JP2008297683A - Conjugated fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conjugated fiber which is optimal for uses such as swimming suits and underwear, has excellent anti-transparency in white/light-colored fiber states, and can brilliantly be dyed, when dyed. <P>SOLUTION: This conjugated fiber comprise a thermoplastic resin layer A and a thermoplastic resin layer B containing a white pigment having a particle diameter of 0.2-1 μm in an amount of 2-10%, wherein the component A is bipartited by the component B in the cross section of the fiber, and the component A is partially exposed on both the surfaces of the divided fiber portions. The white pigment is preferably titanium dioxide, and it is preferable that a fluorescent brighter is contained in an amount of 0.01-0.05% in the component B. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thermoplastic synthetic fiber that is optimal for apparel applications.

  Synthetic fibers are superior to natural fibers in color development, dyeing fastness, strength, and processing versatility. For this reason, it is used in all clothing fields such as sports, ladies and gentlemen.

  By the way, the synthetic resin which is the raw material of the synthetic fiber is colorless and transparent. Therefore, if synthetic resin is used as it is, it becomes a transparent thread. Such yarns are not suitable for clothing applications, and ordinary synthetic fibers for clothing have titanium oxide particles added as a matting agent in the raw synthetic resin.

  Adding titanium oxide to synthetic fibers has long been a common technique. Even if there is no description about the addition of titanium oxide in the patent specification etc., the synthetic fiber contains titanium oxide unless specifically stated that “no titanium oxide is added”. It is common sense to think.

In general, polyamide fibers and polyester fibers that are often used for clothing contain more than 1% of titanium oxide. Many garments are used by dyeing fibers or cloths, and such an amount of titanium oxide added has sufficient shielding properties and is suitable for garments.
However, since white fabrics and light-colored fabrics that are not dyed are easy to see through and have a drawback that they can be seen through when they are wetted with water, in the sports clothing field such as swimwear, a fabric that is not transparent even in white or light-colored has been desired. .

  Conventionally, in order to improve such defects, a method has been proposed in which a synthetic polymer is mixed with a matting agent such as titanium oxide in a larger amount than usual to make the synthetic fibers opaque. However, when a large amount of matting agent is added to the synthetic resin, defects such as a decrease in spinning operability, a decrease in yarn physical properties such as strength, and a remarkable wear of mechanical parts during weaving and knitting are noticeable. Therefore, a composite fiber composed of a component containing a large amount of a matting agent and a normal synthetic resin component (which naturally also contains a small amount of titanium oxide) has been proposed. However, the fabrics obtained by these methods were not satisfactory in the see-through preventing property due to insufficient hiding power.

  On the other hand, when the white and non-translucent yarn is dyed, color development is deteriorated due to the effect of the added matting agent. This is a natural result in a sense, but there is a demand in the market for a thread that is excellent in the effect of preventing see-through even if it is white, and that vividly colors when dyed. Therefore, as disclosed in Patent Document 2, a fiber in which an opaque component and a transparent component are combined has been proposed, but the balance between opacity (prevention of see-through) and color developability has not been sufficient.

JP-A-8-60485 JP-A-5-247723

  The present invention has been made in view of such a current situation, and an object of the present invention is to obtain a fiber having an excellent effect of preventing see-through even in white / light color and having a vivid coloring property when dyed.

  That is, the present invention comprises a thermoplastic resin layer (A) and a thermoplastic resin layer (B) containing 2 to 10% (weight%) of a white pigment having a particle diameter of 0.2 to 1 μm, and one fiber cross section is provided. The main purpose is a composite fiber having a shape in which the A component is divided into two by the B component.

According to the present invention, even if the color is white / light, it is excellent in the effect of preventing see-through, and if it is dyed, a fiber having vivid color developability can be obtained.

  Hereinafter, the present invention will be described in detail. The thermoplastic resin (polymer) referred to in the present invention means all polymers having fiber-forming ability that can be synthesized by a polymerization reaction. Specifically, nylon 6, nylon 66, nylon 12, polyamides such as poly-p-phenylene terephthalamide, poly-m-phenylene isophthalamide, polyesters such as polyethylene terephthalate, polytrimethylene terephthalate, polylactic acid, Examples thereof include polyolefins such as polyethylene and polypropylene, and polyacryls such as polyacrylonitrile. Of course, it is not limited to these, and other types of polymers can be used. Each polymer is not limited to a homopolymer, and may be a blend, a copolymer, or the like.

  Among these polymers, nylon 6, polyethylene terephthalate, and polytrimethylene terephthalate are most widely used. The present invention can suitably use these polymers. Of these, the use of polyester is particularly preferred.

  In this invention, although the said polymer is used as a raw material of composite fiber, A and B2 component may be the same polymer or different polymers. However, when different polymers are combined, delamination between layers may occur depending on the combination of polymers, leading to generation of defective products such as yarn breakage and fluffing. Therefore, it is preferable that the A and B2 components are the same polymer.

The B component of the conjugate fiber of the present invention needs to contain a specific amount of a white pigment having a specific particle size.
Specifically, it is necessary to contain 2% to 10% (% by weight) of a white pigment having an average particle diameter of 0.2 μm to 1 μm.
If the average particle size is smaller than this, the shielding effect is not sufficient. On the other hand, if the average particle size is large, irregularities on the fiber surface become conspicuous, and wear of parts such as a spinning machine and a processing machine is accelerated.

  On the other hand, when the added amount of the white pigment is less than 2% in the B component, the intended shielding effect cannot be obtained. If the addition amount exceeds 10%, the above-mentioned troubles during spinning frequently occur.

In consideration of the balance between see-through spinning performance and spinning operability / post-processability, the average particle size of the white pigment used is preferably 0.2 μm to 1 μm, more preferably 0.2 μm to 0.5 μm.
For the same reason, the addition amount of the white pigment in the component B is preferably 2% to 10%, more preferably 3% to 8%.

  Examples of white pigments include titanium oxide, zinc oxide, magnesium oxide, aluminum oxide, zirconium oxide, calcium oxide, magnesium oxide, barium sulfate, and silica. Of these, titanium oxide is most preferably used.

  There is no restriction | limiting in particular in the addition method of a white pigment. The most commonly used method is to mix a master chip to which a white pigment has been added at a high concentration in advance with a normal chip and spin it. As described above, even a “normal chip” contains a small amount of white pigment.

  In the present invention, it is essential that the B component contains a specific amount of a white pigment having a specific particle diameter, but it is preferable that a small amount of white pigment is also contained in the A component. This is also for improving the anti-slipping property and the color developing property, and also improving the operability and the passability of the subsequent process. The white pigment in component A is preferably the same as that in component B. In the component A, the addition amount is preferably 0.01 to 1.5%, more preferably 0.2 to 1.0%.

  In the present invention, it is preferable to add a fluorescent brightening agent to the polymer of component B. The use of a fluorescent brightening agent is preferable because it is more excellent in light resistance and dyeing fastness than whitening by post-dying.

  The fluorescent whitening agent as used herein means an original fluorescent whitening agent that is added to the synthetic polymer at the time of fiber production, and must be one that does not hinder spinnability and stretchability. Specific examples include stilbene fluorescent brighteners, imidazole fluorescent brighteners, imidazolone fluorescent brighteners, triazole fluorescent brighteners, thiazole fluorescent brighteners, and oxazole fluorescent brighteners. it can.

  Although the content of the optical brightener is arbitrary, it is necessary to add at least 0.01% by weight in order to obtain a white effect. On the other hand, if there is a large amount of fluorescent whitening agent, self-quenching occurs and the whitening effect is diminished, so an addition amount of 0.05% by weight is sufficient. In addition, the weight% here is a thing in B component.

  There is no particular limitation on the method of adding the optical brightener. Often used is a method of mixing a master chip to which a fluorescent whitening agent has been added at a high concentration in advance and a normal chip, and spinning them. There is also a method in which a chip and a fluorescent brightening agent are mixed and used for spinning.

  In addition, when adding a fluorescent brightening agent, it is preferable not to add it to A component only as B component. This is because component A contributes to the color developability of the fiber, but if a brightening agent is included, the color development of other colors may be suppressed.

  In addition, it is optional to add various additives for the purpose of improving fiber properties and functionalization. Examples of such additives include antistatic agents, light-proofing agents, heat-resistant agents, and flame retardants. Further, ordinary polymers are slightly colored due to the presence of a metal component which is a polymerization catalyst. In order to reduce the coloring caused by such a catalyst, a small amount of dye / pigment may be added. These additives may be added to either component A or component B, or may be added to both components.

  There is no particular limitation on the cross-sectional shape of the fiber of the present invention. Generally, round cross-sections are used. However, by changing the shape such as polygonal shape or flat shape, the reflection state of light on the fiber surface is changed, thereby improving the shielding performance.

In order to obtain the effects of the present invention, the composite structure of the two polymer components A and B needs to have a specific shape. Specifically, it is necessary to have a shape in which the A component is divided into two parts by the B component containing the white pigment, and all the A components are partially exposed on the fiber surface.
Examples of such shapes include the examples shown in FIGS. 1 and 2. Among them, the so-called “hamburger type” as shown in FIG. 1 is preferable in terms of both effect and cost.

  Here, all of the A component is partially exposed on the fiber surface because the A component is not completely included in the B component, for example, A-B-A is concentrically formed. It means that the structure is not arranged.

  The ratio of both components A and B in the composite fiber is preferably 1: 1 to 4: 1. More preferably, it is 1: 1 to 3: 1. Within this range, the balance between shielding properties and coloring properties is good. In the ratio here, the A component divided into two is calculated by adding up the divided portions.

  The composite fiber of the present invention can significantly suppress the exposure of the white pigment to the fiber surface as compared with, for example, a fiber composed of the component B alone. The white pigment exposed on the fiber surface wears parts of various devices and machines in the spinning process and the subsequent processes. Since the side effect of such a white pigment can be minimized in the conjugate fiber of the present application, spinning operability and post-process passability are improved.

  There is no particular limitation on the spinning method for obtaining the product of the present invention. Known methods can be used as appropriate. The fiber may be in the form of either a filament or a staple, and is made according to the application.

  Furthermore, the fiber obtained by normal spinning is appropriately twisted (particularly strong twist), or part of the surface of the fiber is dissolved with an alkaline solution after being made into a fabric, so that the light reflection on the fiber surface is improved. It can also be changed to improve the shielding performance (through prevention effect).

  The conjugate fiber of the present invention may be used alone or as one component of a mixed yarn. For example, it can be used for the outer yarn of the covering yarn.

  Moreover, when making into a fabric, you may mix and use with another fiber. Specifically, there are methods such as knitting and weaving. When mixed with other fibers, it is necessary to take into account that the shielding performance of the product of the present invention is offset by using other fibers.

  The fiber of the present invention can be used as “white fiber (fabric)” as it is without being dyed, but may be dyed with a small amount of dye to be “light fiber (fabric)”. Of course, even if it is a light color, the shielding performance can be exhibited.

  Further, when the fiber of the present invention is subjected to normal dyeing, sufficient color developability is exhibited. Dyeing is appropriately selected according to the polymer used as a raw material, and dyeing is performed by a known appropriate method. Even a dyed fabric has sufficient shielding performance.

The fabric made of the fiber of the present invention is suitably used for sports applications such as swimwear. It does not show through even when wet. In addition, since it has excellent color development, it can be made into a design and artistic pattern.
Furthermore, pants (trousers) and outerwear made of the fibers of the present invention have the effect that the color pattern of the clothing underneath is inconspicuous. This means that the color of the garment itself can be made to stand out, so that it has the effect of being excellent in design.
Furthermore, it is possible to minimize the wear of equipment and machine parts by the white pigment.

Hereinafter, the present invention will be specifically described by way of examples. The composite fiber was produced by the following procedure.
(Production example)
A master chip (M1) having an average particle size of 0.3 μm and a titanium oxide content of 20% was produced using regular PET resin (containing 0.01% by weight of titanium oxide). Also, a regular PET master chip (M2) having a fluorescent brightening agent content of 10% was produced. A chip blend obtained by appropriately mixing M1, M2 and the above-described regular PET resin was used as a spinning raw material (component B). A 56 dtex / 36f composite fiber having a cross-sectional shape as shown in FIG. 1 was produced using this as a B component and regular PET containing 0.4% by weight of titanium oxide as an A component. The ratio of component A to component B was 2: 1.

(Evaluation of spinning operability)
In the above-mentioned fiber manufacturing process, the occurrence of yarn breakage during production, the ratio of defective products such as single yarn breakage, and other troubles were observed.

(Evaluation of shielding properties)
The fiber was a cylinder. The cylindrical knitting was scoured and dried to prepare a measurement sample having a length of 15 cm. This was placed on a commercially available plastic underlay, and a transparent acrylic plate (15 cm × 15 cm; thickness 1 cm) was placed thereon. It was observed from the top of the acrylic plate to evaluate how much the pattern and characters under the sample can be recognized. Thereafter, the acrylic plate was once removed, 5 mL of distilled water was dropped on the sample, and then the acrylic plate was placed again, and the same evaluation was performed.

(Evaluation of abrasion)
A 5 kg drawn yarn was false twisted. At this time, thread breakage and the state of wear of parts of the processing apparatus were confirmed.

(Evaluation of dyeability)
The same cylindrical knitted sample used for the shielding evaluation was used. The sample was dyed by a conventional method using a polyester disperse dye. The state of staining was evaluated visually. If necessary, a cylindrical knitted sample made of regular PET fibers was compared with a dyed sample under the same conditions.

<Example>
According to the above production example, three kinds of raw materials having a fluorescent whitening agent content of 0.04% by weight and a titanium oxide content of 3, 6% and 8% by weight were prepared to produce yarns. In any case, no trouble was observed during production, and the obtained fiber had satisfactory physical properties. When the shielding properties of these samples were evaluated, all of them had sufficient shielding performance. In the wear evaluation, no problem was found. In the dyeing evaluation, each of three colors of red, blue, and yellow was dyed.

<Comparative Example 1>
In the production example, titanium oxide having an average particle diameter of 0.01 μm was used when producing the master chip M1. The other master chips were set to the same conditions as in the production example. The ratio of the chips was adjusted so that the component B contained 5% by weight of titanium oxide and 0.03% by weight of the brightening agent. Using this, a yarn was produced according to the production example. No particular problems were found during manufacturing. A cylindrical knitted sample was produced from the obtained yarn. Shielding property evaluation was performed with the cylindrical knitted sample. When the sample was dry, large letters and patterns were slightly visible, and other letters and patterns could hardly be confirmed. However, when the sample was wet, the pattern was clearly confirmed. There was no problem in the wear evaluation.
Dyeability was not particularly problematic.

<Comparative example 2>
In the production example, titanium oxide having an average particle diameter of 5 μm was used when producing the master chip M1. The other master chips were set to the same conditions as in the production example. The ratio of the chips was adjusted so that the component B contained 5% by weight of titanium oxide and 0.03% by weight of the brightening agent. Using this, a yarn was produced according to the production example. The increase in filtration pressure became prominent during production, and the target 10 kg fiber could not be produced. Also, some single yarn breakage was observed. Furthermore, some yarns showed knots. A cylindrical knitted sample was produced from the obtained yarn. Shielding property evaluation was performed with the cylindrical knitted sample. When the sample was dry, large letters and patterns were slightly visible, and other letters and patterns could hardly be confirmed. The same was true when the sample was wet.
In the abrasion evaluation, single yarn breakage was observed. In the staining evaluation, some staining spots were seen.

<Comparative Example 3>
The master chip shown in the production example was used. The ratio of the chips was adjusted so that the component B contained 1% by weight of titanium oxide and 0.03% by weight of the brightening agent. Using this, a yarn was produced according to the production example. No particular problems were found during manufacturing. A cylindrical knitted sample was produced from the obtained yarn. When the sample was dry, characters and patterns of about 12 points were slightly visible. When the sample was wet, the pattern and some characters were clearly confirmed. There was no problem in the wear evaluation.
There was no particular problem in dyeing evaluation.

<Comparative Example 4>
The master chip shown in the production example was used. The ratio of the chips was adjusted so that B component contained 12% titanium oxide and 0.03% fluorescent brightener. Using this, a yarn was produced according to the production example. The increase in filtration pressure became prominent during production, and the target 10 kg fiber could not be produced. Also, some single yarn breakage was observed. Furthermore, some yarns showed knots. A cylindrical knitted sample was produced from the obtained yarn. Shielding property evaluation was performed with the cylindrical knitted sample. When the sample was dry, large letters and patterns were slightly visible, and other letters and patterns could hardly be confirmed. The same was true when the sample was wet.
In the abrasion evaluation, single yarn breakage was observed. In the staining evaluation, some staining spots were seen.

<Comparative Example 5>
The master chip shown in the production example was used. The ratio of the chips was adjusted so that the component B contained 6% by weight of titanium oxide and 0.03% by weight of the brightening agent. Using this, a yarn was produced according to the production example. However, a base whose composite shape is a side-by-side type as shown in FIG. 3 was used. No particular problems were found during manufacturing. A cylindrical knitted sample was produced from the obtained yarn. Shielding property evaluation was performed with the cylindrical knitted sample. When the sample was dry, the letters and patterns of 12 points were slightly visible. When the sample was wet, the pattern and some characters were clearly confirmed.
In the abrasion evaluation, single yarn breakage was observed. Some guide rollers also showed significant wear. In the dyeing evaluation, the dyeing methods of the A component and the B component were clearly different. For this reason, the fabric after dyeing was very bad in appearance.

  The fibers of the present invention are white / lightly colored but have excellent shielding properties and, when dyed, also have excellent color development properties, and are particularly useful for apparel applications such as sportswear.

An example of the most preferable cross-sectional shape of the fiber of the present invention An example of the cross-sectional shape of the fiber of the present invention Example of cross-sectional shape of fiber outside the present invention (side-by-side)

Explanation of symbols

A Thermoplastic resin component A ₁ Thermoplastic resin component A ₂ Thermoplastic resin component B Thermoplastic resin component containing a specific amount of white pigment

Claims (6)

It consists of a thermoplastic resin layer (A) and a thermoplastic resin layer (B) containing 2 to 10% of a white pigment having a particle size of 0.2 to 1 μm, and the A component is divided into two by one B component in the fiber cross section. And a composite fiber characterized in that all components A are partially exposed on the fiber surface. The composite fiber according to claim 1, wherein the white pigment is titanium oxide. The composite fiber according to claim 1 or 2, wherein the component B contains 0.01 to 0.05% of a fluorescent brightening agent. The composite fiber according to any one of claims 1 to 3, wherein the thermoplastic resin of component A and component B is polyester. The composite fiber according to claims 1 to 4, wherein the component A contains a white pigment of 1.0% or less. The composite fiber according to claim 1, wherein the composite ratio of the A component and the B component is 1: 1 to 4: 1.

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