JPH0238421A - Production of modified polyester - Google Patents

Abstract

PURPOSE:To produce a modified polyester excellent in color tone an oxidative destruction resistance by adding a heated mixture of polyethylene glycol with a hindered phenol compound to the system before the completion of the polycondensation for the polyester. CONSTITUTION:In the production of a copolyester having 3-10wt.% copolymerized polyethylene glycol of an MW of 600-4000, 1-10 pts.wt. hindered phenol compound, e.g., pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4- hydroxyphenyl)-propionate], is added to 100 pts.wt. polyethylene glycol, and the obtained mixture is heated at 50-200 deg.C for at least one hr and is added to system at an arbitrary time before the completion of the polycondensation for the polyester.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention relates to a method for producing a modified polyester that has excellent oxidative decomposition resistance. This invention relates to a method for producing a modified polyester, which is a modified polyester copolymerized with polyethylene glycol, and a molded article made from the modified polyester can be easily dyed.

[Prior Art] Polyester fibers, particularly polyester fibers containing polyethylene terephthalate as a main component, have excellent strength, dimensional stability, and texture, and are therefore used not only for clothing but also in industrial fields. However, polyester is difficult to dye because it is hydrophobic, does not have reactive functional groups in its molecules, has a highly crystalline and dense molecular structure, and has a high glass transition temperature. Ta. Particularly recently, there has been a desire for clothing that utilizes the advantages of blending or blending polyester fibers and natural fibers.

Dyeing of blended yarns or blended yarns of natural fibers and polyester fibers, such as dyeing of silk and polyester or wool and polyester, involves dyeing polyester fibers with disperse dyes and silk and wool with acid dyes in one or two baths. Polyester fibers are dyed using a bath method, but polyester fibers need to be dyed under high pressure, that is, at a dye bath temperature of 120 to 130°C. As a result, the strength of the blended fibers or blended silks and wools decreases, and the texture of the blends hardens, resulting in a significant loss of the characteristics of the silks and wools. In addition, there is a method of dyeing polyester fibers by adding a carrier to the polyester fibers for the purpose of lowering the dyeing bath temperature, but even this method has many problems such as contamination of the natural fibers with the carrier and toxicity of the carrier.

Therefore, various methods have been proposed to improve the dyeability of these polyester fibers. Among these, a method of copolymerizing polyoxyalkylene glycol with polyester is known to be particularly effective. However, when polyoxyalkylene glycol is copolymerized with polyester, the ether bonds become susceptible to attack by oxygen in the air, resulting in a decrease in the oxidative decomposition resistance of polynisdel, and the polymerization during the polycondensation reaction of polyester and after the completion of the polycondensation reaction. There was a problem that the polymer yellowed during the discharging and cooling process.

In addition, when spinning polyoxyalkylene glycol copolyester, there is a problem of yellowing when the polymer dries, and during spinning, there is a problem of yarn breakage due to abnormal retention in the spinning machine.

In addition, there have been many problems caused by a decrease in oxidation and decomposition resistance, such as yellowing of the fabric during a higher processing step after fiberization, especially a heat treatment step, and a decrease in the strength of the fiber. In order to improve the heat resistance, especially the oxidative decomposition resistance, of these polyoxyalkylene glycol copolymerized polyesters,
Japanese Patent No. 25646 proposes a method of adding and copolymerizing polyoxyalkylene glycol, which has good heat resistance, to polyester. However, the coloring of polyester copolymerized with polyoxyalkylene glycol during polycondensation is caused by poor heat resistance of ether bonds, and the improvement effect was small. On the other hand, special public Sho 44323
Publication No. 11, Special Publication No. 12591, Special Publication No. 44-12591, Special Publication No. 12591, Special Publication No. 4
Publication No. 4-13271, Japanese Patent Publication No. 45-7870,
Special Publication No. 45-24023, Special Publication No. 47-6426
@Bulletin and Special Publication No. 58-5938, etc.,
In order to improve the oxidative decomposition resistance of polyoxyalkylene glycol copolyester, an easily dyeable copolyester composition containing a sterically hindered phenol compound has been proposed. Although this method can prevent coloration during polycondensation, it is not only inferior in terms of improvement effect, but also has a significant reduction in the strength of the fiber due to the heat treatment in the higher processing stage, making it completely unsuitable for practical use.

[Problems to be Solved by the Invention] The present invention overcomes the problems of the prior art and provides a method for producing a modified polyester copolymerized with polyethylene glycol, which has excellent oxidative decomposition resistance and color tone. be.

[Means for Solving the Problems] The object of the present invention described above is to
When polycondensing a copolymerized polyester obtained by copolymerizing the following polyethylene glycol in an amount of 3% by weight or more and 10% by weight or less, 1 part by weight or more and 10 parts by weight or less of a hindered phenol compound is mixed with 100 parts by weight of polyethylene glycol. This can be achieved by a method for producing a modified polyester, which is characterized in that the mixture is heat-treated at 50° C. to 200° C. for 1 hour or more, and then the mixture is added at any stage until the completion of the polycondensation reaction of the polyester.

In the present invention, the molecular weight of polyethylene glycol is 60
It needs to be 0 or more and 4000 or less. If the molecular weight is less than 600, a part of the polyethylene glycol added during polymerization of the polyester will scatter under the reaction conditions of high temperature and high vacuum, so the amount of polyethylene glycol copolymerized into the polyester will not be constant. This may cause variations in physical properties such as strength and elongation, shrinkage rate, etc. of the obtained polyester yarn, and uneven dyeing may occur during dyeing.
This results in defects in the final product. In addition, in order to copolymerize polyethylene glycol with a low molecular weight of less than 600 to improve dyeability, it is necessary to increase the number of moles of copolymerization considerably compared to polyethylene glycol with a high molecular weight. There is a problem in that the softening point of polyester is lowered and the quality of the final product is lowered.

On the other hand, when polyethylene glycol with a molecular weight exceeding 4000 is used, the amount of high molecular weight substances that are not copolymerized increases in the polyester, which not only reduces the dyeability but also reduces the amount of dye to 1 when the fabric is heat-treated after dyeing. lead-out, light fastness, especially fading fastness, etc.
Causes a decrease in various color fastnesses.

The blending amount of polyethylene glycol needs to be 3% by weight or more and 10% by weight or less. If it is less than 3% by weight, the dyeability is insufficient, and if it exceeds 10% by weight, not only the dyeability will be saturated but also the effect of suppressing the oxidative decomposition of the hindered phenol compound will be insufficient. This is not preferable because the heat treatment effect with the dophenol compound becomes difficult to produce and the polymer becomes seedlings. In the present invention, the hindered phenol compound is a phenol derivative having a sterically hindered substituent at a position adjacent to a phenolic hydroxyl group, and is a compound having one or more ester bonds in the molecule. Specifically, pentaerythrityl-tetra extract [3(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], triethyl glycol-bis[3(3-tert-butyl-5-
Methyl-4-hydroxyphenyl)propionate, 1
,6-hexanethiolubis[3-(3,5-di-t
ert-butyl-4-hydroxyphenyl)propionate, 2,2-thio-diethylene-bis[3(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl-3-(3,5-di-tert-butyl-4-hydroxy) An example is phenyl)propionate. Among them, pentaerythrityl-tetrakis [3-
(3°5-di-tert-butyl-4-hydroxyphenyl)propionate] is preferred.

The effect of the present invention is that the polyethylene glycol and hindered phenol compound are heat-treated at a temperature of 50°C to 200°C and the treated material can be used at any stage from the polyester raw material preparation stage to the completion of the polycondensation reaction. This can only be achieved by adding it. The amount of hindered phenol compound added to polyethylene glycol is 1 part by weight per 100 parts by weight of polyethylene glycol.
The amount is not less than 10 parts by weight and not more than 10 parts by weight. The amount is preferably 2 parts by weight or more and 7 parts by weight or less. If it is less than 1 part by weight, the yellowing prevention effect of the modified polyester is small, and if it exceeds 10 parts by weight, the effect not only becomes saturated, but also causes staining of the spinneret nozzle during spinning, resulting in yarn breakage. The heat treatment requires 1 hour or more at a temperature of 50° C. or higher and 200° C. or lower. More preferably, the temperature is 60°C or higher and 150°C or lower for 6 hours or longer.

If it is less than 50°C, the yellowing prevention effect of the modified polyester is small, and if it exceeds 200°C, although the yellowing prevention effect of the modified polyester is recognized, the oxidative decomposition of the resulting modified polyester itself is undesirable.

Note that if the heat treatment time is less than 1 hour, the effect of preventing yellowing of the modified polyester is small. As mentioned above, by heating polyethylene glycol and hindered phenol compounds at a specific temperature range for 1 hour or more, it is possible to specifically prevent the modified polyester from becoming seedlings. Oxidative decomposition properties are improved. Although the reason is not clear, heat treatment causes a transesterification reaction between polyethylene glycol and a portion of the hindered phenol compound, and as a result, the reactant acts like a surfactant.
This is thought to be because the compatibility between polyethylene glycol and the hindered phenol compound becomes good, and the amount of the hindered phenol compound remaining in the modified polyester after polymerization is substantially increased.

In the conventional method of simply adding a hindered phenol compound to a reaction system, the compound has poor compatibility with the reaction system. It is thought that the added hindered phenol compound was scattered outside the reaction system, and its effect could not be fully exhibited.

The reason why the oxidative decomposition property of the polymer obtained by adding and copolymerizing the compound heat-treated at over 200° C. is reduced is considered to be as follows. That is, the ether bonds of polyethylene glycol copolymerized with polyester are severed by oxygen radicals excited by heat, and the molecular weight of the polyester is substantially reduced and deteriorated. At this time, if a hindered phenol compound is blended into the polyester, it is thought that it will be caught by the excited oxygen radicals, protect the ether bond, and at the same time deactivate itself. In other words, while the hindered phenol compound is alive, the polyoxyalkylene glycol copolyester is prevented from deteriorating, and when the hindered phenol compound is deactivated and loses its effect, the ether bonds are attacked by oxygen radicals. deterioration progresses. In other words, there is an induction period in the oxidative decomposition of modified polyester containing a hindered phenol compound before it begins to deteriorate, and the length of this induction period depends on the amount of oxygen radicals that are incorporated into the polymer and its ability to catch oxygen radicals. This is thought to be determined by the amount of hindered phenol compound with Therefore, it is thought that heat treatment at high temperatures deactivates the hindered phenol compound during treatment and reduces the oxidative decomposition properties of the resulting polymer.

The modified polyester in the present invention means a polyester obtained by copolymerizing the above-mentioned polyethylene glycol with a normal saturated linear polyester, and is not particularly limited to the saturated linear polyester. Preferred are polyethylene terephthalate and polybutylene terephthalate whose main glycol component is ethylene glycol or tetramethylene glycol as the acid component and as the glycol component.

Note that part of the dicarboxylic acid component of the polyester may be replaced by a small amount of dicarboxylic acid such as adipic acid, dodecanniic acid, and 5-sulfonodium isophthalic acid, or its ester, or oxybenzoic acid such as p-oxybenzoic acid and p-β-oxyethoxybenzoic acid. A carboxylic acid or ester may be substituted, and the glycol component may be replaced with a small amount of glycol other than the main glycol component, such as bisglycol ether of 1,4 bis(β-oxyethoxy)benzene bisphenol A. . However, in this case, it is preferably less than 2 mol%.

In addition, pentaerythritol, trimethylolpropane,
A small proportion of a chain branching agent such as trimellitic acid or trimesic acid may be used.

In addition, the modified polyester of the present invention contains pigments such as titanium oxide and carbon black, as well as conventionally known coloring inhibitors,
Of course, a light stabilizer, an antistatic agent, etc. may also be added.

When carrying out the polycondensation reaction of the present invention, foaming often becomes a problem, so for the purpose of defoaming, an organic silicone compound of 0.01% by weight or more and 1.0% by weight or less is added to the modified polyester. It is preferable. As the organic silicone, various silicone compounds can be used, but those that do not easily volatilize at the temperature of polymerization and spinning of the modified polyester are preferred. In particular, those having a weight loss rate of 1% or less when heat treated at 150° C. for 24 hours are preferred. As specific examples, dimethylpolysiloxane, diphenylpolysiloxane, methylphenylpolysiloxane, etc. can be used alone or in combination.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these Examples.

Note that the measurements in the examples were carried out by the following method.

(Intrinsic viscosity) Dissolve the dried sample in orthochlorophenol solvent,
This is a value measured at 25°C using an Ostwald viscometer.

(Polymer color tone value) Cylindrical chips of 3 diameters and 5 lengths were measured using a reflection method using a color computer (manufactured by Suga Test Instruments Co., Ltd., 8M color computer, model 5M-3).

(Oxidative decomposition of polymer) Polymer chips were mixed with dry ice and crushed, and 6 g of powder of 50 to 100 mesh was heated at 60°C for 6 hours for 1 hour.
After vacuum drying at #HΩ or less, the sample was placed in a chalet with a diameter of 60 m and treated with hot air (air) at 180° C. for 30 minutes, and the difference in intrinsic viscosity before and after the treatment was compared.

(Spinning property) When drawing 50 kg of undrawn thread, the number of thread breakages is as follows:
Evaluated by rank.

Example 1 A mixture of 100 parts by weight of dimethyl terephthalate, 80 parts by weight of ethylene glycol, dimethylpolysiloxane (Toshiba Silicone Corporation silicone oil>0.05 part, 0.04 part by weight of cobalt acetate, and 0.04 part by weight of antimony trioxide) was heated to 130°C to 230°C, methanol was distilled off, and the transesterification reaction was carried out, and the average molecular weight was 10.
00 polyethylene glycol 100, Irganox-1010 (pentaerythrityl tetra extract 3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), which is a Findart phenol compound manufactured by Ciba Geigy Co., Ltd.) 4 Blend parts by weight, 1
8 parts by weight (7.5% by weight based on the polymer) of the mixture heat-treated at 00°C for 24 hours were added, and further heated at 230°C for 3 hours.
Let it react for 0 minutes. Then trimethyl phosphate 0
．． After 5 minutes, 0.05 parts by weight of titanium dioxide was added as a 20% by weight ethylene glycol slurry to obtain a low polymer. The obtained low polymer was gradually raised in temperature from 230°C to 280°C, from atmospheric pressure to a high vacuum of 1 mmHQ or less, and then depressurized, and then polycondensed to produce a modified polyethylene with an intrinsic viscosity of 0.703 and a softening point of 257°C. Obtained terephthalate.

This modified polyethylene terephthalate has a boria color tone value of 2.0 and an intrinsic viscosity of 0.69 after an oxidative decomposition test.
It was 8. The intrinsic viscosity lowering salt was 0.005, indicating that the polymer had excellent oxidative decomposition properties.

The above modified polyester was dried using a rotary vacuum dryer.
Dry at 50°C for 6 hours at a vacuum level of 1 shoe HCI or less, perform spinning at a spinning temperature of 290°C and a spinning speed of 1350 m/m, and after winding, the resulting undrawn yarn has a residual elongation of 30 to 4.
Hot roll stretching was carried out under stretching conditions such that the stretching was 0%, and a drawn yarn of 75 denier and 24 filaments was obtained. The strength of the drawn yarn was 4.97 q/d, and the elongation was 37.8%.

Also, the undrawn yarn is 50%! The number of thread breakages during stretching was 0, which was no problem at all.

When the oil agent was removed from this drawn yarn and it was treated with hot air (air) at 180°C for 130 minutes under a constant length, the strength of the raw yarn was 4.
It was 70 CI/d (strength retention rate 95%), which was at a level that did not pose any practical problems.

Examples 2 to 10, Comparative Examples 1 to 7 The transesterification reaction and polycondensation reaction were carried out in the same manner as in Example 1, except that the heat treatment of polyethylene glycol and Findart phenol compound was carried out under the conditions shown in Table 1, and the addition was made. Modified polyethylene terephthalate having the physical properties shown in Table 2 and the results of spinning properties were obtained.

It can be seen that if the treatment temperature of the surface polyethylene glycol and the findart phenol compound is not appropriate, or if the treatment time is short, not only will the modified polyester turn into seedlings, but its oxidative decomposition properties will also deteriorate. On the other hand, if the blended amount of the Findart phenol compound is too large, the color tone and oxidative decomposition properties are both good, but the spinning property becomes poor, which is not preferable.

Regarding oxidative decomposition, the intrinsic viscosity before and after treatment is 0.0.
If it is 5 or more, it is not preferable because it causes problems such as seedling formation and deterioration of fiber physical properties at the higher processing stage and product stage.

Examples 11 and 12, Comparative Examples 8 and 9 The same procedures as in Example 1 were carried out, except that the amount of the heat-treated mixture of polyethylene glycol and Findart phenol compound was changed to the following conditions, and the results shown in Table 3 were obtained. .

Example 11: 4 parts (3.8% by weight)! l 12: 10 parts (9.1% by weight) Comparative Example 8: 2 parts (2.0% by weight) Table Comparative Example 9: 15 parts (13.0% by weight) Table The fibers of Comparative Example 8 are dyed Comparative Example 9 where the properties were insufficient and the amount of copolymerized polyethylene glycol was increased.
The yarn-spinning property was poor.

[Effects of the Invention] As described above, the present invention is a method for producing a modified polyester that has excellent color tone and oxidative decomposition properties, and the obtained modified polyester does not cause any problems during spinning, and does not require high processing steps. It is a modified polyester that shows little deterioration in fiber properties even when subjected to various heat treatments.

The fibers obtained using the modified polymer of the present invention can be used 100% as is as woven fabrics, knitted fabrics, non-woven fabrics, etc., but they can also be used in particular by blending or spinning with natural fibers, silk, wool, cotton, etc. It is extremely practical and suitable for the field of application.

Claims (1)

[Claims] When polycondensing a copolymerized polyester obtained by copolymerizing polyethylene glycol with a molecular weight of 600 or more and 4000 or more and 3% or more and 10% or less, 1 part by weight or more of a hindered phenol compound and 10 parts by weight or more per 100 parts by weight of polyethylene glycol. A method for producing a modified polyester, which comprises mixing parts by weight or less, heating the mixture at 50°C to 200°C for 1 hour or more, and then adding the mixture at any stage until the polycondensation reaction of the polyester is completed.