JPS645628B2 - - Google Patents

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION This invention relates to silicone release coating compositions and other inhibitors. More particularly, the present invention describes the use of polysiloxane compositions as inhibitors for noble metal catalyst-containing polysiloxane compositions, which are particularly suitable for solvent-free silicone release coating compositions.
Blends of dialkyl carboxylic esters having carbon-carbon unsaturation and olefinic carboxylic esters of aliphatic alcohols. Silicone compositions have long been used to render surfaces non-adhesive to other materials to which they would normally adhere. For a long time, these silicone coatings have needed to be applied as a dispersion in a solvent in order to control the viscosity of the coating material to be suitable for coating application. However, although the solvent facilitates the application of the paint, this method is extremely inefficient since the solvent must subsequently be evaporated. In addition to the high energy consumption required for solvent evaporation, pollution control requirements require that solvent vapors be prevented from escaping into the environment, ie, the atmosphere. Solvent removal and recovery therefore necessarily involve extensive equipment and energy consumption. For this reason, solvent-free release coating compositions have been developed. Such compositions are sometimes referred to as 100% solids stripping compositions. The absence of solvents in such compositions reduces the amount of energy required to effect curing and eliminates the need for expensive contamination control equipment. However, the problem of premature gelation inherent to such silicone release coatings must be overcome. Because the typical composition of such coatings consists of a vinyl chain-terminated base polymer, a crosslinker, and a platinum metal catalyst, premature curing or gelation occurs within a short period of time, resulting in a product with an unsatisfactory bottle life. Become. When the composition is ready for use, it is desirable that the catalyst-containing polymer composition have a pot life long enough to permit paint application by the end user. As such, the coating composition contains an inhibitor that effectively inhibits the hydrosilanization addition cure reaction of the composition at ambient temperatures, but does not interfere with curing at elevated temperatures. Examples of inhibitors used in conventional solventless stripping compositions include vinyl acetate, diallyl maleate, and triallyl isocyanurate (TAIC). Eckberg, U.S. Pat. No. 4,256,870, discloses that base polymers such as
A silicone composition comprising an alkyl vinyl polysiloxane based copolymer and a methyl hydrogen crosslinking fluid is disclosed. The composition is catalyzed by platinum or a platinum metal complex, which initiates the addition cure reaction. An inhibitor selected from organic esters of maleic acid is added to the composition to selectively inhibit the curing reaction and provide the coating composition with a fully workable pot life. The silicone rubber compositions disclosed in Eckberg U.S. Pat. No. 4,262,107 combine a silanol-terminated diorganopolysiloxane polymer, a silicone hydride crosslinker, and a rhodium complex catalyst with a low molecular weight silanol-terminated diorganopolysiloxane, and certain acetylenic compounds. , olefinic carboxylic acid esters of aliphatic alcohols, such as vinyl acetate,
A composition combining an inhibitor selected from alkenyl isocyanurates and mixtures of these compounds, which has a good pot life and cures quickly at high temperatures. Solventless platinum or rhodium catalyzed addition-curable polyorganosiloxane release coating compositions disclosed in Eckberg U.S. Pat. No. 4,347,346 incorporate dialkyl acetylene dicarboxylate inhibitors to prevent premature gelation at ambient temperatures. at elevated temperatures through a hydrosilanization reaction to form a coating or coating that enables a material to be peeled from the substrate to which it would normally be adhered. Grenoble and
Eckberg, US Patent Application No. 458,421, discloses novel multicomponent solventless silicone release coating compositions. This patent application discloses a conventional two-component system in which the first component consists of a vinyl silicone fluid, a noble metal catalyst, and an inhibitor, and the second component consists of a polymethylhydrogensiloxane crosslinker, but the end user has The flexibility to reformulate silicone release coatings to precisely meet their performance and cost requirements is unduly limited. Accordingly, multi-component systems are provided in which the components are presented to the end user as three or more separate parts to ensure such flexibility. Although such multicomponent systems virtually eliminate the problem of premature gelation over a long period of time, they also extend the effective pot life of the release coating composition, extending the period over which coating applications can be performed by the end user. It is also desirable to extend it. According to the invention, therefore, a solvent-free silicone release coating containing a two-component inhibitor not only exhibits a stronger inhibitory action than the individual components at equivalent concentrations, but also increases the solubility of such inhibitor in silicone fluids. A composition is provided. Thus, the present invention achieves a significant improvement over conventional release coating compositions containing one-component inhibitors. It is therefore a principal object of the present invention to provide a solvent-free composition which renders a surface non-adhesive to materials to which it would normally adhere. Another object of the invention is to provide a solvent-free coating composition that cures to a coating having favorable properties with respect to staining, scrubbing, migration and peeling. Yet another object of the present invention is to provide a solvent-free coating composition that has a satisfactory pot life or bath life in a catalyst-containing form when ready for use. Yet another object of the invention is to provide a method of rendering a material non-adhesive to other materials to which it would normally adhere. Yet another object of the present invention is to provide a release coating composition containing a two-component inhibitor that effectively inhibits catalytic crosslinking reactions at temperatures below the heat curing temperature of the composition, and particularly for release paper applications. An object of the present invention is to provide a suitable solvent-free silicone composition. These and other objects will be apparent to those skilled in the art upon consideration of the following description and examples of the invention. SUMMARY OF THE INVENTION The present invention provides a silicone release coating composition containing a two-component inhibitor, a dialkyl carboxylic acid ester having carbon-carbon unsaturation and an olefinic carboxylic acid ester of an aliphatic alcohol. is effective in inhibiting noble metal-catalyzed addition-cure hydrosilanization reactions at room temperature, but does not interfere with curing at elevated temperatures. Such two-component inhibitors are suitable for use with stripping paint baths containing high concentrations of catalyst, and are also described in Grenoble and Eckberg, supra.
It is particularly useful for use in the multicomponent systems described in No. 458421. The cured composition adheres strongly to the substrate to which it is applied, such as paper, but is substantially non-adhesive to materials to which it would normally adhere, such as pressure sensitive adhesives. Forms a silicone coating. Release coating compositions containing two-component inhibitors as provided by the present invention can be two-component systems, but preferably include the Grenoble and
It is a multicomponent system of the type disclosed in Eckberg, US Pat. No. 4,584,21. Generally, the release coating composition of the present invention has the following formula: (a) Olefin organopolysiloxane having the structural unit or general formula: (b) a silanol-terminated organopolysiloxane having the following formula: (c) a catalytic amount of a noble metal catalyst, preferably a platinum or rhodium compound, to carry out the co-reaction of components (a) and (b); and (d) an organohydrogenpolysiloxane having structural units of An amount of dialkyl having carbon-carbon unsaturation that is effective in inhibiting the addition cure hydrosilanization reaction between the siloxane and the organohydrogenpolysiloxane, but not sufficient to prevent curing of the coating composition at elevated temperatures. Consisting of a blend of carboxylic acid ester and olefinic carboxylic acid ester of aliphatic alcohol, R in the above formula is an organic group bonded to silicon through a C-Si bond, a monovalent hydrocarbon group, a monovalent halogenated hydrocarbon and cyanoalkyl groups, usually R containing from 1 to 30 carbon atoms in a straight or branched chain, preferably from 1 to
Containing 12 carbon atoms, but preferably 1 to 8 carbon atoms; R ¹ is an olefinic hydrocarbon group bonded to silicon by a C--Si bond, usually containing 1 to 8 carbon atoms in a straight or branched chain. Contains 20 aliphatic carbon atoms, preferably 1 to 12 carbon atoms linked by multiple bonds (e.g. vinyl, allyl, methallyl, butenyl, pentenyl, ethenyl, etc.); a is 0 to 3, preferably is about 0.5
b has a value of from about 0.005 to about 2.0, and the sum of a and b equals from 0.8 to 3, and the release coating composition is fluid at room temperature and about 10 ~5000 centipoise, preferably ~300
It has a viscosity of 1000 centipoise. DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, compositions are obtained which are particularly suitable for rendering materials non-adhesive to other normally adhesive materials, such as glues, adhesives and the like. Additionally, the composition can be applied directly to a support without the need for a solvent, thereby avoiding the aforementioned problems associated with solvent-based release compositions. The addition curable compositions of the present invention can be provided as a mixture of several components, of which at least one component is
Contains more than one species of compound. An example of such a system is described in U.S. Pat. No. 4,256,870, in which the first part includes a vinyl silicone fluid, a noble metal catalyst, and an inhibitor, and the second part consists of a polymethylhydrogensiloxane crosslinker. In such compositions, the inhibitors of the invention exhibit good solubility and the high platinum content of the compositions provides improved bath life. However, the coating composition
Preferably, it is provided as a four-component system, such as that disclosed in US Pat. The above-mentioned U.S. patent application no.
No. 458,421 discloses that the storage stability of release coating compositions is significantly improved when the individual components are stored separately, and that low-temperature curing performance comparable to conventional high platinum two-component systems is achieved by using catalysts. It is taught that significantly lower catalyst concentrations can be achieved as a result of more efficient utilization of . The release coating composition is composed of the above-mentioned components,
heat cures on the support on which it is coated (applied);
The support is rendered substantially non-adhesive. in particular,
The olefin organopolysiloxane having the structural unit represented by the formula is intended to broadly encompass low-viscosity fluid organopolysiloxanes suitable for coatings, preferably, but not necessarily, containing no silane hydrogen; Contains olefinic unsaturation due to double or triple bonds between two adjacent aliphatic carbon atoms. Groups represented by R in the formula include alkyl, such as methyl, ethyl, propyl, isopropyl, butyl, octyl, dodecyl, etc.; cycloalkyl, such as cyclopentyl, cyclohexyl, cycloheptyl, etc.; aryl, such as phenyl, naphthyl, tolyl, xylyl, etc. ; aralkyls, such as phenylethyl, phenylpropyl; halogenated derivatives of the above groups, such as chloromethyl, trifluoromethyl, chloropropyl, chlorophenyl, dibromophenyl, tetrachlorophenyl, difluorophenyl, etc.; and cyanoalkyls, e.g. β-cyanoethyl, γ-cyanopropyl, β-
Examples include cyanopropyl. Preferably R
is methyl. Furthermore, the formula is meant to encompass materials in which R is a mixture of the groups mentioned above. The group represented by R ¹ in the formula includes alkenyl,
Examples include vinyl, allyl, methallyl, butenyl, bentenyl, and the like; and alkynyl, such as ethynyl, propynyl, butynyl, pentynyl, and the like. Preferably R ¹ is vinyl or allyl, most preferably R ¹ is vinyl. Olefin organopolysiloxanes encompassed within the formula are well known in the art and are described, for example, in U.S. Pat. No. 3,344,111 to Chalk and Modic.
No. 3,436,366. The production and commercial availability of these siloxanes is likewise well known. The olefin organopolysiloxane of the formula (1) is: (In the formula, R and R ¹ are as defined above, c has a value of 0 to 2, and the average sum of c and d is equal to 0.8 to 3.0) and (2) structural formula: (wherein R is as defined above and n has a value from 0.8 to 2.5). When the olefin organopolysiloxane used in this invention is a copolymer of an organopolysiloxane having units within the formula range and an average formula within the formula range, the copolymer will generally contain 0.5 to 99.5 mole percent units of the formula Units within the range 0.5~
Contains 99.5 mol%. The preparation of these copolymers is well known to those skilled in the art. The main portion of the composition is typically a vinyl terminated polysiloxane having the general formula: Here, R is a monovalent hydrocarbon group containing no unsaturation. Suitable groups for R are, for example, methyl, ethyl, propyl, butyl and other similar unsaturated hydrocarbons, but usually do not include phenyl groups for release papers. R ¹ is a hydrocarbon group with alkenyl unsaturation. Typically R ¹ represents a vinyl group, but may also represent an allylic or cycloalkenyl unsaturated group. x and y are positive integers such that the vinyl chain-terminated polysiloxane has up to about 20% by weight R ¹ groups. The viscosities of such polysiloxanes range from about 50 to about 100,000 centipoise at 25°C. Preferably, the vinyl chain-terminated polysiloxane has up to about 20% by weight vinyl groups and has a viscosity ranging from about 300 to about 550 centipoise at 25°C. A suitable vinyl chain terminated polysiloxane has the general formula: Here, x and y are as defined above. Silanol chain-terminated linear polydiorganosiloxanes of formula a can be used with or in place of vinyl-containing copolymers of formula. Such silanol-terminated polysiloxanes are produced by equilibration reactions of cyclic polysiloxanes in the presence of alkali metal hydroxide catalysts. The desired viscosity is obtained by controlling the amount of water added to the reaction. Such procedures are described in the literature and are familiar to those skilled in the art. Furthermore, silanol chain-terminated polydimethylmethylvinylsiloxane copolymers can also be envisaged and fall within the scope of the invention. Methyl hydrogen fluid is often used as a crosslinking agent for addition cure silicone systems by those skilled in the art.
Particularly useful as crosslinking agents for the present invention are trimethyl chain-terminated polymethylhydrogen siloxane fluids,
It has about 10 to about 100% SiH groups, and the remaining groups are all dimethylsiloxy groups, and at 25°C it has about 15 to about
It has a viscosity in the range of 1000 centipoise. Organohydrogenpolysiloxanes having structural units represented by the above formula broadly encompass fluid organopolysiloxanes containing silane hydrogen, although preferably, if not necessarily, containing olefinic unsaturation. It is. Organohydrogenpolysiloxanes of the formula are well known in the art and are described, for example, in US Pat. Nos. 3,344,111 and 3,436,366. Among the groups included in R in the formula are alkyl,
For example, methyl, ethyl, propyl, isopropyl, butyl, octyl, etc.; cycloalkyl, such as cyclopentyl, cyclohexyl, cycloheptyl, etc.; aryl, such as phenyl, naphthyl, tolyl, xylyl, etc.; aralkyl, such as phenylethyl, phenylpropyl, etc.; halogenated derivatives of groups such as chloromethyl, trifluoromethyl, chloropropyl, chlorophenyl, dibromophenyl, tetrachlorophenyl, difluorophenyl; and cyanoalkyls such as β-cyanoethyl, γ-cyanopropyl, β-cyanopropyl and so on. Also included within the scope of the formula are those materials in which R is a mixture of the above groups. Preferably the R group of the formula is methyl. Special materials included in the above formula include:
1,3-dimethyldisiloxane and 1,1,
Included are 3,3-tetramethyldisiloxane as well as high polymers containing up to 100,000 or more silicon atoms per molecule. Cyclic substances, for example the following general formula: Also encompassed within the scope of the formula are cyclic polymers of methylhydrogensiloxane having the formula (where x is an integer from 3 to 10 or greater). Particular mention may be made of sym-tetramethylcyclotetrasiloxane. The organohydrogen polysiloxane that can be used in the practice of the present invention has the following formula per molecule: The remaining siloxane units of the organopolysiloxane can also be characterized as copolymers containing at least one unit of . Here, R, c, d and n are as defined above. Within the formula are hydrogen siloxane units (HSiO) _1.5 , methylhydrogen siloxane units (HSiCH ₃ O), dimethylhydrogen siloxane units (HSi[CH ₃ ] ₂ O) and dihydrogen siloxane units (H ₂ SiO). There are siloxane units. In these copolymers, the siloxane units of the formula and are present in such proportions as to form a hydrogen polysiloxane within the above formula. in general,
Such copolymers contain siloxane units of the formula
0.5~99.5 mol% and siloxane units of formula 0.5~
Contains 99.5 mol%. Typically, for release coatings, the organohydrogen polysiloxane crosslinker is essentially a trimethyl chain-terminated methylhydrogen polysiloxane fluid having a viscosity of about 10 to 500 centipoise at 25°C and a hydrogen content of about 0.1 to 1.67% by weight. It is preferable to have one. The noble metal catalyst components used in the compositions of the present invention include the well-known platinum and rhodium which are effective in promoting the reaction between silicon-bonded hydrogen atoms and silicon-bonded olefin groups and are freely miscible in solvent-free silicone polymers. Includes all catalysts. These materials include, among others, the platinum hydrocarbon complexes described in U.S. Pat. No. 3,159,601 and 3,159,662 to Ashby, the platinum alcoholate catalysts described in U.S. Pat.
Examples include platinum catalysts described in US Pat. No. 3,814,730. In addition, Modic's U.S. patent no.
The platinum chloride-olefin complexes described in No. 3,516,946 are also useful in the present invention. All of these US patents are prior art documents to the present invention. The cure reaction that occurs between the vinyl functional polysiloxane and the polymethylhydrogen siloxane fluid crosslinker is an addition cure reaction, also known as hydrosilanization. The compositions of the present invention can be thermally cured by a platinum-catalyzed crosslinking reaction between the vinyl side groups of the dialkyl vinyl chain-terminated polydialkyl-alkyl vinyl siloxane copolymer and the trimethyl chain-terminated polymethyl hydrogen fluid. A particularly useful catalyst for promoting this hydrosilanization reaction is described in U.S. Pat. No. 3,814,730.
Karstedt's catalyst. Other platinum metal catalysts can be used in the practice of this invention, but the selection will depend on factors such as the required reaction rate, cost, useful pot life, and the temperature at which the curing reaction is to occur. Other metal catalysts useful in the present invention include silicone soluble complexes of the metals rhodium, ruthenium, palladium, osmium, iridium and platinum. In the coating compositions of the present invention, the amount of catalyst ranges from about 10 to about 500 ppm (by weight of metal atoms), again depending on factors such as reaction rate, cost considerations, and the like. The amount of catalyst is about 10~ in terms of precious metals.
It is preferable to set it to 150 ppm. It is desirable to include an inhibitor in the coating composition package to substantially eliminate premature curing or gelling problems. Surprisingly, carbon-
Inhibitors consisting of blends of dialkyl carboxylic esters with carbon unsaturation and olefinic carboxylic esters of aliphatic alcohols are more effective as inhibitors than equivalent amounts of the individual components used alone, especially for high platinum It has been found to be effective in high content (ie, low curing temperature) systems. A high platinum content or low curing temperature system means that the catalyst-containing bath is
This means containing 50 ppm or more of a noble metal catalyst, typically 100 ppm or more of a noble metal catalyst. Such two-component inhibitors include the aforementioned Grenoble and
It is also particularly useful in the multicomponent packaging systems of Eckberg, US Pat. No. 4,584,21. This inhibitor allows the end user to tailor the formulation of the release coating composition to meet specific needs. Furthermore, the inhibitors of the present invention are advantageous over conventional one-component inhibitors for use in low temperature curing release coating systems. The reason is as follows. For example, diallyl maleate is a polar material and is not readily soluble in silicone fluids at concentrations greater than about 0.3% by weight.
However, in the present invention, vinyl acetate acts both as an inhibitor and as a mutual solvent for both diallyl maleate and silicone fluids, thus making it more preferred to use the inhibitor at concentrations that would otherwise be impractical. I can do it. Eckberg, U.S. Pat. No. 4,256,870, discloses that a dialkyl carboxylic acid ester having a specified amount of carbon-carbon unsaturation inhibits noble metal catalyzed hydrosilanization curing reactions at temperatures below the thermal curing temperature of the release coating composition. It has been disclosed that it is effective. Most preferably, the dialkyl carboxylic ester has the formula: diallyl maleate (i.e., diallyl maleate), and is usually used in a range of about 0.1 to about 0.5% by weight. Other suitable diallylic carboxylic acid esters include diallyl phthalate (ie, diallyl phthalate) and diallyl succinate (ie, diallyl succinate). Saturated dialkyl esters of maleic acid, such as diethyl maleate and dimethyl maleate, and mixed esters, such as butyl allyl maleate and methyl ethyl maleate, are also useful as hydrosilanization inhibitors for solventless release coating compositions. . Other useful inhibitors are also found in the Eckberg patent, cited above. The use of olefinic carboxylic acid esters of aliphatic alcohols is also described in U.S. Pat. No. 4,262,107 to Eckberg.
It is disclosed as a prohibited agent for silicone rubber compositions containing rhodium catalyst. This patent includes:
Silanol-based polymers with such inhibitors
It is taught that concentrations as low as 0.1 to 2 parts per 100 parts may be used and should preferably be used at concentrations of 0.5 to 1.5 parts per 100 parts of silanol-based polymer. A preferred inhibitor compound is vinyl acetate, where the alcohol has 1 to 4 carbon atoms and the olefinic carboxylic acid has 2 to 10 carbon atoms.
Olefinic carboxylic acid esters of aliphatic alcohols having 5 carbon atoms are within the scope of the patent. The above patents are also considered prior art documents to the present invention and are assigned to the applicant. The present invention provides that blends of dialkyl carboxylic esters having carbon-carbon unsaturation and olefinic carboxylic esters of aliphatic alcohols are more effective inhibitors than equivalent amounts of the individual components used separately. That is, this was made based on the unexpected discovery that a synergistic effect can be obtained by blending such inhibitors. Although diallyl maleate is the most preferred dialkyl carboxylic ester containing carbon-carbon unsaturation, any of the inhibitor compounds within the scope of US Pat. No. 4,256,870 may be used in the present invention. Suitable inhibitor compounds that can be used include butyl allyl maleate, diallyl succinate, dimethyl maleate, diethyl maleate and silyl maleate, such as those of the formula: Bis-γ-propyltris(methoxy) with
There is silyl maleate. Although vinyl acetate is the most preferred olefinic carboxylic acid ester of aliphatic alcohol, any of the inhibitor compounds within the scope of US Pat. No. 4,262,107 may also be used in the present invention.
More specifically, inhibitor compounds of this type include 1 to
aliphatic alcohol having a number of carbon atoms of 4 and 2
It is derived from olefinic carboxylic acids having ~10 carbon atoms. A dialkyl carboxylic ester having carbon-carbon unsaturation, preferably diallyl maleate or butylallyl maleate, is mixed with an olefinic carboxylic ester of an aliphatic alcohol, preferably vinyl acetate, in a range from about 1:24 to 1:1. The ratio is most preferably about 1:3. Accordingly, a most preferred inhibitor for the release coating composition of the present invention is a blend consisting of 1 part diallyl maleate and 3 parts vinyl acetate. It has been found that small amounts of such two-component inhibitors provide an exceptionally long post-catalyst pot life without sacrificing curing performance, especially in compositions with high platinum content. Generally, effective amounts of inhibitors range from 0.05 to about 2% by weight, preferably from 0.1 to 1.5% by weight. Pot life is improved as a result of using the present invention, and the composition cures rapidly upon heat curing to provide a clean, migration-free, non-adhesive surface. The improved inhibitors of this invention can be applied to conventional two-package systems. That is, the inhibitor can be stored in a first container containing the inhibitor blend, vinyl silicone fluid, and precious metal catalyst, while the polymethylhydrogensiloxane crosslinker is stored in a separate container. However, it is preferred to use ternary or multicomponent package systems, such as those disclosed in Grenoble and Eckberg, US Pat. No. 4,584, supra. Thus, in addition to the improved pot life, the inhibitor blends of the present invention also provide very long storage stability if each of the components is stored in separate containers. In addition to the components mentioned above, it is also within the scope of the invention to include other components. One preferred additional ingredient is a vinyl gum accelerator of the type disclosed in Eckberg, US Pat. No. 4,340,647.
This patent discloses that dimethylvinyl chain-terminated polydimethylmethylvinylsiloxane polymer gums facilitate hydrosilanization curing reactions at relatively low temperatures without sacrificing performance. Such vinyl gums can also be loaded alone or preferably together with the base polymer. To enable those skilled in the art to better practice the invention, the following examples are presented by way of illustration and not by way of limitation. DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples 1-4 In the following examples, release coating compositions were prepared from the following ingredients. (A) Linear dimethylvinyl chain-terminated polydimethylsiloxane fluid 100 with a viscosity of 120 cps at 25°C.
and 5 parts of a dimethylvinyl chain-terminated linear polydimethylmethylvinylsiloxane copolymer gum having a molecular weight of about 300,000 and containing 0.2 mole % methylvinylsiloxane units;
A mixture with a viscosity of approximately 400 cps at 25°C. (B) A solution of a platinum catalyst in a dimethylvinyl-terminated polydimethylsiloxane fluid having a viscosity of 300 cps at 25°C, wherein the catalyst is present in an amount sufficient to provide 1800 ppm platinum (in terms of metal) to the solution. solution. (C) A trimethylsiloxy chain-terminated linear polymethylhydrogen siloxane fluid having a viscosity of about 20-40 cps at 25°C as a crosslinking agent. (D) A blend of 3 parts vinyl acetate and 1 part diallyl maleate. Initial experiments were conducted by preparing a release coating composition bath as shown in Table 1.

TABLE The viscosity of four release paint baths was monitored as a function of time at 25° C. under static conditions over a period of 7 hours. The results shown in Table 1 demonstrate that the two-component inhibitors of this invention provide release paint baths with satisfactory pot life. Note that for the purposes of this experiment, the crosslinker was added at time zero.

[Table] It can be seen that various amounts of diallyl maleate/vinyl acetate inhibitor provide a satisfactory pot life while effectively controlling the rate of viscosity increase of the catalyst addition bath, independent of the absolute amount of catalyst. Examples 5 and 6 In this example, two baths were made that were the same as in Example 1, except containing only one of the inhibitor blends used in Example 1. The compositions of these release paint baths are shown in Table 1.

Table: Again, the viscosity of these two release paint baths was monitored as a function of time at 25° C. under static conditions for 7 hours. The results are shown in Table 1.

[Table] Although the viscosity of each bath doubled in approximately 4 hours, these results indicate that the total inhibitor concentration in the bath of Example 1 was higher than that in the bath of either Example 5 or Example 6. It is not an abnormal value in the sense that it is higher than the amount of inhibitor compounded. Examples 7-9 Experiments were conducted to examine the effectiveness of individual inhibitors in amounts comparable to those of the two-component inhibitor used in Example 1. The compositions of these release paint baths are shown in Table 1.

TABLE The viscosity of these release paint baths was again monitored as a function of time at 25° C. under static conditions over a period of 7 hours. The results are shown in Table 1.

[Table] As can be seen from these results, the mixed diallyl maleate/vinyl acetate inhibitor is significantly superior to the inhibitory effect of vinyl acetate alone. Although the bath composition of Example 8 has a satisfactory bath life, it is not useful for low temperature curing applications like the bath of Example 4. Furthermore, even if the composition requires high temperature curing,
The inhibitor blends of the present invention exhibit improved solubility, thus allowing more favorable concentrations of inhibitor to be used. Next, a release paint bath with a high platinum content, ie, a release paint bath with a platinum content comparable to that of Example 4, was prepared and the efficacy of diallyl maleate in such a bath was investigated. The composition of this bath is shown in Table 1. Table Bath Example 9 Component A 150.0 g Component B 12.5 Component C 6.0 DAM 0.49 (0.3%) Pt, ppm 134 The viscosity of the bath was monitored as a function of time at 25° C. under static conditions for 7 hours. The results are shown in Table 1. Bath Example 9 Initial 350 cps 2 hours 590 4 hours 1200 7 hours Gel Although diallyl maleate alone is not effective for use in high platinum release coating composition baths, the two - component inhibitor of the present invention may be used instead. It can be seen that the bath used exhibits a useful pot life of over 7 hours. Although the examples and claims described in U.S. Pat. No. 4,256,870 refer to silicone compositions that inhibit premature curing in the presence of high levels of platinum due to diallyl maleate alone, No. 3,220,972
It should be understood that Lameroux is a catalyst. It was determined that Lameroux's catalyst was not effective in promoting industrially useful curing rates at temperatures below 250°C, even at platinum concentrations as high as 200ppm. For example, in U.S. Pat. No. 4,256,870,
It is disclosed that a composition containing 200 ppm Lameroux's catalyst and 0.5% diallyl maleate takes 40 seconds to cure at 250°. On the other hand, with Karstedt or Ashby type catalysts,
Curing is possible within 30 seconds at temperatures as low as 200° and in the presence of 100-200 ppm of platinum catalyst. Diallyl maleate alone at high concentrations (>3000 ppm) is not compatible with Karstedt or Ashby platinum catalysts at high concentrations (i.e., >100 ppm Pt) and causes rapid precipitation of insoluble platinum residue. Further research has determined that diallyl maleate alone is not suitable as an inhibitor in either the high platinum content compositions or the multicomponent systems of Grenoble and Eckberg, US Patent Application No. 4,584, supra.

Claims (1)

[Scope of Claims] 1 (a) Olefin organopolysiloxane or silanol trailing diorganopolysiloxane.
a base polymer, (b) an organohydrogenpolysiloxane crosslinker, (c) a catalytic amount of a noble metal catalyst, and (d) a blend of a dialkyl carboxylic acid ester having carbon-carbon unsaturation and an olefinic carboxylic acid ester of an aliphatic alcohol. A composition containing an effective amount of an inhibitor comprising: 2 The above olefin organopolysiloxane has the following formula: The organohydrogen polysiloxane has the following formula: wherein R is selected from the group consisting of monovalent hydrocarbon groups, monovalent halogenated hydrocarbon groups, cyanoalkyl groups and mixtures thereof, and has 1 to 30 carbon atoms. is an organic group,
R ¹ is an olefinic hydrocarbon group having 1 to 20 carbon atoms, a has a value of 0 to 3, b has a value of about 0.005 to about 2.0, and the sum of a and b is 0.8～3
The composition of claim 1, wherein the coating composition is a fluid having a viscosity at 25°C ranging from about 10 to 5000 centipoise. 3. The composition of claim 2, wherein R is methyl. 4. The composition according to claim 2, wherein R ¹ is vinyl or allyl. 5 The above olefin organopolysiloxane is 25
The composition of claim 1 which is a dimethylvinyl chain-terminated dimethylvinyl polysiloxane copolymer fluid having a viscosity of about 100 to 1000 centipoise at °C and a vinyl content of less than 2.5% by weight. 6 The above organohydrogen polysiloxane has a temperature of approx.
The composition of claim 1 which is a trimethyl chain-terminated methylhydrogen polysiloxane fluid having a viscosity of 10 to 500 centipoise and a hydrogen content of about 0.1 to 1.67% by weight. 7 The above noble metal catalyst is platinum metal, rhodium metal,
2. The composition of claim 1, wherein the composition is selected from the group consisting of platinum metal complexes and rhodium metal complexes. 8. The composition of claim 7, wherein said noble metal catalyst is present in an amount sufficient to provide about 5 to 500 parts of platinum or rhodium metal per million parts of olefin organopolysiloxane. 9. The composition of claim 7, wherein said noble metal catalyst is present in an amount sufficient to provide about 50 to 500 parts of platinum or rhodium metal per million parts of olefin organopolysiloxane. 10 A patent in which the dialkyl carboxylic acid ester is selected from the group consisting of diallyl maleate, butylallyl maleate, diallyl succinate, and dialkyl ester of maleic acid selected from the group consisting of dimethyl maleate, diethyl maleate, and silyl maleate. A composition according to claim 1. 11. The composition according to claim 1, wherein the dialkyl carboxylic acid ester is diallyl maleate. 12. The olefinic carboxylic acid ester of an aliphatic alcohol is formed from an alcohol having 1 to 4 carbon atoms and an olefinic carboxylic acid having 2 to 10 carbon atoms. Composition. 13. The composition according to claim 1, wherein the olefinic carboxylic acid ester of aliphatic alcohol is vinyl acetate. 14. The composition of claim 1, wherein said dialkyl carboxylic ester is blended with said olefinic carboxylic ester of aliphatic alcohol in a ratio of from about 1:24 to about 1:1. 15. The composition of claim 1, wherein the dialkyl carboxylic acid ester is blended with the olefinic carboxylic acid ester of aliphatic alcohol in a ratio of about 1:3. 16 Diallyl maleate and vinyl acetate about 1:
The composition according to claim 1, wherein the composition is formulated in a ratio of 3:3. 17. The composition of claim 1, wherein said inhibitor is present in an amount ranging from about 0.05 to 2% by weight. 18. The composition of claim 1, wherein said inhibitor is present in an amount ranging from about 0.1 to 1.5% by weight. 19 (a) a dimethylvinyl chain-terminated dimethylmethylvinyl polysiloxane copolymer fluid having a viscosity of about 100 to 1000 centipoise at 25°C and a vinyl content of about 0.1 to 2.5% by weight; (b) a viscosity of about 10 to 500 centipoise at 25°C. (c) a group consisting of platinum metal, rhodium metal, complexes of platinum metal and complexes of rhodium metal, with a viscosity of 5 to 500 ppm as precious metals; and (d) an inhibitor consisting of 0.05 to 2% by weight of a blend of diallyl maleate and vinyl acetate in a ratio of about 1:3. Composition of. 20 In rendering the surface non-adhesive to materials to which it would normally adhere, A. c) a catalytic amount of a noble metal catalyst to promote the co-reaction of components (a) and (b), and (d) a blend of a dialkyl carboxylic acid ester having carbon-carbon unsaturation and an olefinic carboxylic acid ester of an aliphatic alcohol. A silicone release coating composition is prepared by combining an effective amount of an inhibitor consisting of: B applying the silicone release coating to a suitable support, and C applying the silicone release coating to the cure inhibiting ability of the inhibitor. A method of rendering a surface non-adhesive comprising the step of curing with an effective amount of heat to overcome the problem. 21 The above olefin organopolysiloxane has the following formula: The organohydrogen polysiloxane has the following formula: wherein R is selected from the group consisting of monovalent hydrocarbon groups, monovalent halogenated hydrocarbon groups, cyanoalkyl groups and mixtures thereof, and has 1 to 30 carbon atoms. is an organic group,
R ¹ is an olefinic hydrocarbon group having 1 to 20 carbon atoms, a has a value of 0 to 3, b has a value of about 0.005 to about 2.0, and the sum of a and b is 0.8～3
21. The method of claim 20, wherein the coating composition is a fluid having a viscosity within the range of about 10 to 5000 centipoise at 25<0>C. 22. The method of claim 21, wherein R is methyl. 23. The method of claim 21, wherein R ¹ is vinyl or allyl. 24 The above olefin organopolysiloxane is
Viscosity of about 100-1000 centipoise at 25°C and approx.
21. The method of claim 20, wherein the fluid is a dimethylvinyl chain-terminated dimethylmethylvinyl polysiloxane copolymer fluid having a vinyl content of 0.1 to 2.5% by weight. 25 The organohydrogenpolysiloxane has a viscosity of about 10 to 500 centipoise at 25°C and a viscosity of about 0.1 to 1.67
21. The method of claim 20, wherein the fluid is a trimethyl chain-terminated methylhydrogen polysiloxane fluid having a hydrogen content of % by weight. 26. The method of claim 20, wherein the noble metal catalyst is selected from the group consisting of platinum metal, rhodium metal, complexes of platinum metal, and complexes of rhodium metal. 27. The method of claim 26, wherein said noble metal catalyst is present in an amount sufficient to provide about 5 to 500 parts of platinum or rhodium metal per million parts of olefin organopolysiloxane. 28. The method of claim 26, wherein said noble metal catalyst is present in an amount sufficient to provide about 50 to 500 parts of platinum or rhodium metal per million parts of olefin organopolysiloxane. 29 A patent in which the dialkyl carboxylic acid ester is selected from the group consisting of diallyl maleate, butyl allyl maleate, diallyl succinate, and dialkyl ester of maleic acid selected from the group consisting of dimethyl maleate, diethyl maleate, and silyl maleate. The method according to claim 20. 30. The method of claim 20, wherein the dialkyl carboxylic acid ester is diallyl maleate. 31. Claim 20, wherein the olefinic carboxylic acid ester of aliphatic alcohol is formed from an alcohol having 1 to 4 carbon atoms and an olefinic carboxylic acid having 2 to 10 carbon atoms. Method. 32. The method according to claim 20, wherein the olefinic carboxylic acid ester of aliphatic alcohol is vinyl acetate. 33. The method of claim 20, wherein said dialkyl carboxylic ester is combined with said olefinic carboxylic ester of aliphatic alcohol in a ratio of from about 1:24 to about 1:1. 34. The method of claim 20, wherein said dialkyl carboxylic ester is blended with said olefinic carboxylic ester of aliphatic alcohol in a ratio of about 1:3. 35 Diallyl maleate and vinyl acetate about 1:
21. The method according to claim 20, wherein the ingredients are blended in a ratio of 3:3. 36. The method of claim 20, wherein said inhibitor is present in an amount ranging from about 0.05 to 2% by weight. 37. The method of claim 20, wherein said inhibitor is present in an amount ranging from about 0.1 to 1.5% by weight. 38 Claim 2 in which the support is paper
The method described in item 0. 39. The method of claim 20, wherein the silicone release coating composition comprises: (a) a viscosity of about 100 to 1000 centipoise at 25°C and a vinyl content of about 0.1 to 2.5% by weight; (b) a trimethyl chain-terminated methylhydrogen polysiloxane fluid having a viscosity of about 10 to 500 centipoise at 25°C and a hydrogen content of about 0.1 to 1.67% by weight; (c) a precious metal. 5 to 50 ppm of a noble metal catalyst selected from the group consisting of platinum metal, rhodium metal, complexes of platinum metal and complexes of rhodium metal,
and (d) an inhibitor consisting of 0.05 to 2% by weight of a blend of diallyl maleate and vinyl acetate in a ratio of about 1:3.