JPH11247027A - Extremely fine fiber and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an extremely fine fiber widely improved in light resistance and capable of coloring in a high concentration, and to provide a method for producing the same. SOLUTION: This extremely fine fiber is obtained by unevenly distributing an ultraviolet-rays absorbing agent at the surface of the extremely fine fiber having <=1 d monofilament thickness, and the contained concentration of the ultraviolet rays-absorbing agent is in a range of 3-30 wt.% based on the resin weight of the surface layer part. The method for producing such extremely fine fiber comprises using a polymer containing 3-30 wt.% ultraviolet rays- absorbing agent as a sheath component and combining it with such a core component that the ultraviolet rays-absorbing agent in the sheath component becomes >=1.5 fold that in the total extremely fine fiber followed by spinning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrafine fiber having not only excellent light resistance but also excellent performance capable of being colored at a high concentration, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, demands for textile products in terms of both sensitivity and function have been increasing. There are demands for the sensibility side such as improvement of flexibility, improvement of smoothness of surface touch, and improvement of surface quality. One of the effective means for these is to reduce the fineness of single yarn, especially single yarn. Fiber products using ultrafine fibers having a fineness of 1d or less are widely used.

On the other hand, one of the major requirements in terms of function is to improve light resistance. In other words, there is a demand for reducing discoloration and decrease in strength due to light regardless of the use of clothing and materials. This is a long-standing issue, with a single yarn fineness of 1
It is approaching a fairly satisfactory level for normal level yarns above d.

[0004]

However, the light fastness of a fiber is closely related to the single-fiber fineness of the fiber. When the single-fiber fineness is 1 d or less, particularly 0.5 d or less, the light fastness rapidly decreases. In such ultrafine fibers, effective means for improving lightfastness that is effective for fibers having a normal level of thickness has little effect, and to date, no ultrafine fibers with excellent lightfastness have been obtained. It is. Under such circumstances, there has been a strong demand for ultrafine fibers having excellent light resistance and satisfying the requirements of both sensitivity and function.

[0005] The ultrafine fibers contain an ultraviolet absorber,
Attempts to improve its lightfastness have been made, but have had little effect. The reason is as follows. That is, the UV absorber protects the polymer and the dye located somewhat inside from the surface, but has little effect on protecting the dye existing near the surface. The finer the fiber, the greater the ratio of the surface vicinity to the whole, and as a result, the effect of the ultraviolet absorbent decreases.

In order to improve the effect of the ultraviolet absorber,
It seems that the concentration of ultraviolet absorption may simply be increased, but such fibers have insufficient strength or poor passability in the subsequent process,
There is a limit in the concentration of the ultraviolet absorber, and sufficient light resistance has not been obtained.

[0007] In view of the background of the prior art, the present invention provides
It is an object of the present invention to provide an ultrafine fiber which significantly improves the light fastness of the ultrafine fiber and has excellent performance capable of being colored at a high concentration, and a method for producing the same.

[0008]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the ultrafine fiber of the present invention is a fiber in which the ultraviolet absorbent is unevenly distributed on the surface of the ultrafine fiber having a single-fiber fineness of 1 d or less, and the concentration of the ultraviolet absorbent is less than the resin of the surface layer portion. It is characterized in that it is in the range of 3 to 30% by weight with respect to the weight. In the production method of such an ultrafine fiber, when producing an ultrafine core-sheath composite fiber having a single yarn fineness of 1d or less, the sheath component is used. And a polymer containing 3 to 30% by weight of an ultraviolet absorber, and the ultraviolet content of the sheath component is 1.
The composite spinning is performed by combining a core component that is 5 times or more, and after forming a ternary composite fiber composed of a sea component, a sheath component and a core component, the sea component is removed. To produce an ultrafine core-sheath conjugate fiber having a single yarn fineness of 1 d or less, an ultraviolet absorber is used as the sheath component in an amount of 3 to 3
A polymer containing 0% by weight of the core component, and a polymer in which the concentration of ultraviolet light contained in the sheath component is 1.5 times or more the concentration of the ultraviolet absorbent contained in the whole ultrafine fiber, and The sea component is extracted under the condition that the sea component is dissolved but the sheath component, the core component and the ultraviolet absorber are not substantially dissolved.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention addresses this problem, namely,
After eagerly examining ultrafine fibers that have excellent performance that can be colored at a high concentration while significantly improving the light resistance of the ultrafine fibers, if the UV absorber is localized at an extremely high concentration near the surface of the fiber, It has been clarified that both the light resistance and the high-concentration coloring function can be greatly improved without lowering the physical properties of the fiber, and the above problems can be solved at once.

That is, if the deterioration reaction of fibers and dyes by light progresses preferentially on the surface of the fiber, and if light can be shielded on the surface of the fiber, not only the ultraviolet absorber is not necessarily required inside, but also the fiber Focusing on adverse effects on light fastness, they found that if an ultraviolet absorber was selectively included at a high concentration on the surface of ultrafine fibers, the light fastness could be improved without impairing the physical properties and processability of the fibers. Surprisingly, such microfibers have the effect of being able to achieve the effect of being able to achieve dark-colored dyeing, brilliantly reversing the fact that dark-colored dyeing, which is the greatest drawback of microfibers, cannot be performed. It is.

The present invention provides an ultrafine fiber containing an ultraviolet absorbent and having a single-fiber fineness of 1d or less, wherein the concentration of the ultraviolet absorbent at a depth within 0.5 μm from the surface of the ultrafine fiber is such that It is in the range of 3 to 30% by weight, preferably 5 to 30% by weight, more preferably 10 to 30% by weight, and more preferably, the concentration is the concentration of the ultraviolet absorbent in the whole fiber. Is 1.5 times or more.

When the concentration of the ultraviolet absorbent in the vicinity of the surface is less than 3% by weight, there is no effect on the improvement of light resistance.
Bleed-out of UV absorber if it exceeds 10% by weight,
Problems such as a decrease in fiber physical properties occur. Furthermore, when the ultraviolet absorber content in the vicinity of the surface is less than 1.5 times the ultraviolet content of the whole fiber, uneven distribution of the ultraviolet absorber on the surface portion is insufficient, and light resistance and physical properties, Further, there is a tendency that the dark color dyeing function cannot be satisfied.

Conventionally, the concentration of an ultraviolet absorbent in a fiber is at most about 1% by weight, and the concentration of the ultraviolet absorbent of the present invention is 3 to 30% by weight based on the weight of the resin on the surface. The density of% is a high-density area that has never been considered before. Further, the present invention exerts an effect on ultrafine fibers having a single yarn fineness of 1d or less, and more preferably exerts an effect particularly on fibers having a single yarn fineness of 0.5d or less.

In one preferred embodiment of the present invention, the concentration of the ultraviolet absorbent at a depth of 1.0 μm or more from the surface of the ultrafine fiber is 1% by weight or less. It is not clear why the lower the concentration is, the better the light resistance is, but it is thought that the ultraviolet absorber promotes the deterioration of the fiber or dye by the catalytic action in the center of the fiber.

The present invention relates to an ultrafine fiber containing an ultraviolet absorber and having a single yarn fineness of 1d or less, wherein the ultraviolet absorber is laminated on the fiber surface in the form of a resin mixture;
It is one that is firmly laminated on the surface of ultrafine fibers. In a typical structure, the ultrafine fibers are core-sheath composite fibers.

In such a core-sheath type composite fiber, the content of the ultraviolet absorbent in the sheath is 3 to 30% by weight based on the weight of the resin in the sheath, and the content of the average ultraviolet absorbent in the whole fiber is It is characterized by being 1.5 times or more.

With such a core-sheath structure, the ultraviolet absorber can be controlled and unevenly distributed in the vicinity of the fiber surface, and the ultraviolet light is partially reflected at the interface between the core and the sheath. Thereby, the polymer and the dye inside the fiber are protected, and the light resistance and the color development can be greatly improved.

The concentration of the ultraviolet absorber in the sheath component is 3% by weight.
When the amount is less than the above, there is no effect of improving the light fastness and the deep color dyeing. When the amount exceeds 30% by weight, problems such as bleed out of the ultraviolet absorbent and deterioration of fiber properties occur.

Furthermore, when the concentration of the ultraviolet absorber in the sheath component is less than 1.5 times the ultraviolet concentration of the whole fiber, the localization of the ultraviolet absorber on the surface is insufficient, and the light resistance is poor. It is not possible to balance properties and physical properties, as well as deep color dyeing.

The ratio between the sheath and the core is not particularly limited.
The thickness of the sheath is preferably adjusted as appropriate in accordance with the concentration of the ultraviolet absorbent in the ultrafine fibers and the purpose and use of the fibers. That is, when the ultraviolet content of the sheath is high, or when the target light resistance level is not so high, the sheath can be adjusted to be thin, and the ultraviolet absorbent content of the sheath is low. In some cases or when the target level of lightfastness is relatively high, the thickness can be adjusted by increasing the thickness of the sheath.

The material of the ultrafine fibers of the present invention is not particularly limited, and polyolefins such as polypropylene and polyethylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, nylon 6, nylon 6,
Polyamides such as 6 and copolymers thereof, polyvinyl chloride, acrylic and acrylic copolymers can be used, but polyester is particularly preferably used.

The combination of the polymer of the core and the sheath is not particularly limited, and the core and the sheath may be the same polymer, a combination of different polymers, or a combination of the same polymer having different degrees of polymerization. I don't care.

The method for forming the ultrafine fibers is not particularly limited, and a usual spinning / drawing step may be employed, a superdraw method, or a method in which two or more types of components are spun and then separated and separated. Etc. can be adopted. In particular, when a method of dissolving and removing at least one component is used after spinning together two or more types of polymers having different solubilities, a space is formed between fibers,
A sheet having excellent flexibility can be obtained. As the sea component in such a case, for example, polyethylene, polystyrene, copolymerized polystyrene, polyester, copolymerized polyester and the like can be used.

The ultrafine fiber-forming polymer is not particularly limited. Polyamide such as nylon 6, nylon 6,6, polyethylene terephthalate, polyethylene terephthalate containing a copolymer component, polybutylene terephthalate, polyacrylonitrile or the like may be used alone or as a mixture. Can be used. As the form of the ultrafine fiber, a hollow cross section, a triangular or Y-shaped irregular cross section, or a composite yarn of two or more polymers can be used in addition to a normal round cross section.

The ultraviolet absorbent of the present invention is not particularly limited.
Low molecular compounds, high molecular compounds, inorganic compounds, and the like can be used as appropriate. For example, as the low-molecular compound, benzophenone-based, benzotriazine-based, benzotriazole-based, and salicylic acid-based compounds can be used.
Polyamide, those copolymerized with polymers such as polyolefins, as inorganic compounds, titanium oxide, cerium oxide,
Zinc oxide, carbon black and the like can be used.

As a method for producing a polymer containing an ultraviolet absorber, for example, a method of adding an ultraviolet absorber at the time of polymerizing a polymer, a method of copolymerizing a monomer acting as an ultraviolet absorber, or a method of forming a polymer and then absorbing the ultraviolet light A method of kneading the agent or the like can be adopted.

In one preferred embodiment of the core-sheath type composite fiber, the concentration of the ultraviolet absorbent in the core is 1% by weight or less. This is because the concentration of the ultraviolet absorbent is 1% by weight. This is because extremely high light resistance can be obtained by the following. It is also possible to post-process the ultrafine fibers of the present invention to further contain an ultraviolet absorber.

In the method for producing the ultrafine fiber of the present invention, an ultraviolet absorber is used as a sheath component in an amount of 3 to 30% by weight, preferably 5 to 30% by weight, more preferably 5 to 30% by weight, based on the resin weight of the sheath component. Is a polymer containing 10 to 30% by weight, and combined with a core component such that the ultraviolet ray content of the sheath component is 1.5 times or more the ultraviolet ray absorber content of the whole ultrafine fiber. Is what you do.

According to this method, the concentration of the ultraviolet absorbent in the core and the sheath can be controlled with high precision, so that the ultraviolet absorbent of a desired concentration can be easily localized on the surface of the fiber. It is preferred.

As another manufacturing method, after forming a ternary composite fiber comprising a sea component, a sheath component and a core component, the sea component is removed to produce an ultrafine core-sheath composite fiber having a single yarn fineness of 1d or less. Can be adopted. Also in this case, as the sheath component, a polymer containing an ultraviolet absorber in an amount of 3 to 30% by weight, preferably 5 to 30% by weight, more preferably 10 to 30% by weight, based on the resin weight of the sheath component is used; A combination with a core component such that the ultraviolet content of the sheath component is 1.5 times or more the ultraviolet absorbent content of the entire microfiber, and the sea component dissolves, but the sheath component,
A method of extracting the sea component under a condition in which the core component and the ultraviolet absorber are not substantially dissolved can be adopted. According to this method, it is possible to stably produce the ultrafine core-sheath conjugate fiber, and at the same time, it is possible to prevent the ultraviolet absorber contained in the fiber from falling off.

In this case, the sea component, the sheath component, and the core component are not particularly limited. As the sea component, polyethylene, polystyrene, copolymerized polystyrene, polyester, copolymerized polyester, and the like can be used. For example, polyamides such as nylon 6, nylon 6,6, etc., polyethylene terephthalate, polyethylene terephthalate containing a copolymer component, polybutylene terephthalate, polyacrylonitrile and the like can be used alone or as a mixture.

Further, one of the preferable embodiments of the production method is as follows.
One is that the sea component is mainly composed of a polymer soluble in an aqueous solvent, and the ultraviolet absorber does not substantially dissolve,
For the sea component, a method of extracting the sea component with a soluble aqueous solvent can be employed.

The aqueous solvent refers to a solvent mainly composed of water, for example, water, an alkaline aqueous solution such as a sodium hydroxide aqueous solution or an ethylamine aqueous solution, an acidic aqueous solution such as an acetic acid aqueous solution or a sulfuric acid aqueous solution, an alcohol aqueous solution or a DMF aqueous solution. An aqueous solution of an organic substance, an aqueous solution of an inorganic substance such as an aqueous solution of sodium chloride, an aqueous solution of a surfactant such as an aqueous solution of sodium dodecyl sulfate, or the like can be used. In addition, these aqueous solvents can be mixed or heated.

As the polymer soluble in the above-mentioned aqueous solvent, for example, polyesters and copolymerized polyesters soluble in an alkaline aqueous solution, urethanized polyalkylene oxide, esterified polyalkylene oxide and the like can be used.

Further, when the fiber is subjected to a drawing treatment and / or a heat treatment before the step of removing the sea component,
Dropping of the ultraviolet absorber during removal of the sea component can be greatly reduced.

The stretching method is not particularly limited.
An ordinary roll stretching method can be employed.
The stretching ratio is preferably higher to prevent the ultraviolet absorber from falling off, but if it is too high, problems such as thread breakage occur, so the polymer to be used, the ultraviolet absorber, stretching conditions,
It is necessary to select appropriately depending on the sea component removal conditions, etc.,
Generally, conditions between 2 and 4 times are preferably used.
It is also possible to heat the yarn at the time of drawing, and as a method thereof, a hot roll, a hot pin, a hot plate, a hot liquid bath, steam, or the like can be used. Further, the crystallization method is not particularly limited, and thermal crystallization using hot air, hot water, steam, or the like can be used.

[0037]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Example 1 A core-sheath composite fiber was prepared using a base for a two-component core-sheath composite yarn. The compound conditions are as follows.

Core component: polyethylene terephthalate Sheath component: benzotriazole-based ultraviolet absorber
0% by weight dispersed polyethylene terephthalate Core / sheath ratio: core 50%, sheath 50% The ultrafine core / sheath composite fiber is stretched 3.5 times in a liquid bath at 80 ° C. to obtain a 0.3d ultrafine core / sheath composite fiber. I got After crimping the ultrafine fibers, they were cut to obtain raw cotton. The raw cotton was formed into a web using a cross wrapper, and further subjected to needle punching to obtain a nonwoven fabric. The nonwoven fabric was impregnated with a 10% by weight polyvinyl alcohol solution, then squeezed and dried. Thereafter, a prepolymer obtained from a mixed diol of polyethylene adipate and polybutylene adipate and p, p'-diphenylmethane diisocyanate, which had been separately prepared, was chain-extended with ethylene glycol. After impregnating with the solution and setting the amount of polyurethane to 35% by weight with respect to the weight of the nonwoven fabric, the polyurethane was coagulated in a wet method, and at the same time, the polyvinyl alcohol was removed. After immediately pressing and drying, the sheet was brushed. Dyeing with a disperse dye gave a leather-like sheet.

The obtained sheet-like material had an unprecedented deep color and excellent coloring properties. JIS L 084
The light fastness of this sheet was measured based on the two methods.
Further, the tensile strength of this fabric was measured. Table 1 shows the results
Shown in

Comparative Example 1 A single component yarn was spun using the same polyethylene terephthalate as used as the core component in Example 1, and stretched under the same conditions as in Example 2 to obtain a 0.3 d ultrafine fiber. .

A leather-like sheet was obtained in the same process as in Example 2 except that this fiber was used in place of the core-sheath ultrafine fiber. The obtained leather-like sheet had a whitish color unique to ultrafine fibers. Table 1 shows the light fastness and the tensile strength of the sheet material measured in the same manner as in Example 1.

Comparative Example 2 A single component yarn was spun using the same polyethylene terephthalate in which an ultraviolet absorber was dispersed as in the case of Example 1 as a sheath component, and stretched under the same conditions as in Example 1 to form a 0.1% yarn. 3
d was obtained.

A leather-like sheet was obtained in the same process as in Example 1 except that this fiber was used in place of the core-sheath ultrafine fiber. The obtained leather-like sheet had a whitish color unique to ultrafine fibers. Table 1 shows the light fastness and the tensile strength of the sheet material measured in the same manner as in Example 1.

Comparative Example 3 Instead of the sheath component used in Example 1, a single component yarn was spun using polyethylene terephthalate in which the same ultraviolet absorber was dispersed at 2.5% by weight under the same conditions as in Example 1. Drawing was performed to obtain 0.3 d of ultrafine fibers.

A leather-like sheet was obtained in the same process as in Example 1 except that this fiber was used in place of the core-sheath ultrafine fiber. The obtained leather-like sheet had a whitish color unique to ultrafine fibers. Table 1 shows the light fastness and the tensile strength of the sheet material measured in the same manner as in Example 1.

[0047]

[Table 1] As can be seen from Table 1, it is possible to obtain a leather-like sheet having excellent light resistance and coloring properties by using the ultrafine fibers of the present invention and the method for producing the same.

Example 2 Using a sea-island composite ferrule having an island component having a core-in-sheath structure, the following polymer was used as the polymer so that the ratio of the sea component: the sheath component: the core component was 20:20:60. To obtain a core-sheath type sea-island composite fiber having 14 islands. The sea-island composite fiber was drawn three times to obtain a multifilament yarn comprising 40 3.5d filaments.

Sea component: ethylene glycol as a diol, terephthalic acid as a dicarboxylic acid and 5 mol%
Mixture of sodium sulfoisophthalic acid (mixing molar ratio 9
Copolymerized polyester polymerized from 5: 5) Sheath component: 7% by weight of benzotriazole-based ultraviolet absorber
Dispersed polybutylene terephthalate Core component: polybutylene terephthalate The fiber is used as warp and weft to form a plain weave, which is treated in a 1% by weight aqueous sodium hydroxide solution at 95 ° C. for 30 minutes to obtain a single yarn fineness of 0.2 d. An ultrafine fiber woven fabric comprising the core-sheath ultrafine fibers was obtained. The ultrafine fiber fabric was dyed and washed with a jet dyeing machine by a conventional method using a disperse dye. The light-fastness and tearing strength of the obtained fabric were measured in the same manner as in Example 1 in which the fabric having excellent deep coloration, which was not found in fabrics using conventional ultrafine fibers, was obtained. Table 2 shows the results.

Comparative Example 4 A core-sheath ultrafine fiber having a single-fiber fineness of 0.2 d was prepared in the same manner as in Example 2 except that polybutylene terephthalate in which an ultraviolet absorber was dispersed at 0.5% by weight was used as a sheath component. An ultrafine fiber fabric was obtained, and dyed and washed in the same manner as in Example 3. The obtained fabric had a pastel whitish color peculiar to ultrafine fibers. The light fastness and tear strength of this fabric were measured in the same manner as in Example 1. Table 2 shows the results.

[0051]

[Table 2] As can be seen from Table 2, it is possible to obtain a leather-like sheet having excellent light resistance and coloring properties by using the ultrafine fiber of the present invention and the method for producing the same.

[0052]

According to the present invention, it is possible to provide excellent ultrafine fibers which are excellent not only in light resistance but also in physical properties of fibers and which are colored at a high concentration. Further, it is possible to stably produce such ultrafine fibers. Can be.

Claims (10)

[Claims] 1. A fiber in which an ultraviolet absorbent is unevenly distributed on the surface of an ultrafine fiber having a single yarn fineness of 1 d or less, and
An ultrafine fiber, wherein the concentration of the ultraviolet absorbent is in the range of 3 to 30% by weight based on the weight of the resin in the surface portion. 2. In the ultrafine fiber, 1.5 times or more of the average ultraviolet absorbent content is 0.5 μm from the surface of the fiber.
The ultrafine fiber according to claim 1, which is unevenly distributed at a depth of not more than m. 3. The ultrafine fiber according to claim 1, wherein the concentration of the ultraviolet absorbent at a depth of 1.0 μm or more from the surface of the ultrafine fiber is 1% by weight or less. 4. The ultrafine fiber according to claim 1, wherein the ultraviolet absorbent is laminated on the fiber surface in the form of a resin mixture. 5. The ultrafine fiber is a core-sheath type composite fiber,
The ultrafine fiber according to any one of claims 1 to 3, wherein an ultraviolet absorber is unevenly distributed in the sheath. 6. The ultrafine fiber according to claim 5, wherein the content of the ultraviolet absorbent in the core of the core-sheath type composite fiber is 1% by weight or less. 7. In producing an ultrafine core-sheath composite fiber having a single yarn fineness of 1d or less, an ultraviolet absorber is used as the sheath component.
Composite spinning using a polymer containing 30 to 30% by weight and combining with a core component such that the ultraviolet content of the sheath component is 1.5 times or more the ultraviolet absorbent content of the whole ultrafine fiber. A method for producing ultrafine fibers, characterized by comprising: 8. After forming a ternary composite fiber comprising a sea component, a sheath component and a core component, the sea component is removed to obtain a single yarn fineness of 1d.
In producing the following ultrafine core-sheath conjugate fiber, a polymer containing an ultraviolet absorber in an amount of 3 to 30% by weight is used as the sheath component, and the concentration of the ultraviolet ray contained in the sheath component is equal to the ultraviolet ray of the entire ultrafine fiber. The polymer used as the core component is 1.5 times or more the absorbent content, and the sea component is dissolved, but the sheath component, the core component and the ultraviolet absorbent are not substantially dissolved, A method for producing ultrafine fibers, comprising extracting the sea component. 9. The method according to claim 1, wherein the sea component is mainly composed of a polymer soluble in an aqueous solvent, and the ultraviolet absorber is substantially insoluble, but the sea component is extracted with an aqueous solvent that is soluble. The method for producing ultrafine fibers according to claim 8, wherein 10. An ultraviolet absorbent content of 1 to said core component.
The method for producing ultrafine fibers according to any one of claims 7 to 9, wherein a polymer contained in a range of not more than% by weight is used.