JPH0473215A - Hot-melt conjugate fiber having persistently hydrophilic property - Google Patents

Abstract

PURPOSE:To provide the subject fiber excellent in persistently hydrophilic prop erty composed of a thermoplastic polymer and a polymer blend of a polyolefin and a specific hydrophilic polyolefin, having sheath-core structure and useful for baby diaper, etc. CONSTITUTION:The objective fiber is composed of (A) a sheath component consisting of a polymer blend of (i) 98-40 wt.% of a polyolefin and (ii) 2-60 wt.% of a hydrophilic polyolefin which is an ethylene copolymer containing 20-95 wt.% of ethylene unit and 80-5 wt.% of one or more kinds of polyalkylene glycol (meth)acrylate units of formula (R1 and R2 and H or methyl; 1<=n<=9) and exhibiting a contact angle of <=80 deg. with water in the form of film and (B) a core component consisting of a thermoplastic polymer having a melting point of >= 150 deg.C. The ratio of the component A to the component to B is 20:80 - 80:20.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat-fusible conjugate fiber having durable hydrophilic properties.

(Prior Art) Heat-adhesive fibers for producing nonwoven fabrics and the like by interfiber thermal adhesion are known. For example, composite fibers with polypropylene and polyethylene as an adhesive component, composite fibers with polypropylene and copolymerized nylon as an adhesive component, composite fibers with polyethylene terephthalate and polyethylene as an adhesive component, and ethylene-polyvinyl alcohol copolymers. There is a composite fiber with polyethylene terephthalate as an adhesive component.

Recently, the field of sanitary materials such as baby diapers, diaper liners, and sanitary products, non-hygienic materials such as counter cloths for the restaurant industry, drainage bags for kitchen utensil sinks, base fabrics and fixing sheets for medical supplies, and surgical gowns for hospitals. , Nonwoven fabrics using interfiber thermal bonding fibers are widely used in the medical field, such as masks. Among these many nonwoven fabric products, especially those such as baby diapers and sanitary products are required to have hydrophilic properties that are more durable than conventional products. However, most of the conventionally commercially available products have been processed using a post-processing method in which the surface is treated with an oil agent or the like.

(Problems to be Solved by the Invention) However, in many cases where post-processing methods of surface treatment with oil or the like have good initial performance, the oil on the surface falls off after a certain amount of use, resulting in an extremely poor performance. Among these, in particular, wet-type nonwoven fabric applications such as surface materials for diapers and sanitary bats always go through a papermaking process during the manufacturing process. The hydrophilicity of both dry and wet nonwoven fabrics does not decrease even after washing with cold or warm water. There is a need to develop fibers for thermal bonding that are extremely durable and hydrophilic.

(Means and effects for solving the problem) In view of the above circumstances, the inventors of the present invention have made extensive studies, and as a result, the present inventors have developed a thermoplastic polymer having a melting point of 150°C or higher, using a blend polymer of polyolefin and hydrophilic polyolefin as a sheath component. It was discovered that a heat-fusible conjugate fiber containing as a core component has durable hydrophilicity, and the present invention was achieved based on this discovery.

The gist of the present invention is that the sheath component is a polyolefin fiber made of a blend polymer of 98 to 40% by weight of polyolefin and 2 to 60% by weight of hydrophilic polyolefin, and the melting point is 15%.
The hydrophilic polyolefin, which is a heat-fusible composite fiber whose core component is a thermoplastic polymer having a temperature of 0°C or higher and whose ratio of sheath component to core component is 20=80 to 80:20, has an ethylene unit (A). Contains 20 to 95% by weight, 80 to 5% by weight of one or more polyalkylene glycol (meth)acrylate units (B) represented by the following formula, and has a contact angle with water of 80° or less in a film state. Examples include ethylene copolymers.

R C'''CR2 HC00+CH2CHO+nH (R,,R: hydrogen or methyl group, 1≦n≦9) The sheath component of the present invention consists of a blend polymer of 98 to 40% by weight of polyolefin and 2 to 60% by weight of ethylene copolymer. .

If the ethylene copolymer content is less than 2% by weight, the heat-fusible composite fiber will not exhibit sufficient hydrophilicity. If the ethylene copolymer content exceeds 60% by weight, it becomes difficult to form fibers.

Examples of the polyolefin that is a component of the sheath component of the present invention include polyethylene, polypropylene, poly-3-methylbutene-1, poly-4-methylpentene-1, and the like.

In the ethylene copolymer which is another component of the sheath component of the present invention, the value of the polyalkylene glycol (meth)acrylate unit (A) is in the range of 1 to 9. If n exceeds 9, it is difficult to react uniformly with the ethylene unit (B), making it difficult to produce a polymer.

In this ethylene copolymer, the ratio of component A is 80 to 5
%.

If the content of component A is less than 5% by weight, the obtained heat-fusible conjugate fiber will not exhibit sufficient hydrophilicity, while if it exceeds 80% by weight, a large amount of ultra-low molecular weight will be produced, and polyolefin The ethylene copolymer is eluted into water from the heat-fusible composite fiber obtained by blending with the ethylene copolymer, and the durable hydrophilicity is lost.

This ethylene copolymer basically consists of two components, A and B, but other components may be included in addition to these components. Examples of such a third component include ethylenically unsaturated monomer units C such as ethylenically unsaturated vinyl esters and ethylenically unsaturated carboxylic acids.

As the sheath component of the present invention, a thermoplastic polymer having a melting point of 150°C or higher is used, examples of which include polyethylene terephthalate, polybutylene terephthalate, nylon-
6, nylon 6.6, polypropylene, etc.

By carrying out core-sheath type composite spinning using the above polymer and stretching, the heat-adhesive composite fiber of the present invention having durable hydrophilic properties can be obtained. The composite ratio of the sheath component and core component is 20:
It is necessary to make it 80-80:20 volume %. Sheath component is 2
If it is less than 0% by volume, thermal adhesion becomes insufficient, which is not preferable.

Moreover, if the sheath component exceeds 80% by volume, the shape stability of the adhesive fiber after thermal bonding will be lost, which is not preferable.

The fibers of the present invention can also be used as fusion-treated fiber aggregates consisting only of composite fibers of a blend polymer of polyolefin and hydrophilic polyolefin and other polymers, but they can be mixed with other fibers containing 10% by weight or more of the fibers. It is also used as a treated fiber aggregate.

As a fiber aggregate, especially one cut into 20 to 100 mm, it can be used as a dry nonwoven fabric binder, and also in 3 to 10 mm.
The cut material is suitable as a wet nonwoven fabric binder, and a nonwoven fabric with high strength and durable hydrophilic properties can be obtained.

(Example) The present invention will be described in detail using Examples below. Durable hydrophilicity as referred to in the present invention is evaluated using two methods: water permeability and water permeability, by making a prototype of handmade paper. It was carried out by Water permeability was determined by dropping one drop of water onto a prototype handmade paper using a burette, and determining with the naked eye the time it took for the water droplets that fell on the paper to be absorbed and for the paper to lose its luster when exposed to light.

In addition, regarding water permeability, a prototype handmade paper was placed on Kotsuton linter pulp, one drop of water was dropped using a burette, and the time until the water droplets on the paper no longer aggregated was measured with the naked eye. .

For durability, use test paper according to JIS L-0217-
Washing was repeated 10 times according to the No. 103 method, and performance was evaluated by measuring water permeability and water permeability after 10 times.

In practice, ethylene is composed of 42% by weight of polyethylene glycol methacrylate units whose average degree of polymerization is 8 and 58% by weight of ethylene units, and whose intrinsic viscosity [η] in xylene at 75°C is 0.15 dl/g. The copolymer and high-density polyethylene (Mitsubishi Polyethylene JX-10 manufactured by Mitsubishi Yuka Co., Ltd.) with a density of 0.958 g/cff13 were blended at a ratio of 12:88 (wt%) and melt-kneaded in a melt extruder. The pellets were pelletized and vacuum dried at 80° C. for 12 hours.

Next, this polymer was used as a sheath, and polyethylene terephthalate with [η] 0.64 was used as a core, and the core/sheath = 50150.
Core-sheath composite spinning with the cross section shown in the figure was carried out at the volume ratio. Spinning temperature 2
Extrude at 90℃ and roll up with 750InIn/1llin.

The obtained undrawn yarn was drawn to a drawing ratio of 3.2 times using a stable drawing machine and cut into 3 mm pieces. The obtained fiber had a single fiber fineness of 3.2 denier and a tensile strength of 3.95.
g/d, and tensile elongation was 32.6%.

80% drawn yarn, single fiber fineness 2.5 denier, fiber length 3
After mixing 20% by weight of the polyethylene terephthalate fibers of 100% by weight, the mixture was mixed and made using a square tabby paper machine to produce fiber paper.

Then, 1
Dry at 40℃ for 1 minute and adhere to a fabric weight of 50 g/ctn.
'I created a handmade paper.

Subsequently, hydrophilicity was evaluated, and the results shown in Table 1 were obtained, indicating that it had durable hydrophilicity.

Disaster Cause I Consists of 53% by weight of hydroxyethyl methacrylate units and has an intrinsic viscosity [η] of 0.21 dl in xylene at 75°C.
/g of ethylene copolymer and density of 0958 g/cm
3 high-density polyethylene (manufactured by Mitsubishi Yuka Co., Ltd., Mitsubishi Polyethylene JX-10) at a ratio of 10 = 90 (wt%) and melt-kneaded in a melt extruder to pelletize,
It was vacuum dried at 80°C for 12 hours.

Next, using this polymer as a sheath and elongating polyethylene terephthalate with [η] 0.64, the core/sheath = 50150.
Core-sheath composite spinning with the cross section shown in the figure was carried out at the volume ratio. Spinning temperature 2
It was extruded at 90°C and wound up at 750 m/mtn.

The obtained undrawn yarn was drawn under the same conditions as in Example 1. The obtained fiber had a single fiber fineness of 3. It had a tensile strength of 1 denier, a tensile strength of 4.02 g/d, and a tensile elongation of 33°8%.

80% by weight of the drawn yarn and 20% by weight of polyethylene terephthalate fibers having a single fiber fineness of 2.5 denier and a fiber length of 3mm.
After mixing, in the same manner as in Example 1, the basis weight was 50g/
I made handmade paper of ca+2.

Subsequently, hydrophilicity was evaluated, and the results shown in Table 1 were obtained, indicating that it had durable hydrophilicity.

Example 11 J - Ethylene copolymer consisting of 41% by weight of hydroxyethyl methacrylate units and 59% by weight of ethylene units and having an intrinsic viscosity [η] of 0.21 dl/g in xylene at 75°C and a density of 0. 958g7'cm3 of high-density polyethylene (Mitsubishi Polyethylene JX-10, manufactured by Mitsubishi Yuka Co., Ltd.) was blended at a ratio of 12:88 (wt%), melt-kneaded using a melt extruder, and pelletized at 80°. It was vacuum dried at C for 12 hours.

Next, this polymer was used as a sheath, and polyethylene terephthalate with [η] 0.64 was used as a core to form core/sheath-5015.
Core-sheath composite spinning of the cross section shown in the figure was performed at a volume ratio of 0. It was extruded at a spinning temperature of 290°C and wound up at a speed of 750 m/min. The obtained undrawn yarn was drawn under the same conditions as in Example 1.

The obtained fiber had a single fiber fineness of 3.2 denier, a tensile strength of 4.15 g/d, and a tensile elongation of 35.9%.

After mixing 80% by weight of the drawn yarn with 20% by weight of polyethylene terephthalate fibers having a single fiber fineness of 2.5 denier and a fiber length of 3 mm, the fabric weight was 5 og/min under the same conditions as in Example I.
I made handmade paper for air.

Subsequently, hydrophilicity was evaluated, and the results shown in Table 1 were obtained, indicating that it had durable hydrophilicity.

Comparative historical density 0. The sheath is made of 958 g/cm3 high-density polyethylene (Mitsubishi Polyethylene JX-10, manufactured by Mitsubishi Yuka Co., Ltd.),
Using polyethylene terephthalate with [η) of 0.64 as a core, core-sheath composite spinning with the cross section shown in the figure was performed at a core/sheath volume ratio of 50,150. Extruded at a spinning temperature of 290℃, 750m/
It was wound up with n+in.

The obtained undrawn yarn was drawn under the same conditions as in Example 1.

The obtained fiber had a single fiber fineness of 3.2 denier, a tensile strength of 4.43 g/d, and a tensile elongation of 34.8%.

20 polyethylene terephthalate fibers with 80% by weight of the drawn yarn, a single fiber fineness of 2.5 denier, and a fiber length of 3IIIl.
After mixing the weight percentages, handmade paper with a basis weight of 50 g/cm2 was prepared in the same manner as in Example 1.

Subsequently, hydrophilicity was evaluated, and the results shown in Table 1 were obtained, indicating that it did not have durable hydrophilicity.

Squeezability L An ethylene copolymer consisting of 85% by weight of hydroxyethyl methacrylate units and 15% by weight of ethylene units, with an intrinsic viscosity [η] of 0.22 dl/g in xylene at 75°C, and a density of 0. 958 g/cmff of high-density polyethylene (manufactured by Mitsubishi Yuka Co., Ltd., Mitsubishi Polyethylene JX-10) was blended at a ratio of 10:90 (wt%) and melt-kneaded in a melt extruder to pelletize. It was vacuum dried at ℃ for 12 hours.

Next, with this polymer as a sheath and polyethylene terephthalate with [η] 0.64 as a core, core/sheath = 5015.
Core-sheath composite spinning of the cross section shown in the figure was performed at a volume ratio of 0. It was extruded at a spinning temperature of 290°C and wound at 750n/alin.

The obtained undrawn yarn was drawn under the same conditions as in Example 1.

The obtained fiber had a single fiber fineness of 3.3 denier, a tensile strength of 3.67 g/d, and a tensile elongation of 36.7%.

After mixing 80% by weight of the drawn yarn with 20% by weight of polyethylene terephthalate fibers having a single fiber fineness of 2.5 denier and a fiber length of 3 mm, the fabric weight was 50 g/c in the same manner as in Example 1.
I created a handmade paper.

Subsequently, hydrophilicity was evaluated, and the results shown in Table 1 were obtained, indicating that although it had initial hydrophilicity, it did not have durable hydrophilicity.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, a blend polymer of a polyolefin and a specific hydrophilic polyolefin is used as a sheath component, and a thermoplastic polymer with a melting point of 150°C or higher is used as a core component, resulting in good durability. It becomes possible to provide a heat-adhesive conjugate fiber having hydrophilic properties.

[Brief explanation of the drawing]

The figure is a fiber cross-sectional view showing the composite form of the thermoadhesive composite fiber used in the example of the present invention.

Claims (1)

[Claims] 98 to 40% by weight of polyolefin and ethylene units (
Contains 20 to 95% of A) and 80 to 5% by weight of one or more polyalkylene glycol (meth)acrylate units (B) represented by the following formula, and has a contact angle with water of 80% in a film state. The sheath component is a blended polymer with 2 to 60% by weight of hydrophilic polyolefin, which is an ethylene copolymer with a temperature of 150°C or less, and the core component is a thermoplastic polymer with a melting point of 150°C or higher, and the ratio of the sheath component to the core component is 20:80. ~80:
20. A heat-fusible composite fiber characterized in that ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R_1, R: hydrogen or methyl group, 1≦n≦9)