JPH0625534A - Curable polyorganosiloxane composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, comprising an alkenyl group- containing polysiloxane, a polyorganohydrogensiloxane, a platinum-based catalyst and a specific silylated amine compound, preservable at room temperature for a long period and rapidly curable by heating. CONSTITUTION:This polymer composition is obtained by blending (A) a polyorganosiloxane having g >=0.05mol% alkenyl groups in the whole organic groups bound to silicon atom with (B) a polyorganohydrogensiloxane having >=2 hydrogen atoms bound to silicon atom based on one molecule, <=1 hydrogen atom based on l silicon atom and other groups which are 1-6C alkyl, phenyl and 3,3,3-trifluoropropyl groups, etc., bound to the silicon atom in an amount so as to provide 0.2-5 SiH groups based on 1 alkenyl group in the component (A), (C) a platinum-based catalyst in an amount of 1-500ppm based on the component (A) and (D) a silylated amine compound of the formula {R<1> is 1-4C alkyl; R<2> is 2-6C alkylene; (n) and (m) are 0-2; [(n)+(m)]>=2} in an amount of 0.1-50mol based on 1mol platinum.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an addition reaction type curable polyorganosiloxane composition having good long-term storage stability at room temperature.

[0002]

2. Description of the Prior Art Addition reaction type curable compositions containing alkenyl group-containing polyorganosiloxanes, polyorganohydrogensiloxanes and platinum catalysts as main components have been well known. However, when these compositions are stored at room temperature for a long period of time, they cause disadvantages such as thickening and gelation. Therefore, practically, there has been a demand for a composition that can be stably stored at room temperature for a long time in a mixed form of the components and that can be cured only when heated.

Therefore, many compositions containing a reaction retarder for imparting storage stability at room temperature have been proposed. Examples of such a reaction retarder include organic phosphorus compounds and US Pat.
No. 181, a benzotriazole compound, No. 3344
No. 111 proposes a nitrile compound, No. 3383556 proposes a halocarbon compound, No. 3445420 proposes an acetylene compound, and No. 3453234 proposes a sulfoxide compound. Also, US Pat. No. 318
No. 8299 has pyridine, picolines, and No. 38673.
No. 43, amine compounds such as 2,2'-dipyridyl,
No. 4,584,361 discloses amine compounds such as N, N, N ', N'-tetramethylethylenediamine. Further, for the same purpose, JP-B-3-27588 discloses the use of monoalkylamine or N, N-dialkylalkylenediamine.
Japanese Patent Laid-Open No. 95267 discloses the combined use of monoalkylamine and acetylene alcohol.

However, it is very difficult for any of the above reaction retarders to have both curability and stability. Particularly, pyridine and dipyridyl show good behavior in terms of stability, but over a long period of time. Coexistence with a platinum compound has a drawback that the curability is significantly reduced. The most common and effective acetylene alcohol among the acetylene compounds has a problem that when the addition amount is increased for the purpose of improving stability, the surface of the cured product is wrinkled. Further, N, N, N ', N'-tetramethylethylenediamine does not have a sufficient suppressing effect, and it is necessary to add a relatively large amount in practical use. Therefore, the activity of the platinum compound is reduced by long-term storage. In order to eliminate such drawbacks, there is a demand for a reaction retarder which works effectively even in a small amount.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to incorporate the effective amount of the reaction retarder in a small amount so that the catalyst curing which is recognized in the system containing a large amount of the retarder as in the above-mentioned prior art can be achieved. It is an object of the present invention to provide an addition reaction type polyorganosiloxane composition which is excellent in storage stability at room temperature and which can be easily cured by heating without causing deterioration over time.

[0006]

Means for Solving the Problems As a result of repeated studies to solve the above problems, the present inventors have substituted a part or all of amino active hydrogen atoms of a specific diamine with a trialkylsilyl group. As a result, they have found that a reaction retarder that works effectively in a small amount can be obtained, and completed the present invention.

That is, the present invention provides the following component (A),
It relates to a curable polyorganosiloxane composition containing (B), (C) and (D). (A) Polyorganosiloxane in which 0.05 mol% or more of all organic groups bonded to silicon atoms are alkenyl groups; (B) Polyorganohydrogensiloxane, in which the hydrogen atoms bonded to the silicon atoms are 1 2 per molecule
More than one and less than or equal to one per silicon atom,
The other group bonded to the silicon atom is selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenyl group and a 3,3,3-trifluoropropyl group. The amount of the hydrogen atom bonded to the silicon atom is 0.2 to 5 per 1 alkenyl group of 1);
500 ppm; and (D) the general formula ^{_{(R 1 3 Si) n NH}} 2-n R 2 NH 2-m (SiR
Silylated amine compound represented by ¹ ₃ ) _m [wherein R ¹ represents an alkyl group having 1 to 4 carbon atoms;
² represents an alkylene group having 2 to 6 carbon atoms; n and m each represent a number of 0 to 2, and n + m is 2 or more].
0.1 to 50 mol per mol of platinum.

The alkenyl group-containing polyorganosiloxane of component (A) used in the present invention has an alkenyl group directly bonded to a silicon atom, and the siloxane skeleton may be linear or branched, or a mixture thereof. May be Examples of the alkenyl group include vinyl, allyl, 1-butenyl, 1-hexenyl, etc., but the vinyl group is preferable from the viewpoint of ease of synthesis. As a substituent bonded to a silicon atom other than an alkenyl group, an alkyl group such as methyl, ethyl, propyl, butyl, hexyl and dodecyl; an aryl group such as phenyl; an aralkyl group such as 2-phenylethyl, 2-phenylpropyl; Substituted hydrocarbon groups such as chloromethyl and 3,3,3-trifluoropropyl are exemplified. Of these, a methyl group is most preferred because it is easy to synthesize, has a degree of polymerization necessary for maintaining good physical properties after curing, and retains a low viscosity before curing.
When the composition after curing is required to have cold resistance and special optical properties, a phenyl group is contained in the molecule, and when oil resistance is required, a 3,3,3-trifluoropyropyr group is contained. It can be arbitrarily selected.

Further, the component (A) serves as a base polymer of an addition reaction type curable polyorganosiloxane, and 0.05 mol% or more of all organic groups bonded to silicon atoms are alkenyl groups. is necessary. The viscosity is not particularly limited, but it is preferably 20 cP or more at 25 ° C., and particularly preferably 700 cP or more, especially for a rubber-like elastic body having good mechanical properties, and 2,000 to 6,000,000cP
Is particularly preferable, but among them, those having a fluidity of 250,000 cP or less are desirable for applications requiring fluidity before curing.

The polyorganohydrogensiloxane of the component (B) used in the present invention is crosslinked by the addition reaction with the component (A) to make the composition into a rubber elastic body or a gel, so that one molecule is used. It is an essential component having two or more hydrogen atoms bonded to one silicon atom and one or less hydrogen atom bonded to each silicon atom. The organic group bonded to a silicon atom other than a hydrogen atom is a group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenyl group and a 3,3,3-trifluoropropyl group, but is easy to synthesize. From the viewpoint, a methyl group is most preferable. As such a polyorganohydrogen siloxane, the siloxane skeleton may be linear, branched or cyclic.

Specific examples of the component (B) include the following. a. Branched polyorganohydrogensiloxane consisting of (CH ₃ ) ₂ HSiO _1/2 and SiO ₂ units b. Formula (I)

[0012]

[Chemical 1]

(Where p is 3 to 100 and q is 0 to 100)
Represents an integer of), a linear polyorganohydrogensiloxane represented by the formula; c. Formula (II)

[0014]

[Chemical 2]

(Wherein p is 1 to 100 and q is 0 to 100)
Represents an integer) of the linear polyorganohydrogensiloxane.

Component (B) is blended in such an amount that one alkenyl group in component (A) contains 0.2 to 5 hydrogen atoms bonded to silicon atoms in component (B). Is.
If you want to obtain a gelled cured product with buffering property,
The range of 0.8 is preferable, and the range of 0.8 to 5 is preferable when it is desired to obtain a rubber-like elastic body. 0.2 hydrogen atoms
If the number is less than the above, the crosslinking density will be too low, whereby the curing of the composition will not proceed sufficiently and the desired physical properties such as fluidity after curing will not be obtained, which is not preferable. Also, if the number of hydrogen atoms exceeds 5, it easily foams during curing,
The heat resistance after curing is lowered, which is not preferable.

The component (C) used in the present invention is a hydrosilylation catalyst, and the platinum-based catalyst used here is Lamoreau's catalyst (platinum-octanol complex, US Pat. No. 47).
43377), Ashby's catalyst (platinum-vinyl group-containing cyclic siloxane complex, U.S. Pat. No. 4,288,834).
No. 5), Karstedt's catalyst (platinum-vinyl group-containing disiloxane complex, US Pat. No. 3,814,730), and the like.

The blending amount of the component (C) in the present invention is 1 to 500 ppm as platinum with respect to the component (A), and when considering the curability and the physical properties after curing, it is 3 to 25 ppm.
0 pp is preferred.

The silylated amine compound as the component (D) used in the present invention is a characteristic component in the present invention. It acts as a retarder of the hydrosilylation reaction and imparts excellent storage stability to the composition of the present invention without impairing its excellent curability. In the above general formula, R ¹ has 1 to 4 carbon atoms.
An alkyl group, which may be linear or branched, methyl,
Ethyl, propyl, isopropyl, tert-butyl and the like are exemplified, and methyl is preferable because of easy synthesis.
R ² is an alkylene group having 2 to 6 carbon atoms, and examples thereof include ethylene, trimethylene, tetramethylene, pentamethylene, and hexamethylene, and ethylene is preferable because raw materials are easily available. 2 present in such alkylene groups
Of the total of 4 amine-active hydrogen atoms in each amino group, at least 2 are substituted with trialkylsilyl groups. That is, n + m is 2 to 4, and n = m = 1 is preferable because synthesis is easy.

Specific examples of the silylated amine compound include N, N'-bis (trimethylsilyl)
Ethylenediamine, N, N'-bis (triethylsilyl) ethylenediamine, N, N'-bis (propyldimethylsilyl) ethylenediamine, N, N'-bis (isopropyldimethylsilyl) ethylenediamine, N, N '
-Bis (tert-butyldimethylsilyl) ethylenediamine, N, N'-bis (trimethylsilyl) propylenediamine, N, N'-bis (triethylsilyl) propylenediamine, N, N'-bis (trimethylsilyl) tetramethylenediamine, N , N'-bis (trimethylsilyl) pentamethylenediamine, N, N'-bis (trimethylsilyl) hexamethylenediamine, N, N, N'-
Tris (trimethylsilyl) ethylenediamine, N,
N, N'-tris (triethylsilyl) ethylenediamine, N, N, N'-tris (trimethylsilyl) propylenediamine, N, N, N'-tris (triethylsilyl) propylenediamine, N, N, N ', N' -Tetrakis (trimethylsilyl) ethylenediamine, N, N,
N ', N'-tetrakis (triethylsilyl) ethylenediamine, N, N, N', N'-tetrakis (trimethylsilyl) propylenediamine, N, N, N ', N'-
Tetrakis (triethylsilyl) propylenediamine,
N, N-bis (trimethylsilyl) ethylenediamine,
N, N-bis (triethylsilyl) ethylenediamine,
Examples of such compounds include N, N-bis (trimethylsilyl) propylenediamine and N, N-bis (triethylsilyl) propylenediamine.

The amount of the component (D) to be added is 0.1 to 50 mol per 1 mol of platinum, and 0.5 to 3 mol is necessary for sufficient curability and storage stability. preferable. The component (D) may be added as it is, or may be diluted with an organic solvent such as toluene or xylene and added.

The component (D) can be easily obtained by reacting a corresponding alkylenediamine with a disilazane such as hexamethyldisilazane or a chlorosilane such as trimethylchlorosilane.

The component (D) may be used alone as it is, or may be used in combination with acetylene alcohol in order to further enhance the effect as an inhibitor. Examples of the acetylene alcohol include 3-methyl-1-butyn-3-ol, 3-phenyl-1-butyn-3-ol, 1-ethynyl-1-hexanol,
3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol and the like can be mentioned. The compounding amount of acetylene alcohol is 1 to 1 mol of platinum.
The amount is preferably in the range of 1,000 mol, more preferably 40 to 200 mol in view of curability, stability, physical properties after curing and the like.

In the composition of the present invention, in addition to the components (A) to (D), if necessary, an inorganic filler is appropriately added so that the composition has a flowability suitable for the intended use and a hardness after curing. , Tensile strength, elongation, modulus, etc. can be obtained. Such inorganic fillers are usually fumed silica, silica aerosol, precipitated silica, ground silica, diatomaceous earth, iron oxide, zinc oxide, titanium oxide, calcium carbonate,
Examples include magnesium carbonate, zinc carbonate, carbon black and the like. The amount of these fillers used is arbitrary as long as the object of the present invention is not impaired. If necessary, suitable pigments, dyes, adhesion aids, antifungal agents, heat resistance improvers, flame retardants or antioxidants can be added. further,
In carrying out the present invention, the composition of the present invention may be used after being dispersed or dissolved in a suitable organic solvent such as toluene or xylene depending on the use.

[0025]

The reaction retarder used in the present invention has a silyl group introduced into the diamine, so that a small amount of
The unexpected effect of effectively suppressing the action of the platinum catalyst at room temperature and not inhibiting the curing reaction by heating was obtained.

By using such a reaction retarder, the curable polyorganosiloxane composition of the present invention is
It can be stored at room temperature for a long period of time, and when it is heat-cured, the temperature dependence of the curing is significantly larger than that of conventional compositions, so it cures quickly by heating and even when hot-air curing is performed at high temperature It cures quickly from the surface to the inside without wrinkles or irregularities. Therefore, if the curable polyorganosiloxane composition of the present invention is used, the workability can be improved, the process of the product using the curable polyorganosiloxane can be shortened, and the working time for handling these can be extended. be able to.

The curable polyorganosiloxane composition of the present invention includes potting agents and coating agents in the electric and electronic industries as well as dipping agents in the general industry, molding rubbers, molding materials, coating agents for peeling and dental use. It is suitable for use in a wide range of applications such as addition reaction type silicone rubber or silicone gel for impression materials, and its utility is great.

[0028]

The present invention will be described below with reference to examples. The scope of the invention is not limited by these examples. In the examples and comparative examples, all parts and% are parts by weight and% by weight. Also, the viscosity is 25
It is the viscosity at ° C.

Example 1 100 parts of polydimethylsiloxane having a molecular chain end blocked with dimethylvinylsilyl groups and a viscosity of 10,000 cP,
(CH ₃ ) ₂ HSiO _1/2 unit 67 mol% and SiO ₂ unit 33 mol% 1.0 part polymethyl hydrogen siloxane, 0.20 part of Karstedt's catalyst solution containing 0.5% platinum , N, N'-bis (trimethylsilyl) ethylenediamine in 0.1% toluene solution 0.
52 parts (molar ratio to platinum atom: 0.5) were uniformly mixed to obtain a composition.

Regarding the storage stability of the obtained composition,
The change in viscosity after storage at 50 ° C. for 7 days was expressed as a magnification of the initial viscosity and evaluated. As for the curability, the sample was placed on a hot plate at 150 ° C. so as to have a thickness of about 2 mm, and the gelling time of the sample was measured. The gelation time at 150 ° C. of the sample stored at 50 ° C. for 7 days was also measured in the same manner.

Example 2 The experiment of Example 1 was repeated except that 0.0052 parts of N, N'-bis (trimethylsilyl) ethylenediamine was not diluted with the solvent.

Example 3 The experiment of Example 1 was repeated except that 3.1 parts of a 1% toluene solution of N, N'-bis (trimethylsilyl) ethylenediamine was added.

Example 4 Example 1 was repeated except that 0.70 parts of a 1% toluene solution of N, N, N'-tris (trimethylsilyl) ethylenediamine was added in place of N, N'-bis (trimethylsilyl) ethylenediamine. The experiment was repeated.

Example 5 In place of N, N'-bis (trimethylsilyl) ethylenediamine, 0.89 parts of a 1% toluene solution of N, N, N ', N'-tetrakis (trimethylsilyl) ethylenediamine was added. The experiment of Example 1 was repeated.

Example 6 Instead of N, N'-bis (trimethylsilyl) ethylenediamine, N, N, N'-tris (triethylsilyl) propylenediamine in 0.1% toluene solution 1.0
The experiment of Example 1 was repeated except that 6 parts were added.

Comparative Example 1 Implementation was carried out except that 0.30 parts of 0.1% toluene solution of N, N, N ', N'-tetramethylethylenediamine was added in place of N, N'-bis (trimethylsilyl) ethylenediamine. The experiment of Example 1 was repeated.

Comparative Example 2 The experiment of Comparative Example 1 was repeated except that the amount of N, N, N ', N'-tetramethylethylenediamine added was 0.30 parts as a 1% toluene solution.

Comparative Example 3 The experiment of Comparative Example 1 was repeated except that the amount of N, N, N ', N'-tetramethylethylenediamine added was 0.030 parts.

Comparative Example 4 Instead of N, N'-bis (trimethylsilyl) ethylenediamine, N, N-dimethylethylenediamine was added in an amount of 0.
The experiment of Example 1 was repeated except that 022 parts was added.

The results of Examples 1 to 6 and Comparative Examples 1 to 4 are summarized in Table 1. As is clear from Table 1, the curable polyorganosiloxane composition of the present invention using a trialkylsilylated diamine as a reaction retarder is
Even after long-term storage, the viscosity does not increase and storage stability is excellent. Furthermore, it cures in a short time by heating at 150 ° C., and its curability hardly changes even after long-term storage.
In contrast, the composition of Comparative Example using a dialkyl that is not trialkylsilylated is poor in storage stability when the addition amount is small, and the viscosity increase rate after long-term storage is large even when the addition amount is increased. In addition, the curability after storage for a long time is low. The compositions of the examples according to the present invention were colorless and transparent immediately after preparation, and those with a large amount of the reaction retarder added had a light brown color after the storage test at 50 ° C., but were still transparent. Met. On the other hand, the samples of Comparative Examples were neither transparent to brown nor opaque to brown after the above storage test.

[0041]

[Table 1]

Claims (1)

[Claims] 1. A curable polyorganosiloxane composition comprising the following components (A), (B), (C) and (D). (A) Polyorganosiloxane in which 0.05 mol% or more of all organic groups bonded to silicon atoms are alkenyl groups; (B) Polyorganohydrogensiloxane, in which the hydrogen atoms bonded to the silicon atoms are 1 2 per molecule
More than one and less than or equal to one per silicon atom,
The other group bonded to the silicon atom is selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenyl group and a 3,3,3-trifluoropropyl group. The amount of the hydrogen atom bonded to the silicon atom is 0.2 to 5 per 1 alkenyl group of 1);
500 ppm; and (D) the general formula ^{_{(R 1 3 Si) n NH}} 2-n R 2 NH 2-m (SiR
Silylated amine compound represented by ¹ ₃ ) _m [wherein R ¹ represents an alkyl group having 1 to 4 carbon atoms;
² represents an alkylene group having 2 to 6 carbon atoms: n and m each represent a number of 0 to 2, and n + m is 2 or more].
0.1 to 50 mol per mol of platinum.