Radical-curable silicone composition and cured silicone 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 radical-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 aesthetic appeal, and their market is rapidly expanding not only for use in liquid crystal display (LCD) backlights and automotive applications such as car headlights, but also for general lighting. Such LED lights are constructed by encapsulating an LED chip mounted on a substrate with a transparent resin encapsulant. Addition-curable silicone compositions are widely used as encapsulants for encapsulating LEDs because of their excellent heat resistance.

[0003] Because the emission spectrum of an LED depends on the semiconductor material that makes up 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 to 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, or placing red, green, and blue phosphors on an ultraviolet-emitting LED chip. Of these, the methods of placing a yellow phosphor on a blue LED and placing red and green phosphors on a blue LED are currently the most widely used, due to the luminous efficiency and cost of the LED chip.

[0004] One specific method proposed for placing phosphors on LED chips involves dispersing phosphors in a silicone composition containing an alkenyl-group-containing organopolysiloxane and a hydrogen organopolysiloxane, and then attaching a sheet cured by a hydrosilylation reaction using a platinum group metal catalyst (Patent Documents 1 to 5). However, when using such addition-curable silicone resins as phosphor binders, curing can be inhibited by catalyst poisons contained in the phosphors. Furthermore, because high-temperature heating is required to cure such addition-curable silicone compositions, it has been difficult to use phosphors with poor heat resistance.

[0005] The present inventors previously proposed a radical-curing silicone composition that can be cured at low temperatures without being affected by catalyst poisons (Patent Document 6). However, sheets formed from this composition had low hardness, resulting in problems such as insufficient strength and the sheets stretching during handling. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-1791 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-1792 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-138216 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-114446 [Patent Document 5] Japanese Patent Application Laid-Open No. 2014-116598 [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 no aliphatic unsaturated bond, and R 2 is an alkenyl group having 2 to 8 carbon atoms, and 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 silicon-bonded phenyl group 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 produce 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 also contains the above-mentioned R 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, and 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 organic peroxides provide excellent storage stability and controllability of the curing properties of the composition, and can be cured at low temperatures, thereby suppressing the thermal effects on the phosphor.

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

[0019] The silicone cured product of the present invention has good hardness and is therefore useful as a wavelength conversion material such as a sheet containing dispersed phosphors or as an encapsulant. [Effects of the Invention]

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

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

[0022] That is, 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 no aliphatic unsaturated bond, and R 2 is an alkenyl group having 2 to 8 carbon atoms, and 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 silicon-bonded phenyl group 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 curable silicone composition] The radically curable silicone composition of the present invention contains the following components (A) to (D) as essential components. In addition to the essential components, this composition can also contain optional components as needed. 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 no aliphatic unsaturated bond, and R 2 is an alkenyl group having 2 to 8 carbon atoms, and 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.

[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 m1≧0, m2≧0, m3>0, and q>0, respectively, and are numbers that satisfy the equation m1+m2+m3+q=1. The above three-dimensional network organopolysiloxane contains m3 units and q units as essential units, and R 3 The component (A) has a radical polymerizable R group. 3 The presence of the group enables radical curing at low temperatures, and the hardness of the cured product is improved by radical crosslinking. The m1, m2, and m3 units may each be a combination of two or more different siloxane units (small units), and the arrangement order of the small units in each of the 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, and 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 methylene, ethylene, propylene, trimethylene, pentamethylene, hexamethylene, heptamethylene, or octamethylene, preferably one having 1 to 4 carbon atoms, with methylene, ethylene, propylene, and trimethylene being particularly preferred. The hydrogen atoms in these groups may be further substituted with any substituent (such as a halogen atom).

[0031] From the viewpoint of the ease of handling 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. Furthermore, 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 component (A) is preferably 1,000 to 20,000, and more preferably 2,000 to 10,000. 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 be used alone or in combination of two or more.

[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] 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 of each unit, m4, m5, d1, d2, and d3, 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 both. 3 The presence of the group allows for radical curing at low temperatures. The m4, m5, d1, d2, and d3 units may each be a combination of two or more different siloxane units (small units), and the arrangement order of the small units in each of the units is arbitrary (undefined).

[0039] Here, R 1 are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and containing no aliphatic unsaturated bonds. 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. Methyl and phenyl groups are particularly preferred.

[0040] From the viewpoint of compatibility of the composition and transparency of the cured product, all 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, and 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 one represented by the above formula (2).

[0043] In the above formula (3), it is preferable that m4 is 0 and d2 is 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 (subunits). Examples of such D units include ((CH3)2SiO 2 / 2 ), ((C6H5)2SiO 2 / 2 ), ((C6H5)(CH3)SiO 2 / 2 ) and combinations 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 formula, Me represents a methyl group, and Ph represents a phenyl group (the same applies hereinafter). [ka] (In the formula, the siloxane units in the parentheses may be arranged in any order, and * represents a bond to an adjacent silicon atom.) [ka] (In the formula, the siloxane units in the parentheses may be arranged in any order.) [ka] (In the formula, the siloxane units in the parentheses may be arranged in any order.)

[0045] The amount of the linear organopolysiloxane (B) added is preferably 10 to 1000 parts by mass, 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 within a more appropriate range.

[0046] [(C) component] Component (C) is a polymerization initiator that polymerizes the polymerizable functional groups of components (A) and (B). Component (C) can be an organic peroxide that generates radicals when exposed to heat.

[0047] As the organic peroxide, from the viewpoint of storage stability of the composition and control of curability, 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-di-tetrabutylperoxy-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] Organic peroxides are also 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 any effective amount, typically 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of component (A).

[0053] [(D) component] 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 these, toluene, heptane, and ethyl acetate are preferred.

[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 the application of the composition.

[0055] In addition to the components (A) to (D), the radically curable silicone composition of the present invention may further contain the following optional components as needed.

[0056] [Phosphor] By adding a phosphor, the radical-curable silicone composition of the present invention can be used as a wavelength conversion material such as a phosphor sheet. The phosphor absorbs blue, purple, or ultraviolet light emitted from an LED chip and converts its wavelength, emitting light of a different wavelength from the LED chip light, which has a wavelength in the red, orange, yellow, green, or blue region. This allows a portion of the light emitted from the LED chip to mix with a portion of the light emitted from the phosphor, resulting in a multicolor LED that includes white.

[0057] The above-mentioned phosphors include various phosphors such as those that emit green light, those that emit blue light, those that emit yellow light, and those that emit red light. Specific phosphors that can be used in the present invention include known phosphors such as organic phosphors, inorganic phosphors, fluorescent pigments, and fluorescent dyes. Examples of organic phosphors include allyl sulfamide-melamine formaldehyde co-condensation dyes and perylene-based phosphors, with perylene-based phosphors being preferred due to their long-term usability. Examples of fluorescent substances that are particularly preferred 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, and Ba)2B5O9Cl:Eu,Mn, and (at least one of Mg, Ca, Sr, and Ba)(PO4)6Cl2:Eu,Mn.

[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-based phosphors). Specifically, Ln3MO 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] As phosphors that emit red light, for example, there are Y2O2S:Eu, La2O2S:Eu, Y2O3:Eu, Gd2O2S:Eu, etc.

[0062] Also, as phosphors that emit light corresponding to blue LEDs, there are 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, further (Ba,Sr,Ca)Si2O2N2:Eu-based phosphors, Ca8MgSi4O 16 Cl^2: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 desired emission color.

[0065] The particle size of the phosphor is not particularly limited, but a D50 of 0.05 μm or more is preferred, and a D50 of 3 μm or more is more preferred. A D50 of 30 μm or less is also preferred, and a D50 of 20 μm or less is more preferred. Here, D50 refers to the particle diameter at which the cumulative passing fraction from the small particle size side reaches 50% in the volume-based particle size distribution obtained by measurement using a laser diffraction / scattering particle size distribution measurement method. When D50 is within this range, the phosphor disperses well in the phosphor sheet, resulting in stable light emission.

[0066] In the present invention, the phosphor content 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 solids content of the radical-curable silicone composition. By setting the phosphor content in the phosphor sheet within this 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 radically curable silicone composition of the present invention can also contain quantum dots, which act as wavelength conversion materials. Quantum dots are typically particles with an average particle size of 20 nm or less, and are capable of absorbing and converting light energy. The color of light emitted by quantum dots can be adjusted by varying their particle size. Because the band gap is determined by the particle size, light with high color purity can be obtained by adjusting the particle size.

[0068] Quantum dots that emit in the visible light range include CdS, ZnSe, and CdSe-based particles with a ZnS shell. 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-curable silicone composition of the present invention may contain a known antioxidant such as 2,6-di-t-butyl-4-methylphenol to prevent the occurrence of coloration, cloudiness, oxidative degradation, etc. in the cured product. Furthermore, a light stabilizer such as a hindered amine stabilizer may be contained to impart resistance to photodegradation. Furthermore, if necessary, an inorganic filler such as fumed silica may be contained to improve strength, and dyes, pigments, flame retardants, etc. may also be contained. An adhesion promoter (silane coupling agent) may also be contained to improve adhesive strength.

[0071] [Curing method and conditions] Known methods and conditions can be used to cure the radically curable silicone composition of the present invention. 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] [Cured silicone] The present invention also provides a cured silicone product, which is a cured product of the above radical-curable silicone composition.

[0073] The silicone cured product of the present invention has good hardness and can be cured at low temperatures, thereby suppressing the thermal effects on phosphors, quantum dots, etc. For this reason, it is useful as a wavelength conversion material, such as a sheet or encapsulant containing dispersed phosphors, etc. [Example]

[0074] The present invention will be described in detail 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 following formula (4) was heated to 80°C in an oil bath. 0.54 g of a toluene solution of platinum hexachloride 1,3-divinyltetramethyldisiloxane (0.5% by mass in terms of platinum) was added to the solution, and 22 g of a compound represented by the following formula (4) ( 0.084 After the dropwise addition was completed, the mixture was stirred at 90°C for 2 hours and then cooled to 25°C. 300 g of methanol was further added, and the mixture was stirred for 30 minutes, then allowed to stand and separated. Decandation was performed, and the methanol was removed under reduced pressure at 100°C. 56 g of ethyl acetate was further added and dissolved, and (MeSiO 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] In Synthesis Example 1, the amount of the compound represented by the above formula (4) added was 44 g ( 0.17The same procedure as in Synthesis Example 1 was carried out, except that the (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 1000 mL four-neck flask equipped with a stirrer, a condenser, a dropping funnel, and a thermometer, 300 g of organopolysiloxane represented by the following formula (5) (Vi: 0.0037 mol / 100 g) was dissolved in 150 g of toluene, and the solution was heated to 85° C. in an oil bath. To this was added 0.12 g of a toluene solution of platinum hexachloride 1,3-divinyltetramethyldisiloxane (0.5 mass % in terms of platinum), and the mixture was stirred. superior Notation ( 4 ), 2.89 g (0.011 mol) of the compound represented by the formula (I) was added dropwise. After the addition was complete, the mixture was stirred at 90°C for 2 hours, and then the toluene was distilled off under reduced pressure, yielding 300 g 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 organopolysiloxane represented by the following formula (6) (Vi group: 0.0025 mol / 100 g) was dissolved in 150 g of toluene, and the solution was heated to 85° C. in an oil bath. To this was added 0.06 g of a toluene solution of platinum hexachloride 1,3-divinyltetramethyldisiloxane (0.5 mass % in terms of platinum), and the mixture was stirred. superior Notation ( 4 2.0 g of the compound represented by After the addition was complete, 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 blending 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 mass ethyl acetate solution of a three-dimensional network organopolysiloxane (weight average molecular weight 5300) having a structural unit ratio represented by

[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 of 66.2°C in benzene at a peroxide concentration of 0.05 mol / L)

[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 form 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, and transparency was marked with a circle, and cloudiness was marked with an X.

[0090] [Solubility] The solubility in toluene was confirmed. If it was soluble in toluene, it was uncured, and if it was insoluble, it was 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 cured products with excellent hardness were obtained. On the other hand, component (A) is R 3In Comparative Example 1, in which component (B) was changed to a three-dimensional network organopolysiloxane having no radically polymerizable functional groups represented by the formula (I), curing was insufficient, and in Comparative Example 2, in which component (B) was changed to a linear organopolysiloxane having no phenyl groups, the composition was incompatible and became cloudy.

[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 no aliphatic unsaturated bond, and R 2 is an alkenyl group having 2 to 8 carbon atoms, and 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 silicon-bonded phenyl group 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, and 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, characterized by being 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 embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within 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 no aliphatic unsaturated bond, and R ２ is an alkenyl group having 2 to 8 carbon atoms, and R ３ is a substituent having a radically polymerizable functional group and represented by the following formula (2). m1, m2, m3, and q are numbers that satisfy m1≧0, m2≧0, m3>0, and q>0, and also satisfy m1+m2+m3+q=1. 【Chemistry 1】 (In the formula, R 1 has the same meaning as above, each R 4 is 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.) (B) a linear organopolysiloxane having a silicon-bonded phenyl group and a substituent having a radically polymerizable functional group; (C) a polymerization initiator which is an organic peroxide, and (D) Solvent A radical-curable silicone composition comprising:

2. 2. The radical-curable silicone composition according to claim 1, wherein 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. 2. The radical-curable silicone composition according to claim 1, wherein the organic peroxide has a 10-hour half-life temperature of 50 to 150°C.

4. A cured silicone product, which is a cured product of the radical-curable silicone composition according to any one of claims 1 to 3.

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