JPS61201059A - Composite fiber nonwoven structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a nonwoven structure mainly composed of composite short fibers having adhesive properties. More specifically, the present invention relates to a nonwoven structure mainly composed of conjugate short fibers substantially composed of a polyester polymer and a polyolefin polymer having carboxyl groups in side chains. The nonwoven structure is a dry nonwoven fabric,
It can be used in fields such as wet-processed nonwoven fabrics, and specific fields include sanitary materials such as sanitary napkins and disposable diapers; civil engineering materials; packaging materials such as floppy liners, and filters.

Examples include various felts, hard cotton futons, base fabrics, building materials, interior materials for automobiles, etc.

BACKGROUND TECHNOLOGY Conventionally, methods for producing nonwoven structures using a single binder method include, for example, a binder chemical liquid immersion method, a binder chemical spray method, a binder powder method, etc., and Japanese Patent Application Laid-open No. 58-18.
There are various methods of blending heat-fusible m-fibers, such as that disclosed in Japanese Patent No. 0652.

Of these methods, the binder chemical method and the powder method have had problems in recent years, such as high raw materials and fuel costs and deterioration of the working environment.
The all-melt type blending method for heat-fusible fibers has the disadvantage that the adhesive fibers lose their shape and become bead-like, resulting in weak bonding strength and, depending on the ingredients, they become powdery and easily fall off.

On the other hand, a uniform conjugate type whose main component is a polyester polymer obtained by the orifice-type melt spinning method, which has been attracting attention in recent years, is published in Japanese Patent Application Laid-Open No. 57-10817.
No. 7, JP-A-58-41912.

Japanese Patent Publication No. 57-37637, Japanese Patent Publication No. 57-9531
Although this method is disclosed in Publication No. 1, etc., it is expensive, and when the burial grade polyester is used as an adhesive component, powder tends to fall off. Further, in this method, a nonwoven structure is obtained by mixing 5 to 50% by weight of short fiber cotton produced by the ordinary orifice type melt spinning method, but it has the drawback that it is extremely difficult to mix uniformly.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a novel polyester nonwoven structure that can overcome the drawbacks of the prior art as described above.

That is, as a result of extensive research into conjugate-type self-adhesive fibers that do not use binder chemicals and are mainly composed of polyester polymers, the inventors found that the combination of polyester polymers and specific polyolefin polymers does not work at all. The present invention was achieved by discovering that there is an unexpectedly excellent adhesion effect.

Configuration of the Invention Namely, the present invention provides a non-woven structure mainly composed of composite short fibers having adhesive properties, wherein (A) the composite short fibers are used at least 50% for all times of the nonwoven structure; (1) The composite short fibers are made of polyester (polymer A) having at least 80 mol% of ethylene terephthalate units;
) and a polyolefin (polymer B) having a carboxyl group (-C00H) in the side chain and having a melting point of 60°C to 140°C, (a) Both 50% are
It has at least two blocks that are joined side-by-side with at least a portion of each of Polymer A and Polymer B exposed around the composite short fibers, and the shape or size of the blocks (B) the nonwoven structure is joined via polymer B constituting the composite short fibers, and has an apparent density of 0.002
It is a composite fiber nonwoven structure characterized by being in the range of ~0.35 g/-.

The composite nonwoven structure of the present invention has the following characteristics compared to a nonwoven structure using a single binder.

First, since it does not use chemicals such as binders, it is safe and hygienic since there is no fear of drug elution.

Second, the cost of the binder can be omitted, and the conjugate fiber nonwoven structure of the present invention can be obtained at a much lower cost and in an energy-saving manner than the energy required to evaporate water in the binder.

Thirdly, the composite fiber of the present invention does not require wastewater treatment equipment, which is required when using chemicals such as binders, and there is no need for cleaning such as changing binder brands, and the manufacturing work environment is very good. It has the characteristic that a nonwoven structure can be obtained.

Furthermore, since the composite short fibers described in the present invention have a conjugate structure, they have the following characteristics in contrast to conventional adhesive fibers made of 100% low melting point components.

In other words, conventional adhesives made of 100% low melting point components!
The adhesive fibers easily lose their shape by heat treatment above their melting point, become beaded, and are mixed to form the base.
Since it is easy to move to the bonding point of the fiber aggregate, only a smaller number of bonding points can be obtained than the bonding points of the adhesive fiber and the base fiber. In this way, for conventional adhesion! When using a nonwoven fabric, the strength of the nonwoven structure is weak because there are few bonding points, and the texture of the nonwoven structure is poor because it forms beads at the bonding points and is fixed with adhesive. It is difficult to clean and easily causes powder to fall off.

However, since the composite short fibers having adhesive properties of the present invention basically have a conjugate structure, the formed nonwoven structure has many bonding points, and the low melting point polymer phase of the composite short fibers has many bonding points. Because it is joined to other composite short fibers and other types of staples to be mixed through the point bonding method,
It has the characteristic that it does not have a hard texture.

Furthermore, the composite fiber of the present invention is disclosed in Japanese Patent Publication No. 57-376, for example.
37, JP-A-57-108177, JP-A-57-95311, and JP-A-58-41912, which disclose uniform conjugates containing polyester polymers as main components. It has the following characteristics compared to structures.

That is, conventional composite fibers mainly composed of polyester-based polymers as described above use non-grade polyesters or low-melting point polyesters as adhesive components (for example, aliphatic dicarboxylic acids are used as dihydrochloric acid components, or butanediol is used as glycol components). However, it can be manufactured at a lower cost than these.
Moreover, since it is a non-uniform conjugate structure, it is more prone to point adhesion than a uniform conjugate structure which tends to form linear adhesion, and it is possible to provide a random crimp structure if desired, resulting in high bulk. A structure with good texture and texture can be obtained.

Furthermore, there are no drawbacks such as powder shedding that occurs when non-grade polyester is used.

The composite fiber of the present invention has a content of 50% relative to the total amount of the nonwoven structure.
A composite fiber nonwoven structure is obtained by using an amount equivalent to ~100%, but since the raw material cost is low, the overall price is not high, and since the proportion of composite short fibers is relatively high, the nonwoven structure is The amount of composite short fibers mixed in the structure is reduced. In particular, when 100% composite short fibers are used, the mixing step can be omitted. Furthermore, in the present invention, since the mixing ratio of composite short fibers is high, the point adhesion is improved, and the adhesion strength can be improved while the drapability of the nonwoven structure is maintained in a good state.

As explained above, the composite fiber nonwoven structure of the present invention has excellent advantages such as adhesive performance, texture, and production cost.

Next, the present invention will be explained in more detail.

The composite short fibers in the present invention are composed of a polyester (polymer A) containing at least 80 mol% of ethylene terephthalate units and a modified polyolefin (polymer The low melting point polymer phase (polymer B) consists essentially of the coalesced B)
It is characterized by exhibiting fusion performance above the melting point or softening point of .

Furthermore, at least 5 in any cross section of the composite staple fiber of the present invention
0%, preferably 80% or more, more preferably 90% or more, most preferably 95% or more of at least two different fiber-formable polymer phases, each at least partially surrounding the fibers of each other. It is characterized in that it has at least two blocks that are joined side by side in a state where the blocks are exposed, and that there is at least a cross section in which the blocks have different shapes or sizes.

The polyester constituting the polymer A may contain at least 80 mol% of ethylene terephthalate units, and preferably has a melting point of 170°C or higher. Examples of units other than ethylene terephthalate units include ethylene isophthalate units, propylene terephthalate units, trimethylene terephthalate units, butylene terephthalate units, propylene isophthalate units, and ethylene adipate units.

On the other hand, examples of modified polyolefins used as polymers include acrylic acid, methacrylic acid, and maleic acid.

itaconic acid, citraconic acid, hymic acid, bicyclo(
2,2,2) Ophter-5-ene-2,3-dicarboxylic acid, 4-methylcyclohex-4-ene-1,2-dicarboxylic acid, 1,2,3,4,5,8,9.10- Octahydronaphthalene-2,3-dicarboxylic acid, bicyclo(2
, 2,1) oct-7-ene-2,3,5,6-tetracarboxylic acid, 7-oxabicyclo(2,2,1)but-5-ene-2,3 dicarboxylic acid, etc. Examples include direct copolymers of carboxylic acids and their anhydrides with ethylene, and materials containing metal ions such as ionomer resins may also be used.

The composite fibers of the present invention have an average fineness of 0.5 to 50.
It is preferably in the range of 0 de, preferably in the range of 0.5 to 400 de, more preferably in the range of 1.0 to 300 de.

Further, the average fiber length of the composite short fibers used in the present invention is 2
Range of 04m1 to 500M, preferably 25m to 400m
It is desirable that the length be within the range of 30#W to 300m, more preferably 30#W to 300m.

It is more preferable that the composite short fibers of the present invention have crimps in a random structure. The rate of crimp is the compound short! If the fineness of the fiber is less than 10 de, the number of crimps is 5 strands/1 nch or more, more preferably 7 crimps/+ nch or more, and if the fineness of the composite staple fiber is 10 den or more and less than 100 den, the number of crimps is 2. More than 3 pieces/1 nch, more preferably 3 pieces/1 nc
When the number of crimps is at least h and the fineness of the composite short fiber is 10,068 or more and less than 500 de, the number of crimps can be at least 0.5 crimp/1 noh, more preferably at least 1 crimp/1 nch.

The mixing ratio of the low melting point polymer phase (polymer B) and the high melting point polymer phase (polymer A) constituting the composite short fibers of the present invention is 60:40 to 20:80, preferably 55 by weight. :4
5 to 25 nia 5, most preferably 50:50 to 30 nia 0, and as a method of increasing the adhesive strength of the composite II fibrous nonwoven structure of the present invention, It is possible to combine measures to increase the blending ratio in the fibrous nonwoven structure and measures to increase the mixing ratio of the low melting point polymer phase in the composite short fibers, and it is possible to maintain good texture. It is characterized by points.

In addition, in the present invention, other stable fibers may be blended in addition to the conjugate short fibers constituting the conjugate fiber nonwoven structure, and the remaining stable m fibers used for the small amount of blending are generally Refers to synthetic fibers, chemical fibers, and natural fibers used for clothing and industrial purposes; 120℃
All fibers can be used except those whose fiber performance is reduced to 50% or less after heat treatment for 5 minutes.

Examples of stable synthetic fibers include polyester, nylon, vinylon, vinylidene, polyvinyl chloride,
Examples include fibers such as acrylic, boria pyrene, and polyethylene, and examples of stable chemical fibers include rayon and cupro.

Examples of natural fibers include fibers such as cotton, linen wool, silk, etc., and any combination of these fibers may be used.

The average fineness of the stable fibers for blending constituting the composite fiber non-n structure of the present invention is in the range of 0.5 to 500 de, preferably in the range of 1 to 300 de; It is common practice to make the average fineness of the composite short fibers, which are the main constituent components, close to each other. Further, pigments, flame retardants, stabilizers, fluorescent whitening agents, etc. may be mixed with the constituent components of the composite short fibers.

Next, the composite fiber nonwoven structure of the present invention will be explained in further detail.

The composite fiber nonwoven structure of the present invention has an apparent density of 0.0.
It is in the range of 0.02 to 0.35 g/ci, and compared to conventional nonwoven fabrics, it is characterized by high adhesive strength despite its low apparent density.

In order to exhibit various advantageous characteristics of the composite fiber nonwoven structure of the present invention, the mixing ratio of composite staple fibers is at least 50% of the total R of the composite mH nonwoven structure as described above.
Weight%. A more preferable range of the mixing ratio of the composite short fibers is such that the apparent density of the nonwoven structure is 0.00.
In the range of 2 g/cII or more and less than 0.01 g/cm3, the composite 5r1 fiber is
The nonwoven structure has an apparent density of 0.01 g/cd or more, 0.1 g/CI! When the composite staple fibers are less than 60% by weight based on the total amount of the nonwoven structure, the nonwoven structure has an apparent density of 0.5% by weight.
In the range of 1 g/cd or more and less than 0.359/cd, it exceeds 50% by weight based on the total amount of the nonwoven structure.

An example of the method for producing the composite staple fiber of the present invention is that it can be easily produced by the method described in the specification of Japanese Patent Application Laid-open No. 70712/1983, which was proposed by some of the inventors of the present invention. In other words, a polyester polymer (polymer A) is extruded from one extruder using two extruders, a modified polyolefin (polymer B) is extruded from the other extruder, and the mixture is statically mixed in a part of the adapter that is combined with the piping. vessel (e.g. K
Using an entcs type static mixer, the melted polyester polymer and the melted modified polyolefin are mixed into a suitable layered state, and then sent to a type 1 die and uniformly discharged.

The fiber molding area consists of a concavo-convex porous die (for example, a die made of one mesh wire mesh [mesh size #8 to #70]), and the die is used as a partition member for the molten mixed polymer. The countless rivulets of the molten mixed polymer extruded from the uneven porous nozzle are cooled by cooling air jetted from a cooling device near the top of the nozzle, while being drafted from bottom to top at 1 m/min. The fibers are pulled off at a speed of about 20 yyt/min to form fibers into uniform, densely arranged fiber bundles.

The obtained fiber bundles are straight-stretched to about 2 to 5 times, applied with an oil agent, bundled, cut into a desired fiber length using a cutter at a constant speed, and further crimped with hot air. Also, mechanical crimp may be applied before cutting. In this way, the complex IIM is obtained. The mixing state and fineness of the polyester polymer and modified polyolefin can be easily controlled by the number of static mixers used as mixers and the size of the mesh wire mesh used as the uneven mouthpiece.

The method for producing composite short fibers of the present invention described above is not limited to this.

The conjugate short fibers thus obtained may be used as they are at 100%, or if mixed with other short fibers and made into wear using a carding machine, the conjugate fiber nonwoven fabric of the present invention becomes an unprocessed product. This web may be thermocompressed using a predetermined heated nip roller, or may be thermally processed into a predetermined shape. As a heating method, a conventional method such as a hot air type, an infrared heater type, a heated roller, etc. may be used.

Example 1 Chips of polyethylene terephthalate (manufactured by Teijin ■: [η] = 0.71) were fed at 245 g/min each from one (A) of two 30φ extruders, and Yucalon EAA, A-201M was fed from the other (B). (Mitsubishi Yuka @: Both ethylene-acrylic acid copolymer and acrylic acid 7wt%.

m, p, = 102° C.) were quantitatively melt-extruded at a rate of 1059/min and merged just before a portion of the adapter. A Kenics type static mixer is arranged in a part of the adapter to mix the mixture, and the concave and convex mouthpiece is used.

Use a 20-mesh plain weave wire mesh to bind the mesh.
A current of 0 A was applied to generate Joule heat, and the tube was pulled upward at a speed of 6 m/min while blowing cooling air. Subsequently, the fibers were drawn approximately 3.5 times using five bars controlled at 60 to 85°C, and the resulting fibers were cut into 95M. The short fibers were heated to 100°C.

Three-dimensional crimp was developed by hot air treatment for 10 minutes. The average fineness was about 50 de, and the cut length was about 80111I11.

This is opened into a wear shape using a card machine and 26Cd/9
Hot air treatment was performed at 150° C. for 10 minutes while maintaining the bulk.

A hard cotton-like polyester futon material with excellent adhesive performance was obtained. As a method for evaluating hardness, a load of 1109/cd was applied and the thickness retention rate at that time was evaluated. The thickness retention rate at this time was 75%.

Example 2 Yucalon E was produced from the B-side extruder using the same equipment as in Example 1.
AAA-221M (manufactured by Mitsubishi Yuka@J: ethylene-acrylic acid copolymer: m, p, 95°C, acrylic acid 8.5
wt%) chips were quantitatively melt-extruded and the other operations were the same as in Example 1 to obtain a polyester futon and hard cotton material. The thickness retention rate was 70%.

Example 3 Using the same equipment as in Example 1, the base was made of 45 mesh plain weave and the cut length was 60 In! The same operation as in Example 1 was carried out except for R, and a composite with an average fineness of 6de was obtained! A web-like material consisting of ll1t was obtained. The web was needle punched to form a felt-like material (q).The felt-like material was subjected to a linear pressure of 2K.
A composite fiber nonwoven fabric with a basis weight of 50 g/g was obtained by thermocompression bonding with a metal rubber roller of g/α at 130°C. The apparent density is 0
．． 10g/cd, adhesive strength is 15Kg15cIR
It was wide.

Comparative Example 1 Using the same equipment as in Example 1, chips of polyethylene (Tubatic LL MK-40 manufactured by Mitsubishi Kasei ■) were quantitatively melted and extruded from the B-side extruder, and futon hard cotton was otherwise produced in the same manner as in Example 1. I got something like that.

The thickness retention rate at that time was 45%, indicating that the adhesive performance was very poor. Also, fibrillation in the card was very large.

Comparative Example 2 A composite fiber nonwoven fabric was obtained by carrying out the same operations as in Example 3, except that polyethylene (Tsubachik LL MK-40 manufactured by Mitsubishi Kasei@) chips were melt-extruded from the B-side extruder. The adhesive strength was 3 to 915 crn.

Example 4 3, Od, consisting of the composite staple fiber obtained in Example 3 and polyethylene terephthalate obtained by orifice spinning method
e. A web was obtained by blending 20% of 5F cotton with a cut length of 51 am using a carding machine. Thereafter, a nonwoven fabric was obtained in the same manner as in Example 3. Adhesive strength is 10Kg/5ex
It was wide.

Claims (1)

[Scope of Claims] 1. A nonwoven structure mainly composed of composite staple fibers having adhesive properties, wherein (A) the composite staple fibers are at least 50% by weight based on the total amount of the nonwoven structure; (1) The composite short fibers are composed of a polyester (polymer A) containing at least 80 mol% of ethylene terephthalate units and a carboxyl group (-COOH) in the side chain and a melting point of 60°C to 140°C. (2) at least 50% of any cross section of the composite short fibers consists of polyolefin (polymer B);
It has at least two blocks that are joined side-by-side with at least a portion of each of Polymer A and Polymer B exposed around the composite short fibers, and the shape or size of the blocks (B) the nonwoven structure is bonded via polymer B constituting the composite short fibers, and has an apparent density of 0.002.
A composite fiber nonwoven structure characterized in that it is in the range of ~0.35 g/cm^3. 2. The conjugate fiber nonwoven structure according to item 1, wherein the average fineness of the conjugate staple fibers is in the range of 0.5 to 500 de. 3. The average fiber length of the composite short fibers is 20 mm to 500 mm.
The composite fiber nonwoven structure according to item 1, which falls within the range of . 4. The first composite short fiber has a crimp with a random structure.
Composite fiber nonwoven structure as described in .