JPH0912666A - Polyurethane and polyester diol used therefor - Google Patents

Abstract

PURPOSE: To obtain a polyurethane which is free from problems, such as white smoke, odor, thread breakage, sticking between fibers, and degradation in life of a spinning nozzle, arising during spinning. CONSTITUTION: This polyurethane is obtd. by reacting a polyester diol, an org. diisocyanate, and a chain extender. subject to the condition that the polyester diol contains 100ppm or lower cyclic ester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane and a polyester diol as one raw material thereof for obtaining a polyurethane fiber which has less fluff and yarn breakage after spinning and which does not shorten the life of a spinning nozzle.

[0002]

2. Description of the Related Art Conventionally, polyurethane has been attracting attention as a substitute material for rubber and plastic because of its high elastic recovery property and excellent abrasion resistance and oil resistance, and it has also been widely used as a fiber. Polyurethane is generally produced by mixing a polymer diole, an organic diisocyanate, and optionally a chain extender such as 1,4-butanediol and hexamethylenediamine, and polymerizing the mixture. The molecular diol constitutes a soft segment, the chain extender constitutes a hard segment, and the hard segment and the soft segment aggregate between molecules to cause phase separation, resulting in excellent elongation and elastic recovery. Is obtained. Polyester-based, polyether-based, and polycarbonate-based polyurethanes are known as polyurethanes, and as the fibers, polyether-based polyurethanes are widely used.
However, attempts have been made to fiberize a polyester-based polyurethane having excellent mechanical properties such as heat resistance, and in order to improve the water resistance and abrasion resistance, which are the drawbacks of the polyester-based polyurethane, A polyurethane prepared by polymerizing a polyester polymer diole consisting of methyl-1,8-octanediol, 1,9-nonanediol and dicarboxylic acid and diisocyanate in the presence or absence of a chain extender is proposed. (JP-A-62-22817 and JP-A-2-20514).

[0003]

The polyester used as the soft segment of such polyester-based polyurethane contains by-products due to an equilibrium reaction during the polymerization. The low molecular diol, which is one of the by-products, is incorporated into the hard segment of the polyurethane, so that the cohesiveness of the hard segment is reduced and the mechanical properties such as heat resistance, which is an advantage of the polyester polyurethane, are improved. This caused a decrease in the performance. In order to solve such a problem, the present inventors have proposed a polyurethane using a high molecular diol in which the content of the low molecular diol is specified. However, it was not possible to suppress white smoke and odor generated during spinning, fiber breakage, sticking between fibers, and shortening of the life of the spinning nozzle by only removing low molecular weight diol to a specific amount. As a result of further studies in view of such problems,
In order to solve the problems such as white smoke and odor generated during spinning, yarn breakage, sticking between fibers, and shortening of the life of the spinning nozzle, the amount of cyclic ester as well as low molecular weight diol as a by-product is adjusted. I found that I needed to control.

[0004]

The present invention is a polyurethane obtained by the reaction of a polyester diol, an organic diisocyanate and a chain extender, wherein the amount of cyclic ester contained in the polyester diol is 100 ppm
The present invention relates to a polyurethane characterized by being the following polyester diol and a polyester diol as one raw material thereof.

The amount of cyclic ester contained in the polyester diol used in the present invention must be 100 ppm or less, particularly 50 ppm or less. Since the cyclic ester is blocked at the terminal functional group, it is not incorporated into the hard segment of the polyurethane during the synthesis of the polyurethane, but it exists as a single impurity together with the polyurethane in the system of the polymerization apparatus. Therefore, in any case, such as when the polyurethane is once pelletized and melt-spun, or when melt-spun directly through the spinneret in a molten state, this impurity is discharged from the spinning nozzle together with polyurethane, and most of it is It is recognized as white smoke with an odor. However, a part of them adheres to the spinning nozzle portion, causing frequent occurrence of yarn breakage and shortening of the spinning nozzle life. Therefore, it is necessary to specify the cyclic ester content contained in the polyester diol.
The content of the cyclic ester in the polyester diol is
It can be calculated from the peak area ratio of high performance liquid chromatography.

As a method for removing the cyclic ester from the polyester diol, usual vacuum distillation and thin film (molecule) are used.
Distillation and the like can be mentioned, but thin film distillation is preferable in that the cyclic ester can be removed in a short time. Distillation is
In the thin film distillation method, 100 to 180 ° C., especially 150 to 17
What is performed in the range of 0 ° C. is 100 to 100 in the vacuum distillation method.
It is preferably carried out at 140 ° C, particularly in the range of 100 to 120 ° C. The degree of vacuum in the vacuum distillation method is 0.01 to
It is preferably in the range of 1 mmHg, particularly 0.01 to 0.5 mmHg. Further, the treatment time is preferably in the range of 1 to 15 minutes, particularly 1 to 5 minutes in the thin film distillation method, and 2 to 8 hours, particularly 4 to 6 hours in the vacuum distillation method. The content of cyclic ester is 100 ppm by selecting distillation type, temperature, vacuum degree and time from the above range.
It can be:

The polyester diol in the present invention is preferably one having a number average molecular weight of 1,000 to 3,000 obtained by the reaction of the diol component and the dicarboxylic acid component. From the viewpoint of heat resistance and hot water resistance of the obtained polyurethane, 1500 or more is preferable, and from the viewpoint of elongation and elastic recovery of the fiber made of the polyurethane, it is preferably 3000 or less. The number average molecular weight of the polyester diols referred to in the present specification are all JIS K 157.
7 is a number average molecular weight calculated on the basis of the hydroxyl value measured according to 7.

Geo-in the polyester diol
Examples of the component include ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and 3-methyl- 1,5-pentanediol, 1,
A general-purpose diol such as 8-octane diol can be used, but the diol is not particularly limited, and even when used alone, it is 2
More than one species may be used in combination. Further, as the dicarboxylic acid component, succinic acid, glutaric acid, adipic acid, sebacic acid,
Aliphatic dicarboxylic acids such as dodecanedioic acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and their ester-forming derivatives can be mentioned, and these dicarboxylic acid units can be used alone or 2 You may use together 1 or more types. In the present invention, a polyester diol composed of azelaic acid and 3-methyl-1,5-pentanediol is preferable in terms of hydrolysis resistance and elastic recovery in a low temperature atmosphere.

The method for producing the polyester diol is not particularly limited, and the polyester diol is produced by polycondensing the above-mentioned diol component and dicarboxylic acid component by a conventionally known transesterification reaction, direct esterification reaction or the like. be able to. In that case, it is preferable to carry out the polycondensation reaction for producing the polyester diol in the presence of a titanium-based polycondensation catalyst. In such a case, titanium contained in the polyester diol at the end of the polycondensation reaction. It is preferable to deactivate the polycondensation catalyst. When the deactivation treatment of the titanium-based polycondensation catalyst is not carried out, mechanical properties such as heat resistance of the obtained polyurethane are likely to be lowered.

When a polyester diol polycondensed in the presence of a titanium-based polycondensation catalyst is used, the titanium-based polycondensation catalyst has been conventionally used in producing a polyester-based polymer. Any of the titanium-based catalysts mentioned can be used. Examples of preferable titanium-based catalysts include titanic acid, tetraalkoxytitanium compounds, titanium acylate compounds, and titanium chelate compounds. More specifically, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-2-
Ethylhexyl titanate, tetrastearyl titanate
, Polyhydroxytitanium stearate, polyisopropoxytitanium stearate, titanium acetylacetonate
And triethanolamine titanate. In that case, the amount of the titanium-based polycondensation catalyst used is not particularly limited, but is generally about 0.1 to 50 ppm, especially 1 to 1 with respect to the total amount of the diol component and the dicarboxylic acid component for forming the polyester diol. ~ 30pp
m is preferable.

As a method for deactivating the titanium-based polycondensation catalyst contained in the polyester diol, for example, the polyester diol obtained by the polycondensation reaction is heated and brought into contact with water or steam to deactivate it. And a method of treating the polyester diol with a phosphoric acid, a phosphoric acid ester, a phosphorous acid, a phosphorous compound such as a phosphorous acid ester, and the like. Among them, a method of contacting with water or steam under heating. Is preferred. In the case of this method, 1% by weight or more of water is added to the polyester diol obtained by the polycondensation reaction, and the mixture is heated at a temperature of 70 to 150 ° C. for 1 to 3 hours. The heating may be carried out under normal pressure or may be carried out under pressure. If the system is depressurized after deactivating the titanium polycondensation catalyst, the water used for deactivation can be removed, which is desirable. .

As the organic diisocyanate in the present invention, any of the organic diisocyanates conventionally used in the production of polyurethane can be used, and the kind thereof is not particularly limited, and it may be an aromatic diisocyanate or an alicyclic group. One or more of diisocyanate and aliphatic diisocyanate can be used. 4,4 'of which
-Diphenylmethane diisocyanate, p-phenylene diisocyanate, toluylene diisocyanate, 1,
Aromatic diisocyanates such as 5-naphthylene diisocyanate are preferred.

In the present invention, a chain extender can be used if necessary. As the chain extender, a compound containing two or more hydrogen atoms capable of reacting with isocyanate is used. Specifically, ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol and the like are used. These may be used alone or in combination of two or more. The amount of the chain extender used is preferably 0.25 to 5 mol times with respect to the organic diisocyanate.

The reaction method for obtaining the polyurethane of the present invention is not particularly limited, and the polyester di-
, An organic diisocyanate and a chain extender,
It may be produced by either a prepolymer method or a one-shot method using a known urethanization reaction technique. Among them, it is preferable to carry out the melt polymerization substantially in the absence of a solvent, and particularly preferable is the continuous melt polymerization using a multi-screw screw type extruder. The method may vary depending on the content of the polyester diol used, the type of organic diisocyanate, the content of the chain extender, etc., but when producing polyurethane using a multi-screw screw type extruder, In general, each component is continuously or almost simultaneously supplied to an extruder continuously and continuously melt-polymerized at 190 to 280 ° C., preferably 200 to 260 ° C. to produce polyurethane, and then extruded.
It is advisable to produce polyurethane in the form of pellets, chips, etc. by cutting. To obtain a fiber which may use a tin-based urethane-forming catalyst having catalytic activity for the urethane-forming reaction, such as tin octylate, monomethyltin mercaptoacetate, and monobutyl triacetate in the production of polyurethane. The molecular weight of the polyurethane is generally 5,000 to 500,000, especially 10,000 to 3,000.
00 is preferable.

If necessary, additives such as colorants and agents, ultraviolet absorbers, flame retardants and antioxidants may be added after or during the polymerization of polyurethane.

The polyurethane of the present invention can be made into an elastic fiber by a known spinning method such as a wet method, a dry method and a melt spinning method. It is preferable that the pellets are once pelletized and then melt-spun, or the melt-polymerized polyurethane is directly spun through a spinneret (polymerization direct-spinning) in a molten state. In the case of melt spinning, the spinning temperature is 200 to 2
The temperature is preferably 50 [deg.] C., particularly 200 to 230 [deg.] C., and the solid phase polymerization is preferably carried out by heat-treating at a temperature of 60 to 150 [deg.] C. for 1 to 48 hours after being wound around a cheese.

[0017]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In the following examples, the number average molecular weight of polyester diol, the content of cyclic ester, and the evaluation standard were measured or evaluated by the following methods.

[Number average molecular weight of polyester diol]
A predetermined amount of polyester diol was esterified with an excess of phthalic anhydride, and then the residual amount of phthalic acid was obtained by neutralization titration with a potassium hydroxide solution. From the hydroxyl value (mgKOH / g) of the polyester diol, It was determined by converting the number average molecular weight. [Cyclic Ester Content (ppm)] Using a cyclic ester solution of known concentration, the relationship between the peak area and the concentration of high performance liquid chromatography is obtained in advance, and the concentration is calculated from the cyclic ester peak area of the sample. I asked. The measurement conditions are as follows. Chromatography: Shimadzu High Performance Liquid Chromatograph LC-10AS Eluent: Isopropanol: n-Hexane = 25: 75 Column: Toso-TSKgel Silica-60 Sample solution: Ethyl acetate: Eluent = 1: 1 Flow rate: 1 ml / Min Column oven temperature: 35 ° C Detector: Showa Denko Shodex RI-71 Chart speed: 1 cm / min

[Fiber Morphology Immediately After Spinning] ◯: No sticking or breakage between single yarns. Δ: Slight sticking was observed between the single yarns, but there was no problem in practical use. X: Sticking between single yarns is observed, and the yarn cannot be used as a yarn.

The abbreviations for the compounds used in the following examples and the contents of the compounds are as shown in Table 1 below.

[0021]

[Table 1]

Examples 1 to 4 and Comparative Examples 1 to 3 << Production of polyester diol >> 3000 g of MPD and 3760 g of AZ (MPD / AZ = 1.7 / 1 molar ratio)
Was charged into a reactor, and nitrogen gas was passed under normal pressure,
The esterification reaction was carried out while distilling the water generated at 5 ° C. out of the system. When the acid value of the reaction product reached 30 or less, 90 mg of tetraisopropyl titanate was added,
The reaction was continued while reducing the pressure to 100 mmHg. Acid value is 1
When the temperature became the following, the degree of vacuum was gradually raised by a vacuum pump to complete the reaction. As a result, 5700 g of PMAZ having a hydroxyl value of 56 and an acid value of 0.1 and a number average molecular weight of 2000 (hereinafter, referred to as PMAZ-A) was obtained.

<Production of PMAZ in which titanium-based catalyst is deactivated> 1000 g of the above PMAZ-A is heated to 100 ° C., 20 g (2.0% by weight) of water is added thereto and heated for 2 hours with stirring. By doing so, the titanium-based catalyst was deactivated. By distilling off water under reduced pressure from the obtained mixture, PMAZ in which the titanium-based catalyst was deactivated (hereinafter referred to as PMAZ-B) was obtained. PMAZ- above
When B was analyzed by high performance liquid chromatography, it contained 500 ppm of cyclic ester. When this cyclic ester was analyzed by GC-MS, it was found that MP
It was a cyclic ester composed of D and AZ having different molecular weights.

<< Adjustment of the amount of cyclic ester in polyester diol >> Thin film distillation (molecular distillation) of PMAZ-B described above.
Were purified under the conditions of a treatment temperature of 160 ° C. and a treatment time of 3 to 15 minutes to obtain various PMAZ shown in Table 2 (Example 1
4 and Comparative Examples 1 to 3). In addition, the above PMAZ-B
Was purified by vacuum distillation under the conditions of a treatment temperature of 100 to 120 ° C., a treatment time of 4 to 6 hours and a degree of vacuum of 0.01 to 10 mmHg to obtain various PMAZs shown in Table 2 (Example 5 and Comparative Example 4). ).

<< Production and Spinning of Polyurethane >> PMAZ-B (heated to 30 ° C.) in which the amount of cyclic ester is adjusted,
MDI (heated to 50 ° C.) and BD (heated to 30 ° C.) were used in a molar ratio as shown in Table 2 and their total feed amount was 11
A twin-screw screw-type extruder (30φ, L / D = 3) that rotates coaxially from the metering pump so as to achieve 7 g / min.
7) and continuously melt-polymerized at 260 ° C. The melt-polymerized polyurethane was directly fed to the spinning machine in a molten state, and melt-spun under the conditions of a spinning temperature of 205 ° C., a cooling air dew point of 5 ° C. and a spinning speed of 500 m / min to obtain a 40 denier monofilament. The white smoke from the nozzle during spinning, the presence or absence of odor, and the morphology of the obtained filament were observed, and the replacement cycle of the spinning nozzle was measured. Table 2 shows the results.

[0026]

[Table 2]

When polyester diol containing a large amount of cyclic ester was used (Comparative Examples 1 to 4), white smoke was generated from the nozzle during spinning, and odor was also felt. In addition, the nozzle had to be replaced within one week, which was inferior in terms of cost performance. Further, the single yarn obtained by spinning had many breakages and sticking and was of no practical use. On the other hand, in the case of using the polyurethane of the present invention, white smoke and odor were not recognized during spinning, and the nozzle was replaced for 10 to 15 days, and the nozzle life was long and advantageous in terms of cost. In addition, no breakage or sticking was observed in the single yarn obtained by spinning.

[0028]

According to the present invention, polyurethane excellent in mechanical properties such as durability, heat resistance, and hot water resistance, especially white smoke and odor are not recognized during fiber formation, and the nozzle life is long.
Further, it is possible to provide a polyurethane capable of obtaining a fiber free from sticking and thread breakage.

Claims (3)

[Claims] 1. A polyurethane obtained by the reaction of a polyester diol, an organic diisocyanate and a chain extender, wherein the amount of cyclic ester contained in the polyester diol is 100 ppm or less. Polyurethane characterized by being. 2. A polyester dio having a cyclic ester content of 100 ppm or less, which has been treated by thin film distillation at a treatment temperature of 100 to 180 ° C. and a treatment time of 1 to 15 minutes.
Le. 3. A processing temperature of 100 to 140 ° C., 0.01 to
It was processed by vacuum distillation at a vacuum degree of 1 mmHg and a processing time of 2 to 8 hours, and the cyclic ester content was 100 ppm.
The following polyester diol.