A kind of thermosetting saturated carboxyl-terminated polyester resin and preparation method thereof

A carboxyl-terminated polyester and thermosetting technology, which is applied in the field of thermosetting saturated carboxyl-terminated polyester resin and its preparation, can solve the problems of unfavorable curing process of powder coating, low glass transition temperature, orange peel phenomenon in coating film and the like, Achieve the effect of solving stability and curing reaction activity, good crystallization performance, and improving storage stability

Active Publication Date: 2016-08-24
佛山市南海嘉多彩粉末涂料有限公司
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  • Application Information

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Problems solved by technology

At present, the carboxyl-terminated polyester resin commonly used in thermosetting powder compositions is synthesized by direct esterification with neopentyl glycol (NPG) and terephthalic acid (TPA) as the main monomers, and has an amorphous structure. The linear polycondensation product, its molecular main chain is composed of saturated single bonds, and the flexibility of the molecular chain is good, resulting in a low glass transition temperature (Tg), which easily leads to the agglomeration and stability decrease of the powder coating prepared by polyester resin. Therefore, the Tg of the resin must be increased
However, the practice of increasing the Tg of amorphous polyester resin by increasing the high molecular weight of the resin, moderate crosslinking and other means often increases the melt viscosity of the coating system while increasing the Tg of the resin, reduces the curing reactivity of the resin, and improves the coating performance. High curing temperature, even lead to orange peel phenomenon in the coating film, which is very unfavorable to the curing and film-forming process of powder coatings

Method used

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  • A kind of thermosetting saturated carboxyl-terminated polyester resin and preparation method thereof
  • A kind of thermosetting saturated carboxyl-terminated polyester resin and preparation method thereof
  • A kind of thermosetting saturated carboxyl-terminated polyester resin and preparation method thereof

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preparation example Construction

[0030] A method for preparing a thermosetting saturated carboxyl-terminated polyester resin, which uses diol monomers and dibasic acid monomers as raw materials and obtains them through direct esterification and a two-step synthesis process of esterification and carboxylation. The reaction principle is as follows :

[0031] The first step: polycondensation reaction, esterification and condensation into a polyester resin with a low degree of polymerization and a hydroxyl-terminated polyester resin,

[0032]

[0033] The second step: carboxylation, mainly by adding a dibasic acid to react with the above-condensed low-polymerization polyester resin to produce a carboxyl-terminated polyester resin,

[0034]

[0035] Wherein, R1: dibasic alcohol monomer structure, R2: dibasic acid monomer structure.

Embodiment 1

[0037] (1) Add 60 g of neopentyl glycol monomer and 0.3 g of catalyst n-butyl stannoic acid into the reaction vessel, after shaking and mixing, start to heat up and heat to about 130 ° C, keep warm, and observe that the neopentyl glycol monomer in the flask is completely After melting, add 80g of terephthalic acid monomer and stir evenly.

[0038] (2) Fill the reaction system with N 2 Gas, pump and charge three times, keep the system at N 2 In an air atmosphere, heat up to 230°C. Under this condition, diols and dibasic acid monomers undergo esterification and polycondensation reactions, and keep warm until the acid value of the reaction system is lower than 5mg KOH / g.

[0039] (3) Stop heating, control the temperature of the reaction system to drop to 170°C, then add 15g of adipic acid monomer to the reaction system according to the formula, and pay attention to maintaining the N of the system. 2 Then slowly heat up to 235°C, continue the polycondensation reaction, keep warm...

Embodiment 2

[0045] The present embodiment is basically the same as Example 1, and its difference is that in (1), the quality of the neopentyl glycol monomer is 50g, the catalyst n-butylstannoic acid is 0.4g, and the quality of the terephthalic acid monomer is 70g ; In (3), the additional adipic acid monomer is 15g; in (4), the added triphenyl phosphite is 0.4g; in (6), the added trimellitic anhydride 15g. According to the XRD powder diffraction test results, the crystallinity of the sample is 17.75%.

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Abstract

The invention discloses a thermosetting saturated carboxyl-terminated polyester resin and a preparation method thereof. The raw materials include dibasic or polybasic acid monomers, dibasic or polyvalent alcohol monomers, catalysts, heat stabilizers and acidifiers, and the crystallinity can be as high as 47.85%, good crystallinity, it uses dibasic or polyalcohol, dibasic or polybasic acid as raw material, (1) rigid groups such as phenyl and cyclic compounds are introduced into the main chain, which hinders the rotation of single bonds and reduces the The flexibility of the main chain of the polyester resin molecule increases the Tg of the resin and improves the storage stability of the powder coating produced by it; (2) The monomer with a symmetrical structure improves the regularity of the molecular chain, makes the resin partially crystallize, and forms a crystalline structure It is beneficial to reduce the melt viscosity of the powder coating system configured with the resin and improve the reactivity of the resin and the curing agent. The polyester resin has undergone a fundamental change in the molecular structure, and the synthesized thermosetting saturated carboxyl-terminated polyester resin has low viscosity, high Tg properties.

Description

technical field [0001] The invention relates to the field of polymer polyester resin synthesis, in particular to a thermosetting saturated carboxyl-terminated polyester resin with a certain degree of crystallinity and a preparation method thereof. Background technique [0002] Thermosetting polyester powder coating has excellent weather resistance, corrosion resistance, electrical properties and mechanical properties, and has no VOC volatilization, simple process, easy automation and recyclable powder. It is a category with a large amount Environmentally friendly powder coating. At present, the powder coatings for industrialized production and large-scale application are all thermosetting resin systems. More than half of the production of thermosetting powder coatings in the world uses polyester resin as an important part of the base material. Due to its excellent comprehensive performance and relatively low cost, thermosetting polyester powder coatings are widely used in t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G63/20C08G63/78
Inventor 陈东初叶秀芳
Owner 佛山市南海嘉多彩粉末涂料有限公司
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