Thermosetting silicone resin composition and laminate

Abstract

The present invention provides: a thermosetting silicone resin composition which has excellent adhesion to a cyclic olefin resin base material and is capable of imparting excellent pencil hardness; and a laminate which uses the thermosetting silicone resin composition.　The present invention specifically provides a thermosetting silicone resin composition which is used as a cured coating layer of a cyclic olefin resin base material, and which is characterized by containing: a reactive silicone resin (A) which contains, as a main component, a polyorganosilsesquioxane that is represented by general formula (1) [RSiO3 / 2]n (wherein R is an organic functional group that has a (meth)acryloyl group, and n is 8, 10 or 12) and has a cage structure in a structural unit; a polyfunctional (meth)acrylate monomer (B) that contains at least three (meth)acryloyl groups in each molecule; and an organic peroxide (C). The thermosetting silicone resin composition is also characterized in that: 24-80 parts by weight of the component (A), 19-75 parts by weight of the component (B), and 0.5-10 parts by weight of the component (C) are contained relative to a total of 100 parts by weight of the components (A), (B), and (C); and the total number of (meth)acrylic moles of the polyfunctional (meth)acrylate monomer (B) that contains at least three (meth)acryloyl groups in each molecule contained in 100 g of the composition is 0.20-0.75.

Description

Thermosetting silicone resin composition and laminate

[0001] The present invention relates to a thermosetting silicone resin composition that has excellent adhesion to cyclic olefin resin substrates and can impart excellent pencil hardness, and to a laminate using the same.

[0002] In recent years, there has been a growing need for design, weight reduction, and thinning in all fields, including displays, mobile devices, home appliances, and automotive parts. Plastics and lightweight metals are being used as surface protection materials, replacing the glass and metals used until now. However, plastics and some lightweight metals have the problem of low surface hardness and susceptibility to scratches. Therefore, a method of providing a hard coating layer (also called a hardened coating layer) to protect the surface has been used.

[0003] Acrylic compositions are often used for such hard coat layers. Acrylic compositions generally form films and cure through radical reactions caused by irradiation with active energy rays such as ultraviolet rays or electron beams, allowing them to cure in a short time and at low temperatures, and because they can maintain toughness depending on the resin composition they contain, they are widely used in paints, adhesives, and the like.

[0004] As an example of such a hard coat layer, the present inventors have focused on reactive silicone resins having a cage structure and reactive functional groups, and have found that by increasing the number of reactive functional groups in this reactive silicone resin having a cage structure and blending it with an unsaturated compound capable of radical copolymerization in a specific ratio, it is possible to obtain a transparent silicone resin molded product that is excellent in balance between high surface hardness, heat resistance, mechanical properties, dimensional stability, etc., and has disclosed that this can be suitably used as a substitute for inorganic glass (Patent Documents 1 and 2).

[0005] On the other hand, cyclic olefin resins are increasingly being used as optical components for mobile phones, smartphones, liquid crystal displays, and the like due to their high transparency, low moisture absorption, and other functionalities. Cyclic olefin resins are easily scratched due to their relatively low surface hardness. Therefore, a hard coat layer is provided on the surface. However, the adhesion between the cyclic olefin resin and the cured coating layer is not always sufficient. Therefore, prior to forming the cured coating layer, an adhesion-enhancing treatment step, such as corona discharge treatment, plasma treatment, or ozone treatment of the cyclic olefin resin surface, or coating with an adhesion-enhancing primer composition, was required (Patent Document 3).

[0006] Patent Documents 4 and 5 propose a method of using an active energy ray-curable composition containing a diphenyl sulfide-based compound, a benzophenone-based compound, and a compound having a (meth)acryloyl group, as a cured coating layer on a cyclic olefin resin substrate that does not require the above-mentioned adhesion-enhancing treatment, and a method of using an active energy ray-curable composition containing a polyfunctional (meth)acrylate, a benzophenone-based compound, and a polysiloxane.

[0007] However, when attempting to form a cured coating layer on a cyclic olefin resin substrate having a complex shape such as a lens, it is difficult to uniformly irradiate the active energy rays with an active energy ray-curable composition, which results in variations in the hardness and adhesion of the cured coating layer, making it difficult to fully exhibit its performance.

[0008] Japanese Patent No. 4558643 Japanese Patent No. 5698566 JP 2008-518280 A JP 2015-127102 A JP 2016-105164 A

[0009] The present invention relates to a thermosetting silicone resin composition that has excellent adhesion to cyclic olefin resin substrates and can impart excellent pencil hardness, and to a laminate using the same.

[0010] The present inventors discovered that the above-mentioned problems can be solved with respect to such a thermosetting silicone resin composition, particularly by including a polymerizable compound having a specific structure as the radically polymerizable unsaturated compound in the composition in a specific ratio, and by combining the composition with a specific thermal polymerization initiator, and thus arrived at the present invention.

[0011] That is, the present invention is as follows: (1) A thermosetting silicone resin composition used as a cured coating layer on a cyclic olefin resin substrate, the composition comprising a silicone resin having a general formula (1): [RSiO ３ / ２ ] ｎ (1) A thermosetting silicone resin composition comprising: a reactive silicone resin (A) represented by the formula (wherein R is an organic functional group having a (meth)acryloyl group, and n is 8, 10, or 12), the reactive silicone resin (A) containing, as a main component, a polyorganosilsesquioxane having a cage structure in its structural unit; a polyfunctional (meth)acrylate monomer (B) containing at least three (meth)acryloyl groups in its molecule; and an organic peroxide (C); wherein, relative to 100 parts by weight of the total of components (A), (B), and (C), the composition contains 24 to 80 parts by weight of component (A), 19 to 75 parts by weight of component (B), and 0.5 to 10 parts by weight of component (C); and wherein the total number of (meth)acrylic moles of the polyfunctional (meth)acrylate monomer (B) containing at least three (meth)acryloyl groups in its molecule, contained in 100 g of the composition, is 0.20 to 0.75.

[0012] (2) The thermosetting silicone resin composition according to (1), wherein the organic peroxide (C) generates tert-butoxy radicals upon heating.

[0013] (3) The thermosetting silicone resin composition according to (1), further comprising an inorganic filler (D) having a primary particle size of 1 to 100 nm in an amount of 1 to 50 parts by weight per 100 parts by weight of the total of components (A) and (B).

[0014] (4) A laminate having a cured coating layer formed on a cyclic olefin resin substrate using the heat-curable silicone resin composition according to any one of (1) to (3).

[0015] (5) The laminate according to (4), wherein the cyclic olefin resin substrate is not subjected to an easy-adhesion treatment.

[0016] The present invention can provide a thermosetting silicone resin composition that has excellent adhesion to cyclic olefin resin substrates and can impart excellent pencil hardness, and a laminate using the same.

[0017] Each element constituting the present invention will be described in detail below, but the following description is an example of an embodiment of the present invention, and the present invention is not limited to the following description as long as it does not deviate from the gist of the present invention. In this specification, when the expression "to" is used, it is used as an expression including the numerical values ​​or physical property values ​​before and after it. Furthermore, in the present invention, when the expression "(meth)acrylic" is used, it means one or both of "acrylic" and "methacrylic". The same applies to "(meth)acrylate" and "(meth)acryloyl".

[0018] The heat-curable silicone resin composition of the present invention comprises a silicone compound represented by the general formula (1) [RSiO ３ / ２ ] ｎ (1) [wherein R is an organic functional group having a (meth)acryloyl group, and n is 8, 10, or 12], and characterized in that it contains a reactive silicone resin (A) containing, as a main component, a polyorganosilsesquioxane having a cage structure in its structural unit, a polyfunctional (meth)acrylate monomer (B) containing at least three (meth)acryloyl groups in the molecule, and an organic peroxide (C). Hereinafter, these may be referred to as component (A), component (B), and component (C), respectively.

[0019] The reactive silicone resin (A) is represented by the following general formula (1) and is composed primarily of a polyorganosilsesquioxane (also called a cage-type polyorganosilsesquioxane; polyorganosilsesquioxane is also called silsesquioxane) having a cage structure in its structural unit. The polyorganosilsesquioxane is preferably contained in component (A) in an amount of 50% by weight or more, more preferably 75% by weight or more, and even more preferably 90% by weight or more. [RSiO ３／２ ] ｎ (1)

[0020] In the above general formula (1), R is an organic functional group having a (meth)acryloyl group, and n is 8, 10, or 12. Examples of R include groups represented by the following general formula (2): CH ２ =CR １ -COO-(CH ２ ) ｍ - (2) In formula (2), m is an integer of 1 to 3, and R １ is a hydrogen atom or a methyl group.

[0021] Such reactive silicone resin (A) has an organic functional group having a (meth)acryloyl group on a silicon atom in the molecule. Specific structures of cage-type polyorganosilsesquioxanes in which n in general formula (1) is 8, 10, or 12 include cage structures shown in the following structural formulas (1), (2), and (3), respectively. Note that R in the following formulas represents the same as R in general formula (1).

[0022]

[0023] Here, such reactive silicone resin (A) can be produced by the methods described in Patent Documents 1 and 2. For example, a silicone resin (A) having the general formula "RSiX ３ " in the presence of a polar solvent and a basic catalyst, is subjected to hydrolysis and partial condensation, and the resulting hydrolysis product is further re-condensed in the presence of a non-polar solvent and a basic catalyst. ３In the formula (I), R is an organic functional group having a (meth)acryloyl group, and is the same as R in the reactive silicone resin (A) represented by general formula (1), for example, a group represented by general formula (2). Specific preferred examples of R include a 3-methacryloxypropyl group, a methacryloxymethyl group, and a 3-acryloxypropyl group. X represents a hydrolyzable group.

[0024] The general formula "RSiX" used as a raw material ３ In the silicon compound represented by the formula (I), the hydrolyzable group X is not particularly limited as long as it is a group having hydrolyzability, and examples thereof include an alkoxyl group and an acetoxy group, with an alkoxyl group being preferred. Examples of the alkoxyl group include a methoxy group, an ethoxy group, an n- or i-propoxy group, or an n-, iso- or tert-butoxy group. A methoxy group is preferred due to its high reactivity.

[0025] RSiX ３ Among the silicon compounds represented by the formula (I), preferred compounds include methacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane, 3-methacryloxypropyltrichlorosilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-acryloxypropyltrichlorosilane. Of these, it is preferred to use 3-methacryloxypropyltrimethoxysilane, which is a readily available raw material.

[0026] Examples of basic catalysts used in the hydrolysis reaction include alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, and cesium hydroxide, and ammonium hydroxide salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, and benzyltriethylammonium hydroxide. Among these, tetramethylammonium hydroxide is preferred because of its high catalytic activity. The basic catalyst is usually used as an aqueous solution.

[0027] Regarding hydrolysis reaction conditions, the reaction temperature is preferably 0 to 60°C, more preferably 20 to 40°C. If the reaction temperature is lower than 0°C, the reaction rate will be slow and the hydrolyzable groups will remain unreacted, resulting in a long reaction time. On the other hand, if the temperature is higher than 60°C, the reaction rate will be too fast, leading to the progress of complex condensation reactions, which will result in the promotion of high molecular weight hydrolysis products. In addition, the reaction time is preferably 2 hours or more. If the reaction time is less than 2 hours, the hydrolysis reaction may not proceed sufficiently, resulting in the risk of the hydrolyzable groups remaining unreacted.

[0028] The hydrolysis reaction requires the presence of water, which can be supplied from an aqueous solution of a basic catalyst or added separately. The amount of water should be at least an amount sufficient to hydrolyze the hydrolyzable groups, preferably 1.0 to 1.5 times the theoretical amount. Furthermore, an organic polar solvent must be used during the hydrolysis. Examples of the organic polar solvent include alcohols such as methanol, ethanol, and 2-propanol, as well as other organic polar solvents. Preferably, the solvent is a lower alcohol having 1 to 6 carbon atoms that is soluble in water, and 2-propanol is more preferred. The use of a nonpolar solvent is undesirable because the reaction system is not homogeneous, the hydrolysis reaction does not proceed sufficiently, and unreacted hydrolyzable groups remain.

[0029] After completion of the hydrolysis reaction, water or a water-containing reaction solvent is separated. The separation of water or a water-containing reaction solvent can be performed by evaporation under reduced pressure or other methods. To sufficiently remove moisture and other impurities, a nonpolar solvent can be added to dissolve the hydrolysis reaction product, and the solution can be washed with saline or the like, followed by drying with a desiccant such as anhydrous magnesium sulfate. The hydrolysis reaction product can be recovered by separating the nonpolar solvent by evaporation or other methods, but if the nonpolar solvent can be used as the nonpolar solvent for the subsequent reaction, there is no need to separate it.

[0030] During the hydrolysis reaction, a condensation reaction of the hydrolyzate occurs along with the hydrolysis. The hydrolysis product resulting from the condensation reaction of the hydrolyzate typically becomes a colorless viscous liquid with a number-average molecular weight of 1,400 to 5,000. The hydrolysis product, depending on the reaction conditions, becomes an oligomer with a number-average molecular weight of 1,400 to 3,000, in which most, preferably almost all, of the hydrolyzable groups X are substituted with OH groups, and most, preferably 95% or more, of the OH groups are condensed. The structures of the hydrolysis products include multiple types of cage-type, ladder-type, and random-type silsesquioxanes. Even among compounds with a cage structure, the proportion of complete cage structures is low, with incomplete cage structures in which the cage is partially open being the majority. Therefore, the hydrolysis product obtained by this hydrolysis is further heated in an organic solvent in the presence of a basic catalyst to condense the siloxane bonds (recondensation), thereby selectively producing cage-type silsesquioxanes.

[0031] Specifically, the reaction is carried out as follows. After the hydrolysis reaction is completed as described above, water or the water-containing reaction solvent is separated, and then the recondensation reaction is carried out in the presence of a nonpolar solvent and a basic catalyst. Regarding the reaction conditions for the recondensation reaction, the reaction temperature is preferably in the range of 100 to 200°C, and more preferably 110 to 140°C. Furthermore, if the reaction temperature is too low, sufficient driving force for the recondensation reaction is not obtained, and the reaction does not proceed. If the reaction temperature is too high, the (meth)acryloyl group may undergo self-polymerization, so it is necessary to suppress the reaction temperature or add a polymerization inhibitor or the like. The reaction time is preferably 2 to 12 hours. The amount of nonpolar solvent used should be sufficient to dissolve the hydrolysis reaction product, and the amount of basic catalyst used should be in the range of 0.1 to 10 parts by mass (wt%) relative to the hydrolysis reaction product.

[0032] The nonpolar solvent may be one that is insoluble or almost insoluble in water, but hydrocarbon solvents are preferred. Examples of such hydrocarbon solvents include nonpolar solvents with low boiling points such as toluene, benzene, and xylene. Toluene is particularly preferred. The basic catalyst may be any of the basic catalysts used in the hydrolysis reaction, including alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, and cesium hydroxide, and ammonium hydroxide salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, and benzyltriethylammonium hydroxide. However, catalysts soluble in nonpolar solvents, such as tetraalkylammonium hydroxide, are preferred.

[0033] Furthermore, the hydrolysis product used in the recondensation is preferably washed with water, dehydrated, and concentrated, but can be used without washing or dehydration. During this reaction, water may be present, but it is not necessary to actively add it; it is preferable to limit the amount of water to that carried over from the basic catalyst solution. If the hydrolysis product is not sufficiently hydrolyzed, more water than the theoretical amount required to hydrolyze the remaining hydrolyzable groups is required, but the hydrolysis reaction is usually carried out sufficiently. After the recondensation reaction, the catalyst is washed away with water, and the mixture is concentrated to obtain a silsesquioxane mixture. The resulting silsesquioxane mixture preferably has the same number of silicon atoms and (meth)acryloyl groups in the molecule.

[0034] The silsesquioxane mixture obtained in this manner will vary depending on the reaction conditions and the state of the hydrolysis product, but its constituent components are thought to be 70% or more of the total multi-cage silsesquioxane, with the remainder being ladder-type and random-bridged silsesquioxanes. Because separation of these components is difficult and requires a great deal of effort, in the present invention, when using a cage-type silsesquioxane represented by general formula (1), it is preferable to use a silsesquioxane containing 70% or more of multi-cage silsesquioxanes. Note that there is no difference in the effects obtained as long as the cage-type silsesquioxane content is 70% or more. The constituent components of the multi-cage silsesquioxane are 20 to 40% T8 represented by structural formula (1), 40 to 50% T10 represented by structural formula (2), and the remaining component is T12 represented by structural formula (3). T8 can be separated by precipitating it as needle-shaped crystals by leaving the silsesquioxane mixture at 20°C or below. The content of the cage-type silsesquioxane can be confirmed using, for example, GPC or LC-MS.

[0035] Such reactive silicone resins may be mixtures of T8 to T12, or may be those in which T8 or T2 has been separated or concentrated, but are not limited to silicone resins obtained by the above-mentioned production method.

[0036] The reactive silicone resin (A) is blended in an amount of 24 to 80 parts by weight per 100 parts by weight of the total of components (A), (B), and (C). It is preferably 25 to 80 parts by weight, more preferably 27 to 78 parts by weight, and even more preferably 29 to 75 parts by weight. If the amount is too small, the reactivity decreases, resulting in poor adhesion, and the crosslink density also decreases, which may result in softening and poor pencil hardness. If the amount is too large, the crosslink density increases, making the composition hard and brittle, which may result in cracking or peeling.

[0037] The polyfunctional (meth)acrylate monomer (B) is blended in an amount of 19 to 75 parts by weight, preferably 20 to 75 parts by weight, more preferably 22 to 72 parts by weight, and even more preferably 25 to 70 parts by weight, per 100 parts by weight of the total of components (A), (B), and (C).

[0038] Furthermore, the total number of (meth)acrylic moles of the polyfunctional (meth)acrylate monomer (B) contained in 100 g of the thermosetting silicone resin composition should be 0.20 to 0.75. This range is preferably 0.22 to 0.73, and more preferably 0.24 to 0.70. If the number of (meth)acrylic moles is too low, crosslinking may not be formed properly, potentially reducing adhesion to the cyclic olefin resin substrate. If the number of (meth)acrylic moles is too high, shrinkage stress during curing may increase, potentially reducing adhesion.

[0039] The polyfunctional (meth)acrylate monomer (B) is characterized by being a polyfunctional unsaturated compound containing at least three (meth)acryloyl groups in the molecule.

[0040] Examples of the polyfunctional (meth)acrylate monomer (B) include pentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetraacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate. In addition to these, compounds in which some or all of the hydroxy groups of pentaerythritol or dipentaerythritol have been modified with glycols such as ethylene or isopropylene, or γ-butyrolactone, and all of the terminal hydroxy groups of the resulting skeleton have been modified with unsaturated groups, can also be used. Other examples include urethane acrylate and acrylic copolymer acrylate. These compounds may be used alone or in combination of two or more.

[0041] The number of (meth)acrylic moles of the polyfunctional (meth)acrylate monomer (B) containing at least three (meth)acryloyl groups in the molecule, which is contained in 100 g of the above-mentioned heat-curable silicone resin composition, is the number of (meth)acrylic moles of the polyfunctional (meth)acrylate monomer (B) containing at least three (meth)acryloyl groups in the molecule per 100 g of the heat-curable silicone resin composition (number of (meth)acrylic functional groups / molecular weight g mol －１ )

[0042] The organic peroxide (C) is blended in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the total of components (A), (B), and (C). The amount is preferably 0.5 to 8 parts by weight, and more preferably 1 to 6 parts by weight. If the amount is too small, crosslinking may be insufficient, resulting in reduced adhesion and a reduced modulus of elasticity, and the desired pencil hardness may not be obtained. If the amount is too large, the number of (meth)acrylic moles in the thermosetting silicone resin composition may decrease, resulting in insufficient crosslinking, reduced adhesion, and a reduced modulus of elasticity, and the desired pencil hardness may not be obtained.

[0043] Examples of the organic peroxide (C) include peroxyketals such as 1,1-bis(tert-hexylperoxy)cyclohexane, 1,1-di(tert-butylperoxy)cyclohexane, and 4,4-bis[(tert-butyl)peroxy]butyl pentanoate, ketone peroxides such as ethyl methyl ketone peroxide and 2,4-pentanedione peroxide, hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, [2-(4-methylcyclohexyl)propan-2-yl]hydroperoxide and 1,1,3,3-tetramethylbutyl hydroperoxide, 1,4-bis[(tert-butylperoxy)isopropyl]benzene, tert-butyl-α-cumyl peroxide, and 2,5-dimethyl Examples of organic peroxides include, but are not limited to, dialkyl peroxides such as 2,5-bis(tert-butylperoxy)hexane, 2,5-bis(tert-butylperoxy)-2,5-dimethyl-3-hexyne, and bis(1-phenyl-1-methylethyl)peroxide; peroxy esters such as tert-butylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2-methylpentan-2-yl benzoperoxoate, and 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate; and peroxydicarbonates such as bis(isopropoxycarbonyl)peroxide, peroxybis(2-ethylhexylformate), and bis(1-methylpropyloxycarbonyl)peroxide. These organic peroxides may be used alone or in combination of two or more.

[0044] Among these, the radical generated by heating is preferably a tert-butoxy radical, which has a strong intermolecular hydrogen abstraction effect. That is, the organic peroxide (C) is preferably one that generates a tert-butoxy radical by heating. By using an organic peroxide that generates this radical, denser crosslinks can be formed, improving adhesion and pencil hardness.

[0045] Examples of the organic peroxide (C) that generates a tert-butoxy radical include, but are not limited to, 1,1-bis(tert-hexylperoxy)cyclohexane, 1,1-di(tert-butylperoxy)cyclohexane, 4,4-bis[(tert-butyl)peroxy]butyl pentanoate, 1,4-bis[(tert-butylperoxy)isopropyl]benzene, tert-butyl-α-cumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-bis(tert-butylperoxy)-2,5-dimethyl-3-hexyne, and tert-butylperoxy-2-ethylhexanoate. Among the organic peroxides (C) that generate a tert-butoxy radical, 1,1-di(t-butylperoxy)cyclohexane is more preferably used because of its large theoretical active oxygen content and low reaction initiation temperature.

[0046] The thermosetting silicone resin composition of the present invention can be blended with an inorganic filler (D). The inorganic filler (D) is not particularly limited, but preferred examples include the following inorganic oxide fine particles and inorganic halide fine particles. Blending with the inorganic filler (D) can further increase the pencil hardness of the cured coating layer of the thermosetting silicone resin composition and of a laminate having a cured coating layer.

[0047] Examples of the inorganic filler (D) include oxides of silicon, aluminum, zirconium, titanium, zinc, lead, germanium, indium, tin, antimony, cerium, lithium, and the like, or composite oxides thereof, specifically, silicon oxide (silica), aluminum oxide (alumina), silicon-aluminum composite oxide, zirconium oxide (zirconia), titanium oxide (titania), zinc oxide, tin oxide, phosphorus-doped tin oxide (PTO), antimony-doped tin oxide, indium-tin composite oxide (ITO), cerium oxide, silica-lithium composite oxide, etc. Furthermore, examples of inorganic halide fine particles include alkali metal halides such as lithium chloride, sodium fluoride, potassium bromide, etc.; alkaline earth metal halides such as calcium fluoride, magnesium chloride, etc.

[0048] The average primary particle size of the inorganic filler (D) is preferably 1 to 100 nm. In particular, from the viewpoint of improving the pencil hardness of the cured coating layer, it is advantageous to use one with a relatively large average primary particle size, but from the viewpoint of achieving both pencil hardness and transparency, a range of 5 nm to 100 nm is more preferable. If the average primary particle size is less than 1 nm, the effect of improving the pencil hardness of the cured coating layer may be reduced when used in combination with other organic materials. If the average primary particle size exceeds 100 nm, the transparency of the thermosetting silicone resin composition may be impaired.

[0049] The inorganic filler (D) is preferably blended in an amount of 1 to 50 parts by weight, more preferably 3 to 30 parts by weight, and even more preferably 5 to 20 parts by weight, per 100 parts by weight of the thermosetting silicone resin composition. If the amount is too small, the effect of improving the pencil hardness of the cured coating layer will be small, and if the amount is too large, the flatness of the cured coating layer may be impaired.

[0050] The method for obtaining the cured coating layer may be either in an oxygen-blocking atmosphere or in the air. However, since the composition of the present invention provides a good cured coating layer even when polymerized and cured in the air, it is preferably performed in the air. For example, a cured coating layer can be formed by coating the thermosetting silicone resin composition of the present invention on a cyclic olefin resin substrate, or by diluting it with various organic solvents and coating it, followed by a drying process and curing with heat. Examples of coating methods include the flow coating method, roller coating method, bar coating method, spray coating method, inkjet method, air knife coating method, spin coating method, flow coating method, curtain coating method, and dipping method. The coating film thickness is adjusted by the solids concentration, taking into account the film thickness formed after drying and thermal curing. If an organic solvent is used to adjust the solids concentration, it is preferable to remove the organic solvent by drying or the like after coating. The drying temperature is set to a temperature that does not deform the substrate used, and the drying time is preferably 1 hour or less from the perspective of productivity. Furthermore, the thermal curing temperature is not limited, but is preferably 100 to 125°C, more preferably 110 to 120°C. The thermal curing time is also not limited, but is preferably 1 to 10 hours, more preferably 2 to 6 hours. If the curing temperature is higher than 125°C, the cyclic olefin resin substrate may soften, while if it is lower than 100°C, crosslinking may not proceed sufficiently, resulting in a decrease in hardness and adhesion.

[0051] Specific examples of the organic solvent include known organic solvents, such as aromatic organic solvents such as toluene and xylene, ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester organic solvents such as ethyl acetate, n-propyl acetate, isopropyl acetate and isobutyl acetate, alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol and n-butanol, and glycol ether organic solvents such as propylene glycol monomethyl ether. In particular, it is preferable to use a glycol organic solvent.

[0052] Examples of glycol ether organic solvents include ethylene glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol n-propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol dipropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol dibutyl ether, ethylene glycol isoamyl ether, ethylene glycol monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, methoxyethoxyethanol, and ethylene glycol monoallyl ether; and propylene glycols such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and butoxypropanol, with propylene glycol monomethyl ether being preferred.

[0053] The thickness of the cured coating layer made from the thermosetting silicone resin composition is preferably in the range of 0.5 to 20 μm, more preferably 1 to 10 μm, and even more preferably 3 to 7 μm. If the amount is too small, the desired pencil hardness cannot be obtained, while if the amount is too large, the contraction stress of the cured coating layer during curing is so large that cracks may occur or adhesion may decrease.

[0054] From the viewpoint of shortening the process for producing the laminate, it is preferable that the cyclic olefin resin substrate is not subjected to an easy-adhesion treatment, but there is no problem if it is subjected to an easy-adhesion treatment. Examples of the easy-adhesion treatment include known easy-adhesion treatments such as corona discharge treatment, plasma treatment, ozone treatment, and coating with an easy-adhesion primer composition.

[0055] As the cyclic olefin resin substrate, any homopolymer or copolymer can be used without any particular limitation as long as it is a polymer of a cyclic olefin. Commercially available cyclic olefin resins include, for example, "ZEONOR" manufactured by Nippon Zeon Co., Ltd., "ARTON" manufactured by JSR Corporation, "TOPAS" manufactured by Polyplastics Co., Ltd., and "APL" manufactured by Mitsui Chemicals, Inc. The shape of the cyclic olefin resin substrate may be a molded body or a film, and the thickness is not particularly limited.

[0056] The thermosetting silicone resin composition used in the present invention may further contain various additives as needed, and may be diluted with a solvent if desired. Examples of additives that can be used include ultraviolet absorbers, light stabilizers, antioxidants, rheology control agents, surface conditioners (silicon-based surface conditioners, acrylic-based surface conditioners, fluorine-based surface conditioners, vinyl-based surface conditioners, etc.), surfactants, resin particles, lubricants, defoamers, mold release agents, silane coupling agents, antistatic agents, antifogging agents, and colorants.

[0057] The ultraviolet absorber may be any of the conventionally known organic and inorganic ultraviolet absorbers, such as benzotriazole-based absorbers, triazine-based absorbers, salicylic acid derivative-based absorbers, benzophenone-based absorbers, and other compounds (hydroxyphenyltriazines, oxalic acid anilide, cyanoacrylate, etc.). Examples of inorganic ultraviolet absorbers include fine particle titanium oxide, fine particle zinc oxide, and fine particle iron oxide. The ultraviolet absorber may also have a polymerizable unsaturated group. When the ultraviolet absorber is contained, the content of the ultraviolet absorber is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, per 100 parts by weight of all cured coating-forming components.

[0058] The light stabilizer is not particularly limited, and a wide variety of conventionally known light stabilizers can be used, but preferred examples include hindered piperidine compounds. The hindered piperidine compound is a compound having at least one hindered piperidine group in one molecule. Examples of the hindered piperidine compound include monomer-type compounds such as bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, and bis(1,2,2,6,6-pentamethyl-4-piperidyl){[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl}butylmalonate; Examples of the light stabilizer include, but are not limited to, oligomer types such as (1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl)[(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)iminol]}; and polyester bond types such as a polyesterification product of 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol and succinic acid. Also usable as the light stabilizer are known polymerizable light stabilizers.

[0059] Commercially available light stabilizers include, for example, TINUVIN 123, TINUVIN 152, TINUVIN 292, and TINUVIN 479 (trade names, manufactured by BASF), HOSTAVIN 3050, HOSTAVIN 3052, and HOSTAVIN 3058 (trade names, manufactured by Clariant), and Adekastab LA-82 (trade name, manufactured by ADEKA). These may be used alone or in combination of two or more. Furthermore, when the light stabilizer is contained, the content thereof is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, per 100 parts by weight of all curable coating-forming components.

[0060] The laminate of the present invention can be obtained by forming a cured coating layer made of a thermosetting silicone resin composition on a cyclic olefin substrate using the method described above. Furthermore, an inorganic substance layer can be further formed on the cured coating layer to impart mechanical, electrical, optical, or chemical functions. The inorganic substance layer is not particularly limited as long as it is formed by a dry film-forming method, and can be selected depending on the properties to be imparted to the laminate. Examples of the inorganic substance layer include layers mainly composed of at least one of various metals containing elements such as Si, Ti, Zn, Al, Ga, In, Ce, Bi, Sb, B, Zr, Sn, and Ta, or metal oxides, nitrides, sulfides, etc.

[0061] Among these, the inorganic material layer of the optical member is preferably a layer made of a metal oxide, particularly a silicon oxide compound, from the viewpoint of high hardness, low reflectance, and transparency. Examples of silicon oxide compounds include silicon monoxide, silicon dioxide, and silicon suboxide.

[0062] The method for laminating the inorganic substance layer is not particularly limited as long as it is a dry film formation method, and examples thereof include physical vapor deposition methods (hereinafter also referred to as "PVD") such as resistance heating evaporation, electron beam evaporation, molecular beam epitaxy, ion beam deposition, ion plating, ion-assisted evaporation, and sputtering, and chemical vapor deposition methods (hereinafter also referred to as "CVD") such as thermal CVD, plasma CVD, photo CVD, epitaxial CVD, atomic layer CVD, and cat CVD, but ion-assisted evaporation is preferred because it can produce a highly adhesive, high-density, and stable film. The dry film formation method referred to here is a method in which the surface of a material is treated using a gas phase or a molten state, and is sometimes generally called a dry process.

[0063] The thermosetting silicone resin composition used in the present invention can form a laminate that has excellent adhesion to cyclic olefin resin substrates and excellent pencil hardness, for example, a pencil hardness (according to JIS K 5600) of preferably F or higher, more preferably H or higher, and even more preferably 2H or higher.

[0064] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following.

[0065] Synthesis Example 1 A reaction vessel equipped with a stirrer, dropping funnel, and thermometer was charged with 40 ml of 2-propanol (IPA) as a solvent and 5% aqueous tetramethylammonium hydroxide (TMAH solution) as a basic catalyst. 15 ml of IPA and 12.69 g of 3-methacryloxypropyltrimethoxysilane (MTMS) (XIAMETER.OFS-6030 Silane, manufactured by Dow-Toray Industries, Inc.) were placed in the dropping funnel, and the MTMS IPA solution was added dropwise over 30 minutes at room temperature while stirring the reaction vessel. After the MTMS addition was complete, the mixture was stirred for 2 hours without heating. After stirring for 2 hours, the solvent was removed under reduced pressure and the mixture was dissolved in 50 ml of toluene. The reaction solution was washed with saturated saline until neutral and then dehydrated with anhydrous magnesium sulfate. The anhydrous magnesium sulfate was filtered off and the mixture was concentrated to obtain 25.8 g of a hydrolysis product (silsesquioxane). This silsesquioxane was a colorless viscous liquid soluble in various organic solvents. Next, 20.65 g of the silsesquioxane obtained above, 82 ml of toluene, and 3.0 g of a 10% aqueous TMAH solution were placed in a reaction vessel equipped with a stirrer, a Dinstark, and a condenser, and gradually heated to distill off water. The mixture was further heated to 130°C, and a recondensation reaction was carried out at the toluene reflux temperature. The temperature of the reaction solution at this time was 108°C. After 2 hours of stirring following the toluene reflux, the reaction was terminated. The reaction solution was washed with saturated saline until neutral and then dehydrated over anhydrous magnesium sulfate. The anhydrous magnesium sulfate was filtered off, and the mixture was concentrated to obtain 18.77 g of the target cage-type silsesquioxane (mixture). The resulting cage-type silsesquioxane (A-1) was a colorless viscous liquid soluble in various organic solvents. When the reaction product after the recondensation reaction was separated by liquid chromatography and then subjected to gravimetric analysis, molecular ions with ammonium ions were confirmed for the molecular structures of the above structural formulas (1), (2), and (3) in which R was a methacryloxypropyl group, and the composition ratio of T8:T10:T12:others was approximately 2:4:1:3, confirming that it was a silicone resin primarily composed of a cage structure. Note that T8, T10, and T12 correspond to the structural formulas (1), (2), and (3), respectively, in which R was a methacryloxypropyl group.

[0066] Example 1 A thermosetting silicone resin composition 1 was obtained by mixing 30 parts by weight of the cage-type silicone resin (A-1) of Synthesis Example 1 having methacryloxypropyl groups on all of the silicon atoms as the reactive silicone resin component (A), 70 parts by weight of a 65:35 (weight ratio) mixture of dipentaerythritol hexaacrylate (Mw=578.57, number of acrylic groups=6) and dipentaerythritol pentaacrylate (Mw=524.52, number of acrylic groups=5) as the polyfunctional (meth)acrylate monomer (B) containing at least three (meth)acryloyl groups in the molecule (product name DPHA, manufactured by Kyoeisha Chemical Co., Ltd.) (B-1), and 3 parts by weight of 1,1-di(t-butylperoxy)cyclohexane (C-1) having the chemical structure shown below (product name Perhexa C, manufactured by NOF Corporation) as the organic peroxide (C). For the resulting thermosetting silicone resin composition 1, the number of (meth)acrylic moles of component (B) per 100 g was {[100 × (6 / 578.57) × 0.65] + [100 × (5 / 524.52) × 0.35]} × (70 / 103) = 0.69.

[0067] Next, the obtained thermosetting silicone resin composition 1 was diluted with propylene glycol monomethyl ether to a solids content of 40 parts by weight, and 0.5 parts by weight of an acrylic surface conditioner (BYK Corporation, product name BYK3440) was mixed in. This mixture was applied to one side of a cyclic olefin copolymer resin substrate (thickness 3 mm, length 65 mm, width 35 mm, Mitsui Chemicals, product name APL5014) using a spin coater in the atmosphere so that the film thickness after drying and curing was 5 μm. The mixture was then dried at 80 ° C. for 5 minutes to form a coating layer. The coating layer was then cured by heating at 120 ° C. for 2 hours, and a laminate test piece was obtained in which a cured coating layer made of the thermosetting silicone resin composition was formed on the surface of the cyclic olefin copolymer resin substrate.

[0068] [Examples 2 to 9, Comparative Examples 1 to 4] Thermosetting silicone resin compositions and laminate test pieces were obtained in the same manner as in Example 1, except that the raw materials and compositional ratios shown in Tables 1 and 2 were used. Other abbreviations in the tables refer to the following:

[0069] Polyfunctional (meth)acrylic monomer (B) containing at least three (meth)acryloyl groups in the molecule: B-2: trimethylolpropane triacrylate (Mw = 296.32, number of acrylic groups = 3, manufactured by Kyoeisha Chemical Co., Ltd., product name Light Acrylate TMP-A)

[0070] (Meth)acrylic monomer other than the polyfunctional (meth)acrylic monomer (B) containing at least three (meth)acryloyl groups in the molecule B'-3: dimethyloltricyclodecane diacrylate (Mw=304.39, number of acrylic groups=2, manufactured by Kyoeisha Chemical Industry Co., Ltd., trade name Light Acrylate DCP-A) For ease of comparison, B'-3 is listed as (B) in Tables 1 and 2.

[0071] Organic peroxide (C) C-2: t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, product name Perbutyl O) C-3: 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, product name Perocta O)

[0072] Polymerization initiator other than organic peroxide (C) C'-4: 2,2'-azodiisobutyronitrile (manufactured by Fujifilm, product name AIBN) For ease of comparison, C'-4 is shown as (C) in Tables 1 and 2.

[0073] Inorganic filler (D) D-1: Alumina (particle shape: plate-like, particle size: 20 nm x 20 nm, manufactured by Kawaken Fine Chemicals, product name: Organoalumina Sol)

[0074] Example 10 A thermosetting silicone resin composition and a laminate test piece were obtained in the same manner as in Example 1, except that the raw materials and compositional ratios shown in Table 1 were used and the curing conditions for the thermosetting silicone resin composition were changed to 110°C for 4 hours.

[0075] The laminate test pieces obtained above were subjected to the following evaluations, and the evaluation results are shown in Tables 1 and 2.

[0076] [Adhesion] One hundred 1 mm x 1 mm squares were made on the cured film surface of each laminate test piece in accordance with JIS K 5600-5-6 (1990), and adhesive tape was applied to the surface and rapidly peeled off. This process was repeated three times, and the degree of peeling was evaluated based on the remaining state of the squares using the following criteria: ◯: 100 squares remaining △: 90 to 99 squares remaining ×: 0 to 89 squares remaining

[0077] [Pencil Hardness] According to JIS K 5600, the surface of the cured film of each laminate test piece was scratched at an angle of 45 degrees with a Mitsubishi Uni Pencil under a load of 750 g, and the hardness at which scratches were not produced was visually determined.

[0078]

[0079]

Claims

1. A thermosetting silicone resin composition used as a cured coating layer on a cyclic olefin resin substrate, comprising a compound represented by the general formula (1): [RSiO ３ / ２ ] ｎ (1) A thermosetting silicone resin composition comprising: a reactive silicone resin (A) represented by the formula (wherein R is an organic functional group having a (meth)acryloyl group, and n is 8, 10, or 12), the reactive silicone resin (A) containing, as a main component, a polyorganosilsesquioxane having a cage structure in its structural unit; a polyfunctional (meth)acrylate monomer (B) containing at least three (meth)acryloyl groups in its molecule; and an organic peroxide (C); wherein, relative to 100 parts by weight of the total of components (A), (B), and (C), the composition contains 24 to 80 parts by weight of component (A), 19 to 75 parts by weight of component (B), and 0.5 to 10 parts by weight of component (C); and wherein the total number of (meth)acrylic moles of the polyfunctional (meth)acrylate monomer (B) containing at least three (meth)acryloyl groups in its molecule, contained in 100 g of the composition, is 0.20 to 0.

75.

2. The heat-curable silicone resin composition according to claim 1, wherein the organic peroxide (C) generates tert-butoxy radicals upon heating.

3. The heat-curable silicone resin composition according to claim 1, further comprising an inorganic filler (D) having a primary particle size of 1 to 100 nm in an amount of 1 to 50 parts by weight per 100 parts by weight of the total of components (A) and (B).

4. A laminate having a cured coating layer made from the heat-curable silicone resin composition according to any one of claims 1 to 3 on a cyclic olefin resin substrate.

5. The laminate according to claim 4, wherein the cyclic olefin resin substrate is not subjected to an easy-adhesion treatment.

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