JP5278742B2 - Transparent sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent sheet that has high heat resistance, surface hardness, refractive index, transparency, and gas barrier properties, satisfies properties with a low coefficient of thermal expansion, is cured by heat and ultraviolet rays, has molding processability while semi-cured, and is completely cured later. <P>SOLUTION: A resin composition (D) containing a condensate (A) obtained by hydrolysis and condensation of a thiol group-containing alkoxysilane: R<SP>1</SP>Si(OR<SP>2</SP>)<SB>3</SB>, a compound (B) having a carbon-carbon double bond, and a compound (C) having an isocyanate group with a ratio [a number of the double bond included in the component (B)/a number of the thiol group in the component (A)] being 0.1-0.8, a ratio [a number of the isocyanate group included in the component (C)/a number of the thiol group in the component (A)] being 0.1-0.8, and a ratio [a number of the carbon-carbon double bond included in the component (B)+a number of the isocyanate group in the component (C)/a number of the thiol group in the component (A)] being 0.9-1.1 is subjected to a two step-curing with heat and ultraviolet rays. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a transparent sheet obtained by two-stage curing of a curable resin composition with heat and ultraviolet rays.

A glass substrate is generally used as a substrate for a flat panel display such as a liquid crystal display or an organic EL display, but there are problems such as being heavy, easily broken, and poor in flexibility and molding processability. By using plastic instead of the glass substrate, it is possible to reduce the weight, impact resistance, and flexibility.

However, because current displays require high display quality such as high color reproducibility, high brightness, high contrast, and screen uniformity, high light transmittance and flatness are also possible for plastics as display substrates. -It is required to have excellent uniformity and colorless transparency. Moreover, in the process of forming the thin film transistor, the alignment film, the transparent electrode, etc. in the manufacturing process of the display and the process of bonding the panel, it is necessary to set the temperature to 150 ° C. or higher. Sex is required. If the heat resistance is not sufficient, the optical characteristics required for the display substrate cannot be sufficiently satisfied due to discoloration, stress or distortion. Furthermore, high processability is also required for the production of flexible displays that have attracted attention in recent years.

In contrast, the present inventors have a thiol group, an organic / inorganic hybrid compound obtained by an ene-thiol reaction between a silsesquioxane having a thiol group and an organic substance having a carbon-carbon double bond. An organic / inorganic hybrid compound obtained by thermally curing silsesquioxane and a compound having an epoxy group or an isocyanate group has been proposed (see Patent Documents 1 and 2). These compounds were easily cured by heat or ultraviolet rays, and had high heat resistance, high surface hardness, high refractive index, high transparency, and the like. However, it did not have sufficient flatness and processability.

On the other hand, by placing glass fibers on a flat metal mold, etc., applying a liquid epoxy resin on the glass fibers, and then applying a reduced pressure condition, impregnating the epoxy resin, and applying heat treatment or UV irradiation. An epoxy resin substrate containing glass fibers by curing an epoxy resin has been proposed (see Patent Document 3). Such a substrate has high heat resistance and improved thermal expansion coefficient, but still does not have sufficient flatness and workability.

JP 2007-291313 A JP 2007-217673 A JP 2004-51960 A

The present invention satisfies various properties such as heat resistance and refractive index, is easily cured by heat and ultraviolet rays, has moldability at an intermediate stage in a semi-cured state, and can be completely cured thereafter. The purpose is to provide a sheet.

As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that a hydrolyzed condensate of thiol group-containing alkoxysilanes, a compound having a carbon-carbon double bond, and a compound having an isocyanate group are blended at a predetermined ratio. The present inventors have found that the above problems can be solved by curing the composition in two steps with heat and ultraviolet rays, and have completed the present invention.

That is, the present invention
General formula (1):
R ¹ Si (OR ² ) ₃ (1)
(In the formula, R ¹ represents a hydrocarbon group having 1 to 8 carbon atoms having at least one thiol group or an aromatic hydrocarbon group having at least one thiol group, and R ² represents a hydrogen atom or 1 carbon atom) A condensate (A) (hereinafter referred to as (A)) obtained by hydrolysis and condensation of a thiol group-containing alkoxysilane (a1) represented by -8 hydrocarbon groups or aromatic hydrocarbon groups. Component)), compound (B) containing two or more allyl groups (hereinafter referred to as component (B)), and compound (C) having an isocyanate group (hereinafter referred to as component (C)) [ {Number of double bonds contained in component (B)} / {number of thiol groups in component (A)}] is 0.1 to 0.8, [isocyanate group contained in component (C) Number} / (number of thiol groups in component (A)}] is 0.1 0.8, [{number of carbon-carbon double bonds contained in component (B) + number of isocyanate groups in component (C)} / {number of thiol groups in component (A)}] is 0 A transparent sheet obtained by two-stage curing of a resin composition (D) (hereinafter referred to as “component (D)”) contained in a ratio of .9 to 1.1 with heat and ultraviolet rays.
The present invention is also a transparent sheet in which the two-stage curing is performed by thermally curing the resin composition (D) to a semi-cured state, molding, and then curing with ultraviolet rays.
Further, the present invention is also a transparent sheet in which the two-stage curing is a method in which the resin composition (D) is ultraviolet-cured into a semi-cured state, molded, and then thermally cured.
Moreover, this invention is also the said transparent sheet produced on the transparent support body.
Furthermore, the present invention is also a transparent sheet obtained by impregnating the above-mentioned resin composition (D) into a glass cloth, followed by two-stage curing with heat and ultraviolet rays.

According to the present invention, while satisfying various properties of high heat resistance, surface hardness, refractive index, transparency, gas barrier property and low coefficient of thermal expansion, it is easily cured by heat or ultraviolet rays, and is in a semi-cured state. It is possible to provide a transparent sheet that has moldability at an intermediate stage and can be completely cured thereafter. The transparent sheet of the present invention is a light guide plate, polarizing plate, liquid crystal panel, EL panel, PDP panel, OHP film, color filter, optical disk substrate, lens, prism sheet, diffuser plate, backlight, waveguide, electronic paper, touch panel, etc. It is useful as a transparent substrate.

The component (A) used in the present invention has the general formula (1):
R ¹ Si (OR ² ) ₃ (1)
(In the formula, R ¹ represents a hydrocarbon group having 1 to 8 carbon atoms having at least one thiol group, or an aromatic hydrocarbon group having at least one thiol group, and R ² represents a hydrogen atom, having 1 to 1 carbon atoms. 8 is a compound obtained by hydrolysis and condensation of a thiol group-containing alkoxysilane (a1) represented by formula (8) or an aromatic hydrocarbon group.

Specific examples of the thiol group-containing alkoxysilanes (a1) (hereinafter referred to as the component (a1)) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3 -Mercaptopropyltributoxysilane, 1,4-dimercapto-2- (trimethoxysilyl) butane, 1,4-dimercapto-2- (triethoxysilyl) butane, 1,4-dimercapto-2- (tripropoxysilyl) Butane, 1,4-dimercapto-2- (tributoxysilyl) butane, 2-mercaptomethyl-3-mercaptopropyltrimethoxysilane, 2-mercaptomethyl-3-mercaptopropyltriethoxysilane, 2-mercaptomethyl-3- Mercaptopropyltripro Xysilane, 2-mercaptomethyl-3-mercaptopropyltributoxysilane, 1,2-dimercaptoethyltrimethoxysilane, 1,2-dimercaptoethyltriethoxysilane, 1,2-dimercaptoethyltripropoxysilane, 1, Examples include 2-dimercaptoethyltributoxysilane, and the exemplary compounds can be used alone or in appropriate combination. Among the exemplified compounds, 3-mercaptopropyltrimethoxysilane is particularly preferable because of high reactivity of hydrolysis reaction and easy availability.

In addition to the component (a1), trialkylalkoxysilanes such as trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, triethylethoxysilane, triphenylmethoxysilane, triphenylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxy Dialkyl dialkoxysilanes such as silane, diethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane, methyltrimethoxysilane Methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, Alkyltrialkoxysilanes such as rutriethoxysilane, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetramethoxytitanium, tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, etc. Metal alkoxides (a2) (hereinafter referred to as component (a2)) such as tetraalkoxyzirconiums such as tetraalkoxytitaniums, tetraethoxyzirconium, tetrapropoxyzirconium, and tetrabutoxyzirconium can be used. (A2) A component can be used individually or in combination of 2 or more types. Among these, the crosslinking density of the component (A) can be adjusted by using trialkylalkoxysilanes, dialkyldialkoxysilanes, and tetraalkoxysilanes. By using alkyltrialkoxysilanes, the amount of thiol groups contained in component (A) can be adjusted. By using tetraalkoxy titanium or tetraalkoxy zirconium, the refractive index of the finally obtained transparent sheet can be increased.

When the component (a1) and the component (a2) are used in combination, {number of moles of thiol group contained in the component (a1)} / {total number of moles of component (a1) and component (a2)} (per molecule) The average number of thiol groups contained is preferably 0.2 or more. When it is less than 0.2, the number of thiol groups contained in the component (A) to be obtained is reduced, so that the thermosetting property and the ultraviolet curable property are lowered, and the physical properties such as the hardness of the transparent sheet are improved. Tend to be insufficient. Also, {the total number of moles of each alkoxy group contained in the components (a1) and (a2)} / {the total number of moles of the components (a1) and (a2)} (molar ratio: alkoxy contained per molecule The average number of groups) is preferably 2.5 or more and 3.5 or less, and more preferably 2.7 or more and 3.2 or less. When it is less than 2.5, the crosslinking density of the obtained component (A) is low, and the heat resistance of the transparent sheet tends to decrease. Moreover, when it exceeds 3.5, when manufacturing (A) component, it exists in the tendency which becomes easy to gelatinize.

The component (A) used in the present invention can be obtained by condensing the component (a1) alone or in combination with the component (a2) and hydrolyzing them. By the hydrolysis reaction, the alkoxy group contained in the component (a1) or the component (a2) becomes a hydroxyl group, and alcohol is by-produced. The amount of water required for the hydrolysis reaction is {number of moles of water used in the hydrolysis reaction} / {total number of moles of each alkoxy group contained in the components (a1) and (a2)} (molar ratio). 4 or more and 10 or less, and preferably 0.5 or more and 2 or less. When it is less than 0.4, there is an alkoxy group remaining without being hydrolyzed in the component (A), which is not preferable. On the other hand, when it exceeds 10, the amount of water to be removed in the subsequent condensation reaction (dehydration reaction) increases, so that the production time becomes longer, which is economically disadvantageous.

In addition, when (a2) component is used together with tetraalkoxytitanium, tetraalkoxyzirconium, etc., particularly metal alkoxides with high hydrolyzability and condensation reactivity, hydrolysis and condensation reaction proceed rapidly, and the system May gel. In this case, gelation can be avoided by adding the component (a2) after the hydrolysis reaction of the component (a1) is completed and all water has been consumed.

The catalyst used for the hydrolysis reaction is not particularly limited, and a conventionally known hydrolysis catalyst can be arbitrarily used. Of these, formic acid is preferred because it has high catalytic activity and also functions as a catalyst for the subsequent condensation reaction. The amount of formic acid added is preferably 0.1 to 25 parts by weight and more preferably 1 to 10 parts by weight with respect to 100 parts by weight as a total of the components (a1) and (a2). When the amount is more than 25 parts by weight, the stability of the obtained component (D) tends to decrease, and even if formic acid can be removed in a subsequent step, the removal amount tends to increase. On the other hand, when the amount is less than 0.1 parts by weight, the reaction does not substantially proceed or the reaction time tends to be long. Although reaction temperature and time can be arbitrarily set according to the reactivity of the component (a1) or the component (a2), it is usually about 0 to 100 ° C., preferably about 20 to 60 ° C., about 1 minute to 2 hours. The hydrolysis reaction can be carried out in the presence or absence of a solvent. The type of the solvent is not particularly limited, and one or more arbitrary solvents can be selected and used, but it is preferable to use the same solvent as that used in the condensation reaction described later. When the reactivity of the component (a1) or the component (a2) is low, it is preferable to carry out without a solvent.

The hydrolysis reaction is carried out by the above method, but {number of moles of hydroxyl groups formed by hydrolysis} / {total number of moles of each alkoxy group contained in components (a1) and (a2)} (molar ratio) is 0. It is preferable to make it progress so that it may become 0.5 or more, and it is still more preferable to adjust to 0.8 or more.

In the condensation reaction, water is by-produced between the hydroxyl groups, and alcohol is by-produced between the hydroxyl group and the alkoxy group to form a siloxane bond. A conventionally known dehydration condensation catalyst can be arbitrarily used for the condensation reaction. As described above, formic acid is preferable because it has high catalytic activity and can be used as a catalyst for hydrolysis reaction. The reaction temperature and time can be arbitrarily set depending on the reactivity of the components (a1) and (a2), but are usually about 40 to 150 ° C., preferably 60 to 100 ° C., and about 30 minutes to 12 hours. .

The condensation reaction is carried out by the above method. {Total mole number of unreacted hydroxyl group and unreacted alkoxy group} / {Total mole number of each alkoxy group contained in component (a1) or component (a2)} (molar ratio) ) Is preferably 0.3 or less, and more preferably 0.2 or less. When 0.3 is exceeded, the unreacted hydroxyl group and alkoxy group undergo a condensation reaction during storage of component (D) to gel, or after curing, a condensation reaction occurs to generate volatile matter and cracks occur. This is not preferable because it tends to impair the performance.

The condensation reaction is preferably carried out by diluting the solvent so that the concentration of the component (a1) (or both when the component (a2) is used in combination) is about 2 to 80% by weight. It is more preferable. It is preferable to use a solvent having a boiling point higher than that of water and alcohol generated by the condensation reaction because these can be distilled off from the reaction system. When the concentration is less than 2% by weight, the component (A) contained in the component (D) to be obtained is decreased, which is not preferable. When it exceeds 80% by weight, the molecular weight of the component (A) that is gelled or generated during the reaction tends to be too large, and the storage stability of the resulting component (D) tends to be poor. As the solvent, one or more arbitrary solvents can be selected and used. It is preferable to use a solvent having a boiling point higher than that of water and alcohol produced by the condensation reaction because these can be distilled off from the reaction system. Moreover, (B) component can also be used as a part of solvent.

After completion of the condensation reaction, it is preferable to remove the used catalyst because the stability of the finally obtained component (D) is improved. The removal method can be appropriately selected from various known methods depending on the catalyst used. For example, when formic acid is used, it can be easily removed by a method such as heating to above the boiling point or depressurization after completion of the condensation reaction, and formic acid is also preferred in this respect.

The carbon-carbon double bond of the component (B) is disadvantageous in that the functional groups having a carbon-carbon double bond are polymerized in preference to the reaction between the functional group having a carbon-carbon double bond and a thiol group. It is preferable to use one having low radical polymerizability so as not to occur. Examples of such component (B) include compounds having one or more allyl groups. The compounds containing one allyl group include cinnamic acid, monoallyl cyanurate, monoallyl isocyanurate, pentaerythritol monoallyl ether, trimethylolpropane monoallyl ether, glycerin monoallyl ether, bisphenol A monoallyl ether, bisphenol. Examples thereof include F monoallyl ether, ethylene glycol monoallyl ether, diethylene glycol monoallyl ether, triethylene glycol monoallyl ether, propylene glycol monoallyl ether, dipropylene glycol monoallyl ether, and tripropylene glycol monoallyl ether. Compounds containing two allyl groups include diallyl phthalate, diallyl isophthalate, diallyl cyanurate, diallyl isocyanurate, pentaerythritol diallyl ether, trimethylolpropane diallyl ether, glyceryl diallyl ether, bisphenol A diallyl ether, bisphenol F diallyl ether Ethylene glycol diallyl ether, diethylene glycol diallyl ether, triethylene glycol diallyl ether, propylene glycol diallyl ether, dipropylene glycol diallyl ether, tripropylene glycol diallyl ether, and the like. Examples of the compound containing three or more allyl groups include triallyl isocyanurate, pentaerythritol triallyl ether, pentaerythritol tetraallyl ether, trimethylolpropane triallyl ether, and the like. These compounds can be used either alone or in combination. Among these, compounds having only one carbon-carbon double bond in the molecule do not cause cross-linking between molecules, so that the effect of improving the physical properties such as heat resistance and surface hardness of the transparent sheet is insufficient. Because of the tendency, compounds having two or more carbon-carbon double bonds in the molecule are preferable, and among them, triallyl isocyanurate, diallyl phthalate, and pentaerythritol triallyl ether are particularly preferable.

Further, as the component (B), those having a higher molecular weight than the compound having an allyl group can also be used. Component (D) using a high molecular weight component (B) tends to improve the flexibility of the resulting cured product. Moreover, generally there exists a tendency for radical polymerizability to become low, and it can use preferably also from such a viewpoint. Examples of the high molecular weight compound include a copolymer composed of methylallylsiloxane and dimethylsiloxane, a copolymer composed of epichlorohydrin and allylglycidyl ether (Daiso Co., Ltd .: trade name “Epichromer”, Nippon Zeon Co., Ltd .: Commodity Name "Gechron", etc.), allyl group-terminated polyisobutylene polymer (Kaneka Co., Ltd .: trade name "Epion"), urethane acrylate (produced by Arakawa Chemical Industry Co., Ltd .: trade name "Beam Set 550B") and the like. These compounds can be used alone or in combination of two or more.

Moreover, the (C) component used by this invention is not specifically limited, The compound which has a conventionally well-known isocyanate group can be used suitably. As the diisocyanate compound, for example, various known aromatic, aliphatic or alicyclic diisocyanates can be used. More specifically, for example, 1,5-naphthylene diisocyanate, 4,4′- Diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane -1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene dii Cyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,3 Examples thereof include bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimerisocyanate obtained by converting a carboxyl group of dimer acid into an isocyanate group. These compounds can be used alone or in combination of two or more. Among the exemplified compounds, isophorone diisocyanate is particularly preferable because the finally obtained transparent sheet is excellent in colorless transparency, heat resistance and the like and is easily available.

As the component (C), one having a higher molecular weight than the above compound can be used. According to the component (D) using a high molecular weight, the flexibility of the obtained transparent sheet tends to be improved. Examples of the high molecular weight product include diisocyanate-modified products of polyols such as polycarbonate diol and polyester diol, polymeric MDI (Mitsui Takeda Chemical Co., Ltd .: trade name “Cosmonate M”, etc.), polyisocyanurate type HDI (Nippon Polyurethane) Kogyo Co., Ltd .: trade name “Coronate HX” etc.). These compounds can be used alone or in combination of two or more. Among the exemplified compounds, polyisocyanurate type HDI is particularly preferable because the finally obtained transparent sheet is excellent in colorless transparency, heat resistance and the like and is easily available.

Further, methacryloyloxyethyl isocyanate (trade name “Karenz MOI” manufactured by Showa Denko KK) and acryloyloxyethyl isocyanate (product name “Karenz AOI” manufactured by Showa Denko KK) as high molecular weight compounds are contained in one molecule. A compound in which a double bond and an isocyanate group are present simultaneously can also be used. When such a compound is used, it can be considered that the (B) and (C) components are contained at the same time, and it is used in consideration of the number of double bonds and the number of isocyanate groups contained in the molecule. The amount needs to be determined.

Further, when the component (C) is used, a conventionally known urethanization catalyst can be used. For example, organic tin compounds such as dibutyltin dilaurate and tin octylate, 1,8-diaza-bicyclo [5.4.0] undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethyl) And tertiary amines such as (aminomethyl) phenol. The urethanization catalyst is preferably used in a proportion of 0.01 to 5 parts by weight per 100 parts by weight of component (D).

The concentrations of the effective (A) component, the (B) component, and the (C) component in the component (D) can be appropriately determined according to the use, and a solvent can be blended as necessary. The solvent only needs to be non-reactive with the component, and various conventionally known solvents can be appropriately selected and used. When the component (D) is used by coating, it may be diluted with a solvent to obtain a desired viscosity. When the (D) component is cured to a thick film of 1 mm or more, the total concentration of the (A) component, the (B) component, and the (C) component is preferably 90% by weight or more in the (D) component. More preferably, the content is 95% by weight or more. The total concentration can be obtained by calculation based on the concentrations of the components (A), (B) and (C) and the amount of the solvent added during the preparation of the component (D), and is included in the component (D). It can also be obtained by heating for about 2 hours above the boiling point of the solvent and by weight change before and after heating. When the component (D) is cured to a thick film of 1 mm or more, if it is less than 90% by weight, foaming occurs at the time of curing and molding, or a solvent remains in the transparent sheet, which deteriorates the physical properties of the transparent sheet. Tend. In addition, since the solvent is indispensable when synthesizing the component (A), the solvent should be volatilized after the reaction so that the non-volatile content is 90% by weight or more when used for this purpose. That's fine. Moreover, after preparing (D) component, the used solvent can be volatilized and the total density | concentration of an effective (A) component, (B) component, and (C) component can also be raised.

The component (D) contains the component (A), the component (B), and the component (C). Each component contained in the component (D) has a [{number of double bonds contained in the component (B)} / {number of thiol groups in the component (A)}] of 0.1 to 0.00. 8, [{number of isocyanate groups in component (C)} / {number of thiol groups in component (A)}] is 0.1 to 0.8; [{(B) component included in double The number of bonds + number of double bonds contained in component (C)} / {number of thiol groups in component (A)}] is contained in a ratio of 0.9 to 1.1.
[{Number of double bonds contained in component (B) + number of isocyanate groups contained in component (C))} / {number of thiol groups in component (A)} is less than 0.9 In some cases, the thiol group remains and may cause malodor due to its decomposition. In the case of 1.1 or more, carbon-carbon double bonds and isocyanate groups remain after curing, and the weather resistance tends to be lowered.
When [{number of double bonds contained in component (B)} / {number of thiol groups in component (A)}] exceeds 0.8, curing occurs when UV curing is the first step. When the thermosetting is performed in the first stage, the amount of unreacted component (B) is excessively increased in the semi-cured product, so that molding processability may be lost in all cases. When the ratio is less than 0.1, the component (C) is inevitably [{number of isocyanate groups in the component (C)} / {number of thiol groups in the component (A)}] is 0.8. When the ultraviolet curing is the first stage, the unreacted (C) component is too much in the semi-cured product. Therefore, when the thermal curing is the first stage, the curing proceeds. In any case, molding processability may be lost.
When {the number of isocyanate groups in component (C)} / {the number of thiol groups in component (A))} exceeds 0.8, when UV curing is the first step, Since there are too many unreacted components (C), when thermosetting is the first stage, curing proceeds too much, and in any case, molding processability may be lost. When the ratio is less than 0.1, the component (B) is inevitably [{number of double bonds in component (B)} / {number of thiol groups in component (A)}] is 0.8. When UV curing is the first step, curing proceeds too much, and when heat curing is the first step, unreacted component (B) increases in the semi-cured product. Therefore, in any case, molding processability may be lost.

Further, the component (D) can be blended with the component (a1) and / or a hydrolyzate thereof (hereinafter also referred to as the component (E)) depending on the application. As the component (E), the component (a1) used in the synthesis of the component (A) can be used as it is, or a hydrolyzate thereof can be used in combination. When a transparent sheet obtained by two-stage curing of the component (D) containing the component (E) is used as a coating agent for an inorganic substrate such as glass or metal, there is an advantage that adhesion can be further improved. (E) It is preferable that the compounding quantity of a component is about 0.1-20 weight part with respect to 100 weight part of (D) component. When the amount is less than 0.1 part by weight, the effect of improving the adhesion of the transparent sheet to the inorganic base material tends to be insufficient. Moreover, when it exceeds 20 weight part, since the volatile matter at the time of (E) component hydrolyzing and a condensation reaction increases, (D) component foams at the time of hardening, a curvature and a crack generate | occur | produce, and it is obtained. The transparent sheet tends to become brittle. As such a component (E), 3-mercaptopropyltrimethoxysilane is particularly preferable in terms of the effect of improving adhesion.

In addition, the component (D) can be mixed with the metal alkoxides and / or hydrolysates thereof (hereinafter collectively referred to as the component (F)) as the component (a2) depending on the application. As the component (F), the metal alkoxides used in the synthesis of the component (A) can be used as they are, their hydrolysates can be used, or these can be used in combination. By using the component (D) containing the component (F), the refractive index of the obtained transparent sheet can be adjusted. When the transparent sheet is used as a coating agent having a high refractive index, alkoxytitaniums and alkoxyzirconiums are suitable as the component (F). (F) It is preferable that the compounding quantity of a component is about 0.1-20 weight part with respect to 100 weight part of (D) component. If it is less than 0.1 part by weight, the refractive index improving effect tends to be insufficient. In addition, when the amount exceeds 20 parts by weight, the amount of volatile components when the component (F) undergoes hydrolysis and condensation reaction increases, so that the component (D) foams during curing, warps and cracks occur, The resulting transparent sheet tends to be brittle.

Furthermore, the component (D) includes plasticizers, weathering agents, antioxidants, heat stabilizers, lubricants, antistatic agents, potentiometers, and the like within the range that does not impair the effects of the present invention. You may mix | blend a whitening agent, a coloring agent, a electrically conductive agent, a mold release agent, a surface treating agent, a viscosity modifier, a filler, etc.

In the transparent sheet of the present invention, the component (D) is poured into a container or a flat plate, preferably a container subjected to mold release treatment such as Teflon (registered trademark) coating, heated to dry the solvent, and then heated and irradiated in two stages. It is obtained by curing. As a method of performing the two-stage curing, there is a method in which the thermosetting is performed in the first stage and then the UV curing is performed in the second stage, the UV curing is performed in the first stage, and the thermosetting is performed in the second stage. It is done.

The two-stage curing is preferably one in which the component (D) is thermally cured to a semi-cured state, molded and then UV-cured. The semi-cured state means a state in which the component (D) is reacted with only the component (A) and the component (C) by heat. Specifically, the elastic modulus at the temperature at which the molding process is performed is 10 ^It means a state of ⁵ to 10 ⁷ Pa. Since such a semi-cured state during curing is not sufficiently cured, various molding processes are possible. As a method of molding processing, for example, after coating the flat plate with the component (D), it is made into a semi-cured state by thermosetting, the flat plate is bent while preventing the component (D) from flowing from the flat plate, and the ultraviolet rays are kept in the bent state. And a method of preparing a transparent sheet in close contact with the curved surface by completely curing. The first stage curing temperature and heating time by heat are appropriately determined in consideration of the types of components (A), (B) and (C) used, the type of solvent, the thickness of the transparent sheet, and the like. However, it is usually preferable to set the temperature at about 20 to 150 ° C. for about 1 minute to 24 hours. In the second stage of curing with ultraviolet rays after the molding process, the components (A) and (B) are reacted by irradiating ultraviolet rays for about 1 minute to 6 hours to completely advance the curing.

The two-stage curing is preferably one in which the component (D) is UV cured to be in a semi-cured state, molded and then thermally cured. The semi-cured state means a state in which the component (D) is reacted with only the component (A) and the component (B) by heat. Specifically, the elastic modulus at the temperature at which molding is performed is 10 ^It means a state of ⁵ to 10 ⁷ Pa. Since such a semi-cured state during curing is not sufficiently cured, various molding processes are possible. As a method of molding, for example, after coating the flat plate with the component (D), the plate is made into a semi-cured state by ultraviolet curing, and the flat plate is bent while preventing the component (D) from flowing from the flat plate. And a method of preparing a transparent sheet in close contact with the curved surface by completely curing. When a solvent is used as the component (D), it is preferable to dry the solvent before the ultraviolet irradiation and use it as a substantially solvent-free material. The curing time of the first stage with ultraviolet rays is appropriately determined in consideration of the types of the components (A), (B) and (C) used, the type of solvent, the thickness of the transparent sheet, etc. Is preferably about 1 hour. In addition, in the second stage heat curing after the molding process, the curing temperature and heating time take into account the type of component (B) or (C) used, the type of solvent, the thickness of the transparent sheet, and the like. Depending on the circumstances, it is usually determined at about 20 to 150 ° C. for 1 minute to 24 hours to completely remove the residual solvent and further advance the curing reaction.

The transparent sheet of the present invention is preferably prepared on a transparent support. The component (D) is produced on a desired transparent support, and a transparent sheet produced on the transparent support can be obtained by two-stage curing with heat or ultraviolet rays. The production method of the component (D) on the transparent support is not particularly limited, and a conventionally known method can be used.

As the transparent support, inorganic substrates such as glass, iron, aluminum, copper, ITO, polyethylene resin (PE), polypropylene resin (PP), polyethylene terephthalate resin (PET), polyethylene naphthalate resin (PEN), Various known materials such as an organic substrate such as polymethyl methacrylate resin (PMMA), polystyrene resin (PSt), polycarbonate resin (PC), and acrylonitrile-butylene-styrene resin (ABS) can be appropriately selected and used. When coating on an inorganic substrate, if the adhesion is insufficient, it is preferable to use the component (E) in combination as described above. Moreover, when coating to an organic base material, when adhesiveness is insufficient, it is preferable to use (D) component together as mentioned above. Further, by diluting the component (D) with a solvent, the viscosity is lowered and coating properties such as easy coating can be improved. For the light guide plate, polarizing plate, liquid crystal panel, EL panel, PDP panel, OHP film, optical fiber, color filter, optical disk substrate, lens, and liquid crystal cell by coating the above component (D) and curing it in two steps A transparent sheet as a coating layer can be formed on a plastic substrate, a prism or the like.

Moreover, when the refractive index of a transparent sheet is higher than a base material, an antireflection effect can be provided. In the production of the component (A), the component (a2) can be used together with the component (a1), or the component (D) containing the metal alkoxide as the component (F) can be cured in two steps as described above. The refractive index of the transparent sheet can be improved. Therefore, anti-reflection effect is applied to the coating layer applied to the light guide plate, polarizing plate, liquid crystal panel, EL panel, PDP panel, OHP film, optical fiber, color filter, optical disk substrate, lens, plastic substrate for liquid crystal cell, prism. In the case of imparting, it is preferable to add an appropriate amount of the component to the component (D).

(Application to transparent substrate)
A transparent sheet obtained by impregnating the component (D) into a glass cloth (base material) and then two-stage curing with heat and ultraviolet rays is also one aspect of the present invention. Such a transparent sheet can be used as a transparent substrate in close contact with the substrate.

Various known materials can be appropriately selected and used as the glass cloth. As the glass cloth, various kinds of fabrics obtained from various known glass fibers (strands composed of E glass, C glass, T glass, ECR glass, etc., yarn, roving, etc.) can be used. Glass cloth is particularly preferred because it is inexpensive and has excellent availability.

The method for impregnating the component (D) into the glass cloth is not particularly limited, and various known methods can be employed, and a coating method may be employed. Moreover, in order to make the transparent substrate obtained colorless and transparent, it is preferable to make the difference in refractive index between the transparent sheet obtained from the component (D) and the glass cloth within 0.02, preferably within 0.01. More preferably, the same is more preferable. Moreover, the impregnation property to a glass cloth can also be improved more by solvent diluting (D) component. In addition, the usage-amount of (D) component with respect to glass cloth can be suitably determined according to the use of the transparent substrate obtained, and is normally about 20-500 weight part per 100 weight part of glass cloth. Moreover, the thickness of the transparent substrate obtained can also be suitably determined according to this use, and is normally set to 20 μm to 1 mm. The transparent substrate obtained by impregnating the glass cloth with the component (D) as described above and two-stage curing with heat and ultraviolet rays is excellent in transparency and heat resistance, has a low coefficient of thermal expansion, and has a high gas barrier property. It is suitable for producing a coating layer on a light guide plate, a polarizing plate, a liquid crystal panel, an EL panel, a PDP panel, a color filter, an optical disk substrate, a liquid crystal cell plastic substrate, a flexible display substrate, and the like.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In each example, parts and% are based on weight unless otherwise specified.

Production Example 1 (Production of condensate (A-1))
In a reactor equipped with a stirrer, a condenser, a water separator, a thermometer, and a nitrogen inlet, 3400 parts of 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name “KBM-803”), ion 936 parts of exchange water ([number of moles of water used for hydrolysis reaction] / [number of moles of alkoxy groups contained in component (a1)] (molar ratio) = 1.0), 68 parts of 95% formic acid were charged at room temperature. For 30 minutes. During the reaction, the temperature increased by a maximum of 35 ° C. due to exotherm. After the reaction, 5670 parts of toluene was charged and heated. When the temperature was raised to 71 ° C., methanol generated by hydrolysis and a part of toluene began to be distilled off. The temperature was raised to 75 ° C. over 2 hours, and the water was distilled off by condensation reaction. Furthermore, after making it react at 75 degreeC for 1 hour, it pressure-reduced at 70 degreeC-200 hPa, and distilled some remaining toluene, methanol, water, and formic acid. Furthermore, it reduced pressure at 70 degreeC-7 hPa, and distilled off toluene, and obtained 2330 parts of condensates (A-1). [Mole number of unreacted hydroxyl group and alkoxy group] / [Mole number of alkoxy group contained in component (a1)] (molar ratio) was 0.12, and the concentration was 99.0%. The concentration of the thiol group in the condensate (A-1) was 7.41 mmol / g.

Production Example 2 (Production of condensate (A-2))
In the same reactor as in Production Example 1, 4610 parts of 3-mercaptopropyltrimethoxysilane, 2240 parts of methyltrimethoxysilane (manufactured by Tama Chemical Co., Ltd .: trade name “methyltrimethoxysilane”) ([component (a1) Number of moles of thiol group contained] / [total number of moles of component (a1) and component (a2)] = 0.63, [total number of moles of alkoxy groups contained in component (a1) and component (a2)] / [Total number of moles of component (a1) and component (a2)] = 3), 2160 parts of ion-exchanged water ([number of moles of water used for hydrolysis reaction] / [included in component (a1) and component (a2) The total number of moles of each alkoxy group] (molar ratio) = 1.0) and 136 parts of 95% formic acid were charged and subjected to a hydrolysis reaction at room temperature for 30 minutes. During the reaction, the temperature rose by a maximum of 37 ° C. due to exotherm. After the reaction, 11400 parts of toluene was charged and heated. When the temperature was raised to 72 ° C., part of methanol and toluene generated by hydrolysis began to be distilled off. The temperature was raised to 75 ° C. over 1 hour, and the water was distilled off by condensation reaction. Furthermore, after making it react at 75 degreeC for 1 hour, it pressure-reduced at 70 degreeC-200 hPa, and distilled some remaining toluene, methanol, water, and formic acid. Furthermore, it reduced pressure at 70 degreeC-7 hPa, and distilled toluene, and 4310 parts of condensates (A-2) were obtained. [Mole number of unreacted hydroxyl group and alkoxy group] / [Total number of moles of each alkoxy group contained in component (a1) and component (a2)] (molar ratio) is 0.10, and the concentration is 99.2%. there were. Moreover, the density | concentration of the thiol group of a condensate (A-2) was 5.43 mmol / g.

Production Example 3 (Production of condensate (A-3))
In the same reactor as in Production Example 1, 4700 parts of 3-mercaptopropyltrimethoxysilane, 2370 parts of phenyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name “KBM-103”) (in [component (a1)) Number of moles of thiol group contained] / [total number of moles of component (a1) and component (a2)] = 0.67, [total number of moles of alkoxy groups contained in component (a1) and component (a2)] / [Total number of moles of component (a1) and component (a2)] = 3), 1940 parts of ion-exchanged water ([number of moles of water used in hydrolysis reaction] / [included in component (a1) and component (a2) The total number of moles of each alkoxy group] (molar ratio) = 1.0) and 140 parts of 95% formic acid were charged and subjected to a hydrolysis reaction at room temperature for 30 minutes. During the reaction, the temperature rose by a maximum of 40 ° C. due to exotherm. After the reaction, 11800 parts of toluene was charged and heated. When the temperature was raised to 71 ° C., part of methanol and toluene generated by hydrolysis began to be distilled off. The temperature was raised to 75 ° C. over 1 hour, and the water was distilled off by condensation reaction. Furthermore, after making it react at 75 degreeC for 1 hour, it pressure-reduced at 70 degreeC-200 hPa, and distilled some remaining toluene, methanol, water, and formic acid. Furthermore, it reduced pressure at 70 degreeC-7hPa, and distilled toluene, and 4950 parts of condensates (A-3) were obtained. [Mole number of unreacted hydroxyl group and alkoxy group] / [Total mole number of each alkoxy group contained in component (a1) and component (a2)] (molar ratio) is 0.10, and the concentration is 98.5%. there were. Moreover, the density | concentration of the thiol group of a condensate (A-3) was 4.83 mmol / g.

Formulation Examples 1-6 (Production of heat-ultraviolet two-stage curable composition)
For 39.4 parts of the condensate (A-1) obtained in Production Example 1, triallyl isocyanurate (TAIC, manufactured by Nippon Kasei Co., Ltd .: trade name “TAIC”, carbon-carbon as component (B) The concentration of double bonds is 12.0 mmol / g) 18.9 parts ([number of moles of carbon-carbon double bonds contained in component (B)] / [number of moles of thiol groups contained in component (A) (Molar ratio) = 0.70), polyfunctional isocyanate as component (C) (hereinafter Coronate HX, manufactured by Nippon Polyurethane Co., Ltd .: trade name “Coronate HX”, concentration of isocyanate group is 5.00 mmol / g ) 11.8 parts ([number of moles of isocyanate group contained in component (C)] / [number of moles of thiol group contained in component (A)] (molar ratio) = 0.28) (([(B) Number of moles of carbon-carbon double bond contained in the component] + (C) Number of moles of isocyanate group contained in component]) / [Mole number of thiol group contained in component (A)] (molar ratio) = 0.98), dibutyltin dilaurate (hereinafter referred to as U-) as a thermosetting catalyst 100, Nitto Kasei Co., Ltd .: trade name “Neostan U-100”) 0.14 parts, hydroxycyclohexyl phenyl ketone as photocuring catalyst (hereinafter Irg184, Ciba Japan Co., Ltd .: trade name “Irgacure 184”) 0 .14 parts, 29.6 parts of ethylene glycol dimethyl ether (hereinafter DMG, Nippon Emulsifier Co., Ltd .: trade name “DMG”) as a diluting solvent was disposed to obtain a heat-ultraviolet two-stage curable composition (D-1). . Similarly, the condensates (A-1 to 3) obtained in Production Examples 1 to 3 were used to obtain heat-ultraviolet two-stage curable compositions (D-2 to 6) according to Tables 1 and 2. In Table 1, BS-550B: polyfunctional urethane acrylate (Arakawa Chemical Industries, Ltd .: trade name “Beam Set 550B”, concentration of carbon-carbon double bond is 2.25 mmol / g), IPDI: isophorone diisocyanate (Manufactured by Sumika Bayer Urethane Co., Ltd .: trade name “Desmodur I”, isocyanate group concentration is 9.01 mmol / g).

Formulation Example 7 (Production of heat-ultraviolet two-stage curable composition)
Instead of the condensate (A), trimethylolpropane tris (3-mercaptopropionate) (hereinafter TMMP, manufactured by Sakai Chemical Industry Co., Ltd .: trade name “TMMP”, the concentration of the thiol group is 7.52 mmol / g. ) And TMMP 37.4 parts, TAIC 16.2 parts as component (B) ([number of moles of carbon-carbon double bond contained in component (B)] / [included in component (A) Mole number of thiol group] (molar ratio) = 0.60), as component (C) 16.1 parts of coronate HX (mole number of isocyanate group contained in component (C) / included in component (A) Number of moles of thiol group] (molar ratio) = 0.38) ([number of moles of carbon-carbon double bond contained in component (B)] + [number of moles of isocyanate group contained in component (C) ]) / [Thiol group contained in component (A) Mole number] (molar ratio) = 0.98), U-100 0.14 part as a thermosetting catalyst, 0.14 part Irg184 as a photocuring catalyst, 30.0 parts DMG as a diluting solvent, and heat -It was set as the ultraviolet two-stage curable composition (d-1).

Formulation Example 8 (Production of UV curable composition)
For 43.5 parts of the condensate (A-1) obtained in Production Example 1, 26.8 parts of TAIC as component (B) ([number of moles of carbon-carbon double bonds contained in component (B)] / [Number of moles of thiol groups contained in component (A)] (molar ratio) = 1.00), 0.14 part of Irg184 as a photocuring catalyst, and ultraviolet curable composition (d-2) did.

Formulation Example 9 (Production of thermosetting composition)
For 28.3 parts of the condensate (A-1) obtained in Production Example 1, 41.9 parts of coronate HX as component (C) ([number of moles of isocyanate groups contained in component (C)] / [( A) The number of moles of thiol groups contained in the component] (molar ratio) = 1.00), 0.14 part of U-100 as the catalyst for thermosetting, and 29.7 parts of DMG as the diluting solvent, thermosetting It was set as the composition (d-3).

In the table, (B) / (A): ([number of moles of carbon-carbon double bond contained in component (B)] / [number of moles of thiol group contained in component (A)] (molar ratio)) , (C) / (A): ([number of moles of isocyanate group contained in component (C)] / [number of moles of thiol group contained in component (A)] (molar ratio)), ((B) + (C)) / (A): (([number of moles of carbon-carbon double bond contained in component (B)] + [number of moles of isocyanate group contained in component (C)]) / [(A) The number of moles of thiol groups contained in the component] (molar ratio)).

(Evaluation of transparent sheet)
Examples 1 to 5 (production of transparent sheet)
The heat-ultraviolet two-stage curable composition (D-1) obtained in Formulation Example 1 is coated on a Teflon sheet so that the film thickness after curing is 250 μm, and the solvent is 15 minutes at 80 ° C. for 5 minutes and 110 ° C. A semi-cured product (E-1) was obtained by drying and heat curing. The obtained semi-cured product (E-1) was peeled off from the Teflon sheet, fixed on the steel plate, and detected at 254 nm using an ultraviolet irradiation device (product name “UV-152” manufactured by USHIO INC.). The transparent sheet (F-1) was obtained by irradiating with ultraviolet rays so that the integrated light quantity became 500 mJ / cm ² with a container. Further, in order to evaluate the moldability, the obtained semi-cured product (E-1) was peeled off from the Teflon sheet and then fixed on the steel plate, and the semi-cured product was heated to 120 ° C. for 30 seconds. The circular pattern was transferred to a semi-cured product by pressing. After removing the mold, a transparent sheet (F-1 ′) was obtained by irradiating with an ultraviolet ray using an ultraviolet ray irradiator so that the integrated light amount was 500 mJ / cm ² with a 254 nm detector.
Similarly, using the heat-ultraviolet two-stage curable composition (D-2 to 5) obtained in Formulation Examples 2 to 5, according to Table 3, the transparent sheet (F-2 to 5) and the transparent sheet (F-2) '~ 5').

(Evaluation of transparent sheet)
Example 6 (Preparation of transparent sheet)
The heat-ultraviolet two-stage curable composition (D-6) obtained in Formulation Example 1 was coated on a Teflon sheet so that the film thickness after curing was 250 μm, and integrated with a 254 nm detector using an ultraviolet irradiation device. A semi-cured product (E-6) was obtained by irradiating ultraviolet rays so that the amount of light was 250 mJ / cm ² . The obtained semi-cured product (E-1) was peeled off from the Teflon sheet, then fixed on the steel plate, and heat-cured at 120 ° C. for 15 minutes to obtain a transparent sheet (F-6). In addition, in order to evaluate the moldability, the obtained semi-cured product (E-6) was peeled off from the Teflon sheet and then fixed on the steel plate, and then the semi-cured product was heated to 120 ° C. for 30 seconds. The circular pattern was transferred to a semi-cured product by pressing. After removing the mold, a transparent sheet (F-6 ′) was obtained by thermosetting at 120 ° C. for 15 minutes.

Comparative Example 1 (Preparation of transparent sheet)
The heat-ultraviolet curable composition (d-1) obtained in Formulation Example 6 was coated on a Teflon sheet so that the film thickness after curing was 250 μm, and the solvent was dried at 80 ° C. for 5 minutes and at 110 ° C. for 12 minutes. It was set as the semi-hardened material (e-1) by performing thermosetting. The obtained semi-cured product (e-1) is peeled off from the Teflon sheet, fixed on the steel plate, and irradiated with ultraviolet rays so that the integrated light quantity becomes 500 mJ / cm ² with a 254 nm detector using an ultraviolet irradiation device. Thus, a transparent sheet (f-1) was obtained. Further, in order to evaluate the moldability, the obtained semi-cured product (e-1) was peeled off from the Teflon sheet and then fixed on the steel plate, and then the semi-cured product was heated to 120 ° C. for 30 seconds. The circular pattern was transferred to a semi-cured product by pressing. After removing the mold, a transparent sheet (f-1 ′) was obtained by irradiating with an ultraviolet ray using an ultraviolet ray irradiator so that the integrated light amount became 500 mJ / cm ² with a 254 nm detector.

Comparative Example 2 (Preparation of transparent sheet)
The UV curable composition (d-2) obtained in Formulation Example 7 was coated on a Teflon sheet so that the film thickness after curing was 250 μm, and the integrated light quantity was 500 mJ / with a 254 nm detector using an ultraviolet irradiation device. The transparent sheet (f-2) was obtained by irradiating with ultraviolet rays so as to be cm ² . Since the liquid after the solvent drying step was liquid, a circular mold heated to 120 ° C. was pressed against the transparent sheet (f-2) for 30 seconds to transfer the circular pattern, but the pattern could not be transferred. . In addition, a circular mold heated to 120 ° C. was pressed against the transparent sheet (f-2) for 30 seconds to try to transfer the circular pattern. However, since the curing of the transparent sheet was completed, the circular pattern was transferred. I couldn't.

Comparative Example 3 (Preparation of transparent sheet)
The thermosetting composition (d-3) obtained in Formulation Example 8 was coated on a Teflon sheet so as to have a film thickness of 250 μm after curing, followed by solvent drying and thermosetting at 80 ° C. for 5 minutes and 110 ° C. for 12 minutes. Was performed to obtain a transparent sheet (f-3). A circular mold heated to 120 ° C. was pressed against the transparent sheet (f-3) for 30 seconds to try to transfer the circular pattern. However, since the transparent sheet was completely cured, the circular pattern could not be transferred. There wasn't. Further, the thermosetting composition (d-3) is coated on a Teflon sheet so that the film thickness after curing is 250 μm, and solvent-dried and heat-cured at 80 ° C. for 5 minutes and at 110 ° C. for 1 minute, and semi-cured (E-3). When a circular mold heated to 120 ° C. was pressed for 30 seconds to try to transfer the circular pattern, the mold and the semi-cured product were in close contact with each other, and the semi-cured material was broken when the mold was removed.

  The molding processability and transparency of the transparent sheets obtained in Examples 1 to 6 and Comparative Examples 1 to 3 were evaluated based on the following criteria.

(Molding processability)
○ ・ ・ ・ Shape transfer with mold is possible × ・ ・ ・ Shape transfer with mold is impossible

(transparency)
○ ・ ・ ・ Almost transparent △ ・ ・ ・ Translucent × ・ ・ ・ Opaque

  As a result, it was clarified that the transparent sheets of Examples 1 to 6 and Comparative Example 1 prepared by curing were excellent in moldability in a semi-cured state.

(Heat-resistant)
The transparent sheet obtained in Example 1 and Comparative Example 1 was cut into 5 mm × 30 mm, and viscoelasticity measuring instrument (manufactured by Seiko Instruments Inc., trade name “DMS6100”, measurement conditions: frequency 10 Hz, slope 3 ° C. / Min) was used to measure the dynamic storage modulus to evaluate the heat resistance. The measurement results are shown in FIG. As is clear from FIG. 1, it is recognized that Example 1 has a higher Tg than Comparative Example 1, has a small decrease in elastic modulus even at high temperatures, and is excellent in heat resistance.

(Evaluation of transparent sheet using support)
Example 7 (Production of shape-processed transparent sheet)
The thermo-ultraviolet curable composition (D-1) obtained in Formulation Example 1 is coated on a 100 μm thick PET film so that the film thickness after curing is 50 μm, and is 80 ° C. for 5 minutes and 110 ° C. for 12 minutes. By carrying out solvent drying and heat curing, a semi-cured transparent sheet (E-7) was obtained. A circular mold heated to 120 ° C. was pressed against the surface of the obtained transparent sheet with semi-cured product (E-7) on which the semi-cured product was attached, to transfer the circular pattern to the semi-cured product. After removing the mold, a transparent sheet (F-7) having a shape processed was obtained by irradiating ultraviolet rays with a 254 nm detector so that the integrated light amount was 500 mJ / cm ² using an ultraviolet irradiation device.

Comparative Example 4 (Production of shape-processed transparent sheet)
The thermo-ultraviolet curable composition (d-1) obtained in Formulation Example 6 was coated on a 100 μm thick PET film so that the film thickness after curing was 50 μm, and it was 5 minutes at 80 ° C. and 12 minutes at 110 ° C. By carrying out solvent drying and heat curing, a semi-cured transparent sheet (e-4) was obtained. A circular mold heated to 120 ° C. was pressed against the surface of the obtained transparent sheet with semi-cured product (e-4) with the semi-cured product to transfer the circular pattern to the semi-cured product. After removing the mold, a transparent sheet (f-4) having been processed into a shape was obtained by irradiating ultraviolet rays with a 254 nm detector so that the integrated light amount became 500 mJ / cm ² using an ultraviolet irradiation device.

Comparative Example 5 (Production of shape-processed transparent sheet)
The ultraviolet curable composition (d-2) obtained in Formulation Example 7 was coated on a 100 μm thick PET film so that the film thickness after curing was 50 μm, and the solvent was dried at 80 ° C. for 5 minutes. Then, the transparent sheet | seat (f-5) was obtained by irradiating an ultraviolet-ray so that integrated light quantity may be set to 500 mJ / cm < ² > with a 254 nm detector using an ultraviolet irradiation device. The pattern could not be transferred because it was liquid after the solvent drying step. In addition, a circular mold heated to 120 ° C. was pressed against the transparent sheet (f-5) for 30 seconds to try to transfer the circular pattern, but the pattern could not be transferred because the curing was completed. It was.

Comparative Example 6 (Preparation of transparent sheet)
The thermosetting composition (d-3) obtained in Formulation Example 8 was coated on a 100 μm thick PET film so that the film thickness after curing was 50 μm, and the solvent was dried at 80 ° C. for 5 minutes and at 110 ° C. for 12 minutes. And the transparent sheet (f-6) was obtained by performing thermosetting. A circular mold heated to 120 ° C. was pressed against the transparent sheet (f-6) for 30 seconds to try to transfer the circular pattern, but the pattern could not be transferred. Further, the thermosetting composition (d-3) is coated on a PET film having a thickness of 100 μm so that the film thickness after curing is 50 μm, dried at 80 ° C. for 5 minutes, and dried at 110 ° C. for 1 minute and thermally cured, A semi-cured transparent sheet (e-6) was obtained. When a circular mold heated to 120 ° C. was pressed for 30 seconds to try to transfer the circular pattern, the mold and the semi-cured product were in close contact with each other, and the semi-cured material was broken when the mold was removed.

Evaluation was performed in the same manner as the above-described criteria for the molding processability and transparency of the transparent sheets obtained in Example 7 and Comparative Examples 4 to 6.

  As a result, it became clear that the transparent sheets of Example 7 and Comparative Example 1 produced by curing were excellent in the moldability in a semi-cured state.

Formulation Example 10 (Production of UV-curable composition)
With respect to 70.4 parts of the formulation (D-8) obtained in Formulation Example 8, 29.6 parts of DMG was disposed as a diluent solvent to obtain an ultraviolet curable composition (d-4).

Example 8 (Preparation of transparent sheet by glass cloth impregnation)
The heat-ultraviolet curable composition (D-1) obtained in Formulation Example 1 was impregnated into a 90 μm-thick glass cloth (manufactured by Nitto Boseki Co., Ltd .: refractive index 1.558), 5 minutes at 80 ° C., 110 Solvent drying and thermosetting were carried out at 12 ° C. for 12 minutes to produce a transparent sheet. Furthermore, 20 μm of the heat-ultraviolet curable composition (D-1) was coated on both surfaces of the sheet, and the solvent was dried and heat-cured at 80 ° C. for 5 minutes and at 110 ° C. for 12 minutes. It was. The obtained semi-cured product (E-8) was wound around a paper tube having a diameter of 15 cm and stored in a dark place at room temperature for 24 hours. Subsequently, after press molding at 120 ° C. for 30 seconds, a UV-irradiation device is used to irradiate the UV light with a detector of 254 nm so that the integrated light quantity becomes 2000 mJ / cm ² , thereby forming a transparent sheet (F -8) was obtained.

Comparative Example 7 (Production of transparent sheet by glass cloth impregnation)
The ultraviolet curable composition (d-4) obtained in Formulation Example 10 was impregnated into a 90 μm-thick glass cloth (manufactured by Nitto Boseki Co., Ltd .: refractive index 1.558), and the solvent was dried at 80 ° C. for 5 minutes. It was made into a sheet. Furthermore, 20 μm of the ultraviolet curable composition (d-4) was coated on both surfaces of the sheet, and the solvent was dried at 80 ° C. for 5 minutes to form a sheet. The sheet was tacky and could not be wound. The obtained sheet was press-molded at 120 ° C. for 30 seconds, and then irradiated with ultraviolet rays so that the integrated light amount became 2000 mJ / cm ² with a 254 nm detector using an ultraviolet irradiation device, thereby having a film thickness of 105 μm. A sheet (f-7) was obtained.

Comparative Example 8 (Preparation of transparent sheet by glass cloth impregnation)
The thermosetting composition (d-3) obtained in Formulation Example 9 was impregnated into a 90 μm-thick glass cloth (manufactured by Nitto Boseki Co., Ltd .: refractive index 1.558), and solvent drying was performed at 80 ° C. for 5 minutes. It was made into a sheet. Furthermore, 20 μm of the thermosetting composition (d-3) was coated on both surfaces of the sheet, and the solvent was dried at 80 ° C. for 5 minutes to form a sheet. The sheet was tacky and could not be wound. The obtained sheet was press-molded at 120 ° C. for 30 seconds and then thermally cured at 120 ° C. for 15 minutes to obtain a transparent sheet (f-8) having a thickness of 105 μm.

Comparative Example 9 (Production of transparent sheet by glass cloth impregnation)
The thermosetting composition (d-3) obtained in Formulation Example 9 was impregnated into a 90 μm-thick glass cloth (manufactured by Nitto Boseki Co., Ltd .: refractive index 1.558), and solvent drying was performed at 80 ° C. for 5 minutes. It was made into a sheet. Furthermore, 20 μm of the thermosetting composition (d-3) was coated on both sides of the sheet, solvent-dried at 80 ° C. for 5 minutes, and heat-cured at 110 ° C. for 2 minutes to obtain a semi-cured product (e-8). The obtained semi-cured product (e-8) was wound around a paper tube having a diameter of 15 cm and stored in a dark place at room temperature for 24 hours. When it was taken out for pressing after 24 hours, curing had progressed and molding could not be performed.

  As a result of measuring the total light transmittance and haze of the transparent sheets obtained in Example 8 and Comparative Examples 7 to 9, Table 5 shows the storability in a semi-cured state. The evaluation criteria are as follows.

(Storage property in semi-cured state)
○: The semi-cured state is maintained for 24 hours or more.
Δ: A semi-cured state is maintained for 24 hours or more, but cannot be wound and stored because of tackiness.
X: The semi-cured state is lost by 24 hours and cannot be molded.

  As a result, since the transparent sheet obtained in Example 8 was flattened and there was no light scattering due to fine irregularities on the surface, the haze was lower than that of the transparent sheets obtained in Comparative Examples 7-9. . Moreover, the storage property of the transparent sheet obtained in Example 8 was good as compared with Comparative Examples 7-9.

Fig. 1: Measurement results of dynamic storage elastic modulus of the transparent sheets obtained in Example 1 and Comparative Example 1

Claims (5)

General formula (1):
R ¹ Si (OR ² ) ₃ (1)
(In the formula, R ¹ represents a hydrocarbon group having 1 to 8 carbon atoms having at least one thiol group or an aromatic hydrocarbon group having at least one thiol group, and R ² represents a hydrogen atom or 1 carbon atom) A condensate (A) obtained by hydrolysis and condensation of a thiol group-containing alkoxysilane (a1) represented by -8 hydrocarbon groups or aromatic hydrocarbon groups, and two allyl groups. The compound (B) contained above and the compound (C) having an isocyanate group [{number of double bonds contained in component (B)} / {number of thiol groups in component (A)}] 0.1 to 0.8, [{number of isocyanate groups contained in component (C)} / (number of thiol groups in component (A)}) is 0.1 to 0.8, [{(B ) Number of carbon-carbon double bonds contained in component + (C) Isocyanate in component The resin composition (D) containing 0.9 to 1.1 in the ratio of the number of radical groups} / {number of thiol groups in component (A)}] is obtained by two-stage curing with heat and ultraviolet rays. Transparent sheet. 2. The transparent sheet according to claim 1, wherein the two-stage curing is a method in which the resin composition (D) is thermally cured to be in a semi-cured state, is molded and then cured with ultraviolet rays. 2. The transparent sheet according to claim 1, wherein the two-stage curing is a method in which the resin composition (D) is UV-cured to be in a semi-cured state, molded and then thermally cured. The transparent sheet in any one of Claims 1-3 produced on the transparent support body. The transparent sheet according to any one of claims 1 to 3, which is obtained by impregnating a glass cloth with the resin composition (D), followed by two-stage curing with heat and ultraviolet rays.