COATING COMPOSITION AND ITS USES

Abstract

The present disclosure relates to a leather coating composition comprising or consisting of a hydrosilylation curable silicone elastomer composition designed to be used as a topcoat for a synthetic leather material, particularly a silicone-based synthetic leather composite material. A silicone coating as a topcoat for a synthetic leather material which is the cured product of the composition, methods of making the topcoat, synthetic leather material utilizing same and uses of the synthetic leather material products are also disclosed. The topcoat is designed to provide a highly crosslinked silicone matrix containing silicon-free organic micro-particles to minimize or at least decrease change in gloss after abrasion. The leather coating composition comprises a hydrosilylation curable silicone elastomer composition, comprising: (i) at least one organopolysiloxane polymer; (ii) a reinforcing silica filler; (iii) a silicone resin cross-linker having terminal (M) groups comprising silicone bonded hydrogen; (iv) a hydrosilylation catalyst; and (v) silicon-free organic microparticles.

Claims

1. A leather coating composition comprising a hydrosilylation curable silicone elastomer composition, comprising: (i) one or more organopolysiloxane polymer(s) having a viscosity of from 1000 to 500,000 mPa.Math.s at 25 C. with at least 5 weight % of the polymer(s) being unsaturated groups selected from alkenyl groups, alkynyl groups or a mixture thereof as determined using quantitative infra-red analysis in accordance with ASTM E168; (ii) a reinforcing silica filler which may optionally be hydrophobically treated; (iii) a silicone resin cross-linker having terminal (M) groups comprising silicone bonded hydrogen, wherein the molar ratio of SiH groups in component (iii) to unsaturated groups in the composition is from 0.5:1 to 20:1; (iv) a hydrosilylation catalyst; and (v) silicon-free organic microparticles having a number average particle size of from 0.5 to 500 m determined using a field emission scanning electron microscope which are thermally stable up to a temperature of at least 180 C. and which silicon-free organic microparticles are present in the leather coating composition in an amount of from 5 to 35 weight %.

2. The leather coating composition in accordance with claim 1, wherein component (iii) of the hydrosilylation curable silicone elastomer composition comprises one or more of the following: silicone resins comprising or consisting of SiH containing M groups, (CH.sub.3).sub.3SiO.sub.1/2 groups and SiO.sub.4/2 groups, silicone resins comprising or consisting of SiH containing M groups and SiO.sub.4/2 groups, silicone resins comprising or consisting of SiH containing M groups, (CH.sub.3).sub.2SiO.sub.2/2 groups and SiO.sub.4/2 groups, silicone resins comprising or consisting of SiH containing M groups, SiO.sub.4/2 groups and (C.sub.6H.sub.5).sub.3SiO.sub.1/2 groups, and alternatives in which methyl is replaced by phenyl groups or other alkyl groups or mixtures thereof and wherein each of the above may include one or more T groups.

3. The leather coating composition in accordance with claim 1, wherein the silicon-free organic microparticles of component (v) of the hydrosilylation curable silicone elastomer composition are selected from polyurethane microparticles, acrylic microparticles, methacrylic microparticles, polytetrafluoroethylene microparticles, polyester microparticles, polyamide microparticles, polyolefin microparticles, and derivatives and or mixtures thereof.

4. The leather coating composition in accordance with claim 1, wherein the silicon-free organic microparticles of component (v) of the hydrosilylation curable silicone elastomer composition comprise, one or more of polyethylene, polystyrene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polymethyl methacrylate, polybutadiene, polychloroprene, and other vinyl polymers and copolymers thereof; Nylon 6, Nylon 66, and other polyamides; and polyethylene terephthalate, polyacetal, and blends thereof.

5. The leather coating composition in accordance with claim 1, wherein the composition additionally comprises one or more of the following additives: cure inhibitors, cured silicone elastomer powder, pot life extenders, lubricants, diluents, flame retardants, pigments, colouring agents, heat stabilizers, compression set improvement additives, anti-squeak agents and mixtures thereof.

6. The leather coating composition in accordance with claim 5, wherein the lubricant is present and is a reactive lubricant.

7. The leather coating composition in accordance with claim 1, wherein the silicon-free organic microparticles of component (v) of the hydrosilylation curable silicone elastomer composition have a number average particle size of from 0.5 to 100 m determined using a field emission scanning electron microscope.

8. The leather coating composition in accordance with claim 1, which is suitable for a topcoat composition for a silicone-based synthetic leather composite material.

9. A silicone-based synthetic leather composite material comprising a topcoat which is the reaction product of the composition in accordance with claim 1 obtained upon cure.

10. The silicone-based synthetic leather composite material in accordance with claim 9, comprising a textile support layer selected from one or more of polyester fiber, a viscose rayon fiber, a polyamide fiber, nylon, an acrylic fiber, a polyolefin fiber; cellulose fibers and elastic textile materials.

11. A method of preparing a silicone-based synthetic leather composite material with a topcoat, which topcoat is the cured product of the leather coating composition in accordance with claim 1, the method comprising: (i) applying the leather coating composition on to a release liner; (ii) curing the leather coating composition on the release liner to form a cured topcoat; (iii) applying a silicone skin layer on top of the cured topcoat; (iv) curing the silicone skin layer to form a cured skin layer such that the cured topcoat layer is sandwiched between the release liner and the cured skin layer; (v) applying a silicone adhesive composition onto the cured skin layer, (vi) placing a textile support layer on top of the adhesive layer such that the adhesive layer is sandwiched between the skin layer and the textile support layer; (vii) curing the adhesive layer; and (viii) removing the release liner as required.

12. The method in accordance with claim 11, wherein the leather coating composition is applied in a wet film thickness of 10 to 100 m and dries to a corresponding dry coating thickness of about 2 to 50 m.

13. The method in accordance with claim 11, wherein the leather coating composition is applied by one or more of the following: spraying, rolling, brushing, spin coating, dip coating, solvent casting, slot die coating, spray coating, knife coating, or gravure coating.

14. The silicone-based synthetic leather composite material in accordance with claim 9, in or suitable for furniture, decoration, handbags, binders, luggage, garments, phone covers, covers for electronic goods, book covers, footwear, car interiors, car seats, wearable devices and/or medical beds/seats.

15. The leather coating composition in accordance with claim 1, as a topcoat for a synthetic leather, wherein once cured, the topcoat minimizes the change in gloss thereof subsequent to abrasion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0109] The application and uses of the leather coating composition as hereinbefore described will be more apparent from the following further description taken in conjunction with the accompanying Figures in which FIGS. 1-4 are cross-sectional views showing the layers in the structure of a silicone-based synthetic leather composite material during or post manufacture;

DETAILED DESCRIPTION OF THE METHODS OF MAKING A SILICONE-BASED SYNTHETIC LEATHER COMPOSITE MATERIAL USING THE HYDROSILYLATION CURABLE SILICONE ELASTOMER COMPOSITION AS HEREINBEFORE DESCRIBED IN CONJUNCTION WITH THE AFOREMENTIONED FIGURES

[0110] A silicone-based synthetic leather composite material comprising a coating which is the reaction product from the cure of the leather coating composition (5) as hereinbefore described, may comprise several layers of cured liquid silicone rubber (3,4) each having a different function as well as a textile support layer (2). Excluding the topcoat which is made from the leather coating composition described herein, a silicone-based synthetic leather composite material comprises at least a textile support layer (2), an adhesive layer made from a first liquid silicone rubber material (3) and a second or skin layer (4) made from a second liquid silicone rubber material. The adhesive layer (3) is provided as an effective adhesive between the textile support (2) and the second (skin) layer (4). In use the adhesive or first layer (3) is adhered to the textile support layer (2) and adhered or laminated to the skin layer (4). The leather coating composition as hereinbefore described functions as a protective topcoat (5) which is a third layer on top of and bound to the skin layer (4), i.e., the second layer (4) is situated between the adhesive layer (3) and the topcoat layer (5).

[0111] Typically, a release liner (1) is provided to protect the external surface of the silicone-based synthetic leather composite material until required. Dependent on the process relied upon for making the silicone-based synthetic leather composite material. The release liner (1) may be included in the initial combination of layers adhered to the skin layer (4) or to the topcoat (5), dependent on the process preferred. In the former case the release liner (1) may be removed prior to application of the topcoat. In the latter case the topcoat is applied onto the skin before application of the release liner onto the topcoat, or the topcoat is first applied onto the release liner, before application of the additional layers.

[0112] The textile support layer (2) may be made from any suitable textile material for example woven, knitted or non-woven textiles made from synthetic resin fibers, natural fibers and/or, microfibers. These may include but are not restricted to polyester fiber, a viscose rayon fiber, a polyamide fiber, nylon, an acrylic fiber, a polyolefin fiber; cellulose fibers such as cotton; and elastic textile materials, such as spandex, may be used as may mixtures of any two or more of the above. The textile support layer is designed to enhance mechanical strength of silicone leather.

[0113] The leather coating composition as hereinbefore described (i.e., the topcoat layer (5)) is typically applied with a wet film thickness of 10 to 100 m, alternatively 10 to 60 m corresponding to a dry coating thickness of about 2 to 50 m, alternatively 2 to 30 m alternatively 5 to 25 m. It can be cured at any suitable temperature, for example at about 80 C. to 180 C., alternatively from 80 C. to 160 C., alternatively of from 80 C. to 130 C. for a period of from for a suitable period, e.g., between 30 seconds and 20 minutes, alternatively 30 seconds to 10 minutes, alternatively 30 seconds to 5 minutes, alternatively 30 seconds to 2.5 minutes.

[0114] Any suitable liquid silicone rubber composition may be utilised as the adhesive or first layer (3). This must be able to adhere to the textile support layer (2) and typically once cured has a low durometer Shore A hardness e.g., between 20 and 40 and a soft hand feeling to the touch. A commercial example of a suitable hydrosilylation curable liquid silicone rubber composition designed to function as the adhesive layer (3) is Dowsil LCF 8400 Binder, from Dow Silicones Corporation. Dowsil LCF 8400 Binder is provided to the customer in a two-part form as is standard for a hydrosilylation curable composition to avoid premature cure and as such the two-parts of Dowsil LCF 8400 Binder are mixed together immediately prior to use.

[0115] The adhesive layer (3) may be of any desired dry thickness, for example 50 m to 1 mm thick, alternatively 50 to 750 m, alternatively 50 to 500 m, alternatively 100 to 500 m, alternatively 100 to 300 m thick. It can be cured at any suitable temperature, for example at 125 to 180 C., alternatively 130 to 170 C., alternatively 135 to 160 C. for a suitable period of up to 20 minutes, alternatively 1 to 10 minutes, alternatively for a period of from 1.5 minutes to 5 minutes, alternatively 1.5 minutes to 4 minutes.

[0116] As previously indicated the first or adhesive layer (3) is designed to be sandwiched between and to adhere the textile support (2) to the second or skin coating layer (4).

[0117] The second or skin coating composition (4) as hereinbefore described is designed as a protective synthetic leather which is usually bonded to adhesive layer (3). and may be used alone or with a suitable topcoat (5) such as the one described herein. Any suitable liquid silicone rubber composition may be utilised to form the second or skin layer (4) which typically once cured has a larger durometer Shore A hardness than the first or adhesive layer (3) e.g., greater than or equal to () 50, alternatively, greater than or equal to () 60. Commercial examples of suitable liquid silicone rubber compositions curable to function as the second or skin layer (4) are Dowsil LCF 8300 Skin and Dowsil LCF 8500 Skin both from Dow Silicones Corporation, which given they are both hydrosilylation curable liquid silicone rubber compositions are again provided to the user in two-parts which are mixed together immediately prior to use to avoid premature cure in storage prior to use. Dowsil LCF 8300 Skin has a high shore A durometer value of about 65 and provides abrasion resistance and has compared to Dowsil LCF 8500 Skin a relatively low viscosity. The latter is much higher viscosity as it is a fumed silica reinforced version of the former having high mechanical strength. Often a mixture of Dowsil LCF 8300 Skin and Dowsil LCF 8500 Skin is used as the second or skin layer (4) to benefit from the advantages of both compositions.

[0118] The skin layer (4) may be of any suitable dry thickness, for example, the adhesive layer may be of any desired thickness, for example 50 m to 1 mm, thick, 50 to 750 m, alternatively 50 to 500 m, alternatively 50 to 350 m, alternatively 50 to 250 m thick. If the skin layer was applied direct onto the release paper, and the average thickness of the skin layer was determined this was determined by measuring the length and width of a sample of release paper, coating the release paper with the, in this case, skin layer composition, curing same, weighing the resulting release paper coated and calculating the average thickness on the basis of the following formula:

average dry thickness of skinlayer=weight skin layer/(density*width*length)

The average dry coat thickness of each other layer where given, was determined in an analogous fashion by determining the weight of the respective layer and using the above formulation. In each case the density was determined in accordance with ASTM D792. The skin layer can be cured at any suitable temperature, for example at 100 to 150 C., alternatively 110 to 135 C., alternatively 110 to 125 C. for a period of from 30 seconds to 5 minutes, alternatively 30 seconds to 2.5 minutes.

[0119] If desired the final silicone leather product may be post cured at a temperature between about 75 C. and 180 C., generally but not necessarily if desired towards the lower end of the range e.g., from 75 to 120 C. for from 2 to 48 hours, alternatively from 6 to 36 hours, alternatively from 10 to 24 hours.

[0120] The leather coating composition as hereinbefore described may be applied as a topcoat on a preformed silicone-based synthetic leather composite material e.g. (2, 3, 4) as shown in FIG. 2 by any suitable coating method e.g. spraying, rolling, brushing, spin coating, dip coating, solvent casting, slot die coating, spray coating, knife coating, or gravure coating. The adhesive layer (3) and skin layer (4) may be applied via the same means.

[0121] The fabric layer may be adhered to the adhesive layer in any suitable manner e.g., lamination.

[0122] In such circumstances the preformed silicone-based synthetic leather composite material has typically been prepared by several alternative processes. [0123] (i) applying a liquid silicone rubber skin type composition (4) onto a release liner (1), [0124] (ii) curing the skin layer composition in (i) on the release liner (1) to form a cured skin layer (4); [0125] (iii) applying a silicone adhesive composition onto the cured skin layer (4), [0126] (iv) placing a textile support layer (2) on top of the adhesive layer (3) prior to or during cure of adhesive layer (3), such that the adhesive layer (3) is sandwiched between the skin layer (4) and the textile support layer (2); [0127] (v) curing the adhesive layer (3); and [0128] (vi) removing the release liner (1) as required.
The above is depicted in FIGS. 1 and 2 which depict a silicone-based synthetic leather composite material with the release liner present (FIG. 1) and without the release liner (FIG. 2). In the case of FIG. 2 the silicone-based synthetic leather composite material has been prepared and is now ready for application of the topcoat as hereinbefore described by any suitable application means (e.g., spraying, rolling, brushing, spin coating, dip coating, solvent casting, slot die coating, spray coating, knife coating, or gravure coating) as described above on top of the skin layer (4).

[0129] The leather coating composition as hereinbefore described is then applied on to the surface of the skin layer (4) from which the release liner (1) has been removed and is cured to form a protective topcoat on the silicone-based synthetic leather composite material.

[0130] In an alternative embodiment silicone-based synthetic leather composite material may be prepared in a continuous process with a topcoat using the leather coating composition as hereinbefore described in the continuous process. In this case the process followed may be: [0131] (i) applying the leather coating composition as hereinbefore described on to a release liner (1), [0132] (ii) curing the leather coating composition as hereinbefore described on the release liner (1) to form a cured topcoat (5); [0133] (iii) applying a silicone skin layer on top of the cured topcoat (5); [0134] (iv) curing the silicone skin layer to form a cured skin layer (4) such that the cured topcoat layer (5) is sandwiched between the release liner (1) and the cured skin layer (4); [0135] (v) applying a silicone adhesive composition onto the cured skin layer (4), [0136] (vi) placing or laminating a textile support layer (2) on top of the uncured or curing adhesive layer (3); preferably the textile support layer is effectively laminated to the adhesive layer. [0137] (vii) curing the adhesive layer (3) such that post-cure the adhesive layer (3) is sandwiched between the skin layer (4) and the textile support layer (2); and [0138] (viii) removing the release liner (1) as required.

[0139] The different layers for such a process are depicted in FIGS. 3 and 4, wherein FIG. 3 depicts the release liner (1) present and FIG. 4 depicts the final silicone-based synthetic leather composite material with the release liner removed.

[0140] Any suitable release liner may be used for example super matting release paper ARX175DM from the Japan Asahi company, release paper DE-7, DE-90, DE-43C, DE-73J from the Japan Dai Nippon Printing Co., Ltd or semi-matting release paper DE-73M also from the Japan Dai Nippon Printing Co., Ltd. Each cure step may take place in a suitable oven, e.g., by curing and drying in a hot-air oven or may be undertaken in a conveyor oven in the case of a continuous process.

[0141] The above processes depict the preparation of a silicone-based synthetic leather composite material. The reader may appreciate that should the need arise additional layers may be introduced into the material if desired.

[0142] Synthetic leathers, particularly silicone-based synthetic leather composite materials may be designed to have a wide variety of properties given the content of the different layers, e.g. they may have excellent flame retardancy, smoke density, heat resistance, contamination resistance, solvent resistance, hydrolysis resistance, and the like as required for the end use of the leather. End uses envisaged include but are not limited to furniture, decoration, handbags, binders, luggage, garments, phone covers, covers for electronic goods, book covers, footwear, car interiors, car seats, wearable devices and/or medical beds/seats and the like.

EXAMPLES

[0143] In the following examples the hydrosilylation curable silicone elastomer composition which forms the leather coating composition and several comparatives were tested to show the advantage the coating herein described with respect to maintaining gloss after abrasion. All viscosities are measured at 25 C. relying on the cup/spindle method of ASTM D1084-16 Method B, using a Brookfield rotational viscometer with spindle LV-4 (designed for viscosities in the range between 1,000-2,000,000 mPa.Math.s) or a Brookfield rotational viscometer with spindle LV-1 (designed for viscosities in the range between 15-20,000 mPa.Math.s) for viscosities less than 1000 mPa.Math.s and a rotation speed of 10 rpm unless otherwise indicated. Alkenyl and/or alkynyl content and SiH content was determined using quantitative infra-red analysis in accordance with ASTM E 168.

[0144] The ingredients used in the leather coating composition used together with the names given in the following Tables/examples are defined below: [0145] Vinyl-terminated siloxane polymer is Dimethylvinyl terminated polydimethylsiloxane having a viscosity of 65,000 mPa.Math.s at 25 C. having a vinyl content of about 0.08 wt. %; [0146] High vinyl siloxane copolymer is a dimethylvinyl terminated dimethylmethylvinyl polysiloxane copolymer having a viscosity of 15,000 mPa.Math.s at 25 C. and a vinyl content of about 8.0 wt. %; [0147] Vinyl-terminated siloxane copolymer 2 is a dimethylvinyl terminated dimethylmethylvinyl polysiloxane copolymer having a viscosity of 300 mPa.Math.s at 25 C. and a vinyl content of about 1.15 wt. %; [0148] Fumed silica is HDK T30P pyrogenic silica (Wacker Chimie) having a BET surface area of 300 m.sup.2/g; [0149] HMDZ is hexamethyldisilazane; [0150] MVD (Methylvinyl diol) is a Dimethylhydroxy terminated polydimethylmethylvinylsiloxane having a viscosity of about 30 mPa.Math.s at 25 C. and a vinyl content of about 12.0 wt. %; [0151] Platinum catalyst is a platinum catalyst in a solution of polydimethylsiloxane having about 5000 ppm of platinum metal with respect to the rest of the composition; [0152] Inhibitor is Methyl(tris(1,1-dimethyl-2-propynyloxy))silane; [0153] Silicone elastomer powder is Dowsil 23N Additive (Dow Silicones Corporation); [0154] Resinous SiH crosslinker is SiH dimethyl terminated resinous SiH polysiloxane having a viscosity of 25 mPa.Math.s at 25 C. and a silicon bonded hydrogen content of about 9,000 ppm; [0155] Polyurethane microparticles are RHU-5070D Polyurethane microparticles from Dainichiseika-ave. particle size 1-10 m (supplier information); [0156] Acrylic microparticles 1 are Chemisnow MZ-5HN by Soken Chemical & Engineering ave. particle size 1-10 m (supplier information); [0157] Acrylic microparticles 2 are Chemisnow MX-40T by Soken Chemical & Engineering ave. particle size about 0.4 m (supplier information); [0158] Lubricant is a C24-28 olefin from Nanjing Chemical Material Corp.

[0159] Table 1 provides details of the starting materials used for the silica masterbatch in the composition described below. The fumed silica was mixed with the Vinyl-terminated siloxane polymer in the presence of the small molecules which acted as hydrophobing treating agents of the silica resulting in the in-situ treatment of the silica whilst the silica and polymer are being mixed. As previously indicated the polymer used may be component (i) or a mixture of component (i) and another polymer if desired but in this case no component (i) is present in the masterbatch.

TABLE-US-00001 TABLE 1 Fumed Silica Masterbatch Wt. % Fumed silica 29.7% Vinyl-terminated siloxane polymer 62.4% HMDZ 5.5% Divinyl teteramethyldisilazane 0.3% Methylvinyl diol (MVD)* 0.35% Water 1.75%

[0160] Several LSR compositions were prepared as examples (Ex. 1-4) and comparative examples (comp. 1-5) in two-part compositions. The total composition of each composition after part A and part B were mixed is depicted in Tables 2a (examples) and 3a (comparatives).

[0161] Prior to mixing, the part A composition incorporated the following: [0162] High vinyl siloxane copolymer, [0163] A proportion of the masterbatch, [0164] Platinum catalyst, [0165] Lubricants, when present, a proportion of micro-particles and diluent (when present). The diluent is designed to evaporate during the cure process.

[0166] The part B composition incorporated the following: [0167] Remainder of the masterbatch, [0168] Resinous SiH crosslinker, [0169] Inhibitor when present, as well as the remainder of the micro-particles and any diluent present Diluent. The diluent is designed to evaporate during the cure process.

[0170] Shortly prior to use the Part A compositions and their respective part B compositions were mixed together in a 1:1 weight ratio to make the final hydrosilylation curable silicone elastomer composition under test.

TABLE-US-00002 TABLE 2a Compositions of Examples (wt. %) Ex. 1 Ex. 2 Ex. 3 Ex. 4 High vinyl siloxane copolymer 22.46 22.46 24.43 18.87 Masterbatch 46.69 46.69 50.81 39.24 Resinous SiH crosslinker 14.43 14.43 12.72 12.14 Lubricant 5.35 5.35 4.49 Silicone elastomer powder 3.88 Polyurethane microparticles 7.13 24.95 Acrylic microparticles 1 10.69 3.56 7.75 Inhibitor 0.09 0.09 0.1 0.07 Platinum catalyst 0.29 0.29 0.31 0.24

[0171] Once prepared the topcoat composition was utilised in the preparation of a silicone-based synthetic leather composite material via the following process. The skin layer (4) used was a mixture of Dowsil LCF 8300 Skin and Dowsil LCF 8500 Skin and adhesive layer (3), was in the form of Dowsil LCF 8400 Binder and before curing this underwent a lamination bonding process to a microfiber-based textile layer (2) which combination was then cured at a temperature of 150 C. for a period of three minutes. [0172] 1) the mixture of the topcoat was applied onto a release liner and cured at a temperature of 120 C. for 1.4 minutes (min). The dry film thickness was determined to be about 10 m. [0173] 2) The skin layer was then applied onto the topcoat and cured under the same condition. The thickness of the adhesive layer was 100-150 m. [0174] 3) The adhesive layer was applied to the top of the skin layer and a lamination bonding process was employed to attach the fabrics. Then the combination was cured at 150 C. for 3 min. the thickness of the adhesive layer is 150-250 m. [0175] 4) The release liners were then removed to obtain the top coated silicone leather samples, 5) Finally the silicone leather material was post-cured at a temperature of 80 C. for 16-20 hours.

[0176] The resulting silicone leather was then analysed using a Taber abrasion test using TABER Abraser (Abrader) Model 5131 was used for the testing. The Taber abrasion test is used to evaluate the abrasion resistant performance of the leather samples. Three samples of each example or comparative underwent 500 cycles of abrasion using a CS-10 Wheel and a 1 kg weight. After the abrasion step and prior to evaluation, the abraded surface was cleaned with deionized water and allowed to air dry. Each sample was then visually assessed and any objectionable changes in gloss, color or texture were noted. To pass the test, there should be substantially no wear-through of the coating or any objectionable changes in gloss, color or grain.

[0177] The results for the examples having a topcoat in accordance with the disclosure herein are provided in Table 2b.

TABLE-US-00003 TABLE 2b Properties of the topcoat Ex. 1 Ex. 2 Ex. 3 Ex. 4 Taber, CS-10 Pass Pass Pass Pass Gloss Pass (SC) Pass (SC) Pass (SC) Pass (SC) Grain Little change Little change Little change Little change Color No change No change No change No change Wear-through no no no no (SC) stands for slight change.

[0178] The high crosslinking density due to the nature of the polymer and cross-linker is thought to restrict the chain mobility and thus minimized adhesive contact. This resulted in an abrasive pattern was avoided, and the gloss would not decrease after abrasion. On the other hand, micro-particles in the topcoat would appear on the surface after abrasion. As a result, although the small grains were worn away, the appeared micro-particles would help to compensate the loss of surface roughness, so as to avoid increased gloss.

[0179] Analogous testing was then carried out on silicone leather top coated with the comparative compositions using the same processes and test methods as described above. The compositions for the topcoats are depicted in Table 3a and the results are depicted in Table 3b.

TABLE-US-00004 TABLE 3a Composition of comparative examples Comp. 1 Comp. 2 Comp. 3 Comp. 4 Comp. 5 High vinyl siloxane 25.14 20.59 18.87 22.46 copolymer Vinyl-terminated siloxane 22.46 copolymer 2 Masterbatch 46.69 52.28 42.80 39.24 46.69 Resinous SiH crosslinker 14.43 16.17 13.23 12.13 14.43 Lubricant 5.35 5.99 4.90 4.49 5.35 Silicone elastomer powder 18.14 24.95 Acrylic microparticles 1 10.69 Acrylic microparticles 2 10.69 Inhibitor 0.09 0.1 0.08 0.08 0.09 Platinum Catalyst 0.29 0.32 0.26 0.24 0.29

TABLE-US-00005 TABLE 3b Properties of the Comparative examples. Comp. 1 Comp. 2 Comp. 3 Comp. 4 Comp. 5 Taber, CS-10 Fail, (SDG) Fail, (SDG) Fail, (SDG) Fail, (SDG) Fail, (SDG) gray value 0.963 1.049 0.978 0.970 0.965 gloss Fail, (SDG) Fail, (SDG) Fail, (SDG) Fail, (SDG) Fail, (SDG) grain Little change Little change Little change Little change Little change color No change No change No change No change No change Wear-through no no no no no SDG stands for significant decrease in gloss and gray value stands for the change in gray value.

[0180] Examples 1, 2 and 3 passed Taber test with no obvious change in glossiness. Comparative examples 1, 3, 4, 5 failed due to significantly decreased gloss, while comparative example 2 failed due to significantly increased gloss. It can be seen from Comp. 5 that the particle size of the microparticles needs to be at least 5 m. In comp.1 Vinyl-terminated siloxane copolymer 2 is used instead of the High vinyl siloxane copolymer used in the examples. The elastomer resulting from curing comp. 1 has a lower crosslinking density and as such the necessity of High vinyl siloxane copolymer can be appreciated given the results in Table 3b.