JP2000159984A - Polyester composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester composition good in thermal stability, transparency and polymer color tone, excellent in molding/forming processabilities, and useful for fibers, etc., by including specific phosphorus compound(s) and through polycondensation reaction without decline in the reactivity. SOLUTION: This polyester composition is obtained by including phosphorus compound(s) of formula I and/or II [R1 and R2 are each H, a 1-15C alkyl, phenyl, or the like; R3 is phenyl or a trivalent organic group; R4 and R5 are each carboxy, a hydroxyalkyl, or the like; R6 is (CH2)n (n is 2-4)] so as to be 20-1,000 ppm in the content based on the polyester polymer (calculated as phosphorus atom); wherein if an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol, or a low-molecular polyester oligomer is used as a starting material, it is preferable to incorporate the phosphorus compound(s) in the starting material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyester composition and a method for producing the polyester composition. More specifically, the present invention relates to a polyester composition having good heat stability, transparency and polymer color tone and excellent moldability, and a method for producing the polyester composition.

[0002]

2. Description of the Related Art Due to its excellent properties, polyesters are widely used in various fields including fibers, films and bottles. Among them, polyethylene terephthalate is excellent in mechanical strength, chemical properties, dimensional stability and the like, and is suitably used.

[0003] Generally, polyethylene terephthalate is produced from terephthalic acid or an ester-forming derivative thereof and ethylene glycol. In a commercial process for producing a polymer having a high molecular weight, the reaction proceeds smoothly and quickly to economically make polyester. It is necessary to use a catalyst to obtain the compound, and many compounds have been proposed as catalysts. However, most of the known catalysts promote decomposition and side reactions due to the high reaction temperature during the production of polyester, deteriorating the color tone and ether bonds in the polymer,
Undesirable results such as an increase in the amount of terminal carboxyl groups are caused. It is well known that the presence of a phosphorus compound during a polycondensation reaction is effective for suppressing such decomposition and side reactions, and phosphoric acid, phosphorous acid and esters thereof are usually used. Have been. However, the use of these phosphoric acids, phosphorous acids and their esters is still insufficient to suppress the decomposition and side reactions of the polyester, prevent coloring, and improve the thermal stability during melting. . In addition, when a relatively large amount of a phosphorus compound such as phosphoric acid, phosphorous acid or their ester is contained, the activity of the catalyst is also suppressed, causing a decrease in polycondensation reactivity or causing a decrease in the production of polyester. There were problems such as generation of insoluble foreign matter with the used catalyst.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, not to decrease the polycondensation reactivity, to have good thermal stability, transparency and polymer color tone, and to be excellent in molding processability. An object of the present invention is to provide a polyester composition and a method for producing the polyester composition.

[0005]

The object of the present invention is attained by a polyester composition comprising a phosphorus compound represented by the formula (1) and / or (2).

[0006]

Embedded image

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester of the present invention is a polymer synthesized from a dicarboxylic acid or an ester-forming derivative thereof and a diol, and can be used as molded articles such as fibers, films and bottles.

Specific examples of such polyesters include, for example, polyethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene 2,6-naphthalenedicarboxylate, and polyethylene-1,2-bis (2
-Chlorophenoxy) ethane-4,4'-dicarboxylate. The present invention is suitable for the most widely used polyethylene terephthalate or a polyester copolymer mainly composed of polyethylene terephthalate.

These polyesters include, as copolymerization components, dicarboxylic acids such as adipic acid, isophthalic acid, sebacic acid, phthalic acid, 4,4'-diphenyldicarboxylic acid, and ester-forming derivatives thereof, polyethylene glycol, diethylene glycol. And dioxy compounds such as hexamethylene glycol, neopentyl glycol and polypropylene glycol; oxycarboxylic acids such as p- (β-oxyethoxy) benzoic acid; and ester-forming derivatives thereof.

The phosphorus compound in the present invention is represented by the formulas (1) and (2).

[0011]

Embedded image Specific examples of the phosphorus compound represented by the general formula (1) include 2,5-dicarboxyphenylphosphonic acid (hereinafter, referred to as 2,5-DCPPA), 2,5-dicarboxyphenylphosphonic acid monomethyl ester, , 5-
Dicarboxyphenylphosphonic acid dimethyl ester (hereinafter referred to as 2,5-DCPPDM), 2,5-dicarboxyphenylphosphonic acid monoethyl ester, 2,5-dicarboxyphenylphosphonic acid diethyl ester,
5-dicarboxyphenylphosphonic acid diphenyl ester, 2,5-dicarboxyphenylphosphonic acid diethylene glycol ester (hereinafter 2,5-DCPPDEG
2,5-dicarboxyphenylphosphonic acid dipropylene glycol ester, 2,5-dicarboxyphenylphosphonic acid dibutylene glycol ester,
2,5-dimethylcarboxyphenylphosphonic acid (hereinafter referred to as 2,5-DMCPPA), 2,5-dimethylcarboxyphenylphosphonic acid monomethyl ester, 2,5
-Dimethylcarboxyphenylphosphonic acid dimethyl ester, 2,5-dimethylcarboxyphenylphosphonic acid monoethyl ester, 2,5-dimethylcarboxyphenylphosphonic acid diethyl ester, 2,5-dimethylcarboxyphenylphosphonic acid diphenyl ester, 2,
5-dimethylcarboxyphenylphosphonic acid diethylene glycol ester, 2,5-dimethylcarboxyphenylphosphonic acid dipropylene glycol ester,
2,5-dimethylcarboxyphenylphosphonic acid dibutylene glycol ester, 3,5-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid monomethyl ester, 3,5-dicarboxyphenylphosphonic acid dimethyl ester 3,5-DCPP
DM), 3,5-dicarboxyphenylphosphonic acid monoethyl ester, 3,5-dicarboxyphenylphosphonic acid diethyl ester, 3,5-dicarboxyphenylphosphonic acid diphenyl ester, 3,5-dicarboxyphenylphosphonic acid Diethylene glycol ester, 3,5-dicarboxyphenylphosphonic acid dipropylene glycol ester, 3,5-dicarboxyphenylphosphonic acid dibutylene glycol ester, 3,
5-dimethylcarboxyphenylphosphonic acid, 3,5-
Dimethylcarboxyphenylphosphonic acid monomethyl ester, 3,5-dimethylcarboxyphenylphosphonic acid dimethyl ester, 3,5-dimethylcarboxyphenylphosphonic acid monoethyl ester, 3,5-dimethylcarboxyphenylphosphonic acid diethyl ester (hereinafter 3,5- DMCPDE), 3,5-dimethylcarboxyphenylphosphonic acid diphenyl ester,
5-dimethylcarboxyphenylphosphonic acid diethylene glycol ester, 3,5-dimethylcarboxyphenylphosphonic acid dipropylene glycol ester,
3,5-dimethylcarboxyphenylphosphonic acid dibutylene glycol ester and the like.

Specific examples of the phosphorus compound represented by the formula (2) include cyclic esters of 2,5-dicarboxyphenylphosphonic acid with ethylene glycol, propylene glycol or butylene glycol; Cyclic ester of carboxyphenylphosphonic acid and ethylene glycol, propylene glycol or butylene glycol, 2,5-dimethylcarboxyphenylphosphonic acid and ethylene glycol, propylene glycol,
Or cyclic ester with butylene glycol, 3,5-
And cyclic esters of dimethylcarboxyphenylphosphonic acid with ethylene glycol, propylene glycol, or butylene glycol. However,
The specific phosphorus compound of the present invention may be any compound represented by the general formulas (1) and (2), and is not limited to the above specific examples. These phosphorus compounds may be used alone or in combination of two or more. Other phosphorus compounds such as phosphoric acid, phosphorous acid and derivatives thereof, which are usually used as a coloring inhibitor for polyesters, may be used in the present invention. There is no problem if they are added together as long as they meet the purpose. When adding,
It may be added as it is, may be dispersed or dissolved in a suitable solvent such as glycol, or may be heat-treated in glycol. Among the compounds represented by the formula (1), 2,5-DCPPA, 2,5-DMCPP
A, 2,5-DCPPDM, 3,5-DCPPA, 3,
5-DMCPPA and 3,5-DCPPDM are preferably used, but 2,5-DCPPA and 3,5-DCPPA
Is more preferably used.

Although the content of the phosphorus compound of the present invention is not particularly limited, it is 20 to 1000 ppm, more preferably 30 to 1000 ppm by weight relative to the polymer in terms of phosphorus atom.
It is 800 ppm, more preferably 50 to 500 ppm. If the content is less than 20 ppm, the effect of improving the thermal stability, transparency and color tone of the polyester tends to be insufficient, and if it exceeds 1000 ppm, the activity of the polycondensation catalyst is inhibited or Unnecessary foreign matter may be generated, and an increase in filtration pressure during molding may be observed.

When the phosphorus compound of the present invention is used, the color tone of the polymer is improved, and since the processability is excellent, problems such as an increase in filtration pressure and breakage of the thread are eliminated, so that it is suitable for fibers.

The method of compounding the phosphorus compound in the polyester of the present invention is not particularly limited. For example, (1) a compounding method in which a phosphorus compound is added at an optional stage in a polyester production reaction step; (3) a compounding method in which a phosphorus compound is added in a polyester production reaction step, a phosphorus element-containing polyester is produced, and a compounding method in which the polyester containing no phosphorus element is melt-kneaded,
A compounding method of melting and kneading the phosphorus compound can be used. Among them, a compounding method in which a phosphorus compound is added at any stage of the polyester production reaction step is preferable, and it is particularly preferable that the phosphorus compound is added after the esterification or transesterification reaction is substantially completed and before the polycondensation reaction starts. .

The method for producing the polyester composition of the present invention will be described with reference to the example of polyethylene terephthalate.

The high molecular weight polyethylene terephthalate used for fibers, films and the like is usually produced by any of the following processes. That is, a process of obtaining low molecular weight polyethylene terephthalate (bis-β-hydroxyethyl terephthalate) by a direct esterification reaction using terephthalic acid and ethylene glycol as raw materials, and further obtaining a high molecular weight polymer by a subsequent polycondensation reaction; This is a process using terephthalate (DMT) and ethylene glycol as raw materials to obtain a low-molecular-weight compound by a transesterification reaction, and to obtain a high-molecular-weight polymer by a subsequent polycondensation reaction. Here, the phosphorus compound is added at any stage of the polyester production reaction process,
The polyethylene terephthalate-based polyester is obtained by adding the compound after the esterification or transesterification reaction is substantially completed and before the start of the polycondensation reaction, and further performing the polycondensation reaction at a high temperature under reduced pressure.

[0018]

The present invention will be described in more detail with reference to the following examples. The physical properties in the examples were measured by the methods described below.

(1) Intrinsic viscosity [η] of polymer Measured at 25 ° C. using orthochlorophenol as a solvent.

(2) Phosphorus atom content in polymer Determined by X-ray fluorescence.

(3) Color tone of polymer Using a color difference meter (SM color computer model SM-3) manufactured by Suga Test Instruments Co., Ltd., Hunter values (L, a, b)
Value).

(4) Diethylene glycol (DEG) content of the polymer The polymer was alkali-decomposed and quantified by gas chromatography.

(5) Carboxyl end group content of the polymer The method of Maurice et al. [Anal. Chim. Act
a, 22, p363 (1960)].

(6) Presence or absence of insoluble foreign matter (transparency) After the completion of the polymerization operation, the presence or absence of insoluble foreign matter was determined by observing the molten polymer in the glass polymerization tube. The following three stages were used for evaluation.

：: No insoluble foreign matter was observed. Δ: Slightly recognized, but acceptable. X: Insoluble foreign matter is observed.

Example 1 Bis-β-hydroxyethyl terephthalate low polymer obtained by subjecting 100 parts of terephthalic acid and 50 parts of ethylene glycol to an esterification reaction according to a conventional method was added to 0.032 parts of antimony trioxide and cobalt acetate. 0.0
One part and 2,5-DCPPA were added. The content of the phosphorus compound in the polymer finally obtained was such that the phosphorus atom weight became 150 ppm. Thereafter, while the low polymer was stirred at 30 rpm, the temperature of the reaction system was gradually raised from 250 ° C. to 285 ° C., and the pressure was increased to 50 Pa
To perform a polycondensation reaction. When the predetermined stirring torque was reached, the reaction system was returned to normal pressure with nitrogen to stop the polycondensation reaction, and the mixture was discharged into cold water in a strand form and immediately cut to obtain polyester pellets.

The intrinsic viscosity of the obtained polymer is 0.67,
Diethylene glycol (DEG) content 0.9% by weight,
The carboxyl end group content was 12.6 equivalents / ton-polymer, and the color tone was L = 60 and b = -2.5. The transparency was good, and no insoluble foreign matter was observed.
In addition, it analyzed by fluorescent X-ray and confirmed that the phosphorus atom weight was 150 ppm.

After drying the pellets, the pellets were supplied to an extruder type spinning machine and melt-spun at a spinning temperature of 295 ° C. At this time, a metal nonwoven fabric having an absolute filtration accuracy of 15 μm was used as a filter, and a round hole of 0.6 mmφ was used as a base. 30cm length, 25cm inside diameter
After cooling slowly with a heating cylinder of φ, temperature of 300 ° C, cool and solidify by applying chimney cooling air, refuel, and take off speed 850m
/ Min. After stretching this unstretched yarn at a stretching temperature of 95 ° C while appropriately changing the stretching ratio so that the elongation of the stretched yarn is 14 to 15%, it is heat-treated at a heat treatment temperature of 220 ° C and a relaxation rate of 2.0%, A drawn yarn was obtained.

As described above, there was no problem with the polymer properties, and almost no increase in the filtration pressure during spinning was observed in the melt spinning step, and there was no yarn breakage during spinning and drawing, and the polymer had good moldability.

Examples 2 to 6, Comparative Examples 1 and 2 Polymers were polymerized and melt-spun in the same manner as in Example 1 except that the type of the phosphorus compound was changed. The results are shown in Table 1.

In the claims of the present invention, the polymer properties and the melt-spinning process changed favorably, but those without the phosphorus compound of the present invention showed a delay in the polycondensation reaction. The obtained polymer also had a large DEG content and a large amount of carboxyl terminal groups, was inferior in heat stability, and had a yellowish color tone. In addition, transparency is poor, insoluble foreign matter is recognized, or the filtration pressure rise becomes remarkable in the melt spinning process,
Many yarn breaks occurred and molding workability was poor.

[0032]

[Table 1] Examples 7 to 14 Polymers were polymerized and melt-spun in the same manner as in Example 1 except that the amount of the phosphorus compound (2,5-DCPPA) was changed. The results are shown in Table 2.

When the phosphorus content is low, yarn breakage tends to occur during stretching. When the phosphorus content is high, some insoluble foreign matter is found in the polymer, the filtration pressure increases during spinning, and the yarn breaks during stretching. Tended to occur.

[0034]

[Table 2]

[0035]

EFFECT OF THE INVENTION The polyester composition of the present invention has good heat stability, transparency and polymer color tone and is excellent in moldability, so that problems such as increased filtration pressure and thread breakage can be solved. It is suitably used for applications such as molded products such as films and bottles.

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Claims (6)

[Claims] 1. A polyester composition comprising a phosphorus compound represented by the following formula (1) and / or (2). Embedded image 2. The polyester composition according to claim 1, wherein the content of the phosphorus compound is 20 to 1000 ppm relative to the polymer in terms of phosphorus atom. 3. The polyester composition according to claim 1, wherein the polyester is a polymer mainly composed of polyethylene terephthalate. 4. The polyester composition according to claim 1, which is used for fiber applications. 5. A method for producing a polyester composition starting from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol, or a low molecular weight polyester oligomer, comprising the steps of: Or a method for producing a polyester composition, comprising adding the phosphorus compound represented by (2). Embedded image 6. The method for producing a polyester composition according to claim 5, wherein the phosphorus compound is added so that the content of the phosphorus compound is 20 to 1000 ppm relative to the polymer in terms of phosphorus atom.