PROCESS TO PREPARE AQUEOUS POLYURETHANE DISPERSIONS IN WHICH THE POLYURETHANE INCLUDES POLYSILOXANE AS SIDE CHAIN

Abstract

A process for the preparation of an aqueous polysiloxane-polyurethane dispersion wherein the polysiloxane is present as a side chain of the polyurethane resin and which are useful as part of the coating of a flexible sheet-like substrate.

Claims

1. A process for the preparation of an aqueous polydialkylsiloxane-polyurethane dispersion wherein the polydialkylsiloxane is present as a side chain of the polyurethane resin, comprising the steps of: i) synthesizing a polyurethane prepolymer from isocyanates, polyols, that include polyols with hydrophilic groups and/or polyols that have an additional functional group that is capable of forming a salt, and a polydialkylsiloxane component A, said component A having 2 hydroxyl groups attached to an alkyl group on one end of the linear polydialkylsiloxane chain and an alkyl group on the other end of the linear polydialkylsiloxane chain; and ii) dispersing the obtained prepolymer into a water phase (iii) adding one or more neutralizing agents prior to, simultaneously with or after dispersing the prepolymer in water, (iv) forming polyurethane by reacting with one or more extension agents simultaneously with or subsequent to the dispersing.

2. The process according to claim 1, wherein component A has a molecular weight of above about 1000 Dalton

3. The process according to claim 1, wherein component A has a molecular weight of about 5000 Dalton or more.

4. The process according to claim 1, wherein component A is a mono-dicarbinol terminated polydialkylsiloxane.

5. The process according to claim 1, wherein component A is a mono-dicarbinol terminated polydimethylsiloxane, of which the alkyl diol chain has between 1 and about 10 carbon atoms and of which the polydialkylsiloxane chain has more than about 25 dialkylsiloxane repetitive units.

6. The process according to claim 1, wherein between about 0.1 weight % and about 25 weight %, of component A, compared to total weight of the polyol and isocyanate components in the prepolymer, is used.

7. The process according to claim 1, wherein between about 0.3 weight % and 20 weight %, of component A, compared to total weight of the polyol and isocyanate components in the prepolymer, is used.

8. The process according to claim 1, wherein between about 2 weight % and 15 weight % of component A, compared to total weight of the polyol and isocyanate components in the prepolymer, is used.

9. The process according to claim 1, wherein the component A is reacted simultaneously with all the other reactive components in the prepolymer or is reacted first with (part of) the isocyanate components, prior to the reaction with other isocyanate-reactive components.

10. The process according to claim 1, wherein the isocyanates are selected from aliphatic di-isocyanates, aromatic di-isocyanates, or a mixture of aromatic and aliphatic di-isocyanates, such as toluene-2,4-diisocyanate, toluene-2,6-diisocyanate and mixtures thereof, diphenylmethane-4,4-diisocyanate, 1,4-phenylenediisocyanate, dicyclohexyl-methane-4,4′-diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclo-hexylisocyanate, 1,6-hexyldi-isocyanate, 1,5-pentyldiisocyanate, 1,3-bis(isocyanatomethyl)cyclo-hexane, 2,2,4-trimethyl-1,6-diisocyanatohexane (2,2,4-isomer, 2,4,4-isomer, or mixture thereof), 1,4-cyclohexyldiiso-cyanate, norbonyldiisocyanate, p-xylylene diisocyanate, 2,4′-diphenylmethane diisocyanate, and/or 1,5-naphthylene diisocyanate.

11. The process according to claim 1, wherein the polyols are selected from polyester polyols, polyesteramide polyols, polyether polyols, polythioether polyols, polycarbonate polyols, polyacetal polyols, polyolefin polyols or mixtures thereof.

12. The process according to claim 1, wherein the polyols are selected from diols or triols with molecular weight below about 500.

13. The process according to claim 1, wherein polyols with hydrophilic groups or polyols that have an additional functional group that is capable of forming a salt, are selected from polyethoxy diol, a poly(ethoxy/-propoxy) diol, a diol containing a pendant ethoxy or (ethoxy/propoxy) chain, a diol containing a carboxylic acid, a diol containing a sulfonic group, a diol containing a phosphate group, a polyethoxy mono-ol, a poly(ethoxy/-propoxy) mono-ol, a mono-ol containing a pendant ethoxy or (ethoxy/propoxy) chain, a mono-ol containing a carboxylic acid or a sulfonic acid or salt, or mixtures thereof.

14. The process according to claim 1, wherein the extension agent is a selected from polyol, water, an amino alcohol, ammonia, a primary or secondary aliphatic, alicyclic, aromatic, araliphatic or heterocyclic amine especially a diamine, hydrazine or a substituted hydrazine, or a mixture thereof.

15. The process according to claim 1, wherein the extension agent is a water-soluble extension agent.

16. The process according to claim 1, wherein the neutralising agent is selected from a tertiary amines such as tripropylamine, dimethyl butyl amine, dimethyl ethanol amine, diethyl ethanol amine, triethylamine, 2-amino-2-methyl-1-propanol and N-ethylmorpholine, or an alkaline metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide or non-volatile tertiary amines such as N-butyldiethanolamine or N,N-bis[3-(dimethylamino)propyl]-N′,N′-dimethylpropane-1,3-diamine or mixtures thereof.

17. The process according to claim 1, wherein the prepolymer may contain between about 0% and 35 weight %.

18. The process according to claim 1, wherein a solids content of the aqueous polyurethane dispersion is at least 25 weight %, preferably at least 30 weight %.

19. A dispersion obtainable by the process of claim 1.

20. A coating or film obtained from a dispersion according to claim 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

Examples

Example 1: Preparation of Polyurethane Dispersion

[0043] Under a nitrogen atmosphere a mixture of 15 g of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate and 150 g of X-22-176F (a mono-dicarbinol terminated polydimethylsiloxane from Shin-Etsu Chemical Company; molecular weight 12500 Dalton) together with 0.05 g of K-Kat 348 (from King Industries) as catalyst were reacted with each other for one hour at 70° C. The reaction was cooled down and the amount of remaining NCO was measured.

[0044] Under a nitrogen atmosphere a mixture 220 g of a polycarbonate diol, derived from hexanediol, with a molecular weight of 2000, 120 g of dipropylene glycol dimethyl ether and 15 g of dimethylolpropanoic acid were heated to 50° C. while stirring. 75 g of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate and 15 g of the reaction product of the afore-mentioned 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate and X-22-176F, together with 0.05 g of K-Kat 348 (from King Industries) as catalyst, were added and the mixture was heated to 85° C. and stirred for 2 hours to form a polyurethane prepolymer. The reaction was cooled down and the amount of remaining NCO was measured. A mixture was made of 195 g of the prepolymer and 5 g of triethylamine, and this mixture was dispersed into a water phase consisting of 225 g of water, 5 g of Provichem 2588P (a 50% solution of sodium dioctyl sulfosuccinate in dipropylene glycol dimethyl ether, from Proviron Functional Chemicals NV) and 2 g of hydrazine hydrate. The dispersion was stirred for an additional 15 minutes. The solids content of the dispersion was 30%. The viscosity of the dispersion was 70 mPa.Math.s, as measured at 25° C. using a Brookfield LVF Viscometer. Of the total solids content of the dispersion, 4 weight % comes from the mono-dicarbinol terminated polydimethylsiloxane.

Example 2: Preparation of Polyurethane Dispersion

[0045] Under a nitrogen atmosphere a mixture 240 g of a polycarbonate diol, derived from hexanediol, with a molecular weight of 2000, 140 g of dipropylene glycol dimethyl ether, 7 g of X-22-176F (a mono-dicarbinol terminated polydimethylsiloxane from Shin-Etsu Chemical Company; molecular weight 12500 Dalton) and 15 g of dimethylolpropanoic acid were heated to 50° C. while stirring. 100 g of dicyclohexyl-methane-4,4′-diisocyanate together with 0.05 g of K-Kat 348 (from King Industries) as catalyst were added and the mixture was heated to 100° C. and stirred for 2 hours to form a polyurethane prepolymer. The reaction was cooled down and the amount of remaining NCO was measured. A mixture was made of 190 g of the prepolymer and 4 g of triethylamine, and this mixture was dispersed into a water phase consisting of 230 g of water, 4 g of Provichem 2588P (a 50% solution of sodium dioctyl sulfosuccinate in dipropylene glycol dimethyl ether, from Proviron Functional Chemicals NV) and 2 g of hydrazine hydrate. The dispersion was stirred for an additional 15 minutes. The solids content of the dispersion was 30%. The viscosity of the dispersion was 100 mPa.Math.s, as measured at 25° C. using a Brookfield LVF Viscometer. Of the total solids content of the dispersion, 2 weight % comes from the mono-dicarbinol terminated polydimethylsiloxane.

Example 3: Preparation of Polyurethane Dispersion

[0046] Under a nitrogen atmosphere a mixture 190 g of a polycarbonate diol, derived from hexanediol, with a molecular weight of 2000, 80 g of dipropylene glycol dimethyl ether, 40 g of X-22-176F (a mono-dicarbinol terminated polydimethylsiloxane from Shin-Etsu Chemical Company; molecular weight 12500 Dalton) and 15 g of dimethylolpropanoic acid were heated to 50° C. while stirring. 75 g of 3-isocyanatomethyl-3,5,5-trimethylcyclo-hexylisocyanate together with 0.05 g of K-Kat 348 (from King Industries) as catalyst were added and the mixture was heated to 95° C. and stirred for 2 hours to form a polyurethane prepolymer. The reaction was cooled down and the amount of remaining NCO was measured. A mixture was made of 125 g of the prepolymer and 3 g of triethylamine, and this mixture was dispersed into a water phase consisting of 215 g of water, 4 g of Provichem 2588P (a 50% solution of sodium dioctyl sulfosuccinate in dipropylene glycol dimethyl ether, from Proviron Functional Chemicals NV) and 2 g of hydrazine hydrate. The dispersion was stirred for an additional 15 minutes. The solids content of the dispersion was 30%. The dispersion was filtered over 100 μm filter. The viscosity of the dispersion was 60 mPa.Math.s, as measured at 25° C. using a Brookfield LVF Viscometer. Of the total solids content of the dispersion, 12 weight % comes from the mono-dicarbinol terminated polydimethylsiloxane.

Example 4: Preparation of Polyurethane Dispersion

[0047] Under a nitrogen atmosphere a mixture of 36 g of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate and 64 g of X-22-176DX (a mono-dicarbinol terminated polydimethylsiloxane from Shin-Etsu Chemical Company; molecular weight 3000 Dalton) together with 0.05 g of K-Kat 348 (from King Industries) as catalyst were reacted with each other for one hour at 70° C. The reaction was cooled down and the amount of remaining NCO was measured.

[0048] Under a nitrogen atmosphere a mixture 195 g of a polycarbonate diol, derived from hexanediol, with a molecular weight of 2000, 110 g of dipropylene glycol dimethyl ether and 13 g of dimethylolpropanoic acid were heated to 50° C. while stirring. 65 g of 3-isocyanatomethyl-3,5,5-trimethylcyclo-hexylisocyanate and 18 g of the reaction product of the afore-mentioned 3-isocyanatomethyl-3,5,5-trimethylcyclo-hexylisocyanate and X-22-176DX, together with 0.05 g of K-Kat 348 (from King Industries) as catalyst, were added and the mixture was heated to 90° C. and stirred for 1 hours to form a polyurethane prepolymer. The reaction was cooled down and the amount of remaining NCO was measured. A mixture was made of 170 g of the prepolymer and 4 g of triethylamine, and this mixture was dispersed into a water phase consisting of 200 g of water, 4 g of Provichem 2588P (a 50% solution of sodium dioctyl sulfosuccinate in dipropylene glycol dimethyl ether, from Proviron Functional Chemicals NV) and 2 g of hydrazine hydrate. The dispersion was stirred for an additional 15 minutes. The solids content of the dispersion was 30%. The viscosity of the dispersion was 80 mPa.Math.s, as measured at 25° C. using a Brookfield LVF Viscometer. Of the total solids content of the dispersion, 4 weight % comes from the mono-dicarbinol terminated polydimethylsiloxane.

Example 5: Comparative Polyurethane Dispersion

[0049] Under a nitrogen atmosphere 390 g of a polycarbonate diol, derived from hexanediol, with a molecular weight of 2000, 220 g of dipropylene glycol dimethyl ether and 23 g of dimethylolpropanoic acid were heated to 70° C. while stirring. 165 g of dicyclohexyl-methane-4,4′-diisocyanate together with 0.05 g of K-Kat 348 (from King Industries) as catalyst was added and the mixture was heated to 95° C. and stirred for 2 hours to form a polyurethane prepolymer. The reaction was cooled down and the amount of remaining NCO was measured. A mixture was made of 405 g of the prepolymer and 7 g of triethylamine, and this mixture was dispersed into a water phase consisting of 575 g of water, 4 g of Aerosol OT-75 (from Cytec Industries) and 6 g of hydrazine hydrate. The dispersion was stirred for an additional 15 minutes. The solids content of the dispersion was 30%. The viscosity of the dispersion was 25 mPa.Math.s, as measured at 25° C. using a Brookfield LVF Viscometer.

Example 6: Comparative Polyurethane Dispersion

[0050] Under a nitrogen atmosphere a mixture of 22 g of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate and 78 g of Fluid OH 40 D (a linear dicarbinol terminated polydimethylsiloxane from Wacker Chemie AG; molecular weight 3000 Dalton) together with 0.05 g of K-Kat 348 (from King Industries) as catalyst were reacted with each other for one hour at 70° C. The reaction was cooled down and the amount of remaining NCO was measured.

[0051] Under a nitrogen atmosphere 220 g of a polycarbonate diol, derived from hexanediol, with a molecular weight of 2000, 120 g of dipropylene glycol dimethyl ether and 15 g of dimethylolpropanoic acid were heated to 70° C. while stirring. 165 g of dicyclohexyl-methane-4,4′-diisocyanate and 17 g of the reaction product of the afore-mentioned 3-isocyanatomethyl-3,5,5-trimethylcyclo-hexylisocyanate and Fluid OH 40 D, together with 0.05 g of K-Kat 348 (from King Industries) as catalyst was added and the mixture was heated to 90° C. and stirred for 2 hours to form a polyurethane prepolymer. The reaction was cooled down and the amount of remaining NCO was measured. A mixture was made of 185 g of the prepolymer and 4 g of triethylamine, and this mixture was dispersed into a water phase consisting of 225 g of water, 5 g of Provichem 2588P (a 50% solution of sodium dioctyl sulfosuccinate in dipropylene glycol dimethyl ether, from Proviron Functional Chemicals NV) and 2 g of hydrazine hydrate. The dispersion was stirred for an additional 15 minutes. The solids content of the dispersion was 30%. The viscosity of the dispersion was 300 mPa.Math.s, as measured at 25° C. using a Brookfield LVF Viscometer. Of the total solids content of the dispersion, 4 weight % comes from the linear dicarbinol terminated polydimethylsiloxane.

Example 7: Evaluative Tests

[0052] Anti-soiling tests were performed on films made on release paper, on a Martin-Dale apparatus following ISO 26082-1:2012 method, with soiling cloth according to ISO 12947-1 size, using Daimler-104 cloth and 200 cycles. The degree of soiling was determined by measuring the coloration by a colour computer. Coloration is expressed in ΔE values, where a higher value indicates more darkening, with a lower value being best, and in Gray-scale, where the scale is from 1 to 5, with 5 being best.

[0053] Taber Abrasion resistance was tested on films made on vinyl as substrate, following ISO 17076-1:2012 method, using H18 wheel, 500 g load and 200 cycles. The extent of abrasion was measured by weight loss, where a lower weight loss is best.

[0054] Water repellence was measured according to AATCC TM 193, which determines resistance to wetting by aqueous liquids. Drops of water-alcohol mixtures of varying surface tensions were placed on the surface of a dried film on release, and the extent of surface wetting was determined visually on a scale from 0 to 8, with 8 indicating the highest water repellence.

TABLE-US-00001 Anti-soiling Anti-soiling Taber abrasion Water Example ΔE Grey-scale Weight loss (mg) repellence Example 1 0.20 4.88 88 4 Example 2 0.75 4.26 80 6 Example 3 0.62 4.64 75 6 Example 4 0.19 4.89 79 6 Comparative 7.86 1.79 69 6 Example 5 Comparative 0.88 4.49 69 6 Example 6

[0055] The comparative example 5 gave a strong coloration after the soiling test, as is demonstrated by the large ΔE value and low value in the grey-scale. The inventive examples 1 to 4 gave a much lower ΔE value and much higher value in the grey-scale. This demonstrates that the anti-soiling is much improved by the incorporation of mono-dicarbinol terminated polydimethylsiloxane into the polyurethane of the aqueous polyurethane dispersion.

[0056] The Taber abrasion of the inventive examples 1 to 4 was only little higher than of the comparative example 5, demonstrating that the abrasion is almost not altered by the incorporation of mono-dicarbinol terminated polydimethylsiloxane into the polyurethane of the aqueous polyurethane dispersion.

[0057] The water repellence test results demonstrate that the water repellence is increased compared to comparative example 5, by the incorporation of mono-dicarbinol terminated polydimethylsiloxane into the polyurethane of the aqueous polyurethane dispersion.

[0058] Of the total solids content of the dispersion from Comparative Example 6, 4 weight % comes from the linear dicarbinol terminated polydimethylsiloxane, which has a molecular weight of 3000 Dalton. Of the total solids content of the dispersion from Example 4, 4 weight % comes from the mono-dicarbinol terminated polydimethylsiloxane, which has a molecular weight of 3000 Dalton. The result in the anti-soiling test of Example 4 is better than of Comparative Example 6. Of the total solids content of the dispersion from Example 2, 2 weight % comes from the mono-dicarbinol terminated polydimethylsiloxane, which has a molecular weight of 125000 Dalton. The result in the anti-soiling test of Example 2 is similar as of Comparative Example 6, whereas Example 2 contains half the weight % of polydimethylsiloxane component.

[0059] The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

[0060] Note that in the specification and claims, “about” or “approximately” means within twenty percent (20%) of the numerical amount cited. The term “a”, “an”, and “the” means one or more unless otherwise specified.

[0061] Although the invention has been described in detail with particular reference to these embodiments, other embodiments can achieve the same results. Variations and modifications of embodiment of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference.