CN115521447A - 50/50 fast curing type polyester resin for low-gloss powder coating and preparation method thereof - Google Patents
50/50 fast curing type polyester resin for low-gloss powder coating and preparation method thereof Download PDFInfo
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- CN115521447A CN115521447A CN202211414831.4A CN202211414831A CN115521447A CN 115521447 A CN115521447 A CN 115521447A CN 202211414831 A CN202211414831 A CN 202211414831A CN 115521447 A CN115521447 A CN 115521447A
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- 238000000576 coating method Methods 0.000 title claims abstract description 55
- 229920001225 polyester resin Polymers 0.000 title claims abstract description 53
- 239000004645 polyester resin Substances 0.000 title claims abstract description 53
- 239000011248 coating agent Substances 0.000 title claims abstract description 41
- 239000000843 powder Substances 0.000 title claims abstract description 36
- 238000002360 preparation method Methods 0.000 title description 10
- 239000002994 raw material Substances 0.000 claims abstract description 22
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 claims abstract description 18
- GHLKSLMMWAKNBM-UHFFFAOYSA-N dodecane-1,12-diol Chemical compound OCCCCCCCCCCCCO GHLKSLMMWAKNBM-UHFFFAOYSA-N 0.000 claims abstract description 18
- SILNNFMWIMZVEQ-UHFFFAOYSA-N 1,3-dihydrobenzimidazol-2-one Chemical compound C1=CC=C2NC(O)=NC2=C1 SILNNFMWIMZVEQ-UHFFFAOYSA-N 0.000 claims abstract description 12
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 claims abstract description 9
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims abstract description 9
- SLCVBVWXLSEKPL-UHFFFAOYSA-N neopentyl glycol Chemical compound OCC(C)(C)CO SLCVBVWXLSEKPL-UHFFFAOYSA-N 0.000 claims abstract description 9
- HIJQFTSZBHDYKW-UHFFFAOYSA-N 4,4-dimethyloxane-2,6-dione Chemical compound CC1(C)CC(=O)OC(=O)C1 HIJQFTSZBHDYKW-UHFFFAOYSA-N 0.000 claims abstract description 8
- FWHUTKPMCKSUCV-UHFFFAOYSA-N 1,3-dioxo-3a,4,5,6,7,7a-hexahydro-2-benzofuran-5-carboxylic acid Chemical compound C1C(C(=O)O)CCC2C(=O)OC(=O)C12 FWHUTKPMCKSUCV-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000002253 acid Substances 0.000 claims description 26
- 238000010438 heat treatment Methods 0.000 claims description 26
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 19
- 239000003963 antioxidant agent Substances 0.000 claims description 17
- 230000003078 antioxidant effect Effects 0.000 claims description 17
- 238000006243 chemical reaction Methods 0.000 claims description 17
- 238000006116 polymerization reaction Methods 0.000 claims description 14
- 239000003054 catalyst Substances 0.000 claims description 12
- 229920000642 polymer Polymers 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 12
- YHWCPXVTRSHPNY-UHFFFAOYSA-N butan-1-olate;titanium(4+) Chemical group [Ti+4].CCCC[O-].CCCC[O-].CCCC[O-].CCCC[O-] YHWCPXVTRSHPNY-UHFFFAOYSA-N 0.000 claims description 11
- 238000004321 preservation Methods 0.000 claims description 9
- 239000000376 reactant Substances 0.000 claims description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- 238000005886 esterification reaction Methods 0.000 claims description 8
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 8
- 238000005070 sampling Methods 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 239000002904 solvent Substances 0.000 claims description 5
- 229910000831 Steel Inorganic materials 0.000 claims description 4
- 150000008064 anhydrides Chemical class 0.000 claims description 4
- 238000009835 boiling Methods 0.000 claims description 4
- 239000007806 chemical reaction intermediate Substances 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 4
- 230000032050 esterification Effects 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 238000006068 polycondensation reaction Methods 0.000 claims description 4
- 239000010959 steel Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 3
- 239000007858 starting material Substances 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 14
- 239000003822 epoxy resin Substances 0.000 abstract description 8
- 229920000647 polyepoxide Polymers 0.000 abstract description 8
- 238000007712 rapid solidification Methods 0.000 abstract description 4
- 238000007711 solidification Methods 0.000 abstract description 4
- 230000008023 solidification Effects 0.000 abstract description 4
- 125000002883 imidazolyl group Chemical group 0.000 abstract description 3
- 239000012467 final product Substances 0.000 abstract description 2
- 230000000379 polymerizing effect Effects 0.000 abstract description 2
- 239000000047 product Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 6
- SSDSCDGVMJFTEQ-UHFFFAOYSA-N octadecyl 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate Chemical group CCCCCCCCCCCCCCCCCCOC(=O)CCC1=CC(C(C)(C)C)=C(O)C(C(C)(C)C)=C1 SSDSCDGVMJFTEQ-UHFFFAOYSA-N 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 5
- 239000011812 mixed powder Substances 0.000 description 5
- 239000002245 particle Substances 0.000 description 4
- 239000003973 paint Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 239000008096 xylene Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 2
- ISAOCJYIOMOJEB-UHFFFAOYSA-N benzoin Chemical compound C=1C=CC=CC=1C(O)C(=O)C1=CC=CC=C1 ISAOCJYIOMOJEB-UHFFFAOYSA-N 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 239000000543 intermediate Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 244000028419 Styrax benzoin Species 0.000 description 1
- 235000000126 Styrax benzoin Nutrition 0.000 description 1
- 235000008411 Sumatra benzointree Nutrition 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229960002130 benzoin Drugs 0.000 description 1
- 230000008033 biological extinction Effects 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- MNUSMUGFHGAOIW-UHFFFAOYSA-N cyclohexane-1,1,2-tricarboxylic acid Chemical compound OC(=O)C1CCCCC1(C(O)=O)C(O)=O MNUSMUGFHGAOIW-UHFFFAOYSA-N 0.000 description 1
- WTNDADANUZETTI-UHFFFAOYSA-N cyclohexane-1,2,4-tricarboxylic acid Chemical compound OC(=O)C1CCC(C(O)=O)C(C(O)=O)C1 WTNDADANUZETTI-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 235000019382 gum benzoic Nutrition 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 238000011027 product recovery Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000012719 thermal polymerization Methods 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 239000002966 varnish Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/68—Polyesters containing atoms other than carbon, hydrogen and oxygen
- C08G63/685—Polyesters containing atoms other than carbon, hydrogen and oxygen containing nitrogen
- C08G63/6854—Polyesters containing atoms other than carbon, hydrogen and oxygen containing nitrogen derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/6856—Dicarboxylic acids and dihydroxy compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
- C09D167/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/03—Powdery paints
- C09D5/032—Powdery paints characterised by a special effect of the produced film, e.g. wrinkle, pearlescence, matt finish
Abstract
The invention relates to a 50/50 fast curing polyester resin for low-gloss powder coating, which is obtained by polymerizing terephthalic acid, neopentyl glycol, 1, 12-dodecanediol, triethanolamine, 1,2, 4-cyclohexane tricarboxylic anhydride, 2-hydroxybenzimidazole, 3-dimethyl glutaric anhydride and the like serving as raw materials; the finally obtained polyester resin has soft chain segment and lower softening point, except that the long chain carboxyl introduced with 3, 3-dimethyl glutaric anhydride can be solidified with E-12 epoxy resin, the polyester resin realizes low-temperature rapid solidification by introducing an imidazole group with ultra-high activity, the final product has high solidification speed with the E-12 epoxy resin, can realize low-temperature rapid solidification film forming at 160 ℃/8min, and has higher leveling grade; meanwhile, the carboxyl and the imidazoline amino participate in curing at the same time, so that the self-extinction effect is realized by the difference of the curing speed, the gloss of a coating film can reach 20-30%, and the coating film has an excellent decorative effect.
Description
Technical Field
The invention relates to the field of powder coatings, in particular to a 50/50 fast curing type polyester resin for a low-gloss powder coating and a preparation method thereof.
Background
The powder coating has the advantages of no solvent volatilization, easy product recovery and the like, and gradually replaces paint to develop widely in the coating industry, such as decorative powder coating of indoor furniture, outdoor weather-resistant powder coating and the like, the indoor mixed powder coating mainly comprises polyester and E-12 epoxy resin as main film forming resin, the maximum using amount is 50/50 mixed powder coating system, such as the powder coating is used in the fields of indoor refrigerators, air conditioners, cabinets and the like, because the curing of the powder coating needs to be carried out for sufficient film forming at a high temperature (generally above 180 ℃) for 180 ℃/15min or 200 ℃/10min and the like, and along with the rising of energy price, the energy consumption cost of downstream customers is increased. It is important to develop polyester resin products that can be cured sufficiently rapidly in a short time. Meanwhile, the indoor decorative coating generally needs to be subjected to flatting treatment for the sake of attractiveness, a common method is to add a flatting agent for flatting, and due to the addition of the flatting agent, the phenomena of large gloss difference caused by uneven mixing and obvious poor flatting are easy to occur. Aiming at the problem that how to realize low-temperature short-time quick curing of 50/50 mixed powder coating with the largest indoor using amount to achieve the purpose of energy saving, realize self extinction without adding a delustering agent, and overcome the defect of adding the delustering agent is an urgent need in the industry.
In order to solve the problems, the polyester resin is obtained by polymerization by using terephthalic acid, neopentyl glycol, 1, 12-dodecanediol, triethanolamine, 1,2, 4-cyclohexane tricarboxylic acid anhydride, 2-hydroxybenzimidazole, 3-dimethyl glutaric anhydride and the like as raw materials based on the design of a chain segment structure and a polyester resin with a high active end curing group; the finally obtained polyester resin and the E-12 epoxy resin are high in curing speed, can be rapidly cured at a low temperature to form a film, is high in leveling grade, achieves an excellent self-extinction effect, can achieve 20-26% of film gloss, and finally has an excellent decorative effect.
Disclosure of Invention
A50/50 fast-curing polyester resin for low-gloss powder coatings is prepared from terephthalic acid, neopentyl glycol, 1, 12-dodecanediol, triethanolamine, 1,2, 4-cyclohexanetricarboxylic anhydride, 2-hydroxybenzimidazole and 3, 3-dimethylglutaric anhydride through polymerization.
A50/50 fast curing polyester resin for low-gloss powder coating comprises the following raw materials in parts by mole:
the raw materials can also contain a certain amount of catalyst and antioxidant; preferably, the catalyst is tetrabutyl titanate, and the dosage of the tetrabutyl titanate is 0.05-0.08% of the total molar weight of the main raw materials; the antioxidant is an antioxidant 1076, is named as n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, and the dosage of the antioxidant is 0.03 to 0.05 percent of the total molar weight of the main raw materials.
The preparation method of the 50/50 fast curing polyester resin for the low-gloss powder coating comprises the following steps:
A. adding dimethylbenzene, 1,2, 4-cyclohexane tricarbamic anhydride, 2-hydroxybenzimidazole and a catalyst into a reaction kettle according to the formula ratio, and heating to the boiling point of the dimethylbenzene to carry out full esterification reaction with water;
B. sampling and detecting the hydroxyl value of a reactant of a system, and when the hydroxyl value reaches 3-5mgKOH/g, indicating that 2-hydroxybenzimidazole is almost completely esterified on 1,2, 4-cyclohexane tricarboxylic anhydride to obtain a reaction intermediate A;
the molecular structure of the intermediate may be:
C. adding terephthalic acid, neopentyl glycol and 1, 12-dodecanediol in a formula amount into the mixed material, gradually heating to react to 190-200 ℃, removing a solvent xylene and micromolecular esterified water simultaneously in the heating process, and then carrying out thermal polymerization reaction;
D. sampling and detecting the acid value of the reaction polymer, adding triethanolamine with the formula amount when the acid value is 28-35mgKOH/g, continuing to perform chain extension esterification polymerization reaction, gradually heating to 220-225 ℃, and continuing to perform heat preservation polymerization reaction;
E. adding antioxidant in the formula amount when the acid value of the polymer reaches 20-25mgKOH/g, starting a vacuum system, and heating to 230-235 ℃ to perform vacuum polycondensation;
F. stopping the vacuum system when the acid value of the polymer is reduced to 8-12mgKOH/g, adding 3, 3-dimethyl glutaric anhydride with the formula amount, and continuing to perform carboxyl end capping reaction at 230-235 ℃ under the condition of heat preservation;
G. stopping the reaction when the acid value of the reactant is 40-47mgKOH/g, discharging at high temperature, cooling the polyester resin, and crushing and granulating to obtain the polyester resin.
Preferably, in the step C, the temperature is gradually increased at the temperature increasing speed of 6-8 ℃/h; in the step D, gradually heating at a heating speed of 8-10 ℃/h under the protection of nitrogen; in the step E, the vacuum degree is kept between-0.096 Mpa and-0.098 Mpa; and G, cooling the polyester resin by using a steel belt with condensed water.
For example, the preparation method of the 50/50 fast curing polyester resin for the low-gloss powder coating specifically comprises the following steps:
A. adding the dimethylbenzene, the 1,2, 4-cyclohexane tricarbamic anhydride, the 2-hydroxybenzimidazole and the catalyst into a reaction kettle according to the formula ratio, and heating to the boiling point of the dimethylbenzene to carry out full esterification reaction with water;
B. sampling and detecting the hydroxyl value of a reactant of the system, and when the hydroxyl value reaches 3-5mgKOH/g, indicating that 2-hydroxybenzimidazole is almost completely esterified onto 1,2, 4-cyclohexane tricarboxylic anhydride to obtain a reaction intermediate A;
the molecular structure of the intermediate is as follows:
C. adding terephthalic acid, neopentyl glycol and 1, 12-dodecanediol with a formula amount into the mixed material, gradually heating at a heating speed of 6-8 ℃/h to react to 190-200 ℃, removing a solvent xylene and micromolecule esterified water simultaneously in the heating process, and then carrying out heat preservation polymerization reaction;
D. sampling and detecting the acid value of the reaction polymer, adding triethanolamine with the formula amount when the acid value is 28-35mgKOH/g, continuing to perform chain extension esterification polymerization reaction, then gradually heating to 220-225 ℃ at the heating rate of 8-10 ℃/h under the protection of nitrogen, and continuing to perform heat preservation polymerization reaction;
E. adding antioxidant in the amount of formula when the acid value of the polymer reaches 20-25mgKOH/g, starting a vacuum system, keeping the vacuum degree at-0.096 Mpa to-0.098 Mpa, and heating to 230-235 ℃ to perform vacuum polycondensation;
F. stopping the vacuum system when the acid value of the polymer is reduced to 8-12mgKOH/g, adding 3, 3-dimethyl glutaric anhydride with the formula amount, and continuing to perform the carboxyl end capping reaction at 230-235 ℃;
G. stopping the reaction when the acid value of the reactant is 40-47mgKOH/g, discharging at high temperature, cooling the polyester resin by using a steel belt with condensed water, and then crushing and granulating to obtain the polyester resin.
The obtained product is colorless transparent particles, the acid value is 40-47mgKOH/g, and the softening point is 98-107 ℃.
The invention also relates to the application of the 50/50 fast curing polyester resin for the low-gloss powder coating or the polyester resin obtained by the preparation method in a 50/50 mixed powder coating.
The powder coating comprises polyester resin and E-12 epoxy resin, and can also contain common additives such as titanium dioxide, barium sulfate, a flatting agent, a brightener, benzoin and the like.
The invention has the beneficial effects that:
starting with the design of a chain segment structure and polyester resin with high active end group curing groups, the polyester resin is obtained by polymerizing terephthalic acid, neopentyl glycol, 1, 12-dodecanediol, triethanolamine, cyclohexanetricarboxylic acid, 2-hydroxybenzimidazole, 3-dimethyl glutaric anhydride and the like which are mainly used as raw materials; the finally obtained polyester resin has soft chain segment and low softening point, except that long-chain carboxyl introduced with 3, 3-dimethylglutaric anhydride can be solidified with E-12, the polyester resin is specially introduced with an imidazole group with ultrahigh activity to realize low-temperature rapid solidification, the final product has high solidification speed with E-12 epoxy resin, can realize low-temperature rapid solidification film forming at 160 ℃/8min, has high leveling grade, realizes self-extinction effect due to the difference of the solidification speed because the carboxyl and the imidazoline amino participate in the solidification at the same time, has 20-26 percent of film gloss, and has excellent decorative effect.
Detailed Description
In order to facilitate an understanding of the invention, various exemplary embodiments of the invention will now be described in detail, with the detailed description being not to be considered a specific limitation of the invention, but rather a more detailed description of certain aspects, features and embodiments of the invention.
The raw materials are all commercially available.
Example 1
A50/50 fast curing polyester resin for low-gloss powder coating comprises the following raw materials:
the catalyst is tetrabutyl titanate, and the using amount of the tetrabutyl titanate is 0.05 percent of the total molar amount of the raw materials; the antioxidant is antioxidant 1076, and the dosage of the antioxidant is 0.03 percent of the total molar weight of the raw materials.
The preparation method of the 50/50 fast curing polyester resin for the low-gloss powder coating specifically comprises the following steps:
A. adding dimethylbenzene, 1,2, 4-cyclohexane tricarbamic anhydride, 2-hydroxybenzimidazole and a catalyst into a reaction kettle according to the formula ratio, and heating to the boiling point of the dimethylbenzene to carry out full esterification reaction with water;
B. sampling and detecting the hydroxyl value of a reactant of the system, and when the hydroxyl value reaches 3mgKOH/g, indicating that the 2-hydroxybenzimidazole is almost completely esterified onto 1,2, 4-cyclohexane tricarboxylic anhydride to obtain a reaction intermediate A;
C. adding terephthalic acid, neopentyl glycol and 1, 12-dodecanediol with a formula amount into the mixed material, gradually heating to 190 ℃ at a heating speed of 6 ℃/h, removing a solvent xylene and micromolecular esterified water simultaneously in the heating process, and then carrying out heat preservation polymerization reaction;
D. sampling and detecting the acid value of the reaction polymer, adding triethanolamine with the formula amount when the acid value is 28mgKOH/g, continuing to perform chain extension esterification polymerization reaction, then gradually heating to 222 ℃ at the heating rate of 8 ℃/h under the protection of nitrogen, and continuing to perform heat preservation polymerization reaction;
E. adding antioxidant in the amount of the formula when the acid value of the polymer reaches 22mgKOH/g, starting a vacuum system, keeping the vacuum degree at-0.096 Mpa, and heating to 232 ℃ for vacuum polycondensation;
F. stopping the vacuum system when the acid value of the polymer is reduced to 10mgKOH/g, adding 3, 3-dimethyl glutaric anhydride with the formula amount, and continuing to perform carboxyl end capping reaction at 232 ℃;
G. stopping the reaction when the acid value of the reactant reaches the expected value, discharging at high temperature while the reactant is hot, cooling the polyester resin by using a steel belt with condensed water, and crushing and granulating to obtain the polyester resin.
Finally, the acid value of the prepared polyester resin was 43mgKOH/g, and the softening point was 99 ℃.
Example 2
A50/50 fast curing polyester resin for low-gloss powder coating comprises the following raw materials:
the catalyst is tetrabutyl titanate, and the using amount of the tetrabutyl titanate is 0.07 percent of the total molar amount of the raw materials; the antioxidant is antioxidant 1076, and the dosage of the antioxidant is 0.05 percent of the total molar weight of the raw materials.
The preparation method is the same as example 1.
The obtained product was colorless transparent particles, the acid value was 46mgKOH/g, and the softening point was 107 ℃.
Example 3
A50/50 fast curing polyester resin for low-gloss powder coating comprises the following raw materials:
the catalyst is tetrabutyl titanate, and the using amount of the tetrabutyl titanate is 0.06 percent of the total molar amount of the raw materials; the antioxidant is antioxidant 1076, and the dosage of the antioxidant is 0.05 percent of the total molar weight of the raw materials.
The preparation method is the same as example 1.
The obtained product was colorless transparent particles, the acid value was 43mgKOH/g, and the softening point was 102 ℃.
Example 4
A50/50 fast curing polyester resin for low-gloss powder coating comprises the following raw materials:
the catalyst is tetrabutyl titanate, and the using amount of the tetrabutyl titanate is 0.05 percent of the total molar amount of the raw materials; the antioxidant is antioxidant 1076, and the dosage of the antioxidant is 0.04 percent of the total molar weight of the raw materials.
The preparation method is the same as example 1.
The obtained product was colorless transparent particles, the acid value was 42mgKOH/g, and the softening point was 104 ℃.
Comparative example 1:
a commercially available 50/50 polyester resin with an acid value of 65mgKOH/g and a softening point of 118 ℃ was purchased from New Material Ltd, model SJ3C, anhui Shenjian.
Comparative example 2
The rest was the same as in comparative example 1 except that the solid conditions were changed from 160 deg.C/8 min to 180 deg.C/15 min.
Application example
According to the formulation of a 50/50 hybrid powder coating, the formulation is generally as follows in parts by weight:
preparing a coating layer: mixing the materials according to the formula of 50/50 mixed powder coating, extruding, tabletting and crushing by a double-screw extruder, and then crushing and sieving the tablets to prepare the powder coating. And spraying the powder coating on the galvanized iron substrate subjected to surface treatment by using an electrostatic spray gun, and curing at 160 ℃/8min to obtain the coating.
Comparison of Performance
The detection basis of the coating indexes is as follows: GB/T21776-2008 Standard guidelines for testing powder coatings and coatings therefor. The adhesion test is carried out according to GB/T9286-1998 test for marking the paint film of the colored paint and the varnish; the leveling performance adopts PCI leveling grade, 1-10 grade, and the larger the number is, the better the leveling is.
Polyester resins prepared by the above examples and comparative examples coating formulations according to the present invention were prepared and tested for coating performance results as shown in table 1 below.
TABLE 1 coating film Properties of the powder coatings
As can be seen from the table 1, the polyester resin prepared by the product can realize low-temperature rapid curing with E-12 epoxy resin under the curing condition of 160 ℃/8min, the obtained coating is flat and smooth, the impact resistance is excellent, the leveling grade is basically 6-grade or above, and due to the curing effect of the E-12 epoxy resin while high-activity imidazole groups and high-activity terminal carboxyl groups in chain segments, an obvious self-extinction effect appears due to the difference of curing speed, the gloss is basically 20-26%, and the polyester resin has an excellent low-light decorative effect; the common commercial 50/50 polyester resin product of the comparative example 1 can not be fully cured at 160 ℃/8min, so that the appearance, the impact resistance and the adhesive force of the coating film are poor; comparative example 2 after the curing conditions are improved to 180 ℃/15min, the common commercial 50/50 polyester resin product can realize conventional full curing, the appearance, the impact resistance and the leveling property of the coating film basically meet the application requirements, but the self-extinction effect can not be realized, and the coating film can only be used for preparing high-gloss coating films.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. This need not be, nor should it be exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the spirit or scope of the invention.
Claims (9)
1. A50/50 fast-curing polyester resin for low-gloss powder coatings is prepared from terephthalic acid, neopentyl glycol, 1, 12-dodecanediol, triethanolamine, 1,2, 4-cyclohexanetricarboxylic anhydride, 2-hydroxybenzimidazole and 3, 3-dimethylglutaric anhydride through polymerization.
2. The 50/50 fast-curing polyester resin for low-gloss powder coatings according to claim 1, wherein the raw material composition comprises, in terms of mole fraction:
the feedstock may also contain certain amounts of catalyst and antioxidant.
3. The 50/50 fast curing polyester resin for low gloss powder coatings of claim 2 wherein the catalyst is tetrabutyl titanate used in an amount of 0.05 to 0.08% of the total molar amount of the starting materials.
4. The 50/50 fast-curing polyester resin for low-gloss powder coatings according to claim 2 or 3, wherein the antioxidant is 1076 in an amount of 0.03 to 0.05% based on the total molar amount of the raw materials.
5. The method for preparing a 50/50 fast-curing polyester resin for low gloss powder coatings according to any one of claims 1 to 4, comprising the steps of:
A. adding the dimethylbenzene, the 1,2, 4-cyclohexane tricarbamic anhydride, the 2-hydroxybenzimidazole and the catalyst into a reaction kettle according to the formula ratio, and heating to the boiling point of the dimethylbenzene to carry out full esterification reaction with water;
B. sampling and detecting the hydroxyl value of a system reactant, and obtaining a reaction intermediate A when the hydroxyl value reaches 3-5 mgKOH/g;
C. adding terephthalic acid, neopentyl glycol and 1, 12-dodecanediol in a formula amount into the mixed material, gradually heating to 190-200 ℃, removing the solvent and water simultaneously in the heating process, and then carrying out heat preservation polymerization reaction;
D. sampling and detecting the acid value of the reaction polymer, adding triethanolamine with the formula amount when the acid value is 28-35mgKOH/g, continuing to perform chain extension esterification polymerization reaction, gradually heating to 220-225 ℃, and continuing to perform heat preservation polymerization reaction;
E. adding antioxidant with formula amount when the acid value of the polymer reaches 20-25mgKOH/g, starting a vacuum system, and heating to 230-235 ℃ to perform vacuum polycondensation;
F. stopping the vacuum system when the acid value of the polymer is reduced to 8-12mgKOH/g, adding 3, 3-dimethyl glutaric anhydride with the formula amount, and continuing to perform carboxyl end capping reaction at 230-235 ℃ under the condition of heat preservation;
G. stopping the reaction when the acid value of the reactant is 40-47mgKOH/g, discharging at high temperature, cooling the polyester resin, and crushing and granulating to obtain the polyester resin.
6. The method for preparing a 50/50 fast-curing polyester resin for low-gloss powder coatings according to claim 5, wherein in step C, the temperature is gradually increased at a temperature increase rate of 6-8 ℃/h.
7. The method for preparing a 50/50 fast-curing polyester resin for low-gloss powder coatings according to claim 5, wherein in step D, the temperature is raised gradually at a temperature raising rate of 8-10 ℃/h under the protection of nitrogen.
8. The method for preparing a 50/50 fast curing polyester resin for low gloss powder coating according to claim 5, wherein in the step E, the degree of vacuum is maintained at-0.096 Mpa to-0.098 Mpa; and G, cooling the polyester resin by using a steel belt with condensed water.
9. Use of a 50/50 fast curing polyester resin for low gloss powder coatings according to claims 1-4 or of a polyester resin obtained by the process according to claims 5-8 in 50/50 hybrid powder coatings.
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| JP2001226630A (en) * | 2000-02-17 | 2001-08-21 | Dainippon Ink & Chem Inc | Composition for powdered paint and method of forming coating film |
| CN102604056A (en) * | 2012-03-23 | 2012-07-25 | 浙江天松新材料股份有限公司 | Preparation method of saturated carboxyl polyester resin for powder coating with high surface finishing performance |
| CN109880494A (en) * | 2019-03-06 | 2019-06-14 | 安徽永利新材料科技有限公司 | A kind of indoor high rigidity, high glaze powder 50:50 polyester resin and preparation method thereof |
| CN110591066A (en) * | 2019-10-12 | 2019-12-20 | 黄山市向荣新材料有限公司 | Polyester resin for high-leveling self-curing powder coating and preparation method of two-kettle combined polyester resin |
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- 2022-11-11 CN CN202211414831.4A patent/CN115521447A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001226630A (en) * | 2000-02-17 | 2001-08-21 | Dainippon Ink & Chem Inc | Composition for powdered paint and method of forming coating film |
| CN102604056A (en) * | 2012-03-23 | 2012-07-25 | 浙江天松新材料股份有限公司 | Preparation method of saturated carboxyl polyester resin for powder coating with high surface finishing performance |
| CN109880494A (en) * | 2019-03-06 | 2019-06-14 | 安徽永利新材料科技有限公司 | A kind of indoor high rigidity, high glaze powder 50:50 polyester resin and preparation method thereof |
| CN110591066A (en) * | 2019-10-12 | 2019-12-20 | 黄山市向荣新材料有限公司 | Polyester resin for high-leveling self-curing powder coating and preparation method of two-kettle combined polyester resin |
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