GB2073765A

GB2073765A - Coating Composition for Use in a Transfer Adhesive System

Info

Publication number: GB2073765A
Application number: GB8108500A
Authority: GB
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1980-03-24
Filing date: 1981-03-18
Publication date: 1981-10-21
Also published as: JPS56155257A; BE888096A; DE3111464A1; AU6867181A; FR2478657A1

Abstract

A coating composition for rendering a material non-adherent to normally adherent high-phenyl content pressure sensitive adhesives comprising (i) 100 parts by weight of a silicon composition comprising (a) 100 parts by weight of a vinyl chain- stopped diorganopolysiloxane base from 50 to 100,000 centipose at 25 DEG C; (b) 0.1 to 10 parts by weight of a trimethyl chain-stopped polymethylhydrogen siloxane fluid cross-linking agent having from 10% to 100% by weight SiH groups and having a viscosity in the range of 25 to 1000 centipose at 25 DEG C; (c) an effective amount of platinum catalyst for facilitating a heat cure hydrolisation reaction, and (ii) 2.0 to 10 parts by weight of silicone resin. The composition can be applied to a base element of metal, foil, glass, plastic paper or fibrous materials.

Description

SPECIFICATION Transfer Adhesive System The present invention relates to polysiloxane compositions which are particularly well-suited for release coating applications and are especially useful for transfer adhesive applications when used in conjunction with polysiloxane adhesives having a high-phenyl content.

Release coatings are useful whenever it is necessary to provide a surface or material which is relatively non-adherent to other materials which would normally adhere thereto. Silicone paper release compositions are widely used as coatings which release pressure sensitive adhesives for labels, decorative laminates, transfer tapes, etc. Silicone release coatings on paper, polyethylene, Mylar and other such substrates are also useful as non-stick surfaces for food handling and industrial packaging applications. Such release coatings ordinarily come in solventless form or as a dispersion in a solvent.

When labels are coated with an adhesive, it is desirable that the paper backing be easily peeled away from the label when it is ready for use, yet the adhesive quality of the label should not be derogated as it is peeled away from the substrate upon which it was stored. The same principle applies to certain types of adhesive tapes which come in rolls. It is necessary that the tape unroll easily and still maintain its adhesive characteristics. This can be accomplished by coating the non-adhesive side of the tape with a silicone release composition, which will come into contact with the adhesive as the roll of tape is manufactured.

Silicone release coatings can be used in conjunction with silicone adhesives in order to form a transfer adhesive system. Such a system can have many applications such as the example shown in the parent application for restoring works of art. In such a system a first substrate, which ordinarily may be any kind of non-porous film or hard surfaced paper and preferably would be supercalendered kraft paper is coated with an MO resin modified solventless silicone release coating which is capable of releasing an aggressive high-phenyl content silicone pressure sensitive adhesive.

Both of these compositions will be described later in the application. The release coating is cured upon the first substrate by well-known means, ordinarily with heat. Increasingly, such curing steps are being initiated by UV or other radiation in order to eiiminate the high cost of thermal cure systems. Next, the high-phenyl content silicone pressure sensitive adhesive is applied upon the release coating and is cured in place such that the first substrate now has two coatings upon it, namely, the silicone release coating and the high-phenyl silicone adhesive. It has been found that the only high-phenyl content silicone adhesive can be utilized in a transfer adhesive system. Ordinary silicone adhesives which are primarily comprised of methyl substituents will not provide the advantageous transfer properties of the present invention.

The doubly coated first substrate is then laminated to a second substrate which is suitable for reinforcing and preserving the work of art. Upon completion of this lamination step, one is left with a transfer adhesive system suitable for reinforcing a work of art at any desired future point in time. The restoration takes place merely by separating the first substrate with its release coating from the second substrate which retains the high-phenyl silicone pressure sensitive adhesive, since the aggressive adhesive is much more adherent to the second substrate than it is to the release coating to which it was in contact. Thus, the high-phenyl silicone adhesive has been transferred from the release coated substrate and one is ieft with the reinforcing second substrate which is now coated with the high phenyl content silicone pressure sensitive adhesive.This reinforcing substrate may then be laminated to the work of art.

Of course, such an adhesive transfer system is not limited to the restoration of paintings, but may be utilized whenever it is desirable to apply a fully-cured pressure sensitive adhesive to nearly any sort of substrate. Once the adhesive has been transferred, it is immediately ready for use when moderate amounts of pressure are applied.

A further advantage of a silicone transfer adhesive system is its wide range of temperature flexibility. Such flexibility is not found in organic adhesives such as acrylics or epoxies which are ineffective adhesives when applied to a substrate which ordinarily reaches relatively high or low temperatures. For example, a high-phenyl content silicone transfer adhesive system would be particularly useful if one desired to apply an adhesive to an engine. Organic adhesives will often peel, crack or otherwise fail to successfully adhere to such a substrate. However, the silicone adhesive can be coated onto its release-coated transfer substrate and cured thereon whereupon it can later be transferred to the hot engine part leaving the adhesive in place.A high-phenyl content silicone pressure sensitive adhesive is capable of withstanding the normally high temperatures which an engine could experience. A label or other laminate could then be applied to such an adhesive.

The present invention provides a silicone transfer adhesive system comprised of (a) a high-phenyl content silicone pressure sensitive adhesive which can be utilized as a transfer film; and (b) an MQ resin modified silicone release coating composition which is effective for releasing the high-phenyl content adhesive thus facilitating its use in a transfer system.

The silicone materials which are particularly well-suited for use in the present invention are various chemical compositions which characteristically have a plurality of silicon to oxygen bonds in a chain or lattice framework. Silicone has a valence of four but when there are less than four oxygen, the remainder are filled with substituted or unsubstituted organic groups. Depending upon the particular combination of silicone, oxygen and organ-substituents, a wide range of silicone fluids and resins can be produced, each of which has different desirable properties. Thus, there is an extremely large number of silicone compositions, some of which are available from several manufacturers and some of which are proprietary with a single manufacturer.

For example, the transfer adhesive system of the present invention utilizes a silicone release coating which is capable of releasing a high-phenyl content silicone pressure sensitive adhesive. A release coating is a silicone composition which can be coated on a substrate (ordinarily paper) and when cured thereof it will adhere vigorously. However, the exposed source of the cured release coating can be coated or contacted with an adhesive or an adhesive coated second substrate, yet it will not aggressively adhere thereto. Thus, the release coated first substrate can be peeled away from the adhesive coated second substrate, leaving the adhesive intact on the second substrate. By this means it would be an easy matter to laminate an adhesive coated substrate to any desired object.

One example of a silicone release coating is that described byckberg in cope ding U.S. Patent Application S.N. 40,015 filed May 17, 1979, which is hereby incorporated by reference.Eckberg's silicone release coating is basically a combination of (a) diorganopolysiloxane base polymer having up to approximately 20% by weight alkenyl or silanol functional groups and having a viscosity ranging from approximately 50 to approximately 100,000 centipoise at 250C; (b) a polymethylhydrogen siloxane fluid cross-linking agent having up to approximately 100% by weight SiH groups and having a viscosity in the range of approximately 25 to approximately 1000 centipoise at 250C; (c) an effective amount of precious metal catalyst for facilitating an addition cure hydrosilation reaction between said base polymer and said cross-linking agent; and (d) an amount of dialkyi carboxylic ester effective to inhibit the precious metal catalyzed hydrosilation cure reaction of said silicone composition at temperatures below the heat cure treatment of said silicone composition.

A more specific example of this silicone release coating is one which contains (a) a vinyl chainstopped polydimethylmethylvinyl siloxane gum containing approximately 20% by weight vinyl groups and having a viscosity of approximately 100,000 centipoise at 250C; (b) a trimethyl chain-stopped polymethylhydrogen siloxane cross-linking fluid having approximately 10 to 100% by weight SiH groups and a viscosity of approximately 25 to 1000 centipoise at 250C; (c) approximately 10 to 500 ppm platinum in the form of a platinum complex catalyst; and (d) approximately 0. 1% to 0.5% by weight diallyl maleate.

This silicone release coating is available from the Silicone Products Division of the General Electric Company, and for the sake of convenience it will hereinafter be referred to as "Release Coating A".

This release coating must be modified in order to provide release properties when one wishes to use an aggressive silicone adhesive having a high-phenyl content as will hereinafter be described.

Release Coating A is modified with an additional amount of MQ silicone resin effective for releasing this particular adhesive. In the silicone art, an MQ resin refers to a polysiloxane product having primarily monofunctional and quadri- or tetra-functional structural units. For a general discussion, see Chapter One of Noll, Chemistry and Technology of Silicones, 2nd ed. 1968.

The MQ resin is obtained from condensed waterglass or sodium silicate and is made up of M units (R3SiO,/2) and 0 units (six2) having an M to Q ratio of approximately 0.5 to 1.0 and preferably about 0.65. The R group denotes monovalent hydrocarbon radicals, especially lower alkyl groups like methyl.

When Release Coating A is modified with approximately 2.0 tm 10 parts by weight of the abovedescribed MO resin it becomes particularly effective for releasing the high-phenyl content silicone pressure sensitive adhesive. This MO modified version of Release Coating A will be referred to as "Release Coating B". Thus it is through the use of this specially modified release coating that one is able to utilize a normally aggressive high-phenyl content adhesive as a transfer film.

Several useful embodiments of the present invention are demonstrated by its varied uses in industry. Take for instance a manufacturer who requires that certain articles be adhesive yet the articles themselves are inherently difficult to coat directly. Several examples which come to mind include silicone rubber parts, or any ojects which have a surface which is sensitive to the solvents normally associated with adhesives.

A common example relates to adhesive-coated sponges. These sponges have many uses, as for instance as cushions in sophisticated electronic equipment. However, a sponge-like surface is extremely difficult to coat by common processes. Therefore, in order to render adhesive such a spongelike surface, there can be employed a Transfer Film System utilizing the adhesive and coatings and methods of the present invention.

In other words, a film of a pre-crosslinked high performance, high-phenyl content silicone adhesive can be deposited intact upon the hard to coat substrate rendering it adhesive as well as providing all of the advantageous properties of silicone pressure sensitive adhesives such as its wellknown wide temperature capabilities.

A Transfer Film System operates in the following manner. Two-sided coated paper or doubly coated paper is utilized as the substrate for storing the adhesive prior to use. This substrate, which ordinarily could be super-calendered Kraft paper, is coated with Release Coating B, a silicone release coating which is capable of releasing the high phenyl content silicone pressure sensitive adhesive utilized by the present invention.

This release coating is essentially a silicone composition which is capable of rendering substrates relatively non-adherent to some other substrate. The release coating can be applied to both sides of the paper since ordinarily the paper will be in the form of long strips which may be rolled.

Upon one side of the doubly release coated paper is applied the high performance, high-phenyl content silicone pressure sensitive adhesive. This adhesive is pre-cured or pre-crosslinked upon the release coating by well-known means. Thus, a film of the pressure sensitive adhesive is formed upon the entire release coated surface. This adhesive film is now ready for use, but ordinarily it is stored in rolls. Of course, since the reverse side of the coated paper is also coated with the release coating, the adhesive can be safely rolled-up without fear that it will be in any way derogated.

Later, when the coated paper is unrolled, the film of the adhesive remains on the surface upon which it was orginally coated. The adhesive film is again ready for use. Now the film can be applied to a heretofore difficult to coat surface such as the sponge mentioned above. The adhesive film coated release paper can be applied to the desired surface or substrate and moderate pressure can be utilized to cause the film to adhere to such a surface. Next, the release coated paper which is relatively less adherent than the sponge or other surface can be peeled away. The pre-crosslinked adhesive film remains upon the new surface rendering it adhesive. Now the adhesive coated surface can be applied to any desired location whereupon moderate amounts of non-destructive pressure will activate the pressure sensitive silicone adhesive characteristics of the material.Thus, the adhesive coated sponge can now be applied to a workpiece to achieve the desired effect.

Of course, it will be recognized that this Transfer Film System can be utilized in other forms besides rolls. If it is utilized "sandwich style" it can provide sheets of adhesive film rather than strips. In this case the high-phenyl content silicone pressure sensitive adhesive is applied and cured upon a sheet of paper which is coated on but one side with the effective release coating. A second release coated sheet is laminated on top of the adhesive to form the sandwich.

Thus, utilization of a Transfer Film System enables a user to render almost any object adhesive.

The compositions and processes of the present invention can also be utilized in a Transfer Tape System which is similar to the Transfer Film System described above but which has several different uses.

In such a system a paper or other substrate is again coated with the silicone release coating and once again upon this coating is applied and cured the high-phenyl content silicone pressure sensitive adhesive which is capable of being utilized in such a transfer system. Upon this pre-cross-linked adhesive is laminated a new substrate which can be selected from a number of materials which are generally limited only by what the user wishes to render adherent Such materials can include Mylar and other polyester films, teflon and teflon coated surfaces, polyethylene films, non-release coated paper such as label stock, etc.

When the release coated paper is peeled away from the new substrate, the adhesive will have been transferred to the relatively more adherent new substrate which has now been rendered adhesive.

It is now ready for any of several uses such as labels, decals, wrapping and other high performance applications which require the advantages of silicone adhesives, as well as the art restoration methods of the parent case.

One obvious advantage of the Transfer Tape System is that the adhesive has been applied and precured upon the release coating prior to lamination with the new substrate. This is an advantage because it is often difficult to cure or coat adhesives upon certain surfaces. For example, the heat necessary to cure an adhesive might be well above the amount tolerable by a plastic film.

This system is called Transfer Tape because the adhesive coated substrate, which is protected by the release coated paper or backing can be rolled-up.for storage, and peeled in tape-like fashion when it is ready for use.

An example of a silicone pressure sensitive adhesive, is found in U.S. Patent 3,929,794-- Horning, which is hereby incorporated by reference. Such- an adhesive can have various substituent ingredients in order to provide desirable properties for different applications such as the excellent wide range temperature flexibilities discussed above. These adhesives will ordinarly contain a silicone resin, a silicone gum and a catalytic amount of curing agent. Various peroxides are well-known catalysts for these systems. Additionally, there may be included plasticizers, extending fillers, and process aids.

These adhesives can be coated and cured on a substrate by well-known means and will become effective adhesives when sufficient activating pressure is applied.

Silicone pressure sensitive adhesives are ordinarily made up of a high viscosity polydimethyl siloxahe gum in combination with a triorgano chain-stopped MO silicone resin. For example, 100 parts by weight of a silanol chain-stopped polydimethyl siloxane gum having a viscosity ranging from approximately 1 C)0,000 to 100 million can be combined with approximately 50 to 200 parts by weight based on the gum of an MO resin as hereinbelow described, to form the basis of a silicone pressure sensitive adhesive having a viscosity determined by the gum. The ratio of resin to gum will determine the adhesive's ultimate tack, peel, adhesion and dryness properties. Any of several catalyst systems can be utilized, for example, the peroxides and amines. Especially useful are benzoyl peroxide and 2,4 dichlorobenzoyl peroxide.

In order to provide the necessary release and transfer properties, the silicone adhesive must have a high-phenyl content. This means that the polydimethylsiloxane gum utilized in ordinary adhesives, as discussed above, is substituted with a polyalkylarylsiloxane gum. By varying the phenyl content one can achieve satisfactory release from a release coated substrate, and an adhesive film can be transferred intact to a surface to be rendered adhesive.

Release Coating A is comprised of (i) 100 parts by weight a silicone composition which is itself comprised of the following: (a) 100 parts by weight of a vinyl chain-stopped diorganopolysiloxane base polymer having a general formula:

wherein R represents the same or different monovalent hydrocarbon radicals free of unsaturation, R' is a hydrocarbon radical having alkenyl unsaturation, x and y are positive integers such that the vinyl chain-stopped polymer has approximately 0% to 20% by weight R' groups and has a viscosity range of approximately 50 to 100,000 centipoise at 250C;; (b) approximately 0.1 to 10 parts and preferably 3 to 4 parts by weight of a trimethyl chain-stopped polymethyl hydrogen siloxane fluid cross-linking agent having approximately 10 to 100% by weight SiH groups and a viscosity range of approximately 25 to 1000 centipoise at 250C: (c) an effective amount of precious metal catalyst for facilitating a heat cure hydrosilation reaction, ordinarily 10 to 500 ppm platinum can be utilized as a catalyst. If desired, the above ingredients can be further combined with approximately 0.1 to 5.0 parts by weight of a dialkyl carboxylic ester which will effectively inhibit the catalyzed hydrosilation cure reaction at temperatures below the heat cure temperature.These esters can be selected from diallylmaleate, diallylphthalate, diallylsuccinate and dialkyl esters of maleic acid selected from the group consisting of dimethyl maleate, diethyl maleate and silyl maleate. Ordinarily, 0.1 to 0.5% by weight diallylmaleate is quite satisfactory.

The above combination of materials comprise Release Coating A, but in order to render some material non-adherent to a normally adherent and aggressive high-phenyl content silicone pressure sensitive adhesive, Coating A must be modified with an MQ silicone resin to provide Release Coating B of the present invention.

Thus, Coating B contains an additional approximately 2.0 to 10 parts by weight of MQ silicone resin which has an M to 0 ratio of 0.5 to 1.0 wherein M represents (R3SiO/2) units and 0 represents (SlO2) units and R denotes a monovalent hydrocarbon radical, ordinarily methyl.

When Release Coating B is coated and cured by well known means onto a substrate such as metal, foil, glass, plastic, polyester, paper and other fibrous materials, it renders the coated surface non-adhesive. But most importantly, it facilitates the transfer of a film of high-phenyl content adhesive from the Release Coated surface to some other surface which is to be rendered adhesive.

The silicone adhesive transfer system comprises the steps of coating and curing Release Coating B upon a first substrate, which ordinarily would be paper. The paper can be in the form of sheets or rolls, etc. At least one surface of the paper or other substrate must be coated. However if both sides are coated, the doubly coated paper can later be rolled up in tape fashion.

Next, the release coating is itself coated with a coating of the high-phenyi content silicone pressure sensitive adhesive which is then precured or pre-cross-linked by well known means upon the release coating.

The high-phenyl content adhesive is generally an intercondensation mixture of an organopolysiloxane resin and at least one alkyl aryl polysiloxane gum. A specific adhesive would be comprised of 100 parts by weight of a silanol chain-stopped polyalkylarylsiloxane gum having a viscosity of 1 million to 200 million centipoise at 250C and having a 5 to 25 mole percent aryl content. Particularly suitable would be a silanol-stopped polymethylphenylsiloxane gum having a 10 to 1 5 mole percent phenyl content and a viscosity of 26 to 80 poise at X104 at 25 CC. This gum is combined with from 50 to 200 parts by weight of a silicone MO resin, as was described above, having an M to 0 ratio of 0.5 to 1.0.

For example, 100 parts of the above gum can be combined with 120 parts of MO resin where M denotes (CH3)3SiO,/2 and Q denotes (SlO2).

When the silicone adhesive is cured upon the release coating it is ready for use or can be stored for later use.

The first substrate is now doubly coated with the Release Coating B and the adhesive film. Next, the doubly coated substrate can be applied or laminated to a second substrate which is to be rendered adhesive. Then the release coated first substrate is separated or peeled away from the second substrate thereby transferring the high-phenyl content adhesive film to the second substrate. The second substrate is now rendered adhesive and may be laminated to a third .substrate wherever desired, or have some third substrate laminated to it.

The release coated first substrate can be paper such as SCK or other hard surfaced paper, teflon, polyester films, plastic, plastic coated crepe and paper, glass, metal foils, etc.

Of course, it is to be understood that the second substrate can either be the workpiece desired to be rendered adhesive immediately, or it can be a second release coated surface such as the reverse side of doubly release coated tape when storage is desired.

The following examples are given by way of illustration, and do not in any way diminish the scope of the claimed invention.

Example 1 To 20 parts of platinum catalyzed Release Coating A was added 40 parts hexane and 1.66 parts of MO resin having an M to 0 ratio of approximately 0.65. The MO resin was added in the form of a 60% non-volatile MQ resin solution in toluene. This solution was double coated with a No. 5 engraved rod upon super-calendered Kraft paper on a standard lab paper coating machine. The two coats were cured for 30 seconds at 3000F for each coat. A sample of high-phenyl content pressure sensitive adhesive was catalyzed with 2% of 2,4-dichlorobenzoyl peroxide based upon the weight of adhesive solids. A 2 mil solvent-free film of the adhesive was applied to the release coating.The adhesive was cured for 90 seconds at 950C followed by 120 seconds at 1 650C. The release and transfer properties were tested by laminating a 1 in. wide strip of 2 mil Mylar to the adhesive. The paper was clamped into an Instron test machine and a free end of the Mylar was pulled from the paper at a rate of 5.0 in. per minute. There was complete transfer of the cured adhesive film to the Mylar with a normal release peel strength of approximately 80 grams.

Example 2 The test method described in Example 1, was followed except that 3.32 parts of the MQ resin solution was utilized. This effectively doubled the amount of MQ resin added to the release coating.

There was found to be 1 50 gram peel strength on the Instron device and there was a successful transfer of the adhesive from the release coating. This example indicates that a release coating with 20% MO resin solids based on adhesive solids ratio is effective for achieving adequate release properties.

Example 3 The test method described in Example 1, was followed for testing Release Coating A without the addition of the MQ resin. The high-phenyl content silicone pressure sensitive adhesive failed to release from the coating and resulted in the separation of the paper.

Example 4 A portion of supercalendered Kraft paper had cured upon it a coating of a silicone Release Coating B which was modified with 5 parts by weight silicone MQ resin. To this coated paper was applied a coating of a high-phenyl content silicone pressure sensitive adhesive which was cured thereon. The exposed adhesive was then contacted with a teflon coated glass fabric, which is suitable for reinforcing the reverse side of the work of art. Since the bond to the teflon was stronger than to the release surface, when the Kraft paper was removed the adhesive transferred intact to the teflon coated glass fabric. The glass fabric was then laminated to the canvas backing of the work of art with the use of light roller pressure.

Claims

1. A coating composition for rendering a material non-adherent to normally adherent high-phenyl content pressure sensitive adhesives comprising: (i) 100 parts by weight of a silicone composition comprising (a) 100 parts by weight of a vinyl chain-stopped diorganopolysiloxane base polymer having the formula,

wherein R is a monovalent hydrocarbon radical free of unsaturation, R' is a hydrocarbon radical having alkenyl unsaturation, x and y are positive integers such that the vinyl chain-stopped diorganopolysiloxane has from 0% to 20% by weight R' groups, and having a viscosity range from 50 to 100,000 centipoise at 250C; (b) 0.1 to 10 parts by weight of a trimethyl chain-stopped polymethylhydrogen siloxane fluid cross-linking agent having from 10% to 100% by weight SiH groups and having a viscosity in the range of 25 to 1000 centipoise at 250C; (c) an effective amount of platinum catalyst for facilitating a heat cure hydrosilation reaction, and (ii) 2.0 to 10 parts by weight of an MQ silicone resin having an M to Q ratio of 0.5 to 1.0 wherein M represents (R3SiO1/2) units and Q represents (SlO2) units and R denotes a monovalent hydrocarbon radical.

2. A coating composition as claimed in Claim 1, further comprising from 0.1 to 5.0 parts by weight of a dialkyl carboxylic ester effective for inhibiting the precious metal catalyzed hydrosilation cure reaction of said silicone composition at temperatures below the heat cure temperature of said silicone composition.

3. A coating composition as claimed in Claim 2, wherein the dialkyl carboxylic esters are selected from diallylmaleate, diallylphthalate, diallylsuccinate and dialkyl esters of maleic acid selected from the group consisting of dimethyl maleate and silyl maleate.

4. A coating composition as claimed in any one of claims 1 to 3, wherein the amount of catalyst is 10 to 500 parts per million.

5. A coating composition as claimed in any one of claims 1 to 4 including 0.1 to 0.5% by weight diallylmaleate.

6. An article of manufacture comprising a base element bearing a heat cured coating of the composition as claimed in any one of the preceding claims.

7. An article of manufacture as claimed in Claim 6, wherein base element is formed of a material selected from metal, foil, glass, plastic, paper and fibrous materials.

8. A silicone transfer adhesive system comprising the steps of (A) coating a first substrate with a silicone release coating capable of releasing a high-phenyl content silicone pressure sensitive adhesive wherein said silicone release coating is comprised of: (i) 100 parts by weight of a silicone composition comprising, (a) a diorganopolysiloxane base polymer having up to 20% by weight alkenyl functional groups having a viscosity ranging from 50 to 100,000 centipoise at 250C; (b) a polymethylhydrogen siloxane fluid cross-linking agent having up to 100% by weight SiH I groups and having a viscosity in the range of 25 to 1000 centipoise at 25 OC: (c) an effective amount of precious metal catalyst for facilitating an addition cure hydrosilation reaction between said base polymer and said cross-linking agent; and (d) an amount of dialkyl carboxylic ester effective to inhibit the precious metal catalyzed hydrosilation cure reaction of said silicone composition at temperatures below the heat cure temperature of said silicone composition, and (ii) 2.0 to 10 parts by weight of an MQ silicone resin having an M to Q ratio of 0.5 to 1.0 wherein M represents (R3SiO,/2) units and 0 represents (SlO2) units and 1.0 wherein M represents (R3Sl012) units and Q represents SiO2 units and R denotes a monovalent hydrocarbon radical; and curing said release coating on said first substrate; (B) applying to said release coating a coating of a high-phenyi content silicone pressure sensitive adhesive capable of being transferred intact from said release coating, wherein said adhesive is the intercondensation product of a mixture of an organopolysiloxane resin and at least one alkylaryl polysiloxane gum; and curing said adhesive; (C) laminating said doubly coated first substrate to a second substrate.

9. A system as claimed in Claim 8, wherein said second substrate is to be rendered adhesive and further comprising the step of (D) separating said release coated first substrate from said second substrate thereby transferring said high-phenyl content silicone pressure sensitive adhesive to said second substrate.

1 0. A system as claimed in Claim 9, further comprising the step of (E) laminating said adhesive coated second substrate to a third substrate.

11. A system as claimed in Claim 8, wherein said second substrate is a release coated protective liner or the release coated reverse side of said first substrate.

12. A system as claimed in Claim 11, further comprising the steps (D) separating said release coated second substrate from said doubly coated first substrate (E) laminating said doubly coated first substrate to a third substrate to be rendered adhesive and (F) separating said release coated first substrate from said third substrate thereby transferring said high-phenyi content silicone pressure sensitive adhesive to said third substrate.

1 3. A system as claimed in Claim 8, wherein said silicone release coating contains (A) a vinyl chain-stopped dimethyl methylvinyl polysiloxane gum containing approximately 20% by weight vinyl groups and having a viscosity of approximately 100,000 centipoise at 250C; (B) a trimethyl chainstopped methyl hydrogen polysiloxane cross-linking fluid having 10 to 100% by weight SiH groups and a viscosity of 25 to 1000 centipoise at 25 OC; (C) 1 O to 300 ppm platinum catalyst; and (D) 0.1 % to 0.5% by weight diallyl maleate.

14. A system as claimed in any one of claims 8 to 13, wherein said first substrate is selected from the hard surfaced paper, supercalendered Kraft paper, teflon, polyester films, plastic, plastic coated crepe paper, and metal foils.

15. A system as claimed in any one of claims 8 to 14, wherein said high-phenyl content silicone adhesive is comprised of 100 parts by weight of a silanol chain-stopped polyaikylphenylsiloxane gum having a viscosity of 1 million to 200 million centipoise at 250C and having a 5 to 25 mole percent phenyl content, and 50 to 200 parts by weight of a silicone MQ resin having an M to Q ratio of 0.5 to 1.0 wherein M represents (R3SiO112) units and Q represents (SiO2) units and R denotes a monovalent hydrocarbon radical.

1 6. A system as claimed in Claim 15, wherein 100 parts of a silanol-stopped polymethylphenyl- siloxane gum having a 10 to 1 5 mole percent phenyl content and a viscosity of 26 to 80 poise X104 at 250C is combined with 120 parts by weight of said MO resin wherein M represents (CH3)3SiOt/2 units.

1 7. A coating composition as claimed in claim 1, substantially as hereinbefore described in any one of the Examples.

18 A system as claimed in claim 8, substantially as hereinbefore described in any one of the Examples