JPH05272014A - Thermally fusible acrylic conjugate fiber - Google Patents

Abstract

PURPOSE:To obtain thermally fusible acrylic conjugate fiber remarkably improved in fiber physical properties such as mechanical strength. CONSTITUTION:The objective thermally fusible acrylic conjugate fiber comprises a thermally fusible acrylic polymer (A), containing <=80wt.% acrylonitrile and sandwiched between an acrylic polymer (B) and a part of the thermally fusible acrylic polymer (A) is exposed to the fiber surface at >=2 places in the fiber axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic composite fiber having excellent heat fusion properties and fiber properties.

[0002]

Prior Art Attempts to impart heat fusible properties to fibers are known prior to the filing of this application. For example, in Japanese Examined Patent Publication No. 54-47473, crystalline polypropylene (first component), ethylene vinyl acetate copolymer or a saponified product thereof and polyethylene (second component) are spun side-by-side or in a core-sheath type to perform interfiber spinning. A heat-adhesive conjugate fiber having improved heat-fusibility and heat-fusibility with other foreign materials is disclosed. However, although this fiber has good adhesiveness with fibers other than acrylic synthetic fibers, it has poor adhesiveness with acrylic synthetic fibers and cannot be dyed with a cationic dye for acrylic synthetic fibers. There were various problems. Further, it is difficult to melt-spin a polymer containing a large amount of acrylonitrile, and it has been difficult to industrially produce a heat-fusible acrylic conjugate fiber similar to the above by melt spinning.

Further, a polymer having a heat melting property of 80% by weight or less of acrylonitrile is known, but since such a polymer has poor heat resistance, when it is spun in the same process as a usual acrylic fiber, it is not manufactured. In addition, there was a problem that the heat treatment could not be performed sufficiently because of the adhesion due to heat, and the fiber physical properties such as mechanical strength were inferior.

The present inventors have completed the present invention as a result of earnest research to improve the above drawbacks.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat-fusible acrylic conjugate fiber in which fiber properties such as mechanical strength are greatly improved.

[0006]

In the heat-fusible acrylic conjugate fiber of the present invention, the heat-fusible acrylic polymer (A) containing 80% by weight or less of acrylonitrile is the acrylic polymer (B).
And a part of the heat-fusible acrylic polymer (A) is exposed on the fiber surface at two or more locations along the fiber axis direction.

In other words, in the acrylic conjugate fiber of the present invention, most of the fiber surface is covered with the acrylic polymer (B) having good heat resistance and good strength, and the heat-fusible acrylic polymer ( Part of A) is exposed at two or more locations along the fiber axis direction.

By covering most of the fiber surface with the acrylic polymer (B) having good heat resistance and strength, the fiber strength is maintained, and the fiber is prevented from sticking in the manufacturing process.

Further, a part of the heat-fusible acrylic polymer (A) is exposed at two or more locations along the fiber axis direction, so that the melted heat-fusible acrylic polymer (A) is pressed or the like. The fibers are squeezed out to the surface of the fiber corresponding to the change in volume due to the change in volume, and have sufficient heat fusion property. When the partial exposure of the heat-fusible acrylic polymer (A) is less than two locations,
Being protected by the acrylic polymer (B), it prevents the internally melted heat-fusible acrylic polymer (A) from being squeezed out on the fiber surface in response to a volume change due to pressure or the like. Therefore, it becomes impossible to exhibit sufficient heat fusion property.

In the present invention, the ratio of the heat-fusible acrylic polymer (A) to the acrylic polymer (B) is 1 part by weight of the heat-fusible acrylic polymer (A). (B) is 0.3 to 4 parts by weight, preferably 0.5 to 3 parts by weight. If the amount of the acrylic polymer (B) is less than 0.3 parts by weight, the surface coating is insufficient, resulting in poor fiber physical properties and large sticking during the manufacturing process. If the amount of (B) exceeds 4 parts by weight, the heat fusibility of the heat fusible acrylic polymer (A) will be insufficient.

In the present invention, the heat fusible acrylic polymer (A) exposed on the fiber surface has a total surface area of 2
-30%, preferably 4-15%. If the exposed surface area of the heat-fusible acrylic polymer (A) is less than 2%, the heat-fusion is insufficient, while if it exceeds 30%, the heat-fusible polymer (A) has a large portion. As a result, the physical properties of the fiber become poor,
Moreover, the stalemate in the manufacturing process becomes large.

Next, a production example of the fiber of the present invention will be described.

The heat-fusible acrylic polymer (A) in the present invention means an acrylic copolymer containing 80% by weight or less of acrylonitrile. Examples of the copolymerizable monomer include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl pyrmethacrylate,
Acrylic acid esters and methacrylic acid esters such as butyl methacrylate, vinyl compounds such as acrylamide, methacrylamide, vinyl acetate, styrene, vinyl chloride, vinylidene chloride, vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, p-styrene. Sulfonic acid,
One or two or more of 2-acrylamido-2-methylpropanesulfonic acid and salts thereof can be used in combination.

The content of the copolymerizable monomer of the heat-fusible acrylic polymer (A) is 20 to 60% by weight, preferably 25.
~ 50% by weight. When it is less than 20% by weight, the heat-fusible acrylic polymer (A) has a low heat-fusing property. On the other hand, when it is more than 60% by weight, sticking is large during the fiber manufacturing process, and the spinning operation is performed. Sex is also reduced.

On the other hand, as the acrylic polymer (B),
A known acrylic polymer having fiber-forming properties, that is, 3
0 wt% or more of acrylonitrile (hereinafter abbreviated as AN)
Modacrylic polymer containing 80% by weight or more of A
Examples thereof include acrylic polymers having N and copolymers thereof.

The heat-fusible acrylic polymer (A) and acrylic polymer (B) are dimethylformamide, dimethylacetamide, dimethylsulfoxide, etc., and alkali such as lithium rhodanide, potassium rhodanide, sodium rhodanide, etc., respectively. A spinning stock solution having a polymer concentration of 10 to 30% by weight is prepared by appropriately dissolving it in a solvent such as a metal rhodanate salt, rhodan ammonium, zinc chloride or perchloric acid.

This spinning dope is guided to, for example, a composite spinneret having the structure shown in FIG. 1 and discharged into a coagulating bath which serves as a coagulating agent for the aqueous solution of the organic solvent or inorganic solvent.

At that time, the polymer solution discharged from the spinneret may be directly introduced into the coagulation bath (wet spinning method),
Further, a spinneret is provided at a position of about 2 to 20 mm on the surface of the coagulation bath, and the spinning solution discharged from the spinneret hole is run through a minute space between the spinneret hole and the surface of the coagulation bath, and then coagulated. A so-called dry-wet spinning method of introducing into the bath may be used.
Further, the fiber of the present invention can also be obtained by an ordinary dry spinning method.

The coagulated yarn drawn out from the coagulation bath is subjected to treatments such as washing with water or drawing at the same time as washing, or drawing with water, or washing with water, or drawing after washing with water, and then densified to give mechanical crimping. Let The fiber thus obtained is used for heat fusion.

[0020]

The present invention will be described in more detail with reference to the following examples.

The strength and elongation in the examples are JIS L.
1015. In addition, the heat-fusible property was made into a non-woven fabric of 200 g / m ² from the obtained fiber and pressure-bonded at 140 ° C. for 5 minutes, and the result of “○”, “△”, and “×” was confirmed by a visual test by 10 expert inspectors. It was evaluated in three levels.

Examples 1 to 3 and Comparative Example 1 AN / methyl acrylate / 2-acrylamide-2-
A heat-fusible acrylic polymer (A) having a composition of sodium methylpropanesulfonate = 70/28/2 was dissolved in dimethylformamide (DMF) at a concentration of 23% by weight to prepare a spinning dope (a). .. On the other hand, an acrylic polymer (B) having a composition of AN / methyl acrylate / 2-acrylamido-2-methylpropanesulfonic acid sodium = 91/7/2 was similarly dissolved in DMF at 23% by weight to prepare a spinning dope ( B) was created.

The spinning stock solutions of the above two types (a) and (b) are shown in Table 1.
The mixture was guided to the composite spinneret having the distribution structure shown in FIG. 1 at the ratios described, and discharged into a coagulating liquid which was a 60% by weight DMF aqueous solution to prepare a coagulated yarn. Further, the spinning draft was 0.4, and the take-up speed of the solidified yarn was 10 m / min. 90 solidified yarns
It was stretched 3.5 times in hot water at 0 ° C, the drawn yarn was sufficiently washed with warm water, and after applying a primary oil agent, dried and densified at 100 ° C. Then, a secondary oil agent and a crimp were applied to obtain acrylic fibers having a denier of 3 and Examples 1 to 3 and Comparative Example 1 were used.
Got the product.

Comparative Examples 2 to 3 The heat fusible acrylic polymer (A) spinning stock solution (a) and the acrylic polymer (B) spinning stock solution (b) used in Examples 1 to 3 are shown in Table 1. The same processes as in Example 1 were carried out except that a normal side-by-side type composite spinneret was used at the ratios described, to obtain products of Comparative Examples 2-3.

Table 1 shows the compositions, cross-sectional views, strength and elongation, and heat fusion properties of Examples 1 to 3 and Comparative Examples 1 to 3.

[0026]

[Table 1]

As is clear from Table 1, the product of the example has excellent fiber characteristics and heat fusion property as compared with the product of the comparative example. In the case of Comparative Example 3, a sample could not be collected due to a large amount of sticking during the manufacturing process.

[0028]

EFFECTS OF THE INVENTION The heat-fusible acrylic conjugate fiber of the present invention has excellent fiber physical properties and excellent heat-fusability, and is dyed with a cationic dye in the same manner as ordinary acrylic synthetic fibers. Can be done. In addition, it shows good heat fusion property not only to acrylic synthetic fibers but also to other fiber materials, and can be used for non-woven fabrics, paper, filters, padding, etc. without a binder, which is extremely useful in industry. Is.

[Brief description of drawings]

FIG. 1 is an example of a composite spinneret.

2 is a cross-sectional view of the fiber of Example 1. FIG.

FIG. 3 is a cross-sectional view of the fiber of Example 2.

FIG. 4 is a cross-sectional view of the fiber of Example 3.

5 is a cross-sectional view of fibers of Comparative Example 1. FIG.

FIG. 6 is a cross-sectional view of fibers of Comparative Example 2.

FIG. 7 is a cross-sectional view of fibers of Comparative Example 3.

[Explanation of symbols]

 B Spinning stock solution containing a heat-fusible acrylic polymer b Spinning stock solution containing an acrylic polymer 1 Distribution plate 2 Distribution plate 3 Spacer space 4 Nozzles

Claims (1)

[Claims] 1. A heat-fusible acrylic polymer (A) containing 80% by weight or less of acrylonitrile is an acrylic polymer (B).
And a part of the heat-fusible acrylic polymer (A) is exposed on the fiber surface at two or more locations along the fiber axis direction. Composite fiber.