JPS6243460A - Room temperature curable silicone composition improved in adhesiveness - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to iR curable silicone rubber compositions that, when cured, exhibit excellent adhesion. For more details,
The present invention provides a curable silicone rubber composition comprising a polydiorganosiloxane in which the silicon atom at the end of each polymer chain is terminated with at least two hydrolyzable groups, a nonchelating condensation catalyst, and a metal chelate adhesion promoter. relating to things.

BACKGROUND OF THE INVENTION Prior to the present invention, it is well known in the art that various carboxylic acid metal salts, metal chelates, organic acids, and organic bases can be used as condensation catalysts for room temperature curable silicone rubber compositions.

Evans U.S. Patent No. 3,622,52
No. 9 discloses a composition that is stable under substantially anhydrous conditions but capable of curing to an elastic solid state in the presence of moisture, the composition comprising a silanol chain-terminated polydiorganosiloxane of the formula % Formula %) [In the formula, R and R2 are each an organic group having 18 or less carbon atoms selected from hydrocarbyl, halohydrocarbyl, nitrohydrocarbyl, and alkoxyhydrocarbyl, and R1 is hydrogen or selected from hydrocarbyl, halohydrocarbyl, and cyanoalkyl. R3 is hydrogen or an organic group having 18 or less carbon atoms selected from hydrocarbyl, halohydrocarbyl, nitrohydrocarbyl, alkoxyhydrocarbyl, dialkylamino and R'QC-CH,-, and R4
is aliphatic hydrocarbyl, aliphatic halohydrocarbyl,
an organic group selected from aliphatic nitrohydrocarbyl and R5 and R6 are each aliphatic hydrocarbyl, a is an integer of 2-4, b is an integer of 0-2,
d is O or 1 and the sum of a, b, and d is 4], and optionally small amounts of carboxylates and/or chelates of metals in the electrochemical series of metals from lead to manganese. Includes evening.

Smith et al. US Patent M3. 708.
No. 467, compositions that are stable under substantially anhydrous conditions but capable of curing to an elastic solid state are silanol chain-terminated polydiorganosiloxanes, formula R, SL (
OR' ) [wherein R and R1 are a group having about 8 or less carbon atoms selected from the group consisting of human 1 drocarbyl, halohydrocarbyl and cyano lower alkyl], and lead in the electrochemical series of metals. A catalyst system comprising a first catalyst that is a salt, alkoxide, hydroxide or oxide of a metal ranging from manganese to manganese and a second catalyst that is a titanium chelate.

The present invention provides improved adhesion when a polydiorganosiloxane in which the silicon atom at the end of each polymer chain is terminated with at least two hydrolyzable groups is used in combination with a nonchelating condensation catalyst and a metal chelate adhesion promoter. This was based on this surprising finding.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a room temperature curable silicone rubber composition that exhibits excellent adhesion to a variety of substrates when cured.

Another object of the present invention is to provide a method for producing room temperature curable silicone rubber compositions which, when cured, exhibit excellent adhesion to a variety of substrates.

According to a first aspect of the invention, (a) a polydiorganosiloxane having a low number of silicon atoms at the end of each polymer chain (both terminated with two hydrolyzable groups); (b) an effective amount of a non-chelating condensation catalyst; and (c) a room temperature curable silicone rubber composition is provided that exhibits excellent adhesion upon curing, comprising an effective amount of a metal chelate adhesion promoter.

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that it cures to an elastic solid state when exposed to moisture;
Room temperature curable silicone rubber compositions exhibiting improved adhesion to a variety of substrates include (a) a polydiorganosiloxane in which the silicon atom at the end of each polymer chain is terminated with at least two hydrolyzable groups; b) an effective amount of a nonchelating condensation catalyst; and (c) an effective amount of a metal chelate adhesion promoter.

Polydiorganosiloxanes in which the silicon atom at the end of each polymer chain is terminated with at least two hydrolyzable groups are already known in the art. Such polydiorganosiloxanes can be represented by the following formula.

where R is a monovalent substituted or unsubstituted C(1-13) hydrocarbon group, preferably methyl, some 0 (larger amounts of methyl and smaller amounts of phenyl, cyanoethyl, trifluoropropyl, vinyl or a mixture thereof, R1 is a C aliphatic organic group or C aralkyl group selected from the group consisting of alkyl, alkyl ether, alkyl ester, alkyl ketone and alkyl cyano group, and R2 is a monovalent Substituted or unsubstituted C
(1-13) is a hydrocarbon group; in,
b is 0-2, the sum of a+b is equal to 0-3, and n is about 2
It is an integer up to 500. Preferably R1 and R2 are methyl.

Polydiorganosiloxanes within formula (1) above are known in the art and are described, for example, in commonly assigned U.S. Pat. No. 4,395,526 to White et al.

It is particularly preferred that at least two alkoxy groups are bonded to the silicon atom at each polymer chain end of the polydiorganosiloxane (a). These polyalkoxy-terminated polydiorganosiloxanes include, for example, Chung
No. 4,515,932.

The condensation catalyst (b) used in the practice of the present invention may be any condensation catalyst known in the art other than Metal Kill-1. The reason for excluding metal chelates is that in the present invention, metal chelates, which are commonly used as condensation catalysts, are used as adhesion promoters. Therefore, those skilled in the art will appreciate that although metal chelates primarily function as condensation catalysts, in the present invention metal chelates are used primarily as a means to improve the adhesion of cured linicone compositions to various substrates. It should be done.

Therefore, for the purposes of the present invention, condensation catalysts can be selected from, for example, metal salts of monocarboxylic and dicarboxylic acids, metal alkoxides, organic bases, organic acids, and the like.

Preferably, the condensation catalyst is a metal salt of a carboxylic acid, in particular a tin compound, such as dibutyltin dilaurate, schif'tyltin acetate, nbutyltin simetoquine, carbomethquine phenyltin trisuberate, tin octoate, dimethyl Particularly preferred are tin dibutyrate, triethyltin tartrate, tin oleate and tin naphthenate. Dibutyltin diacetate is particularly preferred.

Examples of other metal condensation catalysts include zirconium octoate,
Lead 2-ethyl octanoate, iron 2-ethylhexanoate, 2
Cobalt ethylhexanoate, manganese 2-ethylhexanoate, zinc 2-ethylhexanoate, antimony octoate, bismuth naphthenate, zinc naphthenate and zinc stearate.

Examples of non-metallic condensation catalysts include hexylammonium acetate and benzyltrimethylammonium acetate.

Other suitable condensation catalysts will be apparent to those skilled in the art or can be readily ascertained without undue experimentation.

- Advantageously, the q-movement of the condensation catalyst is about 0.001 to about 2 parts by weight per 100 parts by weight of polydiorganosiloxane (a). Polydiorganosiloxane (a) 1 as a condensation catalyst
00! Approximately 0.0 per part IiQ. A range of 1 to about 1 part by weight is preferred.

The metal chelates used as adhesion promoter (c) in the practice of the present invention include lead, tin, zirconium, antimony,
41 - Cleans based on lead, chromium, cobalt, nickel, aluminium, gallium, germanium or titanium
It is possible to make it 1. However, titanium chelate is more preferred as the metal chelate.

Specific examples of titanium chelate compounds useful in the practice of this invention include Weycnbcrg U.S. Pat. No. 3,334.067, Smith (Sm 1t1
1) et al., U.S. Pat. No. 3,689,454 and Beers et al., U.S. Pat. No. 4,438,039.

Examples of preferred titanium chelates include the following.

The following compounds are also preferred.

Diisostearoyl ethylene titanate, titanium dimethacrylate oxyacetate-1, titanium diacrylate oxyacetate, titanium di(cumylferrate) oxyacetate, titanium di(dioctyl phosphate) oxyacetate, titanium di(dioctyl phosphate) ethylene titanate , titanium (dioctyl pyrophosphate) oxyacetate, di(dioctyl pyrophosphate) ethylene titanate.

The titanates listed below are particularly suitable.

It has been determined that an effective amount of metal chelate welding promoter generally ranges from about 0.05 to about 2 weight percent of the polydiorganosiloxane (a). Of course, larger quantities can be used, but no particular advantage is obtained. When metal chelate usage is below about 0.05% by weight, the strength of the adhesive bond between the silicone elastomer and the substrate is not sufficient for most purposes. In a preferred embodiment, the metal chelate is about 0.1-
Approximately 1.5 cubes of melon should be present. Of course, mixtures of metal chelates are also contemplated by the present invention.

The compositions of the invention may also contain conventional additives such as fillers, plasticizers, crosslinkers, scavengers of hydroxyl functions, and the like.

In the practice of the present invention, the room temperature curable composition can be prepared by stirring, e.g. stirring, the components of the curable composition under conditions substantially free of moisture.

The temperature can vary from about 0° C. to about 1808° C. depending on the degree of compounding, type and amount of filler, etc.

In a preferred method of making the compositions of the present invention, a polydiorganosiloxane having at least two hydrolyzable groups at each polymer chain end is mixed with a reinforcing filler and a plasticizing fluid to form an RTV base formulation. Create. after that,
Silane crosslinker, scavenger for hydroxy functional groups,
Mix the condensation catalyst and metal chelate adhesion promoter with the RTV base formulation.

The following examples are presented by way of illustration, and not as limitations, to enable those skilled in the art to practice the invention. All parts are claw parts unless otherwise specified.

EXAMPLES Example 1 A vinyl dimethoxy terminated polydimethylsiloxane was prepared. That is, a 1 gallon Ross mixer equipped with a vacuum line and nitrogen purge line was heated at 22°C at 25°C.
．． 100 parts by weight of silanol-terminated polydimethylsiloxane having a 0.000 centipoise tie, 1.5 parts by weight of vinyltrimethoxysilane, 0.2 parts by weight of dibutylamine, and 0.05 parts by weight of acetic acid were charged. The mixture was stirred for 15 minutes at 100'C under nitrogen atmosphere. 5
l for a further 45 min at 100 °C under vacuum of mIII g.
Combination yielded a storage-stable vinyl dimethine-terminated polydimethyloloxane having a viscosity of 26.900 centipoise at 25°C.

Example 2 One Gallon Baker-Perkins Installed with Vacuum Line and Nitrogen Purge Line
In a mixer, add 100 parts of vinyldimethoxy-terminated polydimethylammonoxane subjected to AJS in Example 1, 40 parts of fuyumdonica filler treated with octamethylcyclotetranoxane and hexamethylammonoxane, and 2 parts of 300
A charge of 40 parts by weight of 0 centipoise t-butylene lanol-terminated polydimethylsiloxane and 15 parts by weight of 50 centipoise silanol-terminated polydimethylsiloxane was charged. This mixture was stirred under vacuum for 60 minutes to form the RTV base formulation.

Using a SOOICO [F] catalyst addition and mixer, add 100 parts of RTV base formulation to 7 parts of vinyltrimethquine crosslinker and 2 parts of hydroxy functional hexamethyldisilazane scavenger. Part, dipropoxy titanium bis-(ethyl acetoacetate)
1.0 parts by weight and 0.1 parts by weight of dibutyltin diacetate were added. After mixing, a series of physical properties of the composition were measured.

The results are shown in Table 1.

Specific gravity 1.085 Application speed (g/min) 24° Stick-free time (min) 30 Flow (inch) 0.05 Numerometer hardness (Shore A) *33 33 Tensile (1) s i ) *519 Elongation (96 )
*491 jll! ;I contact 6 (ppi)” Aluminum 2024 80 Cold rolled steel plate 55 Glass
83 Accelerated for 148 hours at 100°C** Nurometer hardness (Shore A) 35 Tensile strength (psi) 409 Elongation (%) 461 * Cured for 70 hours at RH50% and 259C HRH5Q%
Example 3 Example 1 was repeated using 1.5 ffiQ parts of methyltrimethoxysilane to yield a methyldimethoxy-terminated polydimethylsiloxane having a viscosity of 26,500 centipoise at 25°C.

Example 4 An RTV base formulation was made as in Example 2 using the methyldimethoxy-terminated polydimethylsiloxane of Example 3, and the vinyltrimethoxysilane crosslinking agent was replaced with 1 part of the methyltrimethoxysilane crosslinking agent. Replaced. The physical properties of this composition were also measured.

The results are shown in Table 2.

Specific gravity 1.08G Application speed (g/min) 224 Stick-free time (min) 30 Flow (inch) 0.05 Durometer hardness (Shore A) *35 35 Tensile (psi) *49g Elongation (%) '550 Peel contact j ': (ppi)'' Aluminum 2024 74 Cold rolled steel plate 68 Glass
82 Accelerated aging at 100°C for 548 hours Durometer hardness (Shore A) 31 Tensile strength (
psi) 3B2 elongation (%)
491 * RH50%, cured for 7 days at 25°C HRH5Q? 6
．． Cured for 140 hours at 25°C Example 5 In this example, Example 4 was repeated without the addition of titanium chelate. The results are shown in Table 3.

Hi! 1.083 Application speed (57 minutes) 201 Tack-free time (minutes) 30 Flow (inches) 005 Nurometer hardness (Shore A)” 31 Tensile strength (psi) *435 Elongation (%) *502 Peel adhesion (ppi) ” Aluminum 2024 0 Cold rolled steel Saka O Glass 0 100°C 148 hours accelerated aging *1 Durometer hardness (Shore A) 30 Tensile strength (psi) 401 Elongation (96) 398*RH50%,
Cured for 7 days at 25°C** RH5006, cured for 14 days at 25°C Example 6 Example 4 was repeated again but this time with 1. 0ffiff 1 part of aminoethylaminopropyl trimethochine silane was used as an adhesion promoter. The results are shown in Table 4.

Disaster relief Experimental result characteristics of Example 6 Conclusion of Song Dynasty in Example 6
1.080 Yufu speed (g
/min) 281 Stick-free time (min) 20 Flow (inch) 0.05 durometer hardness (Shore A) *41 41 Tensile (psi) *472 Elongation (%) *410 Stripped female joint pipe (ppj)" Aluminum 2024 12 cold rolled steel plate 4 glass
14 Accelerated aging at 1-00°C for 148 hours *1 Durometer hardness (Shore A) 38 Draw length strength (psi) 4
02 Elongation (%) 451 *Cured at RH5096, 25°C for 70 hours* Cured at RH50%, 25°C for 140 hours Example 7 Example 4 was repeated, but the synthetic leather was 1. OffJm part 1.
3-Dioxypropanethane-bis(acetylacetonate) was used as an adhesion promoter. The test results are shown in Table 5.

Table 5 Experimental result characteristics of Example 7 Result specific gravity of Example 7
1.089 application speed (7 minutes) 201 Tack-free time (min) 30 Flow (inch) 0.05 Durometer hardness (Shore A)' 42 Tensile strength (psD*520 Elongation (%, *641 Peeling I4
1 stone (ppi)” Aluminum 2024 71 cold rolled j
T41 & 58 glass
86 Accelerated aging at 100°C for 148 hours/Urometer hardness (Shore A) 34 Tensile strength (psi) 441 Elongation (%) 519

Claims (1)

[Scope of Claims] 1. (a) a polydiorganosiloxane in which the silicon atom at the end of each polymer chain is terminated with at least two hydrolyzable groups; (b) an effective amount of a non-chelating condensation catalyst; and (c) an effective amount of a non-chelating condensation catalyst. A curable composition comprising an amount of a metal chelate adhesion promoter. 2. Polydiorganosiloxane has the general formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R in the formula is a monovalent substituted or unsubstituted C_(_1
_-_1_3_) hydrocarbon group, R^1 is C(1-
8) an aliphatic organic group or a C_(_7_-_1_3_) aralkyl group,
R^2 is a monovalent substituted or unsubstituted C_(_1_−_1_
3_) A hydrocarbon group, where X is a hydrolyzable group selected from the group consisting of amide, amino, carbamato, enoxy, imidato, isocyanato, oximato, thioisocyanato and ureido groups, a is 0 or 1, and b is 0 2. The composition of claim 1, wherein the sum of a+b is equal to 0-3, and n is an integer up to about 2,500. 3. A patent claim in which R is methyl or a mixture of a large amount of methyl and a small amount of phenyl, cyanoethyl, trifluoropropyl, vinyl or a mixture thereof, R^1 is methyl and R^2 is methyl The composition according to item 2. 4. The composition according to claim 3, wherein at least two methoxy groups are bonded to the silicon atom at the end of each polymer chain of the polydiorganosiloxane. 5. The composition according to claim 1 or 2, wherein the condensation catalyst is a metal salt of a monocarboxylic acid, a metal salt of a dicarboxylic acid, a metal alkoxide, an organic base, an organic acid, or a mixture thereof. 6. The composition according to claim 5, wherein the condensation catalyst is a metal salt of a monocarboxylic acid, a metal salt of a dicarboxylic acid, a metal alkoxide, or a mixture thereof. 7. The composition according to claim 6, wherein the metal is tin. 8. The composition of claim 5, wherein the condensation catalyst is present in an amount of about 0.001 to about 2 parts by weight per 100 parts by weight of polydiorganosiloxane. 9. Metal chelates include lead, tin, zirconium, antimony, zinc, chromium, cobalt, nickel, aluminum,
Composition according to claim 1 or 2, based on a metal selected from the group consisting of gallium, germanium and titanium. 10. The composition according to claim 9, wherein the metal chelate is a titanium chelate. 11. The composition according to claim 5, wherein the metal chelate is a titanium chelate. 12. Titanium chelate is polydiorganosiloxane 10
11. The composition of claim 10, wherein the composition is present in an amount of about 0.05 to about 2 parts by weight per 0 parts by weight. 13. Titanium chelate is polydiorganosiloxane 10
12. The composition of claim 11, wherein the composition is present in an amount of about 0.05 to about 2 parts by weight per 0 parts by weight. 14. The cured composition according to claim 1. 15. The cured composition according to claim 2. 16. (a) each polymer chain has at least two silicon atoms at the end;
Curing comprising mixing under substantially anhydrous conditions a polydiorganosiloxane terminated with two hydrolyzable groups, (b) an effective amount of a nonchelating condensation catalyst, and (c) an effective amount of a metal chelating adhesion promoter. Method for producing a sexual composition. 17. Polydiorganosiloxane has the general formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R in the formula is a monovalent substituted or unsubstituted C_(_1
_-_1_3_) hydrocarbon group, R^1 is C_(_
1_-_8_) aliphatic organic group or C_(_7_-_1
_3_) aralkyl group, R^2 is a monovalent substituted or unsubstituted C_(_1_-_1_3_) hydrocarbon group, and X is an amide, amino, carbamato, enoxy, imidato, isocyanato, oximato, thioisocyanato and ureido group; a is 0 or 1, b is 0-2, the sum of a+b is equal to 0-3, and n is an integer up to about 2,500; The method according to item 16. 18. The method according to claim 17, wherein at least two alkoxy groups are bonded to the silicon atom at each polymer chain end of the polydiorganosiloxane. 19. The method according to claim 17, wherein the condensation catalyst is a metal salt of a monocarboxylic acid, a metal salt of a dicarboxylic acid, a metal alkoxide, an organic salt, an organic acid, or a mixture thereof. 20. The method according to claim 17, wherein the condensation catalyst is a metal salt of a monocarboxylic acid, a metal salt of a dicarboxylic acid, a metal alkoxide, or a mixture thereof. 21. The method according to claim 20, wherein the metal is tin. 22. The method of any of claims 19, 20, or 21, wherein the condensation catalyst is present in an amount of about 0.001 to about 2 parts by weight per 100 parts by weight of polydiorganosiloxane. 23. The method of claim 16, wherein the metal chelate is a metal selected from the group consisting of lead, tin, zirconium, antimony, zinc, chromium, cobalt, nickel, aluminum, gallium, germanium and titanium. 24. The method according to any one of claims 16, 17, 18, or 21, wherein the metal chelate is a titanium chelate. 25. Titanium chelate is polydiorganosiloxane 10
23. The method of claim 22, wherein the method is present in an amount of about 0.05 to about 2 parts by weight per 0 parts by weight.