阅读说明：本技术 一种超低温固化混合型聚酯树脂及其合成方法 (Ultralow-temperature curing mixed polyester resin and synthetic method thereof ) 是由 不公告发明人 于 2020-10-11 设计创作，主要内容包括：本发明公开了一种超低温固化的混合型聚酯树脂及其合成方法,树脂按重量份组成为：对苯二甲酸100重量份,新戊二醇50~80重量份,乙二醇10~40重量份,三羟甲基丙烷5~10重量份,三羟甲基乙烷5~10重量份,富马酸10~30重量份,己二酸10~50重量份。引入一定量的支化链单体三羟甲基丙烷、三羟甲基乙烷,增加树脂的活性,同时封端剂采用己二酸和少量富马酸,改善板面流平和冲击性能。调节咪唑类固化促进剂的种类和用量,提高粉末涂料固化速度,实现超低温固化,最低可实现120℃/20min固化。(The invention discloses an ultralow temperature solidified mixed polyester resin and a synthesis method thereof, wherein the resin comprises the following components in parts by weight: 100 parts by weight of terephthalic acid, 50-80 parts by weight of neopentyl glycol, 10-40 parts by weight of ethylene glycol, 5-10 parts by weight of trimethylolpropane, 5-10 parts by weight of trimethylolethane, 10-30 parts by weight of fumaric acid and 10-50 parts by weight of adipic acid. A certain amount of branched chain monomers such as trimethylolpropane and trimethylolethane are introduced to increase the activity of the resin, and meanwhile, adipic acid and a small amount of fumaric acid are adopted as a capping agent to improve the leveling and impact properties of the plate surface. The type and the dosage of the imidazole curing accelerator are adjusted, the curing speed of the powder coating is improved, ultralow temperature curing is realized, and the curing at 120 ℃/20min can be realized at least.)

1. An ultra-low temperature curing mixed polyester resin is characterized in that: the polyester resin comprises 100 parts by weight of terephthalic acid, 50-80 parts by weight of neopentyl glycol, 10-40 parts by weight of ethylene glycol, 5-10 parts by weight of trimethylolpropane, 5-10 parts by weight of trimethylolethane, 10-30 parts by weight of fumaric acid and 10-50 parts by weight of adipic acid.

2. The ultra-low temperature curing hybrid polyester resin as claimed in claim 1, wherein: the curing accelerator comprises: and 5-30 parts by weight of imidazole curing accelerator.

3. The ultra-low temperature curing hybrid polyester resin as claimed in claim 1, wherein: the imidazole curing accelerator is one or a combination of more of imidazole, 2-methylimidazole and 2-phenylimidazoline.

4. The ultra-low temperature curing hybrid polyester resin and the synthesis method thereof as claimed in claim 1, wherein: the synthesis process of the ultralow temperature curing mixed type polyester resin is as follows: heating the kettle to 90-100 ℃ in a synthesis kettle, sequentially adding polyol, polybasic acid and a catalyst, sealing the kettle after feeding, heating, introducing nitrogen for production protection, maintaining the reaction for 2 hours when the temperature rises to 245 ℃, sampling until the kettle liquid is transparent, clear and sampled, and detecting the acid value of 18-22 mgKOH/g; reducing the temperature of the kettle to about 230 ℃, adding a blocking agent, then heating to 235 ℃, maintaining the reaction for 1-3 hours until the kettle liquid is transparent, clear and sampled, and detecting the reaction product until the acid value is 58-62 mgKOH/g; and (3) carrying out vacuum operation, keeping the kettle temperature at 225-235 ℃, keeping the vacuum degree below-0.10 MPa, reacting for 1-4 hours, sampling, detecting the acid value at 45-55 mgKOH/g and the viscosity at 0.3-0.4 Pa.s, then adding a curing accelerator, keeping for 30 minutes, completing the reaction, and discharging.

The technical field is as follows:

the invention relates to a synthetic method of thermosetting mixed polyester resin, in particular to a preparation method of 60/40 mixed polyester resin cured at ultralow temperature.

Background

The powder coating has the advantages of no pollution, energy conservation, recyclability, excellent comprehensive performance and the like, has great advantages in the coating industry, and is rapidly developed in recent years. The mixed polyester resin and epoxy resin are cured, are mainly applied indoors, and have good decorative performance, acid resistance, alkali resistance and corrosion resistance. The hybrid polyester resins are mainly of three types 50/50, 60/40 and 70/30. The curing condition is generally 180-200 ℃/10-15 minutes.

With the further upgrading of energy-saving and environment-friendly requirements, the development of polyester resin of a low-temperature curing system becomes a development trend of the powder coating industry. Meanwhile, the ultralow temperature curing resin can expand the application field of powder coating, such as the furniture industry.

Disclosure of Invention

The invention aims to provide an ultralow-temperature curing mixed polyester resin and a synthesis method thereof.

The purpose of the invention is realized by the following technical scheme: the ultralow-temperature curing mixed type polyester resin comprises, by weight, 100 parts of terephthalic acid, 50-80 parts of neopentyl glycol, 10-40 parts of ethylene glycol, 5-10 parts of trimethylolpropane, 5-10 parts of trimethylolethane, 10-30 parts of fumaric acid and 10-50 parts of adipic acid.

The ultralow-temperature curing mixed polyester resin is characterized in that: the curing accelerator comprises: and 5-30 parts by weight of imidazole curing accelerator.

The ultralow-temperature curing mixed polyester resin is characterized in that: the imidazole curing accelerator is one or a combination of more of imidazole, 2-methylimidazole and 2-phenylimidazoline.

The synthesis process of the ultralow temperature curing mixed type polyester resin is as follows: heating the kettle to 90-100 ℃ in a synthesis kettle, sequentially adding polyol, polybasic acid and a catalyst, sealing the kettle after feeding, heating, introducing nitrogen for production protection, maintaining the reaction for 2 hours when the temperature rises to 245 ℃, sampling until the kettle liquid is transparent, clear and sampled, and detecting the acid value of 18-22 mgKOH/g; reducing the temperature of the kettle to about 230 ℃, adding a blocking agent, then heating to 235 ℃, maintaining the reaction for 1-3 hours until the kettle liquid is transparent, clear and sampled, and detecting the reaction product until the acid value is 58-62 mgKOH/g; and (3) carrying out vacuum operation, keeping the kettle temperature at 225-235 ℃, keeping the vacuum degree below-0.10 MPa, reacting for 1-4 hours, sampling, detecting the acid value at 45-55 mgKOH/g and the viscosity at 0.3-0.4 Pa.s, then adding a curing accelerator, keeping for 30 minutes, completing the reaction, and discharging.

Compared with the prior art, in order to realize ultralow temperature curing, a certain amount of branched chain monomers trimethylolpropane and trimethylolethane are introduced to increase the activity of the resin, a flexible monomer adipic acid is selected as a capping agent, and a small amount of fumaric acid is introduced to improve the impact resistance of the resin. The type and the dosage of the imidazole curing accelerator are adjusted, the curing speed of the powder coating is improved, ultralow temperature curing is realized, and the curing at 120 ℃/20min can be realized at least.

Detailed Description

The invention relates to an ultra-low temperature curing mixed polyester resin and a synthetic method thereof,

example 1:

the main components are as follows:

100 parts by weight of terephthalic acid;

neopentyl glycol 70 parts by weight;

ethylene glycol 30 parts by weight

40 parts by weight of trimellitic anhydride;

10 parts by weight of adipic acid;

4 parts of antioxidant;

6 parts of curing accelerator.

The synthesis process of the ultra-low temperature curing mixed type polyester resin in the embodiment is as follows: heating the kettle to 90-100 ℃ in a synthesis kettle, sequentially adding polyol, polybasic acid and a catalyst, sealing the kettle after feeding, heating, introducing nitrogen for protection, maintaining the reaction for 2 hours when the temperature rises to 245 ℃, and sampling until the kettle liquid is transparent, clear and sampled, wherein the acid value is 18-22 mgKOH/g; reducing the temperature of the kettle to below 210 ℃, adding end capping agents trimellitic anhydride and adipic acid, then heating to 220 ℃, maintaining the reaction for 2 hours, and detecting when the kettle liquid is transparent, clear and sampled, wherein the acid value is 58-62 mgKOH/g; and (3) carrying out vacuum operation, keeping the kettle temperature at 220 ℃, keeping the vacuum degree below-0.10 MPa, reacting for 2 hours, and sampling to detect that the acid value is 45-55 mgKOH/g and the viscosity is 0.3-0.4 Pa.s. Then adding a curing accelerator, maintaining for 30 minutes, finishing the reaction, and discharging.

The invention relates to an ultra-low temperature curing mixed polyester resin and a synthetic method thereof,

example 2: the main components are as follows:

100 parts by weight of terephthalic acid;

60 parts by weight of neopentyl glycol;

ethylene glycol 30 parts by weight

5 parts by weight of trimethylolpropane;

5 parts by weight of trimethylolethane;

50 parts by weight of adipic acid;

4 parts of antioxidant;

10 parts by weight of curing accelerator.

The preparation process of the ultra-low temperature curing mixed type polyester resin of the embodiment is as follows: heating the kettle to 90-100 ℃ in a synthesis kettle, sequentially adding polyol, polybasic acid and a catalyst, sealing the kettle after feeding, heating, introducing nitrogen for protection, maintaining the reaction for 2 hours when the temperature rises to 245 ℃, and sampling until the kettle liquid is transparent, clear and sampled, wherein the acid value is 18-22 mgKOH/g; reducing the temperature of the kettle to about 230 ℃, adding a blocking agent, then heating to 235 ℃, maintaining the reaction for 2 hours until the kettle liquid is transparent, clear, sampled and detected, and the acid value is 58-62 mgKOH/g; and (3) carrying out vacuum operation, keeping the kettle temperature at 230 ℃, keeping the vacuum degree below-0.10 MPa, reacting for 3 hours, sampling and detecting that the acid value is 45-55 mgKOH/g and the viscosity is 0.3-0.4 Pa.s, then adding a curing accelerator, keeping for 30 minutes, completing the reaction, and discharging.

The invention relates to an ultra-low temperature curing mixed polyester resin and a synthetic method thereof,

example 3: the main components are as follows:

100 parts by weight of terephthalic acid;

60 parts by weight of neopentyl glycol;

ethylene glycol 25 parts by weight

8 parts of trimethylolpropane;

5 parts by weight of trimethylolethane;

35 parts by weight of adipic acid;

fumaric acid 15 parts by weight

4 parts of antioxidant;

20 parts of curing accelerator.

A process for preparing an ultra-low temperature curing hybrid type polyester resin of this example is the same as that of example 2.

The invention relates to an ultra-low temperature curing mixed polyester resin and a synthetic method thereof,

example 4: the main components are as follows:

100 parts by weight of terephthalic acid;

60 parts by weight of neopentyl glycol;

ethylene glycol 25 parts by weight

10 parts by weight of trimethylolpropane;

10 parts by weight of trimethylolethane;

30 parts by weight of adipic acid;

fumaric acid 20 parts by weight

4 parts of antioxidant;

20 parts of curing accelerator.

A process for preparing an ultra-low temperature curing hybrid type polyester resin of this example is the same as that of example 2.

The invention relates to an ultra-low temperature curing mixed polyester resin and a synthetic method thereof,

example 5: the main components are as follows:

100 parts by weight of terephthalic acid;

60 parts by weight of neopentyl glycol;

ethylene glycol 25 parts by weight

10 parts by weight of trimethylolpropane;

10 parts by weight of trimethylolethane;

30 parts by weight of adipic acid;

fumaric acid 20 parts by weight

4 parts of antioxidant;

25 parts by weight of a curing accelerator.

The procedure for preparing an ultra-low temperature curing hybrid type polyester resin of this example was the same as example 2 except that the vacuum temperature was 225 c and the vacuum time was 3.5 hours.

The properties of the ultra-low temperature curing hybrid polyester resins prepared in examples 1 to 5 are shown in Table 1:

TABLE 1

As can be seen from Table 1, trimethylolpropane and trimellitic anhydride can raise the softening point and glass transition temperature of the resin, while adipic acid can lower the glass transition temperature of the resin, and by adjusting the proportions of the various raw materials, a mixed resin with good comprehensive indexes can be obtained.

The secondary properties of the powder coatings formulated from the resins prepared in examples 1-5 are shown in Table 2 below (curing conditions 120 deg.C/20 min)

TABLE 2

As can be seen from Table 2, trimethylolpropane and trimethylolethane significantly improve the resin activity and shorten the gel time, and adipic acid and fumaric acid also significantly improve the impact resistance of the board surface. By adjusting the weight parts of various raw materials and the dosage of the curing accelerator, the ultralow temperature curing is realized on the premise of ensuring the leveling property and the impact property of the board surface.