JPH0473219A - Production of acrylic fiber having excellent whiteness - Google Patents

Abstract

PURPOSE:To obtain the subject fiber having excellent whiteness and extremely excellent feeling by wet-spinning a specific spinning dope, washing the fiber with water, applying a specific fluorescent dye and subjecting the fiber to drawing, drying and thermal relaxation treatment. CONSTITUTION:The spinning dope used in the present fiber is composed of (A) an acrylonitrile polymer having an acrylonitrile content of >=50 wt.% and 0.05-0.7 wt.% of an organic carboxylic acid and (B) 0.02-1.0 wt.% of a phosphite compound of formula I (R1 to R3 are 8-15C alkyl or phenyl group derivative) dissolved in one or more solvent selected from dimethylformamide, dimethylacetamide and dimethyl sulfoxide. The spinning dope is spun by wet- spinning, washed with water and drawn at a draw ratio of <= 5. The obtained gelatinous fiber is added with >=0.05 wt.% of (C) an aqueous solution of a benzimidazole derivative fluorescent dye of formula II and is subjected to drawing, drying and thermal relaxation treatment to obtain the objective fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 2] The present invention relates to a manufacturing method for obtaining acrylic fibers having extremely excellent whiteness and texture.

[Conventional technology]

One of the major drawbacks of acrylic fibers is that they have poor coloring stability against heat and are prone to yellowing during fiber manufacturing processes such as polymer dissolution, fiber drying, and fiber relaxation, making it difficult to obtain fibers with excellent whiteness. The disadvantage is that it is difficult.

In order to improve these drawbacks, methods have been developed to improve the whiteness by improving the composition and manufacturing conditions of acrylonitrile polymers, methods to minimize the trajectory history in the fiber manufacturing process, and methods to improve the spinning dope. Various methods of adding stabilizers have been tried, but they are still not satisfactory.

On the other hand, there are known methods to improve the whiteness of acrylic fibers, such as acidic hypochlorous acid sorter bleaching and post-treatment using fluorescent bleaching combined with a fluorescent brightener.These treatments can significantly improve the whiteness. However, it has the disadvantage that the texture of the obtained fibers is poor, and the working environment
There were problems with wastewater treatment. Other attempts have been made to improve the whiteness by mixing optical brighteners into the spinning dope, but this method has the disadvantage that the optical brighteners elute into the spinning bath during spinning and have an adverse effect on solvent recovery. .

Problems to be Solved by the Present Invention] An object of the present invention is to provide a method for producing acrylic fibers having excellent whiteness and texture.

3. Means for Solving the Problems 2. The present invention consists of a group of methylformamide, dimethylacetamide, and methylsulfate! 50★t% of acrylonitrile using one or more of the following as a solvent
Acrylonitrile polymer containing above, 005-07★t
% ('l' polymer) of n'organic carbonic acid (A) and 0.
01-], 0 wt% (based on polymer) of a phosphite compound (B) represented by the following formula (1) R,0-P-OR,-<1) OR3 (However, R1-3: ce-+5 Wet-spun a spinning dope consisting of an alkyl group or phenyl group derivative), washed it with water, and applied the following (2) to a gel-like fiber that had been stretched to 5 times or less.
An aqueous solution of the henzimitasol derivative fluorescent dye (C) shown by the formula was prepared so that the adhesion fi of the fluorescent dye (C) was 0.05 wt% (
The present invention provides a method for producing acrylic fibers with excellent whiteness, which is characterized in that the acrylic fibers are applied to dry fibers and then stretched, dried, and thermally relaxed.

To CH3 CH.

C@H.

The present invention will be explained in detail below.

In the present invention, the acrylonitrile-based polymer used contains 50 wt% or more of acrylonitrile, and the copolymerization component thereof is not particularly limited.
For example, unsaturated carboxylic acids and their salts such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid, acrylic acid esters such as methyl acrylate, ethyl acrylate, and butyl acrylate, and methacrylates such as methyl methacrylate and butyl methacrylate. Acid ester, methyl vinyl keto 7
vinyl esters such as vinyl formate and vinyl acetate, vinyl ethers such as methyl vinyl ether, acrylamide and its alkyl substituted products, unsaturated sulfonic acids such as vinyl sulfonic acid and methacryl sulfonic acid, and their salts;
Examples include styrene and its alkyl or halokene substituted products such as styrene/α-methylstyreno, allyl alcohol and its esters or ethers, vinyl chloride, vinyl halides such as vinylitine chloride, or vinylidenes.

In addition, as the organic carboxylic acid (A) here, phosphoric acid,
Examples include citric acid, malonic acid, succinic acid, and tartaric acid, among which citric acid is preferably used. The amount of organic carboxylic acid to be added should be set in consideration of the factors such as fiber transparency, heat-resistant coloring effect, and manufacturing cost, and is preferably set at 0.05 to 0.7 wt% based on the acrylonitrile polymer. If it is less than 0.05 wt%, the heat-resistant coloring is unsatisfactory, and if it exceeds 0.07 wt%, the whitening improvement rate will reach saturation, which is not only disadvantageous in terms of cost.
On the contrary, it is not preferable because it may promote coloring of the fibers.

The amount of the phosphite compound (B) represented by the formula (1) used in the present invention is 0% by weight based on the acrylonitrile polymer.

○ If it is less than 0.1 wt%, the heat-resistant coloring will be insufficient, and if it exceeds 10 wt%, the effect will be saturated, and the fiber itself will lose its luster, as well as falling off in the process after spinning. This may cause more problems in manufacturing.

Wet spinning in this invention may be performed by a known method.
It is preferable that the stretching ratio of the Kel-like fiber after water washing obtained by Type 9 spinning is 5 times or less; if it exceeds 5 times, it will be difficult for fluorescent dyes to enter the Kel-like fiber in the subsequent process, and therefore the dyeing fastness of the obtained fiber will be reduced. I don't like it too much.

The fluorescent dye represented by the formula (2) used in the present invention (
C) is attached to the Kel-like fibers in an amount of 0.05 wt% or more based on the dry fibers, or ○ 05 to 0.5
WL% is preferable, and if it exceeds 0.5vt%, the whiteness improvement rate becomes saturated, which is disadvantageous in terms of cost. After the fluorescent dye has been exhausted, the Kel-like fibers are stretched and dried in the usual manner, and then thermally relaxed.

The acrylic fibers obtained in this manner always have a superior feel and whiteness compared to fibers obtained by conventional post-treatment methods.

3 fruits 1ii8! U trap Hereinafter, the present invention will be explained in more detail with reference to Examples.

In this example, the whiteness of the fibers was measured using spectroscopic light vtt.
<Makhesu 2020 Plus, Makhess Co., Ltd.! Using a Ds5 light source and a 10-degree field of view, colorimetry was performed using a Ds5 light source, and the Lb value was determined using the following formula from the Lb value and the b value.

Lb=V+(100-L)/51'-b
'Therefore, the smaller the Lb value, the better the whiteness.

Example 1 Comparative Examples 1 to 4 Acrylonitrile polymers containing 93.1 wt% acrylonitrile and 6.9 wt% methyl acrylate were mixed at a concentration of 23 wt%.
7 is dissolved in methyl acetamide to give a total weight of 70% by weight, and as shown in Table 1, each wt% of 7-euric acid and allyl alkyl phosphite (relative to tO form) are added thereto and dissolved at 70°C to obtain a spinning stock solution. And so.

Next, this spinning stock solution was prepared with a hole diameter of 0.06 mmφ and a number of holes of 500.
It was spun into a coagulation bath of a 53 wt% dimethylacetamide aqueous solution at a temperature of 35 °C using a 0 H spinneret, and the obtained filament was stretched twice in purified water to dry the fluorescent dye of formula (2). After dressing 0.3% based on the fiber weight, 25
It was stretched twice, dried, and thermally relaxed at 130'C to obtain a fiber with white fluorescence.

Their whiteness is shown in Table 1.

Table 4 [), 1 0.01. 0.
31 29*l, *2 wt% (relative to polymer) *3 wt% (relative to dry fiber) Example 2 Acrylonitrile 94.2 wt%, hinyl acetate 531%
0.5 wL% of acrylonitrile-based polymer was dissolved in methylacetamide to a concentration of 26 wt%, and 0.3 wt% of citric acid was added to it.
(based on the polymer) and 2 wt % of allyl alkyl (based on the polymer) were added and dissolved at 65°C to obtain a spinning stock solution.

This spinning stock solution was prepared with a hole diameter of 0.05 mmφ and a hole number of 5000F (
400C 7 methyl acetamic acid 50W using a nozzle.
Wet spinning was carried out in a coagulation bath consisting of a t% aqueous solution, the obtained filament was washed in submerged water, stretched 3 times, and the fluorescent dye of the formula (2) was added with ○ 35wt%, and it was stretched twice. Stretched, coated with Safanol AW-1000 (Sanyo Kasei Co., Ltd. oil refining agent) at 03★t% (based on dry fiber) and dried, +2
A fiber with white fluorescence was obtained by thermal relaxation at 0°C.

Table 2 shows the whiteness and texture of this fiber.

Comparative Example 5 A fiber was obtained in the same manner as in Example 2 except that no fluorescent dye was added, and after refining, the formula (2) (% formula %) g/ρ, So/Um, xametaphosphate ○ 25 g/
Evening, acidic sodium hyposulfite O, 125g/(+7)p
After exposing the H4,2 aqueous solution to fluorescence for 30 minutes at a bath ratio of 1.50.95°C, 0.3 wt% of the oil agent (Saphanol AW-1000) used in Example 2 was applied and dried to produce a white color. A fluorescent fiber was obtained.

Table 2 shows the whiteness and suitability of the fibers thus obtained.

Table 2 Lb value Texture Example 2' 2.3, Good comparative example 5
, 22 Bad Example 3 Acrylonitrile 59★t% and Vinyritine Chloride 40w
t%, an acrylonitrile polymer having a composition of 1★t% of sodium methallylsulfonate was dissolved in /methylformamide, and further 0.4 wt% of 7-euric acid (based on the polymer), tris(monononylphenyl)phosphiho, 2wt% (
(copolymer) was added to obtain a spinning stock solution. This spinning stock solution was spun into three
Wet spinning was carried out in a coagulation bath consisting of a 55 wt% aqueous solution of methylformamide at 5°C, and the obtained filament was washed with hot water at 80°C, stretched 20 times, and the fluorescent dye of formula (2) was added. 0.4 wt% (based on dry fiber) was attached, further stretched 30 times, dried, and thermally relaxed at 110°C to obtain a fiber with white fluorescence.

The Lb value of this fiber was 41. On the other hand, 7
The Lb value of the fiber obtained in the same manner except that uric acid and tris(monononylphenyl)phosphite were not added was 58.

From these results, it was confirmed that according to the manufacturing method of the present invention, acrylic fibers with excellent whiteness and good texture could be obtained.

[Effect of the Invention 1 As explained above, according to the production method of the present invention, acrylic fibers with extremely excellent whiteness and texture can be obtained.

Applicant: Mitsubishi Rayon Co., Ltd.

Claims (1)

[Scope of Claims] An acrylonitrile polymer containing 50 wt% or more of acrylonitrile, 0.05 to 0.7 wt% ( organic carboxylic acid (A) and 0.02 to 1.0
Phosphite compound (B) shown by the following formula (1) in wt% (based on polymer) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼...
・(1) Wet-spun a spinning dope consisting of OR, (R_1_-_3: alkyl group or phenyl group derivative of C_8_-_1_5), washed with water, and applied the following to gel-like fibers stretched to 5 times or less. An aqueous solution of the benzimidazole derivative fluorescent dye (C) shown by the formula (2) is prepared so that the adhesion amount of the fluorescent dye (C) is 0.
A method for producing acrylic fibers with excellent whiteness, which comprises applying acrylic fibers in an amount of 0.5 wt% or more (based on dry fibers), then stretching, drying, and thermally relaxing. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(2)