Silicone release coating containing alkenyl-functional tristrimethylsiloxy silicone

Abstract

A curable silicone release coating composition comprises: (a) an alkenyl-functionalized silicone adhesive having an average of at least 2 alkenyl groups per molecule; (b) a SiH-functionalized silicone having an average of at least 2 SiH groups per molecule, the concentration of which is such that the molar ratio of SiH groups to alkenyl groups from the alkenyl-functionalized silicone adhesive is greater than 1.00; (c) an alkenyl-functionalized siloxane release additive having an average chemical formula of [(CH3)3SiO]3SiR, wherein R is a terminal unsaturated hydrocarbon group containing 2 to 20 carbon atoms; (d) a hydrogenation silanization catalyst; and (e) optionally, any combination of one or more components selected from: a solvent, an additional release agent, a hydrogenation silanization inhibitor, an adhesion promoter, pyrolytic silica, and MQ resin.

Description

Technical Field

[0001] This invention relates to silicone stripping coating compositions containing alkenyl-functionalized tris(trimethylsiloxy)siloxane. Background Technology

[0002] Silicone release coatings have become a popular choice in industry due to their low surface energy. Silicone release coatings are typically formed by crosslinking (curing) a curable silicone release composition. The continued development of higher-quality adhesion, such as in optically clear adhesives (OCAs) and multilayer ceramic capacitors (MLCCs), continues to drive the need for release coatings with lower peel strength, even in silicone release coatings, to increase productivity with faster peeling speeds without compromising the quality of the adhesive.

[0003] Current methods for reducing the peel strength of release coatings include increasing the surface roughness of the coating by incorporating silica particles and adding monofunctional polymers to control the modulus of the release coating composition. These methods tend to disadvantageously increase cost efficiency and reduce product quality stability.

[0004] The field will advance the search for a new way to reduce the peel force of silicone release coatings. Summary of the Invention

[0005] This invention provides a solution to the challenge of determining a new way to reduce the peel strength of silicone release coatings. The invention is based on the discovery that including a tris(trimethylsiloxy)siloxane having the chemical formula [(CH3)3SiO]3SiR (where R is a terminal unsaturated hydrocarbon group) in a curable silicone release coating formulation reduces the peel strength of the resulting release coating.

[0006] In a first aspect, the present invention is a curable silicone release coating composition comprising: (a) an alkenyl-functionalized silicone resin having an average of at least two alkenyl groups per molecule; and (b) a SiH-functionalized silicone having an average of at least two SiH groups per molecule, the concentration of which is such that the SiH groups are relatively concentrated relative to the alkenyl-functionalized silicone resin. (c) The molar ratio of alkenyl groups of gum is greater than 1.00; (d) Alkenyl-functionalized siloxane stripping additive having an average chemical formula of [(CH3)3SiO]3SiR, wherein R is a terminal unsaturated hydrocarbon group containing 2 to 20 carbon atoms; (e) Hydrosilylation catalyst; and (f) Optionally, any combination of one or more components selected from the following: solvent, additional stripping agent, hydrosilylation inhibitor, adhesion promoter, pyrolytic silica and MQ resin.

[0007] In a second aspect, the present invention is a method of using the curable silicone release coating composition of the first aspect, wherein the method comprises applying a coating of the curable silicone release coating composition to a substrate and then heating the coating to cure the curable silicone release coating composition.

[0008] This invention can be used to prepare silicone release coatings. Detailed Implementation

[0009] When a date is not indicated by a test method number, the test method refers to the most recent test method as of the priority date of this document. References to test methods include references to both the testing association and the test method number. The following test method abbreviations and designations apply to this document: ASTM refers to ASTM International Society Methods; END refers to European Standards; DIN refers to the German Institute for Standardization; ISO refers to the International Organization for Standardization; and UL refers to Underwriters Laboratories.

[0010] Products identified by their trade names refer to compositions available under those trade names as of the priority date of this document.

[0011] "Multiple" means two or more. "And / or" means "and, or as an alternative." Unless otherwise specified, all ranges include the endpoints.

[0012] When referring to values ​​describing molecules, "average" means the average value of a sample of molecules, because it is usually difficult to measure the value of a single molecule.

[0013] This invention relates to a curable silicone release coating composition. "Cureable" means that the composition is capable of chemical crosslinking. In this case, the composition can undergo crosslinking via hydrosilanization. A "release coating composition" is a composition that can be applied as a coating to a substrate and cured to form a release coating, which is a coating that can be applied with another component and can also be removed again.

[0014] The curable silicone release coating composition of the present invention comprises: (a) an alkenyl-functionalized silicone adhesive having an average of at least two alkenyl groups per molecule; (b) a SiH-functionalized silicone having an average of at least two silyl hydride (SiH) groups per molecule; (c) an alkenyl-functionalized siloxane release additive; (d) a hydrogenation silanization catalyst; and optionally (e) one or any combination of more than one component selected from the following: hydrogenation silanization inhibitors, adhesion promoters, pyrolytic silica, and MQ resin.

[0015] (a) Alkenyl-functionalized silicone adhesive

[0016] The alkenyl-functionalized silicone compound component contains an average of at least two alkenyl groups per molecule. The alkenyl groups are preferably terminally unsaturated. Preferably, the alkenyl groups contain two or more, and may contain three or more, four or more, five or more, six or more, or even seven or more carbon atoms, while typically containing eight or fewer, and may contain seven or fewer, six or fewer, five or fewer, four or fewer, or even three or fewer carbon atoms. Typically, the alkenyl groups are selected from vinyl and allyl groups. The alkenyl-functionalized silicone compound may be free of SiH groups.

[0017] Alkenyl-functionalized silicone compounds are preferably a linear alkenyl-functionalized silicone polymer or any combination of more than one linear alkenyl-functionalized silicone polymer. For example, an alkenyl-functionalized silicone compound can be any silicone compound having an average chemical formula (I) or any combination of more than one silicone compound:

[0018]

[0019] in:

[0020] The subscripts x and y are each selected from zero or one, provided that one or both of the subscripts x and y are zero.

[0021] R' is a hydrocarbon group having 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, or even 7 or more, while having 8 or fewer, 7 or fewer, 6 or fewer, 5 or fewer, 4 or fewer, or even 3 or fewer carbon atoms;

[0022] The subscript m has an average value in the range of 20 to 10,000, and can be 20 or greater, 40 or greater, 50 or greater, 100 or greater, 250 or greater, 500 or greater, 750 or greater, 1000 or greater, 2000 or greater, 3000 or greater, 4000 or greater, 5000 or greater, 6000 or greater, or even 70000 or greater, while typically being 10,000 or less, 9000 or less, 8000 or less, 8000 or less, 6000 or less, 5000 or less, 1000 or less, 750 or less, or even 500 or less;

[0023] The subscript n has an average value in the range of 20 to 1000, and can be 20 or greater, 30 or greater, 40 or greater, 50 or greater, 60 or greater, 70 or greater, 80 or greater, 90 or greater, 100 or greater, 120 or greater, 140 or greater, 160 or greater, 180 or greater, 200 or greater, 250 or greater, 300 or greater, 400 or greater, 500 or greater, 600 or greater, 700 or greater, 800 or greater, 900 or greater, while typically being 1000 or less, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 300 or less, 250 or less, 200 or less, 170 or less, 150 or less, 130 or less, 110 or less, 100 or less, and can be 90 or less; and

[0024] X is independently selected from the group consisting of R' and perfluoroalkyl groups each time it appears; examples of suitable X groups include vinyl groups, hexenyl groups and perfluoroalkyl groups, such as perfluorobutylethyl (“PFBE”) groups (CF3CF2CF2CF2CH2CH2-).

[0025] (b) SiH-functionalized silicone

[0026] SiH-functionalized silicones have an average of at least two SiH groups per molecule. SiH-functionalized silicones may not contain alkenyl groups, or even be completely free of unsaturated groups.

[0027] SiH-functionalized silicones can be a single linear SiH-functionalized silicone or any combination of more than one linear SiH-functionalized silicone. For example, a SiH-functionalized silicone can be any SiH-functionalized silicone or any combination of more than one selected from those having the following average chemical structures:

[0028]

[0029] as well as

[0030]

[0031] in:

[0032] The subscript d has a value in the range of 0 to 50, and can be 0 or greater, 2 or greater, 4 or greater, 8 or greater, 10 or greater, 15 or greater, 20 or greater, 25 or greater, 30 or greater, 35 or greater, 40 or greater, or even 45 or greater, while typically it is 50 or less, and can be 40 or less, 30 or less, 20 or less, or even 10 or less;

[0033] The subscript d' has a value in the range of 10 to 50, and can be 10 or greater, 15 or greater, 20 or greater, 25 or greater, 30 or greater, 35 or greater, 40 or greater, or even 45 or greater, while typically it is 50 or less, and can be 40 or less, 30 or less, 20 or less, or even 10 or less.

[0034] The subscript d'' has a value in the range of 0 to 20, and can be 0 or greater, 2 or greater, 4 or greater, 8 or greater, 10 or greater, or even 15 or greater, while typically being 20 or less, 18 or less, 16 or less, 14 or less, 12 or less, 10 or less, 8 or less, 6 or less, 4 or less, or even 2 or less; and

[0035] PFA refers to a perfluoroalkyl group, preferably a perfluorobutylethyl ("PFBE") group (CF3CF2CF2CF2CH2CH2-).

[0036] The concentration of SiH-functionalized silicone in the curable silicone release coating composition is preferably sufficient to provide a molar ratio of SiH groups to olefin groups from the olefin-functionalized silicone compound, which is greater than 1.00 and can be 1.10 or greater, 1.20 or greater, or even 1.30 or greater, while typically 2.00 or less, and can be 1.90 or less, 1.80 or less, 1.70 or less, 1.60 or less, 1.50 or less, or even 1.40 or less.

[0037] (c) Alkenyl-functionalized siloxane stripping additive

[0038] Alkenyl-functionalized siloxane stripping additives have the following average chemical formula:

[0039]

[0040] Wherein R is a terminal unsaturated hydrocarbon group containing two or more carbon atoms, and may contain 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 12 or more, 14 or more, 16 or more, or even 18 or more carbon atoms, while typically containing 20 or fewer, 18 or fewer, 16 or fewer, 14 or fewer, 12 or fewer, 10 or fewer, 8 or fewer, 6 or fewer, 4 or fewer, or even 2 or fewer carbon atoms. R may be selected, for example, from vinyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, or even octenyl.

[0041] The concentration of alkenyl-functionalized siloxane release additives is typically in the range of greater than 0% (wt%) to 3% (wt%) of the curable silicone release coating composition. Based on the weight of the curable silicone release coating composition, the concentration of alkenyl-functionalized siloxane release additives can be 0.1% (wt%) or higher, 0.2% (wt%) or higher, 0.3% (wt%) or higher, 0.4% (wt%) or higher, 0.5% (wt%) or higher, 0.6% (wt%) or higher, 0.7% (wt%) or higher, 0.8% (wt%) or higher, 0.9% (wt%) or higher, 1.0% (wt%) or higher, 1.2% (wt%) or higher, 1.4% (wt%) or higher, 1.6% (wt%) or higher, 1.8% (wt%) or higher, or even 2.0% (wt%) or higher. Typically 10% by weight or less, but can be 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2.8% by weight or less, 2.6% by weight or less, 2.4% by weight or less, 2.2% by weight or less, 2.0% by weight or less, 1.8% by weight or less, 1.6% by weight or less, 1.4% by weight or less, 1.2% by weight or less, 1.0% by weight or less, or even 0.8% by weight or less.

[0042] Alkenyl-functionalized siloxane stripping additives may have, for example, the following chemical formula: [(CH3)3SiO]3(Hex)Si, where "Hex" refers to a hexenyl group having a terminal carbon-carbon double bond (C=C).

[0043] (d) Hydrogenation silanization catalyst

[0044] The hydrosilylation catalyst (d) can be any hydrosilylation catalyst known in the art. For example, the hydrosilylation catalyst can be selected from the group consisting of: (d-1) metals selected from platinum, rhodium, ruthenium, palladium, osmium and iridium; (d-2) compounds of metal (d-1); (d-3) complexes of compound (d-2) with organopolysiloxanes; and (d-4) compounds (d-2) microencapsulated in a matrix or core / shell structure. Examples of suitable hydrosilylation catalysts are: (d-1) metals selected from platinum, rhodium, ruthenium, palladium, osmium, and iridium; (d-2) compounds of such (d-1) metals, such as tris(triphenylphosphine)rhodium(I) chloride (Wilkinson's Catalyst), rhodium diphosphine chelates such as [1,2-bis(diphenylphosphine)ethane]dichlorodirhodium or [1,2-bis(diethylphosphine)ethane]dichlorodirhodium, chloroplatinic acid (Speier catalyst), chloroplatinic acid hexahydrate, and platinum dichloride; (d-3) complexes of the compounds described above (d-2) with organopolysiloxanes or platinum compounds microencapsulated in a matrix or core / shell structure. Platinum complexes with organopolysiloxanes include complexes of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane with platinum (Karstedt catalyst); and (d-4) compounds or complexes described above microencapsulated in a resin matrix.

[0045] The concentration of the hydrogen silanization catalyst is sufficient to catalyze the curing reaction of the curable silicone release coating. Typically, the concentration of the hydrogen silanization catalyst is from 1 part by mass to 500 parts by mass, and can be 1 part by mass or more, 5 parts by mass or more, 10 parts by mass or more, or even 20 parts by mass or more, while typically 500 parts by mass or less, and can be 300 parts by mass or less, or even 100 parts by mass or less, wherein the parts by mass are relative to a combination of 1 million parts by mass of alkenyl-functionalized silicone material (a) and SiH-functionalized silicone (b).

[0046] (e) Optional components

[0047] Curable silicone release coating compositions may contain or exclude any one or any combination of additional optional components. For example, a curable silicone release coating composition may contain any one or any combination of more than one component selected from: solvent, additional release agent, hydrogenated silanization inhibitor, adhesion promoter, pyrolytic silica, and MQ resin.

[0048] Examples of suitable hydrosilylation inhibitors include those selected from the group consisting of: alkynols; silylalkynes; cycloalkenylsiloxanes; en-alkynyl compounds; triazoles; phosphines; thiols; hydrazides; amines; fumarates, such as dialkyl fumarate, dienyl fumarate, and dialkoxyalkyl fumarate; maleate esters, nitriles, ethers, and combinations of two or more of the above substances. Suitable alkynols include dimethylhexynol and 3,5-dimethyl-1-hexyn-3-ol, methylbutynols such as 1-butyn-3-ol, 1-propyn-3-ol, 2-methyl-3-butyn-2-ol, 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3-phenyl-1-butyn-3-ol, 4-ethyl-1-octyyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol and 1-ethynyl-1-cyclohexanol, and combinations thereof. Suitable cycloalkenylsiloxanes include methylvinylcyclotetrasiloxanes exemplified by 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, and combinations thereof. Suitable enyne compounds include 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne. Suitable triazoles include benzotriazoles. Suitable amines include tetramethylethylenediamine. Silylated alkynes include (3-methyl-1-butyn-3-oxy)trimethylsilane, ((1,1-dimethyl-2-propynyl)oxy)trimethylsilane, bis(3-methyl-1-butyn-3-oxy)dimethylsilane, bis(3-methyl-1-butyn-3-oxy)silanemethylvinylsilane, bis((1,1-dimethyl-2-propynyl)oxy)dimethylsilane, methyl(tris(1,1-dimethyl-2-propynyloxy))silane, methyl(tris(3-methyl-1-butyn-3-oxy))silane, (3-methyl-1-butyn-3-oxy)dimethylphenylsilane, (3-methyl-1-butyn-3-oxy)dimethylhexenylsilane, (3-methyl-1-butyn-3-oxy)dimethylhexenylsilane, (3-methyl-1-butynyl)silane, and (3-methyl-1-butynyl)silane. (3-O-yne-triethylsilane), bis(3-methyl-1-butyn-3-oxy)methyltrifluoropropylsilane, (3,5-dimethyl-1-hexyn-3-oxy)trimethylsilane, (3-phenyl-1-butyn-3-oxy)diphenylmethylsilane, (3-phenyl-1-butyn-3-oxy)dimethylphenyldimethylvinylsilane, (3-phenyl-1-butyn-3-oxy)dimethylhexenylsilane, (cyclohexyl-1-ethyn-1-oxy)dimethylhexenylsilane, (cyclohexyl-1-ethyn-1-oxy)dimethylvinylsilane, (cyclohexyl-1-ethyn-1-oxy)diphenylmethylsilane, (cyclohexyl-1-ethyn-1-oxy)trimethylsilane, and combinations thereof.

[0049] Based on the weight of the curable silicone release coating composition, the amount of inhibitor is 0% by weight (wt%) or greater, and can be 0.001% by weight or greater, 0.0025% by weight or greater, or even 0.01% by weight or greater, while typically 5% by weight or less, and can be 1% by weight or less, 0.5% by weight or less, or even 0.025% by weight or less.

[0050] Suitable adhesion promoters include reaction products of vinylalkoxysilanes and epoxy-functionalized alkoxysilanes; reaction products of vinylacetoxysilanes and epoxy-functionalized alkoxysilanes; and combinations of polyorganosiloxanes having at least one aliphatic unsaturated hydrocarbon group and at least one hydrolyzable group per molecule with epoxy-functionalized alkoxysilanes (e.g., physical blends and / or reaction products) (e.g., combinations of hydroxyl-terminated vinyl-functionalized polydimethylsiloxanes and glycidoxypropyltrimethoxysilane). Based on the weight of the curable silicone release coating composition, the suitable concentration of the adhesion promoter is typically 0% by weight or more, and can be 0.01% by weight or more, 0.1% by weight or more, 0.2% by weight or more, 0.3% by weight or more, 0.4% by weight or more, or even 0.5% by weight or more, while typically 2% by weight or less, and can be 1% by weight or less, 0.9% by weight or less, 0.8% by weight or less, 0.7% by weight or less, or even 0.6% by weight or less.

[0051] MQ resin refers to SiO 4 / 2 Siloxane units and R'3SiO 1 / 2 Silicone resins with siloxane units, wherein R' is as defined above.

[0052] The present invention also includes a method for using the curable silicone release coating composition of the present invention, wherein the method comprises applying a coating of the curable silicone release coating composition to a substrate and then heating the coating to cure the curable silicone release coating composition. Typically, the coating is applied at temperatures below 100 degrees Celsius (°C), more typically at 80°C or lower, 70°C or lower, 60°C or lower, 50°C or lower, 40°C or lower, or even 30°C or lower, while simultaneously at temperatures above 0°C, typically 10°C or higher, 20°C or higher, or even 25°C or higher. The coating is typically cured at temperatures of 120°C or higher, even 130°C or higher, 140°C or higher, 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, while simultaneously at 250°C or lower, preferably 200°C or lower, even 190°C or lower, or at 180°C or lower.

[0053] Example

[0054] Table 1 lists the materials used in the following samples. “Hex” refers to a hexenyl group. “Me” refers to a methyl group. “Vi” refers to a vinyl group. “PFBE” refers to a perfluorobutylethyl group (CF3CF2CF2CF2CH2CH2-). DOWSIL is a trademark of Dow Chemical Company. SYL-OFF is a trademark of Dow Silicones Corporation. “TDCC” refers to Dow Chemical Company.

[0055]

[0056] Preparation of alkenyl-functionalized exfoliating additive (c)-1

[0057] 92.67 g of hexamethyldisiloxane (SigmaAldrich), 10.97 g of deionized water, and 0.18 g of trifluoromethanesulfonic acid (SigmaAldrich) were mixed and then stirred at 23°C for 10 minutes. 100 g of 5-hexenyltrimethoxysilane (Gelest) was added and stirred at 23°C for 30 minutes. Methanol was removed under vacuum (18 kPa pressure) at 25°C to 50°C for 6 hours. Ammonia was added for neutralization and stirred for 10 minutes. Volatile matter was removed under vacuum (1.3 kPa pressure) for 1 hour. The mixture was filtered through a 0.2 μm PTFE filter to remove salt, thus obtaining the isolated alkenyl-functionalized stripping additive (c)-1.

[0058] Sample preparation

[0059] Prepare the following samples according to the formulations in the table below, which shows the weight percentage of each component (except the catalyst). Mix the components in a container at the specified ratio. Shake or mix the mixed components together to form a mixture that is as homogeneous as possible. Add the hydrogenation silylation catalyst to the homogeneous mixture to provide 100 parts by weight of platinum per million parts by weight of sample, and mix to form the sample composition.

[0060] The sample composition was coated onto the substrate.

[0061] The sample composition was coated onto a polyethylene terephthalate (PET) film using a Euclid coater. The coating weight was measured in paper mode using an Oxford Instruments Lab-X 3500 benchtop XRF analyzer or a Rigaku NEX QC+ XRF analyzer. The coating was cured by passing the coated substrate through an oven at 182°C (360°F) for 8 to 12 seconds.

[0062] Measure the peel force of the cured sample coating

[0063] Three Tesa ™ 7475 tape (Tesa is a trademark of Tesa SE Corporation) was laminated onto sheets of cured samples coated on PET film. The tape was pressed onto the cured sample film using a 1.36 kg (3 lb) roller three times. One set of samples was left to stand at 25°C for 24 hours at 1 kg weight, and another set was left to stand at 60°C for 24 hours at the same weight to test for load aging at both temperatures. The strips were cut into 2.54 cm (1 inch) strips. The peel force of each strip was measured using a TMI adhesive strength tester, in grams per inch (gf / inch), while the tape was pulled from the coating at a rate of 762 cm (300 inch) / min at a 180° angle. The average of the three strips was reported as the sample peel force (initial peel force).

[0064] Secondary adhesion strength (SAS)

[0065] After measuring the peel force on the sample, by using three new Tesa ™ 7475 tape was pressed onto a cured sample coated on PET, and the peel force was measured repeatedly on the same sample, with the tape removed from the PET during the initial peel force measurement. The peel force (second peel force) was measured when a second tape was removed in a similar manner. The secondary adhesive strength (SAS) was calculated as a percentage using the following method: [(initial peel force) - (second peel force) / initial peel force] × 100%.

[0066] The desired SAS value is as close to 100% as possible. A lower SAS value indicates a greater change in the peeling ability of the peeling coating after a material is removed from it. This suggests that removing the material from the peeling coating alters it in some way, undesirably making it more viscous.

[0067] Samples A to C: Evaluation of stripping agent 2

[0068] Table 2 presents the formulation of each component of samples A through C by weight (%) and their peel strength results after aging at 25°C and 60°C. Sample A is a reference without the release agent, while samples B and C include release agent 2. The data in Table 2 reveal that the addition of release agent 2 actually increases the peel force associated with the cured sample coating. This is the opposite of the expected result.

[0069]

[0070] Samples D and 1 through 9: Evaluation of alkenyl-functionalized siloxane stripping additives

[0071] Table 3 presents the formulations of each component of samples D and 1 through 9 by weight, along with their peel strength results after aging at 25°C and 60°C. Sample D is a reference without the peeling agent, while samples 1 through 9 contain alkenyl-functionalized siloxane peeling additive (c)-1. The percentage change in peel force relative to sample D is expressed as peel force.

[0072] The data in Table 3 show that the addition of alkenyl-functionalized siloxane peeling additives significantly reduced the peel force associated with the cured sample coatings at storage temperatures of 25°C and 60°C.

[0073]

[0074] Samples E and 10 to 13: Evaluation of alkenyl-functionalized siloxane release additives and different alkenyl-functionalized silicone sealants material

[0075] Table 4 presents the formulations of each component of samples E and 10 to 13 by weight, along with their peel strength results after aging at 25°C and 60°C. Sample E is a reference without the peeling agent, while samples 10 to 13 contain alkenyl-functionalized siloxane peeling additive (c)-1. The percentage change in peel force relative to sample D is expressed as peel force.

[0076] The data in Table 4 show that the addition of alkenyl-functionalized siloxane stripping additives reduced the peel force associated with the cured sample coating at storage temperatures of 25°C and 60°C.

[0077]

[0078] Samples F to J and 14 to 16: Comparison with fluorinated stripping agents

[0079] Fluorinated stripping agents are commonly available on the market. These samples compare the performance of fluorinated stripping agents with that of the alkenyl-functionalized siloxane stripping agent of the present invention.

[0080] Table 5 presents the formulations of each component of samples F to J and 14 to 16 by weight, along with their peel strength results after aging at 25°C and 60°C. Samples F, H, and J are references without peeling agent. Samples G and I contain a fluorinated peeling agent (peeling agent 1). Samples 14 to 16 include an alkenyl-functionalized siloxane peeling additive (c)-1. The percentage change in peel force relative to sample D is expressed as peel force.

[0081] Compared to the corresponding reference sample, the fluorinated stripper undesirably reduced the SAS (Self-Rating Scale). Alkenyl-functionalized siloxane stripper additives outperformed the fluorinated stripper in reducing stripping force without significantly reducing SAS.

[0082]

Claims

1. A curable silicone release coating composition, said curable silicone release coating composition comprising: (a) Alkenyl-functionalized silicone compound having an average of at least 2 alkenyl groups per molecule; (b) A SiH-functionalized silicone having an average of at least 2 SiH groups per molecule, wherein the concentration of the SiH-functionalized silicone is such that the molar ratio of SiH groups to alkenyl groups from the alkenyl-functionalized silicone compound is greater than 1.

00. (c) An alkenyl-functionalized siloxane stripping additive having an average chemical formula of [(CH3)3SiO]3SiR, wherein R is a terminal unsaturated hydrocarbon group containing 2 to 20 carbon atoms, relative to the curable silicone stripping coating composition. (d) Hydrosilylation catalyst; and (e) Optionally, a component or any combination of one or more of the following: solvent, additional stripping agent, hydrogenated silanization inhibitor, adhesion promoter, pyrolytic silica and MQ resin.

2. The curable silicone release coating composition according to claim 1, wherein the alkenyl-functionalized silicone adhesive is a linear alkenyl-functionalized silicone polymer or any combination of more than one linear alkenyl-functionalized silicone polymer.

3. The curable silicone release coating composition according to claim 1, wherein the alkenyl-functionalized silicone compound is a linear silicone or any combination of more than one linear silicone, the linear silicone being selected from the group consisting of silicone compounds having the following average chemical formulas: in: The subscripts x and y are each zero or one, provided that at least one of the subscripts x and y is zero. R' is a hydrocarbon group having 2 to 8 carbon atoms with a terminal alkenyl group; The subscript m has an average value in the range of 20 to 10,000; The subscript n has an average value in the range of 20 to 1000; and X is independently selected from the group consisting of R' and PFA each time it appears, where PFA refers to a perfluoroalkyl group.

4. The curable silicone release coating composition according to any of the preceding claims, wherein the SiH-functionalized silicone is any linear SiH-functionalized silicone polymer or any combination of more linear SiH-functionalized silicone polymers.

5. The curable silicone release coating composition according to claim 4, wherein the SiH-functionalized silicone is any one type of SiH-functionalized silicone or any combination of more than one type of SiH-functionalized silicone, wherein the SiH-functionalized silicone is selected from those having the following average chemical formula: as well as in: The subscript d has a value in the range of 0 to 50; The subscript d' has a value in the range of 10 to 50; The subscript d'' has a value in the range of 0 to 20; and PFA stands for perfluoroalkyl group.

6. The curable silicone stripping coating composition according to any of the preceding claims, wherein the alkenyl-functionalized siloxane stripping additive has the following average chemical composition: [(CH3)3SiO]3(Hex)Si, wherein Hex refers to a hexenyl group having a terminal C=C bond.

7. The curable silicone stripping coating composition according to any of the preceding claims, wherein the curable silicone stripping coating composition comprises a hydrogenated silanization inhibitor.

8. A method of using a curable silicone release coating composition according to any of the preceding claims, wherein the method comprises applying a coating of the curable silicone release coating composition onto a substrate, and then heating the coating to cure the curable silicone release coating composition.

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