JP2909837B2 - Heat fusible fiber - Google Patents

Description

The present invention relates to a heat-fusible fiber. More specifically, it relates to a heat-fusible fiber having excellent nonwoven fabric processing properties and nonwoven fabric physical properties.

[Conventional technology and its problems] Nonwoven fabrics using heat-fusible fibers have high safety because they do not use a chemical binder such as an adhesive, and have good bulkiness and good texture. Is widely used as a skin agent for disposable sanitary supplies such as diapers, napkins and the like.

The heat-fusible fibers are classified into composite fibers and single-structure fibers according to their fiber structures.

The composite fiber is composed of two components, a low-melting resin and a high-melting resin, a parallel type in which two-component resins are arranged in parallel and a core-sheath type in which a high-melting resin is used as a core and a low-melting resin is used in a sheath. A structure has been proposed.

Polyethylene is often used as the low melting point resin, and polypropylene and polyester are often used as the high melting point resin.

The feature of this composite fiber is that the web is fixed by the low melting point resin, whereby a soft and bulky nonwoven fabric can be manufactured.

As the single component fiber, polypropylene and polyethylene fibers are mainly used. These fibers are inferior to composite fibers due to the bulkiness and flexibility of the nonwoven fabric, but are widely used because of their low cost.

However, the above-mentioned known heat-fusible fibers have the following problems.

The heat fusible fiber is manufactured into a nonwoven fabric by a hot embossing roll method and a hot air method using a suction dryer or the like. In both manufacturing methods, when the processing temperature of the nonwoven fabric is high, the strength of the nonwoven fabric is high, but the texture of the nonwoven fabric is poor,
Further, when the nonwoven fabric processing temperature is low, the strength of the nonwoven fabric is reduced, and there is a problem that the nonwoven fabric processing temperature must be strictly controlled.

As a solution to this problem, a fiber using a resin with a low melting point has been proposed to improve the low-temperature processability of the nonwoven fabric for both the conjugate fiber and the single-component fiber. However, the strength of the nonwoven fabric is not high and a sufficient effect has not been obtained.

In order to solve such problems of the conventional technology, the present inventors have conducted extensive research on heat-fusible fibers capable of producing a nonwoven fabric having a wide nonwoven fabric processing temperature range and a high nonwoven fabric strength in the production of a nonwoven fabric. The present invention is based on the finding that the above technical problems can be solved by producing a fiber using a resin composition in which a copolymer of propylene and butene-1 having a specific composition is mixed with a polyolefin resin as a resin component at a ratio within a certain range. Was completed.

[Means for Solving the Problems] The present invention has the following configuration (1) or (2).

(1) A heat-fusible fiber comprising a resin obtained by adding 5 to 100 parts by weight of a copolymer of propylene and butene-1 having a propylene content of 55 to 85 mol% based on 100 parts by weight of a polyolefin resin.

(2) high density or linear low density polyethylene resin,
A fiber composed of one or more resins selected from a polypropylene resin and a polybutene-1 resin is used as one component A of the conjugate fiber, and propylene and butene having a propylene content of 55 to 85 mol% with respect to 100 parts by weight of the polyolefin resin. A fiber comprising a resin to which 5 to 100 parts by weight of a copolymer of -1 is added is used as the other component B of the composite fiber,
A heat-fusible conjugate fiber for producing a nonwoven fabric, wherein all or a part of the components constitute the surface of the conjugate fiber.

The polyolefin resin used in the present invention includes low-density polyethylene, linear low-density polyethylene, high-density polyethylene or crystalline polypropylene, a copolymer of propylene and a small amount of ethylene such as an α-olefin, or a mixture thereof. .

The propylene / butene-1 copolymer having a propylene content of 55 to 85 mol% used in the present invention can be produced, for example, by the method described in JP-B-54-48845.

The copolymer of propylene and butene-1 used in the present invention must have a propylene content of 55 to 85 mol%. If the propylene content is less than 55 mol%, the stable productivity of the fiber will decrease, and if it exceeds 85 mol%, a sufficient effect cannot be obtained.

The blending amount of the copolymer of propylene and butene-1 used in the present invention is 5 to 100 parts by weight, preferably 10 to 70 parts by weight, based on 100 parts by weight of the polyolefin resin.

If the amount is less than 5 parts by weight, sufficient effects cannot be obtained, and if it exceeds 100 parts by weight, stable fiber production cannot be performed.

The heat-fusible fiber of the present invention has a light stabilizer, a nucleating agent, a lubricant,
Radical generators such as antistatic agents, pigments, peroxides,
A dispersing agent such as metal soap or a neutralizing agent can be used in combination as long as the object of the present invention is not impaired.

The raw material resin used for the heat-fusible fiber of the present invention is obtained by mixing a predetermined amount of the copolymer of propylene and butene-1 and the above-mentioned various compounds with the polyolefin in a usual mixing apparatus, for example, a Hensel mixer (trade name), Mix using a super mixer, ribbon blender, Banbury mixer, etc., and melt and knead with a usual single screw extruder, twin screw extruder, Brabender or roll, etc. at a temperature of 150 to 300 ° C., preferably 180 °
It can be obtained by melt-kneading pelletizing at ~ 250 ° C.

The heat-fusible fiber of the present invention may be prepared by using the above raw materials alone or as a raw material for one component of a side-by-side composite fiber, or preferably as a raw material for a sheath component of a core-in-sheath type composite fiber, using a generally known melt spinning method. And then stretched and crimped.

The raw material resin which can be preferably used as the core component of the composite fiber is not limited to the high-density polyethylene resin exemplified as the component A in the above (2), and known melt-spinnable raw material resins such as polyether, polyester, Polyester ether or polyamide can be used.

[Examples] Hereinafter, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited thereto. In addition, the measurement method or definition of the physical property value shown in the examples is collectively shown.

MFR (melt flow rate): According to the condition (L) of ASTM D1238.

MI (melt index): According to the condition (E) of ASTM D1238.

Non-woven fabric strength: A test piece having a length of 10 cm, a width of 5 cm, a length of 5 cm, and a width of 10 cm is cut out from a non-woven fabric having a basis weight of about 20 g / m ^{2 in} the machine direction, and the test piece is pulled using a tensile tester. The breaking strength of the nonwoven fabric in the machine direction (MD) and the machine direction (CD) was measured under the conditions of a speed of 100 mm / min and a test piece gripping interval of 5 cm, and was expressed in terms of a basis weight of 20 g of the nonwoven fabric.

Examples 1-4 Based on 100 parts by weight of high-density polyethylene (MI = 16), B
0.1 parts by weight of HT, 0.1 parts by weight of calcium stearate, propylene content of 74 mol%, propylene of MFR14 and butene-1 copolymer were put into a Hensel mixer at a ratio shown in Table 1 and mixed by stirring for 3 minutes. 40mm single screw extruder
Granulation was performed at 200 ° C. to obtain raw material pellets.

Using a core-sheath type composite fiber spinning machine with a nozzle diameter of 0.5 mm and 450 nozzles, polypropylene (MFR1
0) using the above raw material as a sheath component resin, and a spinning temperature of 280
A 9-denier core-sheath composite undrawn yarn was obtained at a temperature of 800 ° C. and a spinning speed of 800 m / min. Next, this undrawn yarn is drawn using a stable fiber manufacturing facility under the conditions of a drawing temperature of 100 ° C. and a draw ratio of 3 times, crimped, and then cut to obtain a 3 denier 50 mm long stable fiber. Was.

The stable fiber was formed into a web by a card machine having a winding speed of 7.5 m / min, and then a heated embossing roll was used to form an embossed area of 7%, a linear pressure of 11 kg / cm ² , and a roll speed of 3 m.
The web was point-bonded under the conditions of / min to obtain a nonwoven fabric.

 Table 1 shows the results of the strength of the nonwoven fabric.

In each case, a nonwoven fabric having excellent nonwoven fabric strength over a wide temperature range was obtained. Further, the texture of the nonwoven fabric was examined by touch, and all the nonwoven fabrics were soft.

Comparative Examples 1 to 3 The same procedures as in Examples 1 to 3 were carried out except that the propylene content was 75 mol% and the amount of the copolymer of propylene and butene-1 in MFR14 was 0, 4, and 105 parts by weight.

 Table 1 shows the results of the strength of the nonwoven fabric.

In Comparative Examples 1 and 2, when the embossing roll temperature is low, the strength of the nonwoven fabric is weak, and it can be seen that the nonwoven fabric processing temperature is narrower than in Examples 1 to 3. In Comparative Example 3, fibers were not obtained due to many yarn breaks and poor spinnability.

Examples 5 to 6 The amount of the propylene / butene-1 copolymer was set to 50 parts by weight, and the propylene content of this copolymer was as shown in Table 2 except that the propylene / butene-1 copolymer was used. Was carried out in the same manner as in Examples 1 to 3.

Table 2 shows the results of the strength of the nonwoven fabric. In each case, a nonwoven fabric having excellent nonwoven fabric strength over a wide temperature range was obtained. Further, the texture of the nonwoven fabric was examined by touch, and all the nonwoven fabrics were soft.

Comparative Examples 4-5 Examples 4-5 except that propylene and butene-1 copolymers having a propylene content of 50 mol% and 90 mol% were used.
Was performed in the same manner as described above.

 Table 2 shows the results of the strength of the nonwoven fabric.

In Comparative Example 4, the tow was wound around the drawing roll in the drawing step, and no fiber was obtained. Comparative Example 5 has a narrow nonwoven fabric processing temperature range and a low nonwoven fabric strength as compared with Examples 4 and 5.

Example 7 0.1 parts by weight of BHT, 0.1 parts by weight of calcium stearate and propylene content of 74 mol% based on 100 parts by weight of polypropylene of MFR10, propylene and butene-1 of MFR14
Was mixed in a Henssel mixer at a ratio shown in Table 3 and mixed with stirring for 3 minutes.
The mixture was melt-kneaded at 0 ° C and pelletized.

Using a spinning machine having a nozzle diameter of 0.5 mm and 450 nozzles, a 4-denier undrawn yarn was spun from the raw material at a spinning temperature of 280 ° C. and a spinning speed of 800 m / min. Next, this undrawn yarn is drawn at a drawing temperature using a stable fiber manufacturing facility.
The film was stretched under the conditions of 80 ° C. and a stretching ratio of 2 times, and after giving a scratch, it was cut to obtain a 2-denier stable fiber having a length of 50 mm.

After the stable fiber was formed into a web by a card machine having a winding speed of 7.5 m / min, the web was point-bonded by a heated embossing roll to form a nonwoven fabric.

 Table 3 shows the results of the nonwoven fabric strength.

Even with a single component fiber, a nonwoven fabric having a wide nonwoven fabric processing temperature range and high nonwoven fabric strength was obtained.

Comparative example 6 It carried out like Example 7 except not using a copolymer of propylene and butene-1.

 Table 3 shows the results of the nonwoven fabric strength.

It can be seen that the nonwoven fabric processing temperature range is narrower and the strength of the nonwoven fabric is lower than in Example 7.

[Results of the Invention] According to the present invention, the narrowness of the nonwoven fabric processing temperature condition width, which is a drawback of the conventional heat-fusible fiber, is improved, and a high-strength nonwoven fabric can be manufactured under a wide processing temperature condition.

As a result, the fiber of the present invention is suitable as a raw material of a nonwoven fabric suitable for various uses including paper diapers.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D01F 6/46 D01F 8/06 D04H 1/54

Claims (2)

(57) [Claims] (1) Propylene having a propylene content of 55 to 85% by mole based on 100 parts by weight of a polyolefin resin;
1. A heat-fusible fiber comprising a resin to which 5 to 100 parts by weight of a copolymer has been added. 2. A fiber comprising at least one resin selected from high-density or linear low-density polyethylene resin, polypropylene resin or polybutene-1 resin is used as one component A of the composite fiber, and 100 parts by weight of polyolefin resin is used. On the other hand, a fiber composed of a resin obtained by adding a copolymer of propylene and butene-1 having a propylene content of 55 to 85 mol% in an amount of 5 to 100 parts by weight is used as the other component B of the composite fiber,
A heat-fusible conjugate fiber for producing a nonwoven fabric, wherein all or a part of the component B constitutes the surface of the conjugate fiber.