KR19980064771A - Silicone release coating composition - Google Patents

Abstract

The present invention relates to organopolysiloxanes (A) having two or more alkenyl groups per molecule, organohydrogensiloxanes (B) having two or more silicon-bonded hydrogen atoms per molecule, and siloxane resins having silicon-bonded hydrogen groups A curable silicone release coating composition comprising (C), a platinum group metal catalyst (D), and optionally an inhibitor (E). The composition is useful as a release coating for pressure sensitive adhesives.

Description

Silicone release coating composition

The present invention provides a curable silicone release coating composition. More specifically, the present invention relates to curable silicone release coating compositions containing siloxane resin exfoliation modifiers having silicon-bonded hydrogen groups.

Silicone peel coatings coated and cured on various substrates often have very low peel strength. This low peel force is not always desirable because in many applications it is important to maintain a certain level of adhesion behavior or to provide different peel forces for several release liners. It is known that introducing an additive into the silicon bonded release coating increases the peel force required for the adhesive label to peel off. Such additives are referred to as controlled release additives or CRAs, and in some cases high performance release additives or HRAs. Such additives have also been described as peel modifiers or RMs.

Often materials include monovalent (M) siloxane group is used as the CRA [R ₃ SiO _1/2 group (wherein, R is a monovalent hydrocarbon group; and tetravalent (Q) siloxane groups containing only (SiO _4/2 groups) Siloxane resins, otherwise known as MQ resins, include similar silicone resins, silicone coating compositions and peel modifiers in the art, for example, US Pat. Nos. 3,627,851, 3,772,247, 4,340,709, 4,677,161 4,707,531, 4,855,381, 5,468,816, 5,468,816, 5,458,828 and 5,468,578.

However, the patent does not provide the industry with a solution to all requirements. There is a continuing need for improved CRAs that provide increased peel force. In particular, there is a need for a CRA that increases the peel force during a fast bilayer process.

The present invention relates to a curable silicone release coating composition comprising an alkenyl functional organopolysiloxane, an organohydrogensilicon compound, a platinum group metal catalyst, a siloxane resin having a silicon-bonded hydrogen group, and, optionally, an inhibitor.

The invention is further obtained by a process comprising mixing alkenyl functional organopolysiloxanes, organohydrogensilicon compounds, platinum group metal catalysts, siloxane resins with silicon-bonded hydrogen groups and, optionally, inhibitors. It relates to a curable silicone release coating composition that can be.

It is an object of the present invention to prepare effective controlled release additives for use in curable silicone release coating compositions.

Another object of the present invention is to use siloxane resins having silicon-bonded hydrogen groups as controlled release additives.

It is a further object of the present invention to prepare controlled release additives that have good efficacy over a wide range of concentrations.

The present invention relates to organopolysiloxanes (A) containing two or more alkenyl groups per molecule, linear organohydrogensiloxanes (B) having two or more silicon-bonded hydrogen atoms per molecule, molar ratios of M units to Q units A curable silicone release coating composition comprising a siloxane resin (C) of formula (I) having a value of 0.6 / 1 to 4/1 and a platinum group metal catalyst (D) is provided.

[Formula 1]

(R ₃ SiO _1/2 ) _a (HR ₂ SiO _1/2 ) _b (SiO _4/2 ) _c

In Chemical Formula 1,

R is a monovalent hydrocarbon group having 1 to 10 carbon atoms,

a is 1 to 25,

b is 2 to 10,

c is 1 to 50.

Alkenyl groups of component (A) include vinyl, allyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, 7-octenyl, 8-nonenyl, 9-decenyl, 10- Groups such as undecenyl, 4,7-octadienyl, 5,8-nonadienyl, 5,9-decadienyl, 6,11-dodecadienyl and 4,8-nonadienyl.

Preferably, component (A) is R ² ₃ SiO (R ¹ ₂ SiO) _x (R ¹ R ² SiO) _y SiR ² ₃ , R ² ₃ SiO (R ¹ ₂ SiO) _x SiR ² 3 and R ² ₃ Organopolysiloxanes selected from the group consisting of SiO (R ¹ R ² SiO) _y SiR ² ₃ , wherein R ¹ is independently selected from aliphatic unsaturated monovalent hydrocarbons or haloidlocarbon radicals of 1 to 10 carbon atoms, R ² is independently selected from the group consisting of R ¹ and alkenyl groups, x is greater than 0 and less than or equal to 7000, y is greater than 0 and less than or equal to 350, provided that there are at least two alkenyl groups per molecule) .

The monovalent radical R ¹ contains up to 10 carbon atoms and includes aliphatic unsaturated hydrocarbon or halohydrocarbon radicals. Aliphatic unsaturated monovalent hydrocarbon radicals include alkyl radicals (e.g. methyl, ethyl, propyl, butyl, hexyl, octyl and decyl), cycloaliphatic radicals (e.g. cyclohexyl), aryl radicals (e.g. phenyl, tolyl and xylyl ) And aralkyl radicals such as benzyl and phenylethyl. Very preferred monovalent hydrocarbon radicals for R ¹ are methyl and phenyl. Aliphatic unsaturated monovalent halohydrocarbon radicals include the monovalent hydrocarbon radicals described above in which one or more hydrogen atoms are replaced with halogen, such as fluorine, chlorine or bromine. The R ¹ radicals are preferably the same or different and it is preferred that at least 50% of all R ¹ radicals are methyl.

R ² is an alkenyl group preferably has the formula _{- (CH 2) d CH =} CH 2 or _{- (CH 2) e CH =} CH- (CH 2) f CH = CH 2 group (wherein a is 0 to d 20, e is 0 to 9, and f is 3, 4 or 5. U.S. Pat. No. 4,609,574 describes higher alkenyl functional organopolysiloxanes which are highly preferred for use herein.

Component (A) is ViMe ₂ SiO (Me ₂ SiO) _x SiMe ₂ Vi, Me ₃ SiO (Me ₂ SiO) _x (MeViSiO) _y SiMe ₃ , Me ₃ SiO (MeViSiO) _y SiMe ₃ , ViMe ₂ SiO (Me ₂ SiO) _x (MeViSiO) _y SiMe ₂ Vi, ViMe ₂ SiO (MeVSiO) _y SiMe ₂ Vi, HexMe ₂ SiO (MeViSiO) _x SiMe ₂ Hex, Me ₃ SiO (Me ₂ SiO) _x (MeHexSiO) _y SiMe ₃ , Me ₃ SiO (MeHexSiO) _y SiMe ₃ , HexMe ₂ SiO (Me ₂ SiO) _x (MeHexSiO) _y SiMe ₂ Hex and HexMe ₂ SiO (MeHexSiO) _y SiMe ₂ Hex where Me, Vi And Hex represent methyl, vinyl and 5-hexenyl, respectively, and the same thereafter), wherein x is greater than 0 and less than or equal to 7000 and y is greater than 0 and less than or equal to 350. Preferably, x is from 10 to 200 and y is from 1 to 10.

x and y are values at which the viscosity at 25 ° C of the organopolysiloxane component (A) is preferably at least 40 milliPascal-seconds (mPa · s) [1 mPa · s = 1 centipoise (cP)]. The viscosity of component (A) can be very high, similar to the raw rubber. If the viscosity is less than 40 mPa · s, it is difficult to coat the composition on the substrate. When the composition of the present invention does not contain a solvent, the viscosity at 25 ° C. of the component is preferably 40 to 10,000 mPa · s, more particularly 40 to 5,000 mPa · s. When the composition is in solution form, the viscosity range is the viscosity of 100,000 mPa · s to the raw rubber composition. However, when the composition is in solution form, the viscosity of component (A) preferably exceeds 500,000 mPa · s.

Organopolysiloxanes as component (A) are well known in the art, many of which are believed to be commercially available and need not be described further.

Component (B) is a linear organohydrogensiloxane having two or more silicon bonded hydrogen groups per molecule. Examples of component (B) include bis (trimethylsiloxy) dimethyldihydrogendisiloxane, heptamethylhydrogentrisiloxane, hexamethyldihydrogentrisiloxane, methylhydrogencyclosiloxane, pentamethylpentahydrogencyclopentasiloxane , Pentamethylhydrogendisiloxane, polymethylhydrogensiloxane, tetramethyltetrahydrogencyclotetrasiloxane, tetramethyldihydrogendisiloxane and methylhydrokensiloxane-dimethylsiloxane copolymer. U.S. Pat. No. 4,154,714 describes acceptable preferred organohydrogensiloxanes. The viscosity at 25 ° C. of component (B) is preferably 1 to 1,000 mPa · s, more preferably 5 to 500 mPa · s.

Component (B) is HMe ₂ SiO (Me ₂ SiO) _g (MeHSiO) _h SiMe ₂ H, HMe ₂ SiO (Me ₂ SiO) _g SiMe ₂ H, Me ₃ SiO (Me ₂ SiO) _g (MeHSiO) _h SiMe ₃ Is preferably a compound selected from the group consisting of HMe ₂ SiO (MeHSiO) _h SiMe ₂ H and Me ₃ SiO (MeHSiO) HSiMe ₃ , wherein g is greater than 0 and less than or equal to 1000 and h is greater than 0 and less than or equal to 200. .

Organohydrogensiloxanes as component (B) are well known in the art and many of these are commercially available and are believed to not need to be described further.

Component (C) is a siloxane resin of (R ₃ SiO _1/2 ) _a (HR ₂ SiO _1/2 ) _b (SiO _4/2 ) _c , wherein R is a monovalent hydrocarbon group having 1 to 10 carbon atoms, a Is a value from 1 to 25, b is a value from 2 to 10, c is from 1 to 50, and the molar ratio of M units to Q units is from 0.6 / 1 to 4/1, preferably from 1/1 to 3/1 , Most preferably 1/1 to 2/1). Monovalent hydrocarbon groups R include preferred embodiments and are as described above. It is preferred that R is methyl. It is preferable that a is 6-14, b is 3-5, and c is 4-15. It is especially preferable that b is three.

Such siloxane resins include, for example, aqueous hydrochloric acid and trialkyl containing alkyl silicates (partial hydrolysis condensates of alkaline orthosilicates or alkyl orthosilicates) as described in US Pat. No. 4,707,531. It is prepared by dropwise addition of silane or disiloxane or mixtures thereof with stirring at 0-90 ° C. or by use in a process in which the reactants are maintained at a constant rate during the process as described in US Pat. No. 5,391,673.

The SiH equivalent ratio of component (B) to component (C) is 1/99 to 99/1, preferably 10/90 to 90/10.

The sum total of component (B) and component (C) used for the composition of this invention is not restrict | limited. The sum of component (B) and component (C) expressed as the ratio of the number of silicon-bonded hydrogen source glasses of component (B) + (C) to the silicon-bonded alkenyl group of component (A) is 1/100 to It is an amount sufficient to provide a ratio of 100/1, preferably 1/2 to 20/1, most preferably 1/2 to 2/1 or more.

It is preferable to use 0.5-90 weight% of components (B) + (C) per 100 weight part of component (A), and it is very preferable that 2-20 weight part is used.

Component (D) is a platinum group metal catalyst that facilitates the reaction of silicon-bonded hydrogen atoms with silicon-bonded alkenyl groups. Here, the platinum group means ruthenium, rhodium, palladium, osmium, iridium and platinum.

The platinum group metal catalyst is preferably a platinum catalyst because platinum is the most widely used and commercially available and provides a more useful effect on the compositions of the present invention in terms of controlled shrinkage. The platinum catalyst may be a platinum group metal compound or a complex thereof. Preferred platinum catalysts include chloroplatinic acid, alcohol modified chloroplatinic acid, olefin complexes of chloroplatinic acid, complexes of chloroplatinic acid with divinyltetraethyldisiloxane, fine platinum particles absorbed on carbon carriers and platinum black.

Particularly preferred platinum catalysts in the compositions of the present invention are in the form of the chloroplatinic acid in the commercial hexahydrate form or in the form of anhydrides taught in US Pat. Another particularly useful catalyst is a compound that is readily dispersed in an organosilicon system, obtained by reacting chloroplatinic acid as described in US Pat. No. 3,419,593 with an aliphatic unsaturated organosilicon compound such as divinyltetramethyldisiloxane.

Platinum catalysts are well known in the art and many of these are commercially available and are believed to not need to be described further.

The amount of the platinum group metal catalyst used is not limited so long as it is sufficient to promote the room temperature reaction of the organohydrogensiloxane with the alkenyl organopolysiloxane and its action cannot be controlled by the use of an inhibitor. The required amount of the catalyst component depends on the specific catalyst used and cannot be easily predicted. However, in the case of the platinum catalyst, the amount of use is small, about 1 part by weight of platinum per million parts of component (A). However, preferably the catalyst is added in an amount of 10 to 10,000 parts by weight of platinum per million parts of component (A) and very preferably in an amount of 50 to 250 parts by weight of platinum per million parts of component (A).

The composition of the present invention optionally comprises an inhibitor (E). Inhibitors are any materials known or available to be used to inhibit the catalytic activity of platinum group metal catalysts. The term inhibitor herein does not interfere with elevated temperature cure of the curable mixtures of components (A), (B), (C) and (D) introduced in small amounts, for example less than 10 parts by weight of the composition and room temperature curing Means interfering substances. Examples of suitable inhibitors include ethylenic or aromatic unsaturated amides; An acetylene compound containing an acetylene alcohol and a silylated acetylene alcohol; Ethylenically unsaturated isocyanates, olefinic siloxanes, ball saturated hydrocarbon diesters, conjugated en-ynes, cyclic siloxanes, hydroperoxides, nitriles and diaziridine.

Preferred inhibitors include acetylene alcohols, unsaturated carboxylic acid esters such as diallyl maleate and dimethyl maleate, such as those described in US Pat. No. 3,445,420, including ethynylcyclohexanol and methylbutynol; Maleates and fumarates, such as those described in US Pat. Nos. 4,562,096 and 4,774,111, including diethyl fumarate, diallyl fumarate and bis (methoxyisopropyl) maleate; Conjugated en-ins, such as those described in US Pat. Nos. 4,465,818, 4,472,563, and 4,559,396, and ring siloxanes such as methylvinyltetracyclosiloxane or methylvinylpentacyclosiloxane. This patent conveniently teaches a method for preparing a compound suitable for use as an inhibitor in a composition of the present invention. Maleates, fumarates, acetylene alcohols, silylated acetylene alcohols, conjugated en-ynes and cyclic siloxanes are preferred as inhibitors in the compositions in the present invention.

The amount of inhibitor used in the release coating composition of the present invention is not critical. Preference is given to using from 0.1 to 10 parts by weight of inhibitor per 100 parts by weight of component (A).

The release coating composition of the present invention essentially comprises at least _one R ³ ₃ SiO _1/2 (M) unit and at least one SiO _4/2 (Q) unit, wherein R ³ is a monovalent hydrocarbon group having 1 to 10 carbon atoms. Or independently selected from the group consisting of alkenyl groups having 2 to 10 carbon atoms. The molar ratio of M units to Q units in the siloxane resin is 0.6 / 1 to 4/1, preferably 0.6 / 1 to 1.9 / 1, more preferably 1.2 / 1 to 1.6 / 1, most preferably 1.4 / 1. .

Group R ³ is a monovalent hydrocarbon group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms. Very preferred monovalent hydrocarbon groups as R ³ are methyl or phenyl and very preferred alkenyl groups are vinyl.

Examples of siloxane resins useful in the release coating composition of the present invention are siloxane resins consisting of Me ₃ SiO _1/2 (M) and SiO _4/2 (Q) units, Me ₂ ViSiO _1/2 (M) and SiO _4/2. Siloxane resin consisting of (Q) units and a siloxane resin consisting of Me ₃ SiO _1/2 (M), Me ₂ ViSiO _1/2 (M) and SiO _4/2 (Q) units, where Me is methyl and Vi Is vinyl and the molar ratio of M to Q is 0.6 / 1 to 1.9 / 1).

The siloxane resin is prepared by well known methods. It is preferably prepared by improved silica hydrosol capping as described in US Pat. No. 2,676,182 and in 3,627,851 and 3,772,247. The siloxane resin can also be prepared by cohydrolysis of trialkyl hydrolyzable silanes with alkyl silicates, as described in US Pat. No. 2,857,356.

Preferably 1 to 150 parts by weight, very preferably 5 to 80 parts by weight of siloxane resin is used per 100 parts by weight of component (A).

The release coating of the present invention may further contain an amount of bath life extender sufficient to further inhibit the room temperature curing reaction. Such extenders are further described in US Pat. No. 5,036,117. Examples of suitable bath life extenders include compounds containing one or more primary or secondary alcohol groups, carboxylic acids, including cyclic ethers and water, including compounds that provide carboxylic acids when exposed to water at room temperature. These include primary and secondary alcohols, diols and triols such as ethylene glycol, propylene glycol and glycerin, partial esters of diols and triols such as 2-methoxyethanol, 2-methoxypropanol and 2-methoxy Oxyisopropanol), tetrahydrofuran, water and aqueous solutions of inorganic acids, alkalis and salts. Preferably, primary and secondary alcohols having less than 10 carbon atoms are most preferred for the composition. Examples thereof include methanol, 1-butanol, 2-butanol, tetradecanol and other alkanols such as ethanol and n- and iso-propanol, iso-butanol and n-, secondary- and iso-pentanol, -hexane Ol, -heptanol and -octanol); Benzyl alcohol, phenol and other aromatic alcohols such as methylphenyl carbinol and 2-phenylethyl alcohol; Allyl alcohol and cyclohexanol. Very preferred bath life extenders are benzyl alcohol or water.

The amount of bath life extender used in the compositions of the present invention is not critical, but is an amount that provides a bath life that is longer than the bath life of the same composition containing no extender. The use amount of the bath life extender is 10 parts by weight, preferably 0.1 to 5 parts by weight, most preferably 1 to 3 parts by weight, per 100 parts by weight of component (A).

The release coating of the present invention may further comprise a diluent. Examples of suitable diluents include aliphatic hydrocarbons (such as pentane, hexane, heptane, octane and nonane), aromatic hydrocarbons (such as benzene, toluene and xylene), ketones (such as acetone, methyl ethyl ketone and methylisobutyl ketone) and substitutions Halogenated diluents such as trichloroethane, perchloroethylene and bromobenzene that are aliphatic or aromatic hydrocarbons. Two or more of these diluents may be used together.

The amount of diluent is not critical and can be readily determined by one skilled in the art. The composition of the present invention may contain up to 10,000 parts by weight of diluent, but is preferably used at 500 to 2,000 parts by weight per 100 parts by weight of component (A).

The release coatings of the present invention are suitable for mixing components (A), (B), (C), (D), optionally, (E) and any other components in any order (e.g. spatula, drum roller, mechanical A homogeneous mixing using a stirrer 3 roll mill, sigma blade mixer, extensive dough mixer and 2 roll mill). For storage stability, it is preferred to separate components (A) and (C) from components (B). This is achieved by mixing a portion of components (A), (C) and (D) as a first mixture, and then mixing component (B) and optional component (E) with the remaining amount of component (D) as a second mixture. do. Alternatively, the individual components may be stored and provided separately. Alternatively, component (A) and optional component (E) are provided as a first part, component (B) as a second part, and a mixture of component (C) and component (D) as a third part. Each of these parts may also comprise part of component (D) and any other components. Before the composition is used for the substrate, different parts and / or mixtures are mixed in the required proportions, for example 1/1, 10/1 or 100/1.

The release coatings of the present invention may also contain any components commonly used in platinum group metal catalyzed organosilicon compositions, such as reinforcing and extending fillers, aliphatic unsaturated hydrocarbons or halohydrocarbons, colorants, stabilizers, adhesion modifiers, α -An olefin and adhesive peel modifiers other than those mentioned above.

The compositions of the present invention are also useful as moldable compositions to provide organosilicon products such as zero rings, tubes, wire coatings, gaskets, encapsulants or sealants and are useful as coating compositions. The composition of the present invention is particularly useful as a peel coating.

In another aspect, the present invention provides a method of applying the curable silicone coating composition to a substrate surface (I) and exposing the coated surface to an energy source of heat (i) or actinic radiation (ii) in an amount sufficient to cure the coating. Provided is a coated substrate obtainable by a process comprising the step (II). The coated substrate of the invention can also be prepared by step (II) followed by step (III) of applying the adhesive to the coating. Curable silicone coating compositions to be used in the process are all of the compositions and optional ingredients described above, including amounts and preferred embodiments.

Actinic radiation means ultraviolet rays, electron beam irradiation, and alpha-, beta-, gamma-, and x-rays. Heat means those known in the art, such as infrared irradiation, hot air, microwave irradiation. Of course, actinic radiation is frequently used in combination with exposure to heat and it is suitable in this method to use a combination of both methods. In the preferred process of the present invention the coating step is known in the art such as spreading, brushing, extrusion, spraying, gravure, kiss-roll and air-knife. Use with any suitable method.

In a preferred embodiment the solid substrate is a flexible sheet material such as paper, polyolefin film and polyolefin coated paper or foil. Other suitable solid substrates covered by the method include other cellulosic materials (such as wood, cardboard and cotton), metallic materials (such as aluminum, copper, steel and silver), and siliceous materials (such as glass and stone). And synthetic polymeric materials such as polyolefins, polyamides, polyesters and polyacrylates. The solid substrate form may be substantially sheet-like or conformal, such as a release liner, fabric or foil for pressure sensitive adhesives.

The liquid curable composition is coated on a substrate and then heated and / or irradiated to cure the coating and adhere it to the substrate.

In a preferred embodiment, a flexible sheet material such as paper, metal foil or tapestock is coated with a thin layer of liquid curable composition, preferably in a continuous manner, and then the coated material is heated and / or irradiated to cure the coating quickly. The method provides a sheet-like material containing an adhesive release coating on one or more surfaces. The coating is then contacted with a pressure sensitive adhesive, preferably by an alignment method, to form a product having a peelable adhesive / coating interface. Examples of such products include adhesive labels in peelable backings, adhesive tapes in roll form, and adhesives packaged in loose containers. The pressure sensitive adhesive may also be a well known acrylic or rubbery non-silicone based or silicone based such as peroxide or platinum curable polyorganosiloxane based adhesive.

The method of the present invention is also applicable to adhesive materials other than pressure sensitive adhesives. Examples of such adhesive materials include food, asphalt and rubber polymers.

The following examples are intended to further teach, but not limit, the invention, which is suitably described by the appended claims. All amounts (parts and%) are by weight unless otherwise indicated. Viscosity is measured using a rotating mandrel viscometer at 25 ° C. [1 centistoke (cS) = 1 mm ² / s]. In the examples Me represents methyl, Vi represents vinyl and Hex represents 5-hexenyl.

In the examples the compositions are prepared using the following materials:

Organopolysiloxane A is a compound having a degree of polymerization (Dp) of the formula HexMe ₂ SiO (Me ₂ SiO) _a SiMe ₂ Hex of 30.

Organopolysiloxane B is a compound containing 2 mol% of hexenyl groups of the formula HexMe ₂ SiO (Me ₂ SiO) _x (MeHexSiO) _y SiMe ₂ Hex and having a degree of polymerization (Dp) of 150.

Organohydrogensiloxane A is a trimethylsilylsiloxy blocked polydimethylsiloxane-methylhydrogensiloxane copolymer having a Dp of 40 and containing 70 mol% of methylhydrogen residues in the siloxane chain.

Catalyst A is a platinum catalyst which is a soluble platinum complex containing 0.50% platinum formed from chloroplatinic acid and divinyltetramethyldisiloxane.

Inhibitor A is bis (2-methoxy-1-methylethyl) maleate.

The siloxane resin A is essentially a benzene-soluble siloxane resin copolymer consisting of Me ₃ SiO _1/2 (M), Me ₂ ViSiO _1/2 (Q) and SiO ₂ units, wherein the molar ratio of M units to Q units is 0.7 / 1 and the siloxane resin copolymer contains 1.75 to 2.3% by weight of vinyl).

The siloxane resin B has three silicon-bonded hydrogen atoms per molecule and has a viscosity of 35 cS and a SiH of 0.3 wt% (Me ₃ SiO _1/2 ) _a (HMe ₂ SiO _1/2 ) _b (SiO _4/2 ) _c is a compound wherein a is 5, b is 3 and c is 4.

Example 1

A peel modifier is prepared by mixing 50 parts of siloxane resin A and 50 parts of organopolysiloxane A. This peel modifier is referred to as RM 1 (peel modifier 1). 97.3 parts of organopolysiloxane B, 1.9 parts of catalyst A and 0.8 parts of inhibitor A are added to a 118.3 ml (4 oz) container, and the mixture is stirred to prepare a coating. This is referred to as coating A. Subsequently, a predetermined amount of coating A, RM 1, siloxane resin B (SRB) and organohydrogensiloxane A (OHSA) are mixed with a rotary mixer for 10 minutes to prepare a peel coating composition. The SiH equivalent ratio of SRB to OHSA is shown in Table 1. The components are mixed in the amount (g) shown in Table 1. Thereby, nine types of silicone peeling coating compositions are manufactured (represented by REL 1 to REL 9 in Table 1).

The resulting nine types of silicone release coating compositions were coated on S2S kraft paper at a thickness of 317.8 g / ream (0.71 lb / ream) using a handroll blade coater. The coated paper is cured for 15 seconds in a forced air oven at 300 ° C., a pilot coater. A plastic film coated with a commercially available hot melt pressure sensitive adhesive was laminated again using a 2.3 kg (5 lb) hard rubber coated roller on a newly prepared peel coating surface. The coatings are age hardened at room temperature for 1 day and then laminated. The laminate is also further age hardened for one day at room temperature under pressure. The laminate is cut into strips of 25.4 mm (1 inch) in width for peel force measurements. The peel test is carried out using an Imass ^R high speed peel tester at five different two-layer speeds: 0.3 m / min, 1 m / min, 10 m / min, 100 m / min and 300 m / min. The peel force measured four times at each speed was averaged and the average value obtained is shown in Table 2 for each sample. Table 2 shows the peel force in g / 2.54 cm.

TABLE 1

TABLE 2

The curable silicone release coating composition of the present invention is effective as a release coating for pressure sensitive adhesives.

Claims (7)

Organopolysiloxanes (A) containing two or more alkenyl groups per molecule, linear organohydrogensiloxanes (B) having two or more silicon-bonded hydrogen atoms per molecule, with a molar ratio of M units to Q units of 0.6 / A curable silicone release coating composition comprising a siloxane resin (C) of formula (1) being from 1 to 4/1 and a platinum group metal catalyst (D). [Formula 1] (R ₃ SiO _1/2 ) _a (HR ₂ SiO _1/2 ) _b (SiO _4/2 ) _c In Chemical Formula 1, R is a monovalent hydrocarbon group having 1 to 10 carbon atoms, a is 1 to 25, b is 2 to 10, c is 1 to 50. The composition of claim 1 further comprising an inhibitor (E). The compound of claim 1, wherein at least _one R ³ ₃ SiO _1/2 (M) unit and at least one SiO _4/2 (Q) unit, wherein R ³ is a monovalent hydrocarbon group having 1 to 10 carbon atoms or Independently selected from the group consisting of alkenyl groups of 2 to 10 carbon atoms, and the molar ratio of M units to Q units is selected from the group consisting of siloxane resins, bath life extenders and diluents of 0.4 / 1 to 4/1. A composition comprising at least one component further. Organopolysiloxanes (A) containing two or more alkenyl groups per molecule, linear organohydrogensiloxanes (B) having two or more silicon-bonded hydrogen atoms per molecule, molar ratios of M units to Q units [where M represents monovalent (R ₃ SiO _1/2 ) _a unit and (HR ₂ SiO _1/2 ) _b unit, and Q represents tetravalent (SiO _4/2 ) _c unit] is 0.6 / 1 to 4 / A curable silicone release coating composition obtainable by a process comprising the step (I) of mixing a siloxane resin (C) of formula (1) and a platinum group metal catalyst (D) of formula (1). [Formula 1] (R ₃ SiO _1/2 ) _a (HR ₂ SiO _1/2 ) _b (SiO _4/2 ) _c In Chemical Formula 1, R is a monovalent hydrocarbon group having 1 to 10 carbon atoms, a is 1 to 25, b is 2 to 10, c is 1 to 50. A coated substrate obtainable by a method comprising applying the curable resin composition of claim 1 to a substrate surface. 6. The coated substrate of claim 5, wherein the method further comprises the step (II) of exposing the coating and the substrate to an amount of heat and actinic radiation sufficient to cure the coating. 6. The coated substrate of claim 5, wherein the method further comprises applying a pressure sensitive adhesive to the coated substrate after step (II).