JPH086207B2 - Water soluble polyester fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention can be produced by melt spinning and is easily prepared by hot water, hot water or even dilute alkaline water (hereinafter collectively referred to as hot water). The present invention relates to a water-soluble polyester fiber that can be dissolved and removed in a high-performance polyester fiber, which is used in the production of chemical lace base fabrics, patterning of knitted fabrics and woven fabrics, and separation of continuously knitted socks and sweaters. It is extremely useful for quality improvement and labor saving.

[Prior Art] As a fiber soluble in water, a fiber made of polyvinyl alcohol (hereinafter, abbreviated as PVA) is widely used. However, since this PVA fiber is generally produced by a dry spinning method, there is a problem that the productivity is low and the production cost is high as compared with the case of melt spinning.

Further, as another water-soluble polymer, a copolyester or a copolyamide which has been water-solubilized by copolymerization has been proposed.

For example, sodium 5-sulfoisophthalate 20-
JP-B-58-39926 proposes to make a polyester water-soluble by copolymerizing it in a large amount of 60% by weight and to use it as one component of a composite fiber. However, when a large amount of 5-sulfoisophthalic acid sodium salt is added as described in this publication, it is difficult to obtain a polymer having a sufficient degree of polymerization due to the foaming / thickening action during the condensation polymerization reaction, and the melting The spinnability during spinning is also not satisfactory. Moreover, since this water-soluble polyester is eluted even in cold water, water cannot be used for discharging the molten polymer after the polymerization reaction and cooling at the time of gut formation, and it is necessary to cool with a special device such as discharge air cooling. is there. In the case of this discharge air cooling, a belt or roll for feeding the polymer is required in a long cooling zone, but such a long cooling zone causes oxidative decomposition of the polymer. Furthermore, since it is deformed by moisture in the air when it is handled after it is made into fibers, it is difficult to handle it at the time of post-processing, and it has not yet been put to practical use.

Further, water-soluble polyesters have been proposed in many applications such as adhesives, sizing agents, paints, etc., which are used as an aqueous solution (for example, JP-B-47-40873, 57-26309, and 60-1334). However, none of these proposals considers use as an aqueous solution.

Furthermore, the water-soluble polyamide described in Japanese Examined Patent Publication No. 55-1374 has poor thermal stability at high temperatures, poor spinnability due to the oligomers and monomers contained therein, and has a long time for hot water dissolution. There are many problems such as the need for the product, and it has not been put to practical use.

As described above, various water-soluble polymers that can be melt-spun have been proposed, but in actual production, there are many problems in the spinnability and handleability during post-processing. In the present situation, a water-soluble fiber which can be replaced is not obtained.

[Problems to be Solved by the Invention] That is, the present invention does not have the above-mentioned drawbacks, can be easily made into fibers by melt spinning, and is easy to handle during post-processing and can be easily dissolved and removed by hot water or the like. The main object of the present invention is to provide a polyester fiber that has the properties of being insoluble in cold water, soluble in hot water, and the like.

That is, the present invention provides a water-soluble polyester fiber which can be produced with high productivity, is easy to process, and is suitable for industrial production.

[Means for Solving the Problems] In order to achieve this object, the present invention comprises terephthalic acid and ethylene glycol as main constituent components, and contains 8 to 16 mol% of 5-sodium sulfoisophthalic acid based on all acid components. Acid, 5 to 40 mol% of isophthalic acid, and 0 to 20 wt% based on the total amount of polyalkylene glycol (number average molecular weight 400 to 6000) or a copolyester containing a derivative thereof, which is a substantially single substance. It is a component fiber and comprises water-soluble polyester fibers having a fiber strength of at least 0.8 g / d.

As described above, the present invention provides a hot water obtained by copolymerizing polyethylene terephthalate with at least 5-sodium sulfoisophthalic acid and isophthalic acid, and optionally with a polyalkylene glycol having a specific molecular weight in a specific ratio. It is characterized by being a substantially single component fiber made from a soluble copolyester.

The copolymerization component 5-sodium sulfoisophthalic acid is
8 to 16 mol%, preferably 10 to 14 mol% based on all acid components
Is good. If it is less than 8 mol%, the removability by dissolution with hot water or the like is insufficient. On the other hand, if it exceeds 16 mol%, it will be eluted even in cold water, making it difficult to cool the produced polymer, to handle it during melt spinning or drawing, and to make it unsuitable for industrial production.

Further, it is necessary to copolymerize 5 to 40 mol% of isophthalic acid with respect to the total acid component together with the above-mentioned 5-sodium sulfoisophthalic acid. When isophthalic acid is less than 5 mol%, the solubility in hot water or the like decreases, and flaky insoluble matter remains when the hot water or the like dissolves. On the other hand, if this isophthalic acid exceeds 40 mol%, the softening point of the obtained polymer will be too low, and the drying before melt spinning cannot be performed sufficiently, so that melt spinning will be difficult, and moreover, it will be possible to perform melt spinning. However, it is difficult to obtain a fiber that is practically satisfactory, because the single yarn or the inter-filament fusion occurs in the spinning yarn during spinning or drawing.

This copolyester has terephthalic acid and ethylene glycol as main constituents (that is, about 50 mol% or more of all constituents). If the proportion of this terephthalic acid is too low, the softening point of the polymer becomes too low, which causes troubles in chip drying before melt spinning and in winding yarn during spinning and drawing.

This copolyester is copolymerized with a hydrophilic polyol and the like in addition to the above essential copolymerization components in a small amount which does not impair excellent properties such as insolubility in cold water and solubility in hot water or hot water. May be.

The hydrophilic polyol component to be copolymerized is preferably a polyalkylene glycol having a number average molecular weight of 400 to 6000 or a derivative thereof, and the copolymerization ratio thereof is 20 wt% or less, and further 3 to 15 wt% with respect to the total polymer. Preferably. In order to obtain a soluble effect in dilute alkaline water, it is desirable to copolymerize at least 3 wt%. On the other hand, if it exceeds 20% by weight, the stability of the fiber against cold water decreases.

Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Further, as the derivative, ethylene oxide is added to the phenolic hydroxyl group of bisphenol compound such as bisphenol A,
Examples thereof include polyether compounds obtained by ring-opening addition of propylene oxide and butylene oxide.

The number average molecular weight of this polyalkylene glycol is
It is preferably 400 to 6000, more preferably 600 to 4000. When the number average molecular weight is out of this range, the fiber-forming property of the obtained copolymer is insufficient, which makes the fiber production difficult.

[Operation] The fiber according to the present invention is a substantially single-component fiber composed of a copolyester having properties insoluble in cold water and soluble in hot water. The property of being insoluble in cold water and soluble in hot water or the like is very important for producing fibers by melt spinning. That is, when it is soluble in cold water as well, it is not possible to use the discharge cooling method into a water bath that is generally used when discharging molten polymer after the completion of the reaction of polycondensation, and the chips and fibers are in air. Since it is deformed by the water content, it is difficult to carry out stable industrial production.

Copolymerization of a specific amount of 5-sulfoisophthalic acid is indispensable for water solubilization of polyester, but it is soluble in hot water and hot water and insoluble in cold water to facilitate the production of chips and fibers and their handling. Therefore, it is necessary to copolymerize a specific amount of isophthalic acid.

Further, as the other copolymerization component, a specific amount of the above-mentioned polyalkylene glycol is copolymerized to make it soluble in dilute alkaline water without impairing the property of being soluble in hot water or hot water and insoluble in cold water. be able to. As the diluted alkaline water, a concentration of about 0.2 to 2 N is used, and examples thereof include an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, and an aqueous sodium carbonate solution. Note that dilute alkaline water having such a low concentration is advantageous for industrial use because it hardly needs to be diluted when treating wastewater.

The water-soluble fiber according to the present invention, which is obtained by copolymerizing isophthalic acid or further polyalkylene glycol with 5-sulfoisophthalic acid, is a transparent liquid by dissolving in hot water, warm water or further dilute alkaline water, or A liquid in an emulsified fine dispersion state can be obtained, and the liquid can be dissolved in hot water or the like without leaving any foreign matter residue without using any auxiliary agent.

Further, the fiber according to the present invention, 0.8g / d or more, preferably
Since it has a fiber strength of 1.0 g / d or more, it can be easily commercialized by the ordinary fiber product manufacturing process such as knitting and weaving, by using the fiber alone or by mixing with other fibers. .

The fiber according to the present invention can be easily produced by a spinning method or conditions by melt spinning in accordance with a usual polyethylene terephthalate fiber spinning method, if a spinning oil agent and heating conditions during spinning are appropriately selected as described below. You can For example, a melt-spinning method, a spinning method in which the material is once wound into a package and then drawn, a spinning method in which spinning and drawing are continuously performed, and a so-called high-speed spinning method in which spinning is performed at a high speed and winding is performed without mechanical stretching. The method may be used for spinning. The conditions such as the spinning temperature and the winding speed at the time of winding the undrawn yarn may be basically set in accordance with the usual polyethylene terephthalate fiber spinning conditions. However, in the case of the fiber according to the present invention, in order to obtain a fiber strength of 0.8 g / d or more, it is necessary to use a non-hydrated oil agent for lubrication during spinning, and to perform heating at 90 degrees or more in the spinning process. Is.

A non-hydrated oil agent is an oil agent that contains substantially no water. For example, an oil agent mainly composed of a leveling agent such as a compound obtained by adding ethylene oxide to oleyl alcohol, an antistatic agent, an emulsifier, etc., is added and diluted with mineral oil. Very small amounts of water are acceptable, but the amount should be at most 3% or less.

The degree of heating in the yarn making step may be about 90 ° C. or more and about 3 ° C. or less lower than the softening temperature of the polymer.

The obtained fiber can be used as a material that is temporarily mixed for the convenience of the weaving process when manufacturing a fiber product by, for example, weaving. For example, by mixing with the material fibers, a chemical lace base fabric, a knitted fabric with a weaving pattern, a woven fabric, and then treating the resulting knitted fabric with a means such as immersing in hot water or the like, By the method of dissolving and removing only the fibers from the fiber product according to the present invention, knitted and woven fabrics having a watermark can be efficiently manufactured. Also, socks, sweaters, etc. can be used at divided positions when they are continuously knitted, and the separation work can be performed by treatment with hot water or the like.

In the process of manufacturing these fiber products, the fiber according to the present invention also undergoes a twisting yarn and a carding process as in the case of a normal water-insoluble fiber, but since it has the property of being insoluble in cold water, a yarn breakage in these processing steps, Stable processing is possible without causing processing problems such as fluffing and entanglement.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples.

Parts in the examples mean parts by weight, and the solubility of the fiber in cold water, hot water or dilute alkaline water, strength and elongation, and softening point and heat resistance of the polymer were evaluated by the following methods.

Solubility in cold water After immersing 1 g of thread-like thread in 100 g of water at 30 ° C for 20 hours, it was taken out and dried in vacuum, and the weight change of the thread was examined.

Solubility in hot water: After immersing 1 g of thread-like thread in 100 g of hot water at 95 ° C for 20 minutes, taking out and vacuum drying, observing changes in the surface and cross section of the thread and examining by cross-sectional micrograph, Moreover, the change in weight was examined.

Solubility in dilute alkaline water: Sodium hydroxide 0.1wt% 3
After immersing 1 g of thread-like thread in 100 g of dilute alkaline water at 0 ° C for 20 minutes, take out and vacuum dry, observe the change of the surface and cross section of the thread and examine it by cross-sectional micrograph, and also check its weight change. Examined.

High elongation: Tensilon RTM-1 manufactured by Toyo Baldwin Co., Ltd.
00, using a sample fiber with a sample length of 20 cm, pulling speed 20
The measurement was conducted at 20 ° C. and 65% RH in cm / min.

Softening point: After heat-treating the polymer chip (70 ° C x 3hr),
It was measured with a penetrometer. Thickness at a heating rate of 10 ° C / min
The softening point was defined as the temperature at which a 3 mm chip deformed 0.1 mm.

Heat resistance: After the chips were vacuum dried at 10 ° C below the softening point for 8 hours, the viscosity at a melt storage time of 10 minutes and 30 minutes was measured at 285 ° C with a melt indexer.

-Example 1 99.7 parts of dimethyl terephthalate which is a methyl ester of terephthalic acid (TPA), 25.7 parts of dimethyl isophthalate which is a methyl ester of isophthalic acid (IPA), 93.3 parts of ethylene glycol and 0.135 parts of calcium acetate are charged into a reaction vessel. A transesterification reaction was carried out at 130 to 230 ° C. while distilling off by-product methanol. Then, 26.1 parts of dimethyl 5-sodium sulfoisophthalate, which is a methyl ester of 5-sodium sulfoisophthalic acid (SI), 0.03 part of antimony trioxide, 0.0075 part of phosphoric acid and lithium acetate.
After adding 3 parts and reacting at 230-250 ℃ for 1 hour, 250-27
Polycondensation was carried out at 5 ° C. under reduced pressure (1 mmHg or less) for 3 hours. After polymerization, discharge the polymer into a water bath at room temperature, cool,
Gutted and cut into chips. Of the obtained polymer
IV (intrinsic viscosity in orthochlorophenol solution) is 0.6
0, softening point is 130 ℃, melt viscosity at 285 ℃ melt storage time 10 minutes 3618 poise, melt storage time 30 minutes melt viscosity 33
It was 79 poise.

After vacuum drying the obtained chips at 90 ° C for 24 hours,
Melt-spinning was performed at 295 ° C. using a spinneret with 0.23 mm and 10 holes. The spun yarn was air-cooled, oiled with a non-hydrated oil, and then circulated 6 times around a first Nelson roller heated at 2000 m / min, 90 ° C, and then heated at 3500 m / min, 110 ° C. The second Nelson roller was orbited 5 times, stretched, and wound. The resulting yarn was about 30 denier, 10 filaments and had the properties shown in Table 1. As the non-hydrated oil agent, an oil agent composed of an ethylene oxide adduct of oleyl alcohol, an imidazoline antistatic agent and a mineral oil was used.

Although the yarn was spun directly at a high speed of 3500 m / min, the yarn breakage during spinning was not a problem and stable spinning was possible. In addition, as shown in Table 1,
It is insoluble in cold water and easily soluble in hot water, and the yarn strength is
1.47 g / d, which was a level that could withstand post-processing steps.

Then, knitting using the obtained water-soluble fibers at the divided positions when knitting the stockings continuously, and then,
When it was immersed in boiling water for 20 minutes and dried, it showed excellent splittability.

Examples 2-3 and Comparative Examples 1-5 Examples in which the copolymerization ratio of TPA, IPA, SI in the copolymerized polyester was changed, or polyethylene glycol (PEG) having a number average molecular weight of 1000 was further copolymerized, 1
In the same manner as above, copolymerized polyesters having various compositions shown in Table 1 were polymerized. The fiber was dried, melt-spun and drawn in the same manner as in Example 1 except that those copolymerized polyesters were used. The results are shown in Table 1.

From the results shown in Table 1, the water-soluble fiber obtained from the copolyester having the composition specified in the present invention has both hot water easy solubility and cold water insolubility, and moreover, has a yarn strength sufficient to withstand the post-processing step. Had. In contrast, Comparative Examples 1 to
Water soluble fibers from the copolyesters of 3 and 5 are:
The solubility in hot water was insufficient, and the solubility in cold water was also high. Therefore, neither fiber was easy to handle and easily soluble in hot water. Further, in Comparative Example 4, there was a large amount of polymer fusion at the polymer drying stage, and it was difficult to melt-spin itself.

[Effects of the Invention] The hot water-soluble polyester fiber according to the present invention has the property of being insoluble in cold water and soluble in hot water, etc., and thus is easy to handle during post-processing, and moreover, by treating with hot water or the like. It can be easily dissolved and removed from the textile.

Moreover, this fiber can be spun by the same melt spinning method as in the case of ordinary water-insoluble fiber, and can be manufactured with high productivity.

Furthermore, since the polymer used has sufficient heat resistance and spinnability, by optimizing the oil agent and heating conditions during spinning, the strength conditions required in post-processing steps such as knitting and weaving can be satisfied. The fiber can be obtained.

Furthermore, since the fiber according to the present invention can be dissolved and removed with hot water or hot water, or further diluted alkaline water,
It is advantageous for industrial use from the viewpoint of wastewater treatment.

As described above, the fiber according to the present invention can be produced by melt spinning with high productivity, and since it has excellent characteristics such as easy handling, it is possible to take advantage of its cold water-insoluble property and hot water-soluble property. It can be widely used for various purposes. For example, fibers for temporary mixing used in processes such as production of base fabric for chemical lace, patterning of knitted fabrics and woven fabrics, separation of socks and sweaters, that is, mixed during weaving, but later removed from the product. It can be widely used as a fiber.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-59-116412 (JP, A) JP-A-61-34278 (JP, A) JP-A-61-296120 (JP, A) JP-A-63- 152624 (JP, A) JP 58-39926 (JP, B2)

Claims (1)

[Claims] 1. A main constituent component of terephthalic acid and ethylene glycol, and 8 to 16 mol% of 5 relative to all acid components.
A substance composed of sodium sulfoisophthalic acid, 5 to 40 mol% of isophthalic acid, and a copolyester containing 0 to 20 wt% of a polyalkylene glycol (number average molecular weight of 400 to 6000) or a derivative thereof based on all polymers. A water-soluble polyester fiber, which is a single-component fiber and has a fiber strength of at least 0.8 g / d.