JPS59129228A - Production of copolyester resin - Google Patents

Abstract

PURPOSE:To produce the titled resin soluble in solvents and excellent in storage stability, by reacting a dicarboxylic acid material with an excess of a diol material until a specified acid value is obtained and, after removing the excess glycol, polycondensing the materials. CONSTITUTION:A dicarboxylic acid component comprising 20-80mol% terephthalic acid and 80-20mol% other dicarboxylic acids and a diol component comprising 20-80mol% neopentyl glycol and 80-20mol% other diols are fed in amounts to provide a B/A molar ratio of 1.3-4.0/1.0, and the mixture is esterified to obtain an acid value of below 400 equivalent/10<6>g and, after removing the excess glycol in vacuum, polycondensed. EFFECT:It is possible to obtain a copolyester which is easily soluble in solvents, and excellent in storage stability of its solution. USE:Binders for paints and inks, and adhesives

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a copolyester face fat which is soluble in a solvent and which has poor shelf life after being dissolved in the solvent.

Conventionally, after copolymerized polyester resin is dissolved in a solvent,
Paint, ink binder, or each square film,
It has been used as an adhesive for metals, etc. In heavy-duty applications, copolymerized polyester resins are sometimes left to stand for about six months to one year after being dissolved in a solvent, which poses the problem that substances insoluble in the solvent precipitate. Precipitation of solvent-insoluble substances is caused by the dispersibility of pigments,
This has a negative effect on coating properties, and there has been a strong demand for improvement.

In view of these circumstances, the present inventors conducted extensive research and found that the storage stability of polyester resin solutions is closely related to the degree of reaction of the initial esterification of aromatic dicarboxylic acids or aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and diols. We have discovered that there is a relationship between the two, and have arrived at the present invention.

The present invention uses terephthalene 20 to 8 as the dicarboxylic acid component.
0 mol% and other dicarboxes in order 80-20 mol%
In a method for producing a copolyester resin consisting of 20 to 80 mol% of neopentyl glycol and 80 to 20 mol% of other diols as diol components, 1 dicarboxylic acid raw material and an excess amount of diol raw material are subjected to an initial esterification reaction. This is a method for producing a copolymerized polyester resin, characterized in that the esterification reaction is carried out until the acid value of

The initial esterification reaction in the present invention is a reaction between a dicarboxylic acid raw material and a diol raw material, and is usually carried out under normal pressure or increased pressure.

In the present invention, the solvent-soluble copolyester resin contains terephthalic acid as a dicarboxylic acid component [20 to 80 mol%] and 80 to 20 mol% of other dicarboxylic acid components.
, neopentyl glycol 20-8 as a diol component
0 mol%Oyohiso's other diol components 80-20 mol%
Consists of. Other dicarboxylic acids include aromatic dicarboxylic acids such as isophthalic acid, ortho-7thalic acid, 1,5-7thalenedicarboxylic acid, 414'-cyphelic acid, 5-sodium sulfoisophthalic acid, cono-7thalic acid, Examples include adipic acid, azelaic acid, sebacic acid, and dodecanedioic acid. On the other hand, (1) diol components other than neopentyl glycol include aliphatic diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-bentanediol, and 1,6-hexanediol;
, 4-cyclohexanediol, etc., aromatic ring-containing diols such as xylylene glycol, etc.0 In addition, trifunctional diols may be used within the range of 20 mol% or less of the total dicarbonate or total diol component. The above polycarboxylic acids or polyols can be used. Examples of polycarboxylic acids having 3' or higher functionality include trimellitic acid, pyromellitic acid, etc., and examples of polyols having 3 or more functions include glycerin, trimethylolethane,
Trimethylolethane, pentaerythritol and the like can be mentioned. In addition, if it is less than 30 mol% of the total dicarbonate components, p-hydroxyethoxyammonium, aromatic acid,
Hydroxycarboxylic acids such as hydroxypivalic acid can be used.

The copolymerized polyester resin of the present invention has 20 to 80 mol% of terephthalic acid and 80 to 20 mol% of other dicarboxylic acids as a dicarboxylic acid component, and 20 to 80 mol% of neopentyl glycol and 80 to 20 mol% of other diols as a diol component. However, if the content of terephthalic acid, other dicarboxylic acids, neopentyl glycol, and other diols is less than 20 mol% or exceeds 80 mol%, respectively, the solubility in solvents will be poor and the storage stability will be poor. Become.

In the present invention, terephthalic acid and neopentyl glycol are essential components, and the A esterification reaction is carried out using a total diol/initially charged dicarboxylic acid ratio of 1,3 to 4,0/1.0 (mole ratio), preferably 1. 5-3.0/l. 0 (molar ratio), and the acid value is 400 equivalents 7106 p or less, preferably 2
It is characterized in that after reducing the amount to 00 equivalent/106f or less, a condensation reaction under reduced pressure is carried out.

If the polycondensation reaction is carried out at a stage where the acid value exceeds 400/10'I, the resulting copolyester resin will have poor storage stability after being dissolved in a solvent.

In producing the copolymerized polyester resin of the present invention, known polymerization catalysts can be used, but desirably,
The catalyst is a titanium-based catalyst, and most preferably tetrabutoxytitanium.

In the field of paints and adhesives, the solvent used in the present invention refers to pan-thyl ethyl ketone, methyl isobutyl ketone, cyclohexane,
Ketones such as isophorone, ethyl acetate, butyl acetate,
Examples include esters such as cellosolve acetate, and cyclic ethers such as tetrahydrofuran and dioxane.

The copolymerized polyester resin of the present invention can be used alone or in combination with other curing agents for binders for paints, inks, etc., and adhesives for laminates, etc. The copolyester resin of the present invention can also be used as a raw material for known modified resins such as polyurethane resins, polyester acrylates, and polyester-urethane-acrylates.

The present invention relates to a method for producing a copolyester resin that is easily soluble in a solvent and has excellent storage stability, and will be specifically explained below using actual examples.

In the examples, parts simply indicate parts by weight.

Example L Terephthal J 774.7 parts, isophthalic acid 74.7 parts,
20.2 parts of Sebacin I, 74°4 parts of ethylene glycol, 83.2 parts of neopentyl glycol, and 0.07 parts of tetrabutoxytitanium were placed in an autoclave.
The esterification reaction was carried out at 230°C for 2 hours and at 240°C for 1.5 hours. A sample of the system was taken and the acid value was measured, and it was found to be 160 equivalents/1. It was o61. Next, the pressure inside the reaction system was reduced to 5 m Hg in 0.65 hours, and the pressure was reduced to 250"
The polycondensation reaction was carried out at C for 0.5 hours under conditions of 0.2 to 0.4 μH9.

The obtained copolymerized polyester resin (A) was pale yellow and transparent, and had a reduced viscosity of 0642. When the composition of the copolymerized polyester resin (A) was analyzed by NMR, it was found that 4-5 mol% of terephthalate, 45 mol% of isophthalic acid, 10 mol% of sebacin powder, 48 mol% of ethylene glycol,
The neopentyl glycol content was 52 mol%. Copolymerized polyester resin (A) was mixed with solvent methyl ethyl ketone/toluene-1/l (
When the solution was dissolved at 4°C (weight ratio) and allowed to stand for 6 months at 4'C, it appeared transparent with no change in appearance and had excellent storage stability.

Comparative Example L A copolymerized polyester resin (
B) was polymerized. Acid value after esterification reaction is 480 equivalent f
fi/1 o'y, and the reduced viscosity of the copolyester resin (B) was 0.46.

Methyl ethyl ketone/toluene-1/
1 (weight ratio) to a solid content concentration of 40% by weight, and heated at 4°C.
When it was stored for three months, insoluble substances began to precipitate.
Within six months, transparency had completely disappeared.

Examples Z and 4 Copolyester resins (O) to (ID) were polymerized in the same manner as in Example 1. Table 1 shows the reduced viscosity of each resin and the low price after esterification reaction.

Furthermore, Table 2 shows the storage stability when each resin was dissolved in a solvent and stored at 4'C.

Comparative Examples 2 to 6 Copolymerized polyester resins (F) to (J) were polymerized in the same manner as in Comparative Example 1 or Example 1. Table 1 shows the composition, reduced viscosity, and oxidation after the esterification reaction of each resin.

Table 2 shows the storage stability of each resin dissolved in a solvent and stored at 4°C.

As is clear from Tables 1 and 2, the copolyester resin obtained by the method of the present invention has excellent solution storage stability.

Patent applicant: Toyobo Co., Ltd.

Claims (1)

[Claims] Terephthal 1120-80 mol% and other dicarboxylic V8O-20 mol% Karasu as dicarboxylic acid component, Neopentyl glycol 20-20 mol% as diol component
In a method for producing a copolymerized polyester/l/resin consisting of 80 mol% of other diols and 80 to 20 mol% of other diols, the acid value after an initial esterification reaction of a dicarbonate plate raw material and an excess amount of diol raw materials is 400 equivalents/4o6g. 1. A method for producing a copolymerized polyester resin, which comprises carrying out an esterification reaction until the following is achieved, and then removing an excess amount of glycol under reduced pressure to perform polycondensation.