Radical curable silicone composition and silicone cured product

Abstract

To provide a radical curable silicone composition that can be cured at low temperatures to yield a cured product of high hardness.SOLUTION: A radical curable silicone composition contains: (A) a three dimensional network-like organopolysiloxane, represented by the following formula (1); (B) a straight-chain organopolysiloxane having a phenyl group bonded to a silicon atom and a substituent group having a radical polymerizable functional group; (C) a polymerization initiator; and (D) a solvent. The formula (1): (R13SiO1 / 2)m1(R2R12SiO1 / 2)m2(R3R12SiO1 / 2)m3(SiO4 / 2)q (where R1's independently denote a 1-12C monovalent hydrocarbon group having no aliphatic unsaturated bond; R2 denotes a 2-8C alkenyl group; and R3 denotes a substituent group having a radical polymerizable functional group. m1≥0, m2≥0, m3>0, and q>0, and m1+m2+m3+q=1 is satisfied).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a radically curable silicone composition and a cured product thereof. [Background technology]

[0002] Due to the remarkable improvement in light-emitting efficiency, light-emitting diode (LED) lights are characterized by low power consumption, long life, and design, and the market is expanding rapidly not only for liquid crystal display (LCD) backlights and in-vehicle fields such as car headlights, but also for general lighting. Such LED lights are configured by sealing an LED chip mounted on a substrate with a sealing material made of transparent resin. Addition-curing silicone compositions are widely used as sealing materials for sealing LEDs because of their excellent heat resistance.

[0003] Since the emission spectrum of an LED depends on the semiconductor material that forms the LED chip, in order to obtain white light for LCD backlighting or general lighting, it is necessary to place a phosphor that is compatible with each LED chip on the chip and convert the emission wavelength. Specifically, methods have been proposed, such as placing a yellow phosphor on a blue-emitting LED chip, placing red and green phosphors on a blue-emitting LED chip, and placing red, green, and blue phosphors on an ultraviolet-emitting LED chip. Among these, the method of placing a yellow phosphor on a blue LED and the method of placing red and green phosphors on a blue LED are currently most widely adopted in terms of the luminous efficiency and cost of the LED chip.

[0004] As one of the specific methods for placing a phosphor on an LED chip, a method has been proposed in which a phosphor is dispersed in a silicone composition containing an alkenyl group-containing organopolysiloxane and a hydrogen organopolysiloxane, and a sheet cured by a hydrosilylation reaction using a platinum group metal catalyst is attached (Patent Documents 1 to 5). However, when such an addition-curing silicone resin is used as a phosphor binder, curing may be inhibited by a catalyst poison contained in the phosphor. In addition, since high temperature heating is required to cure such an addition-curing silicone composition, it is difficult to use a phosphor with low heat resistance.

[0005] Previously, the present inventors have proposed a radical-curing silicone composition that is not affected by catalyst poisons and can be cured at low temperatures (Patent Document 6). However, the sheet formed from this composition has low hardness, and there are problems such as insufficient strength and the sheet stretching during handling. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-1791 A [Patent Document 2] JP 2013-1792 A [Patent Document 3] JP 2013-138216 A [Patent Document 4] JP 2014-114446 A [Patent Document 5] JP 2014-116598 A [Patent Document 6] Patent Publication No. 2021-1296 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide a radical-curable silicone composition that can be cured at low temperatures and gives a cured product with high hardness. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides (A) a three-dimensional network organopolysiloxane represented by the following formula (1): (R 1 3SiO 1 / 2 ) m1 (R 2 R 1 2SiO 1 / 2 ) m2 (R 3 R 1 2SiO 1 / 2 ) m3 (SiO 4 / 2 ) q (1) (In the formula, R 1 are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and having no aliphatic unsaturated bonds; R 2 is an alkenyl group having 2 to 8 carbon atoms, R 3 is a substituent having a radically polymerizable functional group. m1, m2, m3, and q are numbers that satisfy m1≧0, m2≧0, m3>0, and q>0, and that satisfy m1+m2+m3+q=1. (B) a linear organopolysiloxane having a phenyl group bonded to a silicon atom and a substituent having a radically polymerizable functional group; (C) a polymerization initiator, and (D) Solvent The present invention provides a radical-curable silicone composition comprising:

[0009] The radically curable silicone composition of the present invention can be cured at low temperatures by radical curing, and can give a cured product with high hardness.

[0010] In the radically curable silicone composition of the present invention, the component (B) is preferably a linear organopolysiloxane represented by the following formula (3). (R 2 R 1 2SiO 1 / 2 ) m4 (R 3 R 1 2SiO 1 / 2 ) m5 (R 1 2SiO 2 / 2 ) d1 (R 1 R 2 SiO 2 / 2 ) d2 (R 1 R 3 SiO 2 / 2 ) d3 (3) (In the formula, R 1 , R 2 and R 3 has the same meaning as above, except that all R 1 are phenyl groups, and m4, m5, d1, d2, and d3 are numbers that satisfy m4≧0, m5≧0, d1≧0, d2≧0, and d3≧0, respectively, and m4+m5>0, m5+d3>0, and m4+m5+d1+d2+d3=1.

[0011] Such a radically curable silicone composition has excellent compatibility and transparency.

[0012] The radical curable silicone composition of the present invention is 3 is preferably a group represented by the following formula (2). [ka] (In the formula, R 1 has the same meaning as above, and R 4 are each independently a substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms, R 5 is a hydrogen atom or a methyl group, and * represents a bond to an adjacent silicon atom.

[0013] If the substituent has such a radically polymerizable functional group, the composition of the present invention will have better curability.

[0014] In the radically curable silicone composition of the present invention, the polymerization initiator is preferably an organic peroxide.

[0015] Such a polymerization initiator can more effectively cure the composition of the present invention.

[0016] In this case, it is more preferable that the organic peroxide has a 10-hour half-life temperature of 50 to 150°C.

[0017] Such an organic peroxide provides a composition with excellent storage stability and controllability of curing properties, and can be cured at low temperatures, thereby suppressing the thermal effects on the phosphor.

[0018] The present invention also provides a silicone cured product, which is a cured product of the above radically curable silicone composition.

[0019] The silicone cured product of the present invention has good hardness and is therefore useful as a wavelength converting material, such as a sheet with a dispersed phosphor or an encapsulant. Effect of the Invention

[0020] The radically curable silicone composition of the present invention can be cured at low temperatures by radical curing, and a cured product with high hardness can be obtained, making it useful for applications as a wavelength converting material such as a phosphor sheet or an encapsulant. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] As a result of intensive research into achieving the above object, the present inventors discovered that the above problems could be solved by a radical-curable silicone composition containing components (A) to (D) described below, and thus completed the present invention.

[0022] That is, the present invention relates to (A) a three-dimensional network organopolysiloxane represented by the following formula (1): (R 1 3SiO 1 / 2 ) m1 (R 2 R 1 2SiO 1 / 2 ) m2 (R 3 R 1 2SiO 1 / 2 ) m3 (SiO 4 / 2 ) q (1) (In the formula, R 1 are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and having no aliphatic unsaturated bonds; R 2 is an alkenyl group having 2 to 8 carbon atoms, R 3 is a substituent having a radically polymerizable functional group. m1, m2, m3, and q are numbers that satisfy m1≧0, m2≧0, m3>0, and q>0, and that satisfy m1+m2+m3+q=1. (B) a linear organopolysiloxane having a phenyl group bonded to a silicon atom and a substituent having a radically polymerizable functional group; (C) a polymerization initiator, and (D) Solvent The radical curable silicone composition is characterized by comprising:

[0023] The present invention will be described in detail below, but the present invention is not limited thereto.

[0024] [Radical curing type silicone composition] The radically curable silicone composition of the present invention contains the following components (A) to (D) as essential components. This composition can further contain optional components as necessary in addition to the essential components. Each component will be described in detail below.

[0025] [Component (A)] Component (A) is a three-dimensional network organopolysiloxane represented by the following formula (1) and has the following ratio of constituent units: (R 1 3SiO 1 / 2 ) m1 (R 2 R 1 2SiO 1 / 2 ) m2 (R 3 R 1 2SiO 1 / 2 ) m3 (SiO 4 / 2 ) q (1) (In the formula, R 1 are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and containing no aliphatic unsaturated bonds; R 2 is an alkenyl group having 2 to 8 carbon atoms, R 3 is a substituent having a radical polymerizable functional group. m1, m2, m3, and q are numbers that satisfy m1≧0, m2≧0, m3>0, and q>0, and that satisfy m1+m2+m3+q=1.

[0026] The three-dimensional network organopolysiloxane represented by the above formula (1) is 1 3SiO 1 / 2 ) unit (also called "m1 unit"; the same applies below), (R 2 R 1 2SiO 1 / 2 ) units (m2 units), (R 3 R 1 2SiO 1 / 2 ) units (m3 units), (SiO 4 / 2 ) units (q units), and the constituent ratios m1, m2, m3, and q of each unit are numbers that satisfy m1≧0, m2≧0, m3>0, and q>0, respectively, and that satisfy m1+m2+m3+q=1. The three-dimensional network organopolysiloxane contains m3 units and q units as essential units, and R 3 The component (A) has a radical polymerizable R 3 The presence of these groups enables radical curing at low temperatures, and the hardness of the cured product is improved by radical crosslinking. The above m1, m2, and m3 units may each be composed of a combination of two or more different siloxane units (small units), and the arrangement order of the small units in each of the above units is arbitrary (undefined).

[0027] In the above formula (1), R 1 Examples of the substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and no aliphatic unsaturated bond, represented by the formula (I), include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; aryl groups such as phenyl and naphthyl; aralkyl groups such as benzyl and phenethyl; and halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl, with a methyl group being particularly preferred.

[0028] R 2 Examples of the alkenyl group having 2 to 8 carbon atoms represented by the formula (I) include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and an octenyl group, with a vinyl group being particularly preferred.

[0029] R 3 is a substituent having a radically polymerizable functional group, and is not particularly limited, but is preferably a substituent having a methacryl group or an acrylic group, and is particularly preferably one represented by the following formula (2). [ka] (In the formula, R 1 has the same meaning as above, and R 4 are each independently a substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms, R 5 is a hydrogen atom or a methyl group, and * represents a bond to an adjacent silicon atom.

[0030] R 4The substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms represented by the formula (I) is a linear, branched or cyclic alkylene group having 1 to 8 carbon atoms, such as a methylene group, an ethylene group, a propylene group, a trimethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group or an octamethylene group, preferably one having 1 to 4 carbon atoms, and particularly preferably a methylene group, an ethylene group, a propylene group or a trimethylene group. The hydrogen atom in these groups may be further substituted with any substituent (such as a halogen atom).

[0031] From the viewpoints of the handleability of the composition and the hardness of the cured product, it is preferable that m1+m2+m3 be in the range of 0.2≦m1+m2+m3≦0.6. In order to ensure that the hardness of the cured product falls within a more appropriate range, m3 is preferably in the range of 0.01≦m3≦0.05, and more preferably in the range of 0.01≦m3≦0.03.

[0032] Specific examples of the component (A) include those having a structural unit ratio represented by the following formula:

[0033] ((CH3)3SiO 1 / 2 ) 0.40 ((CH2=CH)(CH3)2SiO 1 / 2 ) 0.04 ((R 3 )(CH3)2SiO 1 / 2 ) 0.01 (SiO2) 0.55 ((CH3)3SiO 1 / 2 ) 0.40 ((CH2=CH)(CH3)2SiO 1 / 2 ) 0.03 ((R 3 )(CH3)2SiO 1 / 2 ) 0.02 (SiO2) 0.55 [ka] (In the formula, * represents a bond to an adjacent silicon atom.)

[0034] From the viewpoints of ease of handling of the composition and hardness of the cured product, the weight average molecular weight of the component (A) is preferably 1000 to 20000, and more preferably 2000 to 10000. The weight average molecular weight can be determined, for example, as a polystyrene-equivalent value by gel permeation chromatography (GPC) analysis using toluene as a developing solvent.

[0035] The component (A) may use one type alone, or two or more types in combination.

[0036] [(B) Component] (B) A linear organopolysiloxane having a phenyl group bonded to a silicon atom and a substituent having a radically polymerizable functional group.

[0037] The component (B) is preferably a linear organopolysiloxane represented by the following formula (3), in which the ratio of constituent units is as follows: (R 2 R 1 2SiO 1 / 2 ) m4 (R 3 R 1 2SiO 1 / 2 ) m5 (R 1 2SiO 2 / 2 ) d1 (R 1 R 2 SiO 2 / 2 ) d2 (R 1 R 3 SiO 2 / 2 ) d3 (3) (In the formula, R 1 , R 2 and R 3 has the same meaning as above, except that all R 1 are phenyl groups, and m4, m5, d1, d2, and d3 are numbers that satisfy m4≧0, m5≧0, d1≧0, d2≧0, and d3≧0, respectively, and m4+m5>0, m5+d3>0, and m4+m5+d1+d2+d3=1.

[0038] The linear organopolysiloxane represented by the above formula (3) is 2 R 1 2SiO 1 / 2 ) unit (also called "m4 unit"; the same applies below), (R 3 R 1 2SiO 1 / 2 ) units (m5 units), (R 1 2SiO 2 / 2 ) units (d1 units), (R 1 R 2 SiO 2 / 2 ) units (d2 units), (R 1 R 3 SiO 2 / 2 ) units (d3 units), and the constituent ratios m4, m5, d1, d2, and d3 of each unit are m4≧0, m5≧0, d1≧0, d2≧0, and d3≧0, respectively, and are numbers that satisfy m4+m5>0, m5+d3>0, and m4+m5+d1+d2+d3=1. The linear organopolysiloxane contains either m5 units or d3 units, and R 3 The component (B) has radically polymerizable R groups at either the molecular chain terminals or non-terminal portions of the molecular chain, or at both. 3 The presence of the group allows for radical curing at low temperatures. The above m4, m5, d1, d2, and d3 units may each be composed of a combination of two or more different siloxane units (small units), and the arrangement order of the small units in each of the above units is arbitrary (undefined).

[0039] Here, R 1 are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms that does not have an aliphatic unsaturated bond. Examples of such monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; aryl groups such as phenyl and naphthyl; aralkyl groups such as benzyl and phenethyl; and halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl. Of these, methyl and phenyl are particularly preferred.

[0040] From the viewpoint of compatibility of the composition and transparency of the cured product, the total R 1 At least 1 mol % of the groups are phenyl groups, and preferably 2 to 50 mol %.

[0041] Here, R 2 is an alkenyl group having 2 to 8 carbon atoms. Examples of such an alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and an octenyl group, with a vinyl group being particularly preferred.

[0042] Here, R 3 is a substituent having a radically polymerizable functional group, and is not particularly limited, but is preferably a substituent having a methacryl group or an acrylic group, and is particularly preferably represented by the above formula (2).

[0043] In the above formula (3), m4 is preferably 0 and d2 is preferably 0. In other words, the linear organopolysiloxane represented by formula (3) contains an alkenyl group R 2 It is preferable that the d1 unit does not contain the following. The d1 unit may be composed of a combination of two or more different D units (small units). Examples of such D units include ((CH3)2SiO 2 / 2 ), ((C6H5)2SiO 2 / 2 ), ((C6H5)(CH3)SiO 2 / 2 ) is a combination of two or more D units selected from ((CH3)2SiO 2 / 2 ) and ((C6H5)2SiO 2 / 2 The arrangement order of the subunits in each of the above units is arbitrary.

[0044] Suitable examples of component (B) are shown below, but are not limited to these. In the formulae, Me represents a methyl group, and Ph represents a phenyl group (the same applies below). [ka] (In the formula, the arrangement of the siloxane units in the parentheses is arbitrary, and * represents a bond to an adjacent silicon atom.) [ka] (In the formula, the arrangement of the siloxane units in the parentheses is arbitrary.) [ka] (In the formula, the arrangement of the siloxane units in the parentheses is arbitrary.)

[0045] The amount of the linear organopolysiloxane (B) added is preferably 10 to 1000 parts by mass, and more preferably 20 to 200 parts by mass, per 100 parts by mass of the above (A). Within this range, the hardness of the cured product can be set to a more appropriate range.

[0046] [(C) component] The component (C) is a polymerization initiator that polymerizes the polymerizable functional groups of the components (A) and (B). As the component (C), an organic peroxide that generates radicals by heat can be used.

[0047] As the organic peroxide, from the viewpoint of controlling the storage stability and curability of the composition, an organic peroxide having a 10-hour half-life temperature of 50 to 150°C is preferred, and an organic peroxide having a 10-hour half-life temperature of 60 to 110°C is more preferred.

[0048] Specific examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, o-methylbenzoyl peroxide, p-methylbenzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-ditetrabutylperoxy-cyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne, 1,6-bis(p-toluoylperoxycarbonyloxy)hexane, di(4-methylbenzoylperoxy)hexamethylene biscarbonate, 2,5-dimethoxy-2,5-di(2-ethylhexanoylperoxy)hexane, and 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane.

[0049] Additionally, organic peroxides are commercially available, for example from NOF Corporation. Specifically, Perbutyl NHP (50.6), Perhexyl PV (53.2), Perbutyl PV (54.6), Peroyl 355 (59.4), Peroyl L (61.6), Perocta O (65.3), Peroyl SA (65.9), Perhexa 25 O (66.2), Perhexyl O (69.9), Niper PMB (70.6), Perbutyl O (72.1), Niper BMT (73.1), Niper BW (73.6), Perhexa MC (83.2), Perhexa TMH (86.7), Perhexa HC (87.1), Perhexa C (90.7), Pertetra A (94.7), Perhexyl I (95.0), Perbutyl MA (96 .1), Perbutyl 355 (97.1), Perbutyl L (98.3), Perbutyl I (98.7), Perbutyl E (99.0), Perhexyl Z (99.4), Perhexa 25Z (99.7), Perbutyl A (101.9), Perhexa 22 (103.1), Perbutyl Z (104.3), Perhexa V (104.5), Perbutyl P (119.2), Percumyl D (116.4), Perhexyl D (116.4), Perhexa 25B (117.9), Perbutyl C (119.5), Perbutyl D (123.7), Permenta H (128.0), Perhexine 25B (128.4), Percumyl P (145.1), etc. The numbers in parentheses following the compound names above indicate their respective 10-hour half-life temperatures (unit: °C).

[0050] Of the above organic peroxides, from the viewpoints of compatibility with component (A) and the 10-hour half-life temperature, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane (manufactured by NOF Corporation, Perhexa (registered trademark) 25O, 10-hour half-life temperature 66.2°C) is preferred.

[0051] These organic peroxides can be used alone or in combination of two or more.

[0052] The organic peroxide may be added in an effective amount, usually from 0.01 to 10 parts by mass, and more preferably from 0.1 to 5 parts by mass, per 100 parts by mass of component (A).

[0053] [(D) component] The component (D) is an organic solvent, and is not particularly limited as long as it can dissolve or disperse the above components (A) to (C) and the optional components described below, and known organic solvents can be used. Examples of organic solvents include aromatic hydrocarbon solvents such as xylene, toluene, and benzene, aliphatic hydrocarbon solvents such as heptane and hexane, halogenated hydrocarbon solvents such as trichloroethylene, perchloroethylene, and methylene chloride, ester solvents such as ethyl acetate, ketone solvents such as methyl isobutyl ketone and methyl ethyl ketone, alcohol solvents such as ethanol, isopropanol, and butanol, ligroin, cyclohexanone, diethyl ether, rubber volatile oil, and silicone solvents. Among them, toluene, heptane, and ethyl acetate are preferably used.

[0054] The component (D) may be used alone or in combination as a mixed solvent of two or more types, depending on the evaporation rate during application of the composition.

[0055] The radically curable silicone composition of the present invention may further contain the following optional components, in addition to the above-mentioned components (A) to (D), as necessary.

[0056] [Phosphor] The radical curing silicone composition of the present invention can be used as a wavelength conversion member such as a phosphor sheet by adding a phosphor. The phosphor absorbs blue light, purple light, or ultraviolet light emitted from an LED chip, converts the wavelength, and emits light of a different wavelength from the light of the LED chip, which has a wavelength in the red, orange, yellow, green, or blue region. As a result, a part of the light emitted from the LED chip and a part of the light emitted from the phosphor are mixed to obtain a multi-color LED including white.

[0057] The above-mentioned phosphors include various phosphors such as green-emitting phosphors, blue-emitting phosphors, yellow-emitting phosphors, and red-emitting phosphors. Specific phosphors used in the present invention include known phosphors such as organic phosphors, inorganic phosphors, fluorescent pigments, and fluorescent dyes. Examples of organic phosphors include allylsulfamide-melamine formaldehyde co-condensation dyes and perylene-based phosphors, and perylene-based phosphors are preferably used because they can be used for a long period of time. Examples of phosphors that are particularly preferably used in the present invention include inorganic phosphors. The inorganic phosphors used in the present invention are described below.

[0058] Examples of phosphors that emit green light include SrAl2O4:Eu, Y2SiO5:Ce,Tb, and MgAl 11 O 19 : Ce, Tb, Sr7Al 12 O 25 :Eu, (at least one of Mg, Ca, Sr, Ba) Ga2S4:Eu, etc.

[0059] Examples of phosphors that emit blue light include Sr5(PO4)3Cl:Eu, (SrCaBa)5(PO4)3Cl:Eu, (BaCa)5(PO4)3Cl:Eu, (at least one of Mg, Ca, Sr, Ba)2B5O9Cl:Eu,Mn, (at least one of Mg, Ca, Sr, Ba)(PO4)6Cl2:Eu,Mn, etc.

[0060] Phosphors that emit green to yellow light include yttrium-aluminum oxide phosphors activated with at least cerium, yttrium-gadolinium-aluminum oxide phosphors activated with at least cerium, yttrium-aluminum-garnet oxide phosphors activated with at least cerium, and yttrium-gallium-aluminum oxide phosphors activated with at least cerium (so-called YAG phosphors). 12 : R (Ln is at least one selected from Y, Gd, and La. M includes at least one of Al and Ca. R is a lanthanide.), (Y1-x Ga x )3(Al 1-y Ga y )5O 12 :R (R is at least one or more selected from Ce, Tb, Pr, Sm, Eu, Dy, Ho. 0 < Rx < 0.5, 0 < y < 0.5.) can be used.

[0061] Examples of the phosphor that emits red light include Y2O2S:Eu, La2O2S:Eu, Y2O3:Eu, Gd2O2S:Eu, etc.

[0062] In addition, examples of the phosphor that emits light corresponding to a blue LED include Y3(Al,Ga)5O 12 :Ce, (Y,Gd)3Al5O 12 :Ce, Lu3Al5O 12 :Ce, Y3Al5O 12 :Ce and other YAG-based phosphors, Tb3Al5O 12 :Ce and other TAG-based phosphors, (Ba,Sr)2SiO4:Eu-based phosphors, Ca3Sc2Si3O 12 :Ce-based phosphors, silicate-based phosphors such as (Sr,Ba,Mg)2SiO4:Eu, nitride-based phosphors such as (Ca,Sr)2Si5N8:Eu, (Ca,Sr)AlSiN3:Eu, CaSiAlN3:Eu, etc., Cax(Si,Al) 12 (O,N) 16 :Eu and other oxynitride-based phosphors, furthermore, (Ba,Sr,Ca)Si2O2N2:Eu-based phosphors, Ca8MgSi4O 16 Cl2:Eu-based phosphors, SrAl2O4:Eu, Sr4Al 14 O 25 :Eu and other phosphors can be mentioned.

[0063] Among these, YAG-based phosphors, TAG-based phosphors, and silicate-based phosphors are preferably used in terms of luminous efficiency, luminance, etc.

[0064] In addition to the above, known phosphors can be used according to the application and the target emission color.

[0065] The particle size of the phosphor is not particularly limited, but D50 is preferably 0.05 μm or more, more preferably 3 μm or more. Also, D50 is preferably 30 μm or less, more preferably 20 μm or less. Here, D50 refers to the particle diameter when the cumulative amount of particles passing through from the small particle size side is 50% in the volume-based particle size distribution obtained by measuring using a laser diffraction scattering type particle size distribution measuring method. When D50 is within the above range, the dispersibility of the phosphor in the phosphor sheet is good, and stable light emission is obtained.

[0066] In the present invention, the content of the phosphor is preferably 20 to 500 parts by mass, more preferably 50 to 400 parts by mass or more, and even more preferably 80 to 300 parts by mass, per 100 parts by mass of the solid content of the radical curing silicone composition. By setting the phosphor content in the phosphor sheet within the above range, the light conversion efficiency of the phosphor sheet can be improved. The phosphor sheet of the present invention is particularly preferably used for surface coating of LEDs. In this case, by setting the phosphor content in the phosphor sheet within the above range, an LED light emitting device exhibiting excellent performance can be obtained.

[0067] [Quantum dots] The radical curable silicone composition of the present invention may contain quantum dots that act as wavelength conversion materials. Quantum dots are usually particles with an average particle size of 20 nm or less, and can absorb and convert light energy. The quantum dots can adjust the color of light by changing their particle size. Since the band gap is determined by the particle size, light with high color purity can be obtained by aligning the particle size.

[0068] Quantum dots that emit in the visible light range include CdS, ZnSe, and CdSe-based particles with a shell such as ZnS. Cadmium-free quantum dots such as InP, CuInS2, AgInS2, Te, PbS, and InAs can also be used. Any type of conventional quantum dot can be used in the present invention.

[0069] The amount of quantum dots added is preferably 0.01 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the solid content of the radical-curable silicone composition.

[0070] [Other ingredients] The radical curing silicone composition of the present invention may contain a known antioxidant such as 2,6-di-t-butyl-4-methylphenol in order to suppress the occurrence of coloration, cloudiness, oxidative deterioration, etc. of the cured product. In addition, a light stabilizer such as a hindered amine stabilizer may be added to impart resistance to photodegradation. Furthermore, if necessary, an inorganic filler such as fumed silica may be added to improve strength, or a dye, pigment, flame retardant, etc. may be added. An adhesive assistant (silane coupling agent) may be added to improve adhesion.

[0071] [Curing method and conditions] The radical curable silicone composition of the present invention can be cured by known methods and conditions. For example, the composition can be cured at 50 to 150°C for 10 minutes to 5 hours. When the polymerization initiator is an organic peroxide with a 10-hour half-life temperature of 50 to 150°C, low-temperature curing is possible.

[0072] [Silicone cured product] The present invention also provides a silicone cured product, which is a cured product of the above radically curable silicone composition.

[0073] The silicone cured product of the present invention has good hardness and can be cured at low temperatures, which reduces the thermal effects on phosphors, quantum dots, etc. Therefore, it is useful for applications such as wavelength conversion materials, such as sheets with phosphors dispersed therein, and sealing materials. EXAMPLES

[0074] The present invention will be specifically described below using examples, but these examples do not limit the present invention in any way. In the following, Me is an abbreviation for methyl group, Ph is an abbreviation for phenyl group, and Vi is an abbreviation for vinyl group. The weight average molecular weight was determined as a polystyrene equivalent value by GPC analysis using toluene as a developing solvent. The viscosity at 25°C was determined using a B-type rotational viscometer.

[0075] [Synthesis Example 1] (Me3SiO 1 / 2 ) 0.40 (ViMe2SiO 1 / 2 ) 0.05 (SiO2) 0.55 1000 parts by mass of a 50% toluene solution of organopolysiloxane having a weight average molecular weight of 5300 and a structural unit ratio represented by the formula (1) was heated to 80°C in an oil bath. 0.54 g of a toluene solution of platinum hexachloride 1,3-divinyltetramethyldisiloxane (0.5 mass% in terms of platinum) was added thereto, and 22 g (0.17 moles) of a compound represented by the following formula (4) was added dropwise while stirring. After completion of the dropwise addition, the mixture was stirred at 90°C for 2 hours, and then cooled to 25°C. Further, 300 g of methanol was added, stirred for 30 minutes, and then allowed to stand and separate. Decandation was performed, and methanol was removed under reduced pressure at 100°C. Further, 56 g of ethyl acetate was added and dissolved, and (Me3SiO 1 / 2 ) 0.40 (ViMe2SiO 1 / 2 ) 0.04 (R 3 Me2SiO 1 / 2 ) 0.01 (SiO2) 0.55 Thus, a 50% by mass ethyl acetate solution (A-1) of a three-dimensional network organopolysiloxane having a structural unit ratio represented by the following formula was obtained. [ka] (In the formula, * represents a bond to an adjacent silicon atom.)

[0076] [Synthesis Example 2] The same procedure as in Synthesis Example 1 was carried out, except that the amount of the compound represented by the above formula (4) added was changed to 44 g (0.34 mol), (MeSiO 1 / 2 ) 0.40 (ViMe2SiO 1 / 2 ) 0.03 (R 3 Me2SiO 1 / 2 ) 0.02 (SiO2) 0.55 Thus, a 50% by mass ethyl acetate solution (A-2) of a three-dimensional network organopolysiloxane having a structural unit ratio represented by the following formula was obtained.

[0077] [ka] (In the formula, * represents a bond to an adjacent silicon atom.)

[0078] [Synthesis Example 3] In a 1000mL four-neck flask equipped with a stirrer, a condenser, a dropping funnel, and a thermometer, 300g of the organopolysiloxane represented by the following formula (5) (Vi: 0.0037 mol / 100g) was dissolved in 150g of toluene and heated to 85°C in an oil bath. 0.12g of a toluene solution of platinum hexachloride 1,3-divinyltetramethyldisiloxane (0.5 mass% in terms of platinum) was added to this, and 2.89g (0.011 mol) of the compound represented by the following formula (5) was added dropwise while stirring. After the dropwise addition was completed, the mixture was stirred at 90°C for 2 hours, and then the toluene was distilled off under reduced pressure to obtain 300g of a colorless, transparent, oily linear organopolysiloxane (B-1) (viscosity at 25°C: 14 Pa·s).

[0079] [ka] (In the formula, the order of the siloxane units in parentheses is not specified.)

[0080] [Synthesis Example 4] In a 1000 mL four-neck flask equipped with a stirrer, a condenser, a dropping funnel, and a thermometer, 300 g of the organopolysiloxane represented by the following formula (6) (Vi group: 0.0025 mol / 100 g) was dissolved in 150 g of toluene and heated to 85°C in an oil bath. 0.06 g of a toluene solution of platinum hexachloride 1,3-divinyltetramethyldisiloxane (0.5 mass% in terms of platinum) was added to this, and 2.0 g (0.0075 mol) of the compound represented by the following formula (6) was added dropwise while stirring. After the dropwise addition was completed, the mixture was stirred at 90°C for 2 hours, and then the toluene was distilled off under reduced pressure to obtain 290 g of a colorless, transparent, oily linear organopolysiloxane (B-2) (viscosity at 25°C: 110 Pa·s).

[0081] [ka] (In the formula, the order of the siloxane units in parentheses is not specified.)

[0082] [Examples 1 and 2 and Comparative Examples 1 and 2] The components shown below were mixed in the compounding ratios (parts by mass) shown in Table 1 to prepare radically curable silicone compositions.

[0083] (A) Component: (A-1) 50% by mass ethyl acetate solution of the three-dimensional network organopolysiloxane obtained in Synthesis Example 1 (A-2) 50% by mass ethyl acetate solution of the three-dimensional network organopolysiloxane obtained in Synthesis Example 2 (A-3)(MeSiO 1 / 2 ) 0.40 (ViMe2SiO 1 / 2 ) 0.05 (SiO2) 0.55 A 50% by weight ethyl acetate solution of a three-dimensional network organopolysiloxane (weight average molecular weight 5300) having a structural unit ratio represented by the following formula:

[0084] (B) Ingredients: (B-1) Linear organopolysiloxane obtained in Synthesis Example 3 (B-2) Linear organopolysiloxane obtained in Synthesis Example 4

[0085] (C) Ingredients: Perhexa (registered trademark) 25O (NOF Corporation, 10-hour half-life temperature in benzene at a peroxide concentration of 0.05 mol / L: 66.2°C)

[0086] Component (D): Ethyl acetate

[0087] [Table 1]

[0088] The resulting composition was poured into a 4 mm thick polytetrafluoroethylene frame and heated at 80° C. for 2 hours to prepare a sheet. The obtained sheet was subjected to the following tests, and the physical properties were evaluated. The results are shown in Table 2.

[0089] [exterior] The appearance was visually observed, with transparency being rated as ◯ and opacity being rated as ×.

[0090] [Solubility] The solubility in toluene was confirmed. If it is soluble in toluene, it means that it is uncured, and if it is insoluble, it means that it is cured.

[0091] [hardness] Type D hardness was measured at 23°C.

[0092] [Table 2]

[0093] As shown in Table 2, in Examples 1 and 2, which used the radical-curable organopolysiloxane composition of the present invention, curing was possible at relatively low temperatures, and a cured product with excellent hardness was obtained. On the other hand, the (A) component is R 3In Comparative Example 1, in which the component (B) was changed to a three-dimensional network organopolysiloxane having no radical polymerizable functional group, represented by the following formula:

[0094] The present specification includes the following aspects. [1]: (A) a three-dimensional network organopolysiloxane represented by the following formula (1): (R 1 3SiO 1 / 2 ) m1 (R 2 R 1 2SiO 1 / 2 ) m2 (R 3 R 1 2SiO 1 / 2 ) m3 (SiO 4 / 2 ) q (1) (In the formula, R 1 are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and containing no aliphatic unsaturated bonds; R 2 is an alkenyl group having 2 to 8 carbon atoms, R 3 is a substituent having a radically polymerizable functional group. m1, m2, m3, and q are numbers that satisfy m1≧0, m2≧0, m3>0, and q>0, and that satisfy m1+m2+m3+q=1. (B) a linear organopolysiloxane having a phenyl group bonded to a silicon atom and a substituent having a radically polymerizable functional group; (C) a polymerization initiator, and (D) Solvent A radical curable silicone composition comprising: [2]: The radical-curable silicone composition according to [1], wherein the component (B) is a linear organopolysiloxane represented by the following formula (3): (R 2 R 1 2SiO 1 / 2 ) m4 (R 3 R 1 2SiO1 / 2 ) m5 (R 1 2SiO 2 / 2 ) d1 (R 1 R 2 SiO 2 / 2 ) d2 (R 1 R 3 SiO 2 / 2 ) d3 (3) (In the formula, R 1 , R 2 and R 3 has the same meaning as above, except that all R 1 are phenyl groups, and m4, m5, d1, d2, and d3 are numbers that satisfy m4≧0, m5≧0, d1≧0, d2≧0, and d3≧0, respectively, and m4+m5>0, m5+d3>0, and m4+m5+d1+d2+d3=1. [3]: The above R 3 is a group represented by the following formula (2): [ka] (In the formula, R 1 has the same meaning as above, and R 4 are each independently a substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms, R 5 is a hydrogen atom or a methyl group, and * represents a bond to an adjacent silicon atom. [4]: The radical-curable silicone composition according to any one of [1] to [3], wherein the polymerization initiator is an organic peroxide. [5]: The radical-curable silicone composition according to [4], wherein the organic peroxide has a 10-hour half-life temperature of 50 to 150°C. [6]: A silicone cured product, which is a cured product of the radical-curable silicone composition according to any one of [1] to [5].

[0095] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. (A) a three-dimensional network organopolysiloxane represented by the following formula (1): (R １ ３ SiO １／２ ) ｍ１ (R ２ R １ ２ SiO １／２ ) ｍ２ (R ３ R １ ２ SiO １／２ ) ｍ３ (SiO ４／２ ) ｑ (1) (In the formula, R １ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and containing no aliphatic unsaturated bonds; R ２ is an alkenyl group having 2 to 8 carbon atoms, R ３ is a substituent having a radical polymerizable functional group. m1, m2, m3, and q are numbers that satisfy m1 ≧ 0, m2 ≧ 0, m3 > 0, and q > 0, and that satisfy m1 + m2 + m3 + q = 1. (B) a linear organopolysiloxane having a phenyl group bonded to a silicon atom and a substituent having a radically polymerizable functional group; (C) a polymerization initiator, and (D) Solvent A radical curable silicone composition comprising:

2. 2. The radical-curable silicone composition according to claim 1, wherein the component (B) is a linear organopolysiloxane represented by the following formula (3): (R ２ R １ ２ SiO １／２ ) ｍ４ (R ３ R １ ２ SiO １／２ ) ｍ５ (R １ ２ SiO ２／２ ) ｄ１ (R １ R ２ SiO ２／２ ) ｄ２ (R １ R ３ SiO ２／２ ) ｄ３ (3) (In the formula, R １ , R ２ and R ３ has the same meaning as above, except that all R １ are phenyl groups, and m4, m5, d1, d2, and d3 are numbers that satisfy m4≧0, m5≧0, d1≧0, d2≧0, and d3≧0, respectively, and m4+m5>0, m5+d3>0, and m4+m5+d1+d2+d3=1.

3. The R ３ 2. The radical-curable silicone composition according to claim 1, wherein: 【Chemistry 1】 (In the formula, R １ has the same meaning as above, R ４ are each independently a substituted or unsubstituted divalent hydrocarbon group having 1 to 8 carbon atoms; R ５ is a hydrogen atom or a methyl group, and * represents a bond to an adjacent silicon atom.

4. 2. The radical-curable silicone composition according to claim 1, wherein the polymerization initiator is an organic peroxide.

5. 5. The radical-curable silicone composition according to claim 4, wherein the organic peroxide has a 10-hour half-life temperature of 50 to 150°C.

6. A silicone cured product, which is a cured product of the radical-curable silicone composition according to any one of claims 1 to 5.

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