JP6828660B2 - Silicone Adhesive Composition and Adhesive Method - Google Patents

Description

The present invention relates to a silicone adhesive composition and an adhesion method, and more specifically, for a silicone adhesive composition having excellent transparency, which firmly adheres to a highly transparent adherend such as glass or polycarbonate, and the like. Regarding the bonding method that was used.

Conventionally, as a method for producing a composite of an adherend such as metal or resin and silicone rubber, a method of adhering the adherend and unvulcanized silicone rubber via an adhesive (adhesion with a primer, Patent Document 1). (See) and a method of adding an adhesive component to silicone rubber to achieve vulcanization and adhesion at the same time (self-adhesive, see Patent Document 2) are known.
Volatile organic compounds (VOCs) are widely used as adhesive solvents in bonding methods using primers, but in recent years there has been a strong demand for reductions in VOC emissions in order to reduce the health of workers and the environmental burden. ..
On the other hand, as a self-adhesive silicone rubber, a large number of products to which an organoalkoxysilane having an organic functional group is selectively added have been put on the market.

However, there is no known silicone adhesive that has high adhesiveness to a highly transparent adherend such as glass or polycarbonate and does not impair its transparency.
For example, in Patent Document 3, a cured sheet having a Williams plasticity (JIS6249, 25 ° C.) of 400 to 800 and a thickness of 1 mm between the glass for building materials and the metal fittings for building materials has a visible light transmittance of 50% or more. A joining method is described in which a certain thermoplastic silicone rubber adhesive composition is interposed and the thermosetting silicone rubber adhesive is heated after crimping. However, it is a "highly transparent material that does not break" and can be used as a glass substitute for polycarbonate. Adhesiveness is not mentioned.

On the other hand, in Patent Document 4, by using a specific cross-linking agent and a specific adhesive aid in the addition-curable silicone rubber composition, resins such as polycarbonate and polyethylene terephthalate, and metals such as iron, aluminum and stainless steel are used. It is stated that a silicone rubber adhesive composition that can be adhered to and has a small compression set can be obtained, but since it is a liquid material suitable for injection molding, there is a problem of mixing liquid A / liquid B. Further, in the case of surface bonding, there is a problem that it is very difficult to apply a thin film of the adhesive to the base material.

Japanese Unexamined Patent Publication No. 2001-260233 Japanese Patent No. 4681634 Japanese Patent No. 4875245 Japanese Unexamined Patent Publication No. 2010-196011

The present invention has been made in view of such circumstances, and can be used as a sheet or the like which has adhesiveness to polycarbonate, gives a cured product having a total light transmittance of 90% or more, and is easy to arrange. It is an object of the present invention to provide a suitable silicone adhesive composition and an adhesive method using the same.

As a result of diligent studies to achieve the above object, the present inventor has added a hydrogen atom bonded to at least one silicon atom in one molecule to a miraculous type silicone rubber composition highly filled with fumigant silica. The present invention has been completed by finding that a highly transparent silicone rubber adhesive composition that firmly adheres to polycarbonate after curing can be obtained by adding an organosilicon compound that contains at least one aromatic hydrocarbon skeleton. did.

That is, the present invention
1. 1. (A) The following average composition formula (I)
R ¹ _a SiO _{(4-a) / 2} (I)
(In the formula, R ¹ represents an unsubstituted or substituted monovalent hydrocarbon group independently of each other, but at least two in one molecule are aliphatic unsaturated groups, and a is 1.95 to 2. Represents a positive number of 0.05.)
Represented by 100 parts by mass of organopolysiloxane having a degree of polymerization of 100 or more,
(B) 60 to 150 parts by mass of fumes silica having a BET specific surface area of more than 200 m ² / g,
(C) 0.1 to 30 parts by mass of an organohydrogenpolysiloxane containing a hydrogen atom bonded to at least two silicon atoms in one molecule.
(D) Hydrosilylation reaction catalyst An organosilicon compound 0.02 containing a catalytic amount and (E) a hydrogen atom bonded to at least one silicon atom in one molecule and having at least one aromatic hydrocarbon skeleton. Silicone adhesive composition, characterized by containing ~ 5.0 parts by mass,
2. 2. The silicone adhesive composition of 1 in which the component (B) is a surface-treated fumigant silica having a BET specific surface area of 210 to 500 m ² / g.
3. 3. 1 or 2 silicone adhesive compositions that are sheet-like, film-like, tape-like or round-bar-like in the unvulcanized state,
4. An adhesive method in which the silicone adhesive composition according to any one of 1 to 3 is brought into contact with the object to be adhered and then heat-cured under pressure.
5. Provided 4 is an adhesion method in which the object to be adhered is glass or polycarbonate.

The silicone rubber adhesive composition of the present invention is a mirrorable type material capable of extrusion molding, calendar molding, etc., and the cured product has high transparency while containing silica and is good for glass and polycarbonate. Since it has excellent adhesiveness, it can be suitably used for building materials and as a light guide sheet for optical equipment.

It is the schematic explanatory drawing of the 180 ° peel test performed in an Example.

Hereinafter, the present invention will be described in more detail.
The silicone adhesive composition according to the present invention contains the following components (A) to (E).
(A) The following average composition formula (I)
R ¹ _a SiO _{(4-a) / 2} (I)
(In the formula, R ¹ represents an unsubstituted or substituted monovalent hydrocarbon group independently of each other, but at least two in one molecule are aliphatic unsaturated groups, and a is 1.95 to 2. Represents a positive number of 0.05.)
Represented by 100 parts by mass of organopolysiloxane having a degree of polymerization of 100 or more,
(B) 60 to 150 parts by mass of fumes silica having a BET specific surface area of more than 200 m ² / g,
(C) 0.1 to 30 parts by mass of an organohydrogenpolysiloxane containing a hydrogen atom bonded to at least two silicon atoms in one molecule.
(D) Hydrosilylation reaction catalyst An organosilicon compound 0.02 containing a catalytic amount and (E) a hydrogen atom bonded to at least one silicon atom in one molecule and having at least one aromatic hydrocarbon skeleton. ~ 5.0 parts by mass

(1) Component (A) In the above average composition formula (I), examples of the monovalent hydrocarbon group of R ¹ include an alkyl group, an alkenyl group, an aryl group, and an aralkyl group. The number of carbon atoms is not particularly limited, but the number of carbon atoms is preferably 1 to 12, and more preferably 1 to 8 carbon atoms.
The alkyl group may be linear, branched or cyclic, and specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, and the like. Linear or branched alkyl groups such as n-hexyl, n-heptyl and n-octyl groups; cycloalkyl groups such as cyclopentyl and cyclohexyl groups can be mentioned.
The alkenyl group may be linear, branched or cyclic, and specific examples thereof include a linear or branched alkenyl group such as ethenyl (vinyl), n-1-propenyl, n-2-propenyl (allyl). Cycloalkenyl groups such as 3-cyclopentene-1-yl, 3-cyclohexene-1-yl group and the like can be mentioned.
Specific examples of the aryl group include phenyl, naphthyl, tolyl group and the like.
Specific examples of the aralkyl group include benzyl, 2-phenylethyl group and the like.

In these monovalent hydrocarbon groups, a part or all of the hydrogen atom may be substituted with a halogen atom (fluorine, chlorine, bromine, iodine atom) or another substituent such as a cyano group. Examples include a trifluoropropyl group and the like.

Among these, as R ¹ , a methyl group, a vinyl group, a phenyl group and a trifluoropropyl group are preferable, and a methyl group and a vinyl group are more preferable.

Specifically, an organopolysiloxane in which the main chain consists of repeating dimethylsiloxane units, or a phenyl group, vinyl group, 3,3, in a part of the dimethylpolysiloxane structure consisting of repeating dimethylsiloxane units constituting the main chain. Organopolysiloxanes containing diphenylsiloxane units having a 3-trifluoropropyl group or the like, methylphenylsiloxane units, methylvinylsiloxane units, methyl-3,3,3-trifluoropropylsiloxane units and the like are preferable.

As described above, the organopolysiloxane used in the present invention, among all R ¹ that are present in one molecule, at least two are alkenyl radicals, although an aliphatic unsaturated group such as a cycloalkenyl group, especially a vinyl group Is preferable.
In this case, 0.01 to 20 mol% of the total R ¹ is preferably an aliphatic unsaturated group, and more preferably 0.02 to 10 mol% is an aliphatic unsaturated group.
The aliphatic unsaturated group may be bonded to a silicon atom at the end of the molecular chain, a silicon atom in the middle of the molecular chain, or both, but at least the end of the molecular chain. It is preferably bonded to the silicon atom of.
Further, from the viewpoint of ensuring transparency, of all R ¹ , preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably all R ¹ except for aliphatic unsaturated groups are alkyl groups, particularly It is preferably a methyl group.

Further, a is a positive number of 1.95 to 2.05, but a positive number of 1.98 to 2.02 is preferable, and a positive number of 1.99 to 2.01 is more preferable.

The organopolysiloxane of the component (A) used in the present invention is a triorgano having a molecular chain terminal such as a trimethylsiloxy group, a dimethylphenylsiloxy group, a dimethylhydroxysiloxy group, a dimethylvinylsiloxy group, a methyldivinylsiloxy group, or a trivinylsiloxy group. It is preferably sealed with a siloxy group.
Specific examples thereof include methylvinyl polysiloxane, methylphenylvinylpolysiloxane, and methyltrifluoropropylvinylpolysiloxane.

Such an organopolysiloxane can be obtained, for example, by (co) hydrolyzing and condensing one or more of organohalogenosilanes, or by making cyclic polysiloxanes (trimers of siloxanes, tetramers, etc.) alkaline or acidic. It can be obtained by ring-opening polymerization using the catalyst of.
These are basically linear diorganopolysiloxanes, but the component (A) may be a mixture of two or three or more kinds having different molecular weights (degrees of polymerization) and molecular structures.

In the present invention, the degree of polymerization of the organopolysiloxane of the component (A) is 100 or more, preferably 100 to 100,000, more preferably 3,000 to 20,000. This degree of polymerization can be measured as a polystyrene-equivalent weight average degree of polymerization by gel permeation chromatography (GPC) analysis.

(2) Component (B) The aerosolized silica having a BET specific surface area of the component (B) exceeding 200 m ² / g is added to obtain a silicone adhesive composition having excellent transparency and mechanical strength. It is a thing.
In order to improve the transparency of the silicone adhesive composition, the BET specific surface area needs to exceed 200 m ² / g, and in particular, 210 m ² / g or more is preferable, and 250 m ² / g or more is more preferable. The upper limit is not particularly limited, but is usually 500 m ² / g or less.
Generally, examples of silica used in the silicone adhesive composition include aerosol silica, precipitated silica, and the like. However, since the transparency is lowered when precipitated silica is used, aerosol silica is used in the present invention. ..

Further, as the fumes silica, those whose surface is hydrophobized with chlorosilane, alkoxysilane, hexamethyldisilazane or the like are also preferably used, and particularly when the surface treatment with hexamethyldisilazane is applied, the silicone adhesive composition Higher transparency.
As for such a silica surface treatment agent such as hexamethyldisilazane, a silica surface-treated agent such as hexamethyldisilazane may be mixed with the component (A) in advance, or the component (A) is kneaded with the silica. At that time, a surface treatment agent may be blended and the surface treatment of silica may be performed during kneading.
The amount of the surface treatment agent used is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of fumes silica.

The amount of fumigant silica added as the component (B) is 60 to 150 parts by mass with respect to 100 parts by mass of the organopolysiloxane of the component (A), but 70 to 120 parts by mass is preferable. If it is less than 60 parts by mass, the transparency of the sheet obtained by curing the silicone adhesive composition is lowered. If it exceeds 150 parts by mass, it becomes difficult to disperse silica in the silicone adhesive composition.

(3) Component (C) The organohydrogenpolysiloxane of component (C) contains a hydrogen atom (that is, a SiH group) bonded to at least two silicon atoms in one molecule, and has the following average composition formula (that is, SiH group). Conventionally known organohydrogenpolysiloxane represented by II) can be applied.
R ² _b H _c SiO _{(4-bc) / 2} (II)

In formula (II), R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, preferably having no aliphatic unsaturated bond, independently of each other.
Specific examples of the monovalent hydrocarbon group include those having 1 to 6 carbon atoms among the groups exemplified by the above formula (I), among which methyl, ethyl, n-propyl, n-butyl and n are used. -Alkyl groups such as pentyl, n-hexyl and cyclohexyl groups; cycloalkenyl groups such as 3-cyclohexene-1-yl group; aryl groups such as phenyl groups; 3,3,3-trifluoropropyl groups, cyanomethyl groups and the like. preferable.
Preferably b is a positive number satisfying 0.7 to 2.1, c is 0.18 to 1.0, and b + c is a positive number satisfying 0.8 to 3.0, and more preferably b is 0.8 to 0.8. 2.0 and c are positive numbers satisfying 0.2 to 1.0, and b + c are positive numbers satisfying 1.0 to 2.5.

The molecular structure of the organohydrogenpolysiloxane may be linear, cyclic, branched, or three-dimensional network. In this case, the number (or degree of polymerization) of silicon atoms in one molecule is preferably 2 to 300, and particularly 4 to 200 silicon atoms liquid at 25 ° C. are preferably used.
Further, the hydrogen atom (SiH group) bonded to the silicon atom may be at the end of the molecular chain, at the side chain, or both, and at least two (usually 2 to 300) in one molecule. , Preferably 3 or more (for example, 3 to 200), more preferably about 4 to 150 are used.

Specific examples of the organohydrogenpolysiloxane of the component (C) include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, and methylhydrogencyclopolysiloxane. Methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, Tris (dimethylhydrogensiloxy) methylsilane, Tris (dimethylhydrogensiloxy) phenylsilane, both-terminal trimethylsiloxy group-blocking methylhydrogenpolysiloxane, both-terminal trimethylsiloxy group-blocking dimethyl Siloxane / methylhydrogensiloxane copolymer, double-ended dimethylhydrogensiloxy group-blocked dimethylpolysiloxane, double-ended dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, double-ended trimethylsiloxy group-blocked methylhydrogen Siloxane / diphenylsiloxane copolymer, both-terminal trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane / dimethylsiloxane copolymer, cyclic methylhydrogenpolysiloxane, cyclic methylhydrogensiloxane / dimethylsiloxane copolymer, cyclic methylhydro Gensiloxane / diphenylsiloxane / dimethylsiloxane copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 In a copolymer consisting of a unit and (C ₆ H ₅ ) SiO _3/2 unit, or in each of the above-mentioned exemplified compounds, a part or all of the methyl group may be an ethyl group, an n-propyl group or other alkyl group. Examples thereof include those substituted with an aryl group such as a phenyl group.

The blending amount of the organohydrogenpolysiloxane of the component (C) is 0.1 to 30 parts by mass with respect to 100 parts by mass of the organopolysiloxane of the component (A), preferably 0.1 to 10 parts by mass. More preferably 0.3 to 10 parts by mass.
The blending amount of this organohydrogenpolysiloxane is the molar ratio of the hydrogen atom (that is, SiH group) bonded to the silicon atom in the component (C) to the alkenyl group bonded to the silicon atom in the component (A) (that is, the SiH group). The amount of SiH group mol / alkenyl group mol) is preferably 0.5 to 10, more preferably 1 to 7, and even more preferably 1.5 to 5.

(4) Component (D) As the hydrosilylation reaction catalyst of the component (D), a known hydrosilylation reaction catalyst can be used without limitation.
Specific examples thereof include platinum black, second platinum chloride, platinum chloride acid, a reaction product of platinum chloride acid and monovalent alcohol, a complex of platinum chloride acid and olefins, and a platinum-based catalyst such as platinum bisacetacetate; Platinum-based catalysts; rhodium-based catalysts and the like can be mentioned.
The blending amount of this hydrosilylation reaction catalyst can be a catalytic amount, and is usually 0.1 to 10 parts by mass with respect to 100 parts by mass of the component (A) as a metal content such as platinum.

(5) Component (E) The component (E) acts as an adhesive-imparting component, and is an organic substance having at least one SiH group in one molecule and at least one perfume hydrocarbon skeleton. Although it is a silicon compound, an organosilicon compound having 1 to 100 silicon atoms, particularly 2 to 30 is preferable.
Specific examples of the aromatic hydrocarbon skeleton include 2-hexavalent, particularly 2-4-valent, benzene ring structure, naphthalene ring structure, anthracene ring structure and the like.

The preferred component (E) has at least one, preferably 1 to 20, more preferably about 2 to 10 SiH groups in one molecule, and at least one, preferably 1 to 4 fragrances. It has a group hydrocarbon skeleton and further has an epoxy group such as a glycidoxy group; an alkoxysilyl group such as a trimethoxysilyl group, a triethoxysilyl group and a methyldimethoxysilyl group; an ester group; an acrylic group; a methacryl group; an anhydrous carboxy group; an isocyanate group. Group; Amino group; Organic silicon compound which may contain one or more functional groups such as amide group, and the number of silicon atoms is 1 to 30, preferably 2 to 20, more preferably about 4 to 10. Examples thereof include linear or cyclic organosiloxane oligomers and organoalkoxysilanes.
Specific examples of such compounds include the compounds shown below.

（式中、ｎは、１〜４の整数を表す。）

(In the formula, n represents an integer of 1 to 4.)

Here, X is a group represented by the following formula.

Y is any group selected from the following formula.

Z is any group selected from the following formula.

R ⁴ is any group selected from the following equations.

R ⁵ is any group selected from the following equations.

R ⁶ and R ⁷ are unsubstituted or substituted monovalent hydrocarbon groups, and examples thereof are the same as those of R ¹ above.
Further, e is 1 to 10, f is 1 to 4, g is 1 to 20, h is 0 to 50, and i is 0 to 50. More preferably, e is 1 to 10, f is 1, and g is 1. 1 to 10, h is 0 to 20, i is 0 to 20.

The amount of the component (E) added is 0.02 to 5.0 parts by mass with respect to 100 parts by mass of the component (A), preferably 0.1 to 3 parts by mass, and 0.2 to 1 part by mass. Is more preferable. If the amount added is less than 0.02 parts by mass, the adhesive strength is lowered, and if it exceeds 5.0 parts by mass, the total light transmittance is lowered and the haze value is increased.

In addition to the above components, a flame retardant-imparting agent, an ultraviolet absorber, a wavelength converter, a colorant, etc. may be added to the silicone adhesive composition of the present invention as long as the object of the present invention is not impaired. it can.

The silicone adhesive composition of the present invention can be obtained by kneading a predetermined amount of each of the above-mentioned components with a two-roll, kneader, Banbury mixer or the like.

When molding the silicone adhesive composition of the present invention, examples of the molding method include press molding in a state of being laminated on the adherend, press molding using vacuum lamination, and the like.
The curing conditions are not particularly limited, but in general, heat curing conditions of 80 to 200 ° C., preferably 100 to 150 ° C. for 5 minutes to 1 hour, preferably about 5 to 30 minutes can be adopted.
After heat curing, post-cure may be performed at 120 to 200 ° C. for about 10 minutes to 10 hours.

The silicone adhesive composition of the present invention can be made into a highly transparent silicone rubber by molding and curing by a method such as press molding.
Further, by laminating with a highly transparent adherend such as glass or polycarbonate, a laminated body having excellent optical characteristics can be obtained.
The silicone adhesive composition of the present invention is mainly used for optical purposes, and is suitably used for an anti-scattering sheet sandwiched between a condensing optical member, an optical sheet of an LED backlight device, and a laminated glass. ..

In the silicone adhesive composition of the present invention, the total light transmittance of a cured product sheet having a thickness of 2 mm is preferably 90% or more. If it is 90% or more, the transparency when a composite with glass or polycarbonate is produced is sufficient.
Further, the haze value of the cured product sheet having a thickness of 2 mm is preferably 10 or less, more preferably 8 or less, as measured by a direct reading haze computer HGM-2 manufactured by Suga Test Instruments Co., Ltd. When the haze value exceeds 10, the light diffusion is too large, and the incident light when used for the optical waveguide plate or the like does not reach the farthest portion of the optical waveguide plate, and the brightness may be uneven.

The silicone adhesive composition of the present invention can be processed into a sheet shape or a film shape by a calendar roll, and can be processed into various fixed shapes such as a tape shape or a round bar shape by extrusion processing.
The silicone adhesive composition processed into a predetermined shape is preferably sandwiched between a release sheet such as polyethylene in order to maintain the shape and prevent sticking.

As a method of using the silicone rubber of the present invention, for example, an unvulcanized silicone adhesive composition processed into a sheet is sandwiched between two adherend panels, and the laminate is placed in a heated vacuum laminator. A method of forming a composite by pressing under vacuum can be mentioned.
In this case, during vacuum laminating molding, unvulcanized silicone flows into the unevenness of the adherend, and the cross-linking reaction of the silicone proceeds to develop adhesiveness.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
In the following, the "part" of the unit of the blending amount is a mass part. The weight average molecular weight and the weight average degree of polymerization are polystyrene-equivalent values in gel permeation chromatography (GPC) analysis.

[Example 1]
100 parts of organopolysiloxane having an average degree of polymerization of about 6,000, consisting of 99.425 mol% of dimethylsiloxane unit, 0.50 mol% of methylvinylsiloxane unit, and 0.025 mol% of dimethylvinylsiloxane unit, BET ratio. Add 70 parts of silica (trade name Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.) with a surface area of 300 m ² / g, 16 parts of hexamethyldisilazane as a dispersant, and 4 parts of water, knead with a kneader, and bring to 170 ° C. The compound-1 was prepared by heat treatment for 2 hours.
For 100 parts of the prepared compound, 0.5 each of C-25A (platinum catalyst) / C-25B (organohydrogenpolysiloxane) (both manufactured by Shin-Etsu Chemical Industry Co., Ltd., the same applies hereinafter) as an addition cross-linking curing agent. A mixture of parts / 2.0 parts and an addition reaction product of tetramethylcyclotetrasiloxane represented by the following formula (i) and diallyl bisphenol A [in the following formula (i), (polymer of y = 1)). : (Polymer of y = 2) = 2.5: 1 (mass ratio)] 0.25 parts were mixed with two rolls to obtain a silicone adhesive composition.

（式中、ｙは１または２であり、ｘ＋ｙ＝４であり、ｘおよびｙが付された括弧内のシロキサン単位の配列は任意である。）

(In the formula, y is 1 or 2, x + y = 4, and the sequence of siloxane units in parentheses with x and y is arbitrary.)

[Example 2]
After further mixing 0.5 part of 3-glycidoxypropyltrimethoxysilane with two rolls in 100 parts of the silicone adhesive composition obtained in Example 1, the silicone adhesive was prepared in the same manner as in Example 1. The composition was obtained.

[Example 3]
0.5 parts / 2.0 parts of C-25A (platinum catalyst) / C-25B (organohydrogenpolysiloxane) as an addition cross-linking curing agent to 100 parts of the compound prepared in Example 1, respectively. , 0.75 parts of the compound represented by the above formula (i) were mixed with two rolls to obtain a silicone adhesive composition.

[Example 4]
100 parts of organopolysiloxane having an average degree of polymerization of about 6,000, consisting of 99.425 mol% of dimethylsiloxane unit, 0.50 mol% of methylvinylsiloxane unit, and 0.025 mol% of dimethylvinylsiloxane unit, BET ratio. 50 parts of silica (trade name Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.) with a surface area of 300 m ² / g, 11.4 parts of hexamethyldisilazane as a dispersant, and 3 parts of water are kneaded with a kneader and at 170 ° C. Compound-2 was prepared by heat treatment for 2 hours.
With respect to 100 parts by mass of the obtained compound, 0.5 parts / 2.0 parts of C-25A (platinum catalyst) / C-25B (organohydrogenpolysiloxane) as an addition cross-linking curing agent, respectively, and the above formula (i). ) Was mixed with two rolls to obtain a silicone adhesive composition.

[Comparative Example 1]
For 100 parts of the compound-1 obtained in Example 1, 0.5 part / 2.0 parts of C-25A (platinum catalyst) / C-25B (organohydrogenpolysiloxane) as an addition cross-linking curing agent, respectively. The mixture was mixed with two rolls to obtain a silicone adhesive composition.

[Comparative Example 2]
100 parts of organopolysiloxane having an average degree of polymerization of about 6,000, consisting of 99.425 mol% of dimethylsiloxane unit, 0.50 mol% of methylvinylsiloxane unit, and 0.025 mol% of dimethylvinylsiloxane unit, BET ratio. 70 parts of silica (trade name Aerosil 200, manufactured by Nippon Aerosil Co., Ltd.), 16 parts of hexamethyldisilazane, and 4 parts of water with a surface area of 200 m ² / g are kneaded with a kneader and heat-treated at 170 ° C. for 2 hours. Compound-3 was prepared.
For 100 parts of the obtained compound-3, 0.5 parts / 2.0 parts of C-25A (platinum catalyst) / C-25B (organohydrogenpolysiloxane) as an addition cross-linking curing agent, respectively, and the above formula ( 0.25 parts of the compound shown in i) was mixed with two rolls to obtain a silicone adhesive composition.

[Comparative Example 3]
With respect to 100 parts of the compound obtained in Example 1, 0.5 parts / 2.0 parts of C-25A (platinum catalyst) / C-25B as an addition cross-linking curing agent, respectively, and the above formula (i) 5.5 parts of the indicated compound was mixed in two rolls to obtain a silicone adhesive composition.

The plasticity, hardness, total light transmittance, and haze value of the obtained silicone adhesive composition were measured by the following methods. The results are shown in Tables 1 and 2.
[1] Plasticity The obtained silicone adhesive composition was cured under the conditions of 130 ° C./30 minutes, and measured according to JIS K6249.
[2] Hardness The obtained silicone adhesive composition was cured under the conditions of 130 ° C./30 minutes, and the hardness (durometer A) was measured according to JIS K6249.
[3] Transparency Evaluation A 2 mm-thick sheet prepared by pressing the obtained silicone adhesive composition at 130 ° C. and 70 kgf / cm ² for 30 minutes has a total light transmittance and a haze value. Was measured. The measured value is a value obtained by a direct reading haze computer HGM-2 manufactured by Suga Test Instruments Co., Ltd.
[4] Adhesive Strength (A) Polycarbonate As shown in FIG. 1, a polycarbonate test piece 1 (Panlite L1225Y manufactured by Teijin Kasei Co., Ltd.) having a width of 25 mm, a length of 100 mm, and a thickness of 2 mm is used on the surface of the test piece 1. A fluorine-based release tape 2 (NITOFLON (registered trademark) manufactured by Nitto Denko Co., Ltd., No. 903UL; thickness 0.08 mm) is attached so as to cover approximately half of the tape, and a 1.5 mm thick silicone adhesive composition is applied over the tape. An object was placed on the surface and cured at 130 ° C./30 minutes so that the thickness became 1 mm to form the silicone adhesive layer 3. The obtained silicone adhesive layer 3 was subjected to a 180 ° peel test at a speed of 100 mm / min as shown in FIG. 1, and the adhesive strength was measured.
(B) The adhesive strength was measured by the same method as in the case of the above polycarbonate except that a blue plate glass test piece having a width of 25 mm, a length of 100 mm and a thickness of 5 mm was used.

As shown in Tables 1 and 2, it can be seen that the silicone adhesive compositions prepared in the examples have good adhesiveness to polycarbonate and glass and have high total light transmittance.
Therefore, by using the silicone adhesive composition of the present invention, it is possible to process it into a sheet shape by a calendar roll, and by using a vacuum laminator or the like, two glass plates or polycarbonate plates are bonded together for transparency. A composite panel with a high value can be easily produced.

1 Adhesive body (polycarbonate)
2 Fluorine-based release tape 3 Silicone adhesive layer

Claims (5)

(A) The following average composition formula (I)
R ¹ _a SiO _{(4-a) / 2} (I)
(In the formula, R ¹ represents an unsubstituted or substituted monovalent hydrocarbon group independently of each other, but at least two in one molecule are aliphatic unsaturated groups, and a is 1.95 to 2. Represents a positive number of 0.05.)
Represented by 100 parts by mass of organopolysiloxane having a degree of polymerization of 100 or more,
(B) 60 to 150 parts by mass of fumes silica having a BET specific surface area of 300 m ² / g or more ,
(C) 0.1 to 30 parts by mass of an organohydrogenpolysiloxane containing a hydrogen atom bonded to at least two silicon atoms in one molecule.
(D) Hydrosilylation reaction catalyst An organosilicon compound 0.02 containing a catalytic amount and (E) a hydrogen atom bonded to at least one silicon atom in one molecule and having at least one aromatic hydrocarbon skeleton. A silicone adhesive composition comprising up to 5.0 parts by mass. The silicone adhesive composition according to claim 1, wherein the component (B) is a surface-treated fumigant silica having a BET specific surface area of 300 to 500 m ² / g. The silicone adhesive composition according to claim 1 or 2, which is in the form of a sheet, a film, a tape, or a round bar in an unvulcanized state. A bonding method in which the silicone adhesive composition according to any one of claims 1 to 3 is brought into contact with an object to be adhered, and then heat-cured under pressure. The bonding method according to claim 4, wherein the bonded body is glass or polycarbonate.

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