COATING COMPOSITION AND ITS USES

Abstract

The present disclosure relates to a silicone elastomeric coating composition for synthetic leather, particularly silicone-based synthetic leather, a silicone elastomeric coating (e.g., a topcoat) formed as a reaction product of the cure of the coating composition, methods of making the topcoat and synthetic leather utilizing the same and uses of synthetic leather products. The topcoat is designed to provide synthetic leather with an improved abrasion and scratch resistant topcoat.

Claims

1. A leather coating composition comprising a hydrosilylation curable silicone elastomer composition comprising: (i) one or more polydiorganosiloxane polymer(s) having a viscosity of from 1000 to 500,000 mPa.Math.s at 25° C. and an alkenyl group and/or alkynyl group content of at least 5% by weight of the polymer(s) per molecule; (ii) a reinforcing filler; (iii) a silicone resin cross-linker having terminal groups comprising silicone bonded hydrogen; (iv) a hydrosilylation catalyst; (v) a cured silicone powder; and (vi) an eco-diluent.

2. The leather coating composition in accordance with claim 1, wherein the silicone resin cross-linker (iii) comprises one or more of the following: silicone resins comprising or consisting of Si—H containing M groups, (CH.sub.3).sub.3SiO.sub.1/2 groups and SiO.sub.4/2 groups, silicone resins comprising or consisting of Si—H containing M groups and SiO.sub.4/2 groups, silicone resins comprising or consisting of Si—H containing M groups, (CH.sub.3).sub.2SiO.sub.2/2 groups and SiO.sub.4/2 groups, silicone resins comprising or consisting of Si—H 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 optionally includes may include one or more T groups.

3. The leather coating composition in accordance with claim 1, wherein the cured silicone elastomer powder (v) has an average particle size of from 0.01 to 100 μm.

4. The leather coating composition in accordance with claim 1, wherein the eco-solvent (vi) comprises or consists of isopentadecane, isohexadecane, isoheptadecane, isooctadecane, isononadecane, or mixtures thereof, or comprises or consists of trimethyl terminated polydimethylsiloxane having a viscosity of from greater than or equal to (≥) 5 mPa.Math.s at 25° C. to equal or less than (≤) 100 mPa.Math.s at 25° C.

5. The leather coating composition in accordance with claim 4, wherein the eco-solvent (vi) comprises or consists of isohexadecane.

6. The leather coating composition in accordance with claim 1, further comprising one or more additives selected from the group consisting of one or more low viscosity polydiorganosiloxane polymers having at least one, optionally at least two alkenyl and/or alkynyl group(s) per molecule and a viscosity of from 100 to 750 mPa.Math.s at 25° C., inhibitors, non-reinforcing fillers, electrically conductive fillers, non-conductive fillers, pot life extenders, flame retardants, pigments, colouring agents, chain extenders, heat stabilizers, compression set improvement additives, anti-squeak agents, anti-freeze agents, and/or biocides.

7. The leather coating composition in accordance with claim 1, further defined as a topcoat composition for a silicone-based synthetic leather.

8. A silicone-based synthetic leather comprising a topcoat which is the reaction product of the topcoat composition in accordance with claim 7 obtained upon cure.

9. The silicone-based synthetic leather in accordance with claim 8, comprising a textile support layer selected from one or more of a polyester fiber, a viscose rayon fiber, a polyamide fiber, nylon, an acrylic fiber, a polyolefin fiber, cellulose fibers and elastic textile materials.

10. The silicone-based synthetic leather in accordance with claim 8, wherein the topcoat has a Wyzenbeek abrasion resistance of greater than or equal to 75,000 in accordance with ASTM D4157-13.

11. A method of applying a silicone-based synthetic leather with the topcoat composition in accordance with claim 7 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.

12. A method of applying a silicone-based synthetic leather with a topcoat composition, the method comprising: (i) applying the leather coating composition in accordance with claim 1 on to a release paper; (ii) curing the coating composition on the release paper 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 paper and the cured skin layer; (v) applying a silicone adhesive composition onto the cured skin layer to form an adhesive 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 paper.

13. The silicone-based synthetic leather in accordance with claim 8, in or for furniture, decoration, handbags, luggage, garments, footwear, car interiors, or medical beds/seats.

14. The leather coating composition in accordance with claim 1, wherein the reinforcing filler (ii) is treated with at least one filler treating agent.

15. The silicone-based synthetic leather in accordance with claim 9, wherein the topcoat has a Wyzenbeek abrasion resistance of greater than or equal to 75,000 in accordance with ASTM D4157-13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0080] 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 material during or post manufacture;

[0081] FIG. 5 is an image showing the “whitening” stretch marks caused by stretching a silicone based synthetic leather when after using solvents like trimethyl terminated polydimethylsiloxane having a viscosity of about 1 mPa.Math.s at 25° C.; and

[0082] FIG. 6 is an image showing the non-appearance of “whitening” stretch marks caused when stretching a silicone based synthetic leather having a coating resulting from the cure of the preceding leather coating composition as a topcoat in accordance with an embodiment herein.

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

[0083] A silicone-based synthetic leather comprising a coating which is the reaction product from the cure of the leather coating composition (5) as hereinbefore described, truly 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, a synthetic silicone leather 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).

[0084] 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 polyimide 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.

[0085] The coating composition as hereinbefore described is designed as a protective synthetic leather topcoat. It may be applied to any silicone-based synthetic leather. 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 DoNAisil™ LCF 8400 Binder are mixed together immediately prior to use.

[0086] 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).

[0087] 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 and Dowsil™ LCF 8500 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.

[0088] The leather coating composition as hereinbefore described may be applied as a topcoat on a preformed silicone-based synthetic leather 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.

[0089] In such circumstances the preformed silicone-based synthetic leather material has typically been prepared by [0090] (i) applying a liquid silicone rubber skin type composition (4) onto a release paper (1), curing the skin layer composition in (i) on the release paper (1) to form a cured skin layer (4); [0091] (iii) applying a silicone adhesive composition onto the cured skin layer (4), [0092] (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); [0093] (v) curing the adhesive layer (3); and [0094] (vi) removing the release paper (1) as required.
The above is depicted in FIGS. 1 and 2 which depict a silicone-based synthetic leather material with the release layer present (FIG. 1) and without the release layer (FIG. 2). In the case of FIG. 2 the silicone-based synthetic leather 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).

[0095] The leather coating composition as hereinbefore described is then applied on to the surface of the skin layer (4) from which the release paper (1) has been removed and is cured to form a protective topcoat on the silicone-based synthetic leather material. The leather coating composition is, for example, applied at a wet film thickness of 10 to 100 μm, alternatively 10 to 60 μm corresponding to a dry film thickness of about 2 to 50 μm, alternatively 2 to 30 μm alternatively 5 to 25 μm.

[0096] Following application of the leather coating composition, curing is carried out by heating the coated material at a temperature of from about 80° C. to 180° C., alternatively from 80° C. to 150° C., alternatively of from 80° C. to 130° C. for about 1 to 20 minutes to cure the leather coating composition thereon. When the curing temperature is low, curing takes a relatively longer time; when the curing temperature is too high, the fabric base may undergo deterioration due to the heat. Hence, a curing temperature of from 80 to 150° C., alternatively 80° C. to 130° C. is preferred.

[0097] In an alternative embodiment a silicone-based synthetic leather 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: [0098] (i) applying the leather coating composition as hereinbefore described on to a release paper (1), [0099] (ii) curing the leather coating composition as hereinbefore described on the release paper (1) to form a cured topcoat (5); [0100] (iii) applying a silicone skin layer on top of the cured topcoat (5); [0101] (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 paper (1) and the cured skin layer (4); [0102] (v) applying a silicone adhesive composition onto the cured skin layer (4), [0103] (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. [0104] (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 [0105] (viii) removing the release paper (1) as required.

[0106] The different layers for such a process are depicted in FIGS. 3 and 4, wherein FIG. 3 depicts the release layer (1) present and FIG. 4 depicts the final silicone-based synthetic leather material with the release paper removed.

[0107] Any suitable release paper may be used for example super matting release paper ARX175DM from the Japan Asahi company. 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.

[0108] The topcoat layer (5) as hereinbefore described is typically applied on to the release paper (1) with a wet film thickness of 10 to 100 μm, alternatively 10 to 60 μm corresponding to a dry coating thickness of about 2 to 50 prn, alternatively 2 to 30 μm alternatively 5 to 25 μm. It can be cured at any suitable temperature, for example at about 80° C. to 180° C., alternatively from 80° C. to 150° C., alternatively of from 80° C. to 130° C. for a period of from 30 seconds to 5 minutes, alternatively 30 seconds to 2.5 minutes.

[0109] The skin coat layer (4) is typically from 0.05 to 1 mm thick after cure, alternatively 0.05 to 0.8 mm thick, alternatively 0.1 to 0.4 mm thick. It 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.

[0110] The adhesive coat layer (3) is typically from 0.05 to 1 mm thick after cure, alternatively 0.1 to 0.75 mm 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 period of from 1.5 minutes to 5 minutes, alternatively 1.5 minutes to 4 minutes.

[0111] The above processes depict the preparation of a silicone based synthetic leather material. The reader may appreciate that should the need arise additional layers may be introduced into the material if desired.

[0112] Synthetic leathers, particularly silicone-based synthetic leathers 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, luggage, garments, footwear, car interiors, medical beds/seats and the like,

EXAMPLES

[0113] In the following examples the coating composition and several comparatives are tested to show the advantage the coating herein described with respect to provide sufficient abrasion resistance (e.g. a Wyzenbeek abrasion resistance of greater than or equal to (≥) 75,000, alternatively greater than or equal to (≥) 100,000 times test), as well as suitable scratch resistance i.e. no white line or crack after strong nail scratching and no whitening caused by stretching. All viscosities are measured at 25° C. relying on the cup/spindle method of ASTM D1084-16 Method B, using an appropriate spindle for the viscosity range unless otherwise indicated. Alkenyl and/or alkynyl content and Si—H content was determined using quantitative infra-red analysis in accordance with ASTM E168.

[0114] The ingredients used in the leather coating composition used in the following examples are defined in Table 1 below

TABLE-US-00001 TABLE 1 Names used in Tables Detailed Description Vinyl-term PDMS polymer Dimethylvinyl terminated polydimethylsiloxane having a viscosity of 65,000 mPa .Math. s at 25° C. having a vinyl content of about 0.08 wt. % High vinyl PDMS polymer 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. % Low viscosity vinyl PDMS dimethylvinyl terminated dimethylmethylvinyl polymer polysiloxane copolymer having a viscosity of 300 mPa .Math. s at 25° C. and a vinyl content of about 1.15 wt. % Fumed silica HDK ® T30P pyrogenic silica (Wacker Chimie) having a BET surface area of 300 m.sup.2/g HMDS hexamethyldisilazane MVD (Methylvinyl diol) Dimethylhydroxy terminated polydimethylmethylvinylsiloxane having a viscosity of about 30 mPa .Math. s at 25° C. and a vinyl content of about 12.0 wt. % Divinyltetramethyldisilazane Platinum catalyst Platinum catalyst in a solution of polydimethylsiloxane having about 5000 ppm of platinum metal with respect to the rest of the composition Inhibitor Methyl(tris(1,1-dimethy1-2-propynyloxy))silane Silicone elastomer powder Dowsil ® 23N (Dow Silicones Corporation) Resinous SiH crosslinker Si—H dimethyl terminated resinous Si—H polysiloxane containing M(H) functions copolymer having a viscosity of 25 mPa .Math. s at 25° C. and a silicon bonded hydrogen content of about 9,000 ppm Isohexadecane Trimethylsiloxy terminated Trimethyl terminated dimethylmethylSi-H SiH cross linker polysiloxane copolymer having a viscosity of 30 mPa .Math. s at 25° C. and a silicon bonded hydrogen content of about 16,000 ppm Low viscosity silicone fluid trimethyl terminated polydimethylsiloxane having a viscosity of 1 mPa .Math. s at 25° C.

[0115] Table 2 provides details of the starting materials used for the silica masterbatch in the composition described below. The fumed silica was mixed with the vinyl-term PDMS 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-00002 TABLE 2 Fumed Silica Masterbatch Wt. % Fumed silica 29.7% Vinyl-term PDMS polymer 62.4% HMDS  5.5% Divinyl teteramethyldisilazane  0.3% Methylvinyl diol (MVD)* 0.35% Water 1.75%

[0116] Several LSR compositions were prepared as examples and comparative examples in two-part compositions. The Part A compositions are depicted in Table 3a and the Part B compositions are depicted in Table 3b. 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 composition under test.

TABLE-US-00003 TABLE 3a Part A compositions Ex.1 Ex. 2 Ex. 3 Comp. 1 Comp. 2 Comp. 3 Comp. 4 (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) Fumed silica LSR 8.00 12.00 10.94 21.37 30.69 12.00 6.00 master batch (29.7% silica) Vinyl-term 6.00 PDMS polymer High vinyl 22.69 34.05 5 28.31 34.05 34.05 PDMS polymer Low viscosity 21.48 vinyl PDMS polymer MVD 5.3 Silicone 14.05 13.57 7.05 9.05 13.57 13.57 elastomer powder Isohexadecane 55.00 40.00 50.00 50.00 60.00 Low viscosity 40.00 40.00 silicone fluid Platinum catalyst 0.26 0.38 0.26 0.32 0.26 0.38 0.38 solution

TABLE-US-00004 TABLE 3b Part B compositions Ex.1 Ex. 2 Ex. 3 Comp. 1 Comp. 2 Comp. 3 Comp. 4 (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) Fumed silica LSR 26.88 40.32 24.31 33.60 26.88 40.32 20.32 master batch (29.7% silica) Vinyl-term PDMS 20.00 polymer Low viscosity vinyl 12.57 PDMS polymer Isohexadecane 60.00 40.00 50.00 50.00 60.00 Low viscosity 40.00 40.00 silicone fluid Inhibitor 0.08 0.12 0.08 0.10 0.08 0.12 0.12 Resinous SiH 13.04 19.56 13.04 16.3 19.56 19.56 crosslinker containing M(H) functions Trimethylsiloxy 13.04 terminated SiH cross linker

[0117] When the Part A and Part B compositions were mixed together in their respective compositions the final compositions, the wt. % levels of fumed silica, high vinyl polymer, and resinous cross-linker are shown in Table 3c below after evaporation of eco-solvent.

TABLE-US-00005 TABLE 3c key ingredients in dry topcoat layer after cure and evaporation of eco-solven Ex.1 Ex. 2 Ex. 3 Comp. 1 Comp. 2 Comp. 3 Comp. 4 (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) Fumed silica 12.41 12.95 10.46 16.32 21.3 12.95 6.51 dosage High vinyl 27.17 28.37 5.00 28.37 0 28.37 28.37 PDMS polymer Low viscosity 17.02 vinyl PDMS polymer Silicone 16.82 11.31 7.05 0 11.31 11.31 11.31 elastomer powder Resinous SiH 15.62 16.30 13.04 16.30 0 16.30 16.30 crosslinker containing M(H) functions Trimethylsiloxy 16.30 terminated SiH cross linker

[0118] A silicone-based synthetic leather having a topcoat using the compositions in Tables 3a and 3b was prepared in a continuous mode in the manner shown in FIGS. 3 and 4 herein. In this case a topcoat composition as depicted in Tables 3a and 3b was mixed and applied onto a continuous release paper (super matting release paper ARX175DM from Japan Asahi Company) in a dry film thickness of between 10-15 μm. Once applied on to the release paper the topcoat (5) was cured at a temperature of 120° C. for 1.0-1.5 minutes. A skin layer was then applied on top of topcoat (5). The skin layer (4) was a mixture of are Dowsil™ LCF 8300 Skin and Dowsil™ LCF 8500 Skin and was the mixture was applied to a thickness of 0.12-0.25 mm and subsequently cured at 120° C. for 1.5 minutes. An adhesive layer (3), in the form of Dowsil™ LCF 8400 Binder was then applied on skin layer (4) at a thickness of 0.12-0.25 mm 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. After removing the release paper (1) as required, the final silicone-based synthetic leather samples were additionally post-cured at a temperature of 80° C. for 16-20 hours or 150° C. for 2-3 hours.

Physical Testing

[0119] The samples prepared performance tested using the Wyzenbeek abrasion test is used to measure the silicone leather's ability to withstand abrasion according to ASTM D4157-13. The scratch resistance test is used to measure scratch resistant ability of silicone leather per Ford BN 108-13 (for this technique, the observer uses a controlled light source to visually inspect each scratch line and rates according to a Rating Scale 1 to 5 (1=no scratch line at all; 5=severe scratch line). The whitening discolouration on stretch marks was observed by using thumb to stretch the samples of synthetic silicone leather analysed. The results are depicted in Table 4 below.

TABLE-US-00006 TABLE 4 Performance Testing Ex.1 Ex. 2 Ex. 3 Comp. 1 Comp. 2 Comp. 3 Comp. 4 (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) Wyzenbeek Pass Pass Pass Fail Fail Pass Pass abrasion test (Pass 100,000 times?) Scratch 1~2 1~2 1~2 1~2 1 1~2 4~5 resistance test Stretching No No No No No Yes Yes whitening (Yes/No?) Repeated use of >15 >15 >15 >15 2~3 >15 >15 structure release paper (Times)

[0120] Examples 1, 2 and 3 passed both the Wyzenbeek abrasion test and the stretching/whitening test and therefore show an optimum performance. Comparative examples 1 and 2 were seen to fail the Wyzenbeek abrasion test despite passing the stretching/whitening test and as such were not suitable. Comparative examples 3 and 4 were also not deemed suitable for use but for a different reason, they passed the Wyzenbeek abrasion test but failed the stretching/whitening test. FIG. 5 shows the leather product coated with the cured product of the composition of comparative example 3 in which whitening is seen upon stretching (having used a trimethyl terminated polydimethylsiloxane with a viscosity of 1 mPa.Math.s at 25° C.) whilst when the composition of example 1 herein was used using isohexadecane as the eco-solvent in the leather coating composition no discoloration was visualized as shown in FIG. 6.