phase separation, a crosslinking reaction is performed to fix the uneven structure.
5) In 1) above, by mixing the curable resin composition with two or more thermoplastic resins, forming an uneven structure by phase separation of the thermoplastic resins, and then curing the curable resin composition. A method for fixing uneven structures.

In addition, when using a method that causes phase separation in the process of distilling off the solvent from a state dissolved in the solvent, as described below, two or more types of solvents are used in a mixture and the difference in solubility of the polymer etc. is used. A preferred method is to form a concavo-convex structure. If this method is adopted, a desired uneven structure can be formed simply by selecting a specific polymer or the like and a specific solvent. Therefore, the object of the present invention can be easily achieved without using a cutting device, a mold, or the like.

Hereinafter, a case in which a photocurable resin composition is used will be specifically described using the aspect (5) among the various aspects mentioned above as an example.
A mixed resin of component A, component B, and crosslinking initiator C if necessary is mixed with a predetermined mixed solvent Z, for example, a solvent that is a good solvent for component A, component B, and crosslinking initiator C. X and a solvent Y that is a good solvent for component A and crosslinking initiator C (that is, a cosolvent for them), a poor solvent for component B, and has a boiling point higher than that of solvent X. A curable coating composition is prepared by adding it to mixed solvent Z and dissolving it, and this curable coating composition is applied to the surface of a substrate. In the process of drying the mixed solvent Z, the solvent X volatilizes relatively quickly and the proportion occupied by the solvent Y increases, so that the component B, which is difficult to dissolve in the solvent Y, precipitates and forms convex portions. Further, upon drying, component A forms concave portions to form an uneven structure. Alternatively, the uneven structure may be formed by exciting and curing the crosslinking initiator C by, for example, irradiating it with light.

According to such a manufacturing method, it is possible to form a concavo-convex structure with convex portions having irregular shapes, and the selection of materials for component A, component B, crosslinking initiator C, and solvents X and Y is required. The size of the unevenness can be controlled by adjusting the blending amount.
However, the production method is not limited to this, and the crosslinking initiator C may be blended as necessary, and does not necessarily have to be blended.
Moreover, it is preferable that the solvent X and the solvent Y are mixed in the mixed solvent Z. However, it is not necessarily necessary to mix uniformly, and a suspension may be used.

In the above manufacturing method, the principle behind the formation of the uneven layer is that in the process of drying the curable coating composition after coating, the environment in the solvent changes as the mixed solvent Z decreases, and the phase changes. Component A and B, which are poorly soluble, undergo phase separation, and the component that is soluble in both solvents remains soluble in the solvent until it dries further, so Component B, which is poorly soluble in solvent Y, precipitates and forms mainly in convex areas. It is presumed that component A, which is soluble in both solvents, mainly forms the recesses and spontaneously forms the uneven structure.

The blending mass ratio of component A and component B is preferably 1:99 to 99:1, more preferably 5:95 to 95:5, and still more preferably 90:10 to 10:90.
In addition, when component A or component B consists of two or more types of components, the mass proportion is the sum of the two or more types of components.

(Crosslinking initiator C)
Examples of the crosslinking initiator C include photocrosslinking initiators, thermal crosslinking initiators, and the like. Among these, from the viewpoint of maintaining the uneven shape formed in the drying step, a curing system having fast curing properties is preferred, and from this viewpoint, a photocrosslinking initiator is preferred.

Examples of photocrosslinking initiators include 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-1-[4-(methylthio)phenyl] -2-morpholinopropan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1- Examples include butanone. These crosslinking initiators may be used alone or in combination of two or more. Among these, polyfunctional acrylates that are cured by ultraviolet light are preferred.

The amount of the crosslinking initiator is preferably 0.01 parts by mass or more and 20 parts by mass or less, more preferably 0.1 parts by mass or more or 10 parts by mass or less, based on 100 parts by mass of the total amount of components A and B. More preferably, it is 1 part by mass or more.

(Solvent X)
The solvent X is preferably a good solvent for component A, component B, and crosslinking initiator C. That is, it is preferable to use a solvent that can dissolve all of component A, component B, and crosslinking initiator C.

The boiling point of the solvent X is preferably 50°C or higher and 200°C or lower, more preferably 60°C or higher or 140°C or lower, and still more preferably 70°C or higher or 120°C or lower.

As the solvent Ether solvents such as ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate; methyl acetate, ethyl acetate, butyl acetate, methoxybutyl acetate, amyl acetate, propyl acetate, ethyl lactate, methyl lactate, Examples include organic solvents such as ester solvents such as butyl lactate; hydrocarbon solvents such as toluene, xylene, solvent naphtha, hexane, cyclohexane, ethylcyclohexane, methylcyclohexane, heptane, octane, and decane. These organic solvents may be used alone or in combination of two or more.

(Solvent Y)
The other solvent Y is preferably a good solvent for component A and crosslinking initiator C, and a poor solvent for component B. That is, it is preferable to use a solvent in which component A and crosslinking initiator C can be dissolved, but in which component B has low solubility.
Here, "low solubility of component B" includes cases where it is classified as insoluble or swelling with respect to component B.

The boiling point of the solvent Y is preferably 51°C or higher and 201°C or lower, more preferably 61°C or higher or 141°C or lower, and even more preferably 71°C or higher and 121°C or lower.
However, the boiling point of the solvent Y is preferably higher than the boiling point of the solvent X, more preferably 1° C. or more and 80° C. or less higher, and more preferably 2 ℃ or higher, more preferably 5℃ or higher.
By using a solvent with a higher boiling point than the solvent X as the solvent Y, the solvent X volatilizes earlier than the solvent Y, and component B that is difficult to dissolve in the solvent Y precipitates, thereby facilitating the formation of mainly convex portions.

Note that the solvent X and solvent Y to be used can be selected depending on the difference in boiling point. However, selection may be made based on differences in other characteristics. Specific properties include relative evaporation rate, vapor pressure at a given temperature and pressure, and affinity with component A or component B.
For example, from the same viewpoint, that is, from the viewpoint that solvent X can be volatilized earlier than solvent Y, the relative evaporation rate of solvent X is preferably higher than the relative evaporation rate of solvent Y. Among these, it is preferable that the relative evaporation rate of solvent Preferably it is less than the relative evaporation rate.
In this case, the "relative evaporation rate" is defined as the specific evaporation rate when the evaporation rate of butyl acetate at 25° C. and atmospheric pressure is set as 1. For example, the relative evaporation rates of various solvents are: butyl acetate: 1, MEK: 4.52, cyclohexane: 2.9, toluene: 2.66, methoxypropanol: 0.71, n-butanol: 0.39. .

Examples of the solvent Y include alcoholic solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and isobutanol; acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone diacetone alcohol, and the like. Ketone solvents; ether solvents such as ethylene glycol monomethyl ether and propylene glycol monomethyl ether; esters such as methyl acetate, ethyl acetate, butyl acetate, methoxybutyl acetate, amyl acetate, propyl acetate, ethyl lactate, methyl lactate, butyl lactate, etc. System solvents include hydrocarbon solvents such as toluene, xylene, solvent naphtha, hexane, cyclohexane, ethylcyclohexane, methylcyclohexane, heptane, octane, and decane, and water. These solvents may be used alone or in combination of two or more.

(Mixed solvent Z)
The mixed solvent Z is preferably a mixture of solvent X and solvent Y in a mass ratio of 0.1:99.9 to 99.9:0.1, more preferably 1:99 to 99:1, and 10 :90 to 90:10 is more preferable, even more preferably 15:85 to 85:15, particularly preferably 80:20 to 20:80.
In addition, when the solvent X or the solvent Y consists of two or more types of solvents, it is taken as the total mass proportion of each of the two or more types of solvents.

As a method for applying the above-mentioned curable coating composition to the surface of the substrate, known methods such as a kiss roll coater, bead coater, rod coater, Mayer bar coater, die coater, and gravure coater can be employed.

In addition, the drying temperature after applying the above-mentioned curable coating composition to the surface of the substrate is determined based on the boiling points of solvents X and Y in order to volatilize solvent X with priority over solvent Y after application. From this perspective, the temperature is preferably set at 10°C or higher and 150°C or lower, more preferably 20°C or higher or 140°C or lower, and even more preferably 40°C or higher or 125°C or lower. Note that it may be dried at room temperature.
By adjusting the heating (drying) temperature, the maximum height difference of the unevenness can be adjusted, and the lower the drying temperature, the larger the maximum height difference of the unevenness tends to be. Generally, solvents are volatile at temperatures below their boiling point, and their volatility characteristics vary depending not only on the boiling point but also on vapor pressure characteristics, affinity with polymers, etc. Therefore, the drying temperature may be set depending on the type of polymer used in the uneven layer, the blended mass ratio, the shape of the intended uneven structure, etc.

(Third step)
When the carrier sheet (BI) has a release layer, the release layer is provided on the uneven layer in the third step.
Examples of the method for providing the release layer include a method of applying a release layer composition to the uneven layer and then curing the release layer composition, and a method of laminating the release layer on the uneven layer.

Examples of methods for applying the release layer composition include air doctor coating, blade coating, rod coating, bar coating, knife coating, squeeze coating, impregnation coating, reverse roll coating, transfer roll coating, gravure coating, and kiss roll coating. Conventionally known coating methods such as coating, cast coating, spray coating, curtain coating, calendar coating, and extrusion coating can be used.

When heat treatment is performed to dry and harden the release layer composition, it is preferably performed at a temperature of 50 to 200°C. Note that it may be dried at room temperature.

In addition, active energy ray irradiation such as ultraviolet irradiation may be performed in order to cure the composition for a release layer.
In order to improve the applicability and adhesion of the coating solution that forms the release layer, the uneven layer is subjected to surface treatments such as chemical treatment, corona discharge treatment, plasma treatment, ozone treatment, chemical treatment, and solvent treatment before coating. Good too.

The method of laminating the release layer on the uneven layer may be a known method. In order to laminate the release layer on the uneven layer, an adhesive layer may be provided on the uneven layer, and the release layer may be laminated on the adhesive layer.

(6-2) An example of a method for producing a carrier sheet (B-II) The method for producing a carrier sheet (B-II) includes at least a first step of producing a base material containing particles, and further includes a release layer. It may also include a second step of providing.
The first step in the method for manufacturing the carrier sheet (B-II) is the same as in the carrier sheet (B-I) described in (6-1) above, except that the raw material for the resin film must contain particles. It may be the same as the first step. Further, the second step in the method for manufacturing the carrier sheet (B-II) may be the same as the third step in the method for manufacturing the carrier sheet (BI) described in (6-1) above.

(7) Preferred Embodiment The carrier sheet (B) of the present invention has a more preferable configuration in which a release layer is provided on the surface of the base material, and an uneven layer is provided on the surface of the base film, and a release layer is further provided on the surface of the uneven layer. A configuration in which layers are provided is more preferred. Moreover, it is preferable that the base material is a film containing polyester as a main resin.

<Laminated body>
The laminate of the present invention only needs to be provided with a carrier sheet (B) on at least one side of the epoxy resin sheet (A), and may be provided with the carrier sheet (B) on both sides of the epoxy resin sheet (A).
Further, layers other than the epoxy resin sheet (A) and the carrier sheet (B) may be included as long as the effects of the present invention are not impaired. Examples of layers other than the epoxy resin sheet (A) and the carrier sheet (B) include an adhesive layer, an adhesive layer, a hard coat layer, and a barrier layer.

When the epoxy resin sheet (A) is provided with carrier sheets (B) on both sides, the first carrier sheet (B1) is laminated on one side of the epoxy resin sheet (A), and the first carrier sheet (B1) is laminated on one side of the epoxy resin sheet (A). The second carrier sheet (B2) laminated on the other surface may be the same or different.
In this case, the epoxy resin sheet (A) may have a maximum height Sz of 15,000 nm or more on at least one of the surfaces in contact with the first carrier sheet (B1) and the surface in contact with the second carrier sheet (B2). Bye.

The laminate of the present invention has a peel strength between the epoxy resin sheet (A) and the carrier sheet (B) of 5 N/15 mm width or less, preferably 3 N/15 mm width or less, and more preferably 2 N/15 mm width or less. and more preferably 1N/15mm width or less. The lower limit is preferably 0.03N/15mm width or more.
Since the peel strength is within the above numerical range, when the carrier sheet (B) is peeled off from the epoxy resin sheet (A), the peeled surface of the epoxy resin sheet (A) does not tear or chip, and the elasticity is maintained. Epoxy resin sheets or laminates with excellent properties can be easily obtained.
In addition, when the carrier sheet (B) is provided on both sides of the epoxy resin sheet (A), the peel strength between the epoxy resin sheet (A) and the first carrier sheet (B1), and the peel strength between the epoxy resin sheet (A) and the first carrier sheet (B1) are It is sufficient that at least one of the peel strengths with the second carrier sheet (B2) is within the above numerical range.
That is, it is sufficient that at least one of the first carrier sheet (B1) and the second carrier sheet (B2) has been subjected to mold release treatment, and the other may be a general sheet that has not been subjected to mold release treatment.

The tensile storage modulus of the laminate of the present invention at 100 to 200°C is preferably 6.0×10 ⁷ to 1.0×10 ¹⁰ Pa, more preferably 6.0×10 ⁷ to 5.0× 10 ⁹ Pa, more preferably 1.0×10 ⁸ to 1.0×10 ⁹ Pa.
When the laminate has such a tensile storage modulus, it is possible to suppress problems such as elongation, bending, and wrinkles of the epoxy resin sheet, especially during secondary processing, and improve handling properties.
To explain in more detail, if the tensile storage modulus of the laminate at 100°C to 200°C is equal to or higher than the above lower limit, even if the epoxy resin sheet (A) is flexible, bending and wrinkles will be suppressed. Not only that, but also when punching a laminate, for example, the laminate does not stick to the punching blade, and the dimensional stability of the punched member is improved.
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 wound body (roll), and it can be kept in the rolled form for a long period of time. Even when it is fed out and subjected to secondary processing after being stored, it is possible to maintain the same shape (thickness variation, etc.) and various properties as at the time of manufacture.
The tensile storage modulus of the laminate can be specifically measured by the method described in Examples.

The laminate of the present invention has good deflection resistance (i.e., small change in deflection) by laminating the carrier sheet (B) on at least one side of the epoxy resin sheet (A) having a specific tensile storage modulus. It can be done. The amount of change in deflection of the laminate of the present invention is preferably 7.0 mm or less, more preferably 6.0 mm or less, and still more preferably 5.0 mm or less.
Specifically, the amount of change in deflection of the laminate can be measured by the method described in Examples.

The laminate of the present invention can have good elongation resistance by laminating a carrier sheet (B) on at least one side of an epoxy resin sheet (A) having a specific tensile storage modulus. The elongation rate of the laminate is preferably 20% or less, more preferably 10% or less, and still more preferably 5% or less.
Specifically, the elongation rate of the laminate can be measured by the method described in Examples.

The thickness of the laminate of the present invention is preferably 30 to 1000 μm, more preferably 50 to 500 μm, even more preferably 80 to 400 μm, even more preferably 100 to 350 μm.
The thickness (average thickness) of the laminate is measured with a micrometer and determined by their arithmetic mean.

<Method for manufacturing laminate>
Although the method for producing the laminate of the present invention is not particularly limited, a resin composition for an epoxy resin sheet (A) (hereinafter also referred to as "epoxy resin composition") is applied onto a carrier sheet (B), and the epoxy resin composition is It is preferable to include a step of curing the resin composition to form an epoxy resin sheet (A).
Moreover, when manufacturing a laminate including carrier sheets (B) on both sides of an epoxy resin sheet (A), the following manufacturing method 1 and manufacturing method 2 can be mentioned.
Manufacturing method 1: After applying an epoxy resin composition on the first carrier sheet (B1) and curing the epoxy resin composition to form an epoxy resin sheet (A), A method of attaching a second carrier sheet (B2) to a surface opposite to the surface on which the first carrier sheet (B1) is provided.
Manufacturing method 2: An epoxy resin composition is applied onto a first carrier sheet (B1), and a second A method of laminating a carrier sheet (B2) and then curing the epoxy resin composition to form an epoxy resin sheet (A).

The epoxy resin sheet (A) can be manufactured by curing an epoxy resin composition in a sheet-shaped state having a predetermined thickness. Alternatively, it can be manufactured by molding a semi-cured product obtained from an epoxy resin composition into a sheet having a predetermined thickness and further curing it.

The curing method for an epoxy resin composition varies depending on the components and amounts contained in the epoxy resin composition, and the shape of the compound (for example, the thickness of the sheet), but it is usually cured at 23 to 200°C for 5 minutes to 24 hours. Examples include heating conditions.
This heating is performed in two stages: primary heating at 20-160°C for 5 minutes to 24 hours, and secondary heating at 60-200°C, which is 40-180°C higher than the primary heating temperature, for 5 minutes to 24 hours. It is preferable. In order to reduce curing defects, a three-stage treatment may be performed in which tertiary heating is performed at 100 to 200° C. higher than the secondary heating temperature for 5 minutes to 24 hours.

When producing a cured product as a semi-cured product, the curing reaction of the epoxy resin composition may be allowed to proceed to such an extent that the shape can be maintained by heating or the like. When the epoxy resin composition contains a solvent, most of the solvent is removed by heating, reduced pressure, air drying, etc., but 5% by mass or less of the solvent may remain in the semi-cured product.
The epoxy resin sheet (A) of the present invention may be in a semi-cured state as long as the tensile storage modulus at 100 to 200° C. is within the above numerical range. If the epoxy resin sheet (A) is in a semi-cured state, it may be easier to form a wound body, or the secondary processability may be improved.

The laminate of the present invention is obtained by manufacturing a laminate having a carrier sheet (B) on both sides of an epoxy resin sheet (A), and then peeling off the carrier sheet (B) from at least one side of the obtained laminate. You can.
That is, the method for manufacturing a laminate in the present invention may include the step of peeling off the carrier sheet (B) from at least one side of the laminate.

Alternatively, the epoxy resin sheet (A) may be obtained by peeling off the carrier sheet (B) from the laminate of the present invention.
That is, the method for producing an epoxy resin sheet (A) in the present invention includes the step of obtaining an epoxy resin sheet (A) by peeling off the carrier sheet (B) from the laminate.

The epoxy resin sheet (A) or laminate obtained by the production method of the present invention can also be suitably used in applications where precision is required, such as in the electrical and electronic fields. For example, it can be used for flexible laminates or stretchable laminates where flexibility is important.

Examples of the flexible laminate or stretchable laminate include printed wiring boards on which metal foils such as copper foils are laminated.
As a method for producing a printed wiring board, for example, copper foil is layered on one or both sides of an epoxy resin sheet (A), hot press molding is performed using a vacuum press machine, etc. to produce a copper-clad laminate, and then etching processing is performed. A method of forming a wiring pattern and obtaining a printed wiring board is exemplified by the following.
Further, examples of the wiring pattern include a printed wiring board using conductive paste. An example is a method of applying a conductive paste to one or both sides of the epoxy resin sheet (A) by a known method such as a screen printing method or an inkjet printing method to form a wiring pattern and obtain a printed wiring board. . The conductive paste preferably has flexibility and stretchability.
By mounting various electronic elements on the printed wiring board, it is possible to obtain a flexible device or a stretchable device.

In addition, the epoxy resin sheet (A) or laminate of the present invention can also be used for electronic/electrical components such as cushioning materials, adhesive sheets, elastic tapes, and various sensor substrates including pressure sensors.
Adhesive sheets are used for image display panels such as liquid crystal displays (LCDs), plasma displays (PDPs), and electroluminescent displays (ELDs), as well as panels such as protective panels and touch panels that are placed on the front side (viewing side) when in use. It can be used as a filler that fills gaps between components.
In addition, various industrial cushioning materials, adhesive sheets, adhesive sheets, elastic tapes, sealing sheets, heat-resistant insulating sheets, heat-resistant conductive sheets, glass substitutes, protective films, including fields other than electronic and electrical components, It can also be applied to medical sheets, agricultural sheets, construction sheets, etc.

<Wound body>
The wound body of the present invention is a wound body in which a laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one side of the epoxy resin sheet (A) is wound around a core. The epoxy resin sheet (A) has a tensile storage modulus of 1.0×10 ⁴ to 6.0×10 ⁷ Pa at 100 to 200°C, and a maximum height of the surface in contact with the carrier sheet (B). The length Sz is 15000 nm or more, and the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) is 5 N/15 mm width or less.
Preferred embodiments are the same as those for the laminate of the present invention described above.

As mentioned above, the tensile storage modulus of a typical epoxy resin sheet at 100 to 200°C is about 0.1 GPa to 10 GPa, and the tensile elongation is about 10%. If it is too long, there is a risk that problems such as wrinkles and cracks may occur when forming the wound body in the first place. The wound body of the present invention can be suitably made into a wound body by using a flexible epoxy resin sheet (A).

In the wound body of the present invention, the length of the laminate is preferably 10 m or more, more preferably 20 m or more. When the length of the laminate is 10 m or more, for example, when used as a flexible laminate or a stretchable laminate, it is possible to continuously produce electronic components, and the continuous film forming property is excellent. Note that the upper limit of the length is not particularly limited, but is preferably 1000 m or less.

<Core>
The core is a cylindrical winding core used for winding the laminate.
Examples of the core material include paper, resin-impregnated paper, acrylonitrile/butadiene/styrene copolymer (ABS resin), fiber reinforced plastic (FRP), phenol resin, and inorganic-containing resin. An adhesive may be used for the core.

The material for the core is not particularly limited, but ABS resin, FRP, phenol resin, or inorganic-containing resin may be used from the viewpoint of having a small coefficient of thermal expansion, high rigidity, low swelling property against humidity, and excellent winding property. It is preferable to use ABS resin or FRP, which is lightweight and has little dust contamination.
When the material of the core is paper, desired characteristics can be easily obtained, especially 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 (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. A core width of 10 mm or more is particularly useful in this embodiment because the laminate is susceptible to the quality of the core.

EXAMPLES Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples. In addition, the values of various manufacturing conditions and evaluation results in the following examples have the meaning as preferable upper or lower limits in the embodiments of the present invention, and the preferable ranges are different from the above-mentioned upper or lower limits. , it may be a range defined by the values of the following examples or a combination of values of the examples. In the following, all "parts" indicate "parts by mass."

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

(1) Tensile Elongation The carrier sheet (B) was peeled off from the laminate sample, and the remaining epoxy resin sheet (A) was cut out to a width of 15 mm x length of 150 mm to prepare a test piece. According to JIS K7127, a tensile test was conducted on the test piece at a test speed of 200 mm/min in an environment of 23° C. and 50%, and the degree of elongation at tensile breakage was measured.

(2) Tensile storage modulus The dynamic viscoelasticity measurement method described in JIS K7244 was performed using a dynamic viscoelasticity measuring device (“DVA-200” manufactured by IT Instrumentation Control Co., Ltd.) at a frequency of 1 Hz and a heating rate of 3. Measurement was performed under the measurement conditions of .degree. C./min and double-sided tension mode, and the storage modulus E' at 100.degree. C., 150.degree. C., and 200.degree. C. was determined.

(3) Peel strength between epoxy resin sheet (A) and carrier sheet (B) The laminate sample was cut into a 15 mm wide x 250 mm long test piece using a universal material testing machine (Shimadzu Corporation's "AGS-X"). ), a T-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 average value of the peel force between displacements of 30 mm and 60 mm was determined as the peel strength. And so.

(4) Peel strength between epoxy resin sheets (A) The peeled interfaces of two epoxy resin sheets (A) from which the carrier sheet (B) has been peeled are pasted together, and after being brought into close contact with a hand roller, the peel strength is 0.1 MPa at 30°C. A T-peel test between the epoxy resin sheet (A) layers was performed on the sample bonded together under pressure in the same manner as in (3) above, and the average value of the peel force during a displacement of 30 mm to 60 mm was taken as the peel strength.
In addition, in the above test, those in which the epoxy resin sheet (A) was destroyed were judged to be "unmeasurable."

(5) Judgment of peel strength Based on the results of the peel tests in (3) and (4) above, evaluation was made according to the following criteria.
A (good): The epoxy resin sheet (A) can be peeled off from the epoxy resin sheet (A), and the peel strength between the epoxy resin sheets (A) is 10 N/15 mm or less B (poor): The epoxy resin sheet (A) and the epoxy resin sheet (A) cannot be peeled off, the epoxy resin sheet (A) and the carrier sheet (B) cannot be peeled off, and the interlayer peel strength between the epoxy resin sheets (A) exceeds 10 N/15 mm width. either

(6) Handling property Handling property was evaluated according to the following criteria.
A (good): Two 15 mm wide x 100 mm long epoxy resin sheets (A) were laminated together using a hand roller, heated at 50°C for 1 minute, and then peeled off by hand at 30°C. No wrinkles were observed. Can be easily peeled off.
B (poor): Two 15 mm wide x 100 mm long epoxy resin sheets (A) are laminated together using a hand roller, heated at 50°C for 1 minute, and then peeled off by hand at 30°C, resulting in sheet breakage. Or, peeling is difficult and wrinkles occur on the sheet.

(7) Deflection resistance <Fixed end dead weight deflection measurement>
The laminate sample was cut into a strip of width 25 mm x length 300 mm to form a test piece, and the portions up to 75 mm long on each side were placed on the edge of a horizontal desk. The part with a distance between gauge lines of 150 mm was left suspended in an environment of 24°C for 5 minutes, and the distance between the naturally bent end of the center part and the horizontal plane was measured. The distance between the center of the test piece and the fixed horizontal plane was defined as the amount of change in deflection, and the deflection resistance was evaluated as follows.
Note that a small value of the amount of change in deflection corresponds to suppressing curvature (warpage) of the punched laminate when the laminate is subjected to secondary processing such as punching, for example.
A: The absolute value of the amount of change in deflection is 0 mm or more and 5.0 mm or less. B: The absolute value of the amount of change in deflection is more than 5.0 mm and less than 7.0 mm. C: The absolute value of the amount of change in deflection is more than 7.0 mm.

(8) Elongation resistance The laminate sample was cut into a strip of width 12.5 mm x length 200 mm to prepare a test piece.
Using a tensile testing machine, the above sample was subjected to a tensile test at a distance between gauge lines of 100 mm and a test speed of 200 mm/min. The elongation rate of each sample was determined under a load of 50N. Elongation resistance was evaluated according to the following criteria.
Note that a low elongation value corresponds to good dimensional stability of the punched laminate when the laminate is subjected to secondary processing such as punching, for example.
A: Elongation rate is 0% or more and 2.0% or less B: Elongation rate is more than 2.0% and 20% or less C: Elongation rate is more than 20%

(9) Surface Roughness A white interference microscope "Contour GTX" (manufactured by Bruker) was used to measure the surface roughness Sa and Sz in the present invention. The laminate sample was cut out into 10 cm square pieces, the carrier sheet (B) was then peeled off, and the measurement was performed on the surface of the peeled side of the epoxy resin sheet (A) under the following conditions. Calculation was made from the results of image analysis.
Filter: White
Objective: 5×
FOVLens: 1.0×
Backscan length: 5
Scan length: 25

(10) Thickness The thickness of the epoxy resin sheet (A) is determined by peeling off the carrier sheet (B) from an A4 size laminate sample, and then peeling off the remaining epoxy resin sheet (A) from the edge at 100 mm intervals in the width direction. The thickness was determined by measuring the thickness at three locations using a micrometer, and rounding off the first integer digit of the average value.
Moreover, the thickness of the laminate was determined by calculating the sum of the thickness of the epoxy resin sheet (A) determined above and the thickness of the two carrier sheets (B).

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

<Materials used for epoxy resin sheet (A)>
(Epoxy resin (a))
As the epoxy resin (a), a copolymer of bisphenol F and 1,6-hexanediol diglycidyl ether prepared by the following method was used.
A 1 L glass flask equipped with a stirrer, a dropping funnel, and a thermometer was charged with 141.8 parts by mass of 1,6-hexanediol and 0.51 parts by mass of boron trifluoride ethyl ether, which had been preheated to 45°C, 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 aqueous sodium hydroxide solution was added thereto, and the mixture was vigorously stirred at 45°C for 4 hours. The mixture was cooled to room temperature, the aqueous phase was separated and 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 Oldashaw distillation column (15 stages), and by using the main fraction at a pressure of 1300 Pa and a temperature of 170 to 190°C, the crude 1,6-hexanediol diglycidyl ether was purified by gas chromatography. 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/eq were obtained.
100 parts by mass of the 1,6-hexanediol diglycidyl ether, 69.3 parts by mass of bisphenol F (phenolic hydroxyl group equivalent: 100 g/eq), 0.13 parts by mass of ethyltriphenylphosphonium iodide (30% by mass methyl cellosolve solution). The mixture was placed in a pressure-resistant reaction vessel and subjected to a polymerization reaction at 165 to 170°C for 5 hours under a nitrogen gas atmosphere to form bisphenol F with an epoxy equivalent of 1,000 g/eq and a number average molecular weight of 3,000. , 6-hexanediol diglycidyl ether was obtained.

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

<Materials used for carrier sheet (B)>
(Carrier sheet (1), (2))
Carrier sheets produced by the following methods were used as carrier sheets (1) and (2), respectively.

[Raw material for base material for carrier sheet]
- Polyester (A): Using terephthalic acid as the dicarboxylic acid component and ethylene glycol as the polyhydric alcohol component, a polyester (A) having an intrinsic viscosity of 0.65 dl/g was obtained by a conventional melt polymerization method.
- Polyester (B): Polyester (B) was obtained using the same method as polyester (A), except that 1% by mass of silica particles with an average particle diameter of 3.0 μm was added before melt polymerization.
- Polyester (C): Polyester (C) was obtained using the same method as polyester (A), except that 10% by mass of silica particles with an average particle diameter of 4.0 μm were added before melt polymerization.
The average particle diameter is measured by the sedimentation method based on Stokes' drag law using a centrifugal sedimentation type particle size distribution analyzer model SA-CP3 manufactured by Shimadzu Corporation. A value of 50% (based on volume) was used.

[Raw materials for coating liquid for easy adhesion layer]
60 parts by mass of a water-dispersed polycarbonate polyurethane resin (Tg: 35°C) having a carboxyl group, 30 parts by mass of a polymer-type crosslinking agent in which an oxazoline group is branched to an acrylic resin, a silica sol water dispersion (average particle size: 0 07 μm) was mixed to prepare a coating liquid for an easily bonding layer.

[Raw material of composition for uneven layer]
- Acrylic polymer A: Acrylic acid modified product obtained by copolymerizing glycidyl methacrylate, methyl methacrylate, and ethyl acrylate in a molar ratio of 98:1:1 (weight average molecular weight (Mw): 20,000, SP value: 12. 6, Tg: 32°C) was used.
- Acrylic polymer B: Copolymer formed by copolymerizing methyl methacrylate and methyl acrylate at a molar ratio of 99:1 (weight average molecular weight (Mw): 95,000, SP value: 9.9, Tg: 105 ° C. ) was used.
- Photopolymerizable compound: Dipentaerythritol hexaacrylate (weight average molecular weight: 578, SP value: 10.4) was used.
- Photocrosslinking initiator: Omnirad 127 manufactured by IGM Resin Co., Ltd. was used.
- Solvent X: Methyl ethyl ketone (a solvent capable of dissolving acrylic polymers A and B, with a boiling point of 80°C) was used.
- Solvent Y: Methoxypropanol (a solvent that dissolves acrylic polymer A but does not dissolve acrylic polymer B, and has a boiling point of 120°C) was used.

[Preparation of composition for uneven layer]
An acrylic polymer mixture containing 45 parts by mass of acrylic polymer A, 27.5 parts by mass of acrylic polymer B, 27.5 parts by mass of a photopolymerizable compound, and 5 parts by mass of a photocrosslinking initiator. A composition for an uneven layer having an acrylic polymer mixture concentration of 30% by mass was prepared by dissolving it in a mixed solvent Z obtained by mixing solvent X and solvent Y at a mass ratio of 72:28.

[Raw material of release layer composition]
- Ethylene-propylene copolymer: ethylene-propylene random copolymer ( ^1H -NMR composition mass ratio: ethylene/propylene = 74/26, MFR (230°C, load 2.16 kg) 2.0 g/10 minutes, A density of 0.86 g/cm ³ ) was used.
- Reactive polyolefin: Polytail H manufactured by Mitsubishi Chemical Corporation (hydride of polybutadiene having hydroxyl groups, number average molecular weight 2700, hydroxyl group content 1.5% by mass determined by NMR, density 0.85 g/cm ³ ) was used.
- Crosslinking agent: Takenate D160N (75% by mass ethyl acetate solution), which is an aliphatic trifunctional isocyanate/trimethylolpropane adduct manufactured by Mitsui Chemicals, was used.
- Curing catalyst: 1,4-diazabicyclo[2,2,2]octane manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. was used.

[Preparation of release layer composition]
A 2% by mass toluene solution was obtained by heating and dissolving the ethylene-propylene copolymer and the reactive polyolefin in toluene. Mix so that the solid content of the release layer composition is 95 parts by mass of ethylene-propylene copolymer, 3 parts by mass of reactive polyolefin, 1 part by mass of crosslinking agent, and 1 part by mass of curing catalyst. A release layer coating solution was prepared.

(Carrier sheet (1))
[Creation of base material for carrier sheet]
A mixed raw material obtained by mixing polyester (A) and (B) at a ratio of 95% and 5%, respectively, is used as a raw material for layer A, and polyester (A) is used as a raw material for layer B, and each is supplied to a separate melt extruder, After each is melted at 285°C, it is coextruded on a cooling roll set at 35°C in a layer configuration of 2 types and 3 layers (discharge rate of layer A/layer B/layer A = 5:40:5), and is cooled and solidified. An unstretched sheet was obtained.
Next, the film was stretched 3.0 times in the longitudinal direction at a film temperature of 85° C. using the difference in peripheral speed of the rolls, and then a coating solution for an easy-adhesion layer was applied to the surface of layer A of this longitudinally stretched film so that the film thickness after drying was 0. 05 μm, guided into a tenter, stretched 4.1 times in the transverse direction at 95°C, heat-treated at 235°C, and then relaxed by 2% in the transverse direction, forming layer A/layer B/layer A. A polyester film A having an adhesive layer of 5 μm/40 μm/5 μm/0.05 μm was obtained.

[Formation of uneven layer]
The composition for the uneven layer is applied to the surface of the easily adhesive layer of the polyester film A using a Mayer bar, and after volatilizing the solvent X and the solvent Y at 70 ° C., it is irradiated with ultraviolet rays using an ultraviolet irradiation device and photocured. Thus, a film with an uneven layer was produced, in which an uneven layer having an uneven structure on the surface was formed on one surface side of the base material.

[Formation of release layer]
The release layer coating solution is applied to the surface of the uneven layer of the film with an uneven layer using a Meyer bar, and heated to 150 ° C. to dry and cure, thereby providing a release layer with a film thickness of 0.2 μm. A carrier sheet (1) consisting of a release layer/irregular layer/adhesive layer/base material was prepared.

(Carrier sheet (2))
A mixed raw material prepared by mixing polyesters (A) and (C) at a ratio of 80% and 20%, respectively, is supplied to a melt extruder and melted at 285°C, then placed in a single layer on a cooling roll set at 35°C. The mixture was extruded and solidified by cooling to obtain an unstretched sheet.
Next, the film was stretched 3.0 times in the longitudinal direction at a film temperature of 85° C. using the difference in circumferential speed of the rolls, then introduced into a tenter, stretched 4.1 times in the transverse direction at 95° C., and heat treated at 235° C. Thereafter, the film was relaxed by 2% in the transverse direction to obtain a matte polyester film B having a thickness of 26 μm.
Thereafter, a release layer was coated on the matte polyester film B in the same manner as the carrier sheet (1) to produce a carrier sheet (2) consisting of the release layer/matte base material.

(Carrier sheet (3) to (6))
The following sheets were used as carrier sheets (3) to (6), respectively.
Carrier sheet (3): PETLSM100X (manufactured by Lintec Corporation, blasted release coated PET film, thickness 100 μm)
Carrier sheet (4): LDPE/PET film (two types of two-layer film made by laminating a 50 μm thick low density polyethylene (LDPE) film and a 50 μm thick biaxially stretched polyethylene terephthalate film)
Carrier sheet (5): KGM-8S Shiromaru D (manufactured by Lintec Corporation, release coated paper, thickness 100 μm)
Carrier sheet (6): Diafoil T100 (manufactured by Mitsubishi Chemical Corporation, uncoated PET film, thickness 100 μm)

<Example 1>
An epoxy resin composition was prepared by blending 8.5 parts by mass of a curing agent with 100 parts by mass of the epoxy resin (a). This epoxy resin composition is applied onto the release layer of the first carrier sheet (1), and the second carrier sheet (1 ) were laminated and pasted together, the resulting sample was subjected to a primary heat treatment at 40°C for 16 hours, and then a secondary heat treatment at 80°C for 6 hours to produce a laminate.

<Example 2>
A laminate was produced in the same manner as in Example 1, except that carrier sheet (B) used in Example 1 was replaced with carrier sheet (2).

<Example 3>
A laminate was produced in the same manner as in Example 1, except that the carrier sheet (B) used in Example 1 was replaced with carrier sheet (3).

<Comparative example 1>
A laminate was produced in the same manner as in Example 1, except that the carrier sheet (B) used in Example 1 was replaced with carrier sheet (4).

<Comparative example 2>
A laminate was produced in the same manner as in Example 1 except that the carrier sheet (B) used in Example 1 was replaced with carrier sheet (5).

<Comparative example 3>
A laminate was produced in the same manner as in Example 1 except that the carrier sheet (B) used in Example 1 was replaced with carrier sheet (6).

In the laminates of Examples 1 to 3, the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) was 5 N/15 mm width or less, and the peeled surface of the epoxy resin sheet (A) was not torn or chipped. It was found that the carrier sheet (B) could be peeled off from the epoxy resin sheet (A) without any trouble.
In addition, in the laminates of Examples 1 to 3, the maximum height Sz of the surface of the epoxy resin sheet (A) in contact with the carrier sheet (B) is 15000 nm or more, so that the peel strength between the epoxy resin sheets (A) can be improved. was 10 N/15 mm width or less, and even if the epoxy resin sheets (A) were stuck together, they could be easily peeled off, so it was found that the handling properties were good.
Furthermore, since the laminates of Examples 1 to 3 have excellent elongation resistance and deflection resistance, they have good handling properties during secondary processing (that is, defects such as wrinkles, elongation, and deflection are suppressed). I understand.

Claims (14)

A laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one side of the epoxy resin sheet (A),
The epoxy resin sheet (A) has a tensile storage modulus of 1.0×10 ⁴ to 6.0×10 ⁷ Pa at 100 to 200°C, and a maximum height Sz of the surface in contact with the carrier sheet (B). is 15000 nm or more,
A laminate in which the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) is 5N/15mm width or less. The laminate according to claim 1, wherein the epoxy resin sheet (A) has a tensile elongation of 100% or more. The laminate according to claim 1 or 2, wherein the epoxy resin sheet (A) has an arithmetic mean roughness Sa of 500 nm or more on a surface in contact with the carrier sheet (B). The laminate according to any one of claims 1 to 3, wherein the laminate has a tensile storage modulus of 6.0×10 ⁷ to 1.0×10 ¹⁰ Pa at 100 to 200°C. The laminate according to any one of claims 1 to 4, wherein the carrier sheet (B) includes a film whose main resin is polyester. The laminate according to any one of claims 1 to 5, wherein the carrier sheet (B) includes a release layer. The laminate according to any one of claims 1 to 6, wherein the epoxy resin sheet (A) is made of a cured product of an epoxy resin composition containing an epoxy resin and an alicyclic polyamine. The laminate according to claim 7, wherein the epoxy resin has a block structure of a rigid component and a flexible component. The laminate according to any one of claims 1 to 8, wherein the epoxy resin sheet (A) has a thickness of 10 to 500 μm. The laminate according to any one of claims 1 to 9, comprising the carrier sheet (B) on both sides of the epoxy resin sheet (A). A laminate obtained by peeling off the carrier sheet (B) from one side of the laminate according to claim 10. A flexible laminate or stretchable laminate using the epoxy resin sheet (A) of the laminate according to any one of claims 1 to 11. A method for producing an epoxy resin sheet, comprising the step of obtaining the epoxy resin sheet (A) by peeling off the carrier sheet (B) from the laminate according to any one of claims 1 to 11. A wound body in which a laminate comprising an epoxy resin sheet (A) and a carrier sheet (B) on at least one side of the epoxy resin sheet (A) is wound around a core,
The epoxy resin sheet (A) has a tensile storage modulus of 1.0×10 ⁴ to 6.0×10 ⁷ Pa at 100 to 200°C, and a maximum height Sz of the surface in contact with the carrier sheet (B). is 15000 nm or more,
A wound body in which the peel strength between the epoxy resin sheet (A) and the carrier sheet (B) is 5N/15mm width or less.