JP2012172014A - Composite resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite resin sheet having excellent transparency.SOLUTION: The composite resin sheet is formed from an epoxy resin including a cage type silsesquioxane having an alicyclic epoxy group, a vinyl polymer having an epoxy group or a hydroxy group, and a glass fiber.

Description

  The present invention relates to a composite resin sheet.

  Conventionally, for example, Patent Document 1 has been proposed as a glass fiber composite silsesquioxane molded body that can be used for a display element substrate or the like.

International Publication No. 2010/119903

However, the inventor of the present application has found that a glass fiber composite silsesquioxane molded body containing glass fiber and a cage-type silsesquioxane polymer cured product composited therewith has low transparency.
Then, an object of this invention is to provide the composite resin sheet excellent in transparency.

  As a result of earnest research to solve the above problems, the inventor of the present application is formed from an epoxy resin containing a cage-type silsesquioxane having an alicyclic epoxy group, a vinyl polymer having an epoxy group or a hydroxyl group, and glass fiber. The present inventors have found that the composite can be a composite resin sheet having excellent transparency, and completed the present invention.

That is, this invention provides the following 1-7.
1. A composite resin sheet formed from an epoxy resin containing a cage-type silsesquioxane having an alicyclic epoxy group, a vinyl polymer having an epoxy group or a hydroxyl group, and glass fiber.
2. 2. The composite resin sheet according to 1 above, wherein the amount of the silsesquioxane is 50% by mass or more based on the total amount of the epoxy resin.
3. The composite resin sheet according to 1 or 2, wherein the silsesquioxane is a compound represented by any one of the following formulas (B-1) to (B-3).



[In the formulas (B-1) to (B-3), at least two or all of the R's have an alicyclic epoxy group. ]
4). Furthermore, the composite resin sheet in any one of said 1-3 which contains the hardening | curing agent of the said epoxy resin, and the said hardening | curing agent is an acid anhydride.
5. The composite resin sheet according to any one of 1 to 4 above, wherein the vinyl polymer is a polyvinyl formal resin having a hydroxyl group and / or a polymethacrylate resin having an epoxy group.
6). The composite resin sheet according to any one of 1 to 5, wherein the amount of the vinyl polymer is 1 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin.
7). The composite resin sheet according to any one of 1 to 6 above, wherein the vinyl polymer has a weight average molecular weight of 1,000 to 100,000.

  The composite resin sheet of the present invention is excellent in transparency.

The present invention will be described in detail below.
The composite resin sheet of the present invention is a composite resin sheet formed from an epoxy resin containing a cage-type silsesquioxane having an alicyclic epoxy group, a vinyl polymer having an epoxy group or a hydroxyl group, and glass fiber.
A vinyl polymer having an epoxy group or a hydroxyl group can react with an epoxy resin containing a cage-type silsesquioxane having an alicyclic epoxy group.

The silsesquioxane will be described below. The composite resin sheet of the present invention contains an epoxy resin containing a cage-type silsesquioxane having an alicyclic epoxy group, and a vinyl polymer having an epoxy group or a hydroxyl group as a matrix resin, and a siloxane bond in the matrix resin. By providing the above, the refractive index of the matrix resin after curing can be made close to the refractive index of glass. The silsesquioxane used for the composite resin sheet of the present invention has an alicyclic epoxy group and is not particularly limited as long as the structure thereof is a cage type. The cage skeleton of silsesquioxane is a partial cage type in which a part of the siloxane bond (Si-O-Si) forming the skeleton is cleaved and the closed space is opened. Also good.
The alicyclic epoxy group is not particularly limited as long as it is a compound having one or more alicyclic groups and one or more oxirane groups. Examples of the alicyclic epoxy group include a cyclohexene oxide group, a norbornene oxide group, and a norbornane oxide group.
The alicyclic epoxy group can be bonded to the silicon atom of silsesquioxane through a divalent hydrocarbon group (for example, an alkylene group such as a methylene group or an ethylene group). Examples of such a group having an alicyclic epoxy group include a group having an alicyclic epoxy group such as (epoxycyclohexane) methyl group.
The number of alicyclic epoxy groups possessed by the silsesquioxane is preferably 8 to 12 functional groups, more preferably 8 to 10 functional groups, from the viewpoint of superior transparency, heat resistance, and toughness. preferable.

Silsesquioxane is preferably a compound represented by any one of the following formulas (B-1) to (B-3) from the viewpoint that it is more excellent in transparency, and is excellent in transparency and heat resistance. From the viewpoint of excellent toughness, a compound represented by the following formula (B-1) and / or the following formula (B-2) is more preferable.



[In the formulas (B-1) to (B-3), at least two or all of the R's have an alicyclic epoxy group. ]

When at least two of the plurality of Rs have an alicyclic epoxy group, other Rs are not particularly limited as long as they are hydrocarbon groups. The hydrocarbon group can have a functional group such as an epoxy group.
Silsesquioxanes can be used alone or in combination of two or more. Silsesquioxane is not particularly limited for its production. For example, a cage-type silsesquioxane having an alicyclic epoxy group is produced by condensing a trialkoxysilane having an alicyclic epoxy group using an alkali catalyst such as an aqueous solution of tetramethylammonium hydroxide. Can do.

The epoxy resin can include an epoxy resin other than a cage-type silsesquioxane having an alicyclic epoxy group. Epoxy resins other than cage-type silsesquioxane having an alicyclic epoxy group have an alicyclic epoxy group and a skeleton is a hydrocarbon group from the viewpoint of excellent transparency, heat resistance, and toughness. It is mentioned as a preferable aspect that it is an epoxy resin which is. The hydrocarbon group is not particularly limited. The hydrocarbon group can have, for example, a hetero atom such as an oxygen atom, a nitrogen atom, or a sulfur atom. Epoxy resins other than the cage-type silsesquioxane having an alicyclic epoxy group may not have a cage-type silsesquioxane. Examples of the epoxy resin other than the cage silsesquioxane having an alicyclic epoxy group include 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, 2- (3,4- Epoxy) cyclohexyl-5,5-spiro- (3,4-epoxy) cyclohexane-m-dioxane, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, vinylcyclohexane Dioxide, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, exo-exo bis (2,3-epoxycyclopentyl) ether, endo-exo bis ( 2,3-epoxycyclopentyl Ether, 2,2-bis (4- (2,3-epoxypropoxy) cyclohexyl) propane, 2,6-bis (2,3-epoxypropoxycyclohexyl-p-dioxane), 2,6-bis (2,3 -Epoxypropoxy) norbornene, diglycidyl ether of linoleic acid dimer, limonene dioxide, 2,2-bis (3,4-epoxycyclohexyl) propane, dicyclopentadiene dioxide, 1,2-epoxy-6- (2, 3-epoxypropoxy) hexahydro-4,7-methanoindane, p- (2,3-epoxy) cyclopentylphenyl-2,3-epoxypropyl ether, 1- (2,3-epoxypropoxy) phenyl-5,6-epoxy Hexahydro-4,7-methanoindane, o- (2,3-epoxy) cyclo Nchirufeniru 2,3-epoxypropyl ether), 1,2-bis [5- (1,2-epoxy) -4,7-hexa hydro meth Noin Dano cyclohexyl] ethane.
Epoxy resins other than cage-type silsesquioxane having an alicyclic epoxy group can be used alone or in combination of two or more.

  The amount of silsesquioxane is 50% by mass or more based on the total amount of the epoxy resin from the viewpoint that the transparency of the glass fiber and the matrix resin are combined to make the transparency more excellent and the heat resistance and toughness are excellent. It is preferable that it is 60 to 90% by mass.

  The vinyl polymer will be described below. By containing a vinyl polymer, the composite resin sheet of the present invention can improve transparency without impairing heat resistance. The vinyl polymer used in the composite resin sheet of the present invention is not particularly limited as long as it is a compound having an epoxy group or a hydroxyl group (hydroxy group) and a skeleton formed by polymerization of a monomer having at least a vinyl group. Examples of the main chain include polyvinyl alcohol resin, polyvinyl acetate resin, polyethylene-vinyl acetate resin, polyvinyl formal resin, and poly (meth) acrylate resin. In the present invention, (meth) acrylate means one or both of acrylate and methacrylate. The same applies to (meth) acrylic.

  The epoxy group and hydroxyl group of the vinyl polymer can be bonded to the main chain via a single bond or an organic group. The organic group is not particularly limited. For example, an aliphatic hydrocarbon group (which may be linear, branched, cyclic, or a combination thereof, and may have an unsaturated bond), an aromatic hydrocarbon group, or a combination thereof may be mentioned. The organic group can have a hetero atom such as an oxygen atom, a nitrogen atom, or a sulfur atom. Examples of the organic group include an ester bond, an alkylene group, an ether bond, and a combination thereof.

  The vinyl polymer is preferably a polyvinyl formal resin having a hydroxyl group and / or a poly (meth) acrylate resin having an epoxy group, from the viewpoint of excellent transparency, heat resistance, and toughness, and a polyvinyl formal having a hydroxyl group. A polymethacrylate resin having a resin and / or an epoxy group is more preferable.

The weight average molecular weight of the vinyl polymer is preferably 1,000 to 100,000 from the viewpoints of excellent transparency, heat resistance, and toughness. The weight average molecular weight of the vinyl polymer was determined in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.
The vinyl polymers can be used alone or in combination of two or more. The vinyl polymer is not particularly limited for its production. For example, a conventionally well-known thing is mentioned.

  The amount of the vinyl polymer is preferably 1 to 30 parts by mass, preferably 3 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin, from the viewpoint of being excellent in transparency, heat resistance and toughness. More preferred.

The glass fiber will be described below. The composite resin sheet of the present invention uses glass fibers as a reinforcing material. The glass fiber used for the composite resin sheet of the present invention is not particularly limited. For example, glass fiber woven fabrics such as glass cloth; glass nonwoven fabrics can be mentioned. Among these, a glass fiber woven fabric is preferable, and a glass cloth is more preferable from the viewpoint of excellent transparency, heat resistance, and toughness.
Examples of the glass fiber glass material include E glass, C glass, A glass, S glass, T glass, D glass, NE glass, quartz, low dielectric constant glass, and high dielectric constant glass. Among these, E glass and NE glass are preferable from the viewpoints of excellent transparency, excellent heat resistance and toughness, and few impurities.
The refractive index of the glass fiber is preferably 1.55 to 1.57, more preferably 1.555 to 1.565. The glass fibers can be used alone or in combination of two or more.

  The amount of the glass fiber is preferably 30 to 70% by mass, more preferably 45 to 65% by mass in the transparent composite sheet, from the viewpoint that it is excellent in transparency and excellent in heat resistance and toughness.

  The composite resin sheet of the present invention may further contain a curing agent for the epoxy resin. The curing agent for epoxy resin that can be further used in the composite resin sheet of the present invention is not particularly limited as long as it is a curing agent that can be used for epoxy resin. For example, an acid anhydride, a polyamine, a polyphenol, a polymercaptan, a cationic polymerization system, and an anionic polymerization system are mentioned. Of these, acid anhydrides are preferred from the viewpoints of better transparency, heat resistance, and toughness.

Examples of the acid anhydride include aromatic acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyromellitic anhydride; alicyclic acid anhydrides. The alicyclic hydrocarbon that the alicyclic acid anhydride has can have an unsaturated bond. Examples of alicyclic acid anhydrides include unsaturated alicyclic carboxylic acid anhydrides such as maleic anhydride, tetrahydrophthalic anhydride, nadic anhydride, and methyl nadic anhydride; hexahydrophthalic anhydride, 3-methyl- Cyclohexanedicarboxylic acid anhydride, 4-methyl-cyclohexanedicarboxylic acid anhydride, mixture of 3-methyl-cyclohexanedicarboxylic acid anhydride and 4-methyl-cyclohexanedicarboxylic acid anhydride, norbornane-2,3-dicarboxylic acid anhydride, methyl And saturated alicyclic carboxylic acid anhydrides such as norbornane-2,3-dicarboxylic acid anhydride. Among these, from the viewpoint of excellent color resistance and low viscosity, alicyclic acid anhydrides are preferable, saturated alicyclic carboxylic acid anhydrides are more preferable, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride. More preferred are acids and combinations thereof.
The curing agents can be used alone or in combination of two or more.

  The amount of the curing agent is preferably 0.8 to 1.2 equivalents relative to the epoxy group in the epoxy resin from the viewpoint of excellent transparency, heat resistance and toughness, and 0.9 to 1 More preferably, it is 0.0 equivalent.

  The composite resin sheet of the present invention may further contain an additive as long as it does not impair the properties such as transparency, heat resistance, toughness, solvent resistance, low heat resistance, optical properties, and flatness. it can. Examples of additives include thermoplastic resins other than vinyl polymers, thermosetting resins other than epoxy resins such as oxetane, silane coupling agents, antioxidants, ultraviolet absorbers, dyes and pigments, inorganic fillers other than glass fibers, A flame retardant, a catalyst (for example, amine), and a solvent are mentioned.

If the composite resin sheet of the present invention is formed using an epoxy resin containing a cage silsesquioxane having an alicyclic epoxy group, a vinyl polymer having an epoxy group or a hydroxyl group, and glass fiber, The manufacturing method is not particularly limited. For example, a resin composition for a composite resin sheet containing components other than glass fibers (containing at least an epoxy resin containing silsesquioxane and a vinyl polymer) is prepared in advance, and (1) the obtained composite resin sheet is used. A method in which a resin composition and glass fiber are directly mixed and cast into a necessary one and then cross-linked into a sheet, (2) an uncured resin composition for a composite resin sheet or a resin composition for a composite resin sheet Examples thereof include a method in which a glass fiber is impregnated with a varnish dissolved in a solvent and then crosslinked to form a sheet.
As preparation of the resin composition for composite resin sheets, the method of heating and mixing components other than glass fiber to room temperature to 60 degreeC is mentioned, for example.
The crosslinking temperature at the time of producing the composite resin sheet of the present invention can be 80 to 200 ° C. In addition, the cross-linking is not performed completely, and the composite resin sheet of the present invention is made into a semi-cross-linked state (B stage), and then heated, for example, while degassing under reduced pressure or sandwiching and pressing with a press machine It can be cured.

  In the transparent composite sheet of the present invention, the difference between the refractive index after curing of the resin composition for a composite resin sheet and the refractive index of the glass fiber is preferably 0.01 or less in order to maintain excellent transparency. More preferably, it is 0.005 or less.

  Applications of the transparent composite sheet of the present invention include, for example, LED sealing materials, display substrates (substrates for liquid crystal display elements, substrates for organic EL display elements, substrates for color filters, substrates for electronic paper), solar cell substrates. And optical applications such as a touch panel. Moreover, the composite resin sheet of this invention can be used as a glass substitute material and a transparent sealing material.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
<Preparation of resin composition for composite resin sheet>
The components shown in Table 1 below were used in the amounts (parts by mass) used in the same table, and these were mixed to prepare a resin composition for a composite resin sheet. Let the obtained resin composition for composite resin sheets be resin 1-8.
<Manufacture of composite resin sheet>
100 g of the resin composition for a composite resin sheet obtained as described above was heated to 60 ° C., and a glass cloth (manufactured by Nittobo Co., Ltd., trade name: 1080 (thickness: 55 μm), length: 10 cm, width: 10 cm, An uncured composite resin sheet was manufactured by dipping in a glass cloth for a weight of 0.47 g and material glass (E glass, plain weave). The obtained uncured composite resin sheet was heated and cured at 100 ° C. for 30 minutes, 150 ° C. for 2 hours, and 200 ° C. for 30 minutes while degassing under reduced pressure to produce a composite resin sheet having a thickness of 80 μm. The composite resin sheet after heat curing is completely cured. The obtained composite resin sheet weighed 1.17 g.

<Evaluation>
Using the composite resin sheet obtained as described above, the glass transition temperature (Tg) of the composite resin sheet and the transparency of the composite resin sheet were evaluated by the following methods. The results are shown in Table 1.
1. Glass transition temperature (Tg) For each cured product (composite resin sheet), a dynamic viscoelasticity measurement (Dynamic Mechanical Analysis) was performed from room temperature to 200% at a strain of 0.01%, a frequency of 10 Hz, and a heating rate of 5 ° C / min. In the temperature range up to 0 ° C., forced elongation was applied to measure the storage elastic modulus. The peak value of tan δ was defined as the glass transition temperature Tg of each composite resin sheet.
2. Transparency About each hardened | cured material (composite resin sheet | seat), according to JISK0115: 2004, the transmittance | permeability in wavelength 400nm was measured using the ultraviolet-visible (UV-Vis) absorption-spectrum measuring apparatus (made by Shimadzu Corp.).

The details of each component shown in Table 1 are as follows.
Epoxy resin (1): 200 g of KBM303 [2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane] manufactured by Shin-Etsu Chemical Co., Ltd. was dissolved in 500 g of methyl ethyl ketone by a known method for producing silsesquioxane. A 45% aqueous solution of tetramethylammonium hydroxide was used as a catalyst (as an alkali catalyst), and the mixture was hydrolytically condensed at room temperature. After the reaction, it was confirmed by ¹ H-NMR analysis that the methoxy group of KBM303 had completely disappeared. Moreover, it confirmed that it was monodispersed by GPC analysis. It is considered that the result of GPC analysis being monodispersed indicates that the obtained epoxy resin is not a ladder type. Let the obtained epoxy resin be an epoxy resin (1). The epoxy resin (1) is a cage silsesquioxane having an alicyclic epoxy group, and is a mixture of a compound represented by the above formula (B-1) and a compound represented by the above formula (B-2). It is thought that.
Epoxy resin (2): Daicel Chemical Industries, Celoxide 2021P, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate Acid anhydride 1: Shin Nippon Rika, MH700, 4- Methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30
-Polyvinyl formal resin 1: Vinylec C manufactured by Chisso Corporation, weight average molecular weight 66,000 (weight average molecular weight determined by polystyrene conversion by gel permeation chromatography (GPC) using tetrahydrofuran as solvent), converted by polyvinyl alcohol 5 wt%
・ Poly (methyl methacrylate-glycidyl methacrylate) 1: Methyl methacrylate and glycidyl methacrylate are radically polymerized in methyl ethyl ketone (MEK) at a weight ratio of 1: 2, and a powdery resin (copolymer of methyl methacrylate and glycidyl methacrylate) is obtained. Obtained. The obtained resin is designated as poly (methyl methacrylate-glycidyl methacrylate) 1. The weight average molecular weight of poly (methyl methacrylate-glycidyl methacrylate) 1 was 67,000 (weight average molecular weight determined by polystyrene conversion by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent).
Polymer having no OH group and epoxy group: Methyl methacrylate was polymerized at 33 ° C. for 20 hours at 65 ° C. using a 33 wt% solution of methyl ethyl ketone as an initiator. The weight average molecular weight was 60,000 (weight average molecular weight determined in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent).
・ Catalyst 1: Amine-based catalyst manufactured by San Apro, U-CAT 18X

As is clear from the results shown in Table 1, Comparative Example 1 containing no vinyl polymer, Comparative Example 2 containing no silsesquioxane, and Comparative Example 3 containing a polymer other than a vinyl polymer having an epoxy group or a hydroxyl group are transparent. The sex was low.
On the other hand, Examples 1-5 are excellent in transparency. In Examples 1 to 5, transparency was improved by adding a vinyl polymer to the system without impairing heat resistance.
Thus, the composite resin sheet of this invention is excellent in heat resistance, transparency, and toughness.

Claims (7)

  A composite resin sheet formed from an epoxy resin containing a cage-type silsesquioxane having an alicyclic epoxy group, a vinyl polymer having an epoxy group or a hydroxyl group, and glass fiber.   The composite resin sheet according to claim 1, wherein the amount of the silsesquioxane is 50% by mass or more based on the total amount of the epoxy resin. The composite resin sheet according to claim 1 or 2, wherein the silsesquioxane is a compound represented by any one of the following formulas (B-1) to (B-3).



[In the formulas (B-1) to (B-3), at least two or all of the R's have an alicyclic epoxy group. ]   The composite resin sheet according to claim 1, further comprising a curing agent for the epoxy resin, wherein the curing agent is an acid anhydride.   The composite resin sheet according to any one of claims 1 to 4, wherein the vinyl polymer is a polyvinyl formal resin having a hydroxyl group and / or a polymethacrylate resin having an epoxy group.   The composite resin sheet according to any one of claims 1 to 5, wherein an amount of the vinyl polymer is 1 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin.   The composite resin sheet according to any one of claims 1 to 6, wherein the vinyl polymer has a weight average molecular weight of 1,000 to 100,000.