Ladder copolymer

Abstract

The invention relates to a polymer comprising a) at least two polymer backbone chains and b) at least one polymeric connecting chain comprising at least two polyether segments and one polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 400 to 6000 g/mol, and at least one of the at least two polyether segments being positioned between the polymer backbone chains and the polysiloxane segment, wherein the at least two polymer backbone chains are linked by the at least one polymeric connection chain.

Claims

1. A polymer comprising a) at least two polymer backbone chains and b) at least one polymeric connecting chain comprising at least two polyether segments and one polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 400 to 6000 g/mol, and at least one of the at least two polyether segments being positioned between the at least two polymer backbone chains and the polysiloxane segment, wherein the at least two polymer backbone chains are linked by the at least one polymeric connection chain, and wherein the polymer has a weight average molecular weight in the range of 2000 to 200000 g/mol, determined via GPC using polystyrene standards and tetrahydrofuran as eluent.

2. The polymer according to claim 1, wherein at least one of the at least two polymer backbone chains has at least one pendant polymer chain comprising at least two polyether segments and one polysiloxane segment, said polysiloxane segment of the at least one pendant polymer chain having a number average molecular weight in the range of 400 to 6000 g/mol, and at least one of the at least two polyether segments of the at least one pendant polymer chain being positioned between the at least one of the at least two polymer backbone chains and the polysiloxane segment of the at least one pendant polymer chain.

3. The polymer according to claim 1, wherein the polysiloxane segment has a number average molecular weight in the range of 900 to 4000 g/mol.

4. The polymer according to claim 1, wherein the at least two polymer backbone chains are (co) polymers of polymerizable ethylenically unsaturated monomers.

5. The polymer according to claim 1, wherein the at least two polyether segments, independent of each other, have a number average molecular weight in the range of 88 to 3000 g/mol.

6. The polymer according to claim 1, wherein the at least two polyether segments comprise polymerized units of one or more of ethylene oxide and propylene oxide.

7. The polymer according to claim 1, wherein the polymer further comprises at least one of a hydroxyl group, a carboxylic acid group, an amino group, an etherified amino group, an amide group, an epoxide group, and an alkoxysilyl group.

8. A process for preparing a polymer, the process comprising polymerizing a monomer mixture comprising a) a polyether-modified polysiloxane having at least two polyether segments and at least two polymerizable ethylenically unsaturated groups attached to at least two of the at least two polyether segments, and one polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 400 to 6000 g/mol, and said polysiloxane segment being positioned between the at least two polyether segments, and b) at least one other further monomer having one polymerizable ethylenically unsaturated group, the polymer comprising a) at least two polymer backbone chains and b) at least one polymeric connecting chain comprising at least two polyether segments and one polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 400 to 6000 g/mol, and at least one of the at least two polyether segments being positioned between the at least two polymer backbone chains and the polysiloxane segment, wherein the at least two polymer backbone chains are linked by the at least one polymeric connection chain, and wherein the polymer has a weight average molecular weight in the range of 2000 to 200000 g/mol, determined via GPC using polystyrene standards and tetrahydrofuran as eluent, and wherein the at least two polymer backbone chains are (co) polymers of polymerizable ethylenically unsaturated monomers.

9. The process according to claim 8, wherein the monomer mixture further comprises a second polyether-modified polysiloxane having at least two polyether segments and one polymerizable ethylenically unsaturated group attached to one of the at least two polyether segments, and one polysiloxane segment, said polysiloxane segment of said second polyether-modified polysiloxane having a number average molecular weight in the range of 400 to 6000 g/mol, and being positioned between the at least two polyether segments.

10. A composition comprising a) the polymer according to claim 1 in an amount of 0.01 to 15.00% by weight, based on the total non-volatile content of the composition, and b) a binder, which is different from said polymer a).

11. The composition according to claim 10, wherein the composition is liquid at a temperature of 20 C. and comprises a volatile diluent.

12. A multilayer coating system on a substrate comprising at least one undercoat layer and at least one top-coat layer, wherein at least one layer of the multilayer coating system is formed from a composition according to claim 10.

13. The multilayer coating system according to claim 12, wherein the substrate is a motor vehicle or a part thereof.

14. 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 coating composition a) or coating composition b) comprises a polymer in an amount of 0.01 to 15.00% by weight, based on the total non-volatile content of the coating composition, wherein the polymer comprises a) at least two polymer backbone chains and b) at least one polymeric connecting chain comprising at least two polyether segments and one polysiloxane segment, said polysiloxane segment having a number average molecular weight in the range of 400 to 6000 g/mol, and at least one of the at least two polyether segments being positioned between the at least two polymer backbone chains and the polysiloxane segment, wherein the at least two polymer backbone chains are linked by the at least one polymeric connection chain, and wherein the polymer has a weight average molecular weight in the range of 2000 to 200000 g/mol, determined via GPC using polystyrene standards and tetrahydrofuran as eluent.

15. A composition comprising a binder and an additive, the additive comprising the polymer according to claim 1.

Description

EXAMPLES

(1) Raw Materials:

(2) Isobutanol (iBuOH) was used as solvent for all polymerizations.

(3) TABLE-US-00001 description EHA 2-ethylhexyl acrylate BA Butyl acrylate HEMA Hydroxyethyl methacrylate -MSD -methylstyrene dimer Silicone divinyl terminated polydimethylsiloxane having a viscosity of approx. component 1 20 mm.sup.2/s at 25 C. Silicone polyether-modified polydimethylsiloxane having the theoretical component 2 structure of M.sup.RD.sub.24M.sup.R and R = (CH.sub.2).sub.3-EO.sub.11/PO.sub.4OH Silicone Acryloxy functional polyether-modified polydimethylsiloxane with a component 3 silicone compound having the theoretical structure of M.sup.RD.sub.24M.sup.R and R = (CH.sub.2).sub.3-EO.sub.11/PO.sub.4OH and whereas approx. 40% of the hydroxyl groups have been acrylated. Silicone Acryloxy functional polyether-modified polydimethylsiloxane with a component 4 silicone compound having the theoretical structure of M.sup.RD.sub.24M.sup.R and R = (CH.sub.2).sub.3-EO.sub.11/PO.sub.4OH and whereas approx. 80% of the hydroxyl groups have been acrylated. AMBN Azobisisobutyronitrile

(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 mm7.8 mm ID/column, a particle size of 5 m and pore sizes HR4, HR2 and HR1 was used as separating columns. The eluent used for the copolymers was tetrahydrofuran filtered through a 0.2 m membrane filter with an elution rate of 1 ml/min. The conventional calibration was carried out using Polystyrene standards. Molecular weights reported and referred to in this document always have the unit g/mol.

(5) General Procedure for the Preparation of Comparative Examples C1 and C2

(6) The required amounts of solvent and monomers are specified in Table 1. In a 4-necked round glass flask connected to a reflux condenser, a temperature sensor, a N.sub.2 gas inlet and a dropping funnel, isobutanol was heated to reflux (approx. 107 C.) under a constant N.sub.2 gas flow. The monomers and azobisisobutyronitrile as the initiator (4 parts) were homogenized and metered into the reaction mixture at a uniform rate over a period of 3 hours. After the end of the addition the reaction temperature was maintained at refluxing conditions for 0.5 h. Thereafter, two times azobisisobutyronitrile (0.1 parts) were added at 1 h intervals. After stirring the reaction mixture under refluxing conditions for 1 h, the reaction mixture was cooled to ambient conditions. The product was characterized by gel permeation chromatography and the M.sub.W was determined (Table 1).

(7) Procedure for the Preparation of Comparative Example C3

(8) In a 4-necked round glass flask connected to a reflux condenser, a temperature sensor, a N.sub.2 gas inlet and a dropping funnel, 34.7 parts isobutanol were heated to reflux (approx. 107 C.) under a constant N.sub.2 gas flow. 24 parts 2-ethylhexyl acrylate, 23 parts butyl acrylate, 10.2 parts hydroxyethyl methacrylate and azobisisobutyronitrile as the radical initiator (4 parts) were homogenized and metered into the reaction mixture at a uniform rate over a period of 3 hours. After the end of the addition the reaction temperature was maintained at refluxing conditions for 0.5 h. Thereafter, two times azobisisobutyronitrile (0.1 parts) were added at 1 h intervals. After stirring the reaction mixture under refluxing conditions for 1 h, the reaction mixture was cooled to ambient conditions. 4 parts of silicone component 2 were added and the mixture homogenized 5 min. The product was characterized by gel permeation chromatography (M.sub.W=5595 g/mol).

(9) General Procedure for the Preparation of Inventive Examples E1 to E3

(10) The required amounts of solvent and monomers are specified in Table 1. In a 4-necked round glass flask connected to a reflux condenser, a temperature sensor, a N.sub.2 gas inlet and a dropping funnel, isobutanol was heated to reflux (approx. 107 C.) under a constant N.sub.2 gas flow. The monomers, chain transfer agent (optionally) and azobisisobutyronitrile as the initiator (4 parts) were homogenized and metered into the reaction mixture at a uniform rate over a period of 3 hours. After the end of the addition the reaction temperature was maintained at refluxing conditions for 0.5 h. Thereafter, two times azobisisobutyronitrile (0.1 parts) were added at 1 h intervals. After stirring the reaction mixture under refluxing conditions for 1 h, the reaction mixture was cooled to ambient conditions. The product was characterized by gel permeation chromatography and the M.sub.W was determined (Table 1).

(11) TABLE-US-00002 TABLE 1 Composition of examples C1-C2 and E1- E3, amounts are in parts by weight Silicone component Mw Ex. iBuOH EHA BA HEMA -MSD # amount [g/mol] C1 34.6 25.5 24.5 11.2 5605 C2 34.7 24.5 23.5 10.2 1 3.1 5882 C3 34.7 24.0 23.0 10.2 2 4.0 5595 E1 34.7 24.5 23.5 10.2 3 3.1 6105 E2 34.0 24.0 23.0 10.0 2.0 3 3.0 6145 E3 34.0 24.0 23.0 10.0 2.0 4 3.0 6434

(12) The preparation of the solvent-borne clear coat is separated into several steps for better clarity. The steps are: a) Preparation of the liquid formulation b) Application, curing and evaluation
Preparation of the Liquid Formulation of a Solvent-Borne Clear Coat

(13) TABLE-US-00003 TABLE 2 Parts by Binder component Description weight Synthalat A 086 HS Polyacrylate polyol ex Synthopol 82.1 Butyl acetate Solvent 8.0 Xylene Solvent 7.4 2-Butoxyethyl acetate Solvent 1.4 BYK-052 N Defoamer ex BYK-Chemie GmbH 0.5 Crosslinker component Desmodur N 3390 Trimer of hexamethylene 20.3 diisocyanate es Covestro Butyl acetate Solvent 29.7

(14) The ingredients indicated in Table 2 were mixed and homogenized to form a binder component and a crosslinker component.

(15) The binder component was subsequently separated into portions one polymer of the invention or of comparative polymer was added and mixed in. The amount of added polymer was 0.3% by weight of added polymer, calculated on the binder component.

(16) Clear coat compositions were prepared by mixing the binder components with the crosslinker component in a ratio of 2:1 by weight.

(17) Application, Curing and Evaluation

(18) The clear coat compositions were applied to steel panels with a spiral film applicator in a wet film thickness of 50 m. The applied clear coats were allowed to dry and cure for 24 hours at room temperature.

(19) The coefficient of friction (COF) was determined with an Altek measurement device using a weight of 500 g and self-adhesive felt. The readings of the instrument were multiplied by a factor of 0.02.

(20) Overcoatability was tested by applying second clear coat layer on the cured clear coats described above. The second clear coat layer contained no polymer of the invention or comparative polymer. The flow and leveling of the second clear coat layer were judged on a scale of 1 (very good) to 5 (poor). The leveling of the first layer was determined using a wavescan apparatus ex BYK-Gardner. The long-wave (LVV) and short-wave (SW) values were recorded.

(21) Crater formation of each layer was judged visually on a scale from 1 (no craters) to 5 (severe crater formation).

(22) Haze of each coating layer was judged visually on a scale of 1 (no haze) to 5 (sever haze).

(23) The cross-cut adhesion test was carried out according to DIN EN ISO 2404. The results are reported on a scale of 1 (no delamination) to 5 (severe delamination).

(24) The results are summarized in Table 3.

(25) TABLE-US-00004 Surface tension of Coefficient Leveling of first Cross-cut Added first layer of friction of layer (Wavescan) Leveling of adhesion of polymer (in mN/m) first layer SW LW crater second layer second layer none 25.6 0.44 20.5 11.3 5 5 1 C1 25.6 0.44 33.8 32.5 5 5 1 C2 26.1 0.28 14.3 17.2 3 4 2 C3 24.6 0.32 11.2 20.0 1 3 5 E1 26.5 0.36 11.9 16.9 1 3 1 E2 25.0 0.37 10.4 15.0 1 2 1

(26) From Table 3 it can be concluded that comparative polymer C1 without silicone has no beneficial effect at all. Comparative polymer C2 according to US 2019/0144588 A has a positive effect on levelling. However, the amount of crater formation is unsatisfactory. Also, levelling of the second layer and cross-cut adhesion are not satisfactory. Comparative polymer C3 leads to poor cross-cut adhesion of the second layer.

(27) The polymer according to the invention E1 and E2 show very good overall balance of improved properties, in particular good leveling, no crater formation, and good adhesion of the second layer.

(28) A further series of tests was carried out with clear coats applied by airless spraying to primed steel panels. The wet film layer thickness was 80 m. Leveling was determined by the Wavescan apparatus. Short-wave and long-wave readings were recorded.

(29) The results are summarized in Table 4.

(30) TABLE-US-00005 Leveling by Wavescan Added polymer LW SW C1 n.m. n.m. C2 10.7 26.8 E1 5.4 3.2 E2 11.4 6.7 E3 1.8 4.5

(31) Comparative polymer C1 without silicone provided a surface with very poor leveling that was not measurable using the Wavescan apparatus. Comparative polymer C2 has a positive effect on leveling but is unsatisfactory in the short-wave measurement.

(32) Polymers E1, E2, and E3 according to the invention lead to an overall improved leveling.