JPH04241159A - Thermally bonded nonwoven fabric - Google Patents

Abstract

PURPOSE:To provide nonwoven fabric with flexibility and sliding friction resistance by using an ethylene copolymer as one component of conjugate yarn consisting of two components to give thermally bondable yarn and forming the yarn into thermally bondable nonwoven fabric. CONSTITUTION:An ethylene copolymer is used as a first component and a thermoplastic resin having 130-270 deg.C melting point as a second component to give thermally bondable conjugate yarn and the yarns are bonded by heat melting of the first component of the conjugate yarn to give nonwoven fabric. The nonwoven fabric is much more flexible than conventional thermally bondable nonwoven fabric and is suitable as a surface material of sanitary articles. Since the nonwoven fabric has large sliding friction resistance, carpets will not hardly moved when the nonwoven fabric is used for the under surface of various kinds of carpets.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a heat-adhesive nonwoven fabric, which has excellent heat-adhesive properties, especially with non-polyolefin fiber materials, and can be thermally bonded at a low temperature that does not exceed the melting point of polyethylene. The present invention relates to a thermally bonded nonwoven fabric with a soft and flexible feel.

0002

BACKGROUND OF THE INVENTION Most conventional heat-adhesive nonwoven fabrics include polyolefin-based heat-adhesive fibers. The polyolefin-based heat-adhesive fiber is, for example, a composite made of a combination of polypropylene and polyethylene, or a copolymer of polypropylene and ethylene, as described in Japanese Patent Publication No. 50-4767 and Japanese Patent Publication No. 55-17807. Fibers were basic.

[0003] Such polyolefin composite fibers are characterized in that they can be thermally bonded at a relatively low temperature (120°C), and that the resulting nonwoven fabric is softer and has a better texture than other nonwoven fabrics.

0004

[Problems to be Solved by the Invention] However, these nonwoven fabrics using polyolefin-based heat-adhesive fibers have low sliding friction resistance, so they tend to slip easily on smooth surfaces, and are used, for example, as linings on the bottom of various mats. In this case, there is an inconvenience that even a slight external force causes the device to move and change its position.

Composite fibers containing amorphous polyester as a thermal adhesive component have also been attempted (Japanese Patent Publication No. 4780/1983).
No. 6) Nonwoven fabrics made from polyester-based thermal adhesive components have the disadvantage of poor texture due to their flexibility.

The present invention provides a heat-adhesive nonwoven fabric formed by thermally fusing heat-adhesive conjugate fibers that maintains the low adhesion temperature and flexibility of polyolefins and has good adhesion to non-polyolefin fibers. be.

[0007]

[Means for Solving the Problems] The present inventors have discovered that a copolymer resin of ethylene carboxylic acid ester and ethylene has good adhesion to both polyolefin resins and non-polyolefin resins, and has a large sliding friction resistance. It was discovered that the material melts at a relatively low temperature, leading to the present invention.

That is, the present invention comprises 5 to 30% by weight of acrylic ester and/or methacrylic ester and 0 to 10% by weight of ethylene carboxylic acid selected from acrylic acid, methacrylic acid and maleic acid. The first component is an ethylene copolymer consisting of a total of 5 to 30% by weight of an ethylene carboxylic acid monomer and 95 to 70% by weight of ethylene, and the second component is a thermoplastic resin with a melting point (T° C.) of 130<T<270. It is characterized in that it is formed by thermally fusing two components, the first component of which occupies at least a portion of the fiber surface, of thermoadhesive conjugate fibers.

[0009] The first component serving as the thermal adhesive component of the composite fiber is a copolymer of ethylene and an ethylene carboxylic acid ester such as an acrylic ester or a methacrylic ester. The higher the proportion of ethylene carboxylic acid ester in the copolymer, the better the adhesion of the composite fiber will be, but if it exceeds 30% by weight, the copolymer will have lower hardness and stronger rubber properties. As a result, the surface of the composite fiber becomes soft, resulting in poor card passing properties and difficulty in forming a web. On the other hand, if it is less than 5% by weight, the adhesive strength will be insufficient, so the proportion of ethylene carboxylic acid ester in the copolymer should be 5 to 30% by weight,
Preferably it is 10 to 25% by weight.

The alcohol moiety of the ethylene carboxylic acid ester preferably has 1 to 5 carbon atoms, with methyl acrylate and ethyl acrylate being particularly preferred. In addition, if the ethylene copolymer is a terpolymer with ethylene carboxylic acid added as a monomer in addition to the above-mentioned ethylene and ethylene carboxylic acid ester, the surface of the resulting composite fiber will have strong rubbery properties. This makes the nonwoven fabric even more flexible.

However, if the amount of ethylene carboxylic acid is too large, adhesion between fibers will occur during melt spinning, so the amount should be 10% or less. Even in the case of such a terpolymer, the total amount of ethylene carboxylic acid ester and ethylene carboxylic acid is kept at 30% by weight or less to prevent the rubbery properties of the composite fiber from becoming excessive. The melting point of an ethylene copolymer with such a composition becomes lower as the amount of ethylene carboxylic acid monomer increases, and conversely, as the amount of ethylene increases, the melting point becomes higher, but the range is 70 to 130 ° C. .

The melting point of the second component of the composite fiber must be higher than the melting point of the ethylene copolymer of the first component and lower than the decomposition temperature of the first component. The melting point of the first component is 130
℃ or less, the decomposition temperature is 300℃. Therefore, the melting point (T°C) of the second component must be lower than 300°C,
From the stability of melt spinning, the range is 130<T<270. Thermoplastic resins with such melting points are selected from polypropylene, polyethylene terephthalate, polybutylene terephthalate, nylon-6, nylon-66 and nylon-12. Copolymers of these are also conveniently used. In particular, polypropylene, polyethylene terephthalate, and nylon-6 are preferably used for economical reasons, so the properties of each resin such as flexibility, elasticity, and hygroscopicity may be appropriately selected depending on the intended use.

The structure of the composite fiber is such that the first component occupies at least a portion, preferably 30% or more, of the fiber surface. The composite ratio of both components is the cross-sectional area ratio of the first component/second component.
The ingredients are within the range of 30/70 to 70/30,
It is preferable from the viewpoint of spinnability, strength, and adhesive strength of the composite fiber.

[0014] In order to produce such a composite fiber, the first step is to
The spinning temperature is set so that the MFR (melt fluorate, measured according to JIS K7210, weight: 2169 g) at the spinning temperature for both the component and the second component satisfies 15≦MFR<300. The first component exhibiting such melt fluidity has an MI (melt index) of 190°C and a weight of 2
When measuring at 169g, use one that satisfies 5<MI<200. The spinning temperature is 15°C or more higher than the melting point of the second component and lower than 300°C. After spinning, good fiber strength can be obtained by drawing the fiber twice or more at a temperature of 20° C. or higher and 15° C. lower than the melting point of the first component.

[0015] Some of the composite fibers applied to the present invention have large shrinkage at high temperatures (in Example 11 described later, 13
(40% dry heat shrinkage rate at 0°C).If shrinkage becomes a nuisance in practical use of such fibers, it is advisable to perform tension heat treatment at 80 to 100°C (at a temperature lower than the melting point of the ethylene copolymer).

[0016] Furthermore, the composite fibers applied to the present invention can be thermally bonded at relatively low temperatures, and the fibers to be bonded can be not only polyolefin fibers but also non-polyolefin fibers. In addition to fibers, it can also be bonded to various plastic molding materials, wood, and iron, and it has high sliding friction resistance and is highly flexible.

Furthermore, even if the content of ethylene carboxylic acid ester in the first component ethylene copolymer is increased to 30% by weight, it can be spun, which greatly improves the thermal adhesive strength of the resulting composite fiber. can be done.

[0018]

[Examples] [Examples 1 to 11] Ethylene copolymer as the first component, polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), nylon-6 (Ny-6) as the second component ,
Using nylon-66 (Ny-66) and ethylene propylene random copolymer (EP), the composite ratio was adjusted to 4 for the first component.
Sheath-core type (S/C) and parallel type (S/S) composite fibers were spun at a ratio of 0:60 of the second component. Next, this was divided into two parts, one of which was drawn in hot water at 60°C, crimped using a stuffer box, dried, and then cut to obtain staple fibers with a fiber length of 51 mm. In addition, the other one was stretched in hot water at 60°C and immediately cut to a fiber length of 5 mm.
It was made into short cut fibers.

For comparison, a sheath-core type composite fiber was produced in the same manner using ethylene vinyl acetate copolymer as the sheath component and polypropylene as the core component. The proportion of vinyl acetate as a sheath component in the copolymer was 6%. Next, nonwoven fabric and paper were obtained using the above fibers. The non-woven fabric is a blend of 30% staple fiber of the present invention and 2 denier, 51 mm polyester fiber, made into a web using a roller card, and then heated at 120°C.
Process the web by sandwiching it between nets using a hot air penetrating type thermal processing machine.
The thermal adhesive component of the composite fibers was melted and the fibers were bonded together to form a nonwoven fabric with a basis weight of 40 g/m2.

Paper is made by cutting the above heat-adhesive fibers into 5 mm pieces, mixing 20% of the short cut fibers with rayon having a thickness of 2 deniers and a length of 5 mm, and drying the paper at 120° C. The paper weight was 20 g/m2.

Table 1 shows the various performances of each fiber of the above examples and comparative examples, and Tables 2 and 3 show the tearing lengths (km) of the nonwoven fabric and paper.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025] The tearing length of the above-mentioned nonwoven fabric and paper is 50 m in width.
The breaking strength of a sample with a length of 100 mm and a tensile speed of 300 m/min was measured and calculated using the following formula. Regarding the texture, those that were softer than the comparative example were rated ○.

[0026]

[Formula 1]

[Examples 12 to 15, Comparative Examples 2 to 4] First
Ethylene copolymer as a component, 270°C as a second component
A sheath/core type (S/C) composite fiber was spun using heat-reducible polypropylene having an MFR of 13 g/10 min at a weight ratio of 55 for the first component and 45 for the second component. Next, this was stretched in hot water at 60°C, and the same procedure as in Example 1 was carried out to obtain 2.
．． It was made into a staple fiber of 3 denier x 51 mm.

As comparative examples, 2 denier x 51 mm and 4 denier x 5 mm [NBF (S
H), manufactured by Daiwabo Co., Ltd.], 2 denier x 51 with polypropylene as the core component and high-density polyethylene as the sheath component
mm [NBF (H) manufactured by Daiwabo Co., Ltd.] was made into a web using a roller card, and then processed by sandwiching the web between nets using a hot air penetration type thermal processing machine to melt the thermal adhesive component of the composite fiber and create a bond between the fibers. were adhered to form a heat-adhesive nonwoven fabric with a basis weight of 40 g/m2. The evaluation results of Examples 12 to 15 and Comparative Examples 2 to 4 are shown in Table 4.

[0029]

[Table 4]

Regarding the feel of the nonwoven fabric, those that were softer than the nonwoven fabrics of Comparative Examples 2 and 3 of the same denier were rated ○. In addition, the sliding friction resistance of the nonwoven fabric was measured as follows.

A 10 cm square piece of non-woven fabric is placed on a mirror-finished plate glass, a 13 g 5 cm x 5 cm aluminum plate is placed in the center of the non-woven fabric, and weights each weighing 50 g, 100 g, and 200 g are placed on top of the non-woven fabric under the respective measurement conditions. Place according to the
A clip was attached to the end of the nonwoven fabric in the longitudinal direction of the aluminum plate, the clip was gently pulled using a hand-type spring balance, and the balanced tensile tension was measured in g for evaluation.

The nonwoven fabrics of Examples 12 to 15 were significantly less slippery than conventional nonwoven fabrics.

[0033]

Effects of the Invention As described above, the heat-adhesive nonwoven fabric of the present invention contains 5 to 30% by weight of acrylic ester and/or methacrylic ester and ethylene carboxylic acid selected from acrylic acid, methacrylic acid, and maleic acid. The first component is an ethylene copolymer consisting of an ethylene carboxylic acid monomer of 0 to 10% by weight and a total of 5 to 30% by weight, and 95 to 70% by weight of ethylene, and the melting point (T ° C.) is 130<
The second component is a thermoplastic resin with T<270, and the first component contains 10% by weight or more of thermally bondable composite fibers that occupy at least a portion of the fiber surface, and is bonded by thermal melting of the first component. In particular, the above-mentioned ethylene copolymer feels extremely soft to the touch, and even when the fiber is thicker than conventional polyolefin heat-adhesive fibers, it feels soft to the touch.

[0034] Therefore, it is suitable as a surface material sheet for napkins and paper diapers, and is particularly useful as a surface material for paper diapers for soft stools.

Furthermore, since it has a non-slip characteristic, it is suitable for use as a backing for rugs such as entrance mats, carpets, bath mats, etc., or as underlays and underlays for various ornaments. When applied to such uses,
It is preferable to form a nonwoven fabric in which heat-adhesive conjugate fibers containing the above-mentioned ethylene copolymer as a first component are concentrated on the floor surface side. Furthermore, since the thermal bonding temperature is relatively low, the nonwoven fabric can be bonded to other articles using a heat source such as a hair dryer or a soldering iron, making it convenient to handle.

Claims (1)

[Claims] Claim 1: 5 to 30% by weight of acrylic ester and/or methacrylic ester, 0 to 10% by weight of ethylene carboxylic acid selected from acrylic acid, methacrylic acid, and maleic acid, and the total amount of these is 5 to 30% by weight. ~30% by weight
of ethylene carboxylic acid monomer and ethylene 95-7
The first component is an ethylene copolymer consisting of 0% by weight, the second component is a thermoplastic resin with a melting point (T ° C.) of 130 A heat-adhesive nonwoven fabric containing 10% by weight or more of heat-adhesive conjugate fibers and bonded by thermal melting of the first component.