JPH0559616A - Conjugate fiber - Google Patents

Abstract

PURPOSE:To provide a conjugate fiber having an excellent elastic performance and giving fiber products having good durability such as good weather resistance, heat resistance and chlorine resistance by bicomponent-spinning a specific block copolyester and a polyester. CONSTITUTION:The objective conjugate fiber produced by bicomponentspinning (A) a block copolyester comprising (i) polyester segments consisting mainly of a phthalic acid compound and a 612C aliphatic alpha,OMEGA-diol and (ii) polyester segments consisting mainly of an aromatic dicarboxylic acid and a 2-4C aliphatic alpha,OMEGA-diol or 1,4-cyclohexanedimethanol and (B) a polyester consisting mainly of terephthalic acid or 2,6-naphthalene dicarboxylic acid and a 2-4C aliphatic alpha,OMEGA-diol, the component A being exposed on the surface of the fiber and having a cross-sectional area ratio of 5-85%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel composite fiber. More specifically, the present invention relates to a composite fiber suitable for producing a fabric or a fiber structure having excellent elastic recovery performance and excellent in durability such as weather resistance, heat resistance and chlorine resistance.

[0002]

2. Description of the Related Art Conventionally, various composite fibers composed of two or more kinds of polymers obtained by composite spinning of two or more kinds of polymers have been proposed and used for various purposes by making use of their respective characteristics. For example, a composite fiber composed of a polymer having excellent elastic recovery performance and a normal fiber-forming polymer is used as an elastic yarn having a limited degree of elongation. However, as the polymer excellent in elastic recovery used for such a composite fiber, since polyurethane or polyether ester block copolymer is generally adopted, light resistance is inferior when used as a bare yarn, A covering thread in which an inelastic thread is wound around an elastic thread is used.

A composite fiber composed of a fiber-forming polymer and a polymer that melts or softens at a lower temperature than the polymer is used as a heat-adhesive fiber, and the low melting point or low softening point polymer may be an elastic polymer. For example, there is a feature that the fiber structure obtained by the heat-bonding treatment exhibits flexible elastic performance. However, since the heat-bonding process is usually performed in the air, the elastic polymer is oxidatively deteriorated,
In some cases, it will burn. Therefore, a method of improving the oxidative deterioration property at the sacrifice of the elastic recovery performance of the elastic polymer, or a method of lowering the melting point or the softening point to lower the thermal bonding treatment temperature is used. There is a problem that the elastic recovery performance and heat resistance are reduced.

[0004]

The present invention does not have the drawbacks of the above-mentioned prior art, and exhibits excellent performance both as an elastic yarn having excellent elastic recovery performance and as a heat-adhesive fiber for producing a fiber structure. It is an object of the present invention to provide a new composite fiber that can be manufactured.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, a composite fiber containing a polyester block copolymer having a specific aromatic polyester as a soft segment as one component The inventors have found that the above problems can be solved and have reached the present invention.

That is, according to the present invention, a polyester segment (A) containing phthalic acids as a main acid component and an aliphatic α, ω-diol having 6 to 12 carbon atoms as a main glycol component, and an aromatic dicarboxylic acid as a main component. As an acid component, an aliphatic α, ω-diol or 1,4-
A polyester segment (B) containing cyclohexanedimethanol as a main glycol component, and satisfying the following (a) and (b) and having a melting point of 150 to 220 ° C.
When the polyester block copolymer (I) of (1) and the component constituting the polyester segment (A) of (a) are polycondensed to form a polyester having an intrinsic viscosity of 0.4 or more, the melting point is 5
The melting point is 180 ° C. when it is less than 0 ° C. or amorphous, and (b) the polyester segment (B) is polycondensed to obtain a polyester having an intrinsic viscosity of 0.4 or more.
The above is a composite fiber comprising terephthalic acid or 2,6-naphthalenedicarboxylic acid as a main acid component and polyester (II) having an aliphatic α, ω-diol having 2 to 4 carbon atoms as a main glycol component. And the polyester block copolymer (I) occupies 5 to 95 area% of the cross section of the conjugate fiber, and at least a part thereof is exposed on the fiber surface. To be done.

One of the polyester block copolymers (I) constituting the conjugate fiber of the present invention is a polyester having phthalic acids as a main acid component and an aliphatic α, ω-diol having 6 to 12 carbon atoms as a main glycol component. A segment (A) and a polyester segment (B) containing an aromatic dicarboxylic acid as a main acid component and an aliphatic α, ω-diol having 2 to 4 carbon atoms or 1,4-cyclohexanedimethanol as a main glycol component; And has a melting point of 1
It is important that the temperature is 50 to 220 ° C.

Examples of the phthalic acids used for the polyester segment (A) include phthalic acid, isophthalic acid, terephthalic acid, etc., but the elastic recovery performance tends to decrease as the proportion of the terephthalic acid component increases. Therefore, it is desirable to set it to 40% or less, preferably 10% or less. Further, the aliphatic α, ω-diol is represented by the general formula HO (CH ₂ ) _n OH, and when the carbon number (n) is less than 6, the elastic recovery performance is deteriorated. If it exceeds the range, not only is it difficult to obtain the raw material, but also the elastic recovery performance is often deteriorated, which is not preferable. Particularly, when elastic recovery performance at low temperature is required, the above n is particularly preferably 8 to 12.

The polyester segment (A) may be copolymerized with a diol component or an acid component other than the above, but the copolymerization amount is 40 mol% or less, preferably 30% with respect to the total acid component. It is not more than mol%. At that time, when the components constituting the polyester segment (A) are polycondensed into a polyester having an intrinsic viscosity of 0.4 or more, the melting point thereof needs to be less than 50 ° C. or amorphous. When the melting point is 50 ° C. or higher, the elastic recovery performance deteriorates, which is not preferable.

As such a copolymerization component, for example, a long chain aliphatic dicarboxylic acid or a polyether glycol such as poly (oxytetramethylene) glycol (in this case, 40% by weight or less with respect to the soft segment (A)) is used. And the elastic recovery performance is improved, while the use of an aromatic dicarboxylic acid such as 2,6-naphthalenedicarboxylic acid can improve the elastic recovery performance without lowering the heat resistance and hydrolysis resistance. Can be selected as appropriate.

If the proportion of the copolymerization component exceeds 40%, the elastic recovery performance, the hydrolysis resistance, the light resistance, etc. are deteriorated, and it becomes unpractical.

Next, examples of the aromatic dicarboxylic acid used for the polyester segment (B) include terephthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid and the like, and aliphatic α, ω -Examples of the diol include ethylene glycol, trimethylene glycol, and tetramethylene glycol. Among them, poly (tetramethylene terephthalate) has the characteristics of good crystallinity and high crystallization speed.
Segment, poly (tetramethylene-2,6-naphthalene dicarboxylate) segment, and poly (1,4
-Cyclohexanedimethylene terephthalate) segment and the like are preferably used.

The polyester segment (B) may be copolymerized with a small amount of a diol component or acid component other than the above, but the copolymerization amount is 30 based on the total acid component.
It is at most mol%, preferably at most 20 mol%. At that time, when the components constituting the polyester segment (B) are polycondensed to form a polyester having an intrinsic viscosity of 0.4 or more, it is important that the melting point is 180 ° C. or more, preferably 200 ° C. or more, If it is less than this range, the elastic recovery performance tends to decrease.

The polyester block copolymer (I) used in the present invention comprises the above polyester segment (A) and polyester segment (B),
The ratio can be arbitrarily changed depending on the purpose. That is, A: B is generally set to 7 in order to impart elastic recovery performance.
It may be in the range of 5:25 to 30:70, but especially when rubber elasticity is desired, there are many A portions 75:25 to 50: 5.
It is desirable to set it to 0 (however, the weight ratio).

The melting point of the polyester block copolymer is preferably in the range of 150 to 220 ° C.
If the temperature is lower than 50 ° C, the obtained composite fiber is likely to stick to each other and the handling property is lowered, or the elastic recovery performance is lowered, which is not preferable. On the other hand, if the temperature exceeds 220 ° C., it is difficult to obtain the polyester segment (A) unless the polyester segment (A) is reduced, so that the elastic recovery performance decreases and the object of the present invention cannot be achieved.

The polyester block copolymer (I) described above is, for example, a high molecular weight polyester (A ') or (B') consisting of the above-mentioned polyester segment (A) or polyester segment (B) alone.
Transesterification (redistribution reaction)
It can be easily obtained. As a method for carrying out the transesterification reaction, a method of melt-mixing the above two kinds of polyesters in the presence of a catalyst is generally used. At this time, "how far to react" and "how to react in that state" Two points are "whether to stop it". The former point can be appropriately changed depending on what kind of characteristics of the polymer is desired to be obtained, and the reaction conditions therefor are as follows: the type, amount and molecular weight of the polyester (A ') and polyester (B') used. It is difficult to unambiguously set the value because it depends on various factors such as stirring conditions, temperature and catalyst. Therefore, in practice, after the polymer, composition, equipment, etc. to be used are determined, the reaction conditions under which the desired polyester block copolymer (I) can be obtained will be found out.

When carrying out this transesterification reaction, the melting point of the obtained polyester block copolymer is
It is important to react the polyester (B ′) used until it becomes 2 to 40 ° C. lower than the melting point. When the melting point is lower than 2 ° C., the transesterification reaction does not proceed sufficiently, and the obtained polymer is a mixture of polyester (A ′) and polyester (B ′) rather than a block copolymer. As a result, it does not exhibit sufficient elastic recovery performance. On the other hand, when the melting point decrease is 40 ° C. or more, the transesterification reaction proceeds too much, the length of the polyester segment (B) of the obtained block copolymer becomes too short, the crystallinity decreases, and the elastic recovery occurs. It is not desirable because the performance becomes insufficient and it becomes substantially equivalent to the random copolymer. Preferably, the 50% elongation elastic recovery rate when the obtained polymer is formed into a fiber is 80.
It is desirable that the reaction be performed so that the content is at least%.

Next, "how to terminate the transesterification reaction" does not always cause a problem when the block copolymer after the reaction is immediately molded, but
For example, when chips are once formed and then melted again to form a molded product, the transesterification reaction further progresses during remelting and the properties of the block copolymer change, so the transesterification reaction should be stopped. desirable. As a method of stopping this reaction, a method of deactivating a catalyst is generally used. For example, a titanium or tin catalyst is used as a transesterification reaction catalyst, and phosphoric acid, phosphorous acid, phosphonic acid, phosphinic acid and their derivatives are used. Can be used to deactivate the catalytic activity.

The polyester block copolymer (I) thus obtained has an intrinsic viscosity (measured in orthophenol at 35 ° C.) of 0.4 or more, preferably 0.6 or more, and is used in the transesterification reaction. This can be easily achieved by using polyesters (A ') and (B') having a high intrinsic viscosity and reacting under the condition that both polymers are not decomposed during the transesterification reaction and the polymerization degree is not lowered. That is, for example, if the reaction temperature during the transesterification reaction is too high, thermal decomposition will occur,
If water, glycol components, etc. coexist in the reaction atmosphere, hydrolysis, glycol decomposition, etc. occur, and the intrinsic viscosity of the resulting block copolymer decreases, which is not desirable.

The other polyester (II) constituting the conjugate fiber of the present invention contains terephthalic acid or 2,6-naphthalenedicarboxylic acid as a main acid component and an aliphatic α, ω-diol having 2 to 4 carbon atoms as a main component. In the polyester as a glycol component, an acid component and / or a glycol component other than the above may be copolymerized in an amount of 20 mol% or less with respect to the total acid component. Among them, polyethylene terephthalate is preferable from the viewpoint of its mechanical properties and cost.

The intrinsic viscosity of the polyester (II) is
Usually, 0.4 to 1.0 can be used. At this time, it is necessary to match it with the melt viscosity (under melt spinning temperature) of the polyester block copolymer which is one component of the composite fiber.
It is particularly preferable in terms of improving spinning stability.

When the composite fiber needs to be dyed, it can be dyed with a disperse dye, but the polyester block copolymer (I) part is deeply dyed and the polyester (II) part is difficult to dye. In addition, since the dyeing fastness tends to be low, it is preferable to copolymerize an ionic dye dyeing agent. For example, a 5-sodium sulfoisophthalic acid component and a 5-phosphonium sulfoisophthalic acid component are cationically dyeable. It can be illustrated as an agent. The dyeing agent is preferably copolymerized with both the polyester block copolymer (I) and the polyester (II), and the copolymerization amount thereof is 0.
5 to 5 mol%, particularly 1 to 3 mol% is preferable.

The conjugate fiber of the present invention is obtained by subjecting the polyester block copolymer (I) having the melting point of 150 to 220 ° C. described above and the polyester (II) to the conjugate spinning. In this case, the composite ratio of the former is 5 to 95%, preferably 10 to 90% (area ratio), and at least part of the former must be exposed on the fiber surface. If the polyester block copolymer (I) is not exposed on the fiber surface, the object of the present invention will not be achieved, which is not preferable. Examples of such a composite structure include side-by-side laminated fibers, core-sheath fibers, and eccentric core-sheath fibers that are eccentric.

The composite-spun yarn is then stretched and heat-set according to the purpose of use. For example, when utilizing the elastic recovery performance based on crimps, increasing the draw ratio is effective in improving the crimping degree, but when heat-treating this, it should be carried out under the condition that the crimp developability is not deteriorated. Is preferred. On the other hand, when it is used as a heat-adhesive fiber, it is often formed in the form of a non-woven fabric, so it is important to have good cardability in the card process, and the conditions for obtaining such a crimped state are set. There is a need.

Further, in the present invention, the cross-sectional shape of the composite fiber may vary in the fiber axis direction. For example, JP-A-54-42415 and JP-A-55-5.
No. 1809, a low-speed polymer discharged from a discharge hole having a large discharge area directly below a mouthpiece by discharging a polymer flow having two flow velocity differences through a pair of discharge holes having different discharge cross-sectional areas. High-speed polymer flow (polyester (II) flow) discharged from a discharge hole with a small discharge area is joined to the flow (polyester block copolymer flow) while colliding and vibrating, and then rapidly cooled. The composite fiber is particularly preferable because it has good elastic recovery performance.

[0026]

The polyester block copolymer (I) used in the conjugate fiber of the present invention is superior in light resistance, hydrolysis resistance, heat resistance, chlorine resistance, etc. to conventional elastic polymers. Since they are excellent, the composite fiber of the present invention can be developed into various applications by utilizing these characteristics.

For example, the side-by-side type composite fiber has excellent elastic recovery performance based on crimping, and has excellent durability such as light resistance, hydrolysis resistance and chlorine resistance.

When it is used as a heat-adhesive fiber, the polyester block copolymer is excellent in thermal oxidation resistance, so that heat deterioration, which has been a problem in the conventional heat-adhesion treatment in air, occurs. Difficult, heat bonding at high temperature is possible. Therefore, there is a feature that the heat resistance of the obtained fiber structure (for example, settling resistance at high temperature) is improved. Moreover, since the heat-adhesive component is polyester, it has good adhesiveness with polyester fibers such as polyethylene terephthalate and is suitable for obtaining a fiber structure excellent in shape retention and elastic recovery performance.

[0029]

The present invention will be described in more detail with reference to the following examples. The intrinsic viscosity is 3 in orthochlorophenol.
It was measured at 5 ° C.

[0030]

Example 1 Synthesis of Polyester Block Copolymer Dimethyl isophthalate and tetrabutylphosphonium 5
-Transesterification of dimethyl sulfoisophthalate (4 mol% with respect to dimethylisophthalate) with 1,10-decanediol and ethylene glycol using titanium tetrabutoxide (40 mmol% with respect to dimethylisophthalate) as a catalyst. After that, it was polymerized by a conventional method at 260 ° C. in a high vacuum to obtain a polyester (A ′) having an intrinsic viscosity of 1.05. When the copolymerization ratio of the glycol component was measured by gas chromatography after hydrolysis of the obtained polyester, it was 1,10-decanediol: ethylene glycol = 81: 19 (molar ratio).

On the other hand, dimethyl terephthalate and tetramethylene glycol were transesterified in the same manner as above using titanium tetrabutoxide (40 milmol% relative to dimethyl terephthalate) as a catalyst, and then polymerized to give an intrinsic viscosity of 0.91. A polyester having a melting point of 225 ° C. (high melting point polyester (B ′)) was obtained.

Next, 35 parts by weight of the polyester (B ') is melted at 250 ° C, 65 parts by weight of the polyester (A') is added, and the mixture is stirred and reacted at 250 ° C for 40 minutes under a high vacuum of 1 mmHg or less, When the inside became slightly transparent, phosphorous acid (1.5 mol times relative to titanium) was added.

The block copolymer thus obtained had an intrinsic viscosity of 1.10 and a melting point of 193 ° C. (measured with a differential assessment calorimeter at a heating rate of 20 ° C./min to obtain an endothermic peak temperature). Met.

Synthesis of aromatic polyester dimethyl terephthalate, tetrabutylphosphonium
Dimethyl 5-sulfoisophthalate (4 mol% based on dimethylisophthalate) and ethylene glycol are subjected to transesterification reaction using calcium acetate as a catalyst to distill almost theoretical amount of methanol, and then trimethyl phosphate is added for further oxidation. Add antimony and gradually reduce the pressure to 28
A polycondensation reaction was carried out at 5 ° C. to obtain a polyethylene terephthalate copolymer having an intrinsic viscosity of 0.62.

Manufacture of Composite Fiber The block copolymer and aromatic polyester obtained above were fed to each extruder of a composite fiber spinning machine having two screw type extruders, and a laminated composite fiber was prepared by a conventional method. Obtained.
This composite fiber was stretched 4.1 times using a heating roller at 80 ° C. and subjected to relaxation heat treatment at 160 ° C. This composite yarn was a crimped yarn in which the block copolymer and the aromatic polyester were present in an area ratio of about 1: 1.

When this yarn was knitted, a knitted fabric with good stretchability was obtained. This knitted fabric is treated with a cationic dye S at 120 ° C.
uK Navy Blve S-2GL (Sumitomo Chemical Co., Ltd.)
When it was dyed so as to have a concentration of 1% owf, the bath color almost disappeared and it was dyed well. Then, when the light resistance of this dyed product at 60 ° C. was measured with a xenon tester, it showed a light resistance of about grade 4 (JIS L-0843 blue scale). At this time, the elastic recovery performance was not deteriorated, and even when the knitted fabric was stretched, no white portion was observed.

[0037]

Example 2 Synthesis of Block Copolymer Dimethylisophthalate, 1,10 decanedicarboxylic acid (20 mol% based on the acid component), 1,6 hexanediol, dibutyltin diacetate catalyst (80 mmol based on the dicarboxylic acid component). %) To remove methanol and water, and then polycondensate under reduced pressure at 260 ° C.
A polyester (A ') having an intrinsic viscosity of 0.90 was obtained.

60 parts by weight of this polyester (A ') and 40 parts by weight of the same polyester (B') as used in Example 1 were stirred at 250 ° C. under a high vacuum of 1 mmHg or less, and after 20 minutes the inside became transparent. After a lapse of 5 minutes, phosphoric acid was added and stirred so that the number of phosphorus atoms was twice the number of tin atoms + the number of titanium atoms. The obtained polyester block copolymer has an intrinsic viscosity of 0.95 and a melting point of 185.
It was ℃.

Synthesis of Aromatic Polyester Polyethylene terephthalate having an intrinsic viscosity of 0.60 was obtained from dimethyl terephthalate and ethylene glycol in the same manner as in Example 1.

Manufacture of composite fiber Using the same spinning machine as in Example 1, a core-sheath composite fiber having the above block copolymer as a sheath and an aromatic polyester as a core was obtained. This core / sheath area composite ratio was about 50/50, and the core was eccentric. This fiber was drawn 4.0 times, cut into a fiber length of 64 mm, and then heat-treated at 140 ° C. to develop crimp. The single yarn fineness of the obtained fiber was 6 denier.

40% by weight of this composite fiber and 60% by weight of a hollow section polyethylene terephthalate short fiber having a fiber length of 64 mm and a normal single yarn fineness of 6 denier were mixed with a card to form a web. The resulting webs are then overlaid to a thickness of 5 cm and a density of 0.035 g / cm ³ and 220
A cushion material was obtained by heat treatment at 10 ° C. for 10 minutes. The obtained cushioning material was almost uncolored, white and highly elastic.

This cushioning material was compressed at 70 ° C. until the thickness became half, and after 30 minutes, it was restored to 80% when the bulk recovery property was measured at room temperature by removing the load.

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Claims (1)

[Claims] 1. A phthalic acid compound as a main acid component having 6 to 6 carbon atoms.
Polyester segment (A) containing 12 aliphatic α, ω-diols as the main glycol component, and aliphatic α, ω containing 2-4 carbon atoms containing the aromatic dicarboxylic acid as the main acid component
-A diol or a polyester segment (B) containing 1,4-cyclohexanedimethanol as a main glycol component and satisfying the following (a) and (b):
Polyester block copolymer (I) having a melting point of 150 to 220 ° C. and (a) a component constituting the polyester segment (A) are polycondensed to obtain a polyester having an intrinsic viscosity of 0.4 or more, and the melting point is 50 ° C. Less than or amorphous, (b) having a melting point of 180 ° C. or more when a polyester constituting the polyester segment (B) is polycondensed into a polyester having an intrinsic viscosity of 0.4 or more, terephthalic acid or 1. A composite fiber comprising a polyester (II) containing 2,6-naphthalenedicarboxylic acid as a main acid component and an aliphatic α, ω-diol having 2 to 4 carbon atoms as a main glycol component, the polyester block copolymer being a polyester fiber. (I) is 5 to 95 area% of the cross section of the composite fiber
And at least a part thereof is exposed on the surface of the fiber.