JPH04311765A - Curable organopolysiloxane composition - Google Patents

Abstract

PURPOSE:To obtain a curable organopolysiloxane excellent in tack, adhesiveness and fluidity. CONSTITUTION:(A) 100 pts.wt. organopolysiloxane containing two or more alkenyl groups in one molecule, having 50-200,000cst viscosity (25 deg.C) is blended with (B) 3-20 pts.wt., preferably 5-15 pts.wt. organopolysiloxane shown by the formula [R<1>, R<2> and R<3> are (non)substituted monofunctional hydrocarbon not containing aliphatic unsaturated bond; c, e, f and g are positive integer, d is 0 or positive integer, c+d+e+f=1 and (c+d+e+f)/g is 0.3-4] containing <=30 SiO4/2 units in one molecule and 0.01-0.5mol SiOH group based on 100g component B, (C) an oragnohydrogen polysiloxane containing two or more hydrogen atoms bonded to silicon atom in one molecule in an amount to give 1-20mols hydrogen atom bonded to silicon based on totals of alkenyl groups in the components A and B and (D) a platinum-based catalyst.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable organopolysiloxane composition having good tackiness, adhesion and fluidity, and a cured product obtained by curing the composition.

0002

[Prior Art] Curing reaction by addition reaction of an organopolysiloxane containing a vinyl group bonded to a silicon atom and an organohydrogenpolysiloxane containing a hydrogen atom bonded to a silicon atom in the presence of a platinum catalyst. Curable organopolysiloxanes utilizing the above are conventionally known. However, the cured products of these curable organopolysiloxanes have a drawback in that they have weak adhesion to metals, glass, rubber, plastics, and the like. Therefore, there has been a problem in that the formed cured product is likely to peel off during coating, sealing, potting, etc. of electrical parts. Various adhesion aids have already been proposed for the purpose of improving this drawback (Japanese Patent Publication No. 53-135
No. 08, Special Publication No. 58-26376, Special Publication No. 59-
No. 5219).

0003

[Problems to be Solved by the Invention] However, curable organopolysiloxane compositions containing these adhesion aids need to be cured and bonded in a short time when cured under low temperature conditions and under high temperature conditions. In some cases, sufficient adhesion to the substrate is not achieved and the aforementioned drawbacks remain. In addition, in injection materials, injection materials, and coating materials, when alumina or silica is used to impart thermal conductivity, and/or carbon is used to impart electrical conductivity in high amounts, the fluidity of the composition may be reduced. There is a problem that the temperature decreases, making it difficult to operate in terms of work. Therefore, an object of the present invention is to provide a curable organopolysiloxane composition with improved adhesiveness and fluidity, and a cured product obtained by curing the same.

0004

[Means for Solving the Problems] The present invention provides (a) an organopolysiloxane having two or more alkenyl groups in one molecule, (b) general compositional formula (1):

[Formula 1] (wherein, R1, R2 and R3 represent a substituted or unsubstituted monovalent hydrocarbon group containing no aliphatic unsaturated bond, c, e, f and g are each independently a positive number,
d represents 0 or a positive number, c+d+e+f+g is 1, and (c+d+e+f)/g is 0.3 to 4. ), with 30 SiO4/2 units in one molecule.
(b) an organopolysiloxane containing 0.01 to 0.5 moles of SiOH groups per 100 g of the component; (c) an organohydrohydrogen having two or more hydrogen atoms bonded to silicon atoms in one molecule; The present invention provides a composition containing a polysiloxane and (d) a platinum-based catalyst. The present invention also provides a cured product obtained by curing the composition.

(a) Organopolysiloxane (a)
The organopolysiloxane has at least two alkenyl groups in one molecule and preferably has a viscosity at 25°C of 50 to 200,000 cSt, more preferably 100 to 100,000 cSt. Alkenyl groups are, for example, vinyl groups, allyl groups, 1-
Examples include alkenyl groups having 2 to 8 carbon atoms, such as methyl-2-propenyl group, hexenyl group, and γ-(meth)acryloxypropyl group, preferably vinyl group. Examples of organic groups other than alkenyl groups include alkyl groups such as methyl, ethyl, propyl, and butyl; aryl groups such as phenyl and tolyl; aralkyl groups such as benzyl and β-phenylethyl; Substituted or unsubstituted chloromethyl group, 3,3,3-trifluoropropyl group, etc., in which some or all of the hydrogen atoms of the group are substituted with halogen atoms, etc., having 1 to 10 carbon atoms, preferably having carbon atoms It may contain 1 to 8 monovalent hydrocarbon groups.

[0006] As such organopolysiloxane,
Specifically, the chemical formula below:

[Image Omitted] (In the above formula, p is 2 or 3, s, u and w
is a positive integer, t, v and x are 0 or a positive integer,
s+t, u+v, and w+x each represent a positive integer of 2000 or less. ) can be exemplified.

The organopolysiloxane (a) may have a linear structure or a partially branched structure. Moreover, this organopolysiloxane may be used alone or in a mixture of two or more types.

(b) Organopolysiloxane (b)
The organopolysiloxane is a characteristic component of the present invention, and this component improves the adhesion and fluidity of the composition. In particular, fluidity is significantly improved when a large amount of filler is blended into the composition.

The organopolysiloxane (b) is
It is an organopolysiloxane with a three-dimensional structure having SiO4/2 units as its basic constituent units. (b) In the general compositional formula (1) representing the organopolysiloxane, S
g, which represents the blending ratio of iO4/2 units, is a positive number, and the number of SiO4/2 units contained in one molecule is 30.
or less, preferably 3 to 20. When it exceeds 30, the compatibility with the organopolysiloxane (a) decreases. In addition, it can be used even if it is less than 3, but (b)
The disadvantage is that the proportion of volatile components in the organopolysiloxane increases.

The following chemical formula:

[Chemical formula 3] c, which represents the blending ratio of the units represented by the formula, means that the organopolysiloxane (b) is crosslinked with the organopolysiloxane (a) through an addition reaction, so that bleeding from the cured product is minimized. The number of SiCH═CH2 groups contained in the molecule must be a positive number in order to
A range of 0.05 to 0.20 mol, particularly 0.07 to 0.12 mol is preferred.

[0011] e needs to be a positive number in order to improve tackiness and adhesion, and must be a positive number, that is, a hydroxyl group (SiOH group) bonded to a silicon atom in the molecule.
By containing a specified amount of and adhesive properties. Furthermore, even when a large amount of filler is blended, the fluidity of the resulting composition is significantly improved. Particularly when addition reaction organopolysiloxane compositions are used, for example as injection materials, injection materials and coating materials, alumina or silica for thermal conductivity and/or carbon etc. for electrical conductivity can be added. When a large amount of filler is used, there is a problem that the fluidity of the composition decreases and operation becomes difficult on the work surface, but in the composition of the present invention (b
) The presence of SiOH groups in the components significantly reduces the viscosity of the composition and improves its fluidity. This SiOH group is
(b) In 100g of organopolysiloxane, 0.
0.01 to 0.5 mol, preferably 0.01 to 0.2 mol. If the amount of SiOH groups is less than 0.01 mol, sufficient adhesion and fluidity cannot be obtained;
If the content exceeds 5 moles, curability may be adversely affected or the cured product may have poor heat resistance.

f is a positive number, d is 0 or a positive number,
The sum of c+d+e+f+g is 1. Also, (c+d
The ratio of +e+f)/g is 0.3-4, preferably 0.5-2. (c+d+e+f)/g is 0
．． If it is less than 3, good adhesion cannot be obtained, and if it is more than 4, it becomes substantially difficult to manufacture.

R1 and R2 are usually substituted or unsubstituted monovalent saturated hydrocarbon groups having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, excluding aliphatic unsaturated bonds, such as methyl group, Examples include alkyl groups such as an ethyl group and a propyl group, and aryl groups such as a phenyl group, among which a methyl group is preferred from the viewpoint of production and economy.

R3 is a substituted or unsubstituted monovalent saturated hydrocarbon group, excluding aliphatic unsaturated bonds, usually having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, such as a methyl group or an ethyl group. , a propyl group, a methoxyethyl group, an ethoxyethyl group, etc., among which a methyl group is preferred.

[0015] The blending amount of component (b) is as follows: component (a)
The amount is 3 to 20 parts by weight, more preferably 5 to 15 parts by weight per 100 parts by weight.

(c) Organohydrogenpolysiloxane (c
The organohydrogenpolysiloxane (a) acts as a crosslinking agent for the organopolysiloxane (a) and (b). The structure of the organohydrogenpolysiloxane (c) may be linear, branched, or cyclic, or a mixture thereof. For example, the following general formula:

embedded image (In the above formula, b, c, d, e, f, g, i represent 0 or a positive integer, h represents an integer of 2 or more, and the number of silicon atoms in the molecule is usually 400 or less.)

[C5]

embedded image (In the above formula, R3 represents a hydrogen atom, a methyl group, a propyl group, or a trimethylsiloxy group).

The amount of organohydrogenpolysiloxane (c) to be used is such that 1. 0-20.
The amount is preferably 0 moles, more preferably 1.2
The amount is ~10.0 times the amount by mole.

(d) The platinum-based catalyst (d) The platinum-based catalyst (d) is the platinum-based catalyst (d).
a) and (b) organopolysiloxane, and (c
) must be added as a catalyst for the addition reaction with organohydrogenpolysiloxane.

Examples of platinum-based catalysts include those in which solid platinum is supported on a carrier such as platinum black, alumina, or silica, as well as chloroplatinic acid, alcohol-modified chloroplatinic acid, a complex of chloroplatinic acid and an olefin, and platinum-based catalysts. Examples include platinum or platinum compounds such as complexes with vinylsiloxanes.

When using a platinum-based catalyst, when a solid catalyst is used, it is preferable to use the catalyst in a state where the particle size is small and the specific surface area is large in order to improve dispersibility. Further, when chloroplatinic acid or a complex of chloroplatinic acid and an olefin is used as a catalyst, it is preferable to use these dissolved in an organic solvent such as alcohol, ketone, or ether.

[0021] The amount of catalyst used is usually 0.0000000000000000 in terms of platinum.
It is 1 to 500 ppm. Specifically, for compounds that are compatible with siloxane components, such as chloroplatinic acid,
For solid catalysts such as platinum black, use an amount of 0.1 to 100 ppm (in terms of platinum) based on the total amount of the organopolysiloxanes (a) and (b) and the organohydrogenpolysiloxane (c). 20-500
Preferably, ppm (in terms of platinum) amounts are used.

Other Compounding Agents In addition to the components (a) to (d), fillers may be added to the composition of the present invention, if necessary. As fillers, all those commonly used in addition-type silicone rubber compositions can be used, such as fumed silica, precipitated silica, hydrophobized silica, carbon black, titanium dioxide, ferric oxide, Examples include alumina, zinc oxide, quartz powder, diatomaceous earth, calcium silicate, talc, bentonite, asbestos, glass fiber, and organic fiber, and one or more of these may be used.

The amount of the filler to be used is appropriately selected depending on the type of filler, but it is usually preferably 600 parts by weight or less per 100 parts by weight of the organopolysiloxane (a). Specifically, for example, when using fumed silica, it is preferably 25 parts by weight or less, and in the case of alumina, the range is preferably from 300 to 500 parts by weight.

Furthermore, it is preferable to add an adhesion auxiliary to the composition of the invention, which further improves, in particular, the shear adhesion. Examples of adhesion aids include those having an alkoxysiloxy group disclosed in Japanese Patent Publication No. 53-21026, those having an epoxy-containing hydrovalent group disclosed in Japanese Patent Publication No. 53-13508, and those having an epoxy-containing hydrovalent group disclosed in Japanese Patent Publication No. 53-13508.
Those having an alkoxysiloxy group and an epoxy-containing hydrocarbon group disclosed in Japanese Patent No. 5219 are preferably used. More specifically, but not limited to, the following chemical formula:

[C7]

A silicon compound represented by the following can be exemplified. Moreover, these can also be used by increasing the degree of polymerization as appropriate depending on the purpose.

The organopolysiloxane described above has (a
) per 100 parts by weight of organopolysiloxane 0
．． It is preferably used in a proportion of 5 to 20 parts by weight, particularly 1 to 10 parts by weight. Furthermore, in order to further improve the adhesiveness, for example, trialkylisocyanurate, triallyl trimellitate, or compounds obtained by modifying these with siloxane can be added to the composition of the present invention. More specifically, for example, the following chemical formula:

[Chemical formula 9]

[Chemical formula 10]

[Chemical formula 11]

[Chemical formula 12] The following can be mentioned.

The amount of the above-mentioned compound added is not particularly limited, but is usually about 0.5 to 3 parts by weight per 100 parts by weight of the organopolysiloxane (a). The composition of the present invention may further include a coloring agent, a heat resistant agent,
A flame retardant imparting agent, an addition reaction control agent, a blowing agent, etc. may be appropriately blended.

[0027]

[Example] Example 1 1,3-divinyl-1,1,3,3-tetramethyldisiloxane 46.6g (0.25 mol) and hexamethyldisiloxane 40.6g (0.25 mol)
Ethyl silicate 40 (SiO2
40%) (manufactured by Tama Chemical Industry Co., Ltd.) 150.0
(1.0 mol as SiO2 units) and 5.0 g of para-toluenesulfonic acid were added.

[0028] The mixture was cooled to 0 to 15°C and diluted with water 2
0 g was added dropwise over 1 hour while stirring, and 35 g of water was added 1 hour after the completion of the dropwise addition. Thereafter, the mixture was stirred under reflux at 80°C for 5 hours, and then neutralized with Na2CO3 to obtain an ethanol solution. This solution was replaced with toluene and then separated.
When a 50% by weight toluene solution of organosiloxane was prepared, 125 g of organopolysiloxane was obtained (organopolysiloxane 1).

[(CH
2=CH)(CH3)2SiO1/2]
, [(CH3) 3 SiO1/2] and
The molar ratio of SiO2 units is 0.5:0.5:1.0
Furthermore, the SiOH group in 100 g of resin content is 0.
It contained 0.2 mol and 0.15 mol of SiOC2 H 5 groups. c, d, e, f, and g representing the blending ratio of each unit in the general compositional formula (1) are (c+d+e+f)/
The ratio of SiO in one molecule is 1.2.
4/2 There were 25 units.

Next, linear polydimethylsiloxane
100 parts by weight, (both ends blocked with dimethylvinylsilyl groups, viscosity 5,000 cSt (25°C)), and
Mix 20 parts by weight or more of the above organopolysiloxane 1, remove toluene under reduced pressure, and add fine powder alumina.
350 parts by weight (manufactured by Showa Denko Co., Ltd., product name AS-
40) was added and mixed.

Furthermore, an octanol solution of chloroplatinic acid
0.02 parts by weight (2% by weight as platinum amount) and
Tetravinyltetramethyltetrasiloxane (control agent)
After adding 0.2 parts by weight and mixing, the following chemical formula:

[
Organohydrogenpolysiloxane represented by
Composition 1 was prepared by adding 2.5 parts by weight.

Example 2 Composition 1 prepared in Example 1 had the following chemical formula:

[Chemical 1
Composition 2 was prepared by adding 2.0 parts by weight of an adhesion aid represented by 4.

Example 3 100 parts by weight of linear polydimethylsiloxane,
(Both ends are blocked with dimethylvinylsilyl groups, viscosity 1.0
00 cSt (25°C)) Mix at least 12 parts by weight of organopolysiloxane 1 of Example 1, remove toluene under reduced pressure, and then add 15 parts by weight of acetylene black.
(manufactured by Denki Kagaku Co., Ltd., trade name HS-100) and mixed.

Furthermore, an octanol solution of chloroplatinic acid
0.1 part by weight (2% by weight as platinum amount) and
Tetravinyltetramethyltetrasiloxane (control agent)
After adding 0.1 parts by weight and mixing, the following chemical formula:

Organohydrogenpolysiloxane represented by
2.5 parts by weight and the following chemical formula:

Composition 3 was prepared by adding 2.0 parts by weight of an adhesion aid represented by the following formula.

Example 4 1, used in the preparation of polysiloxane 1 in Example 1
1,3-divinyl-1,1,3,3-tetramethyldisiloxane Instead of 46.6 g, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane
1,1,3,3-tetramethyldisiloxane 18.7
g (0.10 mol) and 1,3-divinyl-1,1
,3,3-diphenyldimethyldisiloxane 10
．． 50 g (0.025 mol) of the organopolysiloxane was carried out in the same manner as in Example 1, except that a mixture of
When a wt % toluene solution was prepared, 110 g of organopolysiloxane was obtained (organopolysiloxane 2).

[(CH
2=CH)(CH3)2SiO1/2]
, [(CH2=CH)(C6H5)(CH3
)SiO1/2], [(CH3)3Si
The molar ratio of O1/2 ] and SiO2 units is 0.
20:0.05:0.5:1.0, and in addition, 0.03 mol of SiOH group and SiO
It contained 0.12 mol of C2H5 groups. c, d, e representing the blending ratio of each unit in the above general formula (1)
, f, and g are the ratios of (c+d+e+f)/g, and 0.
9, and the number of SiO4/2 units in one molecule was 28.

Composition 4 was prepared in the same manner as in Example 3, except that 12 parts by weight of organopolysiloxane 2 was used instead of organopolysiloxane 1.

Comparative Example 1 During the synthesis of organopolysiloxane 1 of Example 1, the amount of water dropped for 1 hour was 9 g, and after the completion of dropping, 35 g of water was added.
and 50 g of toluene were added, and then water and ethanol were gradually removed while stirring at a final temperature of 95°C for 5 hours, followed by neutralization, replacement with toluene, and filtration.
A 50% by weight toluene solution of organopolysiloxane was prepared in the same manner as above, and 120 g of organopolysiloxane was obtained (organopolysiloxane 3).

[(CH
2 = CH) (CH3) 2 SiO1/2],
[(CH3)2SiO1/2] and SiO
The molar ratio of 2 units is 0.5:0.5:1.0,
Furthermore, there are 0.004 SiOH groups in 100g of resin content.
mole, and contained 0.12 mole of SiOC2 H 5 groups. c, d, e, f, and g representing the blending ratio of each unit in the above general formula (1) are 1.1 in the ratio of (c+d+e+f)/g, and SiO4/2 in one molecule
The number of units was 28.

Comparative composition 1 was prepared in the same manner as in Example 1, except that 20 parts by weight of organopolysiloxane 3 was used instead of organopolysiloxane 1.

Comparative Example 2 Comparative Composition 2 was prepared in the same manner as in Example 2, except that 20 parts by weight of Organopolysiloxane 3 from Comparative Example 1 was used.

Comparative Example 3 Comparative Composition 3 was prepared in the same manner as in Example 3, except that 12 parts by weight of Organopolysiloxane 3 of Comparative Example 1 was used.

Regarding the above compositions 1 to 4 and comparative compositions 1 to 3, the physical properties before curing include viscosity and 120°C/
A sheet with a thickness of 2 mm was produced by curing for 60 minutes, and the physical properties after curing were measured for specific gravity, hardness, elongation, and tensile strength according to JIS K6301.

For Compositions 1 and 2 and Comparative Compositions 1 and 2, the shear adhesive strength between aluminum and glass was measured by curing at 120° C. for 60 minutes by preparing test pieces as shown in FIG. 1.

For Composition 3 and Comparative Compositions 3 and 4, the shear adhesive strength due to aluminum was measured by curing at 150° C. for 30 minutes and at 150° C. for 5 minutes by preparing test pieces as shown in FIG. 1. This test piece was made by cutting the ends of aluminum plates or glass plates 1 and 2 with a width of 25 mm into a length of 10 mm.
laminated through a composition 3 with a thickness of 2 mm,
It was produced by curing under the above conditions. The results of each measurement are shown in Table 1.

[0046]

[Table 1]

From Table 1, compositions 1 to 4 had good fluidity and self-leveling properties, while comparative compositions 1 to 3 had poor fluidity and did not have self-leveling properties. In addition, in terms of adhesiveness, Compositions 1 to 4 showed values indicating sufficient adhesive strength in the measurement results of shear adhesive strength, whereas Comparative Compositions 1 and 3 showed a value of (HO1/2) units. was lower than that of Compositions 1 to 4, resulting in insufficient adhesive strength. Although Comparative Composition 2 has sufficient adhesive strength,
Due to the poor fluidity mentioned above, it is difficult to operate and is industrially disadvantageous. In measuring the shear adhesive strength of Compositions 3 to 4 and Comparative Composition 3, the curing conditions were 150°C.
The test was carried out in two ways: 150°C/30 minutes and 150°C/5 minutes, but there was not much difference in the measured values.

[0048]

A curable organopolysiloxane composition and a cured product thereof according to the present invention are a curable organopolysiloxane composition and a cured product thereof having good tackiness, adhesion and fluidity.

[Brief explanation of drawings]

[Figure 1] Test piece used for shear adhesive strength measurement method

[Explanation of symbols]

1 Aluminum plate or glass plate 2　Aluminum plate or glass plate 3. Cured composition

Claims (2)

[Claims] Claim 1: (a) an organopolysiloxane having two or more alkenyl groups in one molecule; (b) general compositional formula (1): [Formula 1] (wherein R1, R2 and R3 are aliphatic Represents a substituted or unsubstituted monovalent hydrocarbon group that does not contain an unsaturated bond, c, e, f and g each independently represent a positive number, d represents 0 or a positive number, c+d+e+f+g is 1, (
c+d+e+f)/g is 0.3-4. ), contains 30 or less SiO4/2 units in one molecule, and contains 0.0 SiOH group per 100g of component (b).
organopolysiloxane containing 1 to 0.5 mol, (c
) A composition containing an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule, and (d) a platinum-based catalyst. 2. A cured product obtained by curing the curable organopolysiloxane composition of claim 1.