Polyester resin for powdery coating with self catalytic activity, preparation method thereof and powdery coating containing polyester resin

Abstract

The invention relates to polyester resin for powdery coating with self catalytic activity, a preparation method thereof and the powdery coating containing the polyester resin. The polyester resin is prepared from the main raw materials including dimethyl terephthalate, trimellitic acid ester with quarternary ammonium salt group, dicarboxylic acid, dihydric alcohol, N,N-dihydroxypropyl diethyl ammonia chloride, and an acidifying agent via copolymerizing reaction. The polyester resin has the advantages that the quarternary ammonium salt active catalyzing group is carried in the finally obtained polyester resin chain segment, so that under the condition of no additional adding of curing accelerant, the curing activity is better, the influence to the curing activity after storage for a long time is avoided, the acid value is 65 to 75mgKOH / g, and the curing film layer is excellent.

Description

technical field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a polyester resin for powder coatings with self-catalysis activity, a preparation method thereof and a powder coating containing the same. Background technique

[0002] Powder coating is a new type of solvent-free 100% solid powder coating. Powder coating is a completely different form from general coatings, and it exists in the state of fine powder. Because no solvent is used, it is called powder coating. Powder coating has the characteristics of solvent-free, pollution-free, recyclable, environmental protection, energy and resource saving, labor intensity reduction and high mechanical strength of the coating film.

[0003] There are two types of powder coatings: thermoplastic powder coatings and thermosetting powder coatings. Thermoplastic powder coatings are composed of thermoplastic resins, pigments, fillers, plasticizers and stabilizers. Thermoplastic powder...

Examples

Embodiment 1

[0060] A polyester resin for powder coatings with self-catalytic activity, its raw material composition and molar ratio are: 25 mol of dimethyl terephthalate, 15 mol of trimellitate with quaternary ammonium salt groups, sebacic acid 15mol, 25mol of diethylene glycol, 12mol of 2,2,4-trimethyl-1,3-pentanediol, 10mol of N,N-dihydroxypropyl diethylammonium chloride, 5mol of trihydroxymethylaminomethane , 10 mol of succinic anhydride, 31140.35 mol of antioxidant.

[0061] The preparation method of the powder coating polyester resin of self-catalysis activity comprises the following steps:

[0062] A. Add the formulated amount of dimethyl terephthalate, trimellitate with quaternary ammonium salt group, and sebacic acid into the mixer, and heat and melt below 145°C;

[0063] B. Add the formulated amount of diethylene glycol, 2,2,4-trimethyl-1,3-pentanediol and trihydroxymethylaminomethane to the above mixed material, and add 0.1-0.2% of the total mass of raw materials at the same ti...

Embodiment 2

[0068] Same as Example 1, except that the composition of raw materials is as follows: 30 mol of dimethyl terephthalate, 15 mol of trimellitate with quaternary ammonium salt group, 15 mol of sebacic acid, 10 mol of diethylene glycol, 2,2,4 - Trimethyl-1,3-pentanediol 10mol, N,N-dihydroxypropyldiethylammonium chloride 5mol, trishydroxymethylaminomethane 5mol, succinic anhydride 10mol, antioxidant 31140.3mol.

[0069] The prepared low-temperature-curable polyester resin for powder coatings has an acid value of 68 mgKOH / g, a softening point of 104° C., and a gelation time of 144 s.

Embodiment 3

[0071] Same as Example 1, except that the composition of raw materials is as follows: 22 mol of dimethyl terephthalate, 5 mol of trimellitate with quaternary ammonium salt group, 8 mol of sebacic acid, 25 mol of diethylene glycol, 2,2,4 - 15 mol of trimethyl-1,3-pentanediol, 15 mol of N,N-dihydroxypropyldiethylammonium chloride, 3 mol of trishydroxymethylaminomethane, 7 mol of succinic anhydride, 31140.3 mol of antioxidant.

[0072] The prepared low-temperature-curable polyester resin for powder coatings has an acid value of 72 mgKOH / g, a softening point of 118° C., and a gelation time of 140 s.

technical field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a polyester resin for powder coatings with self-catalysis activity, a preparation method thereof and a powder coating containing the same. Background technique

[0002] Powder coating is a new type of solvent-free 100% solid powder coating. Powder coating is a completely different form from general coatings, and it exists in the state of fine powder. Because no solvent is used, it is called powder coating. Powder coating has the characteristics of solvent-free, pollution-free, recyclable, environmental protection, energy and resource saving, labor intensity reduction and high mechanical strength of the coating film.

[0003] There are two types of powder coatings: thermoplastic powder coatings and thermosetting powder coatings. Thermoplastic powder coatings are composed of thermoplastic resins, pigments, fillers, plasticizers and stabilizers. Thermoplastic powder...

Examples

Embodiment 1

[0060] A polyester resin for powder coatings with self-catalytic activity, its raw material composition and molar ratio are: 25 mol of dimethyl terephthalate, 15 mol of trimellitate with quaternary ammonium salt groups, sebacic acid 15mol, 25mol of diethylene glycol, 12mol of 2,2,4-trimethyl-1,3-pentanediol, 10mol of N,N-dihydroxypropyl diethylammonium chloride, 5mol of trihydroxymethylaminomethane , 10 mol of succinic anhydride, 31140.35 mol of antioxidant.

[0061] The preparation method of the powder coating polyester resin of self-catalysis activity comprises the following steps:

[0062] A. Add the formulated amount of dimethyl terephthalate, trimellitate with quaternary ammonium salt group, and sebacic acid into the mixer, and heat and melt below 145°C;

[0063] B. Add the formulated amount of diethylene glycol, 2,2,4-trimethyl-1,3-pentanediol and trihydroxymethylaminomethane to the above mixed material, and add 0.1-0.2% of the total mass of raw materials at the same ti...

Embodiment 2

[0068] Same as Example 1, except that the composition of raw materials is as follows: 30 mol of dimethyl terephthalate, 15 mol of trimellitate with quaternary ammonium salt group, 15 mol of sebacic acid, 10 mol of diethylene glycol, 2,2,4 - Trimethyl-1,3-pentanediol 10mol, N,N-dihydroxypropyldiethylammonium chloride 5mol, trishydroxymethylaminomethane 5mol, succinic anhydride 10mol, antioxidant 31140.3mol.

[0069] The prepared low-temperature-curable polyester resin for powder coatings has an acid value of 68 mgKOH / g, a softening point of 104° C., and a gelation time of 144 s.

Embodiment 3

[0071] Same as Example 1, except that the composition of raw materials is as follows: 22 mol of dimethyl terephthalate, 5 mol of trimellitate with quaternary ammonium salt group, 8 mol of sebacic acid, 25 mol of diethylene glycol, 2,2,4 - 15 mol of trimethyl-1,3-pentanediol, 15 mol of N,N-dihydroxypropyldiethylammonium chloride, 3 mol of trishydroxymethylaminomethane, 7 mol of succinic anhydride, 31140.3 mol of antioxidant.

[0072] The prepared low-temperature-curable polyester resin for powder coatings has an acid value of 72 mgKOH / g, a softening point of 118° C., and a gelation time of 140 s.

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