JPH08325833A - Ultrafine acrylic fiber and its production - Google Patents

Abstract

PURPOSE: To obtain an ultrafine acrylic fiber having excellent deep color dyeing performance and low-temperature dyeability and hygroscopicity without necessitating annealing relaxation treatment by copolymerizing a p-styrenesulfonic acid (salt) at a specific copolymerization ratio. CONSTITUTION: This ultrafine fiber having a fineness of 0.01-0.5de is produced from an acrylonitrile copolymer having a specific viscosity of 0.05-0.5 and copolymerized with p-styrenesulfonic acid and/or its salt at a copolymerization ratio of 0.4-1.4mol%. The fiber dispenses with an annealing relaxation treatment to promote the impregnation of a dye into the fiber and has high color fastness.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an acrylic ultrafine fiber and a method for producing the same. More specifically, dark color dyeability,
The present invention relates to an acrylic ultrafine fiber excellent in dyeability and hygroscopicity at low temperature and a method for producing the same.

[0002]

2. Description of the Related Art Acrylic fibers have been widely used for clothing, bedding, interiors, etc. by taking advantage of their vivid coloring and soft texture. However, as the fibers are made thinner to enhance the soft texture, the apparent dye concentration decreases. Therefore, in an acrylic ultrafine fiber made of a conventional copolymerized acrylonitrile copolymer, the orientation relaxation of the acrylic copolymer in the fiber is relaxed by an annealing relaxation step, and the apparent dye is increased by increasing the penetration of the cationic dye into the fiber. The density is increased and the dyeability is expressed. However, with ultrafine fibers, the frequency of adhesion between fibers in the annealing relaxation step is extremely higher than that with thick denier fibers, and the process stability is deteriorated.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to increase the amount of dye adsorbed and increase the apparent dye concentration without increasing the permeation of the dye into the fiber by annealing relaxation. Properties) and dyeing fastness are improved, dyeing at low temperature is possible, and hygroscopicity is excellent, and an acrylic ultrafine fiber and a method for producing the same are provided.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved and have reached the present invention.

That is, the first gist of the present invention is to use p-styrenesulfonic acid and / or its salt in an amount of 0.4-1.
Fineness of 0.01 to 4 composed of 4 mol% copolymerized acrylonitrile-based copolymer having a specific viscosity of 0.05 to 0.5
The second gist is in 0.5 denier acrylic ultrafine fibers, and the second gist is 0.4-1.4 mol% of p-styrenesulfonic acid and / or its salt, which has a specific viscosity of 0.05-
A spinning stock solution consisting of an acrylonitrile-based copolymer of 0.5 and a solvent is discharged from the spinneret, and after coagulation, the yarn is washed and stretched, and secondarily stretched to give a total stretching ratio of 4 times or more. And a method for producing an acrylic ultrafine fiber.

The present invention will be described in detail below. The acrylic ultrafine fiber of the present invention is made of an acrylonitrile copolymer obtained by copolymerizing p-styrenesulfonic acid and / or a salt thereof in an amount of 0.4 to 1.4 mol%. It is necessary for improving dyeability and hygroscopicity.

When the copolymerization ratio of p-styrenesulfonic acid and / or its salt exceeds 1.4 mol%, the dyeing speed and the dye adsorption amount are saturated even if the dye is added in an excessive amount, so that the performance is improved. Not only that, but in the polymerization step, the particles of the produced polymer are remarkable, the washing efficiency and the dehydration filterability are rapidly deteriorated, and a large amount of the polymerization catalyst residue remains, which in turn causes the frequency of yarn breakage in the spinning step. It is not preferable because it increases. Further, if the copolymerization rate of p-styrenesulfonic acid and / or its salt is less than 0.4 mol%, the amount of dye adsorbed is small and the apparent dye concentration cannot be increased unless annealing is relaxed. It will be out of the way.

The specific viscosity of the above-mentioned acrylonitrile copolymer is required to be 0.05 to 0.5 which can ensure the spinnability and more preferably 0.1 to 0.25. If the specific viscosity is less than 0.05, the spinnability is lowered and it becomes difficult to take it off in a coagulation bath. Further, when it exceeds 0.5, in order to keep the viscosity of the spinning dope in the optimum spinning range,
It is necessary to keep the undiluted solution solid content low, the swelling degree of the spun tow, that is, the water content increases, and the spun tow is not only whitened but also the drying energy load becomes large, which is not preferable.

In the present invention, the specific viscosity η _sp is calculated from the viscosity η of the acrylonitrile copolymer solution prepared by dissolving 0.1 g of the acrylonitrile copolymer in 100 ml of dimethylformamide and the viscosity η _{0 of the} solvent by the following formula. did. All viscosity measurements were performed at 25 ° C. with an Ubbelohde viscometer. η _sp = (η-η ₀ ) / η ₀

The acrylonitrile-based copolymer constituting the acrylic ultrafine fibers of the present invention is a vinyl-based copolymer which is copolymerized with acrylonitrile as a main component and the above-mentioned p-styrenesulfonic acid and / or its salt, as well as these monomers. The monomer may be copolymerized at 5.0 mol% or less.

The copolymerizable vinyl monomer includes (meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and hexyl (meth) acrylate. Esters, vinyl chloride, vinyl bromide,
Vinyl halides such as vinylidene chloride, acids such as (meth) acrylic acid, itaconic acid, crotonic acid and salts thereof, maleic imide, phenylmaleimide, (meth) acrylamide, styrene, α-methylstyrene,
Methyl acrylate and vinyl acetate are preferable, and methyl acrylate is more preferable, since they include vinyl acetate and the like, because they improve the spinnability of the ultrafine acrylic fiber.

The acrylic ultrafine fiber of the present invention has the above-mentioned constitution and can improve the deep color dyeing property, the dyeing property at low temperature and the hygroscopic property even when the fineness is in the range of 0.01 to 0.2 denier. is there.

Next, a method for producing the acrylic ultrafine fiber of the present invention will be described. The acrylonitrile-based copolymer of the present invention can be polymerized by any known method such as aqueous suspension polymerization, emulsion polymerization, and solution polymerization, but the unreacted monomer is small and the unreacted monomer is solidified during spinning. Aqueous suspension polymerization and emulsion polymerization that do not contaminate the bath are preferable, and an aqueous suspension polymerization method that enables continuous production and has high production efficiency is more preferable.

The acrylonitrile copolymer is dissolved in a solvent that dissolves it through known washing, dehydration and drying steps to prepare a spinning dope. As a solvent for dissolving the acrylonitrile-based copolymer, a solvent such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, an aqueous nitric acid solution, an aqueous rhodan salt solution, an aqueous zinc chloride solution can be used.

Spinning of the acrylic ultrafine fiber of the present invention can be carried out by any of wet, dry and semi-dry wet spinning methods, but the wet spinning method is preferred. The spinning stock solution discharged from the spinneret and coagulated is further subjected to secondary stretching after washing and stretching, and the total stretching ratio is 4 times or more.
It is important for obtaining ultrafine fibers of 1 to 0.2 denier.

[0016]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the examples, acrylonitrile is AN, methyl acrylate is MA, vinyl acetate is AV,
p-Styrene sulfonic acid sodium was described as NaSS, respectively.

It should be noted that measurement of polymerization rate, dehydration / filterability, specific viscosity,
The intrinsic viscosity, spinnability, shrinkage rate, dye adsorption rate (dark color dyeability evaluation), dyeing fastness, hygroscopicity and fineness were evaluated by the following methods.

(Measurement of Polymerization Rate) The polymer aqueous solution dispersion sampled from the reactor overflow outlet was filtered to separate the polymer content, and the polymer yield was defined as the polymerization rate.

(Dehydration filterability) The filter adhesion of the polymerized slurry in an Oliver type continuous filter was visually evaluated.

(Specific viscosity) The specific viscosity η _sp is calculated by the following formula from the viscosity η of the acrylonitrile copolymer solution prepared by dissolving 0.1 g of the acrylonitrile copolymer in 100 ml of dimethylformamide and the viscosity η _{0 of the} solvent. did. All viscosity measurements were performed at 25 ° C. with an Ubbelohde viscometer.

Η _sp = (η-η ₀ ) / η ₀

(Spinnability) Spinnability was evaluated by visually observing the following points. Coagulation bath Thread breakage in orifice spinneret, stretchability in coagulation bath Washing Stretching Stretchability in wash bath, detergency Secondary stretching Secondary stretchability with preheating roller Good process passability × Thread breakage and washing in spinneret Poorness, winding around rolls, poor stretchability, generation of adhesive fibers, etc.

(Shrinkage) The shrinkage of the spun tow was measured by annealing relaxation at 130 ° C.

(Dye adsorption rate-dark color dyeability evaluation) 40% ow
Cationic Blue with excess amount of f
K-GLH (Hodogaya Chemical), bath ratio 1/50, pH =
Prepare a dyeing solution under the conditions of 4.5, and defatted sample raw cotton is heated to 100 ° C for 30 minutes, and 90 minutes for 1 minute.
Heated at 00 ° C. The dyed cotton is washed in running water for 20 minutes, dried and then dissolved in dimethylformamide.
The dye adsorption amount was determined from a calibration curve prepared in advance from the absorbance at 00 nm.

(Dyeing fastness) 10% owf cationic dye Cathion Blue K-GLH (Hodogaya Chemical Co., Ltd.) (bath ratio 1/50, pH = 4.5, 100 for 30 minutes)
The raw cotton dyed by heating to 100 ° C. and heating at 100 ° C. for 90 minutes) was exposed to carbon arc light for 48 hours (J
IS-L-0842 method). The dyeing fastness is based on the dyeing fastness test method and is based on the discolored gray scale (JIS-
Grades 5 to 1 were evaluated according to L-0804).

(Hygroscopicity) The hygroscopicity test was carried out by drying fibers at 105 ° C. to a constant weight at 24 ° C. and 55% RH.
The sample was left in an atmosphere of (relative humidity) for 24 hours, the weight was measured in the atmosphere, and the weight increase was calculated as% by weight.

(Fineness) The fineness was measured according to JIS-1015.

(Example 1) (Polymerization of Acrylonitrile Copolymer) In a polymerization kettle (using a stirring blade), deionized exchanged water and a monomer mixture of a predetermined ratio were added: water / monomer = 4.5 / 1 (weight ratio). Was charged with 1.5 parts by weight of a redox polymerization initiator, ammonium persulfate, and sodium bisulfite, 6.0, based on 100 parts by weight of the monomer.
Parts, ferrous sulfate _{(FeSO 4 · 7H 2 O)} 0.000
5 parts by weight and 0.7 parts by weight of sulfuric acid were dissolved in deionized exchange water and continuously supplied. Adjust the pH of the reaction solution to 3 with sulfuric acid supply, maintain the temperature of the polymerization reaction solution at 60 ° C, perform sufficient stirring, and set the residence time for each experiment so that the molecular weight is such that the specified specific viscosity is obtained. Instead, the polymer aqueous dispersion (polymerization slurry) was continuously taken out from the polymerization reactor reaction overflow port. 0.5 parts by weight of ammonium oxalate and 1.5 parts by weight of ammonium bicarbonate were added to the polymerization slurry.
An aqueous solution of a polymerization terminator dissolved in 0 part by weight of deionized exchange water was added so that the pH of the polymerization slurry became 5.5 to 6.0, and the unreacted monomer and the polymerization aid residue were weighed with an Oliver type continuous filtration device. Separated from coalescence. The obtained wet polymer was molded into pellets and then dried with an air dryer to obtain an acrylonitrile copolymer.

(Spinning) An acrylonitrile copolymer was dissolved in dimethylacetamide (hereinafter referred to as DMAC) to a concentration of 20% by weight to prepare a spinning stock solution. The spinning solution is 50
After the temperature was adjusted to 0 ° C., the mixture was filtered through a sintered metal filter with a filtration accuracy of 10 μm in two stages, and discharged from a spinning die having a pore size of 50 μm and the number of holes of 70,000 into a coagulation bath of a 55 ° C. 30% aqueous DMAC solution. The draft of the spinning stock solution withdrawal rate / discharge linear velocity in the coagulation bath was adjusted in the range of 2 to 6 times. Furthermore, the washing draw ratio in boiling water was adjusted in the range of 1.8 to 2.5 times so that the residual DMAC concentration in the spun tow was 0.05% or less. Apply oil to the spun tow after washing and
After drying with a drying roller of No. 1, a secondary heating treatment of 1.25 to 2.5 times was performed with a preheating roller at 180 ° C. to give crimp.

The ultrafine acrylic fibers obtained are shown in Tables 1 and 2,
It had the characteristic values shown in Table 3.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

Example 2 Various polymers polymerized by the same method as in Example 1 were spun, and the dyeing speeds at 80 ° C. and 100 ° C. of spun tow raw cotton without annealing relaxation were compared. As a measuring method, a dyeing solution was prepared so that the cationic dye Cation Blue K-GLH (manufactured by Hodogaya Chemical Co., Ltd.) of 10% owf, a bath ratio of 1/50, and a pH of 4.5 were prepared, and a sample cotton was used for 120 minutes for 80 minutes Heated at ° C. 10 minutes, 20 minutes, 40 minutes, 60 after starting dyeing
The dye solution for 120 minutes was sampled, the absorbance at 600 nm was measured, the dye concentration in the dye solution was determined from the calibration curve prepared in advance, and the dyeing rate was calculated from the dye concentration decreased by dyeing the raw cotton. The obtained ultrafine acrylic fiber had the characteristic values shown in Table 4.

[0035]

[Table 4]

[0036]

According to the present invention described above, an ultrafine acrylic resin having sufficient dark color dyeing property even if the annealing relaxation step is omitted and having improved dyeing property at low temperature, dyeing fastness and hygroscopicity. Fibers are obtained. Further, since the deep color dyeing property of the ultrafine fibers can be exhibited without passing through the annealing relaxation step, the thermal relaxation step in the spinning step can be omitted or simplified. Therefore, it is possible to increase the apparent dye concentration of the ultrafine fiber while avoiding the adhesion of the fiber, which has been a cause of trouble in the spinning relaxation process of the acrylic ultrafine fiber.

Claims (2)

[Claims] 1. A fineness 0 composed of an acrylonitrile copolymer having a specific viscosity of 0.05 to 0.5 obtained by copolymerizing p-styrenesulfonic acid and / or its salt in an amount of 0.4 to 1.4 mol%. 0.01-0.5 denier acrylic ultrafine fibers. 2. From an acrylonitrile copolymer having a specific viscosity of 0.05 to 0.5 obtained by copolymerizing p-styrenesulfonic acid and / or a salt thereof in an amount of 0.4 to 1.4 mol%, and a solvent. A spinning stock solution is discharged from a spinneret, and after coagulation, the yarn is washed and stretched, and secondarily stretched to obtain a total stretching ratio of 4 times or more.