JPH05272006A - Hydraphilic polyolefinic fiber - Google Patents

Abstract

PURPOSE:To enable not only polyethylene fiber but also polypropylene fiber itself to have sufficient hydrophilicity and prevent undesireable effects of smoking an producing them. CONSTITUTION:The objective hydrophilic polyolefinic fiber is produced by blending a polyolefin containing propylene or ethylene as a principal monomer component with Na salt of an alkylsulfonate in an amount of 0.5-5wt.% based on the total amount of the Na salt of the alkylsulfonate and the polyolefin. Since the hydrophilic polyolefinic fiber of this invention has sufficiently lasting hydrophilicity even in the case of polypropylene fiber, the polyolefin fiber is formed into a nonwoven fabric and used for applications of skin materials such as a paper diaper to always rapidly pass urine therethrough, etc., without causing disorders such as contact dermatitis. Since the hydrophilic polyolefinic fiber can be produced in a good environment without smoking, the production can be increased to further extend uses as the skin materials for disposable sanitary materials such as the paper diaper.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a hydrophilic polyolefin fiber containing propylene or ethylene as a main monomer component.

[0002]

2. Description of the Related Art Fibers produced from polyolefins containing propylene or ethylene as a main monomer component, so-called polypropylene fibers and polyethylene fibers, are widely used for various purposes, but they are used as a non-woven fabric for skin materials of disposable hygiene products such as disposable diapers. It is also widely used as a raw material fiber. A sanitary article such as a paper diaper is composed of an epidermis material that comes into contact with the skin and an absorbent material thereunder, and urine or the like passes through the epidermis material and is absorbed by the absorbent material. The basic requirement that such a sanitary article should have is that it does not cause rash, swelling, or other problems due to discharged urine or the like. Problems such as a rash occur when the discharged urine or the like is not completely absorbed by the absorbent and remains on the surface of the skin material. Therefore, in order to eliminate such obstacles, it is important that almost no urine or the like passes through the skin material promptly, and for that reason, urine or the like easily penetrates between the fibers of the skin material and passes. It is necessary to have hydrophilicity.

Polypropylene fibers and polyethylene fibers are hydrophobic in nature and are not suitable for use as a skin material.
Normally, these short fibers are coated with an oil containing a surfactant as a main component during fiber production to impart hydrophilicity to the surface of the fibers, so that the skin material is not subjected to treatment such as washing until commercialization. It can be used as a raw material for nonwoven fabrics. However, even in this case, if the oil agent component on the fiber surface is washed away by the first urination after wearing as a disposable diaper or the like, then the hydrophilicity is reduced thereafter.

A nonwoven fabric processed by a spunlace method in which a fibrous web is entangled with a high-pressure water stream loses its hydrophilicity by washing away the oil component on the surface of the fiber due to the above-mentioned water flow. is necessary. Further, the nonwoven fabric obtained by spinning with a high-speed air stream by the spunbond method and then made into a non-woven fabric is not hydrophilic because it does not use an oil agent during spinning, and can be used only in a limited part of the skin material There are problems such as need.

In recent years, such a problem has been found in polyolefin-specific wetting agents (glyceride and alkoxylated phenol, or polyoxyalkylene fatty acid ester alone,
Alternatively, a proposal has been made to solve the problem by producing a fiber from a composition obtained by adding a mixture of these and making the fiber itself hydrophilic (JP-A-60-194113). However, when the polypropylene fiber or the polyethylene fiber is made hydrophilic by the above wetting agent, the polyethylene fiber exhibits sufficient hydrophilicity, but the polypropylene fiber has insufficient hydrophilic performance. In addition, there is a drawback in that the wetting agent causes a lot of smoke to be emitted from the nozzle during spinning, which lowers the spinning performance and deteriorates the spinning work environment.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain hydrophilic polypropylene fibers and polyethylene fibers which have solved the above-mentioned drawbacks of the prior art.

[0007]

Means for Solving the Problems As a result of various studies, the present inventor has found that the above problems can be achieved by using an alkyl sulfonate Na salt as a compounding agent for imparting hydrophilicity to polypropylene and polyethylene. And completed the present invention. That is, the present invention provides a hydrophilicity prepared from a composition obtained by blending a polyolefin containing propylene or ethylene as a main monomer component with an alkyl sulfonate Na salt in an amount of 0.5 to 5% by weight based on the total amount of the polyolefin. It relates to a polyolefin fiber.

The polyolefin containing propylene or ethylene as a main monomer component, so-called polypropylene or polyethylene, used in the present invention is a crystalline polymer obtained by using a generally known Ziegler-Natta catalyst, and if it is only a homopolymer. No small amount, for example 0.1
Also included are copolymers with .about.10% by weight .alpha.-olefins such as ethylene, propylene, butene-1 and the like. The MFR of the polypropylene used in the present invention (ASTMD123
8 conditions L) and polyethylene MI (ASTM D123
8 Condition E) is not particularly limited, but it is preferable for spinning to use polypropylene having MFR of 5 or more and polyethylene having MI of 10 or more.

The alkyl sulfonate Na salt used in the present invention has the structure of the following formula (I). R in the _{R-SO 3 Na ··· (I} ) above formula represents an alkyl group. The C number of R is preferably 10 to 20. The amount of the alkyl sulfonate Na salt to be added to the polyolefin is appropriately 0.5 to 5% by weight based on the total amount of both. If the blending amount is less than 0.5% by weight, hydrophilicity will not be expressed to an effective degree. Further, even if the blending amount exceeds 5% by weight, the effect of increasing the amount is hardly recognized, but the yarn breakage during spinning is increased.

The composition of the present invention is mainly composed of the above-mentioned blend of polyolefin and Na salt of alkyl sulfonate, and various additives such as stabilizers, lubricants, pigments and radical generators such as peroxides. Can be contained within a range that does not impair the effects of the present invention. In order to obtain the composition of the present invention, polypropylene or polyethylene is added with an alkyl quisulphonate Na salt and, if necessary, the above-mentioned various additives, and a known mixing apparatus such as a Henschel mixer, a super mixer, a ribbon blender or a Banbury mixer is used. Mixing using a known single screw extruder, 2
Melt temperature with axial extruder, Brabender or roll
Melt-kneading and pelletizing at 150 ° C to 300 ° C, preferably 180 ° C to 250 ° C.

The hydrophilic polyolefin fiber according to the present invention is a fiber having a uniform phase throughout the whole without having a specially divided structure in its cross section. Such hydrophilic polyolefin fibers can be produced from the composition obtained as described above by a known melt spinning method. For example, with an extruder equipped with a spinning nozzle, the composition is melt-kneaded at an extrusion temperature of 190 ° C. to 300 ° C. and extruded from the spinning nozzle, and the extruded molten resin is taken up by a roll to obtain an undrawn yarn. To manufacture. Then, this unstretched yarn is stretched several times while being heated using a hot roll, a hot plate, a hot-air heating furnace, etc., and then crimped by a crimping device if necessary to make a short fiber. Cut to length.

[0012]

EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples, but the present invention is not limited thereto. In addition, the measuring methods or definitions of the physical properties shown in the examples are collectively shown.

MFR: ASTM D1238 Condition L MI: ASTM D1238 Condition E Hydrophilicity: A fiber bundle is prepared to have a length of 10 cm and a weight of 6 g, and twisted 4 times. Droplets are attached, and the permeability of the ink into the fiber bundle is visually evaluated based on the following criteria. ⊚: Permeates quickly. ○: Penetrate within 5 seconds. Δ: Penetration takes 5 seconds or more. X: Does not penetrate.

Spinnability of the composition: Extrusion temperature of 250 ° C., extrusion amount of 0.5 g / min per hole, spinning speed (same as winding speed) of 800 m / min per 60 minutes when spun. Evaluation is made based on the following criteria according to the number of yarn breaks. ○: The thread was not broken. X: One or more thread breaks. Smoke emitting property: The smoke emitting property at the nozzle was changed to alkyl sulfonate Na under the same spinning conditions as the spinnability evaluation.
The comparison with the smoke-producing property of the raw material to which no salt is added is visually observed and evaluated based on the following criteria. ◯: Smoke emission equivalent to that of no addition. Δ: Some more than not added. X: Remarkably more than no addition.

Examples 1 to 3 and Comparative Examples 1 to 3 Powdered polypropylene (homopolymer) of MFR10 was blended with a predetermined amount of the alkyl sulfonate Na salt shown in Table 1 and added to 100 parts by weight of the blend. On the other hand, 0.1 part by weight of BHT (bruchylated hydroxytoluene) and 0.1 part by weight of calcium stearate were added and mixed for 1.5 minutes with a Henschel mixer, and then 200 ° C with a single screw extruder having a diameter of 40 mm.
Was melt-kneaded and pelletized to obtain a composition as a spinning raw material.

The pellets thus obtained are extruded at an extrusion temperature of 250 ° C. from a melt spinning machine equipped with a spinning nozzle having a hole diameter of 1 mm and 100 holes, and a spinning speed of 800.
Melt spinning was performed under the condition of m / min to produce an undrawn multifilament consisting of 100 fibers of 5.6 denier. In the above process, an oil agent was attached to the fiber surface to reduce friction with the guide. Then, in order to evaluate the spinnability of the composition used as the spinning raw material, the spinning time and the number of yarn breakages were counted. A portion of this unstretched multifilament was stretched on a hot plate heated to 100 ° C under the conditions of a final stretching speed of 60 m / min and a stretching ratio of 3 times to produce a stretched multifilament composed of 100 1.9 denier fibers. .. In this way, hydrophilic polyolefin fibers according to the present invention and comparative fibers (two types of undrawn yarn and drawn yarn exist for each) were obtained.

50 g of each of the obtained unstretched and stretched multifilaments was washed with water to wash off the oil component,
After drying for 12 hours with a hot air dryer at ℃, hydrophilicity was evaluated. The results of the composition's spinnability, smoke generation and fiber hydrophilicity are shown in Table 1.

Examples 4 to 6 and Comparative Examples 4 to 6 Examples 1 to 1 except that powdered polyethylene having a MI of 16 (homopolymer) was used in place of the powdered polypropylene.
3, In the same manner as in Comparative Examples 1 to 3, the spinnability and smoke generation of the composition used as the spinning raw material were examined, and the hydrophilicity of the obtained hydrophilic polyethylene fiber and the comparative fiber was measured.
The results are shown in Table 2.

[0019]

[0020]

As can be seen from Tables 1 and 2, the polypropylene fiber and polyethylene fiber obtained from the composition containing the alkyl sulfonate Na salt in the amount defined in the present invention are excellent in hydrophilicity and The spinnability is also sufficient, and even if there is no smoke during spinning, it does not pose a practical problem, and industrial production is possible. On the other hand, when the alkyl sulfonate Na salt is not contained, or even when it is contained in a content outside the range specified in the present invention, the hydrophilicity is insufficient, or even if it is sufficient, the spinnability is insufficient. It turns out that it is defective and cannot be put to practical use.

[0022]

EFFECT OF THE INVENTION The hydrophilic polyolefin fiber according to the present invention has not only polyethylene fiber but also polypropylene fiber having sufficient permanent hydrophilicity to the fiber itself, and can be produced without adverse effects of smoking during spinning. is there. When such a hydrophilic polyolefin fiber according to the present invention is made into a non-woven fabric and used as a skin material such as a paper diaper, the hydrophilic property is maintained good even after the first urination after washing or wearing in the manufacturing process. Therefore, it always passes urine etc. quickly, does not cause problems such as rashes, and can be produced in a good environment without smoke, so increase the production amount and use it as a skin material for sanitary materials. The application can be further expanded.

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Claims (2)

[Claims] 1. A polyolefin containing propylene or ethylene as a main monomer component, and an alkyl sulfonate Na salt in an amount of 0.5 based on the total amount with the polyolefin.
A hydrophilic polyolefin fiber produced from a composition obtained by blending 5 to 5% by weight. 2. The alkyl sulfonate Na salt has an alkyl group R having 10 to 20 carbon atoms in the formula (I) R—SO ₃ Na ... (I). The hydrophilic polyolefin fiber described in 1.