JPH04153315A - Polyamide fiber resistant to yellowing and its production - Google Patents

Abstract

PURPOSE:To obtain the subject fiber having excellent whiteness and light- resistance and useful for packaging material, etc., by adding and reacting a specific compound in the melt-spinning of a polyamide fiber to reduce the terminal amino group content below a prescribed level and adding a prescribed fluorescent brightener. CONSTITUTION:The objective fiber is produced by adding and reacting triazoloxy-S-triazine in the production of a polyamide fiber by melt-spinning to reduce the terminal amino group content to <=10g-equivalent/10<6>g and, at the same time, adding 0.005-0.2wt.% of a benzoxazole-type fluorescent brightener.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polyamide fiber that exhibits significantly high white discoloration and does not yellow, and a method for producing the same.

(Prior Art) Polyamide fibers have excellent chemical and mechanical properties,
It is widely used as a fiber for clothing and industrial materials.

However, 9 ordinary polyamide fibers have a problem in that their whitening is insufficient, especially for applications where whitening is required. In order to solve this problem, it has been proposed to add an optical brightener when producing polyamide fibers1.
For example, JP-A-6420321 discloses a white spun-dyed polyamide fiber containing a benzoxazole fluorescent whitening agent, a white inorganic compound, and a dispersion medium.

On the other hand, polyamide fibers have the advantage that they can be easily dyed with acid dyes because they have amino terminal groups, but on the other hand, they have the problem of being susceptible to yellowing due to light or gas, or yellowing due to wrapping paper materials.

Conventionally, as a method for preventing yellowing of polyamide fibers, particularly yellowing caused by wrapping paper materials, there has been no effective method of modifying polyamide fibers, and various methods of modifying wrapping paper materials have been proposed. For example, a method has been proposed in which a solution of a specific compound is coated or impregnated onto the inner liner of a wrapping paper material or a cardboard packaging container (Japanese Patent Publication No. 56-48640, Japanese Patent Publication No. 60-7759, etc.).

Also, as a way to prevent yellowing caused by gas.

A method for reducing the amount of amino terminal groups in fibers has been proposed.1 For example, in JP-A-1-229810, an acid or an acid anhydride is added and reacted during melt spinning of polyamide to reduce the amount of terminal amino groups to 10 to 30 g. A method for obtaining equivalent weight/106g is disclosed. However, with this method, it was not possible to prevent yellowing due to the wrapping paper material.

Yellowing is a particular problem in products that require whitening as described above, and polyamide fibers that exhibit high whitening and do not yellow have not yet been developed.

(Problem to be solved by the invention) The present invention exhibits significantly high white discoloration and excellent light resistance.

The present invention also aims to provide polyamide fibers that do not cause yellowing due to packaging materials, etc., and a method for producing the same.

(Means for Solving the Problems) In order to solve the above problems, the present inventors, as a result of intensive studies, have extremely reduced the amount of amino terminal groups in polyamide and added a benzoxazole fluorescent brightener to the fibers. It is effective to include it.

To reduce the amount of amino end groups in polyamide.

It was discovered that a method of adding triaryloxy-8-triazine during melt spinning and causing a reaction 9 is effective 1
We have arrived at the present invention.

That is, 1. The gist of the present invention is as follows.
An anti-yellowing polyamide fiber containing 5 to 0.2% by weight.

(2) When producing polyamide fibers by the melt spinning method, triaryloxy-8-triazine is added and reacted to reduce the amount of amino terminal groups to 10 g equivalent/106 g or less, and the benzoxazole fluorescent brightener is added to 0. .0
A method for producing an anti-yellowing polyamide fiber, characterized by adding and containing 05 to 0.2% by weight.

Below, nine aspects of the present invention will be explained in detail.

As the triaryloxy-S triazine in the method of the present invention, those described in Japanese Patent Publication No. 46-5068 can be used, and specific examples include triphenyl-8-cyanurate, tris(p-methyl- Phenyl 1-3-cyanurate.

Examples include tris(p-t-butyl-phenyl 1-3-cyanurate).

The appropriate amount of triaryloxy-8-triazine to be added is 0.7 to 2.5 times the mole, preferably 0.9 to 2.3 times the mole of the amino terminal group of the polyamide, and the amount added is within this range. Therefore, the amount of amino terminal groups of the polyamide can be made to be 10 g equivalent/10 6 g or less without impairing spinning properties. Unless the amount of amino terminal groups is 10 g equivalent/io6 g or less, yellowing of the polyamide fiber cannot be prevented.

Furthermore, as the benzoxazole fluorescent brightener, East Bright 0B-1 (trade name) commercially available from Eastman Kodak Company is preferably used.

The amount of the optical brightener added must be 0.005 to 0.2% by weight, preferably 0.01 to 0.1% by weight. If the amount added is too small, the effect of improving whitening of fibers will be insufficient.

If you use too much, not only will the skin whitening effect be saturated, but
The fibers tend to yellow, which is undesirable.

The polyamide used in the method of the present invention is not particularly limited as long as it can be melt-spun, but typical examples include nylon 6, nylon 66, and nylon 46.

Note that the polyamide fiber of the present invention may contain about 0.2 to 3.0% by weight of a white inorganic compound such as titanium dioxide as a matting agent.

(Example) Next, the present invention will be explained by giving examples.

Examples and Comparative Examples Relative viscosity (96% sulfuric acid as solvent, concentration 1 g/dll!
.

(measured at a temperature of 25°C) is 2.70. Terminal amino group amount is 62
g equivalent/106 g of nylon 6 chips with triphenyl-8-cyanurate and optical brightener: yeast bly)
OB-1 was added in the amount shown in Table 1 and mixed.

The fibers were spun at a spinning temperature of 270°C and a residence time up to the spinneret for 15 minutes, wound at a speed of 800 m/min, and stretched at a stretching speed of 500 m/min and a draw ratio of 4 times.
A 70d/24f nylon 6 fiber was obtained.

A tubular knitted fabric was made using the obtained nylon 6 fibers, and the white skin, light resistance, and yellowing were evaluated using the following methods.

white degree Determined by sensory test.

Light resistance was determined by measuring with a carbon arc fade meter according to JIS L 0842.

Yellowing Resistance ■Nitrogen oxide gas fastness was determined according to JIS L 0842.

(2) The sample was cut to a size of 6 cm x 6 cm, wrapped in aluminum foil with a commercially available cardboard cut to the same size, and left at 80° C. for 100 hours, and then evaluated by a sensory test.

Here are the evaluation results for the tube knitted fabric above.

Characteristics of drawn yarn They are shown in Table 1 along with their sex values.

No. table Note: Nα1゜ 2゜ 6 is a comparative example, Nα3 to 5 are Example L ◎: Extremely good ○: Yun Ryuko.

△: Slightly poor.

×: Defective.

(Effects of the Invention) According to the present invention, polyamide fibers are provided which have extremely high whiteness, excellent light resistance, and do not yellow due to packaging materials or the like.

Furthermore, according to the method of the present invention, such polyamide fibers can be easily produced by simply adding additives during melt spinning.

Patent applicant: Unitika Co., Ltd.

Claims (2)

[Claims] (1) An anti-yellowing polyamide comprising a polyamide having an amino terminal group weight of 10 g equivalent/10^6 g or less, and containing 0.005 to 0.2% by weight of a benzoxazole optical brightener. fiber. (2) When producing polyamide fibers by the melt spinning method, triaryloxy-S-triazine is added and reacted to reduce the amount of amino terminal groups to 10 g equivalent/10^6 g or less, and a benzoxazole fluorescent brightener 0.
A method for producing an anti-yellowing polyamide fiber, characterized by adding and containing 0.005 to 0.2% by weight.