Thermosetting powder coating compositions having lower chalk-free temperature

Patent metadata

Field	Value
Publication number	US-11535758-B2
Application number	US-201716336675-A
Country	US
Kind code	B2
Filing date	Sep 27, 2017
Priority date	Sep 28, 2016
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

Thermosetting powder coating compositions and processes for making the thermosetting powder coating compositions and processes for coating an article with the thermosetting powder coating compositions are disclosed. Cured thermosetting powder coating compositions are obtained by curing of the thermosetting powder coating compositions of the invention. Articles are provided having coated thereon the thermosetting powder coating compositions as well as to articles having coated and cured thereon the thermosetting powder coating compositions. The thermosetting powder coating compositions exhibit a substantially lower Tchalk-free, that is a ΔTchalk-free which is in the range of from and including 5 up to and not including 10° C., wherein ΔTchalk-free=Tchalk-freeREF−Tchalk-freeA where Tchalk-freeA is the Tchalk-free of a thermosetting powder coating composition according to the invention (TPCC-A) and Tchalk-freeREF is the Tchalk-free of a thermosetting powder coating composition not according to the invention (TPCC-REF) that is comparable to TPCC-A.

First claim

The invention claimed is:

1. A thermosetting powder coating composition comprising the following components A to E:
A: one or more unsaturated resins comprising ethylenic unsaturations (UR) selected from the group consisting of polyester resins, polyurethanes, epoxy resins, polyamides, polyesteramides, polycarbonates, polyureas and mixtures thereof, and
B: one or more curing agents selected from the group consisting of vinyl urethanes, vinyl functionalized urethane resins and mixtures thereof, wherein at least one of the one or more curing agents is curing agent A which is selected from the group consisting of i), ii) and iii):
i) one or more crystalline VU-c each of which is a crystalline vinyl urethane having a melting enthalpy ΔH m ≥35 J/g, and
ii) one or more crystalline VFUR-c each of which is a crystalline vinyl functionalized urethane resin having a melting enthalpy ΔH m ≥35 J/g, and
iii) mixtures of the one or more crystalline VU-c and the one or more crystalline VFUR-c, wherein
the ΔH m is each measured via Differential Scanning Calorimetry (DSC) according to the description, and
a ratio K of the total mol of the ethylenic unsaturations in B divided by the total mol of the ethylenic unsaturations in A is at least 0.9 and at most 7,

C: one or more thermal radical initiators selected from the group consisting of organic peroxides, azo compounds, and mixtures thereof, wherein the total amount of component C is at least 25 and at most 300 mmol/Kg A and B, and
D: one or more co-initiators selected from the group consisting of onium compounds, sulpho-compounds, and mixtures thereof, wherein
(D1) the onium compound is selected from the group consisting of compounds represented by formulae I-X through IX-X below:

wherein
A − is a halide anion;
R 1 ′″ is a C 1 -C 12 saturated hydrocarbyl,
R 2 ′″ is a C 1 -C 12 saturated hydrocarbyl;
R 3 ′″ is H or a C 1 -C 12 hydrocarbyl,
R 4 ′″ is a C 1 -C 12 hydrocarbyl;
R 5 ′″ is H or a C 1 -C 12 hydrocarbyl,
R 6 ′″ is a C 1 -C 12 hydrocarbyl;
R 7 ′″ is H or a C 1 -C 12 hydrocarbyl,
R 8 ′″ is H or a C 1 -C 12 hydrocarbyl;
R 9 ′″ is H or a C 1 -C 12 hydrocarbyl,
R 10 ′″ is H or a C 1 -C 12 hydrocarbyl,
R 11 ′″ is H or a C 1 -C 12 hydrocarbyl, and
R 12 ′″ is H or a C 1 -C 12 hydrocarbyl, and wherein

(D2) the sulpho-compound is selected from the group consisting of sulpho-compounds-1, sulpho-compounds-2, sulpho-compounds-3, sulpho-compounds-4, sulpho-compounds-5, and mixtures thereof, wherein
the sulpho-compound-1 is a compound represented by the following formula L1:

wherein R 1 ′ is a C 1 -C 10 hydrocarbyl, and R 2 ′ is a C 1 -C 10 hydrocarbyl, and wherein
the sulpho-compound-2 is a compound represented by the following formula L2:

wherein R 3 ′ is a C 1 -C 12 hydrocarbyl, and R 4 ′ is a C 1 -C 12 hydrocarbyl, and wherein
the sulpho-compound-3 is a compound represented by the following formula L3:

wherein R 5 ′ is a C 1 -C 12 hydrocarbyl, and R 6 ′ is a C 1 -C 12 hydrocarbyl and R 7 ′ is a C 1 -C 12 saturated hydrocarbyl, and R 8 ′ is a C 1 -C 12 saturated hydrocarbyl, and wherein
the sulpho-compound-4 is a compound represented by the following formula L4:

wherein R 9 ′ is a C 1 -C 12 hydrocarbyl, and R 10 ′ is a C 1 -C 12 hydrocarbyl and R 11 ′ is a C 1 -C 12 hydrocarbyl, and wherein
the sulpho-compound-5 is a compound represented by the following formula L5:

wherein R 12 ′ is a C 1 -C 12 hydrocarbyl or a substituted hydrocarbyl, and R 13 ′ is a C 1 -C 12 hydrocarbylene, and wherein

the total amount of component D is at least 10 and at most 150 mmol/Kg A and B, and

E: one or more inhibitors selected from the group consisting of phenolic compounds, stable radicals, catechols, phenothiazines, hydroquinones, benzoquinones and mixtures thereof, and wherein the component E is present in a total amount which is at least 20 and at most 2000 mg/Kg of the components A and B.

2. The thermosetting powder coating composition according to claim 1 , wherein the onium compound is selected from the group consisting of compounds represented by the formula I-X, compounds represented by the formula II-X, compounds represented by the formula V-X, compounds represented by the formula VI-X, and compounds represented by the formula VII-X, and wherein
the sulpho-compound is selected from the group consisting of the sulpho-compound-1, the sulpho-compound-2, the sulpho-compound-3, the sulpho-compound-4 and the sulpho-compound-5.

3. The thermosetting powder coating composition according to claim 1 , wherein the component D is one or more co-initiators selected from the group consisting of bis(4-dodecylphenyl)iodonium chloride, bis(4-dodecylphenyl)iodonium iodide, bis(4-tert-butylphenyl)iodonium chloride, bis(4-tert-butylphenyl)iodonium iodide, (4-methylphenyl)(4-(2-methylpropyl)phenyl)iodonium chloride, (4-methylphenyl)(4-(2-methylpropyl)phenyl)iodonium iodide, diphenyliodonium chloride, diphenyliodonium iodide, 2-(((tert-butylsulfonyl)(diazo)methyl)sulfonyl)-2-methylpropane, tert-butyl 4-methylbenzenesulfonate, 2-isopropyl-5-methylcyclohexyl 4-methylbenzenesulfonate, 2-methyl-2-[(4-methylphenyl)sulfonyl]-1-[4-(methylthio)phenyl]-1-propanone, and mixtures thereof.

4. The thermosetting powder coating composition according to claim 1 , wherein the component B is present in an amount of at least 14 and at most 55 pph of the components A and B.

5. The thermosetting powder coating composition according to claim 1 , wherein the curing agent A is present in an amount of at least 98 pph of the component B.

6. The thermosetting powder coating composition according to claim 1 , wherein the total amount of the component C is at most 95 mmol/Kg of the components A and B.

7. The thermosetting powder coating composition according to claim 1 , wherein the component C is selected from the group consisting of organic peroxides and mixtures thereof.

8. The thermosetting powder coating composition according to claim 1 , wherein the component C is selected from the group consisting of peranhydrides, peroxydicarbonates and mixtures thereof.

9. The thermosetting powder coating composition according to claim 1 , wherein the UR is an unsaturated polyester resin comprising 2-butenedioic acid ethylenic unsaturations.

10. The thermosetting powder coating composition according to claim 1 , wherein the UR has:
a) a number average molecular weight (M n ) of at least 1000 and at most 10000 Da, and
b) a glass transition temperature (T g ) of at least 40 and at most 75° C., and
c) a weight pe

Assignees

• Covestro Netherlands Bv

Inventors

• Bongaerts Johannes Gertrudis Christianus

Classifications

• C08G18/671 Primary

  Unsaturated compounds having only one group containing active hydrogen (takes precedence on groups C08G18/675 - C08G18/69) · CPC title

• C08G2150/20

  Compositions for powder coatings · CPC title

• C08K5/13

  Phenols; Phenolates · CPC title

• C09D167/06

  Unsaturated polyesters having carbon-to-carbon unsaturation · CPC title

• C09D169/00

  Coating compositions based on polycarbonates; Coating compositions based on derivatives of polycarbonates · CPC title