JPS6035373B2 - Room temperature curable silicone elastomer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a room-temperature curable silicone elastomer composition, particularly a one-component silicone elastomer composition with excellent adhesive properties, which cures at room temperature while releasing oxime in the presence of moisture. It is about things.

Various types of room-temperature-curing silicone elastomers are already known that are stable under closed conditions but cured by atmospheric moisture in the air, but dihydroxydiorganopolysiloxanes, oxime-substituted silanes, or The so-called oxime-free silicone elastomer composition, which is made of a partially hydrolyzed product and cures at room temperature by releasing oxime in the air, is used as a caulking material, a sealing material,
It is used in a wide range of fields as a coating material. However, the silicone rubber obtained from this composition has the disadvantage that although it adheres well to glass and ceramics, it has difficulty adhering to metals, plastics, painted surfaces, etc. depending on the surface condition. Therefore, when using this type of silicone elastomer composition, the treatment surface is usually pretreated with an appropriate primer, but this method depends on the individual There are disadvantages in that it is necessary to select a different primer and to change the application method.As a means to overcome these disadvantages, Y-aminopropyltriethoxysilane is added to this composition as an internal adhesion aid. A method of adding an alkyl-substituted alkoxysilane such as (see Japanese Patent Publication No. 46-11272), and a method of adding a silane having an oxime group and an alkoxy group (see Japanese Patent Publication No. 56-956) have been proposed. However, although these methods improve initial adhesion, they have the disadvantage that peeling phenomena are observed in deterioration tests, especially hot water deterioration tests.

The present invention relates to a composition of oxime-free silicone elastomer with improved adhesion that overcomes these disadvantages, and is composed of A) a general formula (wherein R1 and R2 are unsubstituted or substituted 1; Part by weight of dihydroxydiorganopolysiloxane 10 represented by a valent hydrocarbon group (m is an integer of 5 or more) Hydrogen group, X is =CR
2 or 5 groups, R4 is an unsubstituted or substituted monovalent hydrocarbon group, R5 is an unsubstituted or substituted divalent hydrocarbon group, a is 0 or 1) or an oxime-substituted silane or its partial hydrolyzate 0.5 to 3 parts by weight, C) General formula (where R6 and R7 are monovalent hydrocarbon groups, b is an integer of 0 to 2, n
is an integer of 0 to 4) 0.1 to 15 parts by weight of an organosilane or a partially hydrolyzed product thereof; D) a curing catalyst of 0 to 15 parts by weight;
and E) 0 to 30 parts by weight of filler.

To explain this, the present inventors have investigated various ways to improve the adhesion of oxime-free room-temperature curable silicone elastomer compositions. It was discovered that the adhesion to various adherends was improved when an aminosilane compound containing a penzyl group represented by the above general formula was blended, and it was also confirmed that this compound did not peel off even in a hot water deterioration test. The present invention has been completed.

A), B), D) and E) constituting the composition of the present invention
The component is a known room temperature curable silicone elastomer composition, which becomes a rubber elastic body through condensation of the hydroxyl group in component A) and the hydrolyzable group in component B). .

This dihydroxyorganopolysiloxane as component A) is represented by the general formula, and both ends are blocked with hydroxyl groups, and R1 and R2 in this formula are alkyl groups such as methyl group and ethylpropyl group, or cyclohexyl group. A cycloalkyl group such as a vinyl group, an alkenyl group such as an allyl group, a phenyl group, an aryl group such as a tolyl group, or a part of the hydrogen atom bonded to a carbon atom of these groups is replaced with a halogen atom, a cyano group, etc. substituted chloromethyl group,
3,3,3-trifluoropropyl group, y-cyanof.

A group selected from lopyl group, 8-cyanoethyl group, etc.
R1 and R2 may be the same group or different groups, and m in this formula represents 25q of organopolysiloxane.
Since the viscosity at C is preferably in the range of 25 to 500,00 ratio S, preferably 1,000 to 100,00 ratio S, it is an integer of 5 or more. Also, this B
) component, the oxime-substituted silane has the general formula Rbui(O
N=X)4-a, and this X is =CR
8 groups or groups, R3 and R4 are groups selected from the same group as R1 and R2, and R5 is a divalent hydrocarbon group such as a pentamethylene group or a divalent halogen-substituted hydrocarbon group such as a chlorobentamethylene group. The selected group may be one type, a mixture of two or more types, or a siloxane obtained by partially hydrolyzing these groups.

If the amount of oxime-substituted silane or its partial hydrolyzate is too small, crosslinking of the composition of the present invention will be insufficient, and if it is too large, the component form obtained by curing the composition will be too hard and brittle. Since the curing speed at room temperature becomes slow, it is preferable to mix the component in an amount of 0.5 to 3 parts by weight per 10 parts by weight of component A). Next, the oxime silane as component C) is added to A
), B) This improves the adhesion of the silicone rubber obtained from component B).
is a monovalent hydrocarbon group selected from an alkyl group such as a methyl group or an ethyl group, an alkenyl group such as a vinyl group or an allyl group, an aryl group such as a phenyl group or a tolyl group, and b is 0 to
2. n is an integer from 0 to 4, and this organosilane is (C & 0) 3SIC day 2C
QC6 days 4CH2NH2(CH30)8SIC days 2C
H2C6 ratio CH2NHCQC day 2 -N ratio, (C2
public ○) 3SIC days 2CQC 6 days 4C ratio 1 (NH
CQCH2)2NH2, (C2public○)3SIC
Day 2C ratio C6 Day 4C is (NHC ratio CH2)2NH2,C
(CH30) 2SIC day 2CH2C6 mountain CH2
- -NHC ratio CH2N ratio, (CH3)2(CH30
)SIC day 2CH2C6 day 4CH2NH2, (CH2
= CH) (CH30) 2 SIC days 2 CQC 6 days 4
-C string NHCH2C ratio NH2, etc., and these may be used alone or as a mixture of two or more, and siloxane obtained by partially hydrolyzing these may be used. good.

Among the above-mentioned compounds, the component C) is of the formula (CH
30) 3SIC days 2CQC 6 days 4CH2NH2--C ratio The organosilanes represented by NH2 are considered to be the most preferable in terms of their synthesis method and industrial raw material cost, but the amount of these organosilasos or siloxanes to be added should not exceed this. A) If the amount is less than 0.1 part by weight of component 10, the resulting silicone rubber will lack self-adhesive properties, and if it is more than 15 parts by weight, the curing reaction of the composition may be inhibited or the silicone rubber obtained may be impaired. Since the elasticity of the cured rubber deteriorates, the amount should range from 0.1 to 15 parts by weight, preferably from 0.5 to 5 parts by weight, based on 10 parts by weight of component A).

The curing catalyst as component D) constituting the composition of the present invention is used to accelerate the curing reaction of components A) and B) in the presence of moisture. Known ones may be used, and examples thereof include organic acid metal salts such as dibutyltin dilaurate, dibutyltin dioctoate, iron stearate, and octylic acid daily.

However, if a large amount of component D) is added, the storage stability of the silicone elastomer composition to which it is added will be impaired, and the cured product will be hard and brittle, so this addition amount is 4) The amount is preferably 10 parts by weight or less based on the weight of component 10, but it may not be added. The filler as component E) is added to impart suitable mechanical properties to the silicone rubber obtained by curing the composition of the present invention, and includes fumed silica, calcined silica, etc. Those known in the art such as silica, precipitated silica, fumed titanium oxide, carbon black, calcium carbonate, silica, calcium reninate, etc. are used, but these include various organosilanes and organosiloxanes. , or may be treated with hydrophobic treatment using hexamethyldisilazane or the like.

Although it is not necessary to add this filler, if it is added in too large a quantity, the fluidity of the silicone rubber will be poor and the cured silicone rubber will have a high modulus. ) The amount is preferably 30 parts by weight or less per 10 parts by weight of component. The composition of the present invention is made into a one-component room temperature curable silicone elastomer composition by uniformly mixing predetermined amounts of the above-mentioned components A) to E) in a dry atmosphere. Colorants, heat resistance or cold resistance improvers, to adjust
A thixotropy modifier, a dehydrating agent, a flame retardant agent, etc. may be added, and these may be added in predetermined amounts as necessary.

Next, Examples and Reference Examples of the present invention will be given, in which all parts are parts by weight, and viscosity is a value measured at 25:00.

Reference example [Aminoethyl (aminomethyl)] Synthesis of phenylethyltrimethoxysilane: 5 1915 g of ethylenediamine was charged into the separable flask and heated to 5000 ℃.
(Chloromethyl)phenylethyltrimethoxysilane 224 was added dropwise thereto over 2 hours while maintaining the temperature at 0 to 60°C. After the dropwise addition, the temperature was kept at 50 to 6000C for 2 hours to complete the reaction, and then allowed to cool.

Next, the upper layer and the lower layer were separated using a separating funnel, and 2801 g of the liquid obtained from the upper layer was distilled under reduced pressure to give a concentration of 170 to 1
181 fractions of 770/2 skin Hg were collected and IR
and analyzed by NMR, this is the formula (CH30)
3SIC day 2CH2C6 ratio CH2NH2-CH2CH2
It was confirmed that it was [aminoethyl (aminomethyl)] phenylethyltrimethoxysilane represented by NH2. Note that this yield was 76%. Example: 10 parts of dimethylpolysiloxane with a viscosity of 20.50 S, with both molecular chain ends blocked with hydroxyl groups, 1 part of hydrophobic atomized silica whose surface was silane-treated, and 0.2 parts of dibutyltin dioctate. After adding and mixing uniformly, add methyl tri(methyl ethyl ketoxime) to this in anhydrous state.
Composition 1 was prepared by mixing 7 parts of silane and 1 part of [aminoethyl] phenylethyltrimethoxysilane, which was specified in the reference example as a bonding aid, and performing defoaming treatment.
This adhesion aid is (aminomethyl)phenylethyldimethylmethoxysilane [(CH3)2(OC)SICQC
Composition 0 was prepared by blending in the same manner as above except that 1 part of 2C65CH2NQ was added, and as a comparative example, a composition in which this bush setting aid was not added at all (Comparative Example A), and a post-setting aid. Y-aminopropyltriethoxysilane [(C2day50)3S; CH2CH2CH2NH2]1
A composition (Comparative Example B) was made with the addition of 1.5%.

Next, the surface of each adhesive shown in Table 1 with a size of 25 cm x 10 cm x 1 to 5 ribs thick was cleaned in advance with ethanol,
1. Place these two pieces so that they overlap in the length direction. After arranging them in parallel with a distance of 100 mm, the above-mentioned compositions were filled into the gaps, and the temperature was 2000 and the relative humidity was 55%.
After being left for 7 days to harden in an atmosphere of Another sample piece obtained in the same manner was immersed in 5,000 ml of hot water for 7 days and its adhesion at seam breakage was measured in the same manner, and the results shown in Table 2 were obtained.

Table 1 Example 2 10 parts of dimethylpolysiloxane having a viscosity of 28.20 S with both ends of the molecular chain blocked by hydroxyl groups, 1 part of a hydrophobic atomized resin whose surface has been treated with silaso, and 15 parts of dibutyltin dilaurate. After uniformly mixing 0.3 parts, 7 parts of vinyltri(methylethylketoxime)silane and 1.5 parts of [aminoethyl(aminomethyl)]phenylethyltrimethoxysilane as an adhesion aid were added in an anhydrous state. Mixing and defoaming treatment to prepare composition m, and for comparison, N-(8-aminoethyl) was added in place of the above-mentioned adhesion aid.
-Y-Aminopropyltrimethoxysilane [(CH30
“3SIC day 2CH2C is NHCH2CH2NH2]1
．． A composition (Comparative Example C) was made by adding 5 parts.

Next, in accordance with JISA-5758, 5.12 rules, these compositions were filled onto an electrolytically colored aluminum plate, and this was left in an atmosphere of 2000, 55% RH for 14 days, and then for 3 days.
A Type 1 cured test piece was prepared by leaving it at 0qo for 14 days to harden, and this test piece was subjected to a tensile adhesion test at a rate of 5 ribs/min, and was immersed in hot water at 5,000 °C for 7 days, and then the same was done. When a tensile adhesion test was conducted, the results shown in Table 2 below were obtained.

Table 2 Example 3 10 parts of dimethylpolysiloxane with a viscosity of 49.80 ratio S, with both molecular chain ends blocked with hydroxyl groups, 5 parts of hydrophobic atomized silica whose surface was treated with silane, 8 parts of calcium carbonate, and [
(Aminoethyl) 2 parts of phenylethyltrimethoxysilane were mixed and defoamed to prepare Composition N.
A composition (Comparative Example D) was made by adding 2 parts of -aminoethyl)-Y-aminopropyltrimethoxysilane (supra).

Next, using these, JIS in the same manner as in Example 2.
Stainless steel (SUS304) according to A-5758
When a tensile adhesion test was conducted on the material, the results shown in Table 3 below were obtained.

Table 3

Claims (1)

[Claims] 1 A) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (Here, R^1 and R^2 are unsubstituted or substituted 1
dihydroxyorganopolysiloxane represented by a valent hydrocarbon group (m is an integer of 5 or more) 100 parts by weight B) General formula R_aSi(ON=X)_4_-_a
(Here, R^3 is an unsubstituted or substituted monovalent hydrocarbon group,
X is =CR_a group or ▲ has a mathematical formula, chemical formula, table, etc. ▼ group, R^4 is an unsubstituted or substituted monovalent hydrocarbon group, R^5 is an unsubstituted or substituted divalent hydrocarbon group, a is a 0 or 1)
Oxime-substituted silane or its partial hydrolyzate represented by 0.5 to 30 parts by weight C) General formula ▲ Numerical formulas, chemical formulas, tables, etc. b is an integer of 0 to 2, n is an integer of 0 to 4) Organosilane or its partial hydrolyzate 0.1 to 15 parts by weight D) Curing catalyst 0 to 10 parts by weight E) Filler 0 to 3
00 parts by weight of a room temperature curable silicone elastomer composition. 2 Organosilane as C component has the formula (CH_3O)_3SiCH_2CH_2C_6H_4
The room temperature curable silicone elastomer composition according to claim 1, which is an organosilane represented by CH_2NHCH_2CH_2NH_2.