Photo- and heat-curable silicone composition and method for producing the cured product

Abstract

To provide a two step curable silicone composition capable of individually and easily controlling first stage curing and second stage curing.SOLUTION: A silicone composition includes: an organopolysiloxane (A) having at least three (meth)acryl groups in one molecule; an organopolysiloxane (B) having at least two alkenyl groups, and no (meth)acryl groups in one molecule; an organohydrogenpolysiloxane (C) having at least two hydrosilyl groups in one molecule; a photopolymerization initiator (D); and a hydrosilylation reaction catalyst (E), where the (meth)acryl group contained in the constituent (A) is 1-15 mmol in 100 g of the composition, the ratio of the number of alkenyl groups in the composition / the number of (meth)acryl groups contained in the constituent (A) is 0.5 or more, and the ratio of the number of hydroxyl groups / the number of alkenyl groups and (meth)acryl groups contained in the constituent (A) and (B) is 0.8-3.0.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photo- and heat-curable silicone composition, and more specifically to a two-stage curing liquid silicone composition that is brought to a semi-cured state by radical curing with ultraviolet light in the presence of a photopolymerization initiator and a hydrosilylation reaction catalyst, and then fully cured by a hydrosilylation reaction upon heating, as well as a method for producing a cured product of said composition. [Background technology]

[0002] Two-stage curing liquid silicone materials are attractive because they allow for separate manufacturing processes. For example, in the encapsulant layer of optical devices, the degree of phosphor dispersion affects light extraction efficiency, so strict control of dispersion is necessary. However, when a heat-curing material is used as the encapsulant, the viscosity of the base material decreases during heat curing, making the phosphor more likely to settle, making it difficult to control dispersion and cure simultaneously. However, using a two-stage curing material for the encapsulant layer allows for consistent phosphor dispersion through the first curing step, and then the second curing step increases hardness to the desired level, allowing for mounting on semiconductor devices. In order to simplify these difficult manufacturing processes and contribute to the development of new, different manufacturing processes, two-stage curing silicone materials have been proposed for a wide range of applications, including adhesive films, optical device encapsulation materials, temporary fixing agents for electronic device components, and adhesives, and research and development into these materials is currently underway.

[0003] Patent Document 1 reports that a liquid silicone composition containing an alkenyl group-containing organopolysiloxane, a platinum catalyst for hydrosilylation reactions, and a high-energy ray-activated platinum catalyst is subjected to a heated environment from room temperature to cause primary curing through an addition reaction, yielding a thermoplastic silicone that does not flow in a room temperature environment, and that the thermoplastic silicone is then irradiated with high-energy rays, followed by a heated environment from room temperature to cause a further hydrosilylation reaction, thereby yielding a highly hardened cured silicone product.

[0004] Patent Document 2 reports that a liquid silicone adhesive composition containing an alkenyl group-containing organopolysiloxane, a hydrosilylation reaction catalyst, and a thermal radical reaction initiator is exposed to an environment ranging from room temperature to 100°C to carry out a first-stage curing by addition reaction, yielding a silicone cured product, and that the resulting silicone cured product is then exposed to an environment at a temperature higher than the first-stage curing temperature, such as 150 to 190°C, to carry out a second-stage curing by thermal radical reaction, yielding a silicone cured product with increased hardness.

[0005] Patent Document 3 reports that a liquid silicone adhesive composition containing an organopolysiloxane having a condensation reactive group, an alkenyl group-containing organopolysiloxane, a condensation reaction catalyst, and a thermal radical reaction initiator is subjected to a condensation reaction in the presence of moisture to carry out a first-stage curing to obtain a silicone cured product, and that the resulting silicone cured product is then subjected to a heated environment to carry out a second-stage curing by a thermal radical reaction, thereby obtaining a silicone cured product with a high hardness.

[0006] The methods described in Patent Documents 1 and 2 employ a curing mechanism that begins with heating for both the first and second curing stages. It is generally difficult to control the state of the thermal curing process during the process, and therefore, in order to reproducibly obtain the cured state of the silicone cured product obtained by the first curing, it is necessary to strictly control the temperature profile, making the methods described in Patent Documents 1 and 2 difficult to use in practice. On the other hand, the method described in Patent Document 3 involves first curing by a condensation reaction, which generally generates a large amount of outgassing components, followed by thermal radical curing, which may result in problems such as reversion or cracking due to the evaporation of outgassing components. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2019 / 088066 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-191629 [Patent Document 3] International Publication No. 2018 / 186165 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above circumstances, and has as its object to provide a two-stage curing silicone composition in which the first and second stages of curing can be controlled separately and simply. [Means for solving the problem]

[0009] As a result of extensive research aimed at solving the above-mentioned problems, the present inventors have discovered that a composition containing a (meth)acrylic group-containing organopolysiloxane, an alkenyl group-containing organopolysiloxane, and an organohydrogenpolysiloxane in specified ratios can undergo a first-stage light-induced curing and a second-stage heat-induced curing in the presence of a photopolymerization initiator and a hydrosilylation reaction catalyst, which can be controlled separately and simply, thereby completing the present invention.

[0010] That is, the present invention is 1. (A) an organopolysiloxane having at least three (meth)acrylic groups per molecule; (B) an organopolysiloxane having at least two alkenyl groups in one molecule and no (meth)acrylic group; (C) an organohydrogenpolysiloxane having at least two hydrosilyl groups in one molecule; (D) a photoinitiator, and (E) Hydrosilylation reaction catalyst Contains the (meth)acrylic group contained in the component (A) is 1 to 15 mmol per 100 g of the composition, the ratio of the number of alkenyl groups in the composition to the number of (meth)acrylic groups contained in component (A) is 0.5 or more, a photo- and thermo-curable silicone composition in which the ratio of the number of hydrosilyl groups to the number of alkenyl groups and (meth)acrylic groups contained in components (A) and (B) is 0.8 to 3.0; 2. The photo- and thermo-curable silicone composition according to 1, wherein the component (A) is the following (Ai), (A-ii), or both: (Ai) Organopolysiloxane represented by the following formula (1): [ka] (In the formula, R 1 are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and R 2 each independently represents an oxygen atom or an alkylene group having 1 to 20 carbon atoms; R 3 are each independently an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group; k is an integer of 0 to 1,000; m is an integer of 0 to 20; a and b are each independently an integer of 0 to 3; and a+b+m is an integer of 3 or greater. The siloxane units in the parentheses to which k and m are attached may be arranged in any order. (A-ii) An organopolysiloxane represented by the following formula (2) and having a number average molecular weight (Mn) of 3,000 to 100,000: A p (R 1 3SiO 1 / 2 ) q (SiO 4 / 2 ) r (2) (In the formula, R 1 has the same meaning as above, A is a siloxane unit represented by the following formula (3), and p, q, and r are numbers that satisfy p>0, q>0, and r>0, respectively, and p+q+r=1. [ka] (In the formula, R 1 , R 2and R 3 has the same meaning as above, n represents an integer of 0 to 10, and c represents an integer of 1 to 3. 3. The photo- and heat-curable silicone composition according to 1, wherein the component (B) is the following (B-iii), (B-iv), or both: (B-iii) A linear organopolysiloxane represented by the following formula (4), having a viscosity at 23°C of 50 to 10,000,000 mPa·s: R 4 R 1 2Si(OSiR 1 2) S OSiR 1 2nd Round 4 (4) (In the formula, R 1 has the same meaning as above, and R 4 represents an alkenyl group having 2 to 20 carbon atoms, and s represents an integer of 1 to 10,000. (B-iv) Organopolysiloxane represented by the following formula (5): (R 1 3SiO 1 / 2 ) t (R 4 R 1 2SiO 1 / 2 ) u (SiO 4 / 2 ) v (5) (In the formula, R 1 and R 4 has the same meaning as above, and t, u, and v are numbers that satisfy t>0, u>0, v>0, and (t+u+v)=1, respectively. 4. The photo- and thermo-curable silicone composition of 1, wherein the component (C) is a linear organohydrogenpolysiloxane represented by the following formula (7): (R 1 3SiO 1 / 2 ) w (H (3-f) R 1 f SiO 1 / 2 ) 2-w (HR 1 1SiO 2 / 2 ) x (R 1 2SiO2 / 2 ) y (7) (In the formula, R 1 has the same meaning as above, f represents 1 or 2, w represents an integer satisfying 0≦w≦2, and x and y represent positive integers satisfying 2≦x+y≦800 and 0.6≦x / (x+y+2)≦1.0. 5. The photo- and thermo-curable silicone composition according to 1, wherein the component (D) is a photoradical polymerization initiator that does not contain nitrogen atoms, sulfur atoms, or phosphorus atoms. 6. (α) A step of irradiating any one of the photo- and thermosetting silicone compositions 1 to 5 with ultraviolet light to partially cure the composition and form a semi-cured composition; and (β) A step of heating the resulting semi-cured composition to completely cure it A method for producing a cured product comprising the steps of: to provide. [Effects of the Invention]

[0011] The photo- and heat-curable silicone composition of the present invention has two curing stages, each of which uses a different method for inducing curing, making it easy to control and handle. Specifically, the first curing stage, which uses light, can be carried out at room temperature in a short time because the polymerization reaction proceeds instantaneously during UV irradiation. Furthermore, the semi-cured composition after the first curing stage is easy to handle and does not change in hardness over a long period of time even in a low-temperature environment such as refrigeration, ensuring ample time before the second curing stage, which uses heat. The photo- and heat-curable silicone composition of the present invention, which has these properties, is particularly useful as an adhesive film, an optical device sealing material, or an adhesive for electronic device components. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be specifically described below. The photo- and thermosetting silicone composition according to the present invention comprises the following components (A) to (E):

[0013] [1] Component (A) Component (A) in the photo- and thermosetting silicone composition of the present invention is an organopolysiloxane having at least three (meth)acrylic groups per molecule, and is preferably the following (Ai), (A-ii), or both: In the present invention, the term "(meth)acrylic group" refers to an acrylic group or a methacrylic group.

[0014] (Ai) Organopolysiloxane represented by the following formula (1):

[0015] [ka] (In the formula, R 1 are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and R 2 each independently represents an oxygen atom or an alkylene group having 1 to 20 carbon atoms; R 3 are each independently an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group; k is an integer of 0 to 1,000; m is an integer of 0 to 20; a and b are each independently an integer of 0 to 3; and a+b+m is an integer of 3 or greater. The siloxane units in the parentheses to which k and m are attached may be arranged in any order.

[0016] (A-ii) An organopolysiloxane represented by the following formula (2) and having a number average molecular weight (Mn) of 3,000 to 100,000: A p (R 1 3SiO 1 / 2 ) q (SiO 4 / 2 ) r (2) (In the formula, R 1 has the same meaning as above, A is a siloxane unit represented by the following formula (3), and p, q, and r are numbers that satisfy p>0, q>0, and r>0, respectively, and p+q+r=1.

[0017] [ka] (In the formula, R 1 , R 2 and R 3 has the same meaning as above, n represents an integer of 0 to 10, and c represents an integer of 1 to 3.

[0018] R 1 The alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, may be linear, branched, or cyclic, and specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-hexyl, cyclohexyl, n-octyl, 2-ethylhexyl, and n-decyl groups. Also, R 1 Specific examples of the aryl group having 6 to 20 carbon atoms, preferably 6 to 10 carbon atoms, include phenyl, tolyl, xylyl, and naphthyl groups. In addition, some or all of the hydrogen atoms bonded to these carbon atoms may be substituted with other substituents, specific examples of which include halogen-substituted hydrocarbon groups such as chloromethyl, bromoethyl, trifluoropropyl, and cyanoethyl groups, and cyano-substituted hydrocarbon groups. Among these, R 1 As the alkyl group, an alkyl group having 1 to 5 carbon atoms and a phenyl group are preferred, and a methyl group, an ethyl group and a phenyl group are more preferred.

[0019] R 2 The alkylene group having 1 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include methylene, ethylene, propylene, trimethylene, tetramethylene, isobutylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, and nonamethylene groups. Among these, R 2 is preferably an oxygen atom, a methylene group, an ethylene group or a trimethylene group, more preferably an oxygen atom or an ethylene group.

[0020] R 3Specific examples of the compound include, but are not limited to, those represented by the following formulas:

[0021] [ka] (In the formula, g represents an integer of 1 to 4.)

[0022] In the above formula (1), a and b are integers of 0 to 3, and the sum with m (a+b+m) is 3 or greater. If a+b+m is less than 3, the curing reaction by light is less likely to occur, and the hardness of the resulting silicone cured product may be insufficient. In particular, it is preferable that a and b are 2 and m is 4. k is an integer from 0 to 1,000, and polymerizability may be poor if k exceeds 1,000. From the standpoints of resistance to volatilization of the component (Ai) and polymerizability, k is preferably an integer from 30 to 500, and more preferably an integer from 50 to 400. m is an integer of 0 to 20, preferably an integer of 0 to 10, and more preferably 0. If m exceeds 20, the composition may become cloudy when cured.

[0023] In the above formula (2), p, q, and r are numbers that satisfy p>0, q>0, and r>0, respectively, and p+q+r=1. From the standpoint of ease of handling the composition and the hardness of the resulting silicone cured product, p is preferably 0.05 to 0.07, q is preferably 0.33 to 0.35, and r is preferably 0.58 to 0.62.

[0024] The number-average molecular weight of component (A-ii) is in the range of 3,000 to 100,000, and preferably in the range of 5,000 to 10,000. If the number-average molecular weight is less than 3,000, the number of (meth)acrylic groups contained in each molecule may fall below 3, which may result in insufficient hardness of the silicone cured product obtained after the two-stage curing. If the number-average molecular weight exceeds 100,000, the compatibility of component (A-ii) may decrease. The number average molecular weight in the present invention is a value calculated as a standard polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a developing solvent.

[0025] The component (A) may be used alone or in combination of two or more. Furthermore, since component (A-ii) may become solid in the environment in which it is used, it may be dissolved in advance in component (Ai) or a liquid organic compound containing a (meth)acrylic group. From the standpoint of ease of handling, the viscosity of component (A) as a whole at 23°C is preferably 100,000 mPa·s or less (typically 1 to 100,000 mPa·s), and more preferably 10,000 mPa·s or less (for example, 5 to 10,000 mPa·s). The viscosity in the present invention is a value measured using a B-type rotational viscometer.

[0026] The amount of (meth)acrylic groups contained in component (A) is within the range of 1 to 15 mmol, preferably 1.5 to 14 mmol, per 100 g of the composition. If it is less than 1 mmol / 100 g, the first-stage curing may be insufficient, while if it exceeds 15 mmol / 100 g, the first-stage curing may result in an excessively high hardness, eliminating the benefit of performing the second-stage curing.

[0027] [2](B) Component Component (B) in the photo- and thermosetting silicone composition of the present invention is an organopolysiloxane having at least two alkenyl groups in one molecule and no (meth)acrylic groups, and is preferably the following (B-iii), (B-iv), or both:

[0028] (B-iii) A linear organopolysiloxane represented by the following formula (4), having a viscosity at 23°C of 50 to 10,000,000 mPa·s: R 4 R 1 2Si(OSiR 1 2) S OSiR 1 2nd Round4 (4) (In the formula, R 1 has the same meaning as above, and R 4 represents an alkenyl group having 2 to 20 carbon atoms, and s represents an integer of 1 to 10,000. (B-iv) Organopolysiloxane represented by the following formula (5): (R 1 3SiO 1 / 2 ) t (R 4 R 1 2SiO 1 / 2 ) u (SiO 4 / 2 ) v (5) (In the formula, R 1 and R 4 has the same meaning as above, and t, u, and v are numbers that satisfy t>0, u>0, and v>0, and (t+u+v)=1, respectively.

[0029] In the above formula (4), R 1 Examples of the group include the same as those of the above formula (1), but a methyl group and a phenyl group are preferred. R 4 The alkenyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include vinyl, allyl, butenyl, pentenyl, hexenyl, and octenyl groups, with the vinyl group being preferred. s is an integer of 1 to 10,000, and preferably an integer of 100 to 1,000.

[0030] The viscosity of the component (B-iii) at 25°C is 50 to 10,000,000 mPa·s, and preferably 100 to 100,000 mPa·s.

[0031] In the above formula (5), R 1 Examples of the group include the same as those of the above formula (1), but a methyl group and a phenyl group are preferred. R 4The alkenyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include vinyl, allyl, butenyl, pentenyl, hexenyl, and octenyl groups, with the vinyl group being preferred. t, u, and v are numbers that satisfy t>0, u>0, and v>0, respectively, and (t+u+v)=1. From the viewpoints of curability and hardness of the cured product, (t+u) / v is preferably 0.3 to 2.0, and more preferably 0.5 to 1.0.

[0032] The number-average molecular weight of component (B-iv) is preferably 500 to 500,000, and more preferably 1,000 to 100,000. If the number-average molecular weight is less than 500, the number of alkenyl groups contained per molecule may fall below 2, which may result in insufficient hardness of the silicone cured product obtained after the two-stage curing. If the number-average molecular weight exceeds 500,000, the compatibility of component (B-iv) may decrease.

[0033] The component (B) may be used alone or in combination of two or more. Furthermore, since component (B-iv) may become solid in the environment in which it is used, it may be dissolved in component (B-iii) before use. From the standpoint of ease of handling, the viscosity of component (B) as a whole at 23°C is preferably 100,000 mPa·s or less (typically 1 to 100,000 mPa·s), and more preferably 10,000 mPa·s or less (for example, 5 to 10,000 mPa·s).

[0034] The amount of component (B) to be blended is an amount such that the ratio of the number of alkenyl groups in the composition to the number of (meth)acrylic groups contained in component (A) is 0.5 or more, preferably 0.5 to 30. If it is less than 0.5, the change in hardness due to the second-stage curing will be minimal, and the benefit of performing two-stage curing may be lost.

[0035] [3](C) component Component (C) is an organohydrogenpolysiloxane having at least two hydrosilyl groups per molecule, and specific examples include those represented by the following average composition formula (6). R 1 d H e SiO (4-d-e) / 2 (6) (In the formula, R 1 has the same meaning as above, d is 0.7 to 2.1, e is 0.001 to 1.0, and is a number that satisfies 0.8≦d+e≦3.0.

[0036] In the above formula (6), d is preferably 1.0 to 1.8, e is preferably 0.1 to 1, and d+e is preferably 1≦d+e≦2.4, more preferably 1.6≦d+e≦2.2. Within these ranges, foaming during curing can be suppressed, the hardness of the resulting cured product is further improved, and changes in hardness over time are less likely to occur.

[0037] In particular, the component (C) is preferably a linear organohydrogenpolysiloxane represented by the following formula (7). (R 1 3SiO 1 / 2 ) w (H (3-f) R 1 f SiO 1 / 2 ) 2-w (HR 1 1SiO 2 / 2 ) x (R 1 2SiO 2 / 2 ) y (7) In equation (7), R 1 Examples of the group include the same as those of the above formula (1), but a methyl group is preferred. f is 1 or 2, with 2 being preferred. w is an integer that satisfies 0≦w≦2, preferably 0 or 2, and more preferably 2. x and y are positive integers that satisfy 2≦x+y≦800 and 0.6≦x / (x+y+2)≦1.0, and preferably positive integers that satisfy 7≦x+y≦700 and 0.7≦x / (x+y+2)≦0.9.

[0038] The kinematic viscosity of component (C) at 23°C is 0.5 to 1,000 mm 2 / s is preferable, and 1 to 100 mm 2 / s is more preferable. Here, the kinematic viscosity is a value measured using a Cannon-Fenske viscometer.

[0039] The component (C) may be used alone or in combination of two or more. The amount of component (C) to be added is such that the ratio of the number of hydrosilyl groups to the number of alkenyl groups and (meth)acrylic groups contained in components (A) and (B) is in the range of 0.8 to 3.0, preferably 0.9 to 2.0. If it is less than 0.8, the curability in the second curing stage and the hardness of the resulting cured product may be insufficient, while if it exceeds 3.0, the hardness of the resulting cured product will change significantly over time.

[0040] [4](D) component ( D Component (D) is a photopolymerization initiator that generates organic radical species by absorbing ultraviolet light, which act as the starting point for the polymerization reaction of the (meth)acrylic group. The photopolymerization initiator of component (D) preferably does not contain nitrogen, sulfur, or phosphorus atoms so as not to inhibit the addition reaction, which is the first-stage curing mechanism. Specific examples of such photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one (Omnirad 651, manufactured by IGM Resins BV), 1-hydroxycyclohexylphenyl ketone (Omnirad 184, manufactured by IGM Resins BV), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Omnirad 1173, manufactured by IGM Resins BV), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropan-1-one (Omnirad 127, manufactured by IGM Resins BV), and phenylglyoxylic acid methyl ester (Omnirad MBF, manufactured by IGM Resins BV). Among these, 2,2-diethoxyacetophenone and 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad 1173, manufactured by IGM Resins BV) are preferred from the viewpoint of compatibility with components (A) and (B).

[0041] The component (D) may be used alone or in combination of two or more. The amount of component (D) added is preferably within a range of 0.01 to 20% by mass relative to the total mass of components (A), (B), and (C), which provides good curability and excellent deep curing properties.

[0042] [5](E) component Component (E) is a hydrosilylation reaction catalyst that promotes the addition reaction between the alkenyl groups in components (A) and (B) and the Si—H groups in component (C). Specific examples include carbon powder carrying platinum metal, platinum black, platinic chloride, chloroplatinic acid, reaction products of chloroplatinic acid and monohydric alcohols, complexes of platinum and vinylsiloxanes such as divinyltetramethyldisiloxane, complexes of chloroplatinic acid and olefins, platinum-based catalysts such as platinum bisacetoacetate, palladium-based catalysts, rhodium-based catalysts and other platinum group metal catalysts, and the like. Of these, those containing platinum are preferred from the standpoint of reactivity, and complexes of platinum and vinylsiloxanes are more preferred.

[0043] There are no particular restrictions on the amount of component (E) that may be added, provided that it is an amount that promotes the hydrosilylation reaction. However, the amount is preferably in the range of 0.01 to 500 ppm, more preferably 0.05 to 100 ppm, and even more preferably 0.01 to 50 ppm, calculated as the mass of the metal in component (E) relative to the total of components (A), (B), and (C).

[0044] [6] Other ingredients In addition to the above-mentioned components (A) to (E), the photo- and heat-curable silicone composition of the present invention may contain other components as long as the object of the present invention is not impaired. Other components include, for example, reaction control agents such as 3-methyl-1-butyn-3-ol and ethynylmethyldecylcarbinol that control the reactivity of the platinum catalyst; adhesion aids having adhesion-imparting groups such as carbonyl groups, epoxy groups, and alkoxysilyl groups; thixotropy control agents such as fumed silica; reinforcing agents such as crystalline silica; antioxidants; light stabilizers; heat resistance improvers such as metal oxides and metal hydroxides; pigments such as titanium oxide; dyes; thermal conductivity-imparting fillers such as alumina; viscosity adjusters such as non-reactive silicone oils that do not have reactive functional groups; and conductivity-imparting agents such as metal powders of silver, gold, etc.

[0045] The photo- and heat-curable silicone composition of the present invention can be prepared by mixing the above components (A) to (E) and other components used as needed using a known method. In this case, the composition of the present invention may be prepared as a one-part type, or may be prepared as a two-part type or as three or more parts which are each prepared separately and mixed in any ratio when used.

[0046] The method for producing a cured product of the photo- and thermosetting silicone composition of the present invention comprises the steps of: (α) irradiating the photo- and thermosetting silicone composition with ultraviolet light to partially cure the composition into a semi-cured composition; and (β) A step of heating the resulting semi-cured composition to completely cure it.

[0047] The ultraviolet light irradiated in step (α) preferably has a wavelength of 200 to 500 nm, more preferably 200 to 350 nm. From the viewpoint of preventing discoloration, the irradiation temperature is preferably 20 to 40°C, and the irradiation intensity is preferably 30 to 2,000 mW / cm. 2 More preferably, the irradiation dose is 150 to 100,000 mJ / cm 2 is preferred. As a light source of ultraviolet light, a 365 nm UV-LED lamp, a metal halide lamp, a high-pressure mercury lamp, etc. can be used, and as a method of ultraviolet light irradiation, a method of irradiating an appropriate amount of ultraviolet light onto the composition can be mentioned, but when performing on a transparent substrate such as glass or a resin film, ultraviolet light may be irradiated through the glass or film. When irradiating with ultraviolet light, it is preferable to do so in a nitrogen or argon atmosphere to suppress the influence of oxygen, which inhibits curing. The heating conditions in step (β) are preferably 50 to 150°C, more preferably 80 to 120°C, for 10 minutes to 1 day, more preferably 30 minutes to 1 hour. [Example]

[0048] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following, viscosity at 23°C was measured using a Brookfield rotational viscometer, and kinematic viscosity at 23°C was measured using a Cannon-Fenske viscometer. Vi represents a vinyl group, and Me represents a methyl group.

[0049] [1] Preparation of photo- and heat-curable silicone compositions [Examples 1-1 to 1-7, Comparative Examples 1-1 to 1-6] Components (A) to (E) shown below and other components were mixed in the amounts (parts by mass) shown in Tables 1 and 2 to prepare photo- and thermosetting silicone compositions.

[0050] Component (A) (Ai-1): Organopolysiloxane represented by the following formula (8) (viscosity at 23°C: 3,000 mPa·s, acrylic group content: 0.02 mol / 100 g) [ka] (In the formula, the arrangement of each siloxane unit in parentheses is random or block.)

[0051] (Ai-2): Organopolysiloxane represented by the following formula (9) (viscosity at 23°C: 1,000 mPa·s, acrylic group content: 0.026 mol / 100 g) [ka]

[0052] (A-ii-1): Siloxane unit represented by the following formula (10) / (ViMeSiO 1 / 2 Unit) / (Me3SiO 1 / 2 Organopolysiloxane with a molar ratio of (SiO2 units) / (SiO2 units) of 0.056 / 0.014 / 0.390 / 0.540 (number average molecular weight 5,700, average number of methacrylic groups per molecule 3.7, amount of methacrylic groups 0.0656 mol / 100g, amount of vinyl groups 0.0164 mol / 100g) [ka]

[0053] (B) Component (B-iii-1): Organopolysiloxane represented by the following formula (11) (viscosity at 23°C: 3,000 mPa·s, vinyl group content: 0.01 mol / 100 g) [ka] (In the formula, the arrangement of each siloxane unit in parentheses is random or block.)

[0054] (B-iii-2): Organopolysiloxane represented by the following formula (12) (viscosity at 23°C: 1,600 mPa s, vinyl group content: 0.013 mol / 100 g) [ka]

[0055] (B-iii-3): Organopolysiloxane represented by the following formula (13) (viscosity at 23°C: 5,000 mPa s, vinyl group content: 0.006 mol / 100 g) [ka]

[0056] (B-iv-1): Organopolysiloxane represented by the following average formula (14) (number average molecular weight: 4,500, average number of vinyl groups per molecule: 3.7, vinyl group amount: 0.082 mol / 100 g) (ViMe2SiO 1 / 2 ) 0.058 (MeSiO 1 / 2 ) 0.402 (SiO 4 / 2 ) 0.540 (14)

[0057] (C) Component (C-1): Organohydrogenpolysiloxane represented by the following formula (15) (kinematic viscosity at 23°C: 4.5 mm 2 / s, silicon-bonded hydrogen atom content = 0.0145 mol / g)

[0058] [ka] (In the formula, the arrangement of each siloxane unit in parentheses is random or block.)

[0059] (D) Component (D-1): 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad 1173, manufactured by IGM Resins BV)

[0060] (E) Component (E-1) Toluene solution of platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (platinum content 0.5% by mass)

[0061] (Other ingredients) Reaction control agent: ethynylmethyldecylcarbinol Diluent: a disiloxane compound represented by the following structural formula (16) [ka]

[0062] [Table 1]

[0063] [Table 2]

[0064] [2] Production of cured products of photo- and heat-curable silicone compositions [Examples 2-1 to 2-7, Comparative Examples 2-1 to 2-6] The photo- and heat-curable silicone compositions obtained in Examples 1-1 to 1-7 and Comparative Examples 1-1 to 1-6 were irradiated in a nitrogen environment with a UV-LED lamp having a wavelength of 365 nm at 25°C with an irradiation intensity of 100 mW / cm. 2 and a dose of 3,000 mJ / cm 2The first stage of curing was carried out by irradiating with ultraviolet light so that the cured product reached a value of 0.015. The penetration or durometer A hardness of the resulting cured product was measured using a penetrometer (1 / 4 cone) or durometer A hardness meter manufactured by Rigo Co., Ltd. in accordance with JIS K 6249. When the penetration was less than 1 and measurement was impossible, durometer A hardness was used. The cured product obtained in the first stage curing was then left to stand at 120°C for 1 hour to perform the second stage curing. The cured product obtained was cooled to 25°C and then subjected to the same hardness measurement as for the first stage cured product. The results are shown in Tables 3 and 4.

[0065] [Table 3]

[0066] [Table 4]

[0067] As shown in Tables 3 and 4, the photo- and heat-curable silicone compositions prepared in Examples 1-1 to 1-7 show a large difference in hardness between the first-stage curing by light and the second-stage curing by heat. On the other hand, when the compositions of Comparative Examples 1-1, 1-5, and 1-6, in which the amount of (meth)acrylic groups in component (A) was less than 1 mmol per 100 g of the composition, were used, the first-stage curing by light did not occur. When the compositions of Comparative Examples 1-2 to 1-4, in which the amount of (meth)acrylic groups in component (A) was more than 15 mmol per 100 g of the composition, were used, the first-stage curing by light proceeded too much, resulting in almost no difference in hardness with the second-stage curing, and the material did not become a two-stage curing material.

Claims

1. (A) an organopolysiloxane having at least three (meth)acrylic groups in one molecule; (B) an organopolysiloxane having at least two alkenyl groups in one molecule and no (meth)acrylic group; (C) an organohydrogenpolysiloxane having at least two hydrosilyl groups in one molecule; (D) a photopolymerization initiator, and (E) Hydrosilylation reaction catalyst Contains the amount of (meth)acrylic groups contained in the component (A) is 1.5 to 14 mmol per 100 g of the composition; the ratio of the number of alkenyl groups in the composition to the number of (meth)acrylic groups contained in component (A) is 0.5 or more, A photo- and heat-curable silicone composition in which the ratio of the number of hydrosilyl groups to the number of alkenyl groups and (meth)acrylic groups contained in components (A) and (B) is 0.8 to 3.

0.

2. 2. The photo- and thermo-curable silicone composition according to claim 1, wherein the component (A) is the following (Ai), (A-ii), or both: (Ai) Organopolysiloxane represented by the following formula (1): 【Chemistry 1】 (In the formula, R 1 are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms; R 2 each independently represents an oxygen atom or an alkylene group having 1 to 20 carbon atoms; R 3 are each independently an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group; k is an integer from 0 to 1,000; m is an integer from 0 to 20; a and b are each independently an integer from 0 to 3; and a+b+m is an integer of 3 or greater. The siloxane units in the parentheses to which k and m are attached may be arranged in any order. (A-ii) An organopolysiloxane represented by the following formula (2) and having a number average molecular weight (Mn) of 3,000 to 100,000: A p (R 1 3 SiO 1 / 2 ) q (SiO 4 / 2 ) r (2) (In the formula, R 1 represents the same meaning as above, A is a siloxane unit represented by the following formula (3), and p, q, and r are numbers that satisfy p>0, q>0, and r>0, and p+q+r=1, respectively. 【Chemistry 2】 (In the formula, R 1 , R 2 and R 3 represents the same meaning as above, n represents an integer of 0 to 10, and c represents an integer of 1 to 3.

3. 2. The photo- and thermosetting silicone composition according to claim 1, wherein the component (B) is the following (B-iii), (B-iv), or both: (B-iii) A linear organopolysiloxane represented by the following formula (4), having a viscosity at 23°C of 50 to 10,000,000 mPa·s: R 4 R 1 2 Si(OSiR 1 2 ) S OSiR 1 2 R 4 (4) (In the formula, R 1 has the same meaning as above, and R 4 represents an alkenyl group having 2 to 20 carbon atoms, and s represents an integer of 1 to 10,000. (B-iv) Organopolysiloxane represented by the following formula (5): (R 1 3 SiO 1 / 2 ) t (R 4 R 1 2 SiO 1 / 2 ) u (SiO 4 / 2 ) v (5) (In the formula, R 1 and R 4 has the same meaning as above, and t, u, and v are numbers that satisfy t>0, u>0, v>0, and (t+u+v)=1.

4. 2. The photo- and heat-curable silicone composition according to claim 1, wherein component (C) is a linear organohydrogenpolysiloxane represented by the following formula (7): (R 1 3 Yes 1 / 2 ) w (H (3-f) R 1 f Yes 1 / 2 ) 2-w (HR) 1 1 Yes 2 / 2 ) x (R 1 2 Yes 2 / 2 ) y (7) (In the formula, R 1 represents the same meaning as above, f represents 1 or 2, w represents an integer satisfying 0≦w≦2, and x and y represent positive integers satisfying 2≦x+y≦800 and 0.6≦x / (x+y+2)≦1.

0.

5. 2. The photo- and thermo-curable silicone composition according to claim 1, wherein component (D) is a photoradical polymerization initiator that does not contain nitrogen, sulfur, or phosphorus atoms.

6. (α) irradiating the photo- and thermosetting silicone composition according to any one of claims 1 to 5 with ultraviolet light to partially cure the composition into a semi-cured composition; and (β) A step of heating the obtained semi-cured composition to completely cure it. A method for producing a cured product comprising the steps of:

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