Hydroxyl-terminated polyester resin, preparation method therefor and use thereof
A hydroxyl-terminated polyester resin, a preparation method therefor and use thereof. The hydroxyl-terminated polyester resin is composed of the following raw materials in parts by mass: 25-50 parts of a diol, 40-70 parts of a dibasic acid, 0.1-2 parts of glycidyl tertcarbonate, 0.5-4 parts of a hydroxylation reagent, 0.08-0.3 parts of a catalyst and 0.2-0.5 parts of an antioxidant. The acid value of the polyester resin is 1-8 mgKOH/g, the hydroxyl value is 20-30 mgKOH/g, the melt viscosity at 200° C. is 9000-13000 mPa·s, the reactivity at 180° C. is 410-520 s, the glass transition temperature is 53-59° C., and the softening point is 101-106° C.
1 . A hydroxyl-terminated polyester resin consisting of the following components in parts by mass: 25-50 parts of diol, 40-70 parts of dibasic acid, 0.1-2 parts of glycidyl tertcarbonate, 0.5-4 parts of a hydroxylation reagent, 0.08-0.3 parts of a catalyst, and 0.2-0.5 parts of an antioxidant, wherein:
the diol consists of the following components in percentage by weight: 60%-97% of neopentyl glycol, 1%-25% of 1,4-cyclohexanedimethanol, 0-25% of ethylene glycol, 0-20% of 2-ethyl-2-butyl-1,3-propanediol, 0-10% of 1,2-propanediol, 0-10% of 2-methyl-1,3-propanediol and 0-10% of 1,6-hexanediol;
the dibasic acid is at least one selected from the group consisting of an aromatic dibasic acid and an aliphatic dibasic acid; the aromatic dibasic acid comprises terephthalic acid and isophthalic acid, wherein the mass of isophthalic acid accounts for 0-15% of the mass of aromatic dibasic acid; the aliphatic dibasic acid is at least one selected from the group consisting of 1,4-succinic acid, 1,6-hexanedioic acid, 1,10-decanedioic acid, dodecanedioic acid and 1,4-cyclohexanedicarboxylic acid;
the hydroxylation reagent is at least one selected from the group consisting of 1,2,3,4,5-pentitol, 1,2,3,4,5,6-hexanehexol and 2,2-dihydroxymethyl-butanol; and
the hydroxyl value of the hydroxyl-terminated polyester resin is 20-30 mgKOH/g, and the acid value of the hydroxyl-terminated polyester resin is 1-8 mg KOH/g.
2 . The hydroxyl-terminated polyester resin according to claim 1 , wherein the melt viscosity of the hydroxyl-terminated polyester resin at 200° C. is 9,000-13,000 mPa·s.
3 . The hydroxyl-terminated polyester resin according to claim 1 , wherein the catalyst is an organic tin catalyst.
4 . A coating comprising the hydroxyl-terminated polyester resin of claim 1 .
5 . A method for preparing the hydroxyl-terminated polyester resin according to claim 1 , comprising the following steps of:
(a) carrying out a polycondensation reaction of the diol, dibasic acid, glycidyl tertcarbonate, and catalyst in an inert atmosphere to obtain a primary polymer;
(b) when the acid value of the primary polymer obtained in step (a) is 10-25 mgKOH/g, vacuumizing and then continuing the polycondensation reaction to obtain a condensation polymer; and
(c) when the acid value of the condensation polymer obtained in step (b) is 8-15 mgKOH/mg, carrying out a hydroxylation reaction until the acid value of the product obtained by the hydroxylation reaction is 1-8 mgKOH/g and the hydroxyl value of the product is 20-30 mgKOH/g, at this moment, adding an antioxidant, and then mixing to obtain the hydroxyl-terminated polyester resin.
6 . The method for preparing the hydroxyl-terminated polyester resin according to claim 5 , wherein the degree of vacuum of the vacuumizing in step (b) is in a range of 0.08 MPa to 0.1 MPa.
7 . A coating comprising the hydroxyl-terminated polyester resin prepared according to the method of claim 5 .
8 . The method for preparing the hydroxyl-terminated polyester resin of claim 5 , wherein the catalyst is an organic tin catalyst.
9 . The method for preparing the hydroxyl-terminated polyester resin of claim 5 , wherein the temperature of the polycondensation reaction of step (a) is in a range of 230° C. to 240° C.
10 . The method for preparing the hydroxyl-terminated polyester resin of claim 5 , wherein the time of the polycondensation reaction of step (a) is in a range of 3 hours to 5 hours.
11 . The method for preparing the hydroxyl-terminated polyester resin of claim 5 , wherein the time of the polycondensation reaction of step (b) is in a range of 50 minutes to 120 minutes.
12 . The method for preparing the hydroxyl-terminated polyester resin of claim 5 , wherein the temperature of the hydroxylation reaction in step (c) is in a range of 215° C. to 230° C. and the time of the hydroxylation reaction in step (c) is in a range of 1 hour to 3 hours.
13 . The method for preparing the hydroxyl-terminated polyester resin of claim 5 , wherein the temperature of the mixing in step (c) is in a range of 200° C. to 230° C. and the time of the mixing in step (c) is in a range of 10 minutes to 40 minutes.