A high temperature resistant polyester resin and preparation method thereof

Abstract

The present invention relates to the field of polymer resin materials, and in particular to a high-temperature resistant polyester resin and a preparation method thereof. The high-temperature resistant polyester resin is prepared from a polyol and a dibasic acid; the polyol is composed of neopentyl glycol and an organosilicon polyol in a mass ratio of 1-4:1; the organosilicon polyol is obtained by reacting octamethylcyclotetrasiloxane and 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and then ring-opening. The high-temperature resistant polyester resin prepared by the present invention has excellent mechanical properties and heat resistance, and has broad application prospects in the fields of engineering plastics, adhesives, coatings, and the like.

Description

Technical Field

[0001] The present invention relates to the field of polymer resin materials, in particular to a high-temperature resistant polyester resin and a preparation method thereof. Background Art

[0002] Polyester resins are polymers formed by the esterification and polycondensation of dibasic acids and polyols. They are widely used in engineering plastics, adhesives, coatings, and other fields. While traditional polyester resins offer excellent weather resistance, mechanical properties, and processing characteristics, they are not heat-resistant and are prone to thermal decomposition, yellowing, and mechanical property degradation in high-temperature environments. This limits their application in aerospace, automotive, electronic devices, high-temperature coatings, and other fields. Summary of the Invention

[0003] Purpose of the invention: In order to solve the above technical problems, the present invention provides a high temperature resistant polyester resin and a preparation method thereof.

[0004] The technical solutions adopted are as follows:

[0005] A high-temperature resistant polyester resin is prepared from polyol and dibasic acid;

[0006] The polyol is composed of neopentyl glycol and silicone polyol in a mass ratio of 1-4:1;

[0007] The organosilicon polyol is obtained by reacting octamethylcyclotetrasiloxane and 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and then ring-opening.

[0008] Furthermore, the preparation method of the organosilicon polyol is as follows:

[0009] 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and octamethylcyclotetrasiloxane are first reacted under the catalytic action of tetramethylammonium hydroxide to obtain an organosilicon epoxy monomer, and the organosilicon epoxy monomer is then ring-opened under the action of a solid acid catalyst to obtain an organosilicon polyol.

[0010] Furthermore, the mass ratio of the 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane to octamethylcyclotetrasiloxane is 1:25-50.

[0011] Furthermore, the solid acid catalyst is metatitanic acid.

[0012] Titanic acid has weak acidity and is insoluble in water. Using it as a catalyst can not only be reused but also effectively avoid the hydrolysis of siloxane.

[0013] Furthermore, the amount of the solid acid catalyst used is 0.1%-1% of the mass of the organosilicon epoxy monomer.

[0014] Furthermore, the preparation method of the organosilicon polyol is as follows:

[0015] Octamethylcyclotetrasiloxane, 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and catalyst tetramethylammonium hydroxide are mixed and heated to 80-120°C and kept for reaction for 5-15 hours, then heated to 140-180°C and kept for reaction for 0.5-1 hour, followed by vacuum distillation to obtain an organosilicon epoxy monomer. The organosilicon epoxy monomer is mixed with water and heated to 70-90°C, and a solid acid catalyst is added and stirred for reaction for 1-5 hours. The organosilicon polyol is obtained by filtering and vacuum distilling the filtrate.

[0016] Furthermore, the dibasic acid consists of terephthalic acid and isophthalic acid.

[0017] Furthermore, the mass ratio of terephthalic acid to isophthalic acid is 4-9:1.

[0018] Furthermore, the mass ratio of the polyol to the dibasic acid is 1:1-3.

[0019] The present invention also provides a method for preparing a high-temperature resistant polyester resin:

[0020] Mix the polyol and dibasic acid, heat to 230-250℃, keep the temperature for reaction for 1-5h, then cool to 180-200℃ and evacuate. When the acid value is ≤3mg KOH / g, stop the vacuum, cool down and discharge the material.

[0021] Beneficial effects of the present invention:

[0022] The present invention provides a high-temperature resistant polyester resin, which uses an organosilicon polyol containing long silicon oxygen chains as a raw material. The Si-O-Si bonds in the organosilicon polyol structure have high bond energy, thereby giving the polyester resin excellent thermal stability. In addition, the multifunctionality of the organosilicon polyol enables the polyester resin to construct a three-dimensional cross-linked network with a branched structure. The increase in cross-linking density not only improves the mechanical properties of the polyester resin, but also improves the heat resistance of the polyester resin. Therefore, the polyester resin has broad application prospects in the fields of engineering plastics, adhesives, coatings, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a preparation route for the organosilicon polyol in Example 1. DETAILED DESCRIPTION

[0024] Unless otherwise specified, the following examples and comparative examples were conducted in parallel, using the same processing steps and parameters.

[0025] Example 1

[0026] A preparation method of high temperature resistant polyester resin:

[0027] 35g of octamethylcyclotetrasiloxane, 1g of 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and 0.15g of catalyst tetramethylammonium hydroxide were mixed and heated to 100℃ for 10h, then heated to 160℃ and continued to react for 1h, and then distilled under reduced pressure to remove small molecular low-boiling substances to obtain an organosilicon epoxy monomer. The organosilicon epoxy monomer and water in a mass ratio of 1:40 were mixed and heated to 80℃, and then 0.5% of the solid acid catalyst metatitanic acid based on the mass of the organosilicon epoxy monomer was added. After stirring and reacting for 5h, the filtrate was filtered and distilled under reduced pressure to obtain an organosilicon polyol. Neopentyl glycol, organosilicon polyol, terephthalic acid and isophthalic acid in a mass ratio of 4:1:9:1 were added to a flask, stirred and heated to 240℃ and reacted for 2.5h, then cooled to 190℃ and vacuumed, and the acid value was ≤3mg. After 100% KOH / g, stop the vacuum, cool down and discharge the material.

[0028] Example 2

[0029] A preparation method of high temperature resistant polyester resin:

[0030] 50g of octamethylcyclotetrasiloxane, 1g of 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and 0.15g of tetramethylammonium hydroxide catalyst were mixed and heated to 80℃ and kept for reaction for 5h, then heated to 140℃ and kept for reaction for 0.5h, and then distilled under reduced pressure to remove small molecular low-boiling substances to obtain an organosilicon epoxy monomer. The organosilicon epoxy monomer and water in a mass ratio of 1:40 were mixed and heated to 70℃, and 0.1% of the solid acid catalyst metatitanic acid based on the mass of the organosilicon epoxy monomer was added. After stirring for reaction for 1h, the filtrate was filtered and distilled under reduced pressure to obtain an organosilicon polyol. Neopentyl glycol, organosilicon polyol, terephthalic acid and isophthalic acid in a mass ratio of 4:1:9:1 were added to a flask, stirred and heated to 230℃ and kept for reaction for 1h, then cooled to 180℃ and vacuumed, and the mixture was stirred until the acid value was ≤3mg. After 100% KOH / g, stop the vacuum, cool down and discharge the material.

[0031] Example 3

[0032] A preparation method of high temperature resistant polyester resin:

[0033] 25g of octamethylcyclotetrasiloxane, 1g of 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and 0.15g of catalyst tetramethylammonium hydroxide were mixed and heated to 120℃ and kept for reaction for 15h, then heated to 180℃ and kept for reaction for 1h, and then distilled under reduced pressure to remove small molecular low-boiling substances to obtain an organosilicon epoxy monomer. The organosilicon epoxy monomer and water in a mass ratio of 1:40 were mixed and heated to 90℃, and then 1% of the solid acid catalyst metatitanic acid based on the mass of the organosilicon epoxy monomer was added. After stirring for reaction for 5h, the filtrate was filtered and distilled under reduced pressure to obtain an organosilicon polyol. Neopentyl glycol, organosilicon polyol, terephthalic acid and isophthalic acid in a mass ratio of 4:1:9:1 were added to a flask, stirred and heated to 250℃ and kept for reaction for 5h, then cooled to 200℃ and vacuumed, and the acid value was ≤3mg. After 100% KOH / g, stop the vacuum, cool down and discharge the material.

[0034] Example 4

[0035] The method is basically the same as Example 1, except that the mass ratio of neopentyl glycol, silicone polyol, terephthalic acid and isophthalic acid is 4:1:4:1.

[0036] Example 5

[0037] The method is basically the same as Example 1, except that the mass ratio of neopentyl glycol, silicone polyol, terephthalic acid and isophthalic acid is 1:1:5:1.

[0038] Example 6

[0039] The powder coating was prepared by batching, premixing, extruding, tableting, crushing, and screening according to the following formula. The prepared powder coating was sprayed on the surface of a degreased and derusted metal plate by electrostatic spraying, and then placed in an oven at 150°C for baking and curing for 20 minutes to obtain a cured coating.

[0040] 52 parts by weight of the high-temperature resistant polyester resin prepared in Example 1

[0041] Curing agent NW-5 13 parts by weight

[0042] 1 part by weight of leveling agent Hyperlev F103

[0043] 0.4 parts by weight of benzoin

[0044] 7.3 parts by weight of carbon black

[0045] 21.3 parts by weight of mica powder

[0046] Example 7

[0047] It is basically the same as Example 6, except that the high-temperature resistant polyester resin prepared in Example 1 is replaced by the high-temperature resistant polyester resin prepared in Example 2.

[0048] Example 8

[0049] It is basically the same as Example 6, except that the high-temperature resistant polyester resin prepared in Example 1 is replaced by the high-temperature resistant polyester resin prepared in Example 3.

[0050] Example 9

[0051] It is basically the same as Example 6, except that the high-temperature resistant polyester resin prepared in Example 1 is replaced by the high-temperature resistant polyester resin prepared in Example 4.

[0052] Example 10

[0053] It is basically the same as Example 6, except that the high-temperature resistant polyester resin prepared in Example 1 is replaced by the high-temperature resistant polyester resin prepared in Example 5.

[0054] Comparative Example 1:

[0055] It is basically the same as Example 6, except that the high-temperature resistant polyester resin prepared in Example 1 is replaced by the commercially available polyester resin Yabang 198.

[0056] Comparative Example 2:

[0057] The method is basically the same as Example 6, except that the high-temperature resistant polyester resin prepared in Example 1 is replaced by the commercially available polyester resin DSM SN889.

[0058] Performance testing:

[0059] ① The thermal properties of the high-temperature resistant polyester resins prepared in Examples 1-5 of the present invention were tested. The glass transition temperature was tested using a NETZSCH 200F3 differential calorimeter with nitrogen purge, a heating rate of 10°C / min, and a temperature range of 20-200°C to determine the glass transition temperature of the high-temperature resistant polyester resin.

[0060] The thermal weight loss temperature was tested using a NETZSCH STA409PC thermogravimetric analyzer with nitrogen purging, a heating rate of 30°C / min, and a temperature range of 30-800°C to measure the thermal weight loss temperature of the high-temperature resistant polyester resin (Note: the temperature at which the polyester resin loses 5% of its mass). The test results are shown in Table 1 below:

[0061] Table 1:

[0062]

[0063] It can be seen from Table 1 above that the high temperature resistant polyester resin prepared in the present invention has excellent high temperature resistance.

[0064] ② Mechanical properties tests were performed on the coatings in Examples 6-10 and Comparative Examples 1-2 respectively.

[0065] The impact resistance of the coating is determined according to GB / T 1732-2020;

[0066] The coating hardness is measured according to GB / T 6739-2006;

[0067] Adhesion is tested according to standard GB / T 9286-2021;

[0068] The test results are shown in Table 2 below:

[0069] Table 2:

[0070]

[0071] As can be seen from Table 2 above, the powder coating prepared using the high-temperature resistant polyester resin of the present invention has excellent mechanical properties.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high temperature resistant polyester resin, characterized in that: Prepared from polyols and dibasic acids; The polyol is composed of neopentyl glycol and silicone polyol in a mass ratio of 1-4:1; The organosilicon polyol is obtained by reacting octamethylcyclotetrasiloxane and 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and then ring-opening. The preparation method of the organosilicon polyol is as follows: 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and octamethylcyclotetrasiloxane are first reacted under the catalytic action of tetramethylammonium hydroxide to obtain an organosilicon epoxy monomer, which is then ring-opened under the action of a solid acid catalyst to obtain an organosilicon polyol. The mass ratio of the 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane to octamethylcyclotetrasiloxane is 1:25-50.

2. The high temperature resistant polyester resin according to claim 1, characterized in that The solid acid catalyst is metatitanic acid.

3. The high temperature resistant polyester resin according to claim 2, characterized in that The amount of the solid acid catalyst used is 0.1%-1% of the mass of the organosilicon epoxy monomer.

4. The high temperature resistant polyester resin according to claim 1, characterized in that The preparation method of the organosilicon polyol is as follows: Octamethylcyclotetrasiloxane, 1,3-bis(3-glycidyloxypropyl)-1,1,3,3-tetramethyldisiloxane and catalyst tetramethylammonium hydroxide are mixed and heated to 80-120°C and kept for reaction for 5-15 hours, then heated to 140-180°C and kept for reaction for 0.5-1 hour, followed by reduced pressure distillation to obtain an organosilicon epoxy monomer, the organosilicon epoxy monomer is mixed with water and heated to 70-90°C, a solid acid catalyst is added, stirred and reacted for 1-5 hours, filtered and the filtrate is distilled under reduced pressure to obtain an organosilicon polyol.

5. The high temperature resistant polyester resin according to claim 1, characterized in that The dibasic acid consists of terephthalic acid and isophthalic acid.

6. The high temperature resistant polyester resin according to claim 5, characterized in that The mass ratio of terephthalic acid to isophthalic acid is 4-9:

1.

7. The high temperature resistant polyester resin according to claim 1, characterized in that The mass ratio of the polyol to the dibasic acid is 1:1-3.

8. A method for preparing a high temperature resistant polyester resin according to any one of claims 1 to 7, characterized in that: Mix the polyol and dibasic acid, heat to 230-250℃, keep the temperature for reaction for 1-5h, then cool to 180-200℃ and evacuate. When the acid value is ≤3mg KOH / g, stop the vacuum, cool down and discharge the material.

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