POLYMER COMPOSITIONS FOR THERMAL SPRAY COATING

Abstract

The present invention relates to a polymer composition for use in thermal spray coating application comprising an -olefin homopolymer or copolymer, a functionalized a-olefin homopolymer or copolymer, a polyolefinic elastomer and an anti-corrosion additive. Such polymer compositions have a good long-term corrosion resistance, good coating to substrate adhesion, good long-term adhesion and good long-term weather resistance.

Claims

1.-9. (canceled)

10. Thermal spray coating powder comprising powder particles which comprise a polymer composition comprising a. an -olefin homopolymer or copolymer; b. a functionalized -olefin homopolymer or copolymer; c. a polyolefinic elastomer; and d. an anti-corrosion additive; wherein the powder particles have an average particle size D.sub.50 as measured according to ISO-13320 of between 100 and 600 m.

11. (canceled)

12. Coating comprising one or more layers comprising a polymer composition comprising a. an -olefin homopolymer or copolymer; b. a functionalized -olefin homopolymer or copolymer; c. a polyolefinic elastomer; and d. an anti-corrosion additive.

13. A thermal spray coating process comprising: applying a coating powder to a substrate, the coating powder comprising powder particles which comprise a polymer composition comprising a. an -olefin homopolymer or copolymer; b. a functionalized -olefin homopolymer or copolymer; c. a polyolefinic elastomer; and d. an anti-corrosion additive: wherein the powder particles have an average particle size D.sub.50 as measured according to ISO-13320 of between 100 and 600 m.

14. The process according to claim 13 in which the substrate is one or more selected from steel, concrete, cast iron, fiberglass, thermoset resins, and/or wood.

15. The process according to claim 13 further comprising preheating the substrate.

16. The process according to claim 15, wherein substrate is preheated to a temperature of to a temperature of at least 80 C.

17. The process according to claim 13, wherein the coating powder is applied to the substrate via a thermal spray gun.

18. The process according to claim 13, wherein the coating has a coating to substrate adhesion of greater than 8 MPa.

19. The process according to claim 13 in which the polymer composition comprises 1-10 wt % functionalized -olefin homopolymer or copolymers.

20. The process according to claim 13 in which the polymer composition comprises 0.5-15 wt % polyolefinic elastomers.

21. The process according to claim 13 in which the polymer composition comprises 1.0-30 wt % anti-corrosion additives.

22. The process according to claim 13 in which the composition comprises: a) 60.0-95.0 wt % of an -olefin homopolymer or copolymer; b) 1.0-5 wt % of a functionalized -olefin homopolymer or copolymer; c) 2.0-15 wt % of a polyolefinic elastomer; and d) 2.0-15 wt % of an anti-corrosion additive; with regard to the total weight of the polymer composition.

23. The process according to claim 13 in which the -olefin homopolymer or copolymer is selected from a propylene homopolymer, a propylene copolymer, a low density polyethylene, a linear low density polyethylene, or a high density polyethylene.

24. The process according to claim 13 in which the functionalized -olefin homopolymer or copolymer has a functional moiety that is present as part of the main polymer chain or of one of more of the side chains, as a moiety grafted onto the polymer, or as a functional end group terminating the main polymer chain or one or more of the side chains, in which said functional moiety is one or more selected from a hydroxyl functional moiety, an amine functional moiety, an acrylic or methacrylic acid functional moiety, a cyclic acid anhydride functional moiety, a siloxy functional moiety or an amino-silane functional moiety.

25. The process according to claim 13 in which the polyolefinic elastomer is a copolymer of ethylene and at least one -olefin containing 3 to 8 carbon atoms, having a density of between 855 kg/m.sup.3 and 920 kg/m.sup.3 as measured according to ISO 1183 and having a melt index of between 0.5 and 40 g/10 min as measured according to ISO 1133 at a temperature of 190 C. and a load of 2.16 kg.

26. The process according to claim 13 in which the anti-corrosion additive is zinc phosphate.

27. A coated substrate comprising: a substrate; and a coating disposed on the substrate, the coating comprising one or more layers comprising a polymer composition, which comprises a. an -olefin homopolymer or copolymer; b. a functionalized -olefin homopolymer or copolymer; c. a polyolefinic elastomer; and d. an anti-corrosion additive.

28. The coated substrate of claim 27, wherein the substrate is steel, concrete, cast iron, fiberglass, thermoset resins, and/or wood.

Description

EXPERIMENTS

[0134] In a 25 mm twin screw extruder, operated at 190, polymer compositions were prepared using the ingredients in quantities as listed in table 1.

TABLE-US-00001 TABLE 1 Example 1 2 3 4 C1 C2 C3 LDPE 86.81 81.81 86.81 81.81 92.03 99.56 100 Antioxidant 0.19 0.19 0.19 0.19 0.18 0.19 Light stabilizer 0.25 0.25 0.25 0.25 0.24 0.25 Polyolefin elastomer 5.00 5.00 5.00 5.00 4.87 Functionalized 2.75 2.75 2.75 2.75 2.68 polyethylene Anti-corrosion additive 5.00 10.00 5.00 10.00

[0135] The values in table 1 present weight fractions in % of the total composition.

[0136] As antioxidant, a blend of Irganox B225, a product obtainable from BASF was used. Irganox B225 is a blend containing 50 wt % Irganox 1010 (tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxymethyl)methane) and 50 wt % Irgafos 168 (tris(2,4-di-tert-butylphenyl) phosphite).

[0137] As light stabilizer, Chimassorb 944, (poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]]), a product obtainable from BASF was used.

[0138] As an a-olefin homopolymer or copolymer, a linear low-density polyethylene, also referred to as LDPE, having a melt index as measured according to as measured according to ISO 1133 at a temperature of 190 C. and a load of 2.16 kg of 22 g/10 min, and having a density as measured according to ISO 1183 of 922 kg/m.sup.3.

[0139] As polyolefin elastomer, Engage 8400, an ethylene-octene based polyolefin elastomer product obtainable from Dow Chemical was used.

[0140] As a functionalized a-olefin homopolymer or copolymer, Polybond 3029, obtainable from Addivant, was used.

[0141] As anti-corrosion additive, zinc phosphate was used. In examples 1 and 2, the zinc phosphate that was used is ZPLEX 111, a compound comprising 10-25 wt % of zinc phosphate, obtainable from Halox. In examples 3 and 4, ZPLEX 250, a zinc phosphate, obtainable from Halox, was used.

TABLE-US-00002 TABLE 2 Example 1 2 3 4 C1 C2 C3 Ingression of corrosion (mm) 13 11 16 13 48 Coating to substrate adhesion (MPa) CF CF CF CF 0.8 Long-term adhesion (cycles) NF NF NF NF 8 3 2 Weather resistance (weeks) NF NF NF NF NF NF 2

[0142] In examples 1-4 according to the present invention, cohesive failure occurred, as indicated by CF in Table 2. This demonstrates that the coating to substrate adhesion exceeds the cohesive strength of the material itself.

[0143] In examples 1-4 according to the present invention no failure was observed on sample plaques that were subjected to the long-term adhesion testing. This is indicated in the table by NF.

[0144] In examples 1-4 according to the present invention and comparative examples C1 and C2, no failure was observed on sample plaques that were subjected to the long-term weather resistance testing in the Weather-O-Meter. This is indicated in the table by NF.

[0145] From the examples as presented above, it becomes evident that compositions according to the present invention show good long-term corrosion resistance, good coating to substrate adhesion, good long-term adhesion and good long-term weather resistance.