JP2011068761A - Transparent composite sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent composite sheet which can secure a high glass transition temperature while maintaining high transparency, can inhibit discoloration by heat, and furthermore does not require a solvent drying step. <P>SOLUTION: The transparent composite sheet 1 includes a transparent resin 5 held by a base material 4 of glass fibers and the transparent resin 5 is a cured product of a resin composition containing diallyl monoglycidyl isocyanurate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a transparent composite sheet.

  Conventionally, in a flat panel display such as a liquid crystal display, a plasma display, and an EL display, a transparent composite sheet in which a transparent resin is held on a glass fiber substrate has been proposed as an alternative to a glass plate (for example, a patent) Reference 1).

  When manufacturing such a transparent composite sheet, for example, a high refractive index resin having a higher refractive index than that of glass fiber and a low refractive index resin having a lower refractive index than that of glass fiber are mixed to make the refractive index of glass. A resin composition is prepared so as to approximate the refractive index of the fiber. Then, a glass fiber substrate is impregnated with the resin composition, dried and semi-cured to prepare a prepreg, and the prepreg is heated and pressed to produce a transparent composite sheet. In addition, since the prepared resin composition is generally high in viscosity or solid, the glass fiber base material cannot be impregnated. For this reason, a solvent such as toluene or methyl ethyl ketone is added for dilution.

  Thus, by combining the refractive indexes of the glass fiber as the base material and the transparent resin, the refraction of light in the transparent composite sheet can be suppressed and used as a transparent film of a display having excellent visibility.

  Epoxy resin is generally used as a resin composition for producing a transparent composite sheet, and an epoxy resin having a refractive index larger than that of glass fiber and glass in order to approximate its refractive index to that of glass fiber. A resin composition is prepared by mixing an epoxy resin having a refractive index smaller than that of the fiber so that the refractive index approximates that of the glass fiber, and further adding a solvent such as toluene or methyl ethyl ketone. The varnish is being prepared.

JP 2004-307851 A

  However, in a transparent composite sheet using an epoxy resin as a resin composition, a high refractive index epoxy resin having a relatively high glass transition temperature is used in order to obtain heat resistance. When a relatively high material is used, the transparent composite sheet may turn yellow due to heat. Moreover, when the solvent is contained in the varnish of the resin composition, not only does the production process adversely affect the global environment due to its discharge, but also there is a problem that foreign matters are easily mixed into the product in the drying process.

  The present invention has been made in view of the circumstances as described above, can maintain a high glass transition temperature while maintaining high transparency, can suppress discoloration due to heat, and further does not require a solvent drying step. The problem is to provide a composite sheet.

  The present invention is characterized by the following.

  1stly, in the transparent composite sheet by which the transparent resin is hold | maintained at the base material of glass fiber, the said transparent resin is a hardened | cured material of the resin composition containing diallyl monoglycidyl isocyanuric acid, It is characterized by the above-mentioned.

  Second, in the first invention, the resin composition is characterized by containing a bisphenol-type epoxy resin or an epoxy resin having a 3,4-epoxycyclohexenyl skeleton.

  Third, in the second invention, the bisphenol type epoxy resin is at least one selected from a liquid bisphenol A type epoxy resin, a liquid bisphenol F type epoxy resin, and a trifunctional epoxy resin having a bisphenol A skeleton. It is characterized by.

  4thly, in the said 1st invention, the resin composition contains cyanate ester resin, It is characterized by the above-mentioned.

  Fifth, in any one of the first to fourth inventions, the glass transition temperature of the transparent resin is 200 ° C. or higher.

  Sixth, in any one of the first to fifth inventions, a difference in refractive index between the glass fiber and the transparent resin is 0.02 or less.

  According to the first to third inventions, by using a resin composition containing diallyl monoglycidyl isocyanuric acid, a high glass transition temperature can be ensured while maintaining high transparency, and discoloration due to heat can be suppressed. . Furthermore, since the viscosity of the varnish of the resin composition is low, a solvent such as toluene or methyl ethyl ketone becomes unnecessary.

  According to the said 4th invention, the glass transition temperature of the hardened | cured material of a resin composition can further be raised by using cyanate ester resin.

  According to the fifth aspect, in addition to the effects of the first to fourth aspects, a transparent composite sheet having excellent heat resistance can be obtained due to the high glass transition temperature of the transparent resin.

  According to the sixth invention, since the difference in refractive index between the glass fiber and the transparent resin is 0.02 or less, in addition to the effects of the first to fifth inventions, the transparency of the transparent composite sheet is further improved. Can be increased.

It is sectional drawing which shows one Embodiment of the transparent composite sheet concerning this invention.

Hereinafter, the present invention will be described in detail.

  FIG. 1 is a cross-sectional view showing an embodiment of a transparent composite sheet according to the present invention. The transparent composite sheet 1 is configured by holding a transparent resin 5 on a glass fiber base material 4 such as a woven fabric or a nonwoven fabric composed of a plurality of warp fiber bundles 2 and a plurality of weft fiber bundles 3.

  The transparent resin is a cured product of an epoxy resin composition containing diallyl monoglycidyl isocyanuric acid represented by the following formula (1).

  By using a resin composition containing diallyl monoglycidyl isocyanuric acid, a high glass transition temperature can be secured while maintaining high transparency, discoloration due to heat can be suppressed, and a solvent is unnecessary. Thus, in order to obtain the desired effect by containing diallyl monoglycidyl isocyanuric acid, the amount of diallyl monoglycidyl isocyanuric acid is preferably 50 to 80% by mass in the total resin components of the resin composition. However, the ratio is preferably 55 to 75% by mass.

  Since the refractive index of diallyl monoglycidyl isocyanuric acid is relatively close to the refractive index of glass fiber, high transparency can be maintained as described above. In order to ensure the transparency of the transparent composite sheet more reliably, it is desirable to use a resin composition prepared so that the refractive index of the resin composition approximates the refractive index of the glass fiber, and appropriate refraction along with diallyl monoglycidyl isocyanuric acid. Rate resin is used. For example, when an E glass fiber having a refractive index of 1.562 is used as the glass fiber, the refractive index of diallyl monoglycidyl isocyanuric acid is 1.55, so the refractive index of the resin composition is determined by the refractive index of the glass fiber. In order to approximate it, a resin composition is prepared by selecting a resin having a refractive index higher than that of the glass fiber. When T glass fiber having a refractive index of 1.528 is adopted as the glass fiber, a resin composition is prepared by selecting a resin having a refractive index lower than that of the glass fiber. In preparing the resin composition, the refractive index of the glass fiber is adjusted to n, and the refractive index of the resin composition is adjusted to approximate the refractive index of the glass fiber in the range of n−0.02 to n + 0.02. Is preferred.

  In the present invention, the refractive index of the resin means the refractive index in the state of the cured resin, and is a value tested by ASTM D542.

  The blending amount of the resin used together with diallyl monoglycidyl isocyanuric acid varies depending on the refractive index of the resin and the refractive index of the glass fiber, but is preferably 20 to 50% by mass, more preferably in the total resin components of the resin composition. Is 25-45 mass%.

  The resin used together with diallyl monoglycidyl isocyanuric acid is typically an epoxy resin, and examples thereof include a bisphenol type epoxy resin and an epoxy resin having a 3,4-epoxycyclohexenyl skeleton. A part of the resin may be replaced with a cyanate ester resin.

  Specific examples of bisphenol type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, and trifunctional epoxy resins having a bisphenol A skeleton represented by the following formula (2). be able to.

  In order to lower the viscosity of the varnish of the resin composition, it is desirable to use a liquid bisphenol A type epoxy resin or a liquid bisphenol F type epoxy resin that is liquid at room temperature.

  Specific examples of the epoxy resin having a 3,4-epoxycyclohexenyl skeleton include 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, ε-caprolactone-modified 3,4-epoxycyclohexenylmethyl. -3 ′, 4′-epoxycyclohexanecarboxylate and the like.

  Specific examples of the cyanate ester resin include 2,2-bis (4-cyanatephenyl) propane, bis (3,5-dimethyl-4-cyanatephenyl) methane, 2,2-bis (4-cyanatephenyl) ethane, These derivatives, aromatic cyanate ester compounds, etc. are mentioned. These may be used alone or in combination of two or more.

  The cyanate ester resin has a rigid molecular skeleton, so that a high glass transition temperature can be imparted to the cured product.

  The resin composition is preferably prepared so that the glass transition temperature (Tg) of the cured product is 200 ° C. or higher. When the glass transition temperature is 200 ° C. or higher, the heat resistance of the transparent composite sheet can be increased. The upper limit of the glass transition temperature is not particularly limited, but practically about 280 ° C. is the upper limit of the glass transition temperature.

  In the present invention, the glass transition temperature is a value measured according to the JIS C6481 TMA method.

  In the present invention, a curing initiator (curing agent) can be blended in the resin composition. An organic metal salt can be used as the curing initiator. Specific examples thereof include salts of organic acids such as octanoic acid, stearic acid, acetylacetonate, naphthenic acid and salicylic acid with metals such as Zn, Cu and Fe. These may be used alone or in combination of two or more. Of these, zinc octoate is preferable. By using zinc octoate as the curing initiator, the glass transition temperature of the cured resin can be increased. The content of an organic metal salt such as zinc octoate in the epoxy resin composition is preferably in the range of 0.01 to 0.1 PHR.

  A cationic curing agent can also be used as the curing initiator. By using a cationic curing agent, the transparency of the cured product of the resin composition can be enhanced. Specific examples of the cationic curing agent include aromatic sulfonium salts, aromatic iodonium salts, ammonium salts, aluminum chelates, and boron trifluoride amine complexes. The content of the cationic curing agent in the resin composition is preferably in the range of 0.2 to 3.0 PHR.

  Furthermore, a curing catalyst such as a tertiary amine such as triethylamine or triethanolamine, 2-ethyl-4-imidazole, 4-methylimidazole, or 2-ethyl-4-methylimidazole can also be used as a curing initiator. The content of the curing catalyst in the resin composition is preferably in the range of 0.5 to 5.0 PHR.

  As glass fibers constituting the base material of the transparent composite sheet, fibers of E glass or NE glass are preferably used from the viewpoint of enhancing the impact resistance of the transparent composite sheet. E glass is also referred to as non-alkali glass, and is a glass fiber that is widely used as a glass fiber for resin reinforcement. NE glass is NewE glass. Moreover, the fiber of T glass may be sufficient. T glass has better mechanical and thermal properties than general-purpose E glass.

  The glass fiber is preferably surface-treated with a silane coupling agent usually used as a glass fiber treating agent for the purpose of improving impact resistance. The refractive index of the glass fiber is preferably 1.52 to 1.57, more preferably 1.525 to 1.565. If the refractive index of glass fiber is this range, the transparent composite sheet excellent in visibility can be obtained. As the glass fiber substrate, a glass fiber woven fabric or non-woven fabric can be used.

  And a prepreg can be prepared by impregnating a glass fiber base material with a resin composition, heating and drying. The drying conditions are not particularly limited, but a drying temperature of 100 to 160 ° C. and a drying time of 1 to 10 minutes are preferable.

  Next, one or a plurality of the prepregs are stacked and heated and pressed to cure the resin composition, thereby obtaining a transparent composite sheet. The conditions for the heat and pressure molding are not particularly limited, but a temperature of 150 to 200 ° C., a pressure of 1 to 4 MPa, and a time of 10 to 120 minutes are preferable.

  In the transparent composite sheet obtained as described above, the resin matrix formed of the resin composition containing diallyl monoglycidyl isocyanuric acid has a high glass transition temperature, and a transparent composite sheet excellent in heat resistance is obtained. be able to. Moreover, it is excellent in transparency and the transparent composite sheet which ensured high transparency can be obtained. In this transparent composite sheet, the glass fiber base material content is preferably in the range of 25 to 65% by mass, more preferably in the range of 35 to 60% by mass. If it is this range, while being able to acquire high impact resistance with the reinforcement effect by glass fiber, sufficient transparency can be acquired. Moreover, when there are too many glass fibers, the surface unevenness | corrugation will become large and transparency will also fall. On the other hand, when there are too few glass fibers, the problem that a linear expansion coefficient becomes large will arise.

  In addition, as a base material of glass fiber, in order to obtain high transparency, a substrate in which a plurality of thin ones are stacked can be used. Specifically, a glass fiber substrate having a thickness of 50 μm or less can be used, and two or more glass fiber substrates having a thickness of 50 μm or less can be stacked and used. Although the minimum of the thickness of the base material of glass fiber is not specifically limited, About 10 micrometers is a practical minimum. The number of glass fiber substrates is not particularly limited, but about 20 is the practical upper limit. Thus, when producing a transparent composite sheet using a plurality of glass fiber substrates, each glass fiber substrate is impregnated with a resin composition and dried to produce a prepreg, and a plurality of the prepregs are stacked. A transparent composite sheet can be obtained by heat and pressure molding, but the epoxy resin composition is impregnated and dried in a state in which a plurality of glass fiber substrates are stacked, and a prepreg is produced by heating the prepreg. The transparent composite sheet may be obtained by pressure molding.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all. In addition, the compounding quantity of Table 1 shows a mass part.

The following were used as a compounding component and a base material (glass fiber cloth) of the epoxy resin composition of an Example and a comparative example.
1. Resin component / DA-MGIC, manufactured by Shikoku Kasei Co., Ltd., compound represented by the above formula (1) (diallyl monoglycidyl isocyanuric acid), refractive index 1.55
MA-DGIC, manufactured by Shikoku Kasei Co., Ltd., monoallyl diglycidyl isocyanuric acid / TAIC, manufactured by Nippon Kasei Co., Ltd., triallyl isocyanuric acid / TEPIC, manufactured by Nissan Chemical Co., Ltd., triglycidyl isocyanuric acid / EHPE 3150, Daicel Chemical Industries, Ltd., epoxy resin containing solid 1,2-epoxy-4- (2-oxiranyl) cyclohexane, refractive index 1.51
・ Epiclon 850-S, manufactured by DIC Corporation, liquid bisphenol A type epoxy resin, refractive index 1.59
-Epicron 830-S, manufactured by DIC Corporation, liquid bisphenol F type epoxy resin, refractive index 1.61
・ Techmore VG3101, manufactured by Printec Co., Ltd., trifunctional epoxy resin having a bisphenol A skeleton represented by the above formula (2), refractive index of 1.59
Celoxide 2021P, manufactured by Daicel Chemical Industries, Ltd., 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, refractive index 1.51
2. Curing initiator, Perbutyl I, manufactured by NOF CORPORATION, t-butyl peroxy isopropyl monocarbonate, SI-150L, available from Sanshin Chemical Industry Co., Ltd., cationic curing agent (SbF ₆ ^- sulfonium salt)
3. Base material (glass fiber cloth)
E glass: manufactured by Asahi Kasei Microdevices Corporation, cross type 1037, refractive index 1.562
T glass: manufactured by Nitto Boseki Co., Ltd., cross type 1037, refractive index 1.528
The above resin components are blended in the amounts shown in Table 1, and a curing initiator is blended therein. In Comparative Example 4-5, 50 parts by mass of toluene and 50 parts by mass of methyl ethyl ketone (MEK) are added, and the temperature is 70. A varnish of the resin composition was prepared by stirring and dissolving at 0 ° C.

  Next, a glass fiber cloth having a thickness of 25 μm (Example 4 was T glass, and other examples and comparative examples were E glass) was impregnated with the varnish of the resin composition and heated at 150 ° C. for 2 minutes. Thus, the resin composition was semi-cured to prepare a prepreg.

  Then, two sheets of this prepreg are stacked, set in a press machine, and heated and pressed under conditions of 170 ° C., 2 MPa, 15 minutes to obtain a transparent composite sheet having a resin content of 63 mass% and a thickness of 80 μm. It was.

  For the transparent composite sheets of Examples and Comparative Examples thus obtained, the glass transition temperature (Tg) of the cured product of the resin composition was measured according to the JIS C6481 TMA method, and the haze was measured to be transparent. Sex was evaluated. The haze was measured according to JIS K7136.

  The transparent composite sheet was heated at 170 ° C. for 30 minutes, and the color difference Δb before and after the measurement was measured with a spectrocolorimeter CM-3600d manufactured by Konica Minolta Holdings.

  These results are shown in Table 1.

  From Table 1, in the transparent composite sheets of Examples 1 to 4 using the compound represented by the above formula (1), the glass transition temperature is high, the transparency is high, and the color difference Δb before and after heating is small, and due to heat. Discoloration was greatly suppressed. Moreover, in Example 1-4, since no solvent is required for preparing the varnish of the resin composition, there is no possibility of adversely affecting the global environment due to solvent discharge.

  On the other hand, instead of the compound represented by the above formula (1), a transparent composite sheet was produced in Comparative Example 1-3 using a compound having a triazine ring having a similar structure to the compound represented by the above formula (1). In Comparative Example 4-5 using an epoxy resin containing 1,2-epoxy-4- (2-oxiranyl) cyclohexane, a solvent is required for preparing the varnish of the epoxy resin composition, Moreover, the glass transition temperature of the transparent composite sheet was low, and the color difference Δb before and after heating was large.

DESCRIPTION OF SYMBOLS 1 Transparent composite sheet 4 Glass fiber base material 5 Transparent resin

Claims (6)

  A transparent composite sheet in which a transparent resin is held on a glass fiber substrate, wherein the transparent resin is a cured product of a resin composition containing diallyl monoglycidyl isocyanuric acid.   The transparent composite sheet according to claim 1, wherein the resin composition contains a bisphenol-type epoxy resin or a resin having a 3,4-epoxycyclohexenyl skeleton.   3. The transparent according to claim 2, wherein the bisphenol type epoxy resin is at least one selected from a liquid bisphenol A type epoxy resin, a liquid bisphenol F type epoxy resin, and a trifunctional epoxy resin having a bisphenol A skeleton. Composite sheet.   The transparent composite sheet according to claim 1, wherein the resin composition contains a cyanate ester resin.   The transparent composite sheet according to any one of claims 1 to 4, wherein the glass transition temperature of the transparent resin is 200 ° C or higher.   The transparent composite sheet according to any one of claims 1 to 5, wherein a difference in refractive index between the glass fiber and the transparent resin is 0.02 or less.

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