Polymer having polyether and polysiloxane segments

Abstract

The invention relates to a polymer having a) a polymer backbone and b) one or more polymeric side chains covalently linked to the polymer backbone, wherein the polymeric side chains comprise a polyether segment and a polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 1050 to 6000, and said polyether segment being positioned between the polymer backbone and the polysiloxane segment.

Claims

1. A polymer having a) a polymer backbone and b) one or more polymeric side chains covalently linked to the polymer backbone, wherein the polymeric side chains comprise a polyether segment and a polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 1050 to 6000, and said polyether segment having a number average molecular weight in the range of 450 to 5000 and being positioned between the polymer backbone and the polysiloxane segment, wherein the polymer has a weight average molecular weight ranging from 4,500 to 15,000.

2. The polymer according to claim 1, wherein the polysiloxane segment has a number average molecular weight in the range of 1100 to 6000.

3. The polymer according to claim 1, wherein the polymer backbone is a (co)polymer of polymerizable ethylenically unsaturated monomers.

4. The polymer according to claim 1, wherein the polyether segment comprises polymerized units of alkylene oxides comprising one or more of ethylene oxide, propylene oxide, and combinations thereof.

5. The polymer according to claim 1, wherein the polymer further comprises functional groups.

6. The polymer according to claim 5, wherein the functional groups comprise one or more of hydroxyl groups, carboxylic acid groups, amino groups, etherified amino groups, amide groups, epoxide groups, alkoxysilyl groups, and combinations thereof.

7. A process for preparing a polymer, the process comprising copolymerizing a) a macromonomer MM having one polymerizable ethylenically unsaturated group, a polyether segment, and a polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 1050 to 6000, and said polyether segment having a number average molecular weight in the range of 450 to 5000 and being positioned between the polymerizable ethylenically unsaturated group and the polysiloxane segment, and b) at least one other further monomer having at least one polymerizable ethylenically unsaturated group, the resulting polymer comprising a backbone and one or more polymeric side chains covalently linked to the polymer backbone, wherein the polymeric side chains comprise a polyether segment and a polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 1050 to 6000, said polyether segment being positioned between the polymer backbone and the polysiloxane segment, and the resulting polymer having a weight average molecular weight ranging from 4,500 to 15,000.

8. The process according to claim 7, wherein the macromonomer MM is prepared by i) providing a) a monomer having one polymerizable ethylenically unsaturated group and one further functional group which is different from the polymerizable ethylenically unsaturated group, and b) a molecule having a group which is reactive towards said at least one further functional group, a polyether segment, and a polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 1050 to 6000, and said polyether segment being positioned between said group which is reactive towards said at least of further functional group and the polysiloxane segment, ii) forming a covalent bond between the monomer a) and the molecule b) by reacting the at least one further functional group with the group which is reactive towards said at least one further functional group.

9. The process according to claim 7, wherein the macromonomer MM is prepared by i) providing a) a monomer having one polymerizable ethylenically unsaturated group, a polyether segment, and one further ethylenically unsaturated functional group which is different from the polymerizable ethylenically unsaturated group, and wherein the polyether segment is located between the polymerizable ethylenically unsaturated group and the further ethylenically unsaturated functional group, b) a molecule having a polysiloxane segment having a number average molecular weight in the range of 1050 to 6000 and one Si—H group, and ii) forming a covalent bond between the monomer a) and the molecule b) by a hydrosylilation reaction of the Si—H group on the further ethylenically unsaturated functional group.

10. A process for preparing a polymer, comprising the steps of: i) providing a) a polymer backbone having at least one functional group and b) a molecule having a group which is reactive towards said at least one functional group, a polyether segment, and a polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 1050 to 6000, and said polyether segment being positioned between said group which is reactive towards said at least one functional group and the polysiloxane segment, and ii) forming a covalent bond between the polymer backbone a) and the molecule b) by reacting the at least one functional group with the group which is reactive towards said at least one functional group, the resulting polymer comprising a backbone and one or more polymeric side chains covalently linked to the polymer backbone, wherein the polymeric side chains comprise a polyether segment and a polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 1050 to 6000, and said polyether segment having a number average molecular weight in the range of 450 to 5000 and being positioned between the polymer backbone and the polysiloxane segment, and the resulting polymer having a weight average molecular weight ranging from 4,500 to 15,000.

11. The process of claim 10, the resulting polymer having a weight average molecular weight ranging from 3,500 to 75,000.

12. A composition comprising a) a polymer in an amout of 0.1 to 15% by weight, based on the total non-volatile content of the composition, the polymer having a polymer backbone and one or more polymeric side chains covalently linked to the polymer backbone, wherein the polymeric side chains comprise a polyether segment and a polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 1050 to 6000, and said polyether segment being positioned between the polymer backbone and the polysiloxane segment, and b) a binder, which is different from said polymer a).

13. The composition according to claim 12, wherein the composition is liquid at a temperature of 20° C. and comprises a volatile diluent.

14. A multilayer coating system on a substrate comprising at least one undercoat layer and a one top-coat layer, wherein at least one layer is based on a composition according to claim 12.

15. The multilayer coating system according to claim 14, wherein the substrate is a motor vehicle or a part thereof.

16. The composition of claim 12, the polyether segment having a number average molecular weight in the range of 450 to 5000.

17. A process of forming a multilayer coating system on a substrate comprising the steps of i) applying a coating composition a) to a substrate to form a coating layer a) and ii) applying a coating composition b) to form a coating layer b) on top of coating layer a), wherein at least one of the coating composition a) or the coating composition b) comprises a polymer in an amount of 0.1 to 15% by weight, based on the total non-volatile content of the coating composition, the polymer having a polymer backbone and one or more polymeric side chains covalently linked to the polymer backbone, wherein the polymeric side chains comprise a polyether segment and a polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 1050 to 6000, and said polyether segment being positioned between the polymer backbone and the polysiloxane segment.

18. The process of claim 17, the polyether segment having a number average molecular weight in the range of 450 to 5000.

Description

EXAMPLES

(1) Raw materials:

(2) TABLE-US-00001 THF Tetrahydrofuran (Aldrich) Shellsol A Mixture of aromatics, boiling range 148.9-182.2° C. (manufacturer: Royal Dutch Shell) Bisomer MPEG550MA methoxy polyethylene glycol 550 methacrylate (manufacturer: Cognis/BASF) AAE450MA α-allyl-ω-methacryloxy functional polyether, iodine number 87.3 g I.sub.2/g (manufacturer: GEO Specialty Chemicals UK Ltd) EHA 2-ethylhexyl acrylate (manufacturer: Evonik) Trigonox 21 tert-butyl peroxy-2-ethylhexanoate (manufacturer: Akzo Nobel) Setamine US 138 BB-70 Partly butylated melamine in n-butanol (manufacturer: Allnex) Setalux 1760 VB-64 thermoplastic styrene acrylic in solvent naphtha/butanol (manufacturer: Allnex) Setalux 91760 SS-53 acrylic based resin in Solvent naphtha/ n-Butanol/propylene glycol (manufacturer: Allnex) Setamine US 138 BB-70 amino resin (melamine, butylated) in n-butyl acetate (manufacturer: Allnex) Tinuvin 292 liquid hindered amine light stabilizer (manufacturer: BASF) Tinuvin 1130 liquid UV absorber of the hydroxyphenyl benzotriazole class (manufacturer: BASF)

(3) GPC-analysis of the prepared macromonomers and copolymers

(4) The number-average and weight-average molecular weights and the molecular weight distribution were determined according to DIN 55672-1:2007-08 at 40° C. using a high-pressure liquid chromatography pump (WATERS 600 HPLC pump) and a refractive index detector (Waters 410). A combination of 3 Styragel columns from WATERS with a size of 300 mm×7:8 mm ID/column, a particle size of 5 μm and pore sizes HR4, HR2 and HR1 was used as separating columns. The eluent used for the copolymers was tetrahydrofuran with 1% by volume of dibutylamine with an elution rate of 1 ml/min. The conventional calibration was carried out using polystyrene standards.

(5) For the Polydimethylsiloxane (PDMS) macromers the eluent was toluene with an elution rate of 1 ml/min. The conventional calibration was carried out using polydimethylsiloxane standards. Molecular weights reported and referred to in this document always have the unit g/mol.

(6) Iodine Number

(7) The Si—H group-content of the Si—H-functional PDMS macromonomers SM1 to SM4 and the Si—H-conversion during the hydrosilylation reaction for the preparation of the PDMS-Polyether block-copolymers was determined according to DIN 53241-1 via volumetric measurement of H.sub.2.

(8) OH Number

(9) The hydroxyl group-content of the OH-functional PDMS-Polyether block-copolymers and the OH-conversion during the trans-esterification reaction for the preparation of the PDMS-Polyether block-macromonomers was determined according to DIN ISO 4629.

(10) Non-Volatile Content

(11) The amount of non-volatile matter (solids content) is determined via DIN EN ISO 3251:2008-06 at 150° C. for 20 min.

(12) General procedure for the preparation of SiH-functional polysiloxane segments A four-necked flask provided with stirrer, thermometer, dropping funnel and nitrogen inlet tube is heated to 150° C. under nitrogen flow using a heat gun to remove traces of water. After cooling of the apparatus to ambient temperature under nitrogen flow, the vessel is charged with a solution hexamethylcyclotrisiloxane (D3) in cyclohexane, which has been dried over molecular sieve A3 for 24 h. At a reaction temperature of 20° C., butyllithium solution (1.7M in hexane) was introduced over a period of 5 min. The reaction mixture was not allowed to exceed 30° C. by cooling with a water bath. After 30 min, THF was slowly added to start the polymerization reaction. The temperature was monitored and kept below 30° C. After 5 h, the reaction was quenched by the addition of dimethylchlorosilane and stirred for additional 30 min. Afterwards, the mixture was neutralized by the addition of a sodium bicarbonate solution in water (8.0 wt %) and vigorously stirred for 1 h. The organic layer was separated, distilled in vacuum (20 mbar at 100° C.) to remove all solvents, and filtered through a plug of Celite. The product (unsymmetrical, SiH-functional polydimethylsiloxane) is a clear, colorless liquid of low viscosity.

(13) TABLE-US-00002 TABLE 1 Overview of SiH-functional polysiloxane segments PSS prepared PSS1 PSS2 PSS3 PSS4 PSS5 Raw materials in g D3 887.4 1843.3 2888.5 4883.4 9883.6 Cyclohexane 712.3 1479.6 2318.8 3919.9 7933.5 Butyllithium solution 277.3 277.3 277.3 277.3 277.3 (1.7M in hexane) THF 712.3 1479.6 2318.8 3919.9 7933.5 Dimethylchlorosilane 109.6 109.6 109.6 109.6 109.6 Sodium 161.8 161.8 161.8 161.8 161.8 Biocarbonate solution 8 wt % in water Analytical data Iodine number 25.3 12.7 8.5 5.1 2.5 M.sub.n 968 1870 2937 4954 10300 M.sub.w/M.sub.n 1.1 1.2 1.2 1.1 1.1

(14) General procedure for the preparation of macromonomers MM having a polyether segment, a polysiloxane segment, and a polymerizable ethylenically unsaturated group

(15) A four-necked flask equipped with stirrer, thermometer, dropping funnel and nitrogen inlet tube is charged with the α-allyl-ω-methacryloxy-functional polyether, which is used in an molar excess of 25% with respect to the SiH-functional polysiloxane, the SiH-functional polysiloxane segment PSS, and ethyl acetate. The components are mixed and heated to 40° C. At that temperature 0.6 g catalyst (2% wt Karstedt's catalyst in Xylene) are added. The temperature is then increased to 60° C.

(16) The conversion of SiH was monitored via Iodine number. It usually took between 1.5 and 2.5 hours to reach complete consumption of all SiH functions. After that the reaction mixture was cooled to ambient temperature and filtered through a cellulose filter paper, 2,6-Di-tert-butyl-4-methylphenol and 4-Methoxyphenol (each 0.026 g) were added to stabilize the product.

(17) The macromonomers were obtained as clear, yellow and slightly viscous liquids.

(18) TABLE-US-00003 TABLE 2 Overview of macromonomers MM prepared Raw materials in g MM1 MM2 MM3 MM4 MM5 PSS1 150.0 PSS2 200.0 PSS3 200.1 PSS4 150.0 PSS5 130.0 AAE450MA 108.3 71.9 51.3 23.0 9.3 M.sub.n 1394 1959 3105 5234 10511 M.sub.w/M.sub.n 1.3 1.3 1.3 1.3 1.3

(19) Preparation of the inventive copolymers A1 to A6 and comparative copolymers B1 to B3

(20) In a beaker, the monomer mixture as per Table 3, including the initial amount of radical initiator Trigonox 21, is prepared and diluted with 30% of the total amount of Isobutanol mentioned in Table 3. This monomer mixture is transferred into a dropping funnel. A four-necked flask provided with stirrer, thermometer and a nitrogen inlet tube is charged with the remaining amount of Isobutanol and heated to 110° C. The dropping funnel with the monomer mixture is mounted on the reaction vessel and nitrogen is passed through the reaction apparatus for 10 min. After the reaction temperature is reached the monomer mixture is slowly metered in over a period of 90 minutes. Thereafter, the reaction temperature is maintained at 110° C. for 60 minutes, before 0.1 g Trigonox 21 is added. The reaction temperature is maintained at 110° C. for another 60 minutes before the solvent used is removed by distillation under vacuum on a rotary evaporator (20 mbar, 120° C.),

(21) TABLE-US-00004 TABLE 3 Raw material amounts (in g) and analytical data for the synthesis of inventive double-comb-block copolymers A1 to A7 and comparative copolymers B1, B2, and B3 B1 A1 A2 A3 A4 A5 A6 B2 B3 Isobutanol 64.6 65.6 64.6 65.8 64.6 66.1 64.6 66.3 64.6 MM1 6.7 MM2 5.4 6.7 MM3 5.0 6.7 MM4 4.6 6.7 MM5 4.4 6.7 EHA 31.4 31.9 31.4 32.0 31.4 32.2 31.4 32.2 31.4 MPEG550MA 60.1 61.0 60.1 61.3 60.1 61.5 60.1 61.7 60.1 Trigonox 21 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 Non-volatile 99.6 99.5 99.8 99.4 99.8 99.7 99.7 99.7 99.7 matter in % wt M.sub.n 5690 5835 5852 5842 5771 5653 5851 5847 5650 M.sub.w/M.sub.n 2.3 2.4 2.4 2.3 2.4 2.3 2.4 2.4 2.3

(22) Application test in a solvent-borne clear coat

(23) Preparation of a solvent-borne clearcoat SC1

(24) The preparation of the solvent-borne clear coat is separated into several steps for better clarity. The steps are:

(25) a) Preparation of the liquid formulation

(26) b) Application, curing and evaluation

(27) Preparation of the liquid formulation of a solvent-borne clear coat SC1

(28) TABLE-US-00005 TABLE 4 Raw materials for the solvent-borne clear coat Raw materials Amount in g Setalux 1760 VB 64 33.4 Setalux C 91760 SS 53 26.2 Setamine US 138 BB 70 21.2 BYK 306 0.05 BYK 331 0.1 Tinuvin 292 0.5 Tinuvin 1130 0.75 n-Butanol 2.2 Shellsol A 3.5 Xylene 12.1 Surface additives as per Table 5 0.1, 0.3 and 0.7% wt on total formulation

(29) All components as per Table 4 were separately loaded and subsequently stirred in a PE beaker using a Dispermat CV equipped with a dissolver disc 50 mm at 1000 rpm for 20 min. After storing the formulation overnight at room temperature, the inventive surface additives and comparative examples as per Table 5, were added. Three concentrations (0.1% wt, 0.3% wt and 0.7% wt on total formulation) of the surface additives were evaluated.

(30) Application, curing and evaluation in a solvent-borne clear coat SC1

(31) The modified clear coat formulations were adjusted to 27 sec DIN 4 cup application viscosity by Shellsol A/Xylene (1:1) and applied on panel (coil-coat primered metal panels+waterborne base coat) by hand application. Afterwards, the panels were dried for 10 min at ambient temperature and then cured for 20 min at 140′C in a stoving oven. Dry film thickness approx. 30-40 μm. The surface slip (CoF=coefficient of friction) was measured by Altek equipment. The surface energy and contact angle of water were determined on the coated and cured panels using a Krüss G2 instrument. A low contact angle of water improves the wetting of next layer. In addition, the absence of craters in this application is crucial.

(32) TABLE-US-00006 TABLE 5 Contact angle of water and leveling performance in a solvent-borne clear coat SC1 Dosage in Surface energy in mN/m Contact angle Additive wt % on solid CoF crater total disperse polar H.sub.2O in .sup.° control 0.53 0 26.8 21.0 5.8 82 B1 0.1 0.23 0 27.4 19.3 8.1 77 0.3 0.14 0 29 0 18 5 10.3 72 0.7 0.16 0 31.3 16.2 15.1 64 A1 0.1 0.14 0 26.8 18.8 8.0 78 0.3 0.08 0 28.4 17.0 12.4 71 0.7 0.08 0 32.0 15.6 16.4 63 A2 0.1 0.12 0 27.4 18.4 9.0 76 0.3 0.06 1 29.3 16.4 12.9 69 0.7 0.08 0 32.8 15.4 17.4 62 A3 0.1 0.13 0 27.3 18.1 9.2 75 0.3 0.06 0 27.7 17.2 10.4 73 0.7 0.07 0 30.6 15.5 15.5 66 A4 0.1 0.13 0 26.3 18.6 7.7 78 0.3 0.06 0 28.8 16.5 12.2 70 0.7 0.06 0 31.0 15.5 15.5 65 A5 0.1 0.22 0 24.8 19.7 5.1 84 0.3 0.06 0 25.6 18.8 6.8 81 0.7 0.04 0 27.8 17.6 10.2 74 A6 0.1 0.10 0 24.8 20.4 4.4 86 0.3 0.04 0 25.7 19.0 6.7 81 0.7 0.04 0 27.8 17.8 10.0 76 B2 0.1 0.32 0 26.1 21.7 4.4 86 0.3 0.18 0 27.3 20.5 6.6 81 0.7 0.11 0 27.1 19.2 7.9 78 B3 0.1 0.32 0 26.3 22.0 4.3 87 0.3 0.17 0 27.0 20.6 6.4 81 0.7 0.16 0 26.7 19.2 7.5 79

(33) From Table 5 it can be inferred that the polymers of the invention effectively decrease the coefficient of friction when included in a coating composition in small amounts, in particular more effectively than the comparative polymers B1, B2, and B3. The coefficient of friction is lowered more effectively than with the comparative polymers. A low coefficient of friction means that the coatings exhibit improved surface slip. This is achieved without negative effect on cratering.

(34) Furthermore, with the polymers of the invention the surface energy is on a sufficiently high level, and the contact angle of water is sufficiently low. Both properties indicate good overcoatabilty. However, when the Mn of the polysiloxane segment in the polymer is outside the range of the present invention, these properties deteriorate.

(35) Application test in a water-borne medium oil alkyd emulsion

(36) Preparation of the liquid formulation

(37) 50 g of a waterborne medium oil alkyd emulsion (free of additives) was placed in a PE beaker and slowly stirred using a Dispermat CV equipped with a dissolver disc 30 mm at room temperature.

(38) The amount of additive listed in table 6 was added and stirring at 2000 rpm was continued for 2 minutes. After storing the formulations overnight at room temperature a 150 μm bar film applicator (commercially available at BYK-Gardner GmbH, Lausitzer Str, 8, 82538 Geretsried) was used to apply the first coating layer of the respective formulation on a byko-chart (also commercially available at BYK-Gardner GmbH). The remaining liquid coating formulation material was sealed and stored overnight at room temperature. The respective byko-charts with the first layers were dried horizontally overnight at room temperature.

(39) On the next day a second layer of the same liquid coating formulation (as used for the first layer) was applied onto the first layer using a 150 μm bar film applicator. After complete horizontal drying of the two-layer System, the appearance of the respective system was evaluated visually.

(40) Application test results (anti-cissing)

(41) The results are listed in following table.

(42) TABLE-US-00007 TABLE 6 Additive Dosage in weight-% None strong cissing B1 0.5 cissing A1 0.5 no cissing A2 0.5 no cissing A3 0.5 no cissing A4 0.5 no cissing A5 0.5 no cissing A6 0.5 no cissing B2 0.5 cissing B3 0.5 cissing

(43) The inventive polymers improve the performance of the coating system by preventing cissing.