COATING COMPOSITION AND ITS USES

Abstract

A silicone/polyurethane synthetic leather topcoat composition is disclosed. The silicone/polyurethane synthetic leather topcoat composition is a hydrosilylation curable silicone elastomer composition which provides good adhesion to polyurethane and is used to provide a topcoat for a silicone/polyurethane composite synthetic leather material. The topcoat is the cured product of the composition. Also disclosed are methods of making the topcoat and the silicone/polyurethane composite synthetic leather material as well as uses of the silicone/polyurethane composite synthetic leather material.

Claims

1. A silicone/polyurethane synthetic leather topcoat composition comprising: (i) at least one organopolysiloxane polymer having at least two unsaturated groups per molecule which unsaturated groups are selected from alkenyl groups, alkynyl groups or a mixture thereof; having a viscosity of from 100 to 500,000 mPa.Math.s at 25? C.; (ii) an inorganic reinforcing filler optionally hydrophobically treated with one or more filler treating agents; (iii) a polyorganosiloxane containing at least two or optionally at least three silicon bonded hydrogen (SiH) groups per molecule; (iv) a hydrosilylation catalyst; (v) an adhesion promoter comprising a combination of zirconium acetylacetonate in an amount of from 1 to 5 wt. % of the composition with 1,3,5-tris[3-(trimethoxysilyl)propyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and/or one or more epoxy silanes of the formula ##STR00006## wherein R.sup.5 is an alkyl group having 1 to 6 carbons, R.sup.6 is an alkoxy group having 1 to 6 carbons and z=0, 1 or 2, or a mixture thereof, in an amount of from 1 to 6 wt. % of the composition; and (vi) an eco-solvent; and optionally (vii) a cured silicone powder.

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

3. The silicone/polyurethane synthetic leather topcoat composition in accordance with claim 1, wherein component (vii) is present and wherein the cured silicone elastomer powder (vii) has an average particle size of from 0.01 to 100 ?m.

4. The silicone/polyurethane synthetic leather topcoat composition in accordance with claim 1, wherein the eco-solvent (vi) comprises or consists of isopentadecane, isohexadecane, isoheptadecane, isooctadecane, isononadecane and mixtures thereof or 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 silicone/polyurethane synthetic leather topcoat composition in accordance with claim 1, additionally comprising one or more of the following additives: cure inhibitors, cured silicone elastomer powder, pot life extenders, lubricants, flame retardants, pigments, colouring agents, heat stabilizers, compression set improvement additives, anti-squeak agents and mixtures thereof.

6. The silicone/polyurethane synthetic leather topcoat composition in accordance with claim 1, wherein the epoxysilane of component (v) is present and selected from one or more of the following: 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, (3-glycidoxypropyl)methyldiethoxysilane, and (3-glycidoxypropyl)methyldimethoxysilane.

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

8. The silicone/polyurethane composite synthetic leather material in accordance with claim 7, comprising the following layers: (a) a textile support layer; (b) a sponge/adhesive layer adhered to layer (a); (c) a polyurethane skin layer adhered to layer (b); and (d) the topcoat wherein layer (b) is substantially sandwiched between layers (a) and (c) and layer (c) is substantially sandwiched between layers (b) and (d).

9. A method of preparing a silicone/polyurethane composite synthetic leather material having a topcoat, the method comprising the step of: adhering and curing the silicone/polyurethane synthetic leather topcoat composition in accordance with claim 1 to a suitable-polyurethane skin layer.

10. A method of preparing a silicone/polyurethane composite synthetic leather material having a topcoat, the method comprising the following steps: applying a polyurethane skin layer (c) onto a release liner and then drying the polyurethane skin layer (c); applying a sponge/adhesion layer (b) onto the polyurethane skin layer (c) and applying a textile support layer (a) on the side of the sponge/adhesion layer (b) remote from the polyurethane skin layer (c) by lamination commencing prior to drying the sponge/adhesion layer (b) or after the same has been partially dried; to form a partially prepared silicone/polyurethane composite synthetic leather material; when required, removing the release liner; and applying and curing a layer of the silicone/polyurethane synthetic leather topcoat composition (d) in accordance with claim 1 on the polyurethane skin layer (c).

11. A method of preparing a silicone/polyurethane composite synthetic leather material with a topcoat, the method comprising the following steps: applying and curing a silicone/polyurethane synthetic leather topcoat composition in accordance with claim 1 onto a release liner to form a silicone/polyurethane synthetic leather topcoat (d); applying and then drying a polyurethane skin layer (c) on the cured silicone/polyurethane synthetic leather topcoat (d); applying a sponge/adhesion layer (b) onto the polyurethane skin layer (c); and applying a textile support layer (a) on the side of the sponge/adhesion layer (b) remote from the polyurethane skin layer (c) by lamination commencing prior to drying the sponge/adhesion layer (b) or after the same has been partially dried.

12. The method of preparing a silicone/polyurethane composite synthetic leather material with a topcoat in accordance with claim 9, wherein the silicone/polyurethane synthetic leather topcoat composition is applied and cured to give a dry film thickness of about 2 to about 50 ?m.

13. The method of preparing a silicone/polyurethane composite synthetic leather material with a topcoat in accordance with claim 9, wherein the silicone/polyurethane synthetic leather topcoat composition is applied using one or more of the following techniques selected from spraying, rolling, brushing, spin coating, dip coating, solvent casting, slot die coating, spray coating, knife coating, or gravure coating.

14. The method of preparing a silicone/polyurethane composite synthetic leather material with a topcoat in accordance with claim 9, wherein the polyurethane skin layer is activated, prior to being coated with the silicone/polyurethane synthetic leather topcoat composition, using an activation method selected from plasma treatment, corona discharge treatment, UV-C/ozone or vacuum-UV irradiation.

15. (canceled)

Description

EXAMPLES

[0147] In the following examples the hydrosilylation curable silicone elastomer composition which forms the silicone/polyurethane synthetic leather topcoat composition and several comparatives are 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 an appropriate spindle for the viscosity range unless otherwise indicated. Alkenyl and/or alkynyl content and SiH content were all determined using quantitative infra-red analysis in accordance with ASTM E168.

[0148] The ingredients used in the silicone/polyurethane synthetic leather topcoat composition used together with the names given in the following Tables/examples are defined below: [0149] 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. %; [0150] 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. %; [0151] 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. %; [0152] Fumed silica is HDK? T30P pyrogenic silica (Wacker Chimie) having a BET surface area of 300 m.sup.2/g; [0153] HMDZ is hexamethyldisilazane; [0154] 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. %; [0155] 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; [0156] Inhibitor is Methyl(tris(1,1-dimethyl-2-propynyloxy))silane; [0157] Silicone elastomer powder is Dowsil? 23N (Dow Silicones Corporation); [0158] Trimethyl terminated SiH cross linker is a trimethyl terminated dimethylmethylhydrogen polyorganosiloxane co-polymer having a viscosity of about 45 mPa.Math.s at 25? C. and a silicon bonded hydrogen content of about 7220 ppm; [0159] 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; [0160] ZrAcAc Masterbatch is zirconium acetylacetonate in a 50:50 masterbatch of Vinyl-terminated [0161] siloxane polymer [0162] Silane 1 is 3-Glycidoxypropyltrimethoxysilane [0163] Silane 2 is 1,3,5-tris[3-(trimethoxysilyl)propyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione [0164] Silane 3 is Bis(trimethoxysilyl)hexane

[0165] 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%

[0166] Several LSR compositions were prepared as examples (Ex. 1-11) and comparative examples (comp. 1-9) in two-part compositions.

[0167] Prior to mixing, the part A composition incorporated the following: High vinyl siloxane copolymer, [0168] A proportion of the masterbatch depicted in Table 1, [0169] Platinum catalyst, [0170] ZrAcAc Masterbatch and [0171] a proportion of eco-solvent. The eco-solvent is designed to evaporate during the cure process.

[0172] The part B composition incorporated the following: [0173] Remainder of the masterbatch, [0174] Resinous SiH crosslinker, [0175] Inhibitor when present, as well as the silane 1, 2 and/or 3 and the remainder of the eco-solvent present. The eco-solvent is designed to evaporate during the cure process.

[0176] 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 silicone/polyurethane synthetic leather topcoat composition under test.

[0177] In the following examples once mixed the silicone/polyurethane synthetic leather topcoat compositions prepared were applied onto a pre-prepared polyurethane composite material having a textile support layer, a foam adhesion layer laminated to the former and a beige coloured polyurethane (PU) skin layer which was prepared using a polyether polyol. The topcoat used in each example/comparative example was applied onto the PU skin layer and cured for approximately 5 minutes in an oven at an average temperature of 150? C.

TABLE-US-00002 TABLE 2a Part A compositions for Ex. 1 to 7 (wt. %) Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Fumed silica LSR master batch 0.00 8.00 7.00 7.00 10.94 40.00 24.00 (29.7% silica, 62% low vinyl PDMS polymer) High vinyl PDMS polymer 6.30 2.30 6.30 6.30 5.00 0.00 0.00 Vinyl-terminated siloxane 24.55 17.69 15.69 15.69 21.48 6.70 6.70 copolymer 2 Methyl vinyl diol (MVD) 3.95 3.95 3.95 3.95 5.30 0.00 0.00 Silicone elastomer powder 26.02 24.70 27.92 27.92 7.02 0.00 16.00 ZrAcAc Masterbatch 2.00 3.00 2.00 4.00 3.00 3.00 3.00 Eco-solvent 36.78 40.00 36.78 34.78 47.00 50.00 50.00 Platinum catalyst solution 0.4 0.36 0.36 0.36 0.26 0.30 0.30

TABLE-US-00003 TABLE 2b Part B compositions for Ex. 1 to 7 (wt. %) Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Fumed silica 40.88 35.86 40.08 40.08 24.31 37.98 37.98 LSR master batch (29.7% silica, 62% low vinyl PDMS polymer) Vinyl-terminated 8.22 8.50 9.00 9.00 12.57 3.42 3.42 siloxane copolymer 2 Eco-solvent 36.78 40.00 36.78 34.78 46.00 50.00 50.00 Silane 1 2.00 3.50 2.00 4.00 4.00 3.50 3.50 Inhibitor 0.08 0.10 0.1 0.1 0.08 0.10 0.10 Resinous Si-H crosslinker 12.04 12.04 12.04 12.04 13.04 5.00 5.00 containing M(H) functions

TABLE-US-00004 TABLE 3a Part A compositions for Examples 8-11 and Comparative examples . 1-3 (wt. %) Ex. 8 Ex. 9 Ex. 10 Ex. 11 C. 1 C. 2 C. 3 Fumed silica LSR master 24.00 9.50 9.50 9.50 10.94 8 8 batch (29.7% silica, 62% low vinyl PDMS polymer) High vinyl PDMS 0.00 4.00 4.00 4.00 5 22.69 22.69 polymer Vinyl-terminated 6.70 15.19 15.19 15.19 21.48 siloxane copolymer 2 Methyl vinyl 0.00 3.95 3.95 3.95 5.3 diol (MVD) Silicone elastomer 16.00 24.00 25.00 24.00 7.02 14.05 14.05 powder ZrAcAc 3.00 3.00 2.00 3.00 0.5 Masterbatch Eco-solvent 50.00 40.00 40.00 40.00 50 55 54.40 Platinum catalyst 0.30 0.36 0.36 0.36 0.26 0.26 0.36 solution

TABLE-US-00005 TABLE 3b Part B compositions for Examples 8-11 and Comparative examples. 1-3 (wt. %) Ex. 8 Ex. 9 Ex. 10 Ex. 11 C. 1 C. 2 C. 3 Fumed silica LSR master batch 37.98 33.36 33.36 33.36 24.31 26.88 26.88 (29.7% silica, 62% low vinyl PDMS polymer) Vinyl-terminated siloxane 3.42 11.00 12.50 11.00 12.57 copolymer 2 Eco-solvent 50.00 40.00 40.00 40.00 50 60 59.60 Silane 1 3.50 2.50 0.4 Silane 2 1.00 2.00 3.50 Inhibitor 0.10 0.10 0.10 0.10 0.08 0.08 0.08 Resinous Si-H crosslinker 12.04 12.04 12.04 13.04 13.04 13.04 containing M(H) functions Trimethylsiloxy terminated Si-H 5.00 cross linker

TABLE-US-00006 TABLE 4a Part A compositions for Comparative examples. 4 to 9 (wt. %) C. 4 C. 5 C. 6 C. 7 C. 8 C. 9 Fumed silica LSR master batch (29.7% 8.45 8.00 10.94 10.94 10.94 10.94 silica, 62% low vinyl PDMS polymer) High vinyl PDMS polymer 3.86 22.69 5.00 5.00 5.00 5.00 Vinyl-terminated 16.5 21.48 21.48 21.48 21.48 siloxane copolymer 2 Methyl vinyl diol (MVD) 4.09 5.30 5.30 5.30 5.30 Silicone elastomer powder 28.59 14.05 7.02 7.02 7.02 7.02 ZrAcAc Masterbatch 2.00 3.00 0.5 4.00 Eco-solvent 36.15 51.90 49.50 46.00 50.00 50.00 Platinum catalyst 0.36 0.36 0.26 0.26 0.26 0.26 solution

TABLE-US-00007 TABLE 4b Part B compositions for Comparative examples. 4 to 9 (wt. %) C. 4 C. 5 C. 6 C. 7 C. 8 C. 9 Fumed silica LSR master 24.31 26.88 24.31 24.31 24.31 24.31 batch (29.7% silica, 62% low vinyl PDMS polymer) Vinyl-terminated 12.57 12.57 12.57 12.57 12.57 siloxane copolymer 2 Eco-solvent 48.00 56.50 49.60 50.00 46.00 46.00 Silane1 3.50 0.4 4.00 Silane 2 4.00 Silane 3 2.00 Inhibitor 0.08 0.08 0.08 0.08 0.08 0.08 Resinous Si-H crosslinker 13.04 13.04 13.04 13.04 13.04 13.04 containing M(H) functions

[0178] Once cured the resulting silicone/polyurethane composite synthetic leather material had a topcoat with an average dry film thickness of between 20 and 25 ?m. Upon inspection it was found that the examples generally exhibited a matting appearance.

[0179] All examples underwent testing for Easy to clean performance and scratch resistance.

[0180] Easy to clean performance was undertaken by marking ball pen on the surface of the cured topcoat of the silicone/polyurethane composite synthetic leather material under test and then checking whether all ball pen marks can be directly cleaned by using tissue paper or medical gauze within 5 minutes. If all ball pen marks can be fully cleaned for more times in same area of one leather sample, this means more excellent easy to clean performance.

[0181] Scratch resistance was carried out in accordance with the FORD FLTM BN 108-13 test Which is designed to determine the resistance to scratching on surfaces of plastic or other materials under standard conditions. In this technique, a scratch testing apparatus is utilised per the test requirements and subsequently an observer uses a controlled light source to visually inspect the presence or absence of a scratch line and rates according to a Rating Scale 1 to 5 (1=no scratch line at all; 5=severe scratch line).

TABLE-US-00008 TABLE 5a Easy to clean and Scratch resistance testing for Examples 1 to 11 Ex. 2, 3, Ex. 6, Ex. Ex. Ex. Ex. 1 4 & 5 7, 8 9 10 11 Repeated easy-to-clean 4 >5 4 >5 5 >5 performance (Times) Scratch resistance test 1~2 1~2 1~2 1~2 1~2 1~2 (silicone coated on surface of PU skin layer)

TABLE-US-00009 TABLE 5b Easy to clean and Scratch resistance testing for Comparative Examples 1 to 9 C. 7, 8 C. 1 C. 2 C. 3 C. 4 C. 5 C. 6 & 9 Repeated 1 0~1 0~1 1 0~1 1~2 0~1 easy-to-clean performance (Times) Scratch 4~5 4~5 3~4 2~3 1~2 3~4 4~5 resistance test (silicone coated on surface of PU skin layer)

[0182] It was noted that after the scratch resistance tests on the comparative examples that some delamination was observed after undergoing the scratching step. This was not observed on the examples. It can be seen from the results the examples in support of the disclosure in Table 5a all had an easy to clean performance of at least 4 whereas the results on the comparatives in Table 5b gave much worse results. Similarly, the scratch resistance results are consistently better with the examples herein. It is believed that the stain resistance (easy to clean) results herein were due to stable bonding between the silicone/polyurethane synthetic leather topcoat composition and the PU skin layer (after the former was cured). One major advantage of the silicone/polyurethane composite synthetic leather material given the high performance shown is the competitiveness of the manufacturing costs (high performance/price ratio) especially compared to pure silicone leather.