JPS6155248A - Production of antistatic polyurethane elastic nonwoven fabric - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing an antistatic polyurethane elastic fiber nonwoven fabric.

Conventional Technology A wide variety of nonwoven fabrics have been proposed and used in many fields, but most of these nonwoven fabrics are made of inelastic polymers such as polyamide, polyester, and polyolefin. However, nonwoven fabrics made of highly elastic fibers such as polyurethane elastomers have not been put to practical use.

Furthermore, antistatic nonwoven fabrics made of polyurethane elastomer are not known.

Several proposals have been made regarding nonwoven fabrics made of elastic polyurethane fibers. For example, in Japanese Patent Publication No. 4B-26578, it was proposed to treat a web made of short fibers of elastic polyurethane fibers with aldehyde. There is. Further, Japanese Patent Publication No. 4B-26592 proposes subjecting a web made of short fibers of polyurethane elastic fibers to heat and pressure treatment. In addition, special public service 1972-
Japanese Patent No. 81177 proposes a method in which a polyurethane elastomer is dry-spun to form a web containing a solvent, and then the solvent is removed. However, in either method, the resulting nonwoven fabric tends to have weak bonds between fibers and to be coarse (N11), making it impossible to obtain a high-quality product. Also, the manufacturing process has become complicated. This is extremely disadvantageous in terms of M. Further, no similar efforts have been made to impart antistatic properties.

At present, there is no known method for manufacturing an antistatic polyurethane elastic fiber nonwoven fabric in an industrially advantageous manner.

Problems to be Solved by the Invention Under the current circumstances, the present inventors have carried out intensive research and study on the production of antistatic polyurethane elastic fiber nonwoven fabric, and have completed the present invention.

That is, an object of the present invention is to provide an antistatic polyurethane elastic fiber nonwoven fabric. Another object is to provide an industrially advantageous method for manufacturing such nonwoven fabrics.

Means for Solving the Problems The method of the present invention involves melting a polyurethane elastic material and manufacturing a nonwoven fabric by a melt flow method, by entraining conductive fibers with a high airflow and depositing them together in a sheet form together with the polyurethane elastic fibers. It is characterized by containing 0.05 to 5% by weight of the conductive fiber.

As the polyurethane elastomer applied to the present invention, known segmented polyurethanes can be used, but melt-spuntable thermoplastic polyurethane elastomers are particularly suitable. Such a polyurethane elastomer is composed of a low melting point polyol having a molecular weight of 500 to 6000, such as dihydroxy polyether, dihydroxy polyester, dihydroxy polyether, dihydroxy polyester amide, etc., and an organic diisocyanate having a molecular weight of 500 or less, such as P.

P'-diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, 2,6-diycyanatomethyl caproate, hexamethylene diisocyanate, etc. and molecular weight 50
0 or less, especially polymers obtained by reaction with extenders such as glycols, amino alcohols, or triols. Among these polymers, particularly good are polyurethanes using polytetramethylene glycol, polyε-caprolactone, or polybutylene adipate as the polyol. When polyethylene glycol is used as a polyol, it improves hydrophilicity and is therefore used for special purposes.

Moreover, as the organic diisocyanate, P', P'-diphenylmethane diisocyanate is suitable.

Further, as the chain extender, P,P'-bishydroxyethoxybenzene and 1,4-butanediol are suitable.

The conductive fibers used in the present invention preferably have a single yarn electrical resistance (measured by applying a DC current of 100 V/cIn) of 100 μm or less per atr length.

Such conductive fibers include metals (such as silver, copper,
Thin wires of aluminum, stainless steel, etc.), organic fibers plated with metal or conductive metal compounds (e.g. indium oxide, etc.), and the surface of reinforced fibers? Contains a conductive metal compound (e.g. copper iodide, copper sulfide, indium oxide, etc.) inside.
rJ! , layers formed by chemical means, organic fibers with a conductive resin film containing conductive particles such as carbon blank, conductive polymers (conductive layer) containing conductive particles such as carbon black, and non-conductive Examples include those composited with polymers during spinning. Conductive particles other than carbon blanks include metal particles, metal compound (semiconductor) particles such as zinc oxide, tin oxide, copper sulfide, etc., and inorganic particles such as titanium oxide particles with zinc oxide, tin oxide,
Examples include conductive metal oxides such as indium oxide, and those formed with metal films.

All of the above-mentioned conductive fibers can be used for the purpose of the present invention, but fine metal wires are more difficult to handle than organic fibers, and fibers with a conductive film on their surface tend to have the film peeled off by friction. Most preferred are conductive composite fibers in which a conductive component and a non-conductive component are combined during spinning.

The content of the conductive fibers is preferably 0.05% to 5% by weight, more preferably 4 to 3% by weight of the total weight of the nonwoven fabric. The content varies depending on the type of conductive fiber used, but if the content is small, it will be difficult to obtain the desired antistatic performance.

If the content is too large, the antistatic performance will be improved, but the flexibility and stretchability, which are the most important features of polyurethane elastic fiber nonwoven fabrics, will be impaired, which is not preferable.

The production of the nonwoven fabric of the present invention is preferably carried out using a spinning device equipped with a thermoplastic polyurethane elastomer, a melt extrusion section, a spinning head for the nonwoven fabric, and a device that supplies the conductive fibers with high-speed airflow.

As the spinning head for nonwoven fabric that can be used in the present invention, any known shape can be used, but a spinning head equipped with a nozzle for discharging molten polymer and slits for spouting heated gas on both sides of the nozzle is particularly suitable. A spinning head like this is described, for example, in Japanese Patent Publication No. 7888/1988.

Further, as a device for supplying the conductive fibers, for example, a known air sucker can be used, but it is more preferable to use a device equipped with a yarn speed control so that the amount of supply can be controlled.

How to install the air soccer or how many?

The state of dispersion or content of conductive fibers on the polyurethane elastic fiber non-woven fabric surface varies depending on the amount, but for example, one air sucker is used to make the head shake from side to side.

The method and number of methods include a method of containing the material in a V-shape on the surface of the nonwoven fabric, a method of containing the material in a straight line with several fixed air suckers, or a method of containing the material over the entire surface by swinging several air suckers. It is important to select the appropriate one depending on the intended use of the product.

In addition, it is suitable to install the air sucker either before or after the polyurethane elastic fibers are ejected and collected on the conveyor net. More preferably, the air sucker is installed so that the polyurethane elastic fibers and the conductive fibers are deposited simultaneously on the conveyor net.

A method of depositing the polyurethane nonwoven fabric on a conveyor net, then spraying conductive 1IaHi, and then spraying polyurethane elastic fibers thereon is more preferable because peeling of the conductive fibers is less likely to occur.

An example of an embodiment of the present invention will be described below. Pellets of thermoplastic polyurethane elastomer are fed from a hopper and melted in a heating bath in an extruder. Melting temperature is 190°C ~ 280″
A range of C is preferred. The molten polyurethane elastomer is introduced into the nonwoven fabric spinning head, discharged from the nozzles arranged in rows, atomized by heated high-speed airflow ejected from the slits, and deposited on a moving conveyor net.
be captured.

On the other hand, the conductive fibers pass through a nip roller whose speed is set so as to have a predetermined content, are sucked and ejected by an air sucker, and are deposited on a conveyor net at the same time as the polyurethane elastic fibers.

At this time, it is necessary to set air sucker conditions so that the conductive fibers form random loops on the conveyor net.

The web collected on the conveyor net can also strengthen the bond between the fibers of the nonwoven fabric due to unevenness. Also, any suitable adhesive may be used for the same purpose.

Effects of the invention The nonwoven fabric obtained by the method of the invention has a breaking elongation of 200%.
As mentioned above, the recovery rate at 100% elongation is 85% or more, and due to its excellent elasticity, flexibility, breathability, and antistatic properties, it can be used alone for various purposes, but it can also be used in combination with other materials. By doing so, even more diverse products can be produced. Such materials include inelastic polymers such as polyester,
Examples include woven fabrics, net fabrics, non-woven fabrics, and webs made of synthetic fibers such as nylon, polyolefin, and acrylic, and natural fibers such as cellulose and wool.

Further, films such as polyurethane, foam sheets, etc. may also be used.

Such products are used as materials for various clothing such as sportswear and foundations that require elasticity, as well as interlining, filling, and reinforcing agents.

There are stretch tapes, bands, etc. In addition, it is useful as packing materials, cushioning materials, fillers, and molding materials because it has good fit into various shapes, cushioning properties, and moldability. Furthermore, applications that take advantage of the friction coefficient and wear resistance unique to polyurethane elastic materials include various anti-slip applications such as shoe lining materials.

Furthermore, this nonwoven fabric exhibits particularly excellent effects in fields where antistatic performance is required, making it extremely useful.

The present invention will be described above with reference to Examples.

Example 5550 parts of dehydrated polytetramethylene glycol having a hydroxyl value of 1112 (all parts hereinafter refer to parts by weight).
and 1,4-bis(β-hydroxyethoxy)benzene5
00 parts and 1960 parts of P,P-diphenylmethane diisocyanate were mixed in a Niguu and heated to 85°C to obtain a powdered polyurethane. This was molded into pellets using an extruder. The relative viscosity of @[1F/1i) QC (! in dimethylformamide at 25 °C is 2.01.
Ta.

- A circular cross-section with nylon 6 containing 85% (weight) of carbon black of 10,000, 9 denier and 3 filaments arranged in the center, and nylon 6 containing 0.5% titanium oxide arranged in a sandwich on both sides. The 8-layer conductive composite fiber was crimped. The electrical resistance of this thing is 7.8)/1
It was 0'Ω/cIn.

Pellets of polyurethane elastomer are fed to a melt blow spinning device equipped with slits for jetting heated gas on both sides of nozzles with 0.5φ150 holes arranged in a line in an extruder, and the polymer is spun at a rate of O,:df/m per nozzle. was discharged, and 2000 Mll/m of air heated to 220° C. was injected through the slit to atomize it.

On the other hand, the conductive fibers were also passed through a nip roller set at a predetermined speed, sucked into an air sucker into which the heated air had been introduced, and spouted out while swinging the fibers from side to side. The fine polyurethane elastic fibers and the conductive fibers ejected from the air sucker are simultaneously collected by a conveyor net consisting of a 50-mesh wire mesh installed at 25α below the nozzle.
The basis weight of the nonwoven fabric obtained by sandwiching it between rollers is 80 f/m', and 21! The content of electrically conductive weft fibers was varied. Its characteristics were as shown in Table-1.

The antistatic performance improved as the content of conductive fibers increased. With a content of 0.05%, an effect equivalent to approximately 40% was obtained. However, when the content is 7%, the antistatic performance is very good, but the flexibility and elasticity, which are the greatest features of polyurethane elastic fiber-deficient fabrics, are lost and the product value is low.
Ta.

In addition, the frictional charging voltage is 10 times JI) lI value (20
Table-1

Claims (4)

[Claims] (1) When a polyurethane elastic body is melted and a nonwoven fabric is produced by a melt blow method, conductive fibers are entrained in a high-speed air stream, deposited and collected together with the polyurethane elastic fibers in a sheet form, and the conductive fibers are 0.05% A method for producing an antistatic polyurethane elastic fiber nonwoven fabric, characterized in that the content is 5% by weight. (2) The method according to claim 1, wherein 0.1 to 3% by weight of the total weight of the nonwoven fabric is comprised of conductive fibers. (3) The conductive fiber is a metal fiber, a metal, a metal compound,
The method of claim 1, wherein the fiber has a conductive layer containing conductive particles selected from carbon black. (4) The conductive fiber is a composite fiber in which a fiber-forming polymer is bonded to a conductive layer containing metal particles, conductive metal compound particles, or conductive carbon black particles. the method of.