JPH0233321A - Polyester fiber - Google Patents

Abstract

PURPOSE:To obtain a sheath-core type polyester fiber with safety from skin- attacking excellent in whiteness and suitable for sanitary goods, etc., and composed of a core part consisting of a polyester containing an optical whitening agent and a sheath part consisting of another polyester without an optical whitening agent. CONSTITUTION:A polyester 1 (preferably polyethylene terephthalate with >=50mol% ethylene terephthalate repeating unit and 1.5-1.8 relative viscosity) containing an optical whitening agent (e.g., bis-benzoxazole derivative), preferably in an amount of 0.01-0.5wt.% and another polyester 2 without a whitening agent are separately fed to a conjugate spinning nozzle unit and subjected to melt spinning, thus obtaining a sheath-core type polyester fiber composed of a core part consisting of a polyester containing an optical whitening agent and a sheath part consisting of another polyester without a whitening agent and having the core part, preferably in the ratio accounting for 20-80% of the fiber cross section.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to polyester fibers with excellent white discoloration.

[Conventional technology]

Conventionally, polyester fibers used for sanitary materials require high white discoloration, making it difficult to use optical brighteners due to the risk of skin problems such as staining, sores, and rashes. The white discoloration was improved by increasing the amount of titanium oxide added, adding a small amount of cobalt compound to give it a blue tint, or using germanium oxide as a polymerization catalyst, but no sufficient effect could be obtained. There wasn't.

[Inventive power 1: Problem to be solved] The present invention surprisingly shows that even when a fluorescent brightener is contained in the core of a composite fiber having a core-sheath type structure, an effect of improving whitening can be obtained. The object of the present invention is to provide a polyester fiber which sufficiently improves whitening by adding an optical brightener to a polyester polymer and is also safe to the skin.

[Means to solve the problem]

The present invention resides in a polyester fiber characterized in that the polyester fiber is a composite polyester fiber with a core-sheath structure, and the core portion is made of a polymer containing a fluorescent whitening agent.

Figures 1 (a), (b), and (c) K show cross-sectional views of examples of polyester fibers of the present invention, in which 1 shows the polymer containing fluorescent and brightening agent in the core, and 2 shows the sheath part. 1 indicates a combination containing no optical brightener, and 3 indicates a hollow portion.

Note that the core of the polyester fiber of the present invention is marked in Figure 1, (
As shown in (b) and (c), instead of a single core, two or more cores may be used. Also, Fig. 2 is the same as Fig. 1 of the present invention (
FIG. 2 is a longitudinal cross-sectional view of an example of a composite spinneret device used for producing composite polyester fibers having a core-sheath type structure in (b). Here, 4 in FIG. 2 (a) is a distribution plate, 5 is a front plate, and 6
indicates the nozzle plate. Figure 2 (b) shows the x − of the front plate discharge hole.
x' cross-sectional view, Figure 2 (c) is Y-Y of the nozzle plate discharge hole
'This is a cross-sectional view.

The composite polyester fiber of the present invention is manufactured by melting the optical brightener-containing polyester 1 aggregate constituting the core and the polyester polymer constituting the sheath using an extruder, and then supplying the composite spinneret to a composite spinneret device for melt-spinning. It is done by doing. After that, follow the usual methods, air cooling, applying oil,
The fibers are taken up with rollers, stretched, heat treated, or further crimped to form fibers.

The polymer used in the polyester fiber of the present invention is polyethylene tere-7crate, in which 50 mol% or more is composed of repeating units of ethylene terephthalate. The degree of polymerization is a relative viscosity (metacresol, 25°C) of 1.5 to 1.
A range of 8 is preferred.

Other diols such as butanediol and hexanediol, inctaric acid,
Other dicarboxylic acids of the 5-sodium sulfoiphthalic acid group may also be combined.

The polyester fiber of the present invention has a core-sheath type structure, and the ratio of the core portion to the cross section of the fiber is preferably 20 to 80%. If the core content is less than 20%, the effect of containing the optical brightener will be small, and if it exceeds 80%, one core part will be exposed on a part of the fiber surface.

In the present invention, the optical brightener contained in the core polymer is 270
There is no particular restriction as long as it does not decompose in the temperature range of ~290°C and can be melted and dispersed in the polyester polymer. Examples of such optical brighteners include bis-benzoxazole derivatives, triazole phenylcoumarin derivatives, and bissteryl biphenyl derivatives.

There are no particular restrictions on the method of incorporating the optical brightener into the core polymer, but a master batch containing a high concentration of the optical brightener may be prepared in advance and mixed uniformly with the 1-unit mixture and melt-kneaded. Alternatively, a powder of a fluorescent whitening agent may be uniformly adhered to the surface of the polymer and then melt-kneaded. Furthermore, the optical brightener may be melted or dissolved, turned into a liquid, and then injected into the molten polymer to mix the molten Fll.

The content of optical brightener in the core polymer is 0.01 to 0.
The content is preferably 5% by weight; if it is less than 0.01% by weight, no effect of improving white skin can be obtained, and if it exceeds 0.5% by weight, no significant effect can be expected.

〔Effect of the invention〕

The polyester fiber of the present invention has a high white discoloration despite containing a fluorescent whitening agent in the core, and is safe to the skin, so it is suitable for sanitary materials and underwear materials.

〔Example〕

The present invention will be explained below with reference to Examples.

Example A polyethylene terephthalate polymer (relative viscosity 1.63, 250
°C) masterbatch and polyethylene terephthalate 1 containing 0.50% by weight of titanium oxide (relative viscosity 1.5
8) are uniformly blended in a weight ratio of 1:19, and a chip containing O, O5 xii% of a fluorescent whitening agent and a sheath component containing 0.50% by weight of titanium oxide based on the combined core part and tr.
Polyethylene terephthalate 1 combination (relative viscosity 1.63
) chips were fed to different extruders and heated at 290°C.
After melting with a gear pump, the core/sheath ratio is 1/1 and the mixture is introduced into the composite spinneret device shown in FIG. 2 (270).
The composite was spun at ℃.

The discharge hole of the front plate was 0.5 mm in diameter, and the gap between the front plate and the nozzle plate was 0.2 m. The discharge hole of the nozzle plate has the shape shown in Fig. 2 (c) (W = 0.3 m, l = 0.15 m, R =
1.8 sin) was used.

The spun yarn was air-cooled and oiled according to a conventional method, and then taken off and bundled at 680 rx/min.

After this, the undrawn yarn was conditioned for 4 hours at 25°C and 65RH%, and then a drawing machine was used to
Stretched 4.0 times in 1 minute, then passed through a push-crimping device to give crimps, and then heat-treated at 150°C for 15 minutes.
Cut to m+. The quality of the fiber obtained in this way was
Shown in the table.

The obtained fibers had a high level of white discoloration despite the fact that no optical brightener was present on the fiber surface, no leaching of the optical brightener was observed during the manufacturing process, and there was very little yarn breakage.

In addition, the white discoloration of the fibers is measured using a colorimeter 0PTICAL manufactured by Nippon Kishokusha.
5 using ENSOR model Z-11.

Y and I were calculated by measuring the Y and Z values and using the following formula.

It was expressed as a value (the smaller the value, the higher the white discoloration).

Comparative Example Table 1 also shows the yarn quality of fibers obtained under the same conditions as in Examples, except that the core polymer was not blended with the optical brightener masterbatch.

Table 1

[Brief explanation of the drawing]

Figures 1 (a), (b), and (c) are cross-sectional views of examples of the fibers of the present invention, and Figures 2 (a), (b), and C→ are spinneret apparatuses for producing the fibers of the present invention. FIG. 2 is a longitudinal cross-sectional view and a partial cross-sectional view of an example of FIG. 1...Core polymer 2...Sheath polymer 3...Hollow part (Inotaka 71 Figure C) Figure 2 (A)

Claims (1)

[Claims] A polyester fiber characterized in that the polyester fiber is a composite polyester fiber having a core-sheath type structure, and the core portion is made of a polymer containing a fluorescent whitening agent.