JP5378658B2 - Thermoplastic synthetic fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide white/light-colored fibers optimal for uses such as swimming suits and underwear and having excellent anti-transparency at a level free from a practical problem on spinning operability and post-process passableness. <P>SOLUTION: The synthetic fibers comprise a thermoplastic resin, such as a polyethylene terephthalate, containing 2 to 10 wt.% of a white pigment, such as titanium dioxide, and 2-10 ppm of black pigment, such as carbon black. The synthetic fibers preferably further contain a fluorescent brighter in an amount of 0.01-0.05 wt.%. It is preferable that the average particle diameter of the white pigment is 0.2-1 &mu;m. <P>COPYRIGHT: (C)2009,JPO&amp;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.

  Synthetic fibers are produced by various methods, but the most common is a melt-spun thermoplastic resin (hereinafter referred to as a polymer). The polymer that is the raw material of the synthetic fiber is colorless and transparent by itself. Therefore, if the polymer 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 polymer.

  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 often used for clothing contain at most about 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 light-colored fabrics and white fabrics that are not dyed are easy to see through and have the disadvantage that they can be seen through when they are wetted with water, there is a demand for fabrics that do not show white or light-colored in the sports clothing field such as swimwear. .

  Conventionally, in order to improve such drawbacks, a method has been proposed in which a matting agent such as titanium oxide is mixed in a polymer in a larger amount than usual to make the synthetic fibers opaque. However, when a large amount of matting agent is added to the polymer, 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. In view of this, a composite fiber composed of a component containing a large amount of matting agent and a normal polymer 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.

JP-A-8-60485

  The present invention has been made in view of such a current situation, and an object of the present invention is to obtain a white / light-colored fiber excellent in anti-slipping property.

That is, the invention of the present application is an invention whose main purpose is a synthetic fiber comprising a thermoplastic resin containing 2 to 10% by weight of titanium oxide as a white pigment and 2 to 10 ppm of carbon black as a black pigment. In a preferred embodiment, the average particle size of the acid titanium to be 0.2 to 1 [mu] m, and the like to contain 0.01 to 0.05% by weight of fluorescent whitening agent in further.

  According to the present invention, white and light synthetic fibers excellent in spinning operability, post-process passability and shielding properties can be obtained. Such yarns are particularly suitable for sports clothing such as swimwear, and when used for outerwear, the color pattern of the clothing worn underneath is not visible, so it is highly fashionable. .

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, polyester can be preferably used.

The synthetic fiber of the present invention needs to contain a specific amount of white pigment. Specifically, it needs to be contained in an amount of 2 to 10% by weight, preferably 3 to 10% by weight, and particularly preferably 3 to 8% by weight.
If the amount of white pigment added is less than 2% by weight, the intended shielding effect cannot be obtained. When the added amount exceeds 10% by weight, troubles in spinning such as single yarn breakage and fluffing frequently occur, and the surface irregularities of the fibers are so severe that wear of spinning and post-processing machine parts becomes severe.

Considering the balance between prevention performance and spinning workability, after processing of sheer, the average particle size of the white pigment used is preferably from 0.2 to 1 [mu] m, 0. 2 to 0.8 μm is more preferable. 2 to 0.5 μm is particularly preferable.

  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.

  The synthetic fiber of the present invention needs to contain 2 ppm to 10 ppm of black pigment. Examples of the pigment include carbon black pigments, aniline black pigments, and iron oxide black pigments. Considering versatility and cost, the use of carbon black (CB) is most preferable.

  By including the black pigment, the fiber shielding effect is remarkably improved. When the amount of the black pigment is less than 2 ppm, the shielding effect is not improved. On the other hand, if it exceeds 10 ppm, the blackness (darkness) of the yarn becomes conspicuous, and it becomes unsuitable for applications that require bright yarn such as white and light colors. Considering the balance between the yarn shielding effect and the whiteness, the added amount of the black pigment is preferably 2 ppm to 6 ppm.

  The method for adding the black pigment is not particularly limited. Often used is a method in which a master chip to which a black pigment is added at a high concentration in advance and a normal chip are mixed and then spun. There is also a method in which chips and black pigment are mixed and used for spinning.

  In the present invention, it is preferable to add an optical brightener to the polymer. 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 referred to here means an original fluorescent whitening agent added to the polymer at the time of fiber production, and it is necessary to have something that does not hinder spinnability and stretchability. Can include stilbene fluorescent brighteners, imidazole fluorescent brighteners, imidazolone fluorescent brighteners, triazole fluorescent brighteners, thiazole fluorescent brighteners, and oxazole fluorescent brighteners.

  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.

  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, 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. Coloring by such a catalyst may be remarkably reduced by adding a small amount of dye / pigment.

  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. Further, a “slit yarn” obtained by cutting a film into a tape with a cutter may be used.

  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.

  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 expected to improve the shielding performance by changing.

  The 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 concealment 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 concealment performance can be exhibited. Of course, it is also possible to use for normal dyeing | staining.

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.
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 since the color of the garment itself can be emphasized, it has the effect of being excellent in design.

Hereinafter, the present invention will be specifically described by way of examples.
(Production example of fiber)
Using regular PET resin (containing 0.03% by weight of titanium oxide), a master chip (M1) having an average particle size of 0.3 μm and a titanium oxide content of 20% by weight was manufactured. M1 and the above-mentioned regular PET resin were mixed as appropriate. An appropriate amount of carbon black or fluorescent whitening agent (Clariant Japan Co., Ltd., HOSTALUX) was applied to the mixture to make a spinning raw material.
Using the above raw materials, spinning and drawing were performed by a conventional method to obtain a 56 dtex / 36 f fiber.

(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 uniformly wound around a white board (L value 91.0) and a blackboard (L value 20.2), and the L value was measured. When the L value of the sample wound on the white board is Lw, the L value of the sample wound on the blackboard is Lb, and the difference between them is ΔL, the smaller the ΔL, the better the shielding property.
As a result of actually examining with various samples, (1) If Lw is 91.5 or more, it has sufficient whiteness as a white fiber. (2) If ΔL is 3.5 or less, it was made into a fabric. Evaluation was made based on the indication that the shielding property at the time was sufficient.

  In addition, visual shielding performance was also evaluated. The alphabet printed at 28 points was pasted on the white plate, and the fibers were uniformly wound from above. The appearance of letters was evaluated on a 10-point scale. The score was so high that the numerical value was difficult to see. If the evaluation score is 8 or more, sufficient shielding properties are shown.

(Evaluation of abrasion)
A stainless steel wire having a wire diameter of 35 μm was set horizontally using a pulley. A 10-g weight was suspended at both ends of the stainless steel wire. The sample (fiber) was run at a constant speed so as to be vertical to the stainless steel wire and horizontal to the ground. The time from the start of running until the stainless steel wire was cut by friction with the sample was measured. The longer this time, the less wear of the parts of the actual spinning machine and post-processing equipment. From the correlation with the actual processing evaluation, if the cutting time is 60 seconds or more, it is practically sufficient.

Example 1
In producing the fiber according to the above production example, the amount of carbon black is 6 ppm in the fiber, and the amount of the optical brightener is 0.05% by weight (500 ppm) or 0 (not included). Fibers were produced with varying amounts as shown in Table 1.
All of the obtained fibers had sufficient strength and elongation as fibers.
The above evaluation was performed on the obtained fiber. The results are shown in Table 1.
In addition, the experiment No. Reference numeral 1 is a regular regular PET fiber (CB, not including a fluorescent brightening agent), which is a reference sample for evaluating abrasion.

As can be seen from Table 1, a sufficient shielding effect cannot be obtained if the titanium oxide is less than 2% by weight. Further, the wear evaluation tends to be inferior with the increase in titanium oxide, and it is expected that the operability will be hindered when the titanium oxide exceeds 10% by weight. Actually, test no. For Nos. 1 to 7, troubles such as yarn breakage, single yarn breakage, and fluffing during spinning were not observed, and an increase in the filtration pressure of the spinneret was not a problem. No. 8 had many problems in practical use due to a large increase in the filter pressure of the die, and a lot of single yarn breakage and fluffing.
On the other hand, most of the yarns shown in the table had sufficient whiteness as white fibers. The second thread was not white enough.

  Test No. in Table 1 Compare 4 and 5. In both cases, the addition amounts of titanium oxide and carbon black were the same. 4 does not contain an optical brightener. For this reason, the L value is No. Relatively low compared to 5. The value of Lb not shown in the table is also No. 4 is smaller. It can be seen that the addition of a fluorescent brightening agent is effective for enhancing whiteness.

Example 2
When producing the fiber according to the above production example, the amount of titanium oxide in the fiber is fixed at 6% by weight, the amount of the optical brightener is 0.05% by weight or 0 (no addition), and the amount of carbon black is adjusted. Various fibers were produced as shown in Table 2.
All of the obtained fibers had sufficient strength and elongation as fibers.
The above evaluation was performed on the obtained fiber. The results are shown in Table 2.
In addition, the experiment No. 11 is a regular regular PET fiber (same product as No. 1 in Example 1 above), which is a reference sample for evaluation of abrasion.

  As can be seen from Table 2, if the amount of carbon black is less than 2 ppm, the shielding properties are not sufficient. On the other hand, if it exceeds 10 ppm, the Lw value was low although the shielding property was sufficient. No. The actual appearance of 18 was too black to be called white fiber. These Nos. No troubles such as yarn breakage, single yarn breakage, and fluffing were observed in the fibers of 11 to 18, and an increase in the filtration pressure of the spinneret was not a problem.

  In addition, Test No. By comparing 15 and 16, the effect of the fluorescent brightener can be confirmed. That is, no. No. 16 is an equivalent composition No. 16. L value is higher than 15, and white appearance is excellent.

  The white and light synthetic fibers obtained by the present invention can be widely used in the clothing field including sports clothing such as swimwear.

Claims (4)

A synthetic fiber comprising a thermoplastic resin containing 2 to 10% by weight of titanium oxide as a white pigment and 2 to 10 ppm of carbon black as a black pigment. The synthetic fiber according to claim 1, wherein the titanium oxide has a particle size of 0.2 to 1 µm . The synthetic fiber according to claim 1 or 2, comprising 0.01 to 0.05% by weight of an optical brightener . The synthetic fiber according to any one of claims 1 to 3, wherein the thermoplastic resin is polyester .