HAA (hydroxyalkylamide) cured carboxyl-terminated saturated polyester resin for thermal transfer powder coating and synthesis method of carboxyl-terminated saturated polyester resin

Abstract

The invention provides HAA (hydroxyalkylamide) cured carboxyl-terminated saturated polyester resin for thermal transfer powder coating and a synthesis method of the carboxyl-terminated saturated polyester resin. The resin is mainly prepared from raw materials in percentage by weight as follows: 30wt%-45wt% of polyol, 43wt%-55wt% of aromatic polyacid, 0.01wt%-3wt% of a branching agent, 8wt%-18wt% of an acidolysis agent, 0.03wt%-0.15wt% of an esterifying catalyst and 0.01wt%-2wt% of an antioxidant through melt polycondensation. The resin has the advantages that the resin has proper glass transition temperature and storage stability, the resin synthesis process is simple, the resin coat is low and the like, the resin components meet the requirement about polyester resin for powder coatings inGB/T 5237.4-2008 aluminum alloy building profile section 4: powder spray profile, a coating formed after the powder coating prepared from the resin and HAA is cured has good leveling and mechanical performance, has weather resistance meeting the class II standard in GB/T 5237.4-2008 aluminum alloy building profile section 4: powder spray profile, thermal transfer patterns are clear and have no offset print.

Description

Technical field [0001] The invention relates to the field of powder coatings, in particular to a carboxyl-terminated saturated polyester resin for hydroxyalkylamide curing thermal transfer powder coatings and a synthesis method thereof. Background technique [0002] At present, one of the large number of application fields of powder coatings is aluminum profiles. The latest national standard "GB / T 5237.4-2008 Aluminum Alloy Building Profiles Part 4: Powder Coating Profiles" puts forward a lot of requirements for polyester resins for powder coatings. The details are as follows: 1. Synthetic polyester polyols are usually neopentyl glycol, and other polyols that do not contain ß hydrogen can also be used. Pay attention to the purity of the polyols. Neopentyl glycol should be produced by hydrogenation. Ethylene glycol, diethylene glycol, and propylene glycol are not allowed; to improve resin intermediate phthalic acid (or other dibasic acids with better weather resistance than isopht...

AI Technical Summary

Problems solved by technology

At present, there are a large number of HAA-cured polyester resins on the market for conventional applications, but there are no commercial products in the field of thermal transfer powder coatings.

[0005] CN107619472A discloses a method for preparing a resin for thermal transfer powder coatings. The use of PET components in the raw materials results in a large amount of beta hydrogen in the system, which leads to insufficient weather resistance and cannot meet the requirements of "GB / T 5237.4-2008 Aluminum Alloy Building Profiles Part 4: Requirements for Duster Profiles

CN105367765B discloses a method for preparing a resin for super-tough thermal transfer powder coatings. It adds a large amount of 2-methyl-1,3 propanediol to the formula to increase the toughness of the system, so the overall weather resistance is low

According to the actual feedback, the final sample coating has poor leveling and low weather resistance, which cannot meet the requirements of "GB / T 5237.4-2008 Aluminum alloy building profiles-Part 4: Dust-sprayed profiles"

CN102977346B discloses a polyester resin for curing weather-resistant powder coatings by TGIC. However, the acid value of the final polyester resin is 32-36, and the low acid value makes the crosslinking degree of the final coating low, which is not conducive to thermal transfer printing.

At the same time, the content of isophthalic acid in the resin accounts for about 11% of the resin, and the weather resistance is low, which cannot meet the requirements in "GB / T 5237.4-2008 Aluminum Alloy Building Profiles Part 4: Powder Spraying Profiles"

CN1023304790A discloses a polyester resin for thermal transfer powder coating of outdoor aluminum profiles. The description in this patent indicates that a large amount of ethyl butyl propylene glycol is used in the formula, and there is no isophthalic acid in the formula, which also cannot meet the latest standards. Requirements of "GB / T 5237.4-2008 Aluminum Alloy Building Profiles Part 4: Powder Coated Profiles"

CN107778466A discloses a kind of polyester resin for HAA solidified thermal transfer powder coating, there is a large amount of ethylene glycol and diethylene glycol in this polyester resin, also can't meet "GB / T5237.4-2008 aluminum alloy building profiles No. Part 4: Requirements for polyester resins in Powder Spraying Profiles. At the same time, the presence of hydroxyl-terminated silicone oil in the formula will pollute the reactor, making the possibility of product switching in the production line zero, so it cannot be applied in actual production.

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