JPH0431462A - Curable organopolysiloxane composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having excellent adhesiveness to various substrates such as metal, glass and plastics by mixing a specified organopolysiloxane with a specified organohydrogenpolysiloxane and a hydrosilylation catalyst. CONSTITUTION:The title composition comprises an organopolysiloxane having an average composition formula I [wherein R is a (substituted) hydrocarbon group; and a is 1.0-2.3] and at least two Si-bonded alkenyl groups in the molecular, an organohydrogenpolysiloxane having at least one trialkoxy group bonded to an Si atom through a carbon atom, at least one epoxy-containing organic group and at least three Si-bonded hydrogen atoms in the molecule and at least five Si atoms in the main chain (e.g. a compound of formula II) and a hydrosilylation catalyst (e.g. a product obtained by reacting chloroplatinic acid with 1,3-divinyltetramethyldisiloxane).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to curable organopolysiloxane compositions. Specifically, the present invention relates to a curable organopolysiloxane composition that exhibits excellent adhesion to various substrates such as metal, glass, and plastic.

[Prior Art] An organopolysiloxane composition that is cured by a hydrosilylation reaction has the characteristic that no reaction by-products are produced and the curing proceeds rapidly to the deep part.
It is used in a wide range of fields, including adhesives, botting materials and coating materials for electrical and electronic components, and release coating materials for paper and film.

However, this type of organopolysiloxane composition generally has a problem of poor adhesion to other materials. When organopolysiloxane compositions with insufficient adhesive properties are used as botting materials and coating materials for electrical and electronic components, they tend to peel off, allowing moisture to enter and reducing adhesive strength.

In order to solve these problems, many methods have been proposed to improve the adhesion of this type of organopolysiloxane composition by adding various organosilanes or organosiloxanes as adhesion-imparting components. has been done. However, in organopolysiloxane compositions containing organosilane as an adhesion-imparting component, the organosilane volatilizes during heat curing, resulting in insufficient adhesion or deterioration of the physical properties of the cured product. Organopolysiloxane compositions containing organopolysiloxane as an adhesion-providing component contain 3 to 6 silicon atoms, an epoxy group and/or an ester group, and a silicon-bonded hydrogen atom. An organopolysiloxane composition having a crosslinking agent component is known (see JP-A-50-39345).However, this composition does not adhere well to metals such as glass, aluminum, and iron. However, polybutylene terephthalate (PBT) has recently come into use.
, 6 nylon, polyphenylene sulfide (PR5
) and other engineering plastics had the disadvantage of poor adhesion.

[Problems to be Solved by the Invention] As a result of intensive research aimed at solving the problem described above, the present inventors found that a curable organopolysiloxane composition containing a specific organopolysiloxane as a crosslinking agent component The present invention was achieved by discovering that it exhibits strong self-adhesion not only to glass but also to plastic. That is, an object of the present invention is to provide a curable organopolysiloxane composition that exhibits excellent adhesion to a wide variety of substrates such as metals, glass, and plastics.

[Means for Solving the Problems and Their Effects] The present invention has the following features: (A) average compositional formula Ra5lO+a~a+z2 (in the formula, R
is a substituted or non-W-substituted monovalent hydrocarbon group, a is 1.0 to 2
(B) an organopolysiloxane having at least two silicon-bonded alkenyl groups in one molecule; (B) a trialkoxy group bonded to a silicon atom through a carbon atom in one molecule; An organohydrodiene polysiloxane containing one or more silyl groups, one or more epoxy group-containing organic groups, two or more silicon-bonded hydrogen atoms, and the number of silicon atoms in the main chain is 5 or more, and (C) hydrosilyl The present invention relates to a curable organopolysiloxane composition comprising a catalyst for chemical reaction.

The organopolysiloxane (A) component used in the present invention is a main component of the composition of the present invention, and must have at least two silicon-bonded alkenyl groups in one molecule. In the above formula, R is a methyl group, an ethyl group, a propyl group, or a butyl group.

Alkyl groups such as hexyl and octyl; alkenyl groups such as vinyl, allyl and hexenyl; aryl groups such as phenyl; substituted hydrocarbon groups such as 3,3゜3-trifluoropropyl; These are exemplified monovalent hydrocarbon groups, and a is a number from 1.0 to 2.3. The molecular structure of this organopolysiloxane may have a linear or branched siloxane skeleton.Although its degree of polymerization is not particularly limited, it usually has a viscosity of 1 at 25°C.
A range of 0 to 1,000,000 centivoices is used.

Component (B) used in the present invention is a crosslinking agent for the organopolysiloxane of component (A), and is an essential component to exhibit excellent adhesiveness to other base materials. contains one or more trialkoxysilyl groups bonded to a hydrogen atom via a carbon atom, one or more epoxy group-containing organic groups, and two or more silicon-bonded hydrogen atoms, and the number of silicon atoms in the main chain is 5. The organohydrodiene polysiloxane is as described above.

Here, in order for the composition of the present invention to exhibit adhesive properties, the organic group containing a trialkoxysilyl group and an epoxy group bonded to a silicon atom through a carbon atom must be present in the organohydrodiene polysiloxane component (B). There must be one or more of each in one molecule. Examples of such trialkoxysilyl groups include trialkoxysilyl groups such as trimethoxysilyl group, triethoxysilyl group, triisopropoxysilyl group, and tributoxysilyl group, and methylene groups.

Organic groups bonded to silicon atoms via alkylene groups are exemplified by ethylene, propylene, and butylene groups, and epoxy group-containing organic groups are exemplified by glycidoxyprobyl and epoxycyclohexylethyl groups. There are 81 groups.

In addition, in order for the composition of the present invention to form a network structure, (
B) It is necessary that one molecule of component contains three or more silicon-bonded hydrogen atoms.

In addition to these organic groups, examples of organic groups bonded to silicon atoms include the same monovalent hydrocarbon groups as exemplified for the organopolysiloxane of component (A) described above. Only one type of organic group may be present in one molecule, and
Two or more types may be mixed.

Furthermore, the organohydrodiene polysiloxane of component (B) needs to have 5 or more silicon atoms in one molecule. When the number is 4 or less, the reactivity of silicon-bonded hydrogen atoms deteriorates due to steric hindrance, etc.
This is because the curing of the wood-based acid compound may be insufficient, resulting in a decrease in adhesive strength or poor curing. Further, when it is necessary to complete the curing reaction, it is desirable that an average of four or more silicon-bonded hydrogen atoms exist in one molecule.

Examples of such component (B) include the following compounds.

(m + p is an integer of 1 or more, n is O or an integer of 1 or more, q is an integer of 3 or more.) (r, u are an integer of 1 or more, S is ○ or an integer of 1 or more,
t is an integer of 3 or more. ) Me2Si[l(MezSiO) v(MeHSiO)
,,SiHe2C)12c)IgSi(OR)sCs
HqOCH2CHCHz \1 (V is an integer of 0 or 1 or more, W is an integer of 3 or more.) Such organohydrodiene polysiloxane is
For example, an alkenyl group-containing trialkoxysilane and an alkenyl group-containing epoxy compound are added to methylhydrodiene polysiloxane, which is well known as a crosslinking agent for organopolysiloxanes that is cured by a normal hydrosilylation reaction, in the presence of a hydrosilylation reaction catalyst. It can be easily manufactured by adding parts. Here, examples of the alkenyl group-containing trialkoxysilane include vinyltrialkoxysilane, allyl)-realkoxysilane, and hexenyltrialkoxysilane. Examples of the alkenyl group-containing epoxy compound include allyl glycidyl ether. The molecular structure of component (B) used in the present invention may include a linear structure, a network structure, or a three-dimensional structure, and may be a single polymer, a copolymer, or a combination of two or more of these. Mixtures can also be used. Also,
The degree of polymerization is usually determined by a viscosity of 0.5 to s at 25°C.
o, oo.

Within the centiboise range, preferably 1 to 10.0
Those within the range of 00 centimeter voices are used.

In addition, the blending amount is such that the molar ratio of silicon-bonded hydrogen atoms in this component to silicon-bonded alkenyl groups in component (A) is preferably in the range of 0.5/1 to 5/1. Usually, the amount of component (A) is 100ji! 0.1 to 10. Within the range of parts by weight.

As the catalyst for the hydrosilylation reaction of component (C), all conventionally known transition metal catalysts exhibiting hydrosilylation catalytic activity can be used. Specifically, examples include chloroplatinic acid, alcohol-modified chloroplatinic acid, complexes of chloroplatinic acid and olefins, complexes of platinum or chloroplatinic acid and vinyl siloxane, platinum supported on alumina, silica, carbon black, etc., and platinum black. Examples include platinum-based catalysts such as those exemplified by, palladium catalysts such as tetrakis(triphenylphosphine)palladium, and rhodium catalysts. Among these, a complex catalyst of platinum or salt platinum acid and vinylsiloxane is preferred from the viewpoint of high activity and compatibility with components (A) and (B). The blending amount of component (C) is usually 100% of the organopolysiloxane of component (A).
It is within the range of 0.000001 to 0.1 part by weight, preferably 0.00005 to 0.1 part by weight in terms of platinum.
It is within the range of 0.01 parts by weight. Furthermore, the platinum equivalent weight is
In the case of transition metals other than platinum, it means the weight calculated assuming that platinum has the same number of atoms as the transition metal to be blended.

The composition of the present invention is an organopolysiloxane composition consisting of the above-mentioned components (A) to (C). The treated fine powder silica contains at least two silicon-bonded hydrogen atoms per molecule to adjust the molar ratio of silicon-bonded hydrogen atoms in this component to silicon-bonded alkenyl groups in component (A). methylhydrodienepolysiloxane, creep hardening inhibitor, phenylbutynol, storage stabilizer such as triallylisocyanutate, polymers other than organopolysiloxane, heat resistant agent, flame retardant, quartz powder, diatomaceous earth, anthracite calcium, There is no problem in blending glass fiber or the like as long as it does not impair the purpose of the present invention.

The composition of the present invention can be easily obtained by uniformly mixing the above components (A) to (C).

To cure the composition of the present invention, it can be cured by leaving it at room temperature, or it can be heated to accelerate curing. It is preferable to heat and harden at a temperature of about 150°C to 150°C.

The composition of the present invention as described above has excellent adhesion to various substrates made of various materials, and is therefore extremely useful as an adhesive, a botting agent for electrical/electronic parts, or a coating agent.

[Example] Next, the present invention will be explained by referring to an example. In the examples, parts are parts by weight, viscosity is a value at 25°C, Cp is centivoise, and % is weight %. In the Examples, the adhesion test and the measurement of adhesive strength were carried out in accordance with the tensile shear test specified in ASTM standard D 1002-53T.

Example 1 Both ends of the molecular chain are blocked with dimethylvinyl shirogishi groups,
Dimethylpolysiloxane 100 with a viscosity of approximately 2000 cp
After uniformly mixing 20 parts of fine powdered silica with a specific surface area of about 200 mg/g that had been surface-hydrophobized with hexamethyldisilazane, the average molecular formula was MesSiO(MeSiO) (MezSiO)s (
HeSiO) ()leHsiO) 6S 1cell!
(CHz)30cH2cHcH2CH2CHaSi(O
Me)a (A)\1 Organohydrodiene polysiloxane 3.
0g and 3.5-dimethyl-3-hexynol 0.01g
was added and mixed uniformly. Furthermore, 1,3-divinyltetramethyldisiloxane and chloroplatinic acid (H2Ptc
A reaction product containing a platinum complex coordinated with 1,3-divinyltetramethyldisiloxane (platinum metal concentration: 4.3%) obtained by reaction with 1,3-divinyltetramethyldisiloxane (platinum metal concentration: 4.3%) 0.015
g were mixed to obtain a curable organopolysiloxane composition. These compositions can be applied to aluminum plates, iron plates, Bakelite plates, epoxy glass plates (epoxy resin plates reinforced with glass fibers), polybutylene terephthalate (PBT), etc.
) was sandwiched between two test pieces each consisting of a plate and a glass plate, and was cured in an open heating at 120°C for 1 hour, so that the two test pieces were integrated via the cured product of the organopolysiloxane composition. A test specimen was obtained. Next, this test piece was subjected to a tensile test aM (Tensilon) to measure its adhesive strength. The results of these measurements are shown in Table 1.

For comparison, instead of the organohydrodiene polysiloxane represented by formula (^) as the crosslinking agent in the above
The adhesive strength of an organopolysiloxane composition prepared in the same manner as above except that 0.87 g of methylhydrodiene polysiloxane represented by the formula '()leHSiO)n- was blended was measured in the same manner as above. The results are also listed in Table 1.

Table 1 Example 2 Both ends of the molecular chain are blocked with dimethylvinylsiloxy groups,
Dimethylpolysiloxane 58B with a viscosity of approximately 2700 cp
I5. It consists of trimethylsiloxy units, dimethylvinylsiloxy units, and Si○4/□ units, and has a viscosity of about 10
After thoroughly mixing 13 parts of cs methyl polysiloxane, 17 parts of quartz powder with an average particle size of about 5 microns, and 12 parts of fine powdered silica with a specific surface area of about 200 mg/g, the surface of which has been surface-hydrophobized with hexamethyldisilazane, 6.8 parts of the organohydrodiene polysiloxane represented by formula (A) used in Example 1 and 0.02 part of the reaction product containing the platinum complex used in Example 1 were uniformly mixed. This composition can be applied to aluminum plates, copper plates, iron plates, nickel plates, brass plates,
The test pieces were sandwiched between two test pieces each: Bakelite plate, epoxy glass plate (epoxy resin plate reinforced with glass fiber), PBT plate, and 6-nylon plate, and these were heated at 120°C for 1 hour and cured in an open environment. A test specimen was obtained in which the two test pieces were integrated via the cured product of the organopolysiloxane composition. Next, this test specimen was placed in a tensile tester (
Tensilon) to measure the adhesive strength and adhesive condition.

As a comparative example, the formula (A
) instead of the organohydrodiene polysiloxane represented by the formula % 4.
The same adhesion test as above was conducted on an organopolysiloxane composition prepared in the same manner as above with the addition of 9 g. These measurement results are also listed in Table 2.

Table 2 O Cohesive failure rate is 95% or more (fractured in the organopolysiloxane composition cured product layer) △ Cohesive failure rate is 5-5
It was 95%.

× Interfacial peeling (peeling at the interface between the cured organopolysiloxane composition layer and the base material) Example 3 In Example 2, instead of the organohydrodiene polysiloxane represented by formula (A), the formula % formula % () Organohydrodiene polysiloxane represented by 4.
0g and an organohydrodiene polysiloxane with the formula % () 2.
A curable organopolysiloxane composition was prepared by adding 0 g. This composition was tested for adhesion to PBT and 6-nylon in the same manner as in Example 2. As a result, all adhesive states were cohesive failure.

For comparison, instead of the organohydrodiene polysiloxane represented by formula (C) above, organohydrodiene polysiloxane represented by the formula % formula % () [2.
An organopolysiloxane composition was produced in the same manner as above except that Og was blended.

An adhesion test was conducted on this composition in the same manner as above. As a result, the adhesive state was all interfacial failure.

For comparison, instead of the organohydrodiene polysiloxane represented by formula (C) above, organohydrodiene polysiloxane 2.
An organopolysiloxane composition was produced in the same manner as above except that 0 g was added, and the adhesion test of this composition to PBT and 6-nylon was conducted in the same manner as in Example 2. As a result, all adhesive states were interfacial peeling.

[Effect of the invention] The curable organopolysiloxane composition of the invention has (A
) to (C), and especially contains a specific organohydrodiene polysiloxane as component (B), so it is a metal or glass.

It is characterized by excellent adhesion to various base materials such as plastics.

Claims (1)

[Claims] 1(A) Average compositional formula R_aSiO_(_4_-_a_)
_/_2 (wherein R is a substituted or unsubstituted monovalent hydrocarbon group, a is a number from 1.0 to 2.3), and at least two silicon-bonded alkenyl atoms are present in one molecule. organopolysiloxane having groups, (B) one or more trialkoxysilyl groups bonded to silicon atoms via carbon atoms, one or more epoxy group-containing organic groups, and three or more silicon-bonded hydrogen atoms in one molecule; A curable organopolysiloxane composition comprising: an organohydrogenpolysiloxane having 5 or more silicon atoms in its main chain; and (C) a catalyst for a hydrosilylation reaction. 2. The curable organopolysiloxane composition according to claim 1, wherein the hydrosilylation reaction catalyst constituting component 2(C) is a platinum-based catalyst. 3. The curable organopolysiloxane composition according to claim 2, wherein the platinum-based catalyst is a complex catalyst of platinum or chloroplatinic acid and alkenylsiloxane. 4. The curable organopolysiloxane composition according to claim 1, wherein component (B) has four or more silicon-bonded hydrogen atoms.