JPS5921889B2 - Polyester manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for making stabilized polyesters.

More specifically, the present invention relates to a method for improving the stability of certain polyesters at high temperatures. It is well known that polytrimethylene terephthalate, polytrimethylene naphthalene-2,6-dicarboxylate and the like are useful as molding materials as aromatic polyesters containing trimethylene glycol as a glycol component. However, polyesters containing trimethylene glycol as the main glycol component have disadvantages in that they have poor thermal stability and poor color tone compared to other aromatic polyesters such as polyethylene terephthalate and polytetramethylene terephthalate. As a result of repeated research in order to eliminate these drawbacks, the present inventor discovered that such drawbacks could be improved by incorporating a specific stabilizer into polyester, and arrived at the method of the present invention. That is, when producing a polyester containing aromatic dicarboxylic acid as the main acid component and trimethylene glycol as the main glycol component, the present invention uses a titanium compound as a catalyst in the process of polycondensing the polyester and stabilizes the polyester. As an agent, the general formula HCMoR3na11"OH [wherein R4 and R2 are monovalent aliphatic groups having 1 to 8 carbon atoms, R3 is a divalent hydrocarbon residue having 1 to 8 carbon atoms, and n is o This is a method for producing a polyester, which is characterized by adding a small proportion of a phosphonic acid ester represented by the following formula.

The polyester used in the present invention is a polyester containing aromatic dicarboxylic acid as the main acid component and trimethylene glycol as the main glycol component.

Here, aromatic dicarboxylic acids include, for example, terephthalic acid, isophthalic acid, phthalic acid, diphenyl-4,4'
-Dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, naphthalene-1
, 5-dicarboxylic acid, diphenoxyethane-4,4'
Dicarboxylic acids such as -dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid and diphenyl ether-4,4'-dicarboxylic acid can be mentioned.

The polyester of the present invention is a polyester having the above-mentioned aromatic dicarboxylic acid as the main acid component and trimethylene glycol as the main glycol component. Malonic acid, 1,1-dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, decamethylene dicarboxylic acid, ω-oxycaproic acid, P-oxybenzoic acid, P-β-hydroxyethoxybenzoic acid in the range Acid components such as ethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, hydroquinone, bisphenol-A, 4,4'-dioxydiphenyl, 4,4'-dioxydifhenyl enyl sulfone,
It may also be a copolymerized polyester obtained by copolymerizing a glycol component such as 4,4'-bis-β-hydroxyethoxybenzene.

In the method of the present invention, polyester can be produced by a conventionally known method using a titanium compound as a polymerization catalyst.

Conventionally known transesterification catalysts for lower alkyl esters of dicarboxylic acids and glycols include compounds containing sodium, potassium, magnesium, calcium, zinc, strontium, titanium, zirconium, manganese, and cobalt (including titanium compounds). of a titanium compound as a polymerization catalyst. This is a method of heating polymerization at 200 to 260° C. under reduced pressure in the presence of a compound.

Here, titanium compounds that are conventionally known as polyester polymerization catalysts can be used.

Titanium compounds generally include tetraalkyl titanate, tetraaryl titanate, titanyl oxalate salts, titanyl oxalate, chelate compounds containing titanium, tetracarboxylate of titanium, etc., and specifically, tetraethyl titanate. Examples include titanate, tetrabutyl titanate, tetrapropyl titanate, tetraphenyl titanate, or partial hydrolysates thereof, titanylammonium oxalate, potassium titanyl oxalate, titanium trisacetylacetonate, and the like. Further, the amount of the titanium compound used in producing the polyester is 0.0% based on the total acid components constituting the polyester.
0.005 to 0.5 mol% is preferred, particularly preferably 0.005 to 0.5 mol%.
01 to 0.3 mol%. If it is less than 0.005 mol%, the effect as a catalyst will not be sufficient, and if it exceeds 0.5 mol%, the thermal stability of the resulting polyester will deteriorate, which is not preferable.

Therefore, it is preferable to use a titanium compound in a range of 0.01 to 0.3 mol % in the polymerization reaction. The stabilizer of the process of the invention is an ester of phosphonic acid of the general formula.

Here, examples of the aliphatic groups of Rl and R of the phosphonic acid shown in the general formula include methyl group, ethyl group, isopropyl group, secondary butyl group, tertiary butyl group, and 1,1-dimethylpropyl group. 1,2-dimethylpropyl group, 1-methylbutyl group, 1,1-dimethyl-3,3-dimethylbutyl group, and the like. The hydrocarbon residues of R3 include aliphatic groups such as methylene group, ethylene group, ethylidene group, trimethylene group, propylene group, butylene group, and neopentylene group, and divalent carbonized groups including aromatic nuclei such as phenylene group and xylylene group. Examples include hydrogen residues.

Here, n is 0 or 1. In addition, in the present invention, R
Both l and R2 can be hydrogen atoms, but Rl, R
It is preferable that at least one of 2 is an aliphatic group, and it is particularly preferable that the total carbon number of Rl and R2 is 4 or less. 0 The stabilizer of the present invention is an ester of phosphonic acid represented by the above general formula. is used.

Here, the ester is an ester of a hydroxy compound such as a known monohydroxy compound, dihydroxy compound, trihydroxy compound, or tetrahydroxy compound conventionally used as a polyester raw material or intermediate raw material and a phosphonic acid represented by the above general formula. Here, monohydroxy compounds include alcohols with carbon atoms of 20 or less such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, cyclohexanol, benzyl alcohol, etc., phenol, cresol, xylenol, butyl phenol,
Phenols such as octylphenol, naphthol, monochlorophenol, and dipromphenol can be mentioned.

Examples of dihydroxy compounds include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, hydroquinone, and bisphenol Al4,4'-dioxy having 20 or less carbon atoms. Diphenyl, 4,4'-
Examples include dioxydiphenyl sulfone, 4,4'-bis-β-hydroxyethoxybenzene, and the like.

Examples of trihydroxy compounds and tetrahydroxy compounds include those having 20 or less carbon atoms, such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. The ester of the phosphonic acid and the polyhydroxy compound of the general formula of the present invention is, for example, the ester of the phosphonic acid and the monohydroxy compound, the dihydroxy compound (1 to 2 times the mole), the trihydroxy compound (2/3 to 2 moles), and the ester of the phosphonic acid and the monohydroxy compound. It can be easily produced by adding a tetrahydroxy compound (0.5 to 2 moles) and carrying out a transesterification reaction. phosphonic acid of the invention,
Preferred esters are esters of the phosphonic acid and monohydroxy compounds or dihydroxy compounds (among them aliphatic dihydroxy compounds), and more preferred are esters of the phosphonic acid and trimethylene glycol.

In the method of the present invention, the stabilizer may be added at any stage from the initial stage of polymerization of the polyester to the completion of molding of the polyester.

However, the preferable addition time is from the polyester polymerization stage to the end of polymerization (including the end of polymerization).It is added at the polyester polymerization stage, and after addition, the intrinsic viscosity of the polyester becomes equal to or higher than the intrinsic viscosity of the polyester at the time of addition. It is more preferable to carry out the melt polymerization under reduced pressure up to In this way, a polyester with better color tone and better heat stability can be obtained. A particularly preferable time for adding the stabilizer is when polyester is produced by the transesterification method as described above, after the transesterification reaction and until the intrinsic viscosity of the polyester reaches 0.5. A stabilizer is added, and the polyester is further melt-polymerized until the intrinsic viscosity of the polyester reaches 0.55 or more. The polyester of the present invention can also be melt-polymerized, turned into chips, and solid-phase polymerized at 180 to 220 DEG C. under reduced pressure or in an inert gas stream of nitrogen or the like.

In this way, a polyester with an even higher degree of polymerization can be obtained. The amount of the specific stabilizer of the present invention added may be in the range of 0.005 to 5 mol%, but preferably in the range of 0.01 to 0.5 mol%, based on the total acid components constituting the polyester. Furthermore, considering the polymerization rate of polyester after the addition of such a stabilizer, it is 0.1% for the titanium catalyst used.
It is particularly preferred that the amount is 2 to 2 times the mole.

Compared to conventional stabilizers, the stabilizer used in the method of the present invention hardly deactivates the polymerization catalyst, and even by using such a stabilizer, a polyester with a high degree of polymerization can be easily obtained. If too much is used, the polymerization rate tends to decrease, which is not preferable.

In the method of the present invention, glass fibers, titanium oxide, conventionally known inorganic fillers, flame retardants, etc. may be added in addition to the above-mentioned stabilizers.

The method of the present invention will be explained in detail below with reference to Examples.

In this specification, the intrinsic viscosity is defined as the intrinsic viscosity of the polymer mixed with phenol and tetrachloroethane (mixing ratio 6:4) at 140°C.
It was determined by dissolving in 0 minutes and measuring at 35°C. Moreover, parts mean parts by weight. Examples 1 to 7, Comparative Example 1 97 parts of dimethyl terephthalate, 84 parts of trimethylene glycol, 0.08 parts of titanium tetrabutoxide
The mixture was heated to 160-230°C to distill off methanol produced as a result of the transesterification reaction.

Thereafter, 0.05 mol% of the various stabilizers listed in Table 1 was added, heated to 240°C, reacted for 15 minutes in a nitrogen stream, and then gradually reduced pressure to the same temperature and 0.3 to 0.4 m Ht.
Polymerization was carried out for 200 minutes.

The intrinsic viscosity of the polyester was about 0.75. Separately, as a comparative example, an example in which no stabilizer was added (other reaction conditions were the same as in the example) was also listed in the table.

Claims (1)

[Claims] 1. When producing a polyester containing aromatic dicarboxylic acid as the main acid component and trimethylene glycol as the main glycol component, a titanium compound is used as a catalyst in the process of polycondensing the polyester, and the polyester is As a stabilizer, there are general formulas ▲ mathematical formulas, chemical formulas, tables, etc. residue,
n is 0 or 1. ] A method for producing polyester, which comprises adding 0.005 to 5 mol % of the phosphonic acid ester represented by the above acid component.