JPS604209B2 - Polyester manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing polyester.

The purpose is to provide a polyester having excellent transparency, flame retardancy, chemical resistance, mechanical performance, and heat resistance.

Traditionally, polyethylene terephthalate has been used in a variety of applications due to its excellent mechanical performance, chemical resistance, and dimensional stability, such as:
Used in fibers, films, molded products, etc.

However, this polyester is easily flammable and has an extremely high crystallization rate, so when a molded product with a thickness of, for example, a reed inch is obtained, crystallization occurs and only an opaque product is obtained, requiring transparency. It is unsuitable for this purpose.

On the other hand, various attempts have been made in the past to reduce the crystallization rate; for example, 20 to 75 mol% of neoventrene glycol was used in Japanese Patent Publication No. 38-10036, and isophthalic brewing ingredient was used in Hakama Kosho No. 34-3238. 5-35
Although it has been proposed to copolymerize polyesters with improved transparency in this way, they are also easily flammable, and if various halides are blended to make them flammable, transparent molded products can be produced. You won't be able to get it. For example, polyethylene terephthalate copolymerized with a dibromoterephthalic acid component is also known, but in this case, if the dibromoterephthalic acid component is copolymerized to provide sufficient flame retardancy, the heat resistance of the polyester will increase accordingly. It is unfavorable because it deteriorates.

The present inventor has conducted extensive studies on polyester that has good transparency, flame retardancy, and heat resistance, and found that when a certain halide is added and reacted during the production of polyethylene terephthalate, the transparency, flame retardance, and heat resistance are improved. It has been discovered that polyester with excellent heat resistance can be obtained, and the present invention has been achieved. That is, the present invention provides the following general formula at any stage of the reaction when producing a polyester by melting and reacting a basic acid mainly composed of terephthalic acid and/or its ester-forming ghost conductor with a glycol mainly composed of ethylene glycol. (
1) However, in the formula, × is CI or Br; a, b are integers of 0 to 4 (however, a + b ZI); R,, R2 are C, ~6 alkyl groups (R,, R2 are not bonded) ): R3 is C
, ~6 alkyl group or C6~,2 aryl group, haloaryl group; R4 is day or a carbonate compound represented by an integer of 1 or more in proportion to 1 to 6 of the total brewing components.
This is a method for producing polyester, which is characterized by adding 7% by weight and reacting at least until the product becomes transparent.

In the present invention, terephthalic acid is used as the main brewing ingredient, and its amount is preferably 80 mol% or more, more preferably 90 mol% or more of the total brewing ingredients.

20 mol% or less of the total brewing components, more preferably 10 mol%
One or more other dibasic acids such as isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxychetane dicarboxylic acid, adipic acid, sebacic acid, etc. may be used in the following proportions. Also, oxycarboxylic acids such as oxybenzoic acid may be used. The ester-forming derivative in the present invention is an alkyl ester having 1 to 6 carbon atoms, an aryl ester having 6 to 12 carbon atoms, or an acid chloride.
Further, in the present invention, ethylene glycol is used as the main glycol component, and preferably 70 mol% or more, more preferably 80 mol% or more is ethylene glycol. In addition, 30 mol% or less of the total glycol, more preferably 2
One or more other glycol components such as propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neobenzene glycol, cyclohexane dimethylol, etc. may be used in a proportion of 0 mol % or less. Further, it is preferable that the total glycol component used in the reaction is 150 mol% or more based on the total brewing component. Preferred examples of the carbonate compound represented by the general formula (1) used in the present invention include the general formula (
2 of the compound in which a and b in 1) are each 2.
2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 1,1-bis(315-
Dibromo-4-hyde.

xyphenyl) cyclohexane, 1,1-bis(3,5
A polycarbonate derived from -dichloro-4-hydroxyphenyl)cyclohexane, etc., and having an aryl group (eg, phenyl group, tribromophenyl group) at the end is preferred. Further, the degree of polymerization of the carbonate compound is 1 or more, and the upper limit is 4. The amount of the carbonate compound used is 1 to 7% by weight based on the total brewing ingredients. If it is less than 1% by weight, a product with sufficiently excellent flame retardancy and transparency cannot be obtained, and if it exceeds 7% by weight, a product with a high degree of polymerization cannot be obtained, which is not preferable.

A particularly preferred amount is between 5 and 5% by weight. The carbonate compound may be added at any stage during the melt reaction of the terephthalic brewing component and the ethylene glycol component; for example, it may be added at the same time during reaction preparation, during the polymerization reaction, or during the polymerization of polyester. There is a method of carrying out a mixed reaction afterwards. In the method of the present invention, it is necessary not only to add and mix the carbonate compound, but also to react at least until the product becomes transparent. For example, if the carbonate compound is simply added and mixed with polyethylene terephthalate, the product becomes opaque, which is not preferable. In the production of the present invention, additives such as catalysts, stabilizers, pigments, optical brighteners, colorants, etc. which are commonly used in polyester polymerization can be used without any problem. As is clear from the examples below, the polyester obtained by the present invention has excellent transparency, flame retardancy, and heat resistance, and is an excellent material for various molded products, films, fibers, etc. In the Examples, all "parts" are "r parts by weight", and the intrinsic viscosity was measured at 3500 in orthochlorophenol.

In addition, the limiting oxygen index (abbreviated as LOI), which indicates flame retardancy, is AST.
According to the method of MD-2863-70, the heat distortion temperature is
This is a value measured by the method of ASTM D-648. Example 1 194 parts of dimethyl terephthalate was placed in a flask with a rectification column,
13 parts of ethylene glycol and 0.068 parts of titanium tetrabutoxide were charged, heated to 160 to 230 qo, and methanol produced by the reaction was removed from the system.
e) The reaction was continued until the theoretical amount of methanol was produced.

Next, the reactant was transferred to a flask equipped with a flywheel, 28.2 parts of polycarbonate having the following structure was added, and the reaction was carried out at 27,500 yen under normal pressure for 30 minutes, and then the pressure inside the system was gradually reduced to 15
After a minute, the pressure was reduced to about 0.5 Hg and the reaction was continued for 60 minutes. The obtained polymer had an intrinsic viscosity of 0.72 and a melting point of 2.
It was 4900. Next, this polymer is crushed into chips, dried, and then the cylinder temperature is 25,000 and the mold temperature is 30.
A molded piece for LOI test (inch thickness) and a test piece for heat distortion temperature measurement (inch thickness) were injection molded at qo. All of the obtained molded products were transparent. Furthermore, when the LO1 and heat distortion temperature of these molded products were measured, they were 27.5% and 7400, respectively. Comparative Example 1 In the method of Example 1, polymerization was carried out without adding any polycarbonate, and the same amount of the polycarbonate used in the method of Example 1 was mixed with the obtained polyethylene terephthalate (intrinsic viscosity 0.75). (275° C., 5 minutes), and the resulting mixture (melting point: 260 oo) was injection molded in the same manner as in Example 1. All of the molded products obtained were opaque.

Also, the LOI of this molded product is 25.5%, and the heat distortion temperature is 69.
℃ and both were lower than those of the present invention. Comparative Example 2 In the method of Example 1, 2,5-dibromo terephthalic acid dimethyl ester was added in the same amount as the polycarbonate in the method of Example 1 at the time of reaction preparation, and the polycarbonate was not used. The reaction was carried out in exactly the same manner as in method 1,
A polymer was obtained.

The resulting polymer has an intrinsic viscosity of 0.71 and a melting point of 237°C.
Met. Next, injection molding was performed using this polymer under the same conditions as in Example 1. All of the obtained molded products were transparent, but their LOI was 25.0% and their heat distortion temperature was 6400, both of which were lower than those of Example 1. Also, in order to make the flame retardance comparable to that of the molded product obtained by the method of Example 1, 47% of dimethyl 2,5-dibromo terephthalate was added. Using the anchor, conduct the reaction in the same manner until the intrinsic viscosity is 0.
A polymer having a melting point of 22,300° C. was obtained, and then injection molded and the physical properties of the molded product were measured. The LOI was 27.0%, but the heat distortion temperature was found to be even lower at 61° C., which was undesirable.

Example 2 Into a flask similar to the method of Example 1, 194 parts of dimethyl terephthalate, 13 parts of ethylene glycol, 63.7 parts of polycarbonate having the following structure, and 0.1 parts of manganese acetate were charged and heated to 160 to 240°C. The methanol produced by the reaction was then removed from the system.

e) After the theoretical amount of methanol was produced, the reactants were transferred to a reactor equipped with a Takaazusa machine, and 0.07% of trimethyl phosphate was added.
After adding 0.15 parts of antimony trioxide, the mixture was heated to 28,000 yen for 30 minutes under normal pressure, and then the pressure inside the system was gradually reduced to about 0.5 parts of Hg after 15 minutes, and the reaction was continued for an additional 90 minutes. The resulting polymer has an intrinsic viscosity of 0.60 and a melting point of 242
It was ℃. This polymer was then injection molded under the same conditions as in Example 1. All of the molded products obtained had excellent transparency, LO1 of 31.0%, and heat distortion temperature of 78.
It was oC. Example 3 Polyethylene terephthalate 192 with intrinsic viscosity 0.65
Polycarbonate represented by the following formula: 42.7
The mixture was charged into a reactor and reacted at 280 oo for 15 minutes under normal pressure, and then for 3 hours under reduced pressure of about 0.5 side Hg.

Claims (1)

[Scope of Claims] 1. When producing a polyester by melt-reacting a dibasic acid mainly consisting of terephthalic acid and/or its ester-forming derivative with a glycol mainly consisting of ethylene glycol, at any stage of the reaction. The following general formula (I) ▲ Formula,
There are chemical formulas, tables, etc. ▼ Carbonate compounds represented by 1 to 1 to total acid components
A method for producing polyester, which comprises adding 70 wt% and reacting at least until the product becomes transparent.