JP2007238778A - Transparent composite sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent composite sheet with a small coefficient of linear expansion, excellent transparency and heat resistance and further excellent flexibility. <P>SOLUTION: In the transparent composite sheet obtained by curing a composite composition containing an epoxy resin composition containing an alicyclic epoxy resin, a curing agent and a coupling agent and a glass filler, the alicyclic epoxy resin contains the alicyclic epoxy resin represented by chemical formula (1) or chemical formula (2). In the chemical formula (1) and the chemical formula (2), -X- represents -O-, -S-, -SO-, -SO<SB>2</SB>-, -CH<SB>2</SB>-, -CH(CH<SB>3</SB>)- or -C(CH<SB>3</SB>)<SB>2</SB>-. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transparent composite sheet having a small linear expansion coefficient and excellent flexibility.

  In general, glass plates are widely used as display element substrates (particularly active matrix type) for liquid crystal display elements and organic EL display elements, color filter substrates, solar cell substrates, and the like. However, in recent years, plastic materials have been studied as an alternative to glass plates because they are easily broken, cannot be bent, have a large specific gravity, and are not suitable for weight reduction.

For example, Patent Document 1 describes a transparent resin substrate for a liquid crystal display element obtained by curing an epoxy resin composition containing an alicyclic epoxy resin, a curing catalyst, and a glass filler. The plastic material has the flexibility that cannot be obtained with a glass substrate, so a long substrate is used while being wound on a roll, and the function of the liquid crystal panel is achieved by sequentially feeding from the unwinding side to the winding side. It is possible to form various functional thin films.
However, these conventional transparent resin substrates have a problem that cracks are likely to occur in the resin in various processes in which various functional thin films are formed, particularly when a load such as bending occurs. For this reason, there is a demand for a material that has a low coefficient of linear expansion while satisfying transparency, heat resistance, and the like, and is more flexible.

JP 2004-51960 A

  An object of the present invention is to provide a transparent composite sheet having a small coefficient of linear expansion, excellent transparency and heat resistance, and excellent flexibility.

（式中、Ｘは−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ₂−、−ＣＨ₂−、−ＣＨ(ＣＨ₃)−、又は−Ｃ(ＣＨ₃)₂−を表す。）
（２）前記脂環式エポキシ樹脂と前記カップリング剤との配合の重量比が、９９．９９：０．０１〜９５：５である（１）１記載の透明複合シート、
（３）前記カップリング剤が、エポキシ基、アミノ基、ヒドロキシル基、メルカプト基、ビニル基、（メタ）アクリロイル基から選ばれた少なくとも一種の官能基と、アルコキシ基とを有するものである（１）又は（２）記載の透明複合シート、
（４）前記硬化剤が、カチオン系硬化触媒を含むものである（１）〜（３）いずれか記載の透明複合シート、
（５）前記ガラスフィラーの含有量が、透明複合シートに対し１〜９０重量％である（１）〜（４）いずれか記載の透明複合シート、
（６）前記ガラスフィラーが、ガラス繊維布である（１）〜（５）いずれか記載の透明複合シート、
（７）前記ガラスフィラーの３０℃から２５０℃における平均線膨張率が５ｐｐｍ以下である（１）〜（６）いずれか記載の透明複合シート、
（８）前記ガラスフィラーが、Ｔガラスである（１）〜（７）いずれか記載の透明複合シート、
（９）厚みが、４０〜２００μｍである（１）〜（８）いずれか記載の透明複合シート、
（１０）波長４００ｎｍにおける光線透過率が８０％以上である（１）〜（９）いずれか記載の透明複合シート、
（１１）３０〜２５０℃における平均線膨張率が１０ｐｐｍ以下である請求項１〜１０いずれか記載の透明複合シート、
（１２）（１）〜（１１）いずれか記載の透明複合シートから構成される表示素子用基板、
である。 The present invention
(1) A transparent composite sheet obtained by curing a composite composition comprising an epoxy resin composition containing an alicyclic epoxy resin, a curing agent, and a coupling agent and a glass filler, the alicyclic A transparent composite sheet, wherein the epoxy resin contains an alicyclic epoxy resin represented by the following chemical formula (1) or (2):

(In the formula, X represents —O—, —S—, —SO—, —SO ₂ —, —CH ₂ —, —CH (CH ₃ ) —, or —C (CH ₃ ) ₂ —).
(2) The transparent composite sheet according to (1), wherein a weight ratio of the alicyclic epoxy resin and the coupling agent is 99.99: 0.01 to 95: 5,
(3) The coupling agent has at least one functional group selected from an epoxy group, an amino group, a hydroxyl group, a mercapto group, a vinyl group, and a (meth) acryloyl group, and an alkoxy group (1 ) Or (2) the transparent composite sheet,
(4) The transparent composite sheet according to any one of (1) to (3), wherein the curing agent contains a cationic curing catalyst,
(5) The transparent composite sheet according to any one of (1) to (4), wherein the content of the glass filler is 1 to 90% by weight based on the transparent composite sheet,
(6) The transparent composite sheet according to any one of (1) to (5), wherein the glass filler is a glass fiber cloth,
(7) The transparent composite sheet according to any one of (1) to (6), wherein an average linear expansion coefficient at 30 ° C. to 250 ° C. of the glass filler is 5 ppm or less,
(8) The transparent composite sheet according to any one of (1) to (7), wherein the glass filler is T glass,
(9) The transparent composite sheet according to any one of (1) to (8), wherein the thickness is 40 to 200 μm,
(10) The transparent composite sheet according to any one of (1) to (9), wherein the light transmittance at a wavelength of 400 nm is 80% or more,
(11) The average linear expansion coefficient in 30-250 degreeC is 10 ppm or less, The transparent composite sheet in any one of Claims 1-10,
(12) A substrate for a display element comprising the transparent composite sheet according to any one of (1) to (11),
It is.

  Since the transparent composite sheet of the present invention is excellent in transparency, heat resistance and flexibility and has a small linear expansion coefficient, it is a liquid crystal display element substrate including an active matrix type, an organic EL display element substrate, a color filter substrate, and a touch panel. It is suitably used for optical sheets such as substrates, substrates for electronic paper, and solar cell substrates.

Hereinafter, the present invention will be described in detail.
The transparent composite sheet of the present invention is a transparent composite sheet obtained by curing a composite composition comprising an epoxy resin composition containing an alicyclic epoxy resin, a curing agent, and a coupling agent, and a glass filler. .
The alicyclic epoxy resin used in the present invention includes a hydrogenated biphenyl type epoxy resin represented by the following chemical formula (1) or an alicyclic epoxy resin represented by the following chemical formula (2).

（式中、Ｘは−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ₂−、−ＣＨ₂−、−ＣＨ(ＣＨ₃)−、又は−Ｃ(ＣＨ₃)₂−を表す。）

(In the formula, X represents —O—, —S—, —SO—, —SO ₂ —, —CH ₂ —, —CH (CH ₃ ) —, or —C (CH ₃ ) ₂ —).

  The curing agent for the alicyclic epoxy resin used in the present invention is not particularly limited, and an acid anhydride, an aliphatic amine, a cationic curing catalyst, an anionic curing catalyst, or the like can be used.

  However, it is preferable to use a cationic curing catalyst from the viewpoint of heat resistance and the like. Examples of the cationic curing catalyst include an initiator that releases a substance that initiates cationic polymerization by heating and an initiator that releases a substance that initiates cationic polymerization by active energy rays. A cured product having high heat resistance can be obtained. Therefore, an initiator that releases a substance that initiates cationic polymerization by heating, that is, a thermal cationic curing catalyst is particularly preferable.

  Preferred thermal cation curing catalysts include aromatic sulfonium salts, aromatic iodonium salts, aluminum chelates and the like. Specific examples include aromatic sulfonium salts such as SI-60L, SI-80L, SI-100L manufactured by Sanshin Chemical Industry, CP-66, CP-77 manufactured by Asahi Denka Kogyo Co., Ltd. Is Daicel Chemical Industries' DAICAT EX-1.

  The coupling agent used in the present invention has at least one functional group selected from an epoxy group, an amino group, a hydroxyl group, a mercapto group, a vinyl group, and a (meth) acryloyl group, and an alkoxy group. preferable.

Examples of these coupling agents include silane coupling agents, titanate coupling agents, aluminum coupling agents, aluminum / zirconium coupling agents, and silane coupling agents are preferred.
Examples of the silane coupling agent include epoxy silane, mercapto silane, amino silane, ureido silane, vinyl silane, and the like. Ethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Examples thereof include propylmethyldimethoxysilane, β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, vinyltriethoxysilane and the like. Of these, epoxysilane is preferred.

  The blending amount of the coupling agent is not particularly limited, but the weight ratio of the blending of the alicyclic epoxy resin and the coupling agent is preferably 99.99: 0.01 to 95: 5, and 99.95. : 0.05 to 98: 2 is more preferable, and 99.9: 0.1 to 99: 1 is particularly preferable. If the blending amount of the coupling agent is less than the lower limit value, the flexibility of the transparent composite sheet is not improved, and if it exceeds the upper limit value, heat resistance and toughness may be lowered.

  Examples of the glass filler used in the present invention include glass fiber cloth such as glass fiber, glass cloth and glass nonwoven fabric, glass beads, glass flakes, glass powder, and milled glass. Among them, the effect of reducing the linear expansion coefficient is high. Glass fiber, glass cloth and glass nonwoven fabric are preferable, and glass cloth is most preferable.

  Examples of the glass include E glass, C glass, A glass, S glass, D glass, NE glass, T glass, quartz, low dielectric constant glass, and high dielectric constant glass. E glass, S glass, T glass, and NE glass, which have few impurities and are easily available, are preferable, and S glass or T glass having a low thermal expansion coefficient is particularly preferable. For these, for example, glass fiber (trade name “T glass”) sold by Nitto Boseki Co., Ltd. can be suitably used.

  The glass filler used in the present invention preferably has an average linear expansion coefficient at 30 to 250 ° C. of 5 ppm or less.

  It is preferable that content of a glass filler is 1 to 90 weight% with respect to a transparent composite sheet, More preferably, it is 10 to 80 weight%, More preferably, it is 30 to 70 weight%. If the content of the glass filler is within this range, molding is easy, and the effect of reducing linear expansion due to compounding is recognized.

  In the transparent composite sheet of the present invention, if necessary, thermoplastic or thermosetting oligomers or polymers may be used in combination as long as the properties such as transparency, solvent resistance, and heat resistance are not impaired. When these thermoplastic or thermosetting oligomers and polymers are used in combination, the composition ratio is preferably adjusted so that the overall refractive index matches the refractive index of the glass filler. In the transparent composite sheet of the present invention, if necessary, a small amount of antioxidant, ultraviolet absorber, dye / pigment, and the like, as long as the properties such as transparency, solvent resistance and heat resistance are not impaired. It may contain a filler such as an inorganic filler.

  There is no limitation on the molding method of the transparent composite sheet of the present invention, for example, a method in which an uncured epoxy resin composition and a glass filler are directly mixed, cast into a required mold and then cross-linked into a sheet, uncured A method in which the epoxy resin composition is dissolved in a solvent and the glass filler is dispersed and cast, and then cross-linked to form a sheet or the like. And the like.

  When the transparent composite sheet of the present invention is used for optical applications such as a liquid crystal display element plastic substrate, a color filter substrate, an organic EL display element plastic substrate, an electronic paper substrate, a solar cell substrate, a touch panel, etc. A substrate shape is preferred. The thickness of the sheet is preferably 30 to 1000 μm, more preferably 40 to 200 μm. When the thickness of the sheet is in this range, the flatness is excellent, and the weight of the substrate can be reduced as compared with the glass substrate.

  When the transparent composite sheet of the present invention is used as the optical application, the average linear expansion coefficient at 30 ° C. to 250 ° C. is preferably 30 ppm or less, more preferably 20 ppm or less, and most preferably 10 ppm or less. For example, when this transparent composite sheet is used for an active matrix display element substrate, if this upper limit is exceeded, problems such as warping and disconnection of aluminum wiring may occur in the manufacturing process.

  When using the transparent composite sheet of this invention as a plastic substrate for display elements, it is preferable that the light transmittance in wavelength 400nm is 80% or more, More preferably, it is 85% or more. If the light transmittance at a wavelength of 400 nm is less than the lower limit, the display performance may not be sufficient.

  When the transparent composite sheet of the present invention is used as a plastic substrate for a display element, a resin coat layer may be provided on both sides of the substrate in order to improve surface smoothness. The resin to be used preferably has excellent heat resistance, transparency, and chemical resistance, and specifically, a polyfunctional acrylate resin or an epoxy resin is preferable. The thickness of the coat layer is preferably 0.1 μm to 30 μm, more preferably 0.5 to 30 μm.

  EXAMPLES Hereinafter, although the content of this invention is demonstrated in detail by an Example, this invention is not limited to the following examples, unless the summary is exceeded.

Example 1
Hydrogenated biphenyl type alicyclic epoxy resin (E-BP, manufactured by Daicel Chemical Industries) having a structure of chemical formula (1) on T glass-based glass cloth (thickness 95 μm, refractive index 1.520, manufactured by Nittobo, WTX116F) 99 parts by weight, 1 part by weight of β- (3,4 epoxy cyclohexyl) ethyltrimethoxysilane (KBM303, manufactured by Shin-Etsu Chemical Co., Ltd.), 1 part by weight of an aromatic sulfonium-based thermal cation catalyst (SI-100L, manufactured by Sanshin Chemical) The mixed epoxy resin composition was impregnated and defoamed. The glass cloth was sandwiched between release-molded glass plates, heated at 80 ° C. for 2 hours, and further heated at 250 ° C. for 2 hours to obtain a transparent composite sheet having a thickness of 97 μm (glass filler content: 63 wt%).

(Example 2)
Hydrogenated biphenyl type alicyclic epoxy resin (E-BP, manufactured by Daicel Chemical Industries) having a structure of chemical formula (1) on T glass-based glass cloth (thickness 95 μm, refractive index 1.520, manufactured by Nittobo, WTX116F) 99.9 parts by weight, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (KBM303, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 parts by weight, aromatic sulfonium-based thermal cation catalyst (SI-100L, manufactured by Sanshin Chemical) An epoxy resin composition mixed with 1 part by weight was impregnated and defoamed. This glass cloth was sandwiched between release-treated glass plates, heated at 80 ° C. for 2 hours, and further heated at 250 ° C. for 2 hours to obtain a transparent composite sheet having a thickness of 96 μm (glass filler content: 63 wt%).

(Example 3)
Hydrogenated biphenyl type alicyclic epoxy resin (E-BP, manufactured by Daicel Chemical Industries) having a structure represented by chemical formula (1) in NE glass-based glass cloth (thickness 90 μm, refractive index 1.510, manufactured by Nittobo, NEA2319) 99.8 parts by weight, γ-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.2 parts by weight, aromatic sulfonium-based thermal cation catalyst (SI-100L, manufactured by Sanshin Chemical Co., Ltd.) 1 part by weight The resulting epoxy resin composition was impregnated and defoamed. This glass cloth was sandwiched between release-treated glass plates, heated at 80 ° C. for 2 hours, and further heated at 250 ° C. for 2 hours to obtain a transparent composite sheet having a thickness of 93 μm (glass filler content: 62% by weight).

(Comparative Example 1)
Hydrogenated biphenyl type alicyclic epoxy resin (E-BP, manufactured by Daicel Chemical Industries) having the structure of chemical formula (1) in E glass-based glass cloth (thickness 94 μm, refractive index 1.560, manufactured by Nitto Boseki Co., Ltd., WEA2116) A resin composition mixed with 100 parts by weight and 1 part by weight of an aromatic sulfonium-based thermal cation catalyst (SI-100L, manufactured by Sanshin Chemical Co., Ltd.) was impregnated and defoamed. This glass cloth was sandwiched between release-treated glass plates, heated at 80 ° C. for 2 hours, and further heated at 250 ° C. for 2 hours to obtain a transparent composite sheet having a thickness of 96 μm (glass filler content: 62% by weight).

About the transparent composite sheet produced as mentioned above, various characteristics were measured with the evaluation method shown below.
a) Average linear expansion coefficient Using a TMA / SS6000 type thermal stress strain measuring device manufactured by Seiko Instruments Inc., measurement is performed in a tensile mode (load: 5 g) at 5 ° C. for 1 minute in the presence of nitrogen. The average linear expansion coefficient in the temperature range was calculated.
b) Light transmittance The light transmittance at 400 nm was measured with a spectrophotometer U3200 (manufactured by Hitachi, Ltd.).
c) Bending resistance As shown in FIG. 1, the transparent composite sheet 1 cut to a width of 10 mm is wound around a round bar 2, and a 500 g weight 3 is hung to suspend the diameter of the round bar where cracks enter the transparent composite sheet. The diameter.

  Table 1 shows the composition of the transparent composite sheets of Examples and Comparative Examples and the evaluation results of the properties.

Schematic showing the test method for bending resistance of transparent composite sheet

Explanation of symbols

1 Transparent composite sheet 2 Round bar 3 Weight

Claims (12)

A transparent composite sheet obtained by curing a composite composition comprising an epoxy resin composition containing an alicyclic epoxy resin, a curing agent, and a coupling agent, and a glass filler, the alicyclic epoxy resin Which contains an alicyclic epoxy resin represented by the following chemical formula (1) or (2).

(Wherein, -X- is -O -, - S -, - SO -, - SO 2 -, - CH 2 -, - CH (CH 3) -, or -C (CH _{3) 2} - represents a. ) The transparent composite sheet according to claim 1, wherein a weight ratio of the alicyclic epoxy resin and the coupling agent is 99.99: 0.01 to 95: 5. The coupling agent has at least one functional group selected from an epoxy group, an amino group, a hydroxyl group, a mercapto group, a vinyl group, and a (meth) acryloyl group, and an alkoxy group. The transparent composite sheet as described. The transparent composite sheet according to claim 1, wherein the curing agent contains a cationic curing catalyst. The transparent composite sheet according to any one of claims 1 to 4, wherein a content of the glass filler is 1 to 90% by weight with respect to the transparent composite sheet. The transparent composite sheet according to claim 1, wherein the glass filler is a glass fiber cloth. The transparent composite sheet according to any one of claims 1 to 6, wherein an average linear expansion coefficient of the glass filler at 30 ° C to 250 ° C is 5 ppm or less. The transparent composite sheet according to any one of claims 1 to 7, wherein the glass filler is T glass. Thickness is 40-200 micrometers, The transparent composite sheet in any one of Claims 1-8. The transparent composite sheet according to any one of claims 1 to 9, wherein the light transmittance at a wavelength of 400 nm is 80% or more. The transparent composite sheet according to any one of claims 1 to 10, wherein an average linear expansion coefficient at 30 to 250 ° C is 10 ppm or less. The substrate for display elements comprised from the transparent composite sheet in any one of Claims 1-11.

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