JPH0391564A - Room temperature-curable organopolysiloxane composition - Google Patents

Abstract

PURPOSE:To prepare a room temp.-curable organopolysiloxane compsn. suitable as an insulating material around electric and electronic contact members and causing no contact fault by compounding a room temp.-curable organopolysiloxane compsn. contg. an organopolysiloxane as a main polymer with an org. compd. capable of forming a coordination compd. with a metal. CONSTITUTION:A room temp.-curable organopolysiloxane compsn. is prepd. by compounding: 100 pts.wt. organopolysiloxane (of which molecular terminals are OH groups or blocked by 2-3 alkoxy groups, vinyloxy groups, etc.) pref. having a viscosity at 25 deg.C of 25cst or higher; 100-400 pts.wt., pref. 5-200 pts.wt., filler; 0-50 pts.wt. alkoxysilane of formula I (wherein R<1> is an optionally substd. hydrocarbon group; R<2> is alkyl or alkoxyalkyl; and m is 0-2) or partially hydrolyzed product thereof; 0.01-10 pts.wt. guanidyl group-contg. organosilicon compd. of formula II (wherein R<3> is H or a monovalent hydrocarbon group); 0.01-10 pts.wt. organotin compd.; 0.1-20 pts.wt. organosilicon compd. of formula III; and 0.01-15 pts.wt. compd. capable of coordinating with a metal.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a room-temperature curable organopolysiloxane composition, which is particularly suitable as a material for use around electrical and electronic contact members, and which is free from causing contact failure. Regarding silicone compositions.

(Conventional technology) Heat-resistant,
Room temperature curable organopolysiloxanes are often used from the viewpoint of electrical properties and workability.

However, in room-temperature-curable organopolysiloxanes, volatile low-molecular-weight siloxanes are contained in organopolysiloxanes, which are the main polymers forming the composition, so the compositions can be used to store heat like contact parts. When used in a location where the low molecular weight siloxane is used, the low molecular weight siloxane will volatilize and burn due to the spark generated at the contact, forming silicon dioxide and adhering to the contact, making the contact part insulated and causing damage to motor circuits, relay circuits, etc. It has the disadvantage of causing contact failure, which prevents it from functioning properly.

Therefore, the present inventors have conducted various studies on silicone compositions that do not cause contact failure, especially when used as insulating materials around electrical and electronic contact members. We have surprisingly discovered that contact failure can be prevented by adding a small amount of an organic compound capable of forming a coordination compound with a metal to an organopolysiloxane composition, and have arrived at the present invention.

Accordingly, an object of the present invention is to provide a room temperature curable silicone composition which is suitable as an insulating material around electrical/electronic contact members and which does not cause contact failure.

(Means for Solving the Problems) The above object of the present invention is to provide (A) a diorganopolysiloxane whose molecular chain terminals are blocked with a hydroxyl group, two or three alkoxy groups, or a vinyloxy group;
100 parts by weight, (B) filler: 1-
400 parts by weight, (C) alkoxysilane represented by the general formula % formula % (1) or a partial hydrolyzate thereof:
0 to 50 parts by weight, (D) an organosilicon compound having at least one group represented by the general formula % in one molecule: 0.01 to 10 parts by weight, (E) an organotin compound: 0. 01 to 10 parts by weight, (F) Organosilicon compound having a group represented by the general formula: 0.1 to 20
Part by weight, and (G) organic compound capable of coordinating with metal: 0.0
This was achieved with a room temperature curable organopolysiloxane composition containing 1 to 15 parts by weight.

The reason why contact failure can be prevented by adding a trace amount of an organic compound capable of forming a coordination compound with a metal to the silicone composition is considered to be as follows.

In general, low-molecular-weight siloxane is burned by sparks generated at electrical contacts, and the silica produced forms an insulating film, which can cause the contacts to fail and cause the motor to rotate or stop.
The relay will malfunction, but if there is an organic compound with coordination ability on the metal, the organic compound will preferentially adsorb and coordinate on the fresh metal surface of the contact area, and then the silica that is generated will adsorb and adhere. This is thought to be to prevent this.

The diorganopolysiloxane (A) 1 component constituting the composition of the present invention is the main ingredient of the present m* product, and is, for example, an average composition formula: % formula % (where R is independently substituted or an unsubstituted monovalent hydrocarbon group, a is a number from 1.90 to 2.05), and the molecular chain terminal is a hydroxyl group, 2 to 3 alkoxy groups, or a vinyloxy group. There are things that are closed. Examples of R include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, 2-ethylbutyl group, and octyl group, cycloalkyl groups such as cyclohexyl group and cyclopentyl group, and alkenyl groups such as vinyl group and hexenyl group. , aralkyl groups such as phenyl, tolyl, xylyl, naphthyl, and diphenyl groups, or chloromethyl in which some or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with halogen atoms, cyano groups, etc. There are substituted hydrocarbon groups such as trifluoropropyl group, 2-cyanoethyl group, and 3-cyanopropyl group.

In order to impart good rubber elasticity and mechanical strength to the cured product obtained from the &[l parabolite of the present invention, the viscosity of the component (A) at 25° C. is preferably 25 cSL or more.

Further, the filler as component (B) in the composition of the present invention may be a known filler, such as finely powdered silica, silica aerogel, precipitated silica, diatomaceous earth, metals such as iron oxide, zinc oxide, titanium oxide, etc. oxides or their surfaces treated with silane, calcium carbonate, magnesium carbonate,
Metal carbonates such as zinc carbonate, asbestos, glass wool,
There are synthetic resin powders such as carbon black, fine mica powder, fused silica powder, polystyrene, polyvinyl chloride, and polypropylene. The blending amount of this component (B) is as described above (
A)* It is in the range of 1 to 400 parts by weight, preferably in the range of 5 to 200 parts by weight, per 100 parts by weight. If it is less than 1 part by weight, the cured product obtained from the Kigumi acid will not exhibit sufficient mechanical strength, and if it exceeds 400 parts by weight, the viscosity of the composition will increase and the workability will not only deteriorate. , the rubber strength after curing decreases, making it difficult to obtain the desired rubber elastic body.

The alkoxysilane as component (C) used in the present invention is represented by the general formula % (1), in which R1 is a substituted or unsubstituted monovalent hydrocarbon group, such as a methyl group, Examples include ethyl group, propyl group, vinyl group, phenyl group, and trifluoropropyl group. R mushroom is an alkyl group or an alkoxyalkyl group, and examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, and alkoxyalkyl groups such as methoxyethyl group and ethoxyethyl group. m is 0. It is an integer between ~2.

Examples of the alkoxysilane of component (C) include methyltrimethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, methyltriisopropoxysilane, phenyltrimethoxysilane, Phenyltri(methoxyethoxy)silane, vinyltri(methoxyethoxy)silane, tetra(ethoxyethoxy)silane, trifluoropropyltrimethoxysilane, etc. can be used, as well as partial hydrolysates of these, that is, partial hydrolysis condensation. It is also possible to use siloxanes.

Among the above compounds, especially methyltrimethoxysilane,
Vinyltrimethoxysilane, phenyltrimethoxysilane, tetratrimethoxysilane, methyltri(methoxyethoxy)silane, vinyltri(methoxyethoxy)silane and the like are preferred.

The blending amount of component (C) is in the range of 0 to 50 parts by weight, preferably 0 to 10 parts by weight, per 100 parts by weight of component (A). If the amount of component (C) is more than 50 parts by weight, the resulting cured product will have poor rubber elasticity and will be economically disadvantageous.

The organosilicon compound as component (D) used in the present invention is a compound having at least one group represented by the general formula % () in one molecule, and is It acts as a catalyst when silylating water and silanol groups.

Incidentally, R3 is a hydrogen atom or a monovalent hydrocarbon group similar to R1 in the component (C).

The group of the above general formula (II) is bonded to a silicon atom via a bonding group, and the bonding group is generally preferably an alkylene group or an oxyalkylene group.

As a specific example of the above (D) JjR portion, for example, / (CHs) J / (CHs) xN / (CHs) J CH3 / (CHs)xN Examples include organosilicon compounds represented by:

this Among them, Since the base is easy, the formula: %formula%) Organosilanes represented by are preferred.

The blending amount for 1 minute (D) is in the range of 0.0f-10 parts by weight, preferably 0.1 to 5 parts by weight, per 10 parts by weight of component (A). If the (D) tc content is less than 0.01 part by weight, the effect of promoting the reaction between the base compound consisting of components (A) and (B) and component (C) will be insufficient, and the above reaction will not occur. In addition to requiring a long time, hydroxyl groups and water remain in the reaction product, resulting in poor storage stability of the m-acid. Moreover, if the amount of component (D) is more than 10 parts by weight, there is a risk that the reaction product will change color, and it is also economically disadvantageous.

The organic tin compound used as component (E) in the present invention is a known condensation reaction catalyst that has been conventionally used in this type of composition, such as tin naphthenate, tin caprylate, tin oleate, etc. carboxylic acid salts such as dibutyltin diacetate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin diralate, diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis(triethoxysiloxy)tin, dibutyltin diacetate, Benzyl malate and the like can be used. The amount of component (E) to be blended is 0.01 to 10 parts by weight, preferably 0.1 to 2 parts by weight, per 100 parts by weight of component (A). If the amount of (E)* is less than 0.01 part by weight, the function as a curing catalyst will not be fully exhibited, resulting in a long curing time and insufficient curing in the deep part of the upper rubber layer. Further, if the amount is more than 10 parts by weight, the storage stability of the composition will be lowered.

The organosilicon compounds used as (F)* are the above-mentioned (A) 1-minute diorganopolysiloxane and (B)
The alcohol generated by the reaction between the silanol groups and water contained in the component filler and the (C) tc alkoxysilane or its partial hydrolyzate reacts as shown in the reaction formula below to produce alcohol. It is to be removed.

(Here, R4 is a substituted or unsubstituted monovalent hydrocarbon group similar to R1 described above, Rs and R6 are hydrogen atoms, methyl groups, or ethyl groups, n is 0.1 or 2, and R
is an alkyl group. ) The alkoxysilane or alkoxysiloxane and ester compound produced in the above reaction do not have any adverse effect on the composition of the present invention. Therefore, the addition of the organosilicon compound as component (F) improves the storage stability of the composition of the present invention. It will be excellent.

Since the reaction between the organosilicon compound of the component (F) and the alcohol proceeds easily and stoichiometrically, the amount of the component (F) to be blended should be such that the molar ratio of the component (F) is the same. Therefore, the blending amount is generally 0.1 parts by weight or more, preferably 10 parts by weight per 100 parts by weight of (A).
Parts by weight or less. (A) 0.00 parts per 100 parts by weight of labor.
If the amount is less than 1 part by weight, alcohol may remain.

Further, it is usually not necessary to mix more than 10 parts by weight, which is economically disadvantageous.

Here, the component (F) has a group represented by the general formula (II[) in its structure, and at the same time, St.
(OR')j! (Here, R is the same alkyl group or alkoxyalkyl group as R, and l is 2 or 3.) In the case of a silicon compound having an alkoxysilyl group, it can be used as a curing agent as described above. <c>
Addition of tc is optional.

The (F) component is (CH3) 5sicH*cOOcHs・, (C1ls
) ssicHxcOOcglls(CHs) 5si
cHzcOo(n)CsL(C113) ssicHg
cOo(n)CJ*The following are exemplified.

(CHs) ssicHmcOo (n) CsH+t (CJs) 5slcHxcOOcJslh (zHsSiCIIzCOOClHs aS CHs (Cslls) gsicHmcOOcHa, ((n)
CsHy) 5sicH*cOOcJs((n)CsH
l) ssicflgcOOcHz, ((rl)Csl
ly)ssicHtcOo(n)Cant((n)Cs
llt) 5sicHtcOo(n) Cant tUS C old CH! (n) CsH+y CH3 SiCHgC00Ctlls CHl (n) C1111g (CH3) 5sicllxcHxcOOctHs(C
Js) ssicHzcHzcOOcHs(CtlsO
) ssicHgcOOc, Hs -CH11 (CB10) msicIIgcOOcxRs (CHs
O) sslcHmcOo(n)C411s , (CH
sO) sslcII*cOO(n)CJ+? , (C.J.s.
O) 5SICHxCOOCtHi1(C4H90)
sSiCIbCOOCtHs-(CJsO) 5sic
HxcOo(n)CaH*(CJsO)ssicHzc
OO(n)Cwll+t, n is 0 or a positive integer n is 0 or a positive integer n is O or a positive integer (C1ls) gslcHmcOOcl玽.

(CIIs) gsicRgcOOcJs (F) component may be a partially hydrolyzed product of the above compound, that is, a partially hydrolyzed condensed siloxane.

Component (G) used in the present invention has a boiling point of 5 at normal pressure.
Although there are no particular limitations as long as the organic compound is 0 to 300°C, it is preferable to use one that adsorbs and coordinates to metals but does not show corrosive properties.Specific examples of such organic compounds include anisole, , ethers such as diglyme, β-ketoesters such as ethyl acetoacetate and methyl acetoacetate, diketones such as acetylacetone, phosphines such as triethylphosphine and triphenylphosphine, phosphites such as trimethylphosphite and tributylphosphite. phosphates such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate, organic phosphorus compounds, olefins such as styrene, l-octene, cyclohexane, acetylene compounds such as diphenyl sulfide, phenylbenzyl sulfide, etc. Examples include sulfides, sulfoxides such as dimethyl sulfoxide, lactones, and lactams.

The amount of organic compound capable of coordinating with metal is 100% organopolysiloxane! 0°01~15 for i quantity part
Parts by weight, preferably 0.1 to 5 parts by weight. Addition amount is 0. If it is less than 1 liter part of O, there is no effect, and if it is more than 15 parts by weight, the physical properties of the silicone composition will deteriorate.

The I acid compound of the present invention can be obtained by mixing the components (A) to (G) described above. In this production, the above-mentioned components (A) to (G) may be mixed at once, or (A
) to (E) components may be mixed together under reduced pressure in a sealed container, and then the organosilicon compounds of components (F) and (G) may be added and mixed. In this case, the mixing temperature is preferably between room temperature and 100°C. .

Furthermore, the composition of the present invention may contain, if necessary, a thixotropy-imparting agent such as polyethylene glycol and its derivatives, a pigment, a dye, an anti-aging agent, an antioxidant, an antistatic agent, antimony oxide, chlorinated paraffin, etc. So-called carbon functional silane having thermal conductivity improvers, adhesion imparting agents, amino groups, epoxy groups, thiol groups, etc.
Various conventionally known additives such as metal salts of carboxylic acids and metal alcoholades can be blended.

(Effects of the Invention) The composition of the present invention does not cause electrical contact failure, so it is suitable for applications such as adhesives, coatings, and potting materials for electrical and electronic parts. The invention will be described in further detail, but the invention is not limited thereby.

Example 1 Low molecular weight siloxane content is 0.2% and viscosity is 5°000
To 88 parts of dimethylpolysiloxane, which is cSt and whose molecular chain ends are capped with hydroxyl groups, 9 parts of fumed silica whose surface has been treated with trimethylsilyl groups and 3 parts of fumed silica whose surface has been treated with cyclic dimethylpolysiloxane are added. ,
A base combiner was manufactured by uniformly mixing the mixture.

Next, 5 parts of vinyltrimethoxysilane, 065 parts of T-tetramethylguanidylprobyltrimethoxysilane, 10.2 parts of diptyltin dimethoxy and 2 parts of ethyltrimethylsilyl acetate were added to 100 parts of this base compound, and the mixture was heated to 60 parts under reduced pressure. After mixing for a minute, 1.0 part of ethyl acetoacetate was added. The mixture was stirred for 10 minutes with exclusion of moisture and under reduced pressure to form a room temperature curable organopolysiloxane.

In addition, the said low molecular weight siloxane is a cyclic dimethyl polysiloxane represented by the general formula, and n is 3-20.

Next, 100g of the obtained cured product was added to a volume of 5j! into a variable constant voltage power supply (2°OV-150) shown in Figure 1.
A mounting test (3 pieces) of micro motors (M) using mA) was conducted, and the waveform of this motor was observed using a synchroscope. Assuming that contact failure occurred when the waveform became abnormal, these compositions were investigated for the occurrence of contact failure, and the results shown in Table 1 were obtained.

Example 2 A room-temperature curable organopolysiloxane was prepared in exactly the same manner as in Example 1, except that phenylacetylene was used instead of ethyl acetoacetate as the substance (G) capable of coordinating to metals. The obtained organopolysiloxane was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 A room-temperature-curable organopolysiloxane was prepared in exactly the same manner as in Example 1, except that triethyl phosphate was used instead of ethyl acetoacetate as the substance (G) capable of coordinating to metals. The obtained organopolysiloxane was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 Low molecular weight siloxane content is 0.2% and viscosity is 5°000
88 parts of dimethylpolysiloxane which is cSt and whose molecular terminals are capped with trimethoxysilyl groups, 9 parts of fumed silica whose surface has been treated with trimethylsilyl groups, and 3 parts of fumed silica whose surface has been treated with cyclic dimethylpolysiloxane. was added and mixed uniformly to produce a base compound.

Next, to 100 parts of this base compound, 0.5 part of T-tetramethylguanidylpropylmethoxysilane, 0.2 part of dimethyltin malate, and 3 parts of 1-) liftoxysilyl-2-carboethoxymethyldimethyl ether were added. After stirring for 60 minutes under reduced pressure, 1.0 parts of triethyl phosphate was added. The above mixture was stirred for 10 minutes under reduced pressure with exclusion of moisture to obtain a room temperature curable organopolysiloxane. The obtained organopolysiloxane was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1゜Example 1 except that the substance capable of coordinating with metal CG) was not used.
A room-temperature curable organopolysiloxane was prepared in exactly the same manner as in Example 1, and the results were evaluated in the same manner as in Example 1, as shown in Table 1.

The results of the Examples and Comparative Examples shown in Table 1 and above demonstrate that the silicone composition of the present invention is extremely unlikely to cause contact failure.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the implementation of a micromotor using a variable constant voltage power supply.M in FIG. 1 represents a micromotor.

Claims (1)

[Scope of Claims] (A) Diorganopolysiloxane whose molecular chain terminals are blocked with hydroxyl groups, 2 to 3 alkoxy groups, or vinyloxy groups: 100 parts by weight, (B) Filler: 1 to 40 parts by weight
0 parts by weight, (C) General formula (R^1)_mSi(OR^2)_4_-_m...(
I) (where R^1 is a substituted or unsubstituted monovalent hydrocarbon group, R^2 is an alkyl group or an alkoxyalkyl group, and m is an integer of 0 to 2); Partial hydrolyzate thereof: 0 to 50 parts by weight, (D) General formula [(R^3)_2N]_2C=N-...(II) (where R^3 is a hydrogen atom or a monovalent hydrocarbon Organosilicon compound having at least one group represented by ) in one molecule: 0.01 to 10 parts by weight, (E) Organotin compound: 0.01 to 10 parts by weight, (F) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc.▼...(III) (Here, R^4 is a substituted or unsubstituted monovalent hydrocarbon group, and R^5 and R^6 are hydrogen atoms, methyl groups, or ethyl groups. and n is 0, 1 or 2): 0.1 to 20 parts by weight; and (G) an organic compound capable of coordinating with a metal: 0.0
A room temperature curable organopolysiloxane composition comprising 1 to 15 parts by weight.