WO2014092196A1

WO2014092196A1 - High-refractive index heat-conductive composition of exceptional transparence, heat-conductive grease comprising same, cured heat-conductive material, thermal-softening heat-conductive composition, and applications for same

Info

Publication number: WO2014092196A1
Application number: PCT/JP2013/083541
Authority: WO
Inventors: 和彦兒島; 大川　直; 通孝須藤; 晴彦古川
Original assignee: 東レ・ダウコーニング株式会社
Priority date: 2012-12-11
Filing date: 2013-12-10
Publication date: 2014-06-19
Also published as: TW201430064A

Abstract

Provided are a heat-conductive composition containing (A) 100 mass parts of an organosilicon compound having a refractive index of 1.550 or above at 25°C and (B) 10-2,000 mass parts of a heat-conductive filler; a heat-conductive grease comprising the heat-conductive composition; a cured heat-conductive material, preferably a heat-conductive gel or heat-conductive rubber, obtained by curing of the heat-conductive composition; and a thermal-softening heat-conductive composition comprising the heat-conductive composition. Further provided is an optical material, a heat-conductive for use in a semiconductor device, or a semiconductor device, that includes the heat-conductive composition or cured form thereof. The heat-conductive composition or cured form thereof has exceptional transparence and heat-conductivity and a high refractive index, and can be utilized as a heat-conductive material in various applications.

Description

High refractive index heat conductive composition excellent in transparency, heat conductive grease comprising the same, heat conductive hardened material, heat softening heat conductive composition and use thereof

The present invention relates to a thermally conductive composition having a matrix material composed of an organic silicon compound having a high refractive index and excellent in transparency and thermal conductivity of the composition or a cured product thereof. Furthermore, this invention relates to the use of the said heat conductive composition.

In recent years, there has been an increasing demand for high brightness and low power consumption for LED backlights and LED lighting used in liquid crystal panel displays and the like, and optical materials with higher light transmission and thermal conductivity have been demanded. It has been. Particularly in high-brightness light-emitting diodes, the amount of heat generated from the light-emitting elements is large, and it is difficult to meet the heat-dissipation requirements only with the heat-dissipation path using conventional lead frames and substrates. Alternatively, heat radiation from a sealant or the like of a light emitting element has been widely studied.
However, since these heat dissipation paths are also light-transmitting surfaces from the light emitting elements, in order to maintain low power consumption without impairing the luminance of the LED, the heat dissipation material has transparency in addition to excellent heat dissipation characteristics. Is required. However, the known heat dissipating material has a problem of poor transparency when a heat conductive filler such as carbon black or silica is used.
In order to solve these problems, by using a matrix material made of a resin material and a thermally conductive filler, by making the absolute value of the difference between the refractive index of the matrix material and the refractive index of the thermally conductive filler closer to 0, It has been proposed to obtain a heat radiating material having both light transmittance and thermal conductivity (see Patent Documents 1 to 4).
However, since these techniques realize transparency by the difference between the refractive index of the matrix material and the refractive index of the thermally conductive filler, particularly when trying to select a high refractive index thermally conductive filler, There is a problem that a matrix material suitable for this cannot be specifically provided, and it is substantially difficult to carry out the invention. For example, Patent Documents 1 to 3 exemplify thermally conductive fillers having a refractive index of more than 1.55 such as aluminum hydroxide in the specification, but the difference in refractive index is made less than 0.01. For this purpose, it is necessary to select a material having a refractive index of the matrix material of 1.54 or more, but such a material is not specifically disclosed. For this reason, the invention disclosed in these documents has a problem that it can be practically performed only with a heat conductive filler having a refractive index close to that of known silicone materials and organic transparent resins such as silica and crystallites. It was.
On the other hand, by using a surface treatment of a heat conductive filler such as silica or using a resin dispersant, a heat dissipation material having both high light transmittance and heat conductivity is obtained by finely dispersing the heat conductive filler. Has been proposed (see Patent Documents 5 to 6). However, both silica and hydrotalcite used in these methods have a refractive index of 1.55 or less, and when used in a matrix material having a high refractive index, there is a problem that the transparency that is the object of the invention is impaired. there were.
As a result, conventionally known heat radiating materials with excellent light transmittance and thermal conductivity must be relatively low refractive index materials, and when the heat radiating materials are applied to high-intensity type light emitting diodes, etc. It was not possible to avoid adverse effects on luminance and light emission efficiency, such as a decrease in light extraction efficiency.

JP 2010-248311 A JP 2012-083548 A JP 2012-082314 A JP 2011-144360 A International Patent Publication WO2012 / 093602 International Patent Publication WO2011-111414

An object of the present invention is to provide a thermally conductive composition that is excellent in transparency and thermal conductivity of the composition or a cured product thereof, has a high refractive index, and can be used as a thermally conductive material for various applications. Is to provide. Another object of the present invention is to provide a thermally conductive grease comprising the thermally conductive composition, a thermally conductive grease, preferably a thermally conductive gel or a thermally conductive rubber obtained by curing the thermally conductive composition. It is to provide a heat-softening heat conductive composition comprising a cured product and the heat conductive composition. Similarly, the objective of this invention is providing the optical material, the heat conductive member for semiconductor devices, or an optical semiconductor device containing this heat conductive composition or its hardened | cured material.

The inventors of the present invention have arrived at the present invention as a result of intensive studies in order to solve the above problems. That is, an object of the present invention is (A) heat conduction containing 100 parts by mass of an organosilicon compound having a refractive index of 1.550 or more at 25 ° C. and (B) 10 to 2000 parts by mass of a thermally conductive filler. Achieved by the sex composition. In particular, the component (A) is an organosilicon compound having a refractive index of 1.550 to 1.750 at 25 ° C., and the component (B) has a refractive index of 1.500 to 1 at 25 ° C. Thermal conductivity filler is 20 to 1000 parts by mass, and the difference in refractive index between the matrix material composed of the organosilicon compound and the thermally conductive filler is 0.050 or less in absolute value. It is more suitably achieved by the sex composition. In particular, the high refractive index organosilicon compound as component (A) is a specific organopolysiloxane or a specific polyorganometallosiloxane having a condensed polycyclic aromatic group such as a naphthyl group or a condensed polycyclic aromatic group-containing group. In addition, it is preferable to include one or more kinds selected from high-refractive-index organosilicon compounds containing a high polar group and the like, and the thermally conductive filler as the component (B) is aluminum hydroxide or magnesium hydroxide. It is preferable that it is one or more types of thermally conductive fillers selected from magnesium carbonate and boehmite.
Another object of the present invention is to provide a thermally conductive grease comprising the thermally conductive composition, a thermally conductive grease, preferably a thermally conductive gel or a thermally conductive rubber obtained by curing the thermally conductive composition. It is suitably achieved by a heat-softening heat conductive composition comprising the cured product and the heat conductive composition. Furthermore, it is suitably achieved by an optical material, a heat conductive member for a semiconductor device or an optical semiconductor device containing the heat conductive composition or a cured product thereof.
That is, the purpose is
[1] (A) 100 parts by mass of an organosilicon compound having a refractive index at 25 ° C. of 1.550 or more,
(B) Thermally conductive filler A thermally conductive composition comprising 10 to 2000 parts by mass.
[2] (A1) 100 parts by mass of an organosilicon compound having a refractive index of 1.550 to 1.750 at 25 ° C.
(B1) Thermally conductive filler having a refractive index at 25 ° C. of 1.500 to 1.800 20 to 500 parts by mass, comprising the matrix material composed of component (A1) and the refractive index of component (B1) The heat conductive composition according to [1], in which the difference in absolute value is 0.050 or less.
[3] The organosilicon compound as component (A) or component (A1) comprises one or more organosilicon compounds represented by the following (A1-1) to (A1-3): The heat conductive composition according to [1] or [2].
(A1-1) Average unit formula:
(R ¹ ₃ SiO _1/2 ) _a (R ¹ ₂ SiO _2/2 ) _b (R ² SiO _3/2 ) _c (SiO _4/2 ) _d
Wherein R ¹ is an alkyl group, an alkenyl group, a phenyl group, a hydrogen atom or a hydroxyl group, R ² is a phenyl group, a condensed polycyclic aromatic group or a condensed polycyclic aromatic group-containing group, a , B, c, and d are 0.01 ≦ a ≦ 0.8, 0 ≦ b ≦ 0.5, 0.2 ≦ c ≦ 0.9, 0 ≦ d <0.2, and a + b + c + d, respectively. = A number that satisfies 1.)
An organopolysiloxane represented by
(A1-2) General formula (1):
MO _{x / 2}
(In the formula, M is an atom of groups 2A, 2B, 4A, 5A in the periodic table, and x is a valence of M.)
A metalloxy unit represented by the general formula (2):
R ⁴ _a SiO _{(4-a) / 2}
(In the formula, R ⁴ is an alkyl group, an alkenyl group, an aryl group, an aralkyl group, or a hydrogen atom, and a is a number that satisfies 0 <a ≦ 3.)
A polyorganometallosiloxane comprising at least an organosiloxane unit represented by:
(A1-3) The following average structural formula:
(R ^M ₃ SiO _1/2 ) _a (R ^D ₂ SiO _2/2 ) _b (R ^T SiO _3/2 ) _c (SiO _4/2 ) _d
(Wherein R ^M , R ^D and R ^T are each independently
A monopolar hydrocarbon group, a hydrogen atom, a hydroxyl group, an alkoxy group, a highly polar functional group bonded to a silicon atom via a (n + 1) -valent functional group (Z) represented by -Z- (Q) n or directly A group having a functional group (Q) selected from a hydroxyl group-containing group, a silicon atom-containing hydrolyzable group or a metal salt derivative thereof, or a divalent functional group bonded to the Si atom of another siloxane unit. ,
Of all R ^M , R ^D and R ^T , 50 mol% or more of the monovalent hydrocarbon group is a phenyl group or a naphthyl group,
The molecule contains at least one group represented by -Z- (Q) n. n is a number of 1 or more, a to d are each 0 or a positive number, and a + b + c + d is a number in the range of 2 to 1000. )
An organosilicon compound represented by:
[4] The thermal conductivity according to any one of [1] to [3], wherein the thermal conductive composition or a cured product thereof has a light transmittance of 600% at a thickness of 0.2 mm of 65% or more. Composition.
[5] The component (B) or the component (B1) is one or more thermally conductive fillers selected from metal hydroxides, metal carbonates, and metal oxide hydrates. ]-[4] The heat conductive composition in any one of.
[6] The component (B) or the component (B1) is one or more kinds of thermally conductive fillers selected from aluminum hydroxide, magnesium hydroxide, magnesium carbonate, and boehmite, [1] to [5 ] The heat conductive composition in any one of.
[7] The heat conductive composition according to any one of [1] to [6], which is a heat conductive grease.
[8] The heat conductive composition according to any one of [1] to [7], wherein the heat conductive composition is cured to form a heat conductive gel or a heat conductive rubber. .
[9] The heat conductive composition containing the organosilicon compound as component (A) or component (A1) is solid at 25 ° C., and the heat softening temperature of the heat conductive composition is in the range of 40 to 115 ° C. The heat conductive composition according to any one of [1] to [7], wherein
[10] A thermally conductive cured product obtained by curing the thermally conductive composition according to [8].
[11] The thermally conductive composition according to [9] or the thermally conductive cured product according to [10], which is in a sheet form at 25 ° C.
[12] An optical material comprising the thermally conductive composition according to any one of [1] to [9] or the thermally conductive cured product according to [10] to [11].
[13] A thermally conductive member for a semiconductor device comprising the thermally conductive composition according to any one of [1] to [9] or the thermally conductive cured product according to [10] to [11].
[14] An optical semiconductor device comprising the thermally conductive composition according to any one of [1] to [9] or the thermally conductive cured product according to [10] to [11].
Is achieved.

According to the present invention, there is provided a thermally conductive composition that is excellent in transparency and thermal conductivity of the composition or a cured product thereof, has a high refractive index, and can be used as a thermally conductive material for various applications. be able to. Further, according to the present invention, a thermally conductive grease comprising the thermally conductive composition, and a thermally conductive cured product, preferably a thermally conductive gel or a thermally conductive rubber, obtained by curing the thermally conductive composition. A heat softening heat conductive composition comprising the heat conductive composition can be provided. Similarly, according to the present invention, an optical material, a thermally conductive member for a semiconductor device, or an optical semiconductor device including the thermally conductive composition or a cured product thereof can be provided.

The heat conductive composition according to the present invention is
(A) 100 parts by mass of an organosilicon compound having a refractive index at 25 ° C. of 1.550 or more,
(B) Thermally conductive filler 10 to 2000 parts by mass
It is characterized by containing. Specifically, such a heat conductive composition has a structure in which (B) a heat conductive filler is dispersed in a component (A) which is a polymer matrix material, and the composition is a curable and non-curable grease. Or a composition having a heat softening property. Hereinafter, each component will be described.
Component (A) is a polymer matrix material made of a high-refractive-index organosilicon compound consisting of one or a plurality of components or a reaction product thereof, and has a refractive index at 25 ° C. of 1.550 or more, preferably refractive The refractive index is 1.550 to 1.750, more preferably the refractive index is 1.555 to 1.700, and most preferably the refractive index is in the range of 1.560 to 1.680. The refractive index of the component (A) is a value obtained by measuring the organosilicon compound at 25 ° C. at a wavelength of 590 nm if the component (A) is non-curable, and if the component (A) is curable, This is a value obtained by measuring a cured product (= reactant) made of the organosilicon compound at 25 ° C. at a wavelength of 590 nm.
When the refractive index of the component (A) is less than the lower limit, both a method of minimizing the difference in refractive index from the thermally conductive filler and a method of surface treatment of the thermally conductive filler to be added have a high refractive index and a high refractive index. A transparent heat conductive composition or a heat conductive member cannot be obtained. This is because, in the method of minimizing the difference in refractive index from the thermally conductive filler, transparency is lost when a thermally conductive filler having a refractive index far from the refractive index of the matrix material is used in principle. Therefore, a highly transparent and high refractive index composition cannot be obtained. Similarly, even when a transparent composition is to be obtained by finely dispersing the thermally conductive filler to be added by surface treatment or the like, the resulting thermally conductive composition or the matrix material of the thermally conductive member is Since the refractive index is low, it is theoretically difficult to realize a high refractive index as the whole composition.
The organosilicon compound as component (A) is preferably (A1) an organosilicon compound having a refractive index of 1.550 to 1.750 at 25 ° C., and may be an organosilicon compound having the refractive index. The type is not particularly limited, and is an organopolysiloxane represented by the following structural formula, wherein 40 mol% or more of the monovalent organic groups bonded to the silicon atom are a condensed polycyclic ring such as a phenyl group or a naphthyl group. Examples thereof include an aromatic group or a condensed polycyclic aromatic group-containing group, with the remainder being a methyl group or the like. For example, phenylsiloxanes or naphthylsiloxanes such as trimethylpentaphenyltrisiloxane (refractive index 1.580) are included within the scope of component (A) of the present invention.
Structural formula (1-1):

Where R³Is a group selected from an alkyl group, a fluorinated alkyl group, an alkenyl group, a phenyl group, an aralkyl group, a hydrogen atom, a hydroxyl group, or a condensed polycyclic aromatic group or a condensed polycyclic aromatic group-containing group. A ratio of at least 40% is a phenyl group, a condensed polycyclic aromatic group or a condensed polycyclic aromatic group-containing group, and n1 is a number in the range of 0 to 1,000. Industrially preferred is R³Is a methyl group, a vinyl group, a phenyl group, a hydrogen atom, a hydroxyl group or a naphthyl group, and at least 50% of them are preferably a phenyl group or a naphthyl group. When component (A) is a non-reactive organopolysiloxane, the group other than the phenyl group, the condensed polycyclic aromatic group, or the condensed polycyclic aromatic group-containing group is preferably a methyl group. On the other hand, when the component (A) is a reactive organopolysiloxane, the group other than the phenyl group, the condensed polycyclic aromatic group, or the condensed polycyclic aromatic group-containing group is selected from an alkenyl group, a hydrogen atom, and a hydroxyl group. It is preferable to have at least one group.
However, the organosilicon compound as component (A) is particularly preferably one containing at least one organosilicon compound represented by the following (A1-1) to (A1-3). These are from a specific organopolysiloxane having a condensed polycyclic aromatic group or a condensed polycyclic aromatic group-containing group such as a naphthyl group, a specific polyorganometallosiloxane, a specific organosilicon compound containing a highly polar group, etc. One or more types selected, the refractive index of the matrix material can be designed to be higher than that of phenylsiloxanes, and the so-called phase change heat dissipation having grease, curable composition, and heat softening property There exists an advantage which can be utilized as a heat conductive material of various uses as a material. These organosilicon compounds represented by (A1-1) to (A1-3) may be used alone as the component (A) of the thermally conductive composition, or two or more kinds may be used in combination. The component (A) may be constituted as a reaction product with another reactive organosilicon compound (for example, organohydrogenpolysiloxane).
First, an organosilicon compound represented by the following (A1-1) is an organopolysiloxane having a resin structure having a condensed polycyclic aromatic group such as a naphthyl group or a group containing a condensed polycyclic aromatic group, and the present applicants. Can be produced in the same manner as the main components of the curable silicone composition proposed in Japanese Patent Application No. 2011-151312. Such an organosilicon compound may be used as a main component of a cured product that is cured by a hydrosilylation reaction to form a heat conductive member, and without curing, is a main component of a heat conductive grease or a heat softening heat conductive composition. It may be used as In addition, a heat conductive composition using such an organopolysiloxane having a resin structure has a heat softening temperature in the range of 40 to 115 ° C., so that a heat conductive composition having heat softening properties (= phase change material) is easy. There are advantages that can be realized.
(A1-1) Average unit formula:
(R¹ ₃SiO_1/2)_a(R¹ ₂SiO_2/2)_b(R²SiO_3/2)_c(SiO_4/2)_d
In the above formula, R¹Is an alkyl group, an alkenyl group, a phenyl group, or a hydrogen atom. R¹Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, and a methyl group is preferable. R¹Examples of the alkenyl group include a vinyl group, an allyl group, and a butenyl group, and is preferably a vinyl group.
Where R²Is a phenyl group or a condensed polycyclic aromatic group or a condensed polycyclic aromatic group-containing group. R²As the condensed polycyclic aromatic group, a naphthyl group, anthracenyl group, phenanthryl group, pyrenyl group, and a hydrogen atom of these condensed polycyclic aromatic groups are alkyl groups such as methyl group, ethyl group; methoxy group, ethoxy group An alkoxy group such as a chlorine atom, a group substituted with a halogen atom such as a bromine atom, and the like, and a naphthyl group is preferable. R²Examples of the condensed polycyclic aromatic group-containing group include condensed polycyclic aromatic group-containing alkyl groups such as naphthylethyl group, naphthylpropyl group, anthracenylethyl group, phenanthrylethyl group, and pyrenylethyl group, and their condensation Examples include a group in which a hydrogen atom of a polycyclic aromatic group is substituted with an alkyl group such as a methyl group or an ethyl group; an alkoxy group such as a methoxy group or an ethoxy group; a halogen atom such as a chlorine atom or a bromine atom.
In addition, it is preferable that the organosilicon compound represented by the formula (A1-1) has a functional group curable by hydrosilylation reaction in the molecule, and at least one R in one molecule.¹Is preferably an alkenyl group or a hydrogen atom. R¹The refractive index of the organosilicon compound represented by (A1-1) can be increased by increasing the proportion of phenyl groups in the whole. Similarly, R to which a phenyl group, a condensed polycyclic aromatic group, or a condensed polycyclic aromatic group-containing group is bonded.²SiO_3/2The refractive index of the organosilicon compound represented by (A1-1) can be increased by increasing the ratio c.
In the formula, a, b, c, and d are 0.01 ≦ a ≦ 0.8, 0 ≦ b ≦ 0.5, 0.2 ≦ c ≦ 0.9, and 0 ≦ d <0, respectively. .2 and a + b + c + d = 1, preferably 0.05 ≦ a ≦ 0.7, 0 ≦ b ≦ 0.4, 0.3 ≦ c ≦ 0.9, 0 ≦ d <0 2 and a number satisfying a + b + c + d = 1, particularly preferably 0.1 ≦ a ≦ 0.6, 0 ≦ b ≦ 0.3, 0.4 ≦ c ≦ 0.9, 0 ≦ d <. 0.2 and a number satisfying a + b + c + d = 1. This is because when a is less than the lower limit of the above range, the resulting organopolysiloxane changes from a liquid state to a solid state, and handling operability decreases, whereas when the upper limit of the above range is exceeded, The transparency of the cured product when the organosilicon compound represented by A1-1) is cured may decrease. Moreover, when b exceeds the upper limit of the said range, it will become sticky to the hardened | cured material at the time of hardening the organosilicon compound shown by (A1-1). When c is less than the lower limit of the above range, the refractive index of the composition using the organosilicon compound represented by (A1-1) or the cured product when the organosilicon compound is cured is significantly reduced. This is contrary to the object of the present invention. On the other hand, when c exceeds the upper limit of the above range, the cured product obtained by curing the organosilicon compound represented by (A1-1) may be too hard and brittle.
Here, when the component (A) is a matrix material composed of a cured product obtained by a hydrosilylation reaction, the refractive index at 25 ° C. of the cured product comprising the component (A1-1) and the crosslinking agent is 1.550 or more. It is necessary to be. Here, as the component (A1-1), an uncured component having a refractive index of 1.550 or more can be used, but a matrix made of an organosilicon compound obtained by a curing reaction by selecting a crosslinking agent or the like. When the refractive index of the material increases from before the curing, the component (A1-1) having a refractive index of less than 1.550, for example, a component having a refractive index of 1.530 or more may be used. Further, when a component having a refractive index of less than 1.550 is used as the component (A1-1), at least one hydrosilylation reactive functional group, at least one phenyl, or a condensed polycycle is used as a crosslinking agent. It is particularly desirable to use those containing an aromatic group or the like in the molecule. At that time, the component (A1-1) is more preferably in the uncured state and has a refractive index close to 1.550, and the refractive index is 1.535 or more, more preferably 1.540 or more. preferable. Further, the refractive index of the cured product obtained using the component (A1-1) is preferably 1.550 to 1.750, and particularly in the range of 1.570 to 1.650. Preferably there is.
When the organosilicon compound represented by (A1-1) is directly a matrix material in an uncured state, the component (A1-1) has an uncured refractive index of 1.550 or more at 25 ° C. It is necessary. At that time, the component (A1-1) preferably has a refractive index of 1.550 to 1.750 in an uncured state, and particularly has a refractive index in the range of 1.570 to 1.650. preferable. The organosilicon compound represented by (A1-1) having a high refractive index is represented by the following formula: 0.1 ≦ a ≦ 0.5, b = 0, 0.5 ≦ c ≦ 0.9, d = 0 And when it is a number satisfying a + b + c + d = 1, it can be obtained particularly suitably.
Next, the organosilicon compound defined by the following formula (A1-2) is a polyorganometallosiloxane. It can be produced in the same way as the components proposed in 61 / 666,031 and international patent applications based on its priority. Since such an organosilicon compound has a metalloxy unit, there is an advantage that a matrix material having a high refractive index exceeding a refractive index of 1.600 can be obtained relatively easily. Such a polyorganometallosiloxane may be used as a main component of a cured product that is cured by a hydrosilylation reaction to form a thermally conductive member, and without being cured, the thermal conductive grease or the thermal softening thermal conductive composition. You may use as a main ingredient.
(A1-2) General formula (1):
MO_{x / 2}
(In the formula, M is an atom of groups 2A, 2B, 4A, 5A in the periodic table, and x is a valence of M.)
A metalloxy unit represented by the general formula (2):
R⁴ _aSiO_{(4-a) / 2}
(Wherein R⁴Is an alkyl group, an alkenyl group, an aryl group, an aralkyl group, or a hydrogen atom, and a is a number satisfying 0 <a ≦ 3. )
A polyorganometallosiloxane comprising at least an organosiloxane unit represented by
Hereinafter, the polyorganometallosiloxane represented by (A1-2) will be described in detail.
The polyorganometallosiloxane has the general formula (1): MO_{x / 2}A metalloxy unit represented by the general formula (2): R⁴ _aSiO_{(4-a) / 2}It consists at least of the organosiloxane unit represented by these. Preferably, M is two or more different atoms selected from groups 2A, 2B, 4A, and 5A of the periodic table, and improves the refractive index, moisture resistance, and heat resistance of the resulting polyorganometallosiloxane. From the standpoint, it is particularly preferable that at least one atom of Group 4A or Group 5A of the periodic table and group 2A or Group 2B of the periodic table is included.
The metalloxy unit represented by the general formula (1) contains the metal atom M and is a component that improves the properties of the resulting polyorganometallosiloxane. Specifically, when an atom of Group 4A or Group 5A of the periodic table is included, the refractive index of the resulting polyorganometallosiloxane increases. Moreover, when the atom of 2A group or 2B group of the periodic table is contained, the heat resistance and moisture resistance of the polyorganometallosiloxane are improved. Further, when the group 4A or group 5A atom and at least one group 2A group or group 2B atom are included in the periodic table, the resulting polyorganometallosiloxane has a refractive index, moisture resistance and heat resistance. Be expected.
Therefore, the organosilicon compound defined by the formula (A1-2) is more preferably
General formula (1-1):
M¹O_{x / 2}
(Where M¹Are atoms in groups 4A or 5A of the periodic table, and x is M¹Is the valence of. )
A metalloxy unit represented by
General formula (1-2):
M²O_{y / 2}
(Where M²Is an atom of Group 2A or 2B of the periodic table, and y is M²Is the valence of. )
A metalloxy unit represented by
General formula (2):
R⁴ _aSiO_{(4-a) / 2}
(Wherein R⁴Is an alkyl group, an alkenyl group, an aryl group, an aralkyl group, or a hydrogen atom, and a is a number satisfying 0 <a ≦ 3. )
A polyorganometallosiloxane comprising at least an organosiloxane unit represented by the formula:
That is, preferably, the polyorganometallosiloxane represented by (A1-2) is represented by the general formula (1-1): M¹O_{x / 2}A metalloxy unit represented by the general formula (1-2): M²O_{y / 2}A metalloxy unit represented by the general formula (2): R⁴ _aSiO_{(4-a) / 2}It consists at least of the organosiloxane unit represented by these.
The metalloxy unit represented by the general formula (1-1) is a unit that increases the refractive index of the polyorganometallosiloxane. In general formula (1-1), M¹Is an atom of Group 4A or 5A in the periodic table, specifically, an atom selected from Group 4A atoms such as Ti, Zr, Hf, or Group 5A atoms such as V, Nb, Ta, etc. Preferably, Ti and Zr are used. In general formula (1), x is M.¹It is an integer of 1 to 7, depending on the type of atom. For example, the valence of Ti is 3 or 4, and the valence of Zr or Hf is 4.
The metalloxy unit represented by the general formula (1-2) is a unit that improves the heat resistance and moisture resistance of the polyorganometallosiloxane. In general formula (1-2), M²Is a group 2A or 2B group atom in the periodic table, specifically, an atom selected from a group 2A atom such as Ca, Sr, Ba, or a group 2B atom such as Zn, Cd, Hg, etc. In view of excellent heat resistance, Zn, Ca and Ba are preferable, and Zn is particularly preferable. In general formula (2), y is M.²It is an integer of 1 to 7, depending on the type of atom. For example, the valence of Zn, Ca, and Ba is 2.
The organosiloxy unit represented by the general formula (2) is a unit that improves the heat resistance, moisture resistance, and compatibility with organic polymers of the polyorganometallosiloxane. In general formula (3), R⁴Is an alkyl group, an alkenyl group, an aryl group, an aralkyl group, or a hydrogen atom. R⁴Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, and a methyl group is preferable. R⁴Examples of the alkenyl group include a vinyl group, an allyl group, and a butenyl group, and a vinyl group is preferable. R⁴As the aryl group, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, and a hydrogen atom of these aryl groups as an alkyl group such as a methyl group or an ethyl group; an alkoxy group such as a methoxy group or an ethoxy group; An aryl group substituted with a halogen atom such as a chlorine atom or a bromine atom is exemplified, and a phenyl group and a naphthyl group are preferable. R⁴Examples of the aralkyl group include a naphthylethyl group, a naphthylpropyl group, an anthracenylethyl group, a phenanthrylethyl group, a pyrenylethyl group, and a hydrogen atom of these aralkyl groups such as an alkyl group such as a methyl group or an ethyl group; And an aralkyl group substituted with a halogen atom such as a chlorine atom or a bromine atom. Since the polyorganometallosiloxane of the present invention can be hydrosilylation reactive, at least one R in one molecule.⁴Is preferably an alkenyl group or a hydrogen atom.
Further, in the general formula (2), a is a number satisfying 0 <a ≦ 3, and the refractive index of the polyorganometallosiloxane is increased and the compatibility with the organic polymer is improved. <A ≦ 3.
In the polyorganometallosiloxane, each of the metalloxy unit represented by the general formula (1-1), the metalloxy unit represented by the general formula (1-2), and the siloxane unit represented by the general formula (2) The content is such that the ratio of the content of the metalloxy unit represented by the general formula (1-1) and the siloxane unit represented by the general formula (2) is within a range of 0.01: 1 to 19: 1. In particular, it is preferably in the range of 0.5: 1 to 10: 1. The ratio of the content of the metalloxy unit represented by the general formula (1-2) and the siloxane unit represented by the general formula (2) is preferably within a range of 0.01: 1 to 19: 1. In particular, it is preferably in the range of 0.10: 1 to 10: 1. This is because when the content of the metalloxy unit represented by the general formula (1-1) is not more than the lower limit of the above range, the refractive index of the polyorganometallosiloxane is lowered, while the upper limit of the above range. It is because the compatibility with the organic polymer of polyorganometallosiloxane falls that it is above. Moreover, it is because the heat resistance and moisture resistance of polyorganometallosiloxane will fall that content of the metalloxy unit represented by General formula (1-2) is below the minimum of the said range, On the other hand, the said range It is because the refractive index of polyorganometallosiloxane will fall that it is more than the upper limit of this, and compatibility with an organic polymer will fall.
The matrix material composed of the organosilicon compound represented by (A1-2) or a cured product obtained by curing the same preferably has a refractive index of 1.550 to 1.750 at 25 ° C. The range of 1.560 to 1.700 is preferable. In particular, since the organosilicon compound represented by (A1-2) has a metalloxy unit, a high refractive index matrix material having a refractive index of 1.600 to 1.700 can be obtained. The organosilicon compound represented by (A1-2) having a high refractive index includes a metalloxy unit represented by the general formula (1-1), a metalloxy unit represented by the general formula (1-2), and a general formula. When the range of the content of each siloxane unit represented by (2) is in the range of 1 to 10: 0.10 to 10: 1, it can be particularly preferably obtained. At that time, M in the metalloxy unit represented by the general formula (1)¹Is Ti or Zr, and M in the metalloxy unit represented by the general formula (2)²Is Zn, Ca or Ba, and R in the general formula (3)⁴It is particularly preferable that at least 40 mol% of the above is a phenyl group or a naphthyl group. Further, when the organosilicon compound represented by (A1-2) is hydrosilylation reactive, at least one R in one molecule.⁴Is preferably an alkenyl group or a hydrogen atom.
In addition, the organosilicon compound defined by the following (A1-3) is a high bond bonded to a silicon atom via a (n + 1) -valent functional group (Z) represented by -Z- (Q) n or directly. It has a group having a functional group (Q) selected from a polar functional group, a hydroxyl group-containing group, a silicon atom-containing hydrolyzable group or a metal salt derivative thereof, and the silicon atom further contains another siloxane unit. It has a structure bonded to an oxygen atom (—O—) therein. Such an organosilicon compound can be produced in the same manner as the components proposed by the present applicants in Japanese Patent Application No. 2012-208701.
(A1-3) A highly polar functional group, a hydroxyl group-containing group, which is represented by the following average structural formula, bonded directly to a silicon atom via an (n + 1) -valent functional group (n is a number of 1 or more), A structure having a functional group selected from a silicon atom-containing hydrolyzable group or a metal salt derivative thereof, and the silicon atom further bonded to an oxygen atom (—O—) in another siloxane unit. Having an organosilicon compound.
(R^M ₃SiO_1/2)_a(R^D ₂SiO_2/2)_b(R^TSiO_3/2)_c(SiO_4/2)_d
Where R^M, R^DAnd R^TAre each independently
Monovalent hydrocarbon group, hydrogen atom, hydroxyl group, alkoxy group, a highly polar functional group bonded to a silicon atom via a (n + 1) -valent functional group represented by -Z- (Q) n or containing a hydroxyl group Group, a group having a functional group (Q) selected from a silicon atom-containing hydrolyzable group or a metal salt derivative thereof, or a divalent functional group bonded to the Si atom of another siloxane unit. Here, the monovalent hydrocarbon group is preferably independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 22 carbon atoms, or an aralkyl group. Linear, branched or cyclic alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, pentyl, neopentyl, cyclopentyl, hexyl; vinyl group, propenyl And alkenyl groups such as butyl, pentyl and hexenyl; phenyl and naphthyl. Industrially preferably, the monovalent hydrocarbon group is a methyl group, a vinyl group, a hexenyl group, a phenyl group or a naphthyl group. Examples of the divalent functional group bonded to the Si atom of another siloxane unit include an alkylene group having 2 to 20 carbon atoms or an aralkylene group having 8 to 22 carbon atoms. All R to give an organosilicon compound with a refractive index of 1.55 or higher^M, R^DAnd R^TAmong them, at least 50 mol% of those which are monovalent hydrocarbon groups are phenyl groups or naphthyl groups, and preferably at least 60 mol% of those which are monovalent hydrocarbon groups are phenyl groups or naphthyl groups. It is desirable.
In the formula, a to d are each 0 or a positive number, and a + b + c + d is a number in the range of 2 to 1000. Here, a + b + c + d is preferably 2 to 500, and more preferably 2 to 100. Further, when the surface of the optical fine member is used for post-treatment for the purpose of improving the dispersibility, a + b + c + d is more preferably 3 to 500, and further preferably 5 to 200, A range of 7 to 100 is particularly preferable. At that time, the number (x) of silicon atoms having the functional group (Q) in the average structural formula (excluding the silicon atom in the functional group (Q)) is 1/3 of the a + b + c + d. The number is preferably the following number, from the viewpoint of surface modification, more preferably a number of 1/5 or less, further preferably a number of 1/10 or less, and a number of 1/20 or less. It is particularly preferred.
All R^M, R^DAnd R^TAmong them, at least one is selected from a highly polar functional group, a hydroxyl group-containing group, a silicon atom-containing hydrolyzable group, or a metal salt derivative thereof bonded to a silicon atom via an (n + 1) -valent functional group. It is a group having a functional group (Q). The functional group can modify the surface properties by interacting with the surface of the thermally conductive filler or other optical material. Such interaction with the surface is an interaction or bonding reaction with the material surface derived from the polarity of the functional group, formation of a hydrogen bond derived from the terminal hydroxyl group, or a bonding reaction with the material surface by a hydrolyzable functional group. Even if it is used in a small amount, there is an advantage that an excellent surface modification effect is realized. In particular, the use of an organosilicon compound having such a functional group (Q) can improve the dispersibility in a matrix material by modifying the surface of a thermally conductive filler or the like. Since itself has a high refractive index, there is an advantage that the refractive index of the matrix material can be maintained at a high refractive index of 1.55 or more.
In the formula, -Z- is a (n + 1) -valent functional group, and in the functional group, a heteroatom selected from nitrogen, oxygen, phosphorus, and sulfur, a bivalent or higher arylene group, and a bivalent or higher alkenylene group A linear or branched alkylene group which may contain a divalent or higher alkynylene group, a (poly) siloxane unit, a silalkylene unit, etc., and a silicon atom or a highly polar functional group in the alkylene part or a part other than the alkylene part It is preferably a divalent or higher valent hydrocarbon group to which a functional group (Q) selected from a group, a hydroxyl group-containing group, a silicon atom-containing hydrolyzable group, or a metal salt derivative thereof is bonded. The (n + 1) -valent functional group is preferably a divalent to tetravalent functional group, and particularly preferably a divalent functional group. -Z- is most preferably an alkylene group having 2 to 20 carbon atoms.
The above Q is a functional group selected from a highly polar functional group, a hydroxyl group-containing group, a silicon atom-containing hydrolyzable group, or a metal salt derivative thereof.
The highly polar functional group is specifically a polar functional group containing a heteroatom (O, S, N, P, etc.), and a reactive functional group (including a hydrophilic group) on the substrate surface such as a thermally conductive filler. ) To bond or orient the organosilicon compound to the substrate surface and contribute to surface modification. Such highly polar functional groups include polyoxyalkylene groups, cyano groups, amino groups, imino groups, quaternary ammonium groups, carboxyl groups, ester groups, acyl groups, carbonyl groups, thiol groups, thioether groups, sulfone groups, sulfuric acid groups Examples of such functional groups include a hydrogen group, a sulfonyl group, an aldehyde group, an epoxy group, an amide group, a urea group, an isocyanate group, a phosphoric acid group, an oxyphosphoric acid group, and a carboxylic acid anhydride group. Preferably, these highly polar functional groups are amines, carboxylic acids, esters, amides, amino acids, peptides, organophosphorus compounds, sulfonic acids, thiocarboxylic acids, aldehydes, epoxy compounds, isocyanate compounds. , A functional group derived from a carboxylic acid anhydride.
A hydroxyl group-containing group is a hydrophilic functional group having a silanol group, an alcoholic hydroxyl group, a phenolic hydroxyl group or a polyether hydroxyl group, and dehydrates and condenses with the surface of a thermally conductive filler or the like, or forms one or more hydrogen bonds. By doing so, the organosilicon compound is bonded or oriented to the surface of the base material, thereby contributing to surface modification. Specific examples include a silanol group bonded to a silicon atom, a monovalent or polyhydric alcoholic hydroxyl group, a sugar alcoholic hydroxyl group, a phenolic hydroxyl group, and a polyoxyalkylene group having an OH group at the terminal. Preferably, these are functional groups derived from hydroxysilanes, mono- or polyhydric alcohols, phenols, polyether compounds, (poly) glycerin compounds, (poly) glycidyl ether compounds, hydrophilic saccharides. It is a group.
The silicon atom-containing hydrolyzable group is a functional group having one or more hydrolyzable groups bonded to a silicon atom, and is a monovalent hydrolyzable atom (silanol group by reacting with water directly bonded to a silicon atom). As long as it is a silyl group having at least one of a monovalent hydrolyzable group directly bonded to a silicon atom (a group that generates a silanol group by reacting with water). Such a silicon atom-containing hydrolyzable group is hydrolyzed to produce a silanol group, and this silanol group undergoes dehydration condensation with the substrate surface (M) such as a thermally conductive filler, and thus Si-O- A chemical bond of M (substrate surface) is formed. These silicon atom-containing hydrolyzable groups may be present alone or in combination of two or more in the organosilicon compound of the present invention, and when two or more exist, they may be the same or different. Also good.
Preferably, the silicon atom-containing hydrolyzable group is -SiR.⁵ _fX_3-fThe silicon atom containing hydrolyzable group represented by these can be illustrated. Where R⁵Is an alkyl group or an aryl group, and X is a hydrolyzable group selected from an alkoxy group, an aryloxy group, an alkenoxy group, an acyloxy group, an oxime group, an amino group, an amide group, a mercapto group, an aminoxy group and a halogen atom. Yes, and f is a number from 0 to 2. More specifically, X represents an alkoxy group such as a methoxy group, an ethoxy group, or an isopropoxy group; an alkenoxy group such as an isopropenoxy group; an acyloxy group such as an acetoxy group or a benzoyloxy group; an oxime group such as a methylethyl ketoxime group; An amino group such as a diethylamino group; an amide group such as an N-ethylacetamide group; a mercapto group; a hydrolyzable group selected from an aminoxy group and a halogen atom; an alkoxy group having 1 to 4 carbon atoms; It is preferably a propenoxy group or chlorine.
Also, R⁵Is preferably a methyl group or a phenyl group. Specific examples of these silicon atom-containing hydrolyzable groups include, but are not limited to, a trichlorosilyl group, a trimethoxysilyl group, a triethoxysilyl group, a methyldimethoxysilyl group, and a dimethylmethoxysilyl group. It is not a thing.
The metal salt derivatives of the above highly polar functional groups, hydroxyl group-containing groups, silicon atom-containing hydrolyzable groups are organic acid groups such as alcoholic hydroxyl groups and carboxyl groups, -OH groups such as silanol groups, phosphate groups, and sulfone groups. Is a functional group that forms a salt structure with a metal. Particularly, an alkali metal salt such as sodium, an alkaline earth metal salt such as magnesium, and an aluminum salt are preferably exemplified. In these metal salt derivatives, —O in the functional group⁻The portion electrostatically interacts with the surface of the substrate such as a thermally conductive filler or forms a hydrogen bond to bond or orient the organosilicon compound to the surface of the substrate to improve the surface. Contribute.
Particularly preferably, the functional group (Q) is a carboxyl group, an aldehyde group, a phosphate group, a thiol group, a sulfo group, an alcoholic hydroxyl group, a phenolic hydroxyl group, an amino group, an ester group, an amide group, or a polyoxyalkylene group. , -SiR⁵ _fX_3-fA silicon atom-containing hydrolyzable group represented by the formula:⁵Is an alkyl group or an aryl group, X is a hydrolyzable group selected from an alkoxy group, an aryloxy group, an alkenoxy group, an acyloxy group, a ketoximate group and a halogen atom, and f is a number of 0-2. ) Or a metal salt derivative thereof. In particular, the dispersibility of the organosilicon compound according to the present invention on the surface of one or more base materials selected from thermally conductive fillers, phosphor fine particles, metal oxide fine particles, metal fine particles, nanocrystal structures and quantum dots. When it is used for post-treatment for the purpose of improvement of the carboxyl group, a carboxyl group, a monohydric or polyhydric alcoholic hydroxyl group, a polyoxyalkylene group, -SiR⁵ _fX_3-fA silicon atom-containing hydrolyzable group represented by the formula is preferably used.
When the organosilicon compound has one or more condensation-reactive functional groups or hydrosilylation-reactive functional groups in the molecule, it can be used as a whole or a part of the main component of the curable composition as desired. Specifically, as the curable thermally conductive composition, the above-mentioned organosilicon compound having one or more condensation-reactive functional groups or hydrosilylation-reactive functional groups in the molecule, and reactive silicone as a crosslinking agent After the method of adding the substrate and the curing reaction catalyst and treating the surface of the thermally conductive filler in-situ (integral blend method), the entire composition can be cured. In particular, since the organosilicon compound according to the present invention has excellent blending stability with respect to the silicone-based material, the above curing reaction results in excellent dispersibility and thermal stability of the substrate in the cured product, and is uniform throughout. There is an advantage that a thermally conductive cured product having a high refractive index can be provided.
For example, the substrate, the organosilicon compound having one or more alkenyl groups or acyloxy groups in the molecule, the organopolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule, and the catalyst for hydrosilylation reaction are uniformly formed. A preferred embodiment of the present invention is to prepare a thermally conductive composition containing a substrate surface-treated with the organosilicon compound according to the present invention by mixing with, and curing the composition by heating or the like. Is included.
The organic silicon compound according to the present invention as described above essentially comprises a linear or branched siloxane bond or silalkylene bond represented by the following structural formulas (3-1) to (3-3). Has a hydrophobic main chain siloxane structure, and includes a side chain (including a structure branched through a silalkylene bond) or a terminal silicon atom via an (n + 1) -valent functional group or directly to a silicon atom. Examples thereof include organic silicon compounds having a functional group (Q) selected from a bonded highly polar functional group, hydroxyl group-containing group, silicon atom-containing hydrolyzable group, or a metal salt derivative thereof.

In the above formula, -ZQ is a group as described above, and R¹⁰Are each independently a methyl group, a phenyl group or a naphthyl group;¹¹Are each independently a monovalent functional group selected from a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 22 carbon atoms, a phenyl group, a naphthyl group and a group represented by -ZQ. is there.
In formula (3-1), m1 and m2 are each a number of 1 or more, m1 + m2 is preferably a number in the range of 2 to 400, m1 is a number in the range of 2 to 200, and m2 is 1 A number in the range of ~ 100 is particularly preferred. In the formula (3-1), r is a number in the range of 1 to 20, and preferably a number in the range of 2 to 12. In addition, for the purpose of improving the compounding stability to the hydrosilylation reaction curable silicone resin, R¹¹It is particularly preferable that at least one of the functional groups represented by the above is an alkenyl group having 2 to 22 carbon atoms or a hydrogen atom. Furthermore, in order to increase the refractive index of the organosilicon compound, all R¹⁰And R¹¹It is preferable that at least 50 mol% of these is a phenyl group or a naphthyl group. The number of silicon atoms bonded to the group represented by -ZQ is the number of silicon atoms in the organosilicon compound represented by formula (3-1) (excluding the silicon atom in the functional group (Q)). ) Is preferably 1/3 or less, and more preferably 1/5 or less from the viewpoint of surface modification of the substrate.
In Formula (3-2), m3 and m4 are each a number of 0 or more, m3 + m4 is preferably a number in the range of 0 to 400, m3 is a number in the range of 2 to 300, and m4 is 0. A number in the range of ~ 100 is particularly preferred. In addition, for the purpose of improving the compounding stability to the hydrosilylation reaction curable silicone resin, R¹¹It is particularly preferable that at least one of the functional groups represented by the above is an alkenyl group having 2 to 22 carbon atoms or a hydrogen atom. Furthermore, in order to increase the refractive index of the organosilicon compound, all R¹⁰And R¹¹It is preferable that at least 50 mol% of these is a phenyl group or a naphthyl group. The number of silicon atoms bonded to the group represented by -ZQ is the number of silicon atoms in the organosilicon compound represented by the formula (3-2) (excluding the silicon atom in the functional group (Q)). ) Is preferably 1/3 or less, and more preferably 1/5 or less from the viewpoint of surface modification of the substrate.
In Formula (3-3), m5 is a number of 0 or more, m6 is a number of 1 or more, m5 + m6 is preferably a number in the range of 1 to 400, and m5 is a number in the range of 0 to 300. It is particularly preferred that m4 is a number in the range of 1-10. In addition, for the purpose of improving the compounding stability to the hydrosilylation reaction curable silicone resin, R¹¹It is particularly preferable that at least one of the functional groups represented by the above is an alkenyl group having 2 to 22 carbon atoms or a hydrogen atom. Furthermore, in order to increase the refractive index of the organosilicon compound, all R¹⁰And R¹¹It is preferable that at least 50 mol% of these is a phenyl group or a naphthyl group. The number of silicon atoms bonded to the group represented by -ZQ is the number of silicon atoms in the organosilicon compound represented by formula (3-3) (excluding the silicon atom in the functional group (Q)). ) Is preferably 1/3 or less, and more preferably 1/5 or less from the viewpoint of surface modification of the substrate.
The matrix material composed of the organosilicon compound represented by (A1-3) or a cured product obtained by curing the same preferably has a refractive index of 1.550 to 1.750 at 25 ° C. The range of 1.560 to 1.650 is preferable. In particular, the organosilicon compound represented by (A1-2) has a high refractive index of 1.550 to 1.650 because 50 mol% or more of monovalent hydrocarbon groups bonded to silicon atoms are phenyl groups or naphthyl groups. Rate matrix material can be obtained. The organosilicon compound represented by the above (A1-3) having a high refractive index is particularly represented by the structural formulas (3-1) to (3-3), and in particular, Q is trialkoxy. Particularly preferred are those having a silyl group and Z being an alkylene group having 2 to 12 carbon atoms. In that case, all R¹⁰And R¹¹50 to 80 mol% of the above is a phenyl group or a naphthyl group, and R¹¹It is particularly preferable that at least one of the functional groups represented by the above is an alkenyl group having 2 to 22 carbon atoms or a hydrogen atom.
Here, when the component (A) is a matrix material composed of a cured product obtained by hydrosilylation reaction, the refractive index at 25 ° C. of the cured product comprising the component (A1-3) and the crosslinking agent is 1.550 or more. It is necessary to be. Here, as the component (A1-3), an uncured material having a refractive index of 1.550 or more can be used, but a matrix made of an organosilicon compound obtained by a curing reaction by selecting a crosslinking agent or the like. When the refractive index of the material increases from before the curing, a component having a refractive index of less than 1.550, for example, a component having a refractive index of 1.530 or more may be used as the component (A1-3). Further, when a component having a refractive index of less than 1.550 is used as the component (A1-3), at least one hydrosilylation reactive functional group, at least one phenyl, or a condensed polycycle is used as a crosslinking agent. It is particularly desirable to use those containing an aromatic group or the like in the molecule. At that time, the component (A1-3) is more preferably in the uncured state and has a refractive index close to 1.550, and the refractive index is 1.535 or more, more preferably 1.540 or more. preferable. Further, the refractive index of the cured product obtained by using the component (A1-3) is preferably 1.550 to 1.750, particularly in the range of 1.560 to 1.650. Preferably there is.
The organosilicon compound as component (A) preferably contains one or more of the organosilicon compounds represented by the above (A1-1) to (A1-3), but is cured by a hydrosilylation reaction if desired. From the viewpoint, (A2) organopolysiloxane having at least two alkenyl groups in one molecule, (A3) organopolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, or a mixture thereof. It is preferable to contain. The component (A2) or the component (A3) preferably has a refractive index of 1.550 or more, but can be used even if the refractive index is less than 1.550. However, a mixture obtained by mixing these with an organosilicon compound having a refractive index of 1.550 or more or a cured product obtained by curing the composition contains the component (A) which is the matrix material of the present invention as a whole. Constitute. Therefore, the refractive index at 25 ° C. of the cured product obtained by reacting the mixture or the mixture is required to be 1.550 or more, preferably, the refractive index is 1.550 to 1.750, The refractive index is more preferably 1.555 to 1.680, and most preferably the refractive index is in the range of 1.560 to 1.650.
Component (A2) is an organopolysiloxane having at least two alkenyl groups in one molecule, and is not particularly limited. Examples of the alkenyl group in component (A2) include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group, and a vinyl group or a hexenyl group is preferable. Examples of the group bonded to the silicon atom other than the alkenyl group in the component (A2) include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group; a phenyl group, a tolyl group, An aryl group such as a xylyl group and a naphthyl group; an aralkyl group such as a benzyl group and a phenethyl group; and a halogenated alkyl group such as a chloromethyl group, a 3-chloropropyl group and a 3,3,3-trifluoropropyl group, Preferably, they are a methyl group and a phenyl group. Examples of the molecular structure of such component (A2) include linear, branched, cyclic, network, and partially branched linear.
Examples of such an organopolysiloxane of component (A2) include a trimethylsiloxy group-capped dimethylsiloxane / methylvinylsiloxane copolymer at both ends of a molecular chain, a trimethylsiloxy group-capped methylvinylpolysiloxane at both ends of a molecular chain, and trimethyl at both ends of a molecular chain. Siloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both ends of the molecular chain, dimethylvinylsiloxy group-blocked methylvinylpolysiloxane at both ends of the molecular chain, dimethylvinyl at both ends of the molecular chain Siloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer, both ends of the molecular chain dimethylvinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, General formula: R '₃SiO_1/2And a siloxane unit represented by the general formula: R ′₂R ″ SiO_1/2A siloxane unit represented by the formula: SiO_4/2An organopolysiloxane copolymer comprising a siloxane unit represented by the general formula: R '₂R ″ SiO_1/2A siloxane unit represented by the formula: SiO_4/2An organopolysiloxane copolymer comprising siloxane units represented by the general formula: R′R ″ SiO_2/2A siloxane unit represented by the formula: R′SiO_3/2A siloxane unit represented by the general formula: R ″ SiO_3/2And a mixture of two or more of these organopolysiloxanes. R ′ in the formula represents an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or a heptyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, or a naphthyl group; An aralkyl group such as a benzyl group or a phenethyl group; a halogenated alkyl group such as a chloromethyl group, a 3-chloropropyl group, or a 3,3,3-trifluoropropyl group. R ″ in the formula is an alkenyl group, and examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group.
The organopolysiloxane of component (A3) is not particularly limited as long as it has silicon-bonded hydrogen atoms. Examples of the bonding position of the silicon atom-bonded hydrogen atom in component (A3) include molecular chain terminals and / or molecular chain side chains. Other groups bonded to the silicon atom in the component (A3) include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group; phenyl group, tolyl group, xylyl group And aryl groups such as naphthyl group; aralkyl groups such as benzyl group and phenethyl group; and halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group and 3,3,3-trifluoropropyl group, , Methyl group and phenyl group. Examples of the molecular structure of such component (A3) include linear, branched, cyclic, network, and partially branched linear.
Examples of such an organopolysiloxane of component (A3) include trimethylsiloxy group-capped methylhydrogen polysiloxane with molecular chain at both ends, trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer with both molecular chains, Terminal trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer, molecular chain both ends dimethylhydrogensiloxy group-blocked dimethylpolysiloxane, molecular chain both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylphenylsiloxane Copolymer, dimethylhydrogensiloxy group-blocked methylphenylpolysiloxane with molecular chain at both ends, general formula: R ′₃SiO_1/2And a siloxane unit represented by the general formula: R ′₂HSiO_1/2A siloxane unit represented by the formula: SiO_4/2An organopolysiloxane copolymer comprising a siloxane unit represented by the general formula: R '₂HSiO_1/2A siloxane unit represented by the formula: SiO_4/2An organopolysiloxane copolymer comprising a siloxane unit represented by the general formula: R'HSiO_2/2A siloxane unit represented by the general formula: R′SiO_3/2A siloxane unit represented by the formula: HSiO_3/2And a mixture of two or more of these organopolysiloxanes. In the formula, R ′ is the same group as described above.
The refractive index of the mixture containing component (A2) or component (A3) or a cured product obtained by curing the mixture needs to be 1.55 or more, and component (A2) or component (A3) It is particularly preferable to have one or more phenyl groups therein. Further, from the viewpoint of increasing the refractive index of the matrix material of the thermally conductive composition according to the present invention, the component (A2) or the component (A3) contains one or more phenyl groups, condensed polycyclic aromatic groups, etc. in the molecule. It is particularly preferable to have a plurality of phenyl groups or naphthyl groups in the molecule.
The matrix material of the thermally conductive composition according to the present invention is not necessarily limited to the curable composition or the cured product obtained by reacting it, but a component (A2) or a mixture containing the component (A3). In the case of curing by hydrosilylation reaction, component (C) preferably contains a hydrosilylation reaction catalyst.
Examples of the hydrosilylation reaction catalyst include a platinum-based catalyst, a rhodium-based catalyst, and a palladium-based catalyst, and a platinum-based catalyst is preferable because it can significantly accelerate the curing of the composition. Examples of the platinum-based catalyst include platinum fine powder, chloroplatinic acid, an alcohol solution of chloroplatinic acid, a platinum-alkenylsiloxane complex, a platinum-olefin complex, and a platinum-carbonyl complex, preferably a platinum-alkenylsiloxane complex. is there.
When the heat conductive composition according to the present invention is designed as a hydrosilylation reaction curable composition, the silicon-bonded hydrogen atoms are in a molar ratio of 0.1 to 5 with respect to the alkenyl groups in the composition. The amount is within the range, and particularly preferably within the range of 0.5-2.
In the hydrosilylation reaction curable composition, the content of the hydrosilylation reaction catalyst as the component (C) is not particularly limited as long as it is an amount that promotes the curing of the composition. Specifically, The amount by which the catalytic metal in the component (C) is in the range of 0.01 to 500 ppm, more preferably in the range of 0.01 to 100 ppm, in particular, by mass unit with respect to the above composition, The amount is preferably in the range of 0.01 to 50 ppm.
Component (B) is a thermally conductive filler composed of a single component or a plurality of components, and is excellent in a thermally conductive composition according to the present invention, a cured product obtained by curing it, or a thermally conductive material composed thereof. It is a component that imparts heat conduction characteristics. As such a heat conductive filler, a filler made of an inorganic substance or an organic substance can be used. In particular, it is preferable to use an inorganic filler because of its high thermal conductivity, but it is preferable not to use a metallic inorganic filler that does not transmit light, carbon black, graphite, or the like for applications that require transparency. .
In the present invention, as the component (A), an organic silicon compound which is a matrix material having a refractive index of 1.55 or more is used, whereby the composition or its cured product is excellent in transparency and thermal conductivity, and has a high refractive index. Therefore, the inorganic filler as the thermally conductive filler preferably has a refractive index of 1.500 to 1.800. It is preferable to use an inorganic filler of 550 to 1.700.
From the viewpoint of adjusting the refractive index for heat conductivity and transparency, the heat conductive filler suitable for the heat conductive composition according to the present invention is a metal hydroxide, a metal carbonate, and a water of metal oxide. One or more kinds of thermally conductive fillers selected from Japanese. In particular, in the range of the refractive index of 1.550 to 1.700, it is easy to design a small difference in refractive index from the matrix material made of an organosilicon compound having a refractive index of 1.550 or more according to the present invention. Particularly preferred is the use of one or more thermally conductive fillers selected from aluminum hydroxide, magnesium hydroxide, magnesium carbonate, and boehmite. These thermally conductive fillers have a refractive index in the range of 1.570 to 1.650, and can minimize the difference in refractive index with respect to the high refractive index matrix material made of the organosilicon compound, A heat conductive composition that maintains a high refractive index and is excellent in transparency and heat conductivity can be provided. Metal hydroxides such as aluminum hydroxide are expected to have a thermal conductivity of about 8 W / m · K, and by blending them, the thermal conductivity of the composition can be sufficiently increased. In addition, metal oxides such as alumina, zinc oxide and magnesium oxide; metal nitrides such as boron nitride and aluminum nitride; metal carbides such as boron carbide and silicon carbide; aluminum, copper, It is also possible to use a metal such as nickel in combination.
The refractive index of the thermally conductive filler is preferably as the anisotropy is small, and more preferably, there is no anisotropy of the refractive index, that is, the refractive index is isotropic. If the refractive index of the thermally conductive filler is isotropic, the matrix material composed of the organosilicon compound as the component (A) and the refractive index of the thermally conductive filler regardless of the direction of the thermally conductive filler. By reducing the difference, it becomes easy to further improve the transparency of the thermally conductive composition.
The shape of the heat conductive filler is not particularly limited, and includes any shape such as spherical shape, scale shape, polyhedron shape, irregular shape, rod shape, plate shape, spindle shape, flake shape, fiber shape, and needle shape. May be used. The shape of the thermally conductive filler to be added need not be only one type, and may be a mixture of two or more types.
The heat conductive filler may have a surface treated with a surface treatment agent. Examples of the surface treatment agent include, but are not limited to, a silane coupling agent (alkoxysilane or alkylalkoxysilane, etc.), silazane, fatty acid, fatty acid ester, alcohol, and alkylthiol. Known surface treatment agents and surface treatment methods can be appropriately selected according to the purpose of modification such as chemical properties, water resistance, and heat resistance. In particular, when a hydrophobized filler is used, the filler can be dispersed at a high filling rate in the organopolysiloxane composition, and there is an advantage that the increase in the viscosity of the composition is suppressed and the handleability is improved. These surface treatment agents may be used alone or in combination of two or more according to the purpose.
As the surface treatment agent used for hydrophobizing the thermally conductive filler, at least one surface treatment agent selected from the group consisting of an organic titanium compound, an organic silicon compound, an organic zirconium compound, an organic aluminum compound, and an organic phosphorus compound is used. It is preferable to do. In particular, examples of the organosilicon compound include low molecular weight organosilicon compounds such as alkoxysilane, alkylalkoxysilane, silazane, siloxane, and carbosilane, and organosilicon polymers or oligomers such as polysilane, polysilazane, polysiloxane, and polycarbosilane. The
The average particle diameter of the heat conductive filler is not limited, but is preferably 0.1 μm or more. Thermally conductive fillers with a small average particle size have a large specific surface area, so the viscosity of the blended composition is likely to be higher compared to thermal conductive fillers with a large average particle size, and the highly conductive filler is highly filled. It becomes difficult to do. More preferably, the average particle size of the thermally conductive filler is 1 μm or more, the average particle size is preferably in the range of 1 to 100 μm, and particularly preferably in the range of 1 to 50 μm. Thermally conductive fillers can be used in combination with those having two or more types of particle sizes depending on the purpose. For example, when two kinds of particle diameters are combined, it is preferable that one particle diameter is 1 to 10 μm and the other particle diameter is 5 to 100 μm. In particular, it is preferable to combine a heat conductive filler with a large average particle size and a heat conductive filler with a small average particle size in a ratio according to the closest packing theoretical distribution curve, which improves the packing efficiency and lowers the viscosity. In addition, there is an advantage that high heat conduction is possible.
From the viewpoint of transparency, it is preferable that the difference in refractive index between the matrix material composed of component (A) and the thermal conductive filler (B) is 0.05 or less in absolute value. The value is more preferably 0.03 or less, and the absolute value is most preferably in the range of 0.00 to 0.02. If it does in this way, it can suppress that a heat conductive filler scatters light in a matrix material, and can realize a transparent heat conductive composition with a high refractive index and high transparency. And this transparent heat conductive composition or hardened | cured material can be used as a heat conductive material excellent in refractive index, transparency, and heat conductivity.
The thermally conductive composition or cured product thereof according to the present invention is excellent in transparency, and can easily obtain a light transmittance of visible light (wavelength 600 nm) at a thickness of 0.2 mm of 65% or more. it can. Preferably, the light transmittance at a wavelength of 600 nm is 75% or more, and particularly preferably 80% or more. When the difference in refractive index between the matrix material comprising the component (A) and the thermal conductive filler (B) is in the range of 0.00 to 0.02 in absolute value, the light transmittance can be relatively easily achieved. Is extremely useful in that a 90% or higher thermal conductive composition or a cured product thereof can be obtained. Moreover, since the temperature dependence coefficient of a refractive index differs between the organosilicon compound used in the present invention and the thermally conductive filler, the refractive index difference differs depending on the measurement temperature, and the transmittance also differs. In order to improve the transmittance at a desired temperature, it is possible to take a method of reducing the difference in refractive index at the desired temperature.
The thermally conductive composition according to the present invention comprises 10 to 2000 parts by mass of component (B) with respect to 100 parts by mass of component (A), and preferably 20 parts of component (B). It is in the range of ~ 1500 parts by mass, more preferably in the range of 25 to 1000 parts by mass, and particularly preferably in the range of 30 to 750 parts by mass. When the content of the component (B) is less than the lower limit, the thermal conductivity is not sufficient, and in particular, thermal conductivity of 0.2 W / m · K or more may not be obtained. On the other hand, when the content of the component (B) exceeds the above upper limit, the viscosity of the heat conductive composition is increased, and not only handling and molding become difficult, but also bubbles are easily introduced due to the increase in viscosity, and transparency. May be damaged. When the content of the component (B) is within the range of the present invention, in addition to high refractive index and high transparency, a composition having excellent heat conduction characteristics of 0.3 to 3.0 W / m · K or A thermally conductive cured product comprising the same can be easily obtained.
The transparent thermal conductive composition according to the present invention may contain an adhesion-imparting agent for improving the adhesion. This adhesion-imparting agent includes alkoxysilyl substitution in which 1 to 2 allyl groups of triallyl isocyanurate, trimethacryl isocyanurate and triallyl isocyanurate are added with 1 to 2 alkoxysilyl groups such as trimethoxysilyl group. In addition to triallyl isocyanurate and a siloxane modification product (derivative) that is a hydrolysis-condensation product thereof, an organosilicon compound having at least one alkoxy group bonded to a silicon atom in one molecule is preferable. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a methoxyethoxy group, and a methoxy group is particularly preferable. The group other than the alkoxy group bonded to the silicon atom of the organosilicon compound includes a substituted or unsubstituted monovalent hydrocarbon group such as an alkyl group, an alkenyl group, an aryl group, an aralkyl group, and a halogenated alkyl group; 3 -Glycidoxyalkyl groups such as glycidoxypropyl group and 4-glycidoxybutyl group; epoxies such as 2- (3,4-epoxycyclohexyl) ethyl group and 3- (3,4-epoxycyclohexyl) propyl group Cyclohexylalkyl group; epoxy group-containing monovalent organic group such as oxiranylalkyl group such as 4-oxiranylbutyl group and 8-oxiranyloctyl group; acrylic group-containing monovalent organic group such as 3-methacryloxypropyl group Group; a hydrogen atom is exemplified. This organosilicon compound preferably has a silicon atom-bonded alkenyl group or a silicon atom-bonded hydrogen atom. Moreover, since it can provide favorable adhesiveness to various types of substrates, the organosilicon compound preferably has at least one epoxy group-containing monovalent organic group in one molecule. Examples of such organosilicon compounds include organosilane compounds, organosiloxane oligomers, and alkyl silicates. Examples of the molecular structure of the organosiloxane oligomer or alkyl silicate include linear, partially branched linear, branched, cyclic, and network, particularly linear, branched, and network. Preferably there is. Examples of such organosilicon compounds include silane compounds such as 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 3-methacryloxypropyltrimethoxysilane; A siloxane compound having at least one silicon atom-bonded alkenyl group or silicon atom-bonded hydrogen atom and silicon atom-bonded alkoxy group, and a silane compound or siloxane compound having at least one silicon atom-bonded alkoxy group and silicon in one molecule. Examples thereof include a mixture of a siloxane compound having at least one atom-bonded hydroxy group and at least one silicon atom-bonded alkenyl group, methyl polysilicate, ethyl polysilicate, and epoxy group-containing ethyl polysilicate.
In the present composition, the content of this adhesion-imparting agent is not limited, but when the transparent thermally conductive composition according to the present invention is cured by a thermally conductive grease or hydrosilylation reaction, it is based on 100 parts by mass of the entire composition. Is preferably in the range of 0.01 to 10 parts by mass.
In addition, when the transparent heat conductive composition according to the present invention is cured by a hydrosilylation reaction, 2-methyl-3-butyn-2-ol, 3,5-dimethyl- Alkyne alcohols such as 1-hexyn-3-ol and 2-phenyl-3-butyn-2-ol; 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne and the like 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenyl You may contain reaction inhibitors, such as a cyclotetrasiloxane and a benzotriazole.
In the present composition, the content of the reaction inhibitor is not limited, but is preferably in the range of 0.0001 to 5 parts by mass with respect to 100 parts by mass of the entire composition.
When the transparent heat conductive composition according to the present invention is cured by a hydrosilylation reaction, it is extremely useful for LED element sealing, particularly for blue LED, white LED, ultraviolet LED and the like. Therefore, various known phosphor powders can be added as long as the object of the present invention is not violated. Specifically, one or more optical fine members selected from phosphor fine particles, metal fine particles, nanocrystal structures, and quantum dots can be contained. In addition, other metal oxide fine particles may be included as long as the object of the present invention is not adversely affected, but a large amount of metal oxide fine particles having a refractive index greatly different from that of the matrix material or the heat conductive filler is used. When it mix | blends, since transparency and a refractive index may be impaired especially, it is unpreferable. In addition, it is particularly preferable that a part or all of these optical fine members have been surface-treated with the above component (A1-3) or a silane coupling agent.
In particular, the composition of the present invention preferably contains phosphor fine particles when the transparent heat conductive composition according to the present invention is cured by a hydrosilylation reaction. Examples of the phosphor include oxide phosphors, oxynitride phosphors, nitride phosphors, sulfide phosphors, and oxysulfide phosphors that are widely used in light emitting diodes (LEDs). Examples thereof include yellow, red, green, and blue light emitting phosphors. Examples of oxide-based phosphors include yttrium, aluminum, and garnet-based YAG-based green to yellow light-emitting phosphors containing cerium ions, terbium, aluminum, garnet-based TAG-based yellow light-emitting phosphors including cerium ions, and Examples include silicate green to yellow light emitting phosphors containing cerium and europium ions. Examples of the oxynitride phosphor include silicon, aluminum, oxygen, and nitrogen-based sialon-based red to green light-emitting phosphors containing europium ions. Examples of nitride-based phosphors include calcium, strontium, aluminum, silicon, and nitrogen-based casoon-based red light-emitting phosphors containing europium ions. Examples of the sulfide type include ZnS type green coloring phosphors including copper ions and aluminum ions. Examples of oxysulfide phosphors include Y2O2S red light-emitting phosphors containing europium ions. These fluorescent materials may be used singly or as a mixture of two or more.
The transparent heat conductive composition according to the present invention may contain an organic solvent as desired for preparation of heat conductive grease, molding and handling of the curable composition, and the like. The organic solvent is not particularly limited as long as it has a boiling point of 80 to 360 ° C. which disperses or dissolves the organic silicon compound having a refractive index of 1.55 or more as the component (A). For example, toluene, xylene, and isoparaffin are used. Can be mentioned. The boiling point of the volatile solvent is preferably in the range of 260 to 360 ° C. When the boiling point of the volatile solvent is less than the lower limit, volatilization becomes too fast and the viscosity of the composition may increase during the operation. On the other hand, when the boiling point exceeds the upper limit, when the transparent thermally conductive composition is a thermally conductive grease, the solvent tends to remain, and voids may be generated, resulting in deterioration of thermal characteristics.
The heat conductive composition according to the present invention adds a flux component to remove the oxide film present on the surface of the heat conductive filler to be used and improve the characteristics of the heat conductive filler, if desired. Is effective. Flux components can be broadly divided into three types: inorganic, organic, and resinous. Inorganic systems include orthophosphoric acid, hydrochloric acid, hydrobromic acid, hydrofluoric acid, etc., zinc chloride, stannous chloride, ammonium chloride, ammonium fluoride, sodium fluoride, zinc chloride / ammonium chloride = 75 / Inorganic acid type such as 25. Specific examples of organic systems include organic acid systems such as formic acid, acetic acid, oleic acid, stearic acid, adipic acid, lactic acid, and glutamic acid, organic acid salts such as ammonium formate and methylamine lactate, amines such as ethylenediamine, Examples include amine hydrohalides such as methylamine hydrochloride, butylamine hydrobromide, ethylenediamine hydrochloride, triethanolamine hydrochloride, and aniline hydrochloride. Examples of the resin system include rosin and active rosin. The blending amount of the flux is preferably in the range of 0.05 to 40 parts by mass, more preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the component (A) that is the matrix material.
In the thermally conductive composition according to the present invention, additives, fillers, and the like that are usually used in silicone-based compositions can be further used as optional components as long as the object of the present invention is not impaired. For example, BHT, vitamin B, etc. as antioxidants, known discoloration inhibitors, such as organophosphorus discoloration inhibitors, photodegradation inhibitors such as hindered amines, etc., reactive diluents such as vinyl ethers, vinylamides, epoxy Resin, oxetanes, allyl phthalates, vinyl adipate, etc., as a settling inhibitor at high temperatures of thermally conductive fillers, sedimentation or fine powders such as calcined silica, flame retardant improver, thixotropic improver, Process oil or the like may be added as a processability improver.
The heat conductive composition according to the present invention can be easily obtained by uniformly mixing the above-described components using mechanical force. The equipment used for mixing each component is not particularly limited, but homomixer, paddle mixer, Henschel mixer, line mixer, homodisper, propeller stirrer, vacuum kneader, homogenizer, kneader, dissolver, high speed disperser. , Sand mill, roll mill, ball mill, tube mill, conical mill, vibration ball mill, high swing ball mill, jet mill, attritor, dyno mill, GP mill, wet atomizer (made by Sugino Machine, Optimizer, etc.), ultrasonic disperser ( Examples thereof include an ultrasonic homogenizer, a bead mill, a Banbury mixer, a stone mill, and a grindstone grinder.
The heat conductive composition according to the present invention can be used as a heat conductive material in a desired form. In particular, the thermally conductive composition according to the present invention is useful as a thermally conductive grease, a thermally conductive cured product, or a thermally conductive composition having thermal softening properties (= phase change material). explain.
The heat conductive composition according to the present invention is useful as a heat conductive grease having high transparency and high refractive index. Such a thermally conductive grease may be one in which the organosilicon compound as the matrix material is cured by a hydrosilylation reaction or the like, or may be a non-curable mixture, but the organosilicon compound as the matrix material is hydrosilylated. It is preferably an organosilicon compound having a functional group curable by reaction, having a refractive index of 1.550 to 1.750 at 25 ° C., and having an alkenyl group or a silicon atom-bonded hydrogen atom in the molecule It is particularly preferred to contain the organopolysiloxane which is the component (A2) or (A3) which is the crosslinking agent.
The heat conductive grease can take a desired form at the time of coating, but can be cast and formed into a sheet or film. In addition, the thermal conductive composition is applied to the surface of the display or the light source surface of the illumination, or the thermal conductive composition is poured into a gap such as an electronic component including a heating element, and then the thermal conductive composition is cured. Thus, it is possible to form a thermally conductive molded article having excellent transparency and high refractive index. Such a heat conductive member for a semiconductor device is not limited to an optical semiconductor, and can be widely used as, for example, a heat dissipation material for a semiconductor device that requires design or internal visibility.
The thermally conductive composition according to the present invention can be cured by a hydrosilylation reaction or the like to give a thermally conductive cured product having high transparency and a high refractive index. Such a cured product may be one that forms a heat conductive rubber by complete curing, or one that forms a heat conductive gel by semi-curing. Although the curing system is not limited, it is preferable that the organic silicon compound as the matrix material is cured by a hydrosilylation reaction or the like, and has a refractive index of 1.550 to 1.750 at 25 ° C. Thermal conductivity containing an organosilicon compound having a group or a silicon atom-bonded hydrogen atom, the above-mentioned (A2) component or (A3) component organopolysiloxane as the crosslinking agent, the above hydrosilylation reaction catalyst and reaction inhibitor It is preferable that it is an adhesive composition. If desired, the composition may contain an organic solvent.
The curable thermally conductive composition can be cast and formed into a sheet or film like the thermally conductive grease, but it is particularly suitable for use as an optical material for sealing an optical semiconductor element. it can. In particular, the optical semiconductor sealing material formed by curing the thermally conductive composition according to the present invention, and the optical material such as a lens are excellent in transparency and have a high refractive index. There is an advantage that the heat radiation characteristics of the high-brightness optical semiconductor device can be improved. In this case, as a sealing method, a conventional method according to the type of the optical semiconductor is adopted, but the curing condition of the curable thermal conductive composition of the present invention is in a temperature range from room temperature to about 200 ° C. The time range can be from several tens of seconds to several days, but preferably from about 1 minute to about 10 hours in a temperature range of 80 to 180 ° C.
The use of the optical material comprising the thermally conductive composition of the present invention is not particularly limited, and examples thereof include a light emitting diode, a phototransistor, a photodiode, a CCD, a solar cell module, an EPROM, a photocoupler, and the like. Used effectively for diodes.
Moreover, the heat conductive composition of this invention can be shape | molded and used for a sheet form or a film form as above-mentioned. As a method of forming into a sheet form or a film form, the heat conductive composition after mixing may be formed by extrusion molding, calendar molding, roll molding, press molding, or coating after dissolving in a solvent. it can. The thickness of the sheet and film is not particularly limited, but is 0.02 to 2 mm, particularly 0.03 to 1 mm, and preferably 0.1 to 0.4 mm. In addition, a release sheet or the like can be attached before use.
The heat conductive composition of the present invention is also useful as a heat conductive composition (= phase change material) having heat softening properties. Specifically, the heat conductive composition containing the organosilicon compound of the present invention is solid at 25 ° C., and is softened, reduced in viscosity, or melted at least in the range of 40 to 115 ° C. This can be achieved by selecting the organosilicon compound so that is fluidized.
The organosilicon compound which is such a matrix material is not particularly limited, but can be obtained by adding a compound which becomes a liquid when heated in solid or paste form at room temperature to the heat conductive gel obtained by the hydrosilylation reaction. In addition, a resin-structured organopolysiloxane having a condensed polycyclic aromatic group or a condensed polycyclic aromatic group-containing group such as a naphthyl group represented by the above (A1-1) is used as a main component of the matrix material. A heat conductive composition having heat softening properties can be easily obtained. The heat softening point mentioned here is the heat softening point of the heat conductive composition containing the organic compound, and the heat softening point of the organosilicon compound may be 25 ° C. or less.
The thermally conductive composition having heat softening properties according to the present invention is excellent in transparency and has a high refractive index. Therefore, even when used in an optical semiconductor device or the like, the luminous efficiency, luminance, and light extraction efficiency are not impaired. The heat softening heat conductive composition can be interposed between the heat generator and the heat radiator. The heat-softening thermally conductive composition has a low viscosity, softened or melted due to heat generation during operation of an electronic component such as a high-brightness LED, and at least the surface fluidizes, thereby causing the gap between the electronic component and the heat-dissipating component. There is an advantage that the interface contact thermal resistance between the electronic component and the heat dissipating component filled substantially without a gap is reduced, and the heat dissipating efficiency is remarkably improved.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to the following Example. In the following composition formula, Vi represents a vinyl group, Me represents a methyl group, Ph represents a phenyl group, and Np represents a naphthyl group. Moreover, the structure of each organosilicon compound was identified using ¹³ C and ²⁹ Si-NMR. Moreover, the weight average molecular weight and dispersion degree were identified with the polystyrene standard by the gel permeation chromatography.
Hereinafter, methods for measuring the refractive index, transmittance, and thermal conductivity of liquid materials or cured products according to Examples and the like will be described.
[Refractive index of liquid material]
The refractive index of the liquid material was measured at 25 ° C. and 590 nm.
[Refractive index of cured product]
The refractive index of the curable silicone composition was measured using a prism coupler method at 25 ° C. For the measurement, 403 nm, 473 nm, 633 nm, and 847 nm laser light sources were used, and the refractive index at 590 nm was estimated.
[Transmissivity]
The transmittance indicates the transmittance of light having a wavelength of 600 nm at a thickness of 0.2 mm. Unless otherwise specified, the transmittance at 25 ° C. is shown.
[Thermal conductivity]
The thermal conductivity was measured using Thermal Conductive Analyzer TCi (manufactured by C-THERM Technologies).
[Reference Example 1: Synthesis of naphthyl group-containing organopolysiloxane]
Into a reaction vessel, 10 g (40.3 mmol) of 1-naphthyltrimethoxysilane, 4.2 g (13.5 mmol) of 1,3-divinyl-1,3-diphenyldimethyldisiloxane, and 20 g of toluene were added and mixed in advance. Thereafter, 2.2 g (122.1 mmol) of water and 10 g of methanol were added, and 0.069 g (0.46 mmol) of trifluoromethanesulfonic acid was added with stirring, followed by heating under reflux for 2 hours. Then, heating and normal pressure distillation were performed until it became 85 degreeC, and it was made to react at this temperature for 1 hour. Next, 0.06 g (1.1 mmol) of potassium hydroxide was added, and atmospheric pressure distillation was performed until the reaction temperature reached 120 ° C., and the reaction was performed at this temperature for 1 hour. After cooling to room temperature, 0.09 g (1.5 mmol) of acetic acid was added to carry out a neutralization reaction. After the produced salt was filtered off, low-boiling substances were removed from the obtained transparent solution by heating under reduced pressure, and 10.3 g (yield: 90.4) of a colorless transparent viscous liquid having a viscosity exceeding 10,000 Pa · s. %).
As a result of NMR analysis, this viscous liquid has an average unit formula:
(MeViPhSiO _1/2 ) ₄₀ (NpSiO _3/2 ) ₆₀
It was found that the organopolysiloxane represented by The weight average molecular weight (Mw) of this organopolysiloxane was 1,000, the dispersity (Mw / Mn) was 1.08, and the refractive index was 1.622.
[Reference Example 2: Synthesis of polyorganometallosiloxane]
Tetraisopropoxytitanium 49.3 g (0.173 mol), ethanol 15 g, toluene 45 g, and zinc acetate dihydrate 10.01 g (0.046 mol) were mixed, and further diphenyldimethoxysilane 24.1 g (0.099 mol). Was added. Thereafter, a mixture of 11.5 g of 0.1N dilute hydrochloric acid and 64.0 g of ethanol was slowly added dropwise, and after completion of the addition, the mixture was stirred at room temperature for 1 hour. Subsequently, it heated and refluxed for 1 hour. The solvent was distilled off by heating under reduced pressure to obtain 33.5 g (yield 92%) of a colorless solid having a refractive index of 1.670.
When the reaction rate of the alkoxysilyl group of this solid was measured by NMR, it was 99.4 mol%, and TiO _4/2 : ZnO _2/2 : Ph ₂ SiO _2/2 = 0.55: 0.15: 0. It was found to be a polyorganometallosiloxane consisting of 30 (= 1.83: 0.50: 1).
Vinyldimethylsilanol was added to a 50 wt% toluene solution of the polyorganometallosiloxane so as to have the charged composition (molar ratio) shown in Table 1, and heated at 80 ° C. for 3 hours.
Subsequently, polyorganometallosiloxane (1) and (2) shown in Table 1 were prepared by distilling off the solvent under reduced pressure under heating.

[Reference Example 3: Synthesis of Silethylene Silicone (1)]
Average structural formula: ViMe ₂ Si (OSiMePh) ₁₃ (OSiPh ₂ ) ₁₃ OSiMe ₂ Vi Both-end vinyldimethylsiloxy group-blocked phenylmethylsiloxane / diphenylsiloxane copolymer 20 g (4.3 mmol) and platinum and 1, The complex of 3-divinyltetramethyldisiloxane was mixed in such an amount that the amount of platinum metal was 2 ppm by mass relative to the total amount of the reaction mixture. After heating to 90 ° C., 1.21 g (4.3 mmol) of the compound represented by the average structural formula: HMe ₂ SiOSiMe ₂ C ₂ H ₄ Si (OMe) ₃ was added dropwise. After stirring at 100 ° C. for 0.5 hour, a part was sampled and analyzed by IR, and it was found that SiH groups were completely consumed. Low-boiling substances were removed by heating under reduced pressure, and 20.7 g of silethylene silicone (1) having the following average structure was removed.

Obtained as a colorless transparent liquid (yield 97.6%). The refractive index was 1.576.
[Example 1-8: Thermally conductive grease]
(ViPhMeSiO _1/2 ) ₄₀ (NpSiO _3/2 ) ₆₀ , HMe ₂ SiO (Ph ₂ SiO) SiMe ₂ H, and aluminum hydroxide (particles) with the compositions shown in Table 2 (numbers are parts by mass) 30 μm diameter, specific gravity 2.42) or magnesium hydroxide (particle diameter 3 μm, specific gravity 2.36) was uniformly mixed to obtain a grease. Table 2 shows the measurement results of the refractive index of the matrix material of the obtained grease, the refractive index of the filler, the transmittance of the grease, and its thermal conductivity.

[Examples 9-13, Comparative Example 1: Thermally conductive film]
(ViPhMeSiO _1/2 ) ₄₀ (NpSiO _3/2 ) ₆₀ , HMe ₂ SiO (Ph ₂ SiO) SiMe ₂ H, and aluminum hydroxide (particles) with the compositions shown in Table 3 (numbers are parts by mass) A diameter of 30 microns and a specific gravity of 2.42) were mixed uniformly. Next, the platinum 1,3-divinyltetramethyldisiloxane complex was mixed in such an amount that the platinum metal was 2 ppm by mass relative to the solid content, and the curable organopolysiloxane composition according to Example 9-13 was obtained. Prepared. In all the compositions, the molar ratio (= SiH / Vi ratio) of silicon atom-bonded hydrogen atoms to silicon atom-bonded vinyl groups in the composition relating to the hydrosilylation reaction is 1.0.
A curable organopolysiloxane composition according to Comparative Example 1 having the composition shown in Table 3 was prepared in the same manner as in Example 9-13 except that aluminum hydroxide was not added.
These curable organopolysiloxane compositions were heated at 70 ° C. for 1 hour and then heated at 150 ° C. for 2 hours to obtain a film as a cured product of the curable organopolysiloxane composition. Table 3 shows the measurement results of the refractive index of the matrix material, the refractive index of the filler, the transmittance of the film, and the thermal conductivity of the obtained film (cured product). As a result, the film according to the example is excellent in transparency and thermal conductivity, whereas the film of Comparative Example 1 in which no heat-dissipating filler is blended has almost the same light transmittance as that of the film of Example 9. Although it is not, it is clearly inferior in thermal conductivity.

[Example 14: Thermally conductive film exhibiting high transparency at high temperature]
With the composition shown in Table 4, (ViPhMeSiO _1/2 ) ₄₀ (NpSiO _3/2 ) ₆₀ , HMe ₂ SiO (Ph ₂ SiO) SiMe ₂ H, and magnesium hydroxide (particle diameter 3 microns, specific gravity 2.36) Were mixed uniformly. Next, platinum 1,3-divinyltetramethyldisiloxane complex was mixed in such an amount that platinum metal was 2 ppm by mass with respect to the solid content to prepare a curable organopolysiloxane composition. In the composition, the molar ratio (= SiH / Vi ratio) of silicon atom-bonded hydrogen atoms to silicon atom-bonded vinyl groups in the composition related to the hydrosilylation reaction is 1.0.
The curable organopolysiloxane composition was heated at 70 ° C. for 1 hour and then heated at 150 ° C. for 2 hours to obtain a film as a cured product of the curable organopolysiloxane composition. The refractive index (25 ° C.) of the matrix material of the film (cured product), the refractive index of the filler (25 ° C.), and the transmittance and thermal conductivity of the film at 25 ° C., 100 ° C., 150 ° C., and 200 ° C. The results of measuring are shown in Table 4. As shown in Table 4, the transmittance of the film at 200 ° C. reached 96%, and the film is particularly excellent in transparency at high temperatures.

[Example 15: Thermosoftening organopolysiloxane composition]
In the composition shown in Table 5, (ViPhMeSiO _1/2 ) ₄₀ (NpSiO _3/2 ) ₆₀ and boehmite (particle diameter 2 microns, specific gravity 3.07) were mixed uniformly to obtain a thermosoftening organopolysiloxane composition. Prepared. The refractive index (25 ° C.) of the matrix material of the resulting thermosoftening organopolysiloxane composition, the refractive index of the filler (25 ° C.), and the transmittance and thermal conductivity of the composition at 25 ° C. were measured. Further, since the obtained composition has fluidity on the surface at 60 to 80 ° C., in addition to excellent transparency and thermal conductivity, it has a property of flowing by heating.

[Examples 16 and 17: Thermally conductive film using polyorganometallosiloxane]
(ViMe ₂ SiO _1/2 ) ₂₅ (PhSiO _3/2 ) ₇₅ , HMe ₂ SiO (Ph ₂ SiO) _2.5 SiMe ₂ H, and the polyorganometallo obtained in Reference Example 2 with the composition shown in Table 6 After mixing the siloxane, it was diluted with toluene to prepare a 20% solution, and then aluminum hydroxide (particle size 30 microns, specific gravity 2.42) was added. Subsequently, the toluene solution of the curable organopolysiloxane composition was prepared by mixing the platinum 1,3-divinyltetramethyldisiloxane complex in an amount of 2 ppm by mass with respect to the solid content of platinum metal. In the composition, the molar ratio (= SiH / Vi ratio) of silicon atom-bonded hydrogen atoms to silicon atom-bonded vinyl groups in the composition related to the hydrosilylation reaction is 1.0.
The curable organopolysiloxane composition (toluene solution) is heated at 70 ° C. for 1 hour to remove the solvent, and then heated at 150 ° C. for 2 hours to form a cured product of the curable organopolysiloxane composition. Got. Table 6 shows the results of measuring the refractive index (25 ° C.) of the matrix material of the film (cured product), the refractive index of the filler (25 ° C.), and the transmittance and thermal conductivity of the film.

[Example 18-20: Thermally conductive grease using silethylene silicone]
With the composition shown in Table 7, the silethylene silicone (1) obtained in Reference Example 3 and aluminum hydroxide (particle size 30 microns, specific gravity 2.42) were uniformly mixed to obtain a grease. Table 7 shows the measurement results of the refractive index of the matrix material of the obtained grease, the refractive index of the filler, the transmittance of the grease, and its thermal conductivity.

[Example 21: Thermally conductive film mainly containing an organosilicon compound having a refractive index of less than 1.55 before curing]
With the composition shown in Table 8, (ViMe ₂ SiO _1/2 ) ₂₅ (PhSiO _3/2 ) ₇₅ , HMe ₂ SiO (Ph ₂ SiO) _2.5 SiMe ₂ H, and magnesium hydroxide (particle diameter 3 microns, Specific gravity 2.36) was mixed uniformly. Next, platinum 1,3-divinyltetramethyldisiloxane complex was mixed in such an amount that platinum metal was 2 ppm by mass with respect to the solid content to prepare a curable organopolysiloxane composition. In the composition, the molar ratio (= SiH / Vi ratio) of silicon atom-bonded hydrogen atoms to silicon atom-bonded vinyl groups in the composition related to the hydrosilylation reaction is 1.0. The refractive index of the organosilicon compound represented by (ViMe ₂ SiO _1/2 ) ₂₅ (PhSiO _3/2 ) ₇₅ before curing was 1.540.
The curable organopolysiloxane composition was heated at 70 ° C. for 1 hour and then heated at 150 ° C. for 2 hours to obtain a film as a cured product of the curable organopolysiloxane composition. Table 8 shows the results of measuring the refractive index (25 ° C.) of the matrix material of the film (cured product), the refractive index of the filler (25 ° C.), and the transmittance and thermal conductivity of the film. As shown here, even if an organosilicon compound having a refractive index of less than 1.550 is used as a raw material before curing, if it is a raw material component that forms an organosilicon compound that is a matrix material having a refractive index of 1.550 or more after curing, It can be used as the matrix material of the present invention, and can achieve high transparency and thermal conductivity.

[Comparative Examples 2 and 3: Thermally conductive grease in which the refractive index of the matrix material is less than 1.55]
In the composition shown in Table 9, dimethyl silicone (viscosity 300 cs) and alumina (particle size 12 microns, specific gravity 3.98) or aluminum hydroxide (particle size 30 microns, specific gravity 2.42) were mixed to obtain a grease. . Table 9 shows the measurement results of the refractive index of the matrix material of the obtained grease, the refractive index of the filler, the transmittance of the grease, and its thermal conductivity. In these greases, the refractive index of the matrix material is less than 1.55 (= 1.403), and the refractive index difference between the matrix material and the filler is 0.357 and 0.177, respectively. Was 25% or less, and a transparent heat conductive material could not be obtained.

As described above, by using the organosilicon compound according to the present invention, a matrix material having a refractive index of 1.550 or more, particularly 1.600 or more can be easily designed, and a high refractive index thermally conductive filler and Can be minimized. Therefore, if the organosilicon compound according to the present invention or a matrix material obtained by curing the organosilicon compound is used, not only thermally conductive fillers with refractive indexes of 1.580 and 1.570 such as aluminum hydroxide and magnesium hydroxide, Even if a heat conductive filler having a high refractive index (above 1.600) such as alumina or boehmite is selected, there is an advantage that a transparent heat conductive material (grease, film, thermosoftening composition, etc.) can be designed. is there.

Claims

(A) 100 parts by mass of an organosilicon compound having a refractive index at 25 ° C. of 1.550 or more,
(B) A thermally conductive composition comprising 10 to 2000 parts by mass of a thermally conductive filler.
(A1) 100 parts by mass of an organosilicon compound having a refractive index of 1.550 to 1.750 at 25 ° C.
(B1) 20 to 500 parts by mass of a thermally conductive filler having a refractive index at 25 ° C. of 1.500 to 1.800, and a refractive index of the matrix material composed of component (A1) and component (B1) The thermally conductive composition according to claim 1, wherein the difference in absolute value is 0.050 or less.
2. The organosilicon compound as component (A) or component (A1) comprises one or more types of organosilicon compounds represented by the following (A1-1) to (A1-3): Or the heat conductive composition of 2.
(A1-1) Average unit formula:
(R 1 3 SiO 1/2 ) a (R 1 2 SiO 2/2 ) b (R 2 SiO 3/2 ) c (SiO 4/2 ) d
Wherein R 1 is an alkyl group, an alkenyl group, a phenyl group, a hydrogen atom or a hydroxyl group, R 2 is a phenyl group, a condensed polycyclic aromatic group or a condensed polycyclic aromatic group-containing group, a , B, c, and d are 0.01 ≦ a ≦ 0.8, 0 ≦ b ≦ 0.5, 0.2 ≦ c ≦ 0.9, 0 ≦ d <0.2, and a + b + c + d, respectively. = A number that satisfies 1.)
An organopolysiloxane represented by
(A1-2) General formula (1):
MO x / 2
(In the formula, M is an atom of groups 2A, 2B, 4A, 5A in the periodic table, and x is a valence of M.)
A metalloxy unit represented by the general formula (2):
R 4 a SiO (4-a) / 2
(In the formula, R 4 is an alkyl group, an alkenyl group, an aryl group, an aralkyl group, or a hydrogen atom, and a is a number that satisfies 0 <a ≦ 3.)
A polyorganometallosiloxane comprising at least an organosiloxane unit represented by:
(A1-3) The following average structural formula:
(R M 3 SiO 1/2 ) a (R D 2 SiO 2/2 ) b (R T SiO 3/2 ) c (SiO 4/2 ) d
(Wherein R M , R D and R T are each independently
A monopolar hydrocarbon group, a hydrogen atom, a hydroxyl group, an alkoxy group, a highly polar functional group bonded to a silicon atom via a (n + 1) -valent functional group (Z) represented by -Z- (Q) n or directly A group having a functional group (Q) selected from a hydroxyl group-containing group, a silicon atom-containing hydrolyzable group or a metal salt derivative thereof, or a divalent functional group bonded to the Si atom of another siloxane unit. ,
Of all R M , R D and R T , 50 mol% or more of the monovalent hydrocarbon group is a phenyl group or a naphthyl group,
The molecule contains at least one group represented by -Z- (Q) n. n is a number of 1 or more, a to d are each 0 or a positive number, and a + b + c + d is a number in the range of 2 to 1000. )
An organosilicon compound represented by:
The thermally conductive composition according to any one of claims 1 to 3, wherein the thermally conductive composition or a cured product thereof has a light transmittance of 65% or more at a wavelength of 600 nm at a thickness of 0.2 mm.
The component (B) or component (B1) is one or more kinds of thermally conductive fillers selected from metal hydroxides, metal carbonates, and hydrates of metal oxides. A thermally conductive composition according to claim 1.
The component (B) or the component (B1) is one or more kinds of thermally conductive fillers selected from aluminum hydroxide, magnesium hydroxide, magnesium carbonate, and boehmite, according to any one of claims 1 to 5. Thermally conductive composition.
The thermally conductive composition according to any one of claims 1 to 6, which is a thermally conductive grease.
8. The thermally conductive composition according to claim 1, wherein the thermally conductive composition is cured to form a thermally conductive gel or a thermally conductive rubber.
The heat conductive composition containing the organosilicon compound as component (A) or component (A1) is solid at 25 ° C., and the heat softening temperature of the heat conductive composition is in the range of 40 to 115 ° C. The thermally conductive composition according to any one of claims 1 to 7.
A thermally conductive cured product obtained by curing the thermally conductive composition according to claim 8.
The thermally conductive composition according to claim 9 or the thermally conductive cured product according to claim 10, which is in a sheet form at 25 ° C.
An optical material comprising the thermally conductive composition according to any one of claims 1 to 9 or the thermally conductive cured product according to any one of claims 10 to 11.
A thermally conductive member for a semiconductor device comprising the thermally conductive composition according to any one of claims 1 to 9 or the thermally conductive cured product according to any one of claims 10 to 11.
An optical semiconductor device comprising the thermally conductive composition according to any one of claims 1 to 9 or the thermally conductive cured product according to any one of claims 10 to 11.