JPS6239660A - Gel composition for optical connection - Google Patents

Abstract

PURPOSE:To provide the titled composition having excellent adhesivity to substrate, resistant to the internal crack of gel and the peeling from the substrate caused by thermal shock, and capable of forming a gel resistant to discoloration and variation of physical properties at high temperature, by compounding a specific polyorganosiloxane with specific amount of a specific siloxane and a catalyst. CONSTITUTION:The objective composition can be produced by compounding (A) a polyorganosiloxane having a viscosity of 50-10,000cp and containing 0.1-2 vinyl groups bonded to Si atom in one molecule, wherein the other organic group bonded to the Si atom is a (substituted) univalent hydrocarbon group free from aliphatic unsaturated bond (e.g. methyl group) with (B) a siloxane of formula (R<1> is 1-4C alkyl or phenyl; R<2> is 1-4C alkyl) and (C) a catalyst selected from platinum-based catalyst, palladium-based catalyst and rhodium-based catalyst. The number of H atoms bonded to Si atom of the component B is 0.1-0.8 or 1.5-3.0 based on one vinyl group bonded to Si atom of the component A, and the amount of metallic element of the component C is 0.01-30ppm based on the sum of the components A and B.

Description

[Detailed Description of the Invention] C. Industrial Application Field] The present invention provides the ability to process plastics,
It has excellent adhesion to base materials such as rubber, glass, and metal, does not cause cracks inside the gel or peels from the base material due to thermal shock, and is stable without discoloration or physical property changes at high temperatures. The present invention relates to a gel composition for optical bonding that can form a gel-like material.

[Conventional technology]

Conventionally, various techniques have been known for compositions that can be cured to form gel-like polyorganosiloxane through an addition reaction between a hydrosilyl group and a silicon-bonded vinyl group. It is widely used as an encapsulation material and as an implant in surgical procedures.

Regarding such a polyorganosiloxane composition, JP-A-48-17847 discloses that the amount of hydrogen atoms bonded to the silicon atom is one or less per vinyl group bonded to the silicon atom, and JP-A-54-15957 and JP-A-54-48720 disclose compositions in which the hydrogen atoms are present in an average amount of 1.4 to 1.8 in one molecule of organohydrogensiloxane. The amount of is around 0.3 to 0.8 per vinyl group,
A composition in which a relatively small amount of polyorganosiloxane is present is disclosed, and as a vinyl group-containing polyorganosiloxane, JP-A-54-
No. 15957 discloses polydimethylsiloxane terminal-capped with methylvinylphenylsiloxy groups,
48720 proposes the use of a polysiloxane containing in one molecule at least two vinyl groups bonded to silicon atoms and one hydroxyl group.

However, such compositions that can be cured into a gel-like state or gel-like products obtained therefrom have the following drawbacks in common.

■ Because the adhesiveness is low, it does not adhere to the base material, and when used for potting electronic equipment parts, gaps are created between the parts and the gel-like material, which allows moisture to enter, causing corrosion and poor insulation. becomes.

(2) The vinyl groups remaining in the gel are oxidized at high temperatures, resulting in poor heat resistance in an oxidizing atmosphere.

(2) Since the amount of polyorganohydrodiene siloxane in the composition is small, errors in blending the siloxane or the mixture containing it during blending immediately before curing can cause a significant difference in the softness of the gel-like product.

(2) It is difficult to synthesize the methylvinylphenylsiloxy end group as shown in JP-A-54-15957.

[Problem that the invention seeks to solve]

In order to solve these problems, Japanese Patent Application Laid-Open No. 56-1432
In Publication No. 41, the amount of hydrogen atoms is basically determined by the vinyl group 1
A composition is disclosed in which the above-mentioned problems 1 to 2 are present in an amount of 0.5 to 5 per piece, thereby almost solving the above-mentioned problems. However, in all of these compositions that can be cured into a gel form, cracks occur inside the silicone gel due to thermal shock, so it has been impossible to achieve the purpose of optical bonding. In addition, in recent years, transparent plastics have begun to be used in addition to glass in optical bonding applications, and conventional gels have poor adhesion to these plastics and can cause separation from the base material due to thermal shock. there were.

[Means for solving problems]

The present invention eliminates these drawbacks, and provides excellent adhesion to substrates, no cracks in the silicone gel due to thermal shock, no peeling from the substrate, and stable optical properties that do not discolor at high temperatures. A bonding gel composition is provided.

The present inventors investigated a composition that would solve these problems, and found that instead of the conventionally used polyorganohydrodiene siloxane, the general formula R'SI (
The purpose was achieved by using a siloxane represented by OSIR22H) s (R' + R'' is as described above) and by adjusting the amount of catalyst to 0.01 to 30 ppm as the amount of catalytic metal element relative to the polyorganosiloxane mixture. The present invention has been completed based on this discovery.

That is, the present invention provides (A) an average of 0.1 to 2.0 vinyl groups to be bonded to the silicon atom in one molecule, and the remaining organic groups to be bonded to the silicon atom are substituted with no aliphatic unsaturation. or an unsubstituted monovalent hydrocarbon group with a viscosity of 50 to 100 at 25°C
,000 cP polyorganosiloxane (B) general formula % formula %) (wherein R1 is a C8 to C4 alkyl group or phenyl group,
RZ represents a C3-C4 alkyl group), the number of hydrogen atoms bonded to the silicon atom is (8)
0.1 to 1 vinyl group bonded to silicon atom
an amount of 0.8 or 1.5 to 3.0, and (C) a catalyst selected from the group consisting of platinum-based catalysts, palladium-based catalysts, and rhodium-based catalysts; the sum of (A) and (B); 0.01 to 30 pp as the amount of catalytic metal element relative to the amount
The present invention relates to a gel-like composition for optical bonding, characterized in that the composition comprises an amount of m.

The polyorganosiloxane as component (A) used in the present invention has an average of 0.1 to 2.0, preferably 0.1 to 1.4 vinyl groups bonded to silicon atoms in one molecule. be. If the amount of vinyl groups is less than 0.1, the amount of polyorganosiloxane that does not participate in crosslinking will increase, and the physical properties of the gel-like product obtained by curing and the adhesion to the substrate will decrease significantly. . Moreover, if the amount of vinyl groups is more than 2.0, the characteristic of the present invention, which is to obtain a soft gel-like material that does not discolor at high temperatures, cannot be exhibited.

Among the m groups bonded to the silicon atom of the polyorganosiloxane (A), those other than the vinyl group mentioned above are:
Alkyl groups such as methyl group, ethyl group, propyl group, butyl group, amino group, hexyl group, octyl group, decyl group, dodecyl group, aryl group such as phenyl group, β-
Aralkyl groups such as phenylethyl group, β-phenylpropyl group, and chloromethyl group, cyanoethyl l,3
, 3.3-) Substituted hydrocarbon groups such as refluoropropyl groups are exemplified, but because of their ease of synthesis, ease of handling in an uncured state, and the heat resistance and physical properties of gel-like products, A methyl group is preferred. In addition, phenyl may contain up to 8 mol% of all organic groups when cold resistance is required, and up to 50 mol% of all organic groups when particularly high heat resistance, radiation resistance, or high refractive index is required. It is recommended to introduce groups. Viscosity is 50-10 at 25℃
0.000cP, preferably 300-5,0OOcP
selected from the range. When used in botting, a range of 500 to 1,500 cP is most preferred. 5
If it is lower than 0 cP, it will flow easily and the physical properties after reaction will be poor. Moreover, if it exceeds 100,000 cP, workability will deteriorate.

The siloxane skeleton of the polyorganosiloxane (8) is
Although it may be linear or branched, or a mixture of both, it is preferably substantially linear for ease of synthesis and for imparting appropriate softness to the gel-like material. It is acceptable for a small amount of cyclic polyorganosiloxane to coexist, but even if it has a vinyl group bonded to a silicon atom, the reactivity is low and it does not contribute to the formation of a sticky gel. The vinyl group in polyorganosiloxane may be bonded to either a silicon atom in the middle of the molecule or a silicon atom at the end of the molecule, but it is preferable to bond to the silicon atom at the end due to the reaction rate and the effect of forming a gel-like substance due to the reaction. It is preferable.

Such polyorganosiloxane (A) includes, for example, a vinyl group-containing polyorganosiloxane that has a vinyl group bonded to a silicon atom at both ends, and a linear or branched polyorganosiloxane that does not contain a vinyl group. If available, it is blended with a polydiorganosiloxane that does not contain vinyl groups to satisfy the average molecular weight and amount of vinyl groups that achieve the above-mentioned viscosity range, and an acid catalyst such as sulfuric acid, hydrochloric acid, activated clay, or potassium hydroxide. It is synthesized by cutting and equilibrating siloxane using conventional methods in the presence of an alkali catalyst such as tetramethylammonium hydroxide. In this case, a cyclic polysiloxane, particularly a cyclic polysiloxane containing no vinyl group, may be used in combination as part of the raw material. After equilibration, the catalyst is removed by a conventional method, and by-product or unreacted low molecular weight polyorganosiloxane is removed by heating under reduced pressure, thereby purifying the product.

The siloxane (B) component used in the present invention is represented by the general formula R'5i(OSiR"□H)3, and reacts with the vinyl group of the polyorganosiloxane (8) to form a gel-like substance. This is a feature of the present invention.

Examples of R1 include alkyl groups such as methyl group, ethyl group, propyl group, butyl group; and phenyl group,
A methyl group or a phenyl group is preferred because it is easy to synthesize and provides a good gel-like product. Examples of R2 include alkyl groups such as methyl, ethyl, propyl, and butyl groups, and methyl is preferred from the viewpoint of ease of obtaining materials and synthesis. These siloxanes may be used alone or in combination of two or more (these can be easily obtained by cohydrolyzing chlorosilanes such as methyltrimethoxysilane, phenyltrimethoxysilane, and dimethylchlorosilane by a conventional method). .

The blending amount of component (B) is 0.1 to 0.8 hydrogen atoms to be bonded to the silicon atom in component (B) for each vinyl group bonded to the silicon atom in component (A). 1.5-3
．． The amount is 0, preferably 0.3 to 0.8.

If it is less than 0.1, crosslinking will not proceed sufficiently, and the gel-like material will not only become too soft, but also become noticeably discolored at high temperatures. Further, if the number exceeds 0.8 and is less than 1.5, the cured product will become rubber-like, and if the number exceeds 3.0, the resulting gel-like material will become hard over time.

The catalyst of component (C) used in the present invention is for promoting the addition reaction between the vinyl group of component (A) and the hydrosilyl group of component (B). Platinum catalysts such as acids, complexes of platinum and olefins, complexes of platinum and ketones, complexes of platinum and vinylsiloxane, tetrakis(triphenylphosphine)palladium, mixtures of palladium black and triphenylphosphine Palladium-based catalysts such as
Alternatively, a rhodium-based catalyst can be used, but a platinum-based catalyst is preferred because of its catalytic effect and ease of handling. The blending amount of component (C) is such that the amount of the catalytic metal element is in the range of 0.01 to 30 ppn+ relative to the total amount of (A) and (B).

If it is less than 0.01 ppm, the addition reaction will not proceed sufficiently and the gel-like material will become too soft, and if it exceeds 30 ppm, discoloration at high temperatures will become significant and the features of the present invention will not be exhibited.

The composition of the present invention may be stored in a single container by the presence of a reaction inhibitor such as an acetylenic compound or by using a platinum-based catalyst with low activity at room temperature.
) and (B) in the same container and (C) in separate containers, or (A)
A portion of (Ill) and most of (A) and (C) may be stored in separate containers, mixed uniformly just before curing, and degassed under reduced pressure before use. Furthermore, by adding an inorganic filler to the composition of the present invention as needed, workability, hardness after curing, mechanical strength, etc. can be adjusted depending on the application. Examples of such inorganic fillers include fumed silica, silica aerogel, and precipitated silica. Also, solvents such as toluene and hexane, viscosity modifiers such as polydimethylsiloxane, additional haze polymers such as alkenyl-containing polysiloxanes, cure inhibitors such as acetylene alcohol and its reaction products with polysiloxanes, etc. There is no problem even if these are used in combination to the extent that the effects of the present invention are not lost.

〔Effect of the invention〕

According to the present invention, the silicone gel has excellent adhesion to the substrate at room temperature or by slight heating, does not cause cracks inside the silicone gel or peels from the substrate due to thermal shock, and does not discolor or change physical properties at high temperatures. A gel composition for optical bonding that forms a stable gel-like substance with a small amount was obtained.

The composition of the present invention is useful for botting, encapsulation, and encapsulation of electrical/electronic parts, especially optical coupling bands that require optical transparency, parts where design value is important, and human body models. Used for manufacturing, etc.

〔Example〕

Examples of the present invention will be shown below. In the examples, all parts are by weight, and viscosity is the viscosity at 25°C. Note that the symbols Me, Vi, and ph represent a methyl group, a vinyl group, and a phenyl group, respectively.

Example 1 Compositions 1 to 6 were prepared by uniformly mixing the materials shown below according to the compounding ratios shown in Table 1. However, compositions 1 and 2 are products of the present invention, and compositions 3 to 6 are comparative products.

<As component (A)> Polysiloxane A-1: Polydimethylsiloxane containing a vinyl group represented by the average formula. Viscosity: 650 cP <As component (B)> B-1: Siloxane represented by PhSi(OSiMeJ)3 B-2: Siloxane represented by MeSi(OSiMeJ)i B-3: Polymethylhydrodiene siloxane represented by the average formula .

B-4: Average formula Polymethylhydrodienesiloxane represented by

B-5=average formula Polymethylhydrodienesiloxane represented by

<As component (C)> C-1: One obtained by heating chloroplatinic acid and tetramethyltetravinylcyclotetrasiloxane.

Platinum content: 2.0% by weight as platinum When these compositions were heated at 50°C for 2 hours, they all cured and the corresponding transparent gels 1 to 6 were formed. Obtained. When the penetration degree of the gel-like material was measured in accordance with ASTM D-1403, the values shown in the initial values in Table 2 were obtained.

Heat Resistance Test The gels 1 to 6 obtained by curing were placed in an air circulation oven at 150° C., and the change in penetration over time was measured, and the degree of discoloration was measured using the APHA value. The results are shown in Table 2.

40g of the composition of Zan Wuchengtang fish 1 to 6 was placed in a tube with an inner diameter of 18 mm and a depth of 180 mm.
It was injected into a glass test tube (mm) and heated at 50°C for 2 hours to harden, and then tested in a thermal shock tester at 20°C
A thermal shock test was carried out a predetermined number of times in a cycle of 2h←→80°C/2h, and the presence or absence of cracks inside the gel was visually confirmed.

The results are shown in Table 2.

A spacer was applied to the test specimen shown in FIG. 1, and the compositions of Arashi 1 to 6 were injected thereinto, and after curing by heating at 50° C. for 2 hours, the spacer was removed. Using a tensile tester with an autograph (manufactured by Shimadzu Corporation), these were pulled in a direction perpendicular to the adhesive surface at 50 mm/min to determine the maximum tensile stress, elongation at break,
and cohesive failure rate were measured. The results are shown in Table 2.

These results show that the composition according to the present invention shows little discoloration due to heating, has excellent impact resistance, and has extremely good adhesion.

Example 2 The same formulation as l'hl in Example 1 except that a polyorganosiloxane containing vinyl groups and phenyl groups represented by the average formula was used instead of 1100 parts of polysiloxane A-1 used in Example 1. A composition was obtained by the ratio. When this material was heated at 50°C for 2 hours, the penetration was 67 and the A P I + A value was 1.
0 gel-like material was obtained. Furthermore, when it was heated at 150° C. for 1000 hours, it remained in good condition with a penetration of 60 and an APHA value of 25. In addition, the same impact resistance test and adhesion test as in Example 1 were conducted, but in the impact resistance test, no cracking was observed even after 100 cycles, and in the adhesion test, the maximum tensile stress was 110 gf/cm2, and the elongation at break was 900. %, and the cohesive failure rate was 100%, which was a good value.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a test specimen used for measurement in an adhesion test. Note that the unit of numerical values in the figure is mm. 1... Acrylic resin plate 2... Silicone gel

Claims (1)

[Scope of Claims] 1(A) An average of 0.1 to 2.0 vinyl groups bonded to the silicon atom exist in one molecule, and the remaining organic groups bonded to the silicon atom contain aliphatic unsaturation. It is a substituted or unsubstituted monovalent hydrocarbon group with a viscosity of 50 to 10 at 25°C.
0,000 cP polyorganosiloxane (B) general formula R^1Si(OSiR^2_2H)_3 (wherein R^1 is an alkyl group of C_1 to C_4 or a phenyl group, R^2 is an alkyl group of C_1 to C_4 )
In the siloxane represented by, the number of hydrogen atoms bonded to the silicon atom is 0.1 to 0.8 or 1.5 to 3.0 per vinyl group bonded to the silicon atom of (A). and (C) a catalyst selected from the group consisting of platinum-based catalysts, palladium-based catalysts, and rhodium-based catalysts, 0.01 to 30 pp as the amount of catalytic metal element relative to the total amount of (A) and (B).
A gel composition for optical bonding characterized by comprising an amount of m. 2. The composition according to claim 1, wherein the vinyl group bonded to the silicon atom of 2(A) is present at the end of the molecule. 2. The composition of claim 1, wherein 3(A) is a substantially linear polyorganosiloxane. 4 (A) in which the organic group other than the vinyl group bonded to the silicon atom is selected from the group consisting of methyl group and phenyl group 1
2. The composition according to claim 1, wherein the phenyl group is a valent hydrocarbon group, and the amount of the phenyl group is not more than 50 mol% of the total organic groups. 5. The composition according to claim 4, wherein the organic group other than the vinyl group bonded to the silicon atom in 5(A) is a methyl group. The viscosity of 6(A) at 25°C is 300 to 5,000c
The composition according to claim 1, which is P. The composition according to claim 1, wherein R^1 in 7(B) is a methyl group or a phenyl group. 8. The composition according to any one of claims 1 to 7, wherein R^2 in 8(B) is a methyl group. The amount of 9 (B) is such that the number of hydrogen atoms bonded to the silicon atom of (B) is 0.3 to 0.8 per vinyl group bonded to the silicon atom of (A). A composition according to claim 1. 10. The composition according to claim 1, wherein the catalyst in 10(C) is a platinum-based catalyst.