JPH04185716A - Conjugate elastic fiber - Google Patents

Abstract

PURPOSE:To obtain the subject fiber which is core-sheath type fiber, containing a core component which is a polyurethane resin and a sheath component that is a specific synthetic rubber and excellent in chlorine resistance. CONSTITUTION:The objective fiber containing a core component which is a polyurethane resin and a sheath component that is a synthetic rubber having chlorine resistance. At least part of double bonds in the synthetic rubber are hydrogenated. Furthermore, the chlorine-resistant synthetic rubber preferably has >=.70% strength retention when formed into a film having 50-100mu thickness, stretched at 100% and treated with 60g/l sodium hypochlorite at 50 deg.C for 1hr.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to elastic fibers with excellent chlorine resistance.

(Prior Art) A core-sheath type composite fiber containing polyurethane as a core component and polyamide as a sheath component is described in JP-A-54-138618. Furthermore, in JP-A-54-1, melt spinning of a mixture of plastic polyurethane and thermoplastic synthetic rubber has been proposed.
It is described in Japanese Patent No. 06620.

(Problems to be Solved by the Invention) Elastic fibers (spandex) are made of polyurethane resin, are made into fibers by dry, wet or melt spinning, and are widely used in swimwear, underwear, etc., and are extremely useful. However, one of its major drawbacks is that it becomes brittle due to chlorine.

In other words, sterilizing chlorine in swimming pools damages the elasticity of swimsuits and causes them to stiffen, and bleaching dirty spandex underwear with chlorine bleach causes them to become extremely brittle, making them unwearable and causing stiffness over a long period of time. When washing clothes at home, the chlorine in the tap water can cause them to become brittle. Of course, there are differences in performance depending on the type of polyurethane resin used for spandex, and polyester spandex is generally the best.

On the other hand, among various synthetic rubbers, there are some that have good chlorine resistance, but they are difficult to make into fibers, so they are not used as fibers at present.

(Means for Solving the Problems) As a result of intensive research by the present inventors to eliminate such drawbacks,
This led to the present invention.

That is, in the core-sheath composite fiber, the core component is a polyurethane resin, and the sheath component is a chlorine-resistant synthetic rubber in which at least a portion of the double bonds are hydrogenated.

The double bond referred to in the present invention does not mean an aromatic double bond.

According to the present invention, the shielding effect of the synthetic rubber used in the sheath portion provides good chlorine resistance, and the spinnability of the polyurethane resin in the core allows the synthetic rubber to be made into thread. .

The polyurethane resin used in the present invention may be either thermoplastic or non-thermoplastic, but the former is preferred because it allows for simultaneous combination.

The polyurethane resin used in the present invention is, for example, a carbonate type, an ether type such as polytetramethylene glycol, 3-methyl-1,5-pentanediol, 2methyl-1,8-octanediol, 1,9 - Diols such as nonanediol and anopinoic acid,
Number average molecular weight of polysunil series synthesized from 7-carphonic acids such as azelainoic acid and cepatunoic acid] 000-3500
Chain extenders such as diols and amino acids with a molecular weight of 11,400 or less that have at least two hydrogen atoms that can react with organic disonate and iononanate with a molecular weight of 500 or less (constituting the soft segment). It can be obtained by polymerizing.

Examples of the organic diisonoanate include 4,4'-nophenylmethaneisonanate, and examples of the chain extender include 1,4-butanediol and/or 1,4-his(hydrokinoethoxy)hensen.

In particular, expedient 1 for elastic recovery at temperatures as low as -10°C.
This elastic fiber contains a diol containing 50 mol% or more of 3-methyl-1,5-bentanediol, and a methylene number of 7 to 7 or more, such as azelaino acid and sepanonic acid as a dicarphonic acid component.
Polyester 7 obtained from aliphatic dicarboxylic acid of 10
Obtained from polyurethane resin using resin.

The synthetic rubber with good chlorine resistance used in the present invention is a film with a thickness of 50 to 100μ, and has a strength retention rate when stretched by 00% and treated with sodium hypochlorite 60g/ρ at 50°C for 1 hour. is 70% or more synthetic rubber.

The synthetic rubber used in the present invention may be thermoplastic or non-thermoplastic, and the former is preferred from the standpoint of ease of forming composite fibers with polyurethane resin. It is necessary that at least a portion of the onionic bonds in the synthetic rubber used in the present invention be hydrogenated. Without hydrogenation, spinnability is poor due to cleavage of double bonds. Preferably, 80% or more of the double bonds are hydrogenated.

The synthetic rubber used in the present invention preferably has an elongation (according to JIS) of 400 to 1,000%. Examples of such preferable synthetic rubbers include hydrogenated products of styrene-isoprene multi-block copolymers and hydrogenated products of styrene-butadiene multi-block copolymers.

The molecular weight of these synthetic rubbers is 30.000 to 7D,
DH is preferred. In particular, the former hydrogenated product becomes an ethylene-propylene alternating copolymer (so-called EP rubber) by hydrogenating isoprene and has desirable properties as an elastic body.

The core/sheath (area ratio) is preferably 12 to 52.

If the sheath becomes too thin, the chlorine resistance will decrease, and if the core becomes too thin, the threadability will decrease. The composite fiber of the present invention generally has a single fiber fineness of 5 to 60 deniers.

The composite fiber of the present invention is not limited to one circular shape, but also has an oval shape, a triangular shape,
It can have an irregular cross section such as a square or a cross. Further, the core may be eccentric, or the core may have an irregular shape.

The elastic yarn obtained according to the present invention is coated with other fibers or mixed with other fibers to form a fabric.

Applications of the elastic yarn of the present invention include ski wear, skate wear, swimwear, supporters, car notebooks, pantyhose, leotards, and the like.

Chlorine resistance in the present invention is evaluated by the strength retention rate after chlorine treatment.

・Wrap the chlorinated system in a string shape, wrap it in case, and add 1 of the sodium hypochlorite solution.
% aqueous solution at 25° C. for 72 hours, then washed with water and air-dried.

・Strength measurement and strength retention The strength before and after chlorination was measured using an Instron 1" 22 type tensile tester at a tensile speed of 50 cm/min in accordance with JIS.

Strength retention rate - breaking strength after treatment/breaking strength before treatment The present invention will be explained below with reference to Examples.

(Examples I to 3) A hydrogenated poly-styrene-isoprene-styrene triblock polymer with a chlorine resistance strength retention rate of 80% (yearly average amount + 150,000) was used as the sheath component, and a poly-styrene-styrene triblock polymer as the core component. An elastic yarn having a sheath/core ratio of 1/2 to 2/1.40 dr was obtained using thermoplastic polyurethane having a soft segment of 3-methylpentane azelade (molecular weight 1800).

For spinning, the sheath component was extruded using a single-screw extruder, and the core component was extruded using a twin-screw extruder. Add a mixture (reactant) of MDI (hereinafter abbreviated as MDI) and poly-3-methylpentane azelade (molecular weight 2, O [lD) at a molar ratio of 20 so that the NCO group (10) I group ratio = 1.04, The mixture was kneaded and extruded, then spun using a conventional composite spinning machine at a spinning temperature of 230° C. and wound at a spinning speed of 500 m/min.

The wound yarn was left to cool at 80° C. for 24 hours in air with a dew point of −20° C., and then a chlorine resistance test was conducted.

The results were good as shown in Table 1. However, the elastic recovery of this yarn at 200% elongation at ~10°C is 9.
It was good at 0%.

(Example 4) Polytetramethylene glycol (molecular 1150
0) is a thermoplastic polyurethane with a soft segment, the sheath/core ratio is l/2, and the additive is MDI.
Elastic yarn was obtained in the same manner as in Example 1, except for using the molar ratio of polytetramethylenenoglycol (molecules! 5H) = lu) mixture (reactant), and the chlorine resistance was evaluated. The results are good, as shown in Table 1.

(Comparative Example 1) Polyurethane elastic yarn (spandex, 40 denier) was obtained by extruding only the core component without extruding the sheath component in Examples-1 to 3, and Agi
ngL, chlorine resistance test was conducted. As shown in Table 1, the results were not satisfactory.

(Comparative Example 2) When only the core component of Example 4 was spun and aged in the same manner as in Comparative Example 1 and a chlorine resistance test was conducted, the yarn fell apart and the strength could not be measured. .

(Comparative Example 3) Commercially available dry-spun polytetramethylene glycol spandex (40 denier) was obtained and its chlorine resistance was evaluated. The yarn was so tattered that it was impossible to measure the strength. Below is a margin table. 1 Comparative Example 5 Example I
When trying to obtain a sheath-core yarn in the same manner as f2, the molecular weight decreased due to the cleavage of the double bond in the isoprene block,
Spinning was impossible due to poor extrusion.

Comparative Example 6 An attempt was made to spin a poly-styrene-butanene-styrene triblock polymer (molecular weight 52,000) as a sheath component in the same manner as in Example 1, but crosslinking occurred due to thermal cleavage of the double bond in the butadiene block. A reaction occurred and it turned into a gel, making it impossible to spin.

Patent applicant RiRashi Co., Ltd.

Claims (1)

[Claims] (1) A core-sheath type composite elastic fiber in which the core component is a polyurethane resin and the sheath component is a chlorine-resistant synthetic rubber in which at least a portion of the double bonds are hydrogenated.