JPH04289238A - Opening of polyester-based multifilament bundle - Google Patents

Abstract

PURPOSE:To open no-twist polyester-based multifilament bundle into an electrostatically charged monofilament state without using a high-voltage applying device. CONSTITUTION:No-twist polyester-based multifilament bundle is passed through a metallic Nerson roll in an atmosphere of 0.024kg-H2O/kg-dry air absolute humidity so as not to twist the bundle, frictionally charged by contact and release from the metallic roll and then passed through an air gun spraying compressed air to open the bundle into a monofilament state.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for opening untwisted polyester multifilament fibers by frictionally charging them and opening them into monofilaments using compressed air. The filament bundle opened by the method of the present invention can be collected in the form of a sheet and processed into a nonwoven fabric by adhesion or entanglement.

0002

[Prior Art] Among the methods of opening continuous multifilament fiber bundles, the most proposed one at present is a method in which the multifilament surface is charged with static electricity of the same polarity and the fibers are opened using the Coulomb repulsion force. There is. These methods can be broadly classified according to the method of applying static electricity to the multifilament; methods of applying static electricity to the multifilament bundle by directly or indirectly applying a high voltage to the multifilament bundle from the outside;
There is a method of applying static electricity to the filament bundle by friction with high-speed air or a guide, or by friction due to collision with a collision plate, or by contact peeling.

In the former method, for example,
Publication No. 93, Special Publication No. 63-16503, Special Publication No. 16503, Special Publication No. 16503
There are Japanese Patent Publication No. 3-42016, Japanese Patent Application No. 2-172466, etc., and the latter method is disclosed in Japanese Patent Publication No. 37-4993,
These include Japanese Patent Publication No. 52-8430, Japanese Patent Publication No. 1-15615, and Japanese Patent Application No. 1989-108175. Both methods are proposals for opening polyester multifilament bundles.

0004

According to the studies conducted by the present inventors, it has been found that the above-mentioned prior art has the following problems. In other words, the method of forcibly applying a high voltage from the outside to a multifilament bundle requires a very high voltage to effectively charge the filaments, which is not only dangerous, but also requires a large amount of equipment such as power supplies and safety equipment. A common problem is that it requires a large amount of effort.

On the other hand, Japanese Patent Publication No. 1-15615 and Japanese Patent Publication No. 52-84 utilize a charging method based on friction and contact peeling.
No. 30 proposes a method of charging a filament bundle by frictional charging using high-speed air or by collision with a plate or the like with high-speed air. In these cases, it is possible to charge the filament bundle relatively easily, but
In order to charge the filament sufficiently to spread it, a fairly high-speed air flow is required, and these air flows have a significant effect of disturbing the flow of the opened filament, making it impossible to obtain stable and good opening. . Furthermore, the cost of supplying high-speed air is large, so this is not an economical method.

[0006] Furthermore, Japanese Patent Publication No. 37-4993 proposes applying static electricity to a filament bundle using only charging caused by friction between a fixed friction element and a filament bundle. In order to charge the yarn effectively, the tension applied to the yarn must be quite high, and during long-term continuous processing, changes in the frictional state due to wear of the friction elements, or effects such as abrasion on the multifilament bundle can cause fiber opening. This makes the stable continuous process of the process extremely unstable.

The present inventors have disclosed in Japanese Patent Application No. 2-108175 that fiber bundles are formed by passing a multifilament bundle between a drivingly rotating metal roll and a nip roll whose surface is coated with an elastomer that rotates due to friction between the metal rolls. We proposed a method to open multifilament bundles by frictional contact peeling charging. It has been found that this method is not necessarily a very efficient method for charging polyester multifilament bundles. The reason for this is presumed to be that the triboelectric series of the polyester and the elastomer are close to each other.

The present invention solves the above-mentioned problems of the prior art, and allows polyester multifilament fiber bundles to be continuously charged by frictional contact peeling and opened into monofilaments in a safe and stable manner using relatively simple equipment. The purpose is to provide a method.

[0009]

[Means for Solving the Problems] The present invention provides untwisted polyester multifilament bundles with an absolute humidity of 0.024K.
The material is passed through a metal nelson roll in an atmosphere of g-H2O/kg-dry air or less without twisting, and frictionally charged by contact peeling with the metal roll, and then passed through an air gun that is injecting compressed air. This is a method for opening a polyester multifilament bundle, which is characterized by opening the bundle into a monofilament.

[0010] The untwisted polyester multifilament bundle referred to in the present invention is a fiber bundle formed from a polymer in which monomer molecular chains are connected by ester bonds, and which has been made into continuous filaments by drawing, heat treatment, etc. Basically, it refers to a fiber bundle that has no twists or entanglements between filaments, and that has not been twisted by twisting operations. Examples include polyethylene terephthalate, polybutylene terephthalate, and polyarylate multifilament bundles. It is also a modified polyester multifilament that is copolymerized or added with various other general modifying components.

[0011] In the present invention, a polyester multifilament bundle is electrostatically charged by friction or contact peeling, and then opened into a monofilament form by Coulomb repulsion. The multifilament bundle is wound several times around a driving metal roll and a separate roll, which have different charging properties in terms of electrification series, in a nelson-like manner to prevent twists from being mixed in, and is driven and taken off without slipping. The multifilament bundle is charged to a high voltage due to repeated contact and peeling between these metal rolls and separate rolls. Since charging is carried out by such a method, there is almost no change in the state of the charging section as in conventional frictional charging with a completely fixed friction element, and stable continuous processing is possible. Of course, it is also possible to carry out the charging process by using a conventional friction element in combination. In this case, contact peeling between the rolls can significantly reduce the tension applied to the filament bundle, which reduces problems such as wear of the friction elements and fuzzing of the filament bundle, making it possible to perform stable and continuous charging processing. . Wrapping the multifilament bundle in a nelson-like manner between a driving metal roll and a separate roll prevents tension fluctuations on the supply side of the multifilament bundle from affecting the opening section, and also stably supplies the filament bundle to the air gun, reducing the It is also important for stably opening the fibers under tension.

[0012] The filament bundle that has passed through the Nelson roll is charged to a high voltage, and by bringing it into a low tension state, it can be opened to some extent as it is, but in order to advance the charged filament bundle and bring it into a low tension state, it can be opened sufficiently. It is necessary to pass the air gun. The charged filament bundle is sucked by an air gun and injected with an air stream, and as it moves forward, it becomes almost tensionless and is opened into a monofilament shape due to the repulsive force of static electricity and the scattering action of air.

[0013] Since the filament bundle is driven by the Nelson roll and supplied to the air gun, the air gun does not require a strong suction force to forcibly take over the filament bundle and drive it forward; It can be sucked and moved forward with a weak suction force that does not wrap around rolls. In other words, the amount of air blown into the air gun is small, which is not only economical, but also eliminates the phenomenon of disturbing the opened filament flow and collection web as in the conventional technology because the air flow emitted from the air gun is small. be done.

Next, an important point in the present invention is to reduce the absolute humidity of the working atmosphere in which the polyester multifilament bundle is opened. In the present invention, the surrounding atmosphere during contact peeling charging using a Nelson roll and opening using an air gun is 0.024 kg-H2O/kg.
-dry air or less, preferably 0.01kg-H2
O/kg-dry air or less. The absolute humidity of the surrounding atmosphere is 0.024kg-H2O/kg-dry ai
If it is higher than r, the multifilament bundle becomes difficult to be electrostatically charged due to friction or contact peeling. Furthermore, even if the multifilament bundle is charged, the charge tends to escape, making it difficult to spread the multifilament bundle into a monofilament shape due to the charging repulsion force. This is due to water vapor in the atmosphere adsorbing water on the surface of the device or promoting discharge.

The opened filaments obtained by the method of the present invention are deposited on a collecting device in the form of a wire mesh belt conveyor that is continuously moved by the amount of air discharged from an air gun to form a web, and then subjected to calendering, A filament nonwoven fabric can be obtained by adhering or entangling the fibers by methods such as needle punching or adding a binder.

[0016]

[Examples] Next, the embodiments of the present invention will be explained using specific examples, but the present invention is not limited by these examples.

Example 1, Comparative Example 1 A non-twisted multifilament bundle (300 dr/144 f) of polyethylene terephthalate was heated to an absolute humidity of approximately 0.010 kg-H2O/kg-dry air using the apparatus shown in FIG.
When a fiber opening test was carried out under an atmosphere of 1,000 m/min at a yarn processing speed of 1000 m/min, a good fiber opening state could be stably obtained for a long time with an air flow rate of 0.20 Nm3/min. For comparison, absolute humidity 0.03kg-H2O/kg-dry
When the filament bundle was treated in the same manner under an air atmosphere, the filament bundle was hardly opened.

Comparative Example 2 The same procedure as in Example 1 was carried out except that a nip roll made of silicone rubber was placed on the drive metal roll to press down the fiber bundle. In this case, although the fiber bundle was spread, the spread width was extremely narrow and the spreadability was poor.

Example 2 A polyarylate filament bundle of 500 dr/100 f was opened in the same manner as in Example 1, and a good opened state was obtained. However, in this case, it was necessary to increase the air flow rate slightly.

Example 3 A bundle of polyethylene terephthalate filaments of 1000 dr/192 f was heated to an absolute humidity of 0.0 using the apparatus shown in FIG.
Under an atmosphere of 15kg-H2O/kg-dryair, yarn processing speed 1500m/min, air flow rate 0.4Nm3
When a fiber opening test was conducted at /min, it was possible to stably open the fiber for a long time.

Example 4 When a 450 dr/150 f polybutylene terephthalate filament bundle was opened under the same conditions as in Example 1, it was found that it could be opened stably for a long period of time.

[0022]

According to the method of the present invention, various polyester multifilament bundles can be efficiently and stably opened into a monofilament shape. The obtained opened filament is propelled onto a collection device in the form of a wire mesh belt conveyor that moves continuously by an air stream emitted from an air gun to form a web, and then subjected to methods such as calendering, needle punching, and applying a binder. By forming appropriate entanglement and adhesion between the fibers, a uniform nonwoven fabric can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of a filament bundle opening device used in carrying out the present invention.

[Explanation of symbols]

1 Untwisted continuous multifilament supply bobbin 2 Untwisted continuous multifilament before opening 3 Tension adding device 4a Metal roll 4b Separate roll 5 Air gun 6 Compressed air inlet 7 Multifilament after opening

Claims (1)

[Claims] Claim 1: A non-twisted polyester multifilament bundle at an absolute humidity of 0.024 kg-H2O/kg-dr.
The material is passed through a metal Nelson roll in an atmosphere of less than y air without being twisted, and is triboelectrified by contact peeling with the metal roll, and then passed through an air gun injecting compressed air to open it into a monofilament shape. A method for opening a polyester multifilament bundle characterized by fibers.