Photocurable silicone resin composition, silicone resin molded article obtained by curing the composition, and method for producing the molded article

Abstract

To provide a photocurable silicone resin composition which can give a molding that has high pencil hardness, and is excellent in scratch resistance and bending resistance, and a silicone resin molding that is a three-dimensional crosslinked body obtained by curing the same.SOLUTION: A photocurable silicone resin composition is obtained by blending a reactive silicone resin (A), a polyfunctional alkylene oxide-modified unsaturated compound (B) that contains at least two unsaturated groups represented by -R3-CR4=CH2 or -CR4=CH2 in one molecule, in the formula, R3 represents an alkylene group, an alkylidene group or a -O-C(=O)- group, and R4 represents a hydrogen atom or an alkyl group, and further has an alkylene oxide-modified part, and a polyfunctional unsaturated compound (C) that contains the two or more unsaturated groups in one molecule and does not contain an alkylene oxide-modified part in a mass ratio of 1 to 50:10 to 40:10 to 80.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photocurable silicone resin composition capable of giving a molded article having high pencil hardness and excellent scratch resistance and flex resistance, and to a silicone resin molded article which is a three-dimensionally crosslinked body obtained by curing the photocurable silicone resin composition. [Background technology]

[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 automobile parts, and plastics and lightweight metals are being used as surface protection materials for these products instead of glass and metal. However, plastics and some lightweight metals have a problem in that they have low surface hardness and are easily scratched. Therefore, a method of providing a hard coat layer to protect the surface is being used.

[0003] Acrylic compositions are often used for such hard coat layers. Acrylic compositions are generally formed and cured by radical reactions caused by irradiation with active energy rays such as ultraviolet rays and electron beams, and therefore can be cured in a short time at low temperatures and can maintain toughness depending on the resin composition blended, and therefore are widely used in paints, adhesives, etc.

[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 the reactive silicone resin having a cage structure and blending an unsaturated compound capable of radical copolymerization with this resin 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, and dimensional stability, and that can be suitably used as a substitute for inorganic glass (Patent Documents 1-2). In addition, a method for producing such a reactive silicone resin having a cage structure is particularly disclosed in Patent Document 3.

[0005] However, although such silicone resin compositions have high surface hardness, they have problems such as the occurrence of cracks and peeling when bent. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4558643 [Patent Document 2] Patent No. 5698566 [Patent Document 3] JP 2004-143449 A Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a photocurable silicone resin composition from which a molded article having high pencil hardness and excellent scratch resistance and flex resistance can be obtained, and to provide a silicone resin molded article which is a three-dimensional crosslinked body obtained by curing the photocurable silicone resin composition. [Means for solving the problem]

[0008] The present inventors have discovered that the above problems can be solved by including in the photocurable silicone resin composition, in particular, a polymerizable compound having a specific structure as the radically polymerizable unsaturated compound in the composition, in a specific ratio, and have thus arrived at the present invention.

[0009] That is, the present invention relates to a reactive silicone resin (A) and a compound having -R 3 -CR 4 =CH2 or -CR 4 =CH2 [where R 3 represents an alkylene group, an alkylidene group, or an -OC(=O)- group; R 4represents a hydrogen atom or an alkyl group] and further having an alkylene oxide modified moiety, and a polyfunctional unsaturated compound (C) containing two or more of the unsaturated groups in one molecule and not containing an alkylene oxide modified moiety, in a mass ratio of 1-50:10-40:10-80. Effect of the Invention

[0010] According to the present invention, it is possible to provide a photocurable silicone resin composition which can give a molded article having high pencil hardness and excellent scratch resistance and flex resistance, and a silicone resin molded article which is a three-dimensional crosslinked body obtained by curing the photocurable silicone resin composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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 invention. In this specification, when the expression "~" is used, it is used as an expression including the numerical value or physical property value before and after it. In addition, when the expression "(meth)acrylic" is used in the present invention, it means one or both of "acrylic" and "methacrylic". The same applies to "(meth)acrylate" and "(meth)acryloyl".

[0012] The photocurable silicone resin composition of the present invention comprises a reactive silicone resin (A) and a -R 3 -CR 4 =CH2 or -CR 4 =CH2 [where R 3 represents an alkylene group, an alkylidene group, or an -OC(=O)- group; R 4represents a hydrogen atom or an alkyl group] and further having an alkylene oxide modified moiety, and a polyfunctional unsaturated compound (C) containing two or more of the unsaturated groups in one molecule and not containing an alkylene oxide modified moiety, in a mass ratio of 1-50:10-40:10-80.

[0013] The reactive silicone resin (A) used in the present invention is preferably blended in a mass ratio of 1 to 50 parts by mass, more preferably 2.5 to 30 parts by mass, per 100 parts by mass of the photocurable silicone resin composition. If the amount is less than 1 part by mass, the crosslink density decreases, the composition becomes soft, and the scratch resistance and pencil hardness deteriorate. If the amount is more than 50 parts by mass, the crosslink density increases, the composition becomes hard and brittle, and cracks and peeling occur when flexed.

[0014] The reactive silicone resin (A) may be a known silicone resin, but a preferred embodiment is represented by the following general formula (1), and is mainly composed of polyorganosilsesquioxane having a cage structure in the structural unit (also called cage polyorganosilsesquioxane. Polyorganosilsesquioxane is also called silsesquioxane). In general formula (1), R is an organic functional group having a (meth)acryloyl group, and n is 8, 10, or 12. [RSiO 3 / 2 ] n (1) In the general formula (1), R is an organic functional group having a (meth)acryloyl group, and n is 8, 10, or 12. The organic functional group having a (meth)acryloyl group can be exemplified by a group represented by the following general formula (4). In the general formula (4), m is an integer of 1 to 3, and R 1 is a hydrogen atom or a methyl group. CH2=CR 1 -COO-(CH2) m - (4)

[0015] Such reactive silicone resins have organic functional groups having (meth)acryloyl groups on silicon atoms in the molecule. Specific structures of cage-type polyorganosilsesquioxanes in which n in general formula (1) is 8, 10, or 12 include cage-type structures shown in the following structural formulas (5), (6), and (7), respectively. Note that R in the following formulas represents the same as R in general formula (1).

[0016] [ka]

[0017] Here, such reactive silicone resins can be produced by the method described in the above Patent Document 3, etc. For example, a silicon compound represented by RSiX3 is hydrolyzed and partially condensed in the presence of a polar solvent and a basic catalyst, and the obtained hydrolysis product is further recondensed in the presence of a non-polar solvent and a basic catalyst to obtain the reactive silicone resin. Here, R is an organic functional group having a (meth)acryloyl group, specifically a group represented by the above general formula (4), and X represents a hydrolyzable group. Specific examples of preferred R include a 3-methacryloxypropyl group, a methacryloxymethyl group, and a 3-acryloxypropyl group.

[0018] The hydrolyzable group X is not particularly limited as long as it is a group having hydrolyzability, and examples thereof include an alkoxy group, an acetoxy group, etc., but is preferably an alkoxy group. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n- or i-propoxy group, or an n-, i-, or t-butoxy group, etc. A methoxy group is preferred because of its high reactivity.

[0019] Among the silicon compounds represented by RSiX3, preferred compounds include methacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane, 3-methacryloxypropyltrichlorosilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-acryloxypropyltrichlorosilane. Among them, it is preferable to use 3-methacryloxypropyltrimethoxysilane, which is an easily available raw material.

[0020] Examples of the basic catalyst 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 preferably used because of its high catalytic activity. The basic catalyst is usually used as an aqueous solution.

[0021] 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 is slow and the hydrolyzable groups remain in an unreacted state, resulting in a long reaction time. On the other hand, if the reaction temperature is higher than 60°C, the reaction rate is too fast, so a complex condensation reaction proceeds, and as a result, the hydrolysis product is promoted to have a high molecular weight. 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, and the hydrolyzable groups may remain in an unreacted state.

[0022] The presence of water is essential for the hydrolysis reaction, and this can be supplied from an aqueous solution of a basic catalyst, or water can be added separately. The amount of water should be at least an amount sufficient to hydrolyze the hydrolyzable group, and is preferably 1.0 to 1.5 times the theoretical amount. In addition, it is necessary to use an organic polar solvent during hydrolysis, and as the organic polar solvent, alcohols such as methanol, ethanol, and 2-propanol, or other organic polar solvents can be used. Preferably, it is a lower alcohol having 1 to 6 carbon atoms that is soluble in water, and more preferably, 2-propanol is used. If a non-polar solvent is used, the reaction system will not be homogenous, the hydrolysis reaction will not proceed sufficiently, and unreacted hydrolyzable groups will remain, which is not preferable.

[0023] After the hydrolysis reaction is completed, water or a water-containing reaction solvent is separated. For the separation of water or a water-containing reaction solvent, a means such as evaporation under reduced pressure can be used. In order to sufficiently remove moisture and other impurities, a means such as adding a non-polar solvent to dissolve the hydrolysis reaction product, washing the solution with saline or the like, and then drying with a drying agent such as anhydrous magnesium sulfate can be used. If the non-polar solvent is separated by a means such as evaporation, the hydrolysis reaction product can be recovered, but if the non-polar solvent can be used as a non-polar solvent for the next reaction, it is not necessary to separate it.

[0024] In the hydrolysis reaction, a condensation reaction of the hydrolyzate occurs along with the hydrolysis. The hydrolysis product accompanied by the condensation reaction of the hydrolyzate is usually a colorless viscous liquid with a number average molecular weight of 1400 to 5000. The hydrolysis product becomes an oligomer with a number average molecular weight of 1400 to 3000, depending on the reaction conditions, in which most, preferably almost all, of the hydrolyzable groups X are replaced with OH groups, and most, preferably 95% or more, of the OH groups are condensed. The structures of the hydrolysis products are multiple types of cage-type, ladder-type, and random-type silsesquioxanes, and even in compounds that have a cage structure, the proportion of a complete cage structure is low, and an incomplete cage structure in which a part of the cage is open is predominant. Therefore, the hydrolysis product obtained by this hydrolysis is further heated in an organic solvent in the presence of a basic catalyst to condense (re-condense) the siloxane bonds, thereby selectively producing a cage-type silsesquioxane.

[0025] Specifically, the reaction is carried out as follows. That is, after the hydrolysis reaction is completed as described above, water or a water-containing reaction solvent is separated, and then a recondensation reaction is carried out in the presence of a non-polar solvent and a basic catalyst. Regarding the reaction conditions of the recondensation reaction, the reaction temperature is preferably in the range of 100 to 200°C, and more preferably 110 to 140°C. 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 a self-polymerization reaction, 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 the non-polar solvent used should be sufficient to dissolve the hydrolysis reaction product, and the amount of the basic catalyst used should be in the range of 0.1 to 10% by mass (wt%) relative to the hydrolysis reaction product.

[0026] The non-polar solvent may be one that is not or barely soluble in water, but is preferably a hydrocarbon solvent. Examples of such a hydrocarbon solvent include non-polar solvents with low boiling points such as toluene, benzene, and xylene. Of these, it is preferable to use toluene. As the basic catalyst, the basic catalyst used in the hydrolysis reaction can be used, and examples of the basic catalyst 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, but a catalyst soluble in a non-polar solvent such as tetraalkylammonium is preferable.

[0027] In addition, the hydrolysis product used in the recondensation is preferably washed with water, dehydrated, and concentrated, but can be used without washing with water or dehydration. During this reaction, water may be present, but it is not necessary to actively add it, and it is better to limit the amount of water to that brought in from the basic catalyst solution. If the hydrolysis product is not sufficiently hydrolyzed, water is required in an amount greater than the theoretical amount required to hydrolyze the remaining hydrolyzable groups, but the hydrolysis reaction is usually sufficiently carried out. After the recondensation reaction, the catalyst is washed with water to remove it, and the mixture is concentrated to obtain a silsesquioxane mixture. The obtained silsesquioxane mixture is preferably one in which the number of silicon atoms in the molecule is equal to the number of (meth)acryloyl groups.

[0028] The silsesquioxane mixture thus obtained varies depending on the reaction conditions and the state of the hydrolysis product, but the components are considered to be 70% or more of the total of multiple cage-type silsesquioxanes, and the rest are ladder-type and random-bridged silsesquioxanes. Since these are difficult to separate and require a lot of time, in the present invention, when using a cage-type silsesquioxane represented by general formula (1), it is preferable to use a silsesquioxane containing multiple cage-type silsesquioxanes at 70% or more. Note that there is no difference in the effect obtained as long as the cage-type silsesquioxane content is 70% or more. The components of the multiple cage-type silsesquioxanes are T8 represented by general formula (5) at 20 to 40%, T10 represented by general formula (6) at 40 to 50%, and the other components are T12 represented by general formula (7). T8 can be separated by precipitating as needle-shaped crystals by leaving the silsesquioxane mixture at 20°C or less. Note that the content ratio of the cage-type silsesquioxane can be confirmed using, for example, GPC, LC-MS, etc.

[0029] Such a reactive silicone resin may be a mixture of T8 to T12, or may be one in which T8 or T2 has been separated or concentrated, but is not limited to the reactive silicone resin obtained by the above-mentioned production method.

[0030] The polyfunctional alkylene oxide modified unsaturated compound (B) has -R 3 -CR 4 =CH2 or -CR 4 =CH2 [where R 3 represents an alkylene group, an alkylidene group, or an -OC(=O)- group; R 4 represents a hydrogen atom or an alkyl group] and has an alkylene oxide modified moiety. Here, the alkylene oxide modified moiety is preferably ethylene oxide or propylene oxide. It is also preferable that at least one alkylene oxide modified moiety is contained for each unsaturated group. By containing component (B), it is possible to suppress cracking and peeling during bending while maintaining a high surface hardness.

[0031] The polyfunctional alkylene oxide-modified unsaturated compound (B) is preferably blended in a mass ratio of 10 to 40 parts by mass relative to 100 parts by mass of the photocurable silicone resin composition, and more preferably in a mass ratio of 10 to 30 parts by mass. If the amount is less than 10 parts by mass, sufficient flexibility cannot be imparted, causing cracks and peeling upon bending, whereas if the amount is more than 40 parts by mass, the surface hardness decreases, causing decreases in pencil hardness and scratch resistance.

[0032] Examples of the polyfunctional alkylene oxide-modified unsaturated compound (B) include alkylene oxide-modified glycerin tri(meth)acrylate, alkylene oxide-modified diglycerin tetra(meth)acrylate, alkylene oxide-modified dipentaerythritol tetra(meth)acrylate, alkylene oxide-modified dipentaerythritol hexa(meth)acrylate, polyethylene glycol acrylate, polypropylene glycol acrylate, etc. These (B) components may be used alone or in combination of two or more.

[0033] Specifically, trimethylolpropane triacrylate modified with 3 moles of ethylene oxide, trimethylolpropane triacrylate modified with 6 moles of ethylene oxide, trimethylolpropane triacrylate modified with 9 moles of ethylene oxide, trimethylolpropane triacrylate modified with 3 moles of propylene oxide, pentaerythritol tetraacrylate modified with 4 moles of ethylene oxide, pentaerythritol tetraacrylate modified with 5 moles of ethylene oxide, dipentaerythritol hexaacrylate modified with 6 moles of ethylene oxide, dipentaerythritol hexaacrylate modified with 12 moles of ethylene oxide, ethylene oxide, Examples of the compound include glycerin triacrylate modified with 3 moles of silane, glycerin triacrylate modified with 3 moles of propylene oxide, diglycerin tetraacrylate modified with 4 moles of ethylene oxide, triethylene glycol diacrylate, polyethylene glycol diacrylate, bisphenol A diacrylate modified with 3 moles of ethylene oxide, bisphenol A diacrylate modified with 4 moles of ethylene oxide, bisphenol A diacrylate modified with 10 moles of ethylene oxide, bisphenol F diacrylate modified with 4 moles of ethylene oxide, polyethylene glycol diacrylate, polypropylene glycol diacrylate, etc. Among these compounds, from the viewpoint of surface hardness, those having three or more of the photopolymerizable unsaturated groups are more preferable, and from the viewpoint of suppressing cracks and peeling during bending, it is preferable to use a polyfunctional alkylene oxide modified unsaturated compound containing at least one alkylene oxide moiety per unsaturated group.

[0034] The polyfunctional unsaturated compound (C) that does not contain an alkylene oxide modified site has -R 3 -CR 4 =CH2 or -CR 4 =CH2 [where R 3 represents an alkylene group, an alkylidene group, or an -OC(=O)- group; R 4 represents a hydrogen atom or an alkyl group), preferably contains at least two unsaturated groups, and more preferably is a polyfunctional unsaturated compound containing hydroxyl groups in an amount of 20 mass % or more out of 100 mass % of component (C).

[0035] The polyfunctional unsaturated compound (C) not containing an alkylene oxide modified portion is preferably used in a mass ratio of 10 to 80, more preferably 30 to 80, based on 100 parts by mass of the photocurable silicone resin composition. If it is less than 10 parts by mass, crosslinking becomes insufficient, and scratch resistance and pencil hardness deteriorate. If it is more than 80 parts by mass, the crosslinking density increases, making the composition hard and brittle, and cracking or peeling occurs when flexed.

[0036] The polyfunctional unsaturated compound (C) not containing an alkylene oxide modified portion preferably contains 10 to 100 mass % of a polyfunctional unsaturated compound having two or more or three or more unsaturated groups. By blending such a polyfunctional unsaturated compound, a molded article having high surface hardness can be obtained.

[0037] Examples of unsaturated compounds containing a hydroxyl group among the above polyfunctional unsaturated compounds include pentaerythritol triacrylate, glycerin dimethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetraacrylate, etc. These compounds have hydroxyl groups in their molecules, and therefore the distance between the molecules is shortened due to the interaction of the hydroxyl groups, and the radicals generated react quickly with the double bonds, improving the curing rate, and radical polymerization proceeds prior to the reaction between oxygen and radicals, making it possible to suppress curing inhibition caused by oxygen. As described above, it is preferable that 20% by mass or more of the polyfunctional unsaturated compound (C) not containing an alkylene oxide modified portion to be blended in the present silicone resin composition is an unsaturated compound containing a hydroxyl group, and more preferably 30% by mass or more of (C) is an unsaturated compound containing a hydroxyl group. Within this range, the interaction between molecules is effective. There is no particular upper limit to the blending amount, but if it exceeds 60% by mass, the increase in the oxygen inhibition suppression effect is almost eliminated.

[0038] On the other hand, examples of polyfunctional unsaturated compounds not containing hydroxyl groups include trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, etc. In addition to these, some or all of the hydroxy groups of pentaerythritol or dipentaerythritol are modified with glycols such as ethylene or isopropylene, γ-butyrolactone, etc., and all of the terminal hydroxy groups of the resulting skeleton are further modified with -R 3 -CR 4 =CH2 or -CR 4 =CH2 [where R 3 represents an alkylene group, an alkylidene group, or an -OC(=O)- group; R 4 It is also possible to use compounds modified with an unsaturated group represented by the formula (I) (wherein represents a hydrogen atom or an alkyl group). Other examples include urethane acrylate and acrylic copolymer acrylate. These polyfunctional unsaturated compounds and unsaturated compounds not containing a hydroxyl group may be used alone or in combination of two or more.

[0039] In addition, the polyfunctional unsaturated compound (C) that does not contain an alkylene oxide modified portion may contain reactive monofunctional or other bifunctional monomers (unsaturated compounds) within a range that does not reduce the surface hardness. Examples of monofunctional monomers include styrene, vinyl acetate, N-vinylpyrrolidone, butyl acrylate, 2-ethylhexyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-decyl acrylate, isobornyl acrylate, dicyclopentenyloxyethyl acrylate, phenoxyethyl acrylate, and trifluoroethyl methacrylate. Examples of other bifunctional monomers include tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, bisphenol A diglycidyl ether diacrylate, tetraethylene glycol diacrylate, and hydroxypivalic acid neopentyl glycol diacrylate. The monofunctional monomer or other bifunctional monomer is preferably contained in the polyfunctional unsaturated compound (C) not containing an alkylene oxide modified portion in an amount of 20% by mass or less, more preferably 10% by mass or less. If it is blended in an amount of more than 20% by mass, the surface hardness tends to decrease, which is not preferable.

[0040] The photocurable silicone resin composition of the present invention preferably further contains an active energy ray polymerization initiator (D). The active energy ray polymerization initiator (D) is 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass, per 100 parts by mass of the photocurable silicone resin composition. If the amount is less than this range, crosslinking and deterioration of scratch resistance and pencil hardness are suppressed. On the other hand, even if the amount exceeds this range, further improvement in the reaction rate may not be expected.

[0041] As the active energy ray polymerization initiator (D), for example, a benzoin-based, acetophenone-based, anthraquinone-based, thioxanthone-based, ketal-based, or phosphine oxide-based compound can be suitably used. In addition, a photoinitiator assistant or a photosensitizer that exerts an effect in combination with the photoinitiator can also be used.

[0042] Specific examples of the active energy ray polymerization initiator (D) include photoinitiators such as benzoin-based initiators, such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; acetophenone-based initiators such as acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one; and 2-ethylanthraquinone. , anthraquinones such as 2-tertiary butyl anthraquinone, 2-chloro anthraquinone, 2-amyl anthraquinone; thioxanthones such as 2,4-diethyl thioxanthone, 2-isopropyl thioxanthone, 2-chloro thioxanthone; ketals such as acetophenone dimethyl ketal, benzyl dimethyl ketal; benzophenones such as benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 4,4'-bismethylaminobenzophenone; phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, etc. These can be used alone or in a mixture of two or more kinds, and can be further used in combination with a photoinitiator assistant such as a tertiary amine such as triethanolamine, methyldiethanolamine, etc., or a benzoic acid derivative such as N,N-dimethylaminobenzoic acid ethyl ester, N,N-dimethylaminobenzoic acid isoamyl ester, etc.

[0043] As the photosensitizer, naphthalene-based agents such as 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-di(n-propoxy)naphthalene, 1,4-di(i-propoxy)naphthalene, 2,6-dimethoxynaphthalene, 2,6-diethoxynaphthalene, 2,6-di(n-propoxy)naphthalene, and 2,6-di(i-propoxy)naphthalene, and benzophenone-based agents such as benzophenone, 4-methylbenzophenone, 4-(methylphenylthio)phenyl]-phenylmethane, and 4,4'-bis(diethylamino)benzophenone can be preferably mentioned. The blending amount is in the range of 0.05 to 3 parts by mass, preferably 0.1 to 3 parts by mass, based on the photocurable silicone resin composition from the viewpoint of photocurability and transparency. If it is less than 0.05 parts by mass, the improving effect of the sensitizer is not exhibited, and the expected hardness improving effect is not obtained. If the amount exceeds 3 parts by mass, coloring tends to become strong, so it is preferable to use the photosensitizer within the above range. A plurality of photosensitizers may be combined to adjust the photocurability and transparency.

[0044] The photocurable silicone resin molded article of the present invention can be produced by curing the above-mentioned photocurable silicone resin composition by irradiation with active energy rays such as visible light, ultraviolet light, and electron beams, and preferably by irradiation with ultraviolet light having a wavelength of 10 to 400 nm or visible light having a wavelength of 400 to 700 nm, a cured molded article can be obtained. The wavelength of the light used is not particularly limited, but near ultraviolet light having a wavelength of 200 to 400 nm is particularly preferably used. Examples of lamps used as ultraviolet light generating sources include low-pressure mercury lamps (output: 0.4 to 4 W / cm), high-pressure mercury lamps (40 to 160 W / cm), ultra-high-pressure mercury lamps (173 to 435 W / cm), and metal halide lamps (80 to 160 W / cm).

[0045] The method of obtaining a molded body (silicone resin copolymer or cured product) by irradiation with active energy rays such as light irradiation may be either in an oxygen-blocking atmosphere or in an air atmosphere, but since the composition of the present invention can give a good molded body even when polymerized and cured in an air atmosphere, it is preferable to carry out the method in an air atmosphere.For example, the photocurable silicone resin composition of the present invention is injected into a mold having an arbitrary cavity shape and made of a transparent material such as quartz glass, and polymerized and cured by irradiating with ultraviolet light from an ultraviolet lamp, and then demolded from the mold to produce a molded body of a desired shape; when no mold is used, the photocurable silicone resin composition of the present invention is applied on a moving steel belt using a doctor blade or a roll-shaped coater, and polymerized and cured by an ultraviolet lamp to produce a sheet-shaped molded body. The shape of the molded product is arbitrary, and may be a film, a coating, or the like. The molded product is obtained by radically copolymerizing and curing the photocurable silicone resin composition of the present invention. The molded product or cured product of the present invention is a three-dimensional crosslinked polymer, and in this case, the same molding and curing method as for thermosetting resins can be used.

[0046] Further, the photocurable silicone resin composition of the present invention may be applied to various substrates such as polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), triacetyl cellulose (TAC), transparent polyimide (CPI), polyimide (PI), metal plate, and glass, or may be diluted with various organic solvents and applied and cured to form a molded body as a hard coat film on the substrate surface. Specific examples include the dripping method, roller coating method, bar coating method, spray coating 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 solid content concentration, taking into consideration the formed film thickness after drying and curing with an ultraviolet lamp. When an organic solvent is used to adjust the solid content concentration, it is preferable to remove the organic solvent by drying or the like after coating. The drying temperature is set to a condition that the substrate used is not deformed, and the drying time is preferably 1 hour or less from the viewpoint of productivity. From the viewpoints of scratch resistance and adhesion, the thickness of the hard coating film is 0.5 to 100 μm, preferably 1 to 60 μm.

[0047] 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.

[0048] Examples of the glycol ether organic solvent 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.

[0049] The laminate (photocurable silicone resin laminate) containing the resin molded product of the present invention thus obtained has a pencil hardness (based on JIS K5600) of 2H or more, preferably 3H or more, and preferably has a scratch resistance of not being scratched by 300 reciprocations under a load of 1,500 g in a steel wool test. In addition, in terms of bending resistance, it is preferable that when a test piece of 80×50 mm square is wrapped around an acrylic cylinder of 50 mm diameter with the layer of the silicone resin molded product on the outside, with the long side of the rectangle aligned with the circumference of the cylinder, the silicone resin molded product does not crack or peel off.

[0050] Various additives can be added to the photocurable silicone resin composition of the present invention within the scope of the object of the present invention. Examples of various additives include organic / inorganic fillers, plasticizers, flame retardants, heat stabilizers, antioxidants, light stabilizers, UV absorbers, leveling agents, slippage imparting agents, antistatic agents, release agents, foaming agents, nucleating agents, colorants, fluorescent brightening agents, crosslinking agents, dispersion aids, resin components, etc. EXAMPLES

[0051] Examples of the present invention will be described below. The reactive silicone resins used in the following examples were obtained by the methods shown in the following synthesis examples.

[0052] [Synthesis Example 1] A reaction vessel equipped with a stirrer, a dropping funnel, and a 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: SZ-6030 manufactured by Toray Dow Corning Silicone Co., Ltd.) were placed in the dropping funnel, and the IPA solution of MTMS was dropped at room temperature over 30 minutes while stirring the reaction vessel. After the dropping of MTMS was completed, the mixture was stirred for 2 hours without heating. After stirring for 2 hours, the solvent was removed under reduced pressure and dissolved in 50 ml of toluene. The reaction solution was washed with saturated saline until it became neutral, and then dehydrated with anhydrous magnesium sulfate. The anhydrous magnesium sulfate was filtered off and concentrated to obtain 25.8 g of the hydrolysis product (silsesquioxane). This silsesquioxane was a colorless viscous liquid that was soluble in various organic solvents. Next, 20.65 g of the silsesquioxane obtained above, 82 ml of toluene, and 3.0 g of 10% TMAH aqueous solution were placed in a reaction vessel equipped with a stirrer, Dinstark, and cooling tube, and gradually heated to distill off water. The mixture was further heated to 130°C, and a recondensation reaction was carried out at the reflux temperature of toluene. The temperature of the reaction solution at this time was 108°C. After 2 hours of stirring after the toluene reflux, the reaction was terminated. The reaction solution was washed with saturated saline until it became neutral, and then dehydrated with anhydrous magnesium sulfate. The anhydrous magnesium sulfate was filtered off and concentrated to obtain 18.77 g of the target cage-type silsesquioxane (mixture). The obtained cage-type silsesquioxane (S1) was a colorless viscous liquid that was soluble in various organic solvents. When the reaction product after the recondensation reaction was separated by liquid chromatography and then subjected to mass spectrometry, it was confirmed that the molecular ions with ammonium ions were attached to the molecular structures of the above structural formulas (5), (6), and (7) in which R was a methacryloyl group, and the composition ratio of T8:T10:T12:others was about 2:4:1:3, confirming that it was a silicone resin mainly composed of a cage structure. Note that T8, T10, and T12 correspond to the structures (5), (6), and (7) in which R was a methacryloyl group, respectively.

[0053] [Example 1] The reactive silicone resin (A) component was 25 parts by mass of the cage-type silicone resin (S1) having methacryloyl groups on all silicon atoms of Synthesis Example 1, and the polyfunctional alkylene oxide-modified unsaturated compound (B) component was 12 mol ethylene oxide-modified dipentaerythritol hexaacrylate (B1) (manufactured by Nippon Kayaku Co., Ltd., product name KAYARAD DPEA). - 12): 20 parts by mass of a 65:35 (mass ratio) mixture (C1) (manufactured by Nippon Kayaku Co., Ltd., product name KAYARAD DPHA) of dipentaerythritol hexaacrylate (Mw=578.57, number of acrylic groups=6, number of hydroxyl groups=0) and dipentaerythritol pentaacrylate (Mw=524.52, number of acrylic groups=5, number of hydroxyl groups=1) as a polyfunctional unsaturated compound (C) component: 55 parts by mass of 1-hydroxycyclohexylphenyl ketone (D1) (manufactured by IGM, product name Omnirad184) as an active energy ray polymerization initiator (D) were mixed to obtain a photocurable silicone resin composition.

[0054] Next, 50 parts by mass of the obtained photocurable silicone resin composition, 50 parts by mass of propylene glycol monomethyl ether as a dilution solvent, and 1 part by mass of a fluorine-based surface conditioner (KY-1203 manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed, and this mixture was applied in air to the polymethyl methacrylate side of a composite plate (thickness 650 μm, length 10 cm, width 10 cm, C001 manufactured by S-Carbo Sheet Co., Ltd.) made of polymethyl methacrylate using a bar coater so that the film thickness after drying would be 10 μm, and then dried at 80° C. for 5 minutes. Thereafter, the mixture was applied in an oxygen atmosphere with an accumulated exposure dose of 2,800 mJ / cm 2 . 2 This resulted in a laminate test piece having a layer of the silicone resin molded product formed on the polymethyl methacrylate surface of the composite plate.

[0055] [Examples 2 to 14, Comparative Examples 1 to 5] A photocurable silicone resin composition was obtained in the same manner as in Example 1, except that the raw materials and compositional ratios shown in Table 1 were used. Other abbreviations in the table represent the following. DGE-4A: Ethylene oxide 4 mole modified diglycerol tetraacrylate (B2) (number of acrylic groups = 4, number of ethylene oxide modifications = 4, Kyoeisha Chemical Co., Ltd.) M3130: Trimethylolpropane triacrylate modified with 3 moles of ethylene oxide (B3) (number of acrylic groups = 3, number of ethylene oxide modifications = 3, manufactured by MIWON) M3190: Trimethylolpropane triacrylate modified with 9 moles of ethylene oxide (B4) (number of acrylic groups = 3, number of ethylene oxide modifications = 9, manufactured by MIWON) M320: propylene oxide 3 mole modified glycerin triacrylate (B5) (number of acrylic groups = 3, number of propylene oxide modifications = 3, manufactured by MIWON) Light Acrylate PE-3A (C2): A 40:60 (mass ratio) mixture of pentaerythritol tetraacrylate (number of acrylic groups = 4, number of hydroxyl groups = 0) and pentaerythritol triacrylate (number of acrylic groups = 3, number of hydroxyl groups = 1) (manufactured by Kyoeisha Chemical Co., Ltd.) Light Acrylate TMP-A (C'1): Trimethylolpropane triacrylate (number of acrylic groups = 3, number of hydroxyl groups = 0, manufactured by Kyoeisha Chemical Co., Ltd.)

[0056] [evaluation] The laminate test pieces obtained above were used to carry out the following evaluations, and the evaluation results are shown in Tables 1 to 3.

[0057] [Pencil hardness] In accordance with JIS K 5600, the surface of the laminate test piece on the side of the silicone resin molded body was scratched at an angle of 45 degrees with a Mitsubishi Pencil Uni with a load of 750 g, and the hardness without scratching was judged visually.

[0058] [Scratch resistance] Using #0000 steel wool, a reciprocating abrasion tester (Type:30S, manufactured by HEIDON) was used, with a load of 1.5 kg / cm 2 The surface of the laminate test piece facing the silicone resin molded body was abraded with a 1 mm or more scratch. Scratches were judged to be scratches if they were 1 mm or longer in length, and the presence or absence of scratches was visually observed under a fluorescent lamp, and the number of scratches was evaluated according to the following criteria. ◎: No scratches after 1,000 passes 〇: No scratches after 300 round trips △: Less than 10 scratches after 300 round trips ×: 10 or more scratches after 300 round trips

[0059] [Bending resistance] The laminate test pieces were cut into 80 x 50 mm squares, and each was wrapped around an acrylic cylinder with a diameter of 50 mm, with the silicone resin molded body side facing outward, with the long side of the rectangle running along the circumference of the cylinder, and the silicone resin molded body was visually observed for deformation or cracks. ○: No cracks or peeling ×: Cracks or peeling occurs

[0060] [Table 1]

[0061]

Table 2

[0062]

Table 3

Claims

1. A reactive silicone resin (A); -R in one molecule ３ -CR ４ = CH2 [wherein R ３ represents an —O—C(═O)— group, and R ４ represents a hydrogen atom or an alkyl group], and further having an alkylene oxide modified site; and a polyfunctional unsaturated compound (C) containing two or more of the unsaturated groups in one molecule and not containing an alkylene oxide modified site, in a mass ratio of 1-50:10-40:10-80 based on 100 parts by mass of the total of the components (A), (B), and (C), The reactive silicone resin (A) is 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 the structural unit contains 70% or more of polyorganosilsesquioxane having a cage structure, A photocurable silicone resin composition characterized in that the polyfunctional unsaturated compound (C) contains at least two unsaturated groups represented by -R 3 -CR 4 ═CH 2 [wherein R 3 represents an -O-C(═O)- group, and R 4 represents a hydrogen atom or an alkyl group] in the molecule, and further, 20% by mass or more of 100% by mass of component (C) is a polyfunctional unsaturated compound containing a hydroxyl group.

2. The polyfunctional alkylene oxide modified unsaturated compound (B) has a -R ３ -CR ４ = CH2 [wherein R ３ represents an —O—C(═O)— group, and R ４ represents a hydrogen atom or an alkyl group], the alkylene oxide-modified moiety is ethylene oxide or propylene oxide, and the photocurable silicone resin composition according to claim 1 is a polyfunctional alkylene oxide-modified unsaturated compound containing at least one alkylene oxide-modified moiety per unsaturated group.

3. 3. The photocurable silicone resin composition according to claim 1, further comprising an active energy ray polymerization initiator (D).

4. 4. A photocurable silicone resin molded article obtained by radically copolymerizing and curing the photocurable silicone resin composition according to claim 1.

5. 4. A photocurable silicone resin laminate obtained by applying the photocurable silicone resin composition according to claim 1 to a substrate, and then radically copolymerizing and curing the composition.

6. A method for producing a photocurable silicone resin molded article, comprising irradiating the photocurable silicone resin composition according to any one of claims 1 to 3 with active energy rays in the atmosphere to effect radical copolymerization to produce a silicone resin molded article.

Images