JPH0418121A - Hot-melt fiber - Google Patents

Abstract

PURPOSE:To provide the subject fiber composed of a resin produced by adding a polyolefin resin and a specific propylene/butene-1 copolymer at specific ratios, having excellent processability to form a nonwoven fabric and useful for sanitary goods, etc. CONSTITUTION:The objective fiber is composed of a resin produced by adding 5-100 pts.wt. (preferably 10-70 pts.wt.) of a propylene/butene-1 copolymer having a propylene content of 55-85mol% to 100 pts.wt. of a polyolefin resin (e.g. low- density polyethylene). A hot-melt conjugate fiber giving a nonwoven fabric having excellent physical properties can be produced by using the above fiber as the sheath component and a high-density polyethylene, etc., as the core component.

Description

[Detailed description of the invention] [! Field of Industrial Application] The present invention relates to heat-fusible fibers. More specifically, the present invention relates to heat-fusible fibers with excellent nonwoven processability and nonwoven physical properties.

[Conventional technology and its problems] Nonwoven fabrics using heat-fusible fibers are highly safe because they do not use chemical binders such as adhesives, and the bulkiness of nonwoven fabrics makes them easy to use. It is widely used as a skin agent for disposable hygiene products such as disposable diapers and napkins.

Heat-fusible fibers are the best! Based on the IN structure, fibers can be divided into composite fibers and single-structure fibers.

The composite MIN consists of two components, a low melting point resin and a high melting point resin, and includes a parallel type in which the two component resins are arranged in parallel, and a core-sheath type in which the high melting point resin is the core and the low melting point resin is in the sheath. structure is proposed.

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

A feature of this composite fiber is that the web is fixed by a low-melting point resin, which makes it possible to produce a flexible and bulky nonwoven fabric.

As single component fibers, polypropylene and polyethylene fibers are mainstream. Although this fiber is inferior to composite fibers in bulk and flexibility of nonwoven fabrics, it is widely used because of its low price.

However, the above 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, if the nonwoven fabric processing temperature is high, the nonwoven fabric strength will be high, but the texture of the nonwoven fabric will be poor, and if the nonwoven fabric processing temperature is low, the nonwoven fabric strength will be low, so the nonwoven fabric processing temperature must be strictly controlled. This problem was found.

As a solution to this problem, composite fibers, single component *I!
In order to improve the low-temperature processability of non-woven fabrics, fibers using resins with a low melting point have been proposed, but in this case, low-temperature processing of non-woven fabrics is possible, but the strength of the non-woven fabric is not high and sufficient effects cannot be obtained. do not have.

In order to solve the problems of the conventional technology, the present inventors conducted extensive research on heat-fusible fibers that can be processed in a wide range of non-woven fabric processing temperatures and can produce non-woven fabrics with high strength. The present invention was based on the finding that the above technical problem can be solved by producing fibers using a resin composition in which a polyolefin resin is mixed with a copolymer of propylene and butene-1 having a specific composition at a ratio within a certain range. completed.

[Means to solve the question] The present invention has the following configuration (1) or (2).

(1) Propylene and butene with a propylene content of 55 to 85 mol% based on 100 parts by weight of polyolefin resin.
A heat-fusible fiber made of a resin to which 5 to 100 parts by weight of copolymer No. 1 is added.

(2) High-density or linear low-density polyethylene resin,
One component A of the composite fiber is a fiber made of one or more resins selected from polypropylene resin or polybutene-1 resin, and propylene and butene with a propylene content of 55 to 85 mol% based on 100 parts by weight of polyolefin resin. The other component B of the composite fiber is a fiber made of a resin to which 5 to 100 parts by weight of the copolymer of -1 is added, and all or part of the component B constitutes the surface of the composite fiber. Adhesive composite 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 α-olefin such as ethylene, or a mixture thereof. .

The copolymer of propylene and butene-1 having a propylene content of 55 to 85 mol % used in the present invention can be produced, for example, by the method described in Japanese Patent Publication No. 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 fibers will decrease, and If it exceeds 85 mol%, sufficient effects cannot be obtained.

The 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, a sufficient effect will not be obtained, and if it exceeds 100 parts by weight, stable production of fibers will not be possible.

The heat-fusible fibers of the present invention contain light stabilizers, nucleating agents, lubricants, antistatic agents, pigments, radical generators such as peroxides, and dispersants or neutralizing agents such as metal soaps for the purpose of the present invention. They can be used together as long as they do not impair the properties.

The raw material resin used for the heat-fusible fiber of the present invention is prepared by mixing the polyolefin, a copolymer of propylene and butene-1, and predetermined amounts of the various compounds described above using a conventional mixing device such as a Hensel mixer (trade name), a super Mix using a mixer, ribbon blender, Banbury mixer, etc.
Melt-kneading temperature 150-300℃, preferably 1
It can be obtained by melt-kneading and pelletizing at 80°C to 250°C.

The heat-fusible fiber of the present invention can be produced by using the above-mentioned raw materials alone or as a raw material for one component of a parallel type conjugate fiber, or preferably as a raw material for a sheath component of a core-sheath type conjugate fiber, using a commonly known melt spinning method. After spinning, it is stretched and crimped before being manufactured.

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

[Examples] The present invention will be specifically explained below based on Examples and Comparative Examples, but the present invention is not limited thereto.
The measurement methods or definitions of the physical property values shown in the Examples will be summarized below.

MFR (melt flow rate): ^ According to condition (L) of S-cho M 01238.

Ml (melt index): ^ According to condition (E) of STM 01238.

Non-woven fabric strong fabric weight is determined by cutting out a test piece with a length of 10 cm and a width of 5 cm in the machine direction, and a length of 5 cm and a width of 10 cm from a non-woven fabric with a weight of 20 g/2. The tensile speed was 100mm/inch, and the specimen gripping interval was 5c.
- The breaking strength of the nonwoven fabric in the machine direction (MO) and machine direction and perpendicular direction (CD) was measured under the conditions of
Expressed in terms of 0g.

Examples 1 to 4 Based on 100 parts by weight of high-density polyethylene (MI-16), 0.1 part by weight of BIT, 0.1 part by weight of calcium stearate, 74 mol% propylene content, propylene and butene with MFR 14. 1 copolymer was put into a Hensel mixer in the ratio shown in Table 1, stirred and mixed for 3 minutes, and then granulated at 200° C. with a single-screw extruder having a diameter of 40 mm to obtain raw material pellets.

Using a core-sheath type composite fiber spinning machine with a nozzle diameter of 0.5 mm and a number of nozzles of 450, polypropylene (MFRIO) is used as the core component resin and the above raw material is used as the sheath component resin,
A core-sheath type composite undrawn yarn of 9 denier was obtained under the conditions of a spinning temperature of 280° C. and a spinning speed of 800 μ/sin.

Next, this undrawn yarn was stretched using stable fiber manufacturing equipment at a stretching temperature of 100°C and a stretching ratio of 3 times, crimped, and then cut to produce a stable fiber with a length of 3 denier and 50 m. Obtained.

Winding speed of this stable fiber is 7.5m/w
After forming into a web using an in-line card machine, the embossing point area is 7% and the linear pressure is 11 kg/c■2 using a heated embossing roll.
The web was point-bonded to obtain a nonwoven fabric at a roll speed of 3 mm/inch.

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

In all cases, nonwoven fabrics with excellent nonwoven fabric strength over a wide temperature range were obtained. In addition, the texture of the nonwoven fabrics was examined by touch, and all nonwoven fabrics were found to be flexible.

Comparative Examples 1 to 3 Examples 1 to 3 were carried out in the same manner as in Examples 1 to 3, except that the amount of the copolymer of propylene and butene-1 having a propylene content of 75 mol% and an MFR of 14 was 0.4.105 parts by weight.

Table 1 shows the results of the strength of the nonwoven fabric. It can be seen that in Comparative Example 1.2, when the embossing roll temperature is low, the strength of the nonwoven fabric becomes weaker, and the processing temperature of the nonwoven fabric is narrower than in Examples 1 to 3. In Comparative Example 3, fibers could not be obtained due to many yarn breakages and poor spinnability.

Examples 5 to 6 Except for using a copolymer of propylene and butene-1 in which the amount of propylene-butene-1 copolymer added was 50 parts by weight, and the propylene content of this copolymer was shown in Table 2. It was carried out in the same manner as Examples 1-3.

The results of the nonwoven fabric strength are shown in Table 2. In all cases, nonwoven fabrics with excellent nonwoven fabric strength over a wide temperature range were obtained. Also,
The texture of the nonwoven fabrics was examined by touch, and all nonwoven fabrics were found to be flexible.

Comparative Examples 4 to 5 Examples 4 to 5 except that propylene and butene-1 copolymers with propylene contents of 50 mol% and 90 mol% were used.
It was carried out in the same manner as in 5.

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

In Comparative Example 4, the tow stuck to the drawing roll during the drawing process and no fibers were obtained. It can be seen that Comparative Example 5 has a narrower nonwoven fabric processing temperature range and lower nonwoven fabric strength than Examples 4 and 5.

Example 6 and Comparative Example 6 With respect to 100 parts by weight of polypropylene of MFRIG, B
IT 0.1 part by weight, calcium stearate 0.1
Part by weight and propylene content 74 mol%, MFR14
The copolymers of propylene and butene ~1 in the proportions shown in Table 3 were put into a Hensel mixer, stirred and mixed for 3 minutes, and then melt-kneaded and pelletized at 200°C using a single-screw extruder with a diameter of 40 m+n.

Using a spinning machine with a nozzle diameter of 0.5+am and 450 nozzles, the raw material was spun at a spinning temperature of 280°C and a spinning speed of 8.
6 Next, the undrawn yarn of 4 denier was spun under the conditions of 00m+/mjn. Next, the undrawn yarn was stretched using stable fiber manufacturing equipment at a stretching temperature of 80°C and a stretching ratio of 2 times, and crimping was performed. Cut after giving 2 denier length SO+a
m stable fibers were obtained.

Winding speed of this stable fiber is 7.5■/■
After forming a web using an in-line card machine, the web was point-bonded using a heated embossing roll to form a nonwoven fabric.

Table 3 shows the results of the strength of the nonwoven fabric.

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

Comparative Example 6 The same procedure as Example 6 was carried out except that the copolymer of propylene and butene-1 was not used.

Table 3 shows the results of the strength of the nonwoven fabric.

It can be seen that the nonwoven fabric processing temperature range is narrower and the nonwoven fabric strength is lower than in Example 6.

[Effects of the Invention] According to the present invention, the narrow range of processing temperature conditions for nonwoven fabrics, which is a drawback of conventional heat-fusible fibers, is improved, and a highly strong nonwoven fabric can be produced under a wide range of processing temperature conditions.

As a result, the fibers of the present invention are suitable as raw materials for nonwoven fabrics used in various applications including disposable diapers.

that's all

Claims (2)

[Claims] (1) Propylene and butene with a propylene content of 55 to 85 mol% based on 100 parts by weight of polyolefin resin.
A heat-fusible fiber made of a resin to which 5 to 100 parts by weight of copolymer No. 1 is added. (2) High-density or linear low-density polyethylene resin,
One component A of the composite fiber is a fiber made of one or more resins selected from polypropylene resin or polybutene-1 resin, and propylene and butene with a propylene content of 55 to 35 mol% based on 100 parts by weight of polyolefin resin. - A fiber made of a resin to which 5 to 100 parts by weight of the copolymer of 1 is added is the other component B of the composite woven fiber, and all or part of the component B constitutes the surface of the composite fiber. Fusible composite fiber.