JPS61132627A - Production of conjugated fiber - Google Patents

Abstract

PURPOSE:An undrawn conjugated fiber which is composed of, e.g., a thermoplastic elastomer and polyamide is heat-treated and spun under specific conditions to give conjugated fiber which is suitable for use in weaving and knitting, because it does not cause reduction in crimping development, even after storage in its pirn form for a long period of time with high crimpability and opening properties. CONSTITUTION:An undrawn conjugated yarn of side-by-side or eccentric sheath- core structure is prepared from (A) a thermoplastic elastomer, preferably polyurethane or nylon 12 elatomer and (B) a polyamide (nylon 6) or polyester (polyethylene terephthalate) and the yarn is heat-treated at 90-130 deg.C for 30-90 minutes, then drawn according to the usual method to give the objective fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This book 1F14 relates to a method for producing composite fibers, and in particular to a method for producing composite fibers with excellent crimp performance that are suitably used in woven and knitted fabrics.

[Prior art]

Conventionally, many crimped yarns made of fibers made by combining two types of polymers with different shrinkage characteristics in a side-by-side type or an eccentric sheath core type have been proposed and used. In particular, in minute hands such as pantyhose which require high elasticity, composite fiber crimped yarns of thermoplastic elastomer and polyamide or polyester are used.

These conventional composite fiber manufacturing methods involve combining two types of polymers with different heat shrinkage characteristics in a spinneret in a side-by-side temperature or eccentric sheath core type, and winding the resulting undrawn yarn into a predetermined shape. Generally, the material is stretched to a stretching ratio of 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000, and then wound.

Among these methods, the method of winding after stretching has a relatively low crimp performance of the wound yarn, especially if it is left for a long time after winding.
There is a problem that the crimp development performance deteriorates with the passage of time, and this presents a fatal drawback when used after long-term storage. In addition, the method of performing relaxation heat treatment after stretching may cause the constituent fibers of the multifilament to contact and interfere with each other during the relaxation heat treatment, resulting in overlapping of the fibers in opposite phases in the miscellaneous fibers, and as a result, the fiber opening state may be uneven. Therefore, there is a problem in that it is easy to cause defects such as pickets and spots on the grain surface of the woven or knitted fabric.

[Purpose of the invention]

The present invention consists of 1. This was developed to solve the problems of the conventional technology as described above, and it is a composite fiber that has excellent crimp performance and opening performance, and has little deterioration in crimp performance even when stored in a rolled state for a long period of time. The company provides the manufacturing of

[Details of the invention]

The present inventors have conducted intensive research on the deterioration of the crimp performance over time after drawing in composite fibers of thermoplastic elastomer and polyamide or polyester, and as a result, the shrinkage performance of the elastomer, which is caused by the high crimp component, has decreased over time. The inventors have found that the difference in shrinkage between the elastomer and the low-shrinkage component polyamide or polyester decreases over time, resulting in a decrease in crimp development. Furthermore, the reason why the shrinkage performance of elastomers decreases is that in the conventional method of stretching undrawn yarn as it is, the elastomer molecules that are in a stretched state due to stretching leave many unstable states where partial crosslinking occurs over time. The present invention has been arrived at as a result of various studies on the conditions for undrawn yarns that do not leave the above-mentioned unstable state after drawing.

[Structure of the invention]

The present invention provides an undrawn yarn of a composite fiber in which a thermoplastic elastomer and a polyamide or polyester are composited in a side-by-side type or an eccentric 7-score type.
The present invention is a method for producing composite fibers characterized by heat treatment at 50° C. and then stretching, and with this configuration, the above object is achieved.

That is, the present invention heat-treats the undrawn yarn of the composite fiber at 70 to 150°C before drawing to cause molecular crosslinking in the elastomer component, thereby preventing the remaining unstable state of molecular crosslinking after drawing. is eliminated, and the shrinkage performance of the elastomer is maintained for a long period of time.
The shrinkage difference with polyamide or polyester, which is a low-shrinkage component, does not decrease, and the crimp performance of the composite fiber remains high and unchanged.

In the present invention, the thermoplastic elastomer used as one component of the composite fiber is an elastomer that can be melt-spun, and has a total hardness of 90 to 100 on a rubber hardness meter and a melting point of 200 to 240°C. Preferably used. Examples of such thermoplastic elastomers include polyurethane elastomers and polyamide elastomers. Among these, polyurethane elastomers are made of polyesters with terminal hydroxyl groups, poly(oxyalkylene) glycols with a molecular shield of 1,000 to 3,000, diisocyanates and glycol chain extenders, and in some cases polycarbonates with terminal hydroxyl groups. Additionally, it is a thermoplastic polyurethane obtained by reaction. As polyesters, dibasic acids such as adipic acid and sebacic acid and diols such as ethylene glycol, butylene glycol, and diethylene glycol are used as polyesters, and as poly(oxyalkylene) glycols, poly(oxyethylene) glycol and poly(oxypropylene) are used as polyesters. ) glycol.

Block copolymers or homopolymers such as poly(oxybutylene) glycol are used. And, as diincyanate, 2,4-tolylene diincyanate,
Diphenylmethane-4,4'-diincyanate, dicyclohexylmethane-4,4'-diincyanate, etc. are used, and chain extenders such as toshite, ethylene glycol, propylene glycol, butylene glycol, 1,4-β are used.
-Hydroxyethoxybenzene can be used. The optionally used polycarbonate must also be polymerized from bisphenol A and phosgene or bisphenol A and diphenyl carbonate and have terminal hydroxyl groups.

Polyamide yarn elastomers are commonly copolymers of polylauryllactam and dicarboxylic acids of polybutylene glycol (produced from 1,4 butanediol).

The hardness of this elastomer can be varied by varying the molecular weight of butylene glycol, which is the rubber component, and can also be varied by varying the copolymerization ratio of polylauryllactam and the rubber component.

Polyamides used as the other component of the composite fiber include nylon 6, nylon 66, nylon 6, and 10.
, nylon 11. Nylon 12. Nylon 13 or the like can be used, and polyesters such as polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, and preferably those obtained by copolymerizing these with 5-sodium sulfoisophthalate are used.

The above-mentioned combination of the two components of the composite fiber has good compatibility and adhesion when pasting together, so that the two components do not peel off during processes such as spinning, grinding, thread processing, and weaving. It is necessary to choose. In particular, when polyester is used as one of the components, it is preferable to use a polyester yarn elastomer, such as a block copolymer of polyether and polyester, as the thermoplastic elastomer. Further, when a polyester component obtained by copolymerizing the above-mentioned 5-sodium sulfoisophthalic acid is used, the bonding adhesiveness is improved. If polyamide is used as one component,
As the thermoplastic elastomer, it is preferable to use caprolactone-based or polycarbonate-based polyurethane or polyamide-based elastomer, such as a copolymer of polylauryllactam and polyol. In order to improve light resistance, a light resistance improver such as a benzophenone compound, a benzotriazole compound, or an inorganic manganese compound may be added to these elastomers and polyamides.

Side-by-side type or eccentric sheath core type composite fibers are spun using both of the above components, but in the case of eccentric sheath core type, the core is a thermoplastic elastomer which is a high shrinkage component to improve crimp development. It is preferable from the viewpoint of fiber properties and the like. This spinning is performed in the same manner as conventional composite fiber spinning.

The most important feature of the present invention is that the obtained undrawn yarn is heat-treated at 70 to 150° C. under a fixed length prior to drawing. This heat treatment of undrawn yarn under a fixed length is usually performed while it is being wound into a package, and the free length after heat treatment is 1 compared to the initial free length.
Conditions of elongation or contraction of 0% or less are included.

On the other hand, if heat treatment is performed under stretching conditions where the elongation after heat treatment is greater than 10%, many elastomer molecules will be crosslinked, resulting in a decrease in the control rate of the elastomer after stretching, and as a result, the crimp development of the composite fiber will decrease. descend.

Furthermore, if the heat treatment is performed under relaxed conditions in which the shrinkage after heat treatment is greater than 10%, the stretchability of the polyamide or polyester component will be poor, which is not preferable. If the heat treatment temperature is lower than 70°C, crosslinking of the elastomer molecules will not proceed, and it will not be possible to prevent the contraction performance of the elastomer from decreasing over time after stretching.
If the temperature is higher than 50° C., the elastomer component may melt, which tends to cause problems such as adhesion between fibers and breakage of undrawn yarn during drawing. The preferred range of heat treatment temperature is 90 to 130°C.

Further, the heat treatment time is preferably in the range of 10 to 120 minutes, and particularly preferably in the range of 30 to 90 minutes.

If the spinning time is less than 10 minutes, the effect will be small, and if it is longer than 120 minutes, the oil and moisture applied during spinning will be lost, resulting in a decrease in the drawability of the undrawn yarn. Furthermore, although the heat treatment atmosphere may be heated air, it is preferable to use an inert gas atmosphere such as N2 to prevent yellowing of the polymer or oil agent.

This is preferable in terms of preventing deterioration.

The heat-treated undrawn yarn may be stretched in one stage or in multiple stages, as in conventional stretching, and even if relaxation heat treatment is performed after stretching, the effect of the present invention may increase but disappear. I will not be forced to do so.

Note that the spinning speed and drawing speed of the conjugate fiber in the present invention are not particularly limited, and the same speeds as conventional ones can be adopted.

〔Example〕

Example 1 Using commercially available polyurethane (Elastlan E 595 manufactured by Nippon Elastran Co., Ltd.) as a thermoplastic elastomer,
NycP75 (intrinsic viscosity (η)) as a polyamide component
= 1.1) at 225°C and 2
JP-A-57, which was melted separately at 50°C and heated to 240°C.
A side-by-side type composite fiber was spun using a spinneret having three discharge ports as shown in FIG. 4A of Publication No. 205520. At that time, the polymer discharge rate was 2.55'/min, and the spinning oil was applied for 500 m.
It was wound up in 7 minutes to obtain an undrawn yarn package. The obtained undrawn yarn was heat-treated in a packaged state (in an N2 atmosphere). The heat treatment temperature and time were variously changed. The heat-treated undrawn yarn was drawn at a drawing speed of 500 m/min and a drawing ratio of 3.7.
Cold-stretched in one stage at a double speed, wound on a bobbin to 25 denier/3
A composite multifilament yarn of filaments was obtained.

30 packages of the resulting composite multifilament yarn
Table 1 shows the results of measuring the rate of crimp development after 1, 10, and 30.90 days of leaving the sample in a room at ℃.

Incidentally, the crimp development rate was measured by the following method.

The sample was 0. It is wound 10 times with a total number of about 40 cm under tension of I V/ae to about 500 denier (25 x 10
I made the total of X2). A load of 2■/de was suspended on the whole, immersed in purified water for 20 minutes, the load was removed, and the
Air dry indoors at 5% RH for 24 hours. After drying, the sample was again subjected to a load of 2 ■/de and a load of 0.1 P/de, and the length 1a (C1N) was measured after 2 minutes. The load is removed and the length l (cm) is measured after a further 2 minutes have elapsed. Crimp incidence: IQQ X (10-t, )/lo (%)
shall be.

Margin Example 2 below. - Nylon 12 thread elastomer commercially available as a thermoplastic elastomer (Daicel Chemical Co., Ltd. Diamid X-3978)
Nylon 6 (intrinsic viscosity (
+7)=1.13, respectively at 240℃ and 2
Composite fibers were spun using the same spinneret as in Example 1, which was heated separately at 50° C. and 250″ CIC.The discharge amount and spinning oil were as follows.

The winding speed was the same as in Example 1. The resulting package of undrawn yarn was heat-treated at 110"C for 60 minutes in an N2 atmosphere, and the heat-treated undrawn yarn was drawn under the same conditions as in Example 1. On the other hand, as a comparative example, the undrawn yarn without heat treatment was also the same. The crimp development rate of the obtained drawn yarn was measured in the same manner as in Example 1, and the results are shown in Table 2.

Table 2 [Effects of the Invention] According to the present invention, as is clear from the results in Tables 1 and 2, the crimp level of the composite fibers immediately after production is improved, and An excellent effect is obtained in that the crimp level hardly decreases even if the composite fiber is left for a long period of time. Therefore, when using the composite fiber obtained by the method of the present invention, it is possible to Even if composite fibers are used that have different storage periods from manufacture to use, unevenness will occur in the woven or knitted fabric due to changes in crimp development over time. There is also a great economical effect in that the remaining yarn can be used together with new yarn. Another advantage is that there is no need to strictly control the storage period and storage conditions of the composite fibers.

Claims (4)

[Claims] (1) An undrawn yarn of a composite fiber made of a thermoplastic elastomer and polyamide or polyester combined in a side-by-side type or eccentric sheath core type with a fixed length of 70 to 150
A method for producing composite fibers, which comprises heat-treating at ℃ and then stretching. (2) The method for producing composite fibers according to claim 1, wherein the thermoplastic elastomer is polyurethane. (3) The method for producing composite fibers according to claim 1, wherein the thermoplastic elastomer is a nylon 12-based elastomer. (4) The method for producing composite fibers according to claim 1, wherein the heat treatment temperature is 90 to 130°C.