JPH09209216A - Self-crimping conjugate fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new conjugate fibers having excellent self-crimping property with spontaneous decomposition property and slight environmental pollution. SOLUTION: The objective self-crimping fibers have respective single fiber in which a polymer 1 mainly comprising an aliphatic polyester having >=100 deg.C melting point and >=30J/g endothermic amount at melting and a polymer 2 mainly comprising an aliphatic polyester having >=100 deg.C melting point and an endothermic amount at melting of >=5J/g lower than the endothermic amount of the polymer 1 are eccentrically conjugated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel composite fiber which is naturally degradable and has excellent texture and spontaneous crimping property.

[0002]

2. Description of the Related Art Conventional synthetic fibers made of synthetic resin have a slow decomposition rate in a natural environment and generate a large amount of heat upon incineration. Therefore, it is necessary to review the natural environment from the viewpoint of protecting the natural environment. For this reason, naturally decomposable fibers made of aliphatic polyesters are being developed and are expected to contribute to environmental protection. Some of the aliphatic polyesters have excellent fiber performance and are expected as a new characteristic fiber material, but there are unsatisfactory points in terms of bulkiness, texture and the like, and improvement thereof is desired.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel conjugate fiber which is naturally degradable and has excellent bulkiness, texture and stretchability.

[0004]

The above object of the present invention is to provide a polymer (1) which comprises an aliphatic polyester as a main component and has a melting point of 100 ° C. or more and an endothermic amount of 30 joules / gram or more when melted, and an aliphatic compound. Polyester as the main component, melting point 10
A polymer (2) having an endothermic amount at 0 ° C. or higher and at the time of melting thereof, which is smaller than that of the polymer (1) by 5 diule / gram or more,
This is achieved by a spontaneously crimping conjugate fiber characterized by being eccentrically conjugated within a single fiber.

Here, the polymer containing an aliphatic polyester as a main component means (1) a hydroxyalkylcarboxylic acid such as glycolic acid, lactic acid or hydroxybutylcarboxylic acid, (2) glycolide, lactide, butyrolactone or caprolactone. Aliphatic lactones such as (3) aliphatic diols such as ethylene glycol, propylene glycol, butanediol, hexanediol, etc.
(4) Polyethylene ether oligomers such as diethylene glycol, triethylene glycol, ethylene / propylene glycol, dihydroxyethyl butane, etc., polyethylene glycol, polypropylene recall, polyalkylene glycols such as polybutylene ether, (5) polypropylene carbonate, polybutylene Polyalkylene carbonate glycols such as carbonate, polyhexane carbonate, polyoctane carbonate, polydecane carbonate and their oligomers, (6) succinic acid, adipic acid, suberic acid,
An aliphatic polyester containing a component derived from an aliphatic polyester polymerization raw material as a main component, that is, 50% by weight or more (particularly 60% or more), such as an aliphatic dicarboxylic acid such as azelaic acid, sebacic acid, and decanedicarboxylic acid. Homopolymers, blocks of aliphatic polyester or /
And random copolymerization polymer, and other components such as aromatic polyester, polyether, polycarbonate, polyamide, polyurea, polyurethane, polyorganosiloxane, etc., in the aliphatic polyester, up to 50% by weight (block or / and random) copolymerization And /
Or a mixture thereof.

The purpose of modifying the aliphatic polyester by copolymerization or mixing is to lower the crystallinity, lower the melting point (lower the polymerization temperature and molding temperature), improve the flexibility and elastic recovery, heat resistance, and glass transition temperature. And reduction or increase in heat shrinkability, improvement in friction coefficient, dyeability, hydrophilicity and water repellency, improvement in adhesiveness with other components, improvement or suppression of degradability, and the like.
The fiber of the present invention is a polymer (1) having a large endothermic amount when melted.
The two component polymers, namely, the polymer (2) having a small heat absorption amount at the time of melting, are combined (bonded). Here, the endothermic amount at the time of melting was measured by using a scanning differential calorimeter (hereinafter referred to as DSC) using a sample sufficiently stretched, heat-treated and dried.
Approximately 10 mg sample weight in nitrogen, heating rate 10 ° C / min
It was measured under the conditions. FIG. 7 schematically shows the DSC curve. The figure shows a measurement example of a sample that is hardly crystallized, 4 indicates a change in baseline due to glass transition, 5 indicates an exothermic peak of crystallization due to heating during measurement, and 6 indicates an endothermic peak due to melting of crystals. . The exothermic peak 5 disappears and is not observed in the fully crystallized sample. In the present invention, an endothermic peak 6 due to melting of crystals
The minimum value (center value) of is the melting point, and the total endothermic amount of the endothermic peak 6 (integral value, proportional to the shaded area in FIG. 7) is the endothermic amount during melting. The unit of the heat absorption is joule / gram (hereinafter referred to as J / g). When there are a plurality of melting points in a mixture or block copolymer, the highest melting point is defined as the melting point (in the present invention). However, when the endothermic peak at the highest temperature is negligible, for example, with an endothermic amount of 2 J / g or less, and when there is a main peak at a lower temperature, for example, with an endothermic amount of 20 J / g or more, the substantial melting point (polymer is Extremely softening, the temperature at which the flow starts) may be the main peak. The melting endotherm is the sum of all melting endotherms.

The polymer (1) is a component having high crystallinity and small heat shrinkability. Suitable as the polymer (1) are a crystalline homopolymer, and a small amount (for example, about 40% by weight or less, particularly 30% or less) of the second component or the second component or the second component, which does not impair the crystallinity. The thing which copolymerized or / and mixed three components is mentioned. From the viewpoint of the crimpability, strength, and heat resistance of the fiber of the present invention, the endothermic amount of the polymer (1) when melted is required to be 30 J / g or more, particularly preferably 35 / g or more, and 40 J / g or more. Is most preferred. The melting endotherm of the homopolymer of the crystalline aliphatic polyester is often around 50 J / g. Similarly, from a practical point of view, the melting point of the polymer (1) needs to be 100 ° C. or higher, preferably 110 ° C. or higher, particularly preferably 130 ° C. or higher, most preferably 150 ° C. or higher.

Specific examples of the preferred polymer (1) include polybutylene succisuccinate (melting point: about 116).
C), poly L-lactic acid (175 ° C.), poly D-lactic acid (175 ° C.), polyhydroxybutyrate (180 ° C.)
C.), homopolymers such as polyglycolic acid (at 230.degree. C.), and those obtained by copolymerizing and / or mixing a small amount of other components. Generally, in block copolymerization, changes in crystallinity and melting point are gradual, and the proportion of the copolymerization component is 50% or less, particularly 1 to 40%, often 1 to 30%.
%, The crystallinity and melting point change remarkably in the random copolymerization, and the ratio of the copolymerization component is often 0.5 to 10%, particularly preferably 1 to 5%. Of course, changes in melting point and crystallinity due to copolymerization greatly vary depending on the copolymerization component, so it is necessary to pay attention to the melting endothermic amount and melting point of crystals by DSC. The changes in melting point and crystallinity due to the mixing of other components also vary considerably depending on the mixing components and the mixing ratio, but they are often not as remarkable as in random copolymerization.

The polymer (2) is a component having low crystallinity and high heat shrinkability. Suitable examples of the polymer (2) include those in which the melting endothermic amount of crystals is lowered by copolymerization or mixing. The difference between the melting endotherm of the polymer (2) and the melting endotherm of the polymer (2) needs to be 5 J / g or more, and 10 J / g or more is preferable for strong crimping, and 1
It is particularly preferably 5 J / g or more. 5 J / g corresponds to about 10% of the melting endotherm of the crystalline aliphatic homopolyester. That is, the crystallinity of the polymer (2) is about 90% or less (estimated) of that of the polymer (1).

Generally, a strong crimp is preferable for knitting or the like which requires a large stretchability, but in order to give softness, bulkiness and a favorable texture to a woven fabric or the like, when a crimp which is suppressed to some extent is preferable. Therefore, the polymer (2) can be selected according to the purpose of use. From a practical point of view, the melting point of the polymer (2) needs to be 100 ° C or higher, preferably 110 ° C or higher, particularly preferably 130 ° C or higher, most preferably 135 ° C or higher. Examples of such polymers having a relatively high melting point include copolymers and mixtures containing the high melting point homopolymer as a main component (50% by weight or more). The components used for copolymerization and mixing can be appropriately selected from the above-mentioned aliphatic polyester polymerization raw materials. Particularly preferred block copolymers and mixed components include aliphatic polyesters having a glass transition temperature of room temperature or lower, particularly 0 ° C. or lower, such as polycaprolactone, ethylene glycol, propylene glycol, butanediol,
A combination of one or more aliphatic glycols such as hexanediol, octanediol, diethylene glycol, triethylene glycol and one or more aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, octanedicarboxylic acid, and decanedicarboxylic acid. Polyesters such as polyethylene succinate, polybutylene succinate, polyethylene adipate, polybutylene adipate, polyethylene sebacate, polybutylene sebacate and the like.

The polymer (2) needs to have low crystallinity as described above. The most effective method for reducing the crystallinity is random copolymerization. Examples of easily random copolymerizable L-lactic acid / D-lactic acid, L-lactide (LL lactide) / D-lactide (DD lactide, DL lactide), lactic acid / glycolic acid, lactide / glycolide, lactide / Optical isomers such as caprolactone, combinations of different hydroxycarboxylic acids, combinations of different lactones, or hydroxycarboxylic acids, glycols,
Examples thereof include a method of copolymerizing two or more kinds of dicarboxylic acids and the like. Further, a combination of random copolymerization, block copolymerization, and mixture of different polymers is also preferable. The polymer (2) does not have to be crystalline. In the case of amorphous, the melting point is the temperature at which the melt viscosity becomes 100,000 poise.

The composite structure of polymer (1) and polymer (2) must be eccentric. Eccentric means a relationship in which the center of gravity of the polymer (1) and the center of gravity of the polymer (2) do not match in the cross section. The further apart the centers of gravity of the two components are,
High eccentricity and strong crimpability. Various eccentric composite structures can be selected according to the desired crimpability.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION FIGS. 1 to 6 are cross-sectional views of composite fibers which are specific examples of the composite structure of the present invention. In the figure, 1 indicates the polymer (1), 2 indicates the polymer (2), and 3 indicates the hollow portion. 1 is an example of a parallel type with high eccentricity, and FIG. 2 is an eccentric core-sheath type with eccentricity 10).
Is a keyhole type, FIG. 4 is an eccentric two-core type, FIG. 5 is a non-circular parallel type, and FIG. 6 is a hollow parallel type. Any composite structure other than FIGS. 1 to 6 in which both components are arranged eccentrically can be applied to the present invention. Further, in addition to the polymer (1) and the polymer (2), a third component can be combined. For example, a third polymer may be arranged instead of the hollow portion in FIG.

The composite ratio (cross-sectional area ratio) of the polymer (1) and the polymer (2) is not particularly limited and may be arbitrarily selected according to the purpose. Generally, as shown in FIG. 1, when the composite ratio is 1/1, the crimpability is strongest, and the further the composite ratio is, the weaker the crimpability is. In many cases, the composite ratio is 1/10 to 10
The range of / 1, particularly the range of 1/5 to 5/1 is preferable, and 1
The range of / 3 to 3/1 is most widely used.

The difference in shrinkage between the polymer (1) and the polymer (2) in the case of fiber is not particularly limited, but usually 3
% Or more, particularly preferably about 5 to 70%, and 10 to 50%
The range of degrees is most widely used.

In many cases, it is preferable that the polymer (1) and the polymer (2) have high mutual adhesiveness, but even if the adhesiveness is poor, the core-sheath type can prevent peeling. Also,
For example, it is also possible to obtain a product of a thin and soft fiber having a non-circular cross section by compounding a material having weak adhesiveness in a parallel type or the like to form a knitted woven fabric and then separating both components. Again,
The different shrinkage and mixing effect due to the difference in shrinkage between the two components gives the product a favorable texture.

The cross section of the fiber of the present invention can be arbitrarily selected from a circular shape, an oval shape, a gourd shape, a polygonal shape, a multilobe shape, an alphabetical shape and various other non-circular shapes (atypical shapes), a hollow shape, and the like. Similarly, the fineness is arbitrarily selected according to the purpose of use,
For ordinary clothing, the range of single yarn fineness of 0.1 to 50 denier (d), particularly 0.5 to 30 d is preferably used. Thinner and thicker materials are used for non-woven fabrics, leather, and materials.

The fiber of the present invention can be produced by composite spinning of the polymer (1) and the polymer (2) by a melt, wet, dry, dry-wet or other method, but the melt spinning is particularly efficient. Is highly preferred. The melt spinning is performed at a winding speed of 500 to 2
000m / min low speed spinning, winding speed 2000-50
High speed spinning at 00m / min, winding speed 5000m / mi
Ultra high-speed spinning of n or more is possible, and stretching and heat treatment can be performed as necessary. Generally, 3-6 for low-speed spinning
Approximately twice, in high-speed spinning, about 1.5 to 2.5 times is stretched, and in ultra-high-speed spinning, stretching is often unnecessary or about 2 times or less. A so-called spin draw method in which spinning and drawing are continuously performed can also be preferably applied.

Similarly, a method such as a melt blow method, a flash spinning method, or a spun bond method, in which the polymer (1) and the polymer (2) are compounded and spun from an orifice and simultaneously made into a nonwoven fabric, can be applied. .

The conjugate fiber of the present invention may be in any form such as continuous filament, monofilament, multifilament, cut staple and the like depending on the purpose of use. Also, during the manufacturing process of fibers and yarns, knitted fabrics, woven fabrics,
After forming a fibrous structure such as a non-woven fabric, it can be contracted by heating, swelling, or the like to be spontaneously crimped. of course,
If necessary, it is also possible to spontaneously crimp by heating after applying crimping mechanically by false twisting or indentation method in the form of thread.
For example, spontaneous crimping is widely performed in a dyeing finishing step. Heating is performed by dry heat, wet heat, infrared rays or any other means. Generally, spontaneous crimping is often performed in a relaxed state, but crimping can be controlled by applying appropriate tension.
The necessary crimp strength depends on the purpose of use and is not particularly limited, but in many cases, the crimp extension ratio is preferably 50% or more, particularly preferably 100% or more, most preferably 150% or more, and 100 to 600. % Is the most widely used.

The composite fiber of the present invention contains various pigments, dyes, colorants, water repellents, water absorbing agents, flame retardants, stabilizers, antioxidants,
UV absorber, metal particles, inorganic compound particles, crystal nucleating agent,
Lubricants, plasticizers, antibacterial agents, fragrances and other additives can be mixed.

The fibers of the present invention can be used alone or in combination with other fibers to produce yarns, strings, ropes, knits, woven fabrics, nonwoven fabrics, papers, composite materials and other structures. When mixed with other fibers, natural organic fibers such as cotton, wool and silk,
It is particularly preferable to use it in combination with a naturally degradable fiber such as an aliphatic polyester fiber because a completely naturally degradable product can be obtained.

[0023]

EXAMPLES In the following examples,% and parts are by weight unless otherwise specified. The molecular weight of the aliphatic polyester is
In GPC analysis of a 0.1% chloroform solution of a sample, it is a weight average value of dispersion of a high molecular component excluding a component having a molecular weight of 1,000 or less.

The crimp extension ratio of the composite fiber is about 1000 (950 to 1050) denier and a length of 5 for the sample filament.
It is made into a bundle of 0 cm, treated in boiling water for 10 minutes with no load, and then centrifugally dehydrated, and 2 with no load in a measuring room at 23 ° C and 65%.
After air-drying for 4 hours or more, a load of 0.5 g is applied to the length L1 after 1 minute, and a load of 500 g is applied to the length L after 1 minute.
2 is measured and [(L2-L1) / L1] x 100 (%)
Calculate by the formula.

[Example 1] 3 parts of polyethylene glycol (PEG) having a molecular weight of 8000 and hydroxyl groups at both ends, 98 parts of L-lactide, 100 ppm of tin octylate, and 0.1 part of Irganox 1010, an antioxidant of Ciba-Geigy. The mixture was mixed, melt-stirred and polymerized in a twin-screw extruder at 190 ° C for 12 minutes in a nitrogen atmosphere, and after cooling into chips, it was treated for 4 hours in a nitrogen atmosphere at 140 ° C (solid phase polymerization) to obtain polylactic acid. A PEG block copolymer P1 was obtained. Polymer P1 has a molecular weight of 153,000 and a PEG component content of about 3
%, The melting point was 174 ° C., and the melting endotherm when fully oriented and crystallized was 55 J / g. Almost the same as Polymer P1, except that L-lactide as lactide is 95.5.
Parts, D-lactide 2.5 parts mixture, polymer P
2 was obtained. Polymer P2 had a molecular weight of 158000, a melting point of 163 ° C., and a melting endotherm of 27 J / g.

Polymer P1 and polymer P2 are separately melted by a screw extruder at 220 ° C. and supplied to two polymer supply parts of the composite spinneret. Both polymers were compounded in a parallel type (composite ratio 1/1) as shown in the figure, spun through an orifice with a diameter of 0.25 mm and 225 ° C, cooled in air, and wound at a speed of 1500 m / min while oiling. 70 denier / 2 by stretching 4.5 times at ℃
A 4-filament stretched yarn F1 was obtained. The drawn yarn F1 had an excellent strength of 4.6 g / d, an elongation of 29%, and a crimp extension ratio of 226% after the crimp was developed.

For comparison, the polylactic acid homopolymer obtained in substantially the same manner as polymer P1 but without PEG is designated as P3. Polymer P3 has a molecular weight of 162000,
The melting point was 175 ° C. and the melting endotherm was 55 J / g. Similar to Polymer P1, except that 6 parts of PEG,
A polymer P4 was obtained by using 95 parts of L-lactide. Polymer P4 had a molecular weight of 155,000 and contained about 6% PEG as a copolymerization component, but had a melting point of 173 ° C. and a melting endotherm of 55 J / g. Using the polymers P3 and P4, a drawn yarn F2 (comparative example) was obtained in the same manner as the drawn yarn F1. The drawn yarn F2 has a strength of 4.8 g / d and an elongation of 3
The crimp expansion ratio was 1%, and the crimp elongation ratio after the crimp development was 19%, indicating that the crimp property was extremely weak.

Example 2 Almost the same as the polymer P1 of Example 1, except that the molecular weight was 12700 instead of PEG.
Polymer P5 was obtained by using 30 parts of polybutylene succinate having 0 and a hydroxyl group at the terminal. Polymer P5 has a molecular weight of 1
It had a melting point of 29000 and a melting endotherm of 35 J / g. Similar to polymer P1 except that P
A polymer P6 was obtained in which 10 parts of polybutylene succinate having a molecular weight of 127,000 and a hydroxyl group at the terminal was used instead of EG, 88.5 parts of L-lactide and 2.52 parts of D-lactide instead of L-lactide. Polymer P6 has a molecular weight of 1
The melting point was 3400, the melting point was 151 ° C, and the melting endotherm was 26 J / g.

Almost the same as the drawn yarn F1 of Example 1,
However, a drawn yarn F3 was obtained using the polymers P1 and P5. The drawn yarn F3 has a strength of 4.7 g / d, an elongation of 28%,
The crimp extension ratio was 223%, and the crimp property was excellent.

Similarly to the drawn yarn F1 of Example 1, except that the polymer P1 and the polymer P6 are used to draw the drawn yarn F.
4 was obtained. The drawn yarn F4 has a strength of 4.6 g / d and an elongation of 29.
%, The crimp extension ratio was 236%, and the crimp property was excellent.

[0031]

Industrial Applicability According to the present invention, there is provided a novel composite fiber which is naturally degradable, has little environmental pollution, and is excellent in spontaneous crimping property. As a result, a soft, highly stretchable and elastic product was obtained, and it can be suitably used for clothing, industrial materials, industrial materials, household products, and the like. In general,
The aliphatic polyester fiber not only decomposes in the natural environment, but also has a smaller calorific value upon combustion than the conventionally used synthetic fiber and is easy to incinerate. In particular, since lactic acid is obtained from agricultural products by a fermentation method or the like and is incorporated into a natural substance circulation system, an aliphatic polyester containing polylactic acid as a main component is most preferable from the viewpoint of environmental protection.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a preferable side-by-side conjugate fiber for the present invention.

FIG. 2 is a cross-sectional view of an eccentric core-sheath type composite fiber that is preferable for the present invention.

FIG. 3 is a cross-sectional view of a keyhole type conjugate fiber which is preferable for the present invention.

FIG. 4 is a cross-sectional view of an eccentric twin-core type core-sheath type composite fiber according to the present invention.

FIG. 5 is a cross-sectional view of a non-circular side-by-side conjugate fiber that is preferable for the present invention.

FIG. 6 is a cross-sectional view of a hollow side-by-side conjugate fiber that is preferable for the present invention.

FIG. 7 is an example of an exothermic and endothermic curve at the time of heating, which illustrates exothermic and endothermic peak measurement by a scanning differential calorimeter (DSC).

[Explanation of symbols]

1: Polymer with high melting endotherm (1) 2: Polymer with low melting endotherm (2) 3: Hollow part 4: Change of baseline due to glass transition 5: Exothermic peak due to crystallization 6: Due to melting of crystal Endothermic peak

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[Procedure amendment]

[Submission date] February 14, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshikazu Kondo, Inventor 2-5-31, Kokubun, Hofu City, Yamaguchi Prefecture (72) Hiroshi Kajiyama 4-1 Kanebocho, Hofu City, Yamaguchi Prefecture

Claims (2)

[Claims] 1. A melting point of 1 containing an aliphatic polyester as a main component.
A polymer (1) having a heat absorption of not less than 30 ° C. and not less than 100 ° C. and a melting point of 100 ° C. or more and having an endotherm at the time of melting (1) 5. The spontaneously shrinkable conjugate fiber, wherein the polymer (2), which is 5 diules / gram or more less than that of the above), is eccentrically conjugated within the single fiber. 2. The polymer (1) has a melting point of 130 ° C. or higher, an endotherm of 40 joules / gram or more when melted, and an endotherm of the polymer (1) and the polymer (2) when melted. Difference of 1
The fiber according to claim 1, which has a content of 0 joule / gram or more.