JPH0782605A - Splittable acrylic yarn - Google Patents

Abstract

PURPOSE:To obtain splittable acrylic yarn suitable for clothing and materials, having excellent handleability of process and economic efficiency. CONSTITUTION:This splittable acrylic yarn comprises a mixture of 30-90wt.% of a acrylonitrile-based polymer and 10-70wt.% of an acrylic resin-based polymer having >=30 deg.C and <=100 deg.C glass transition temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved splittable acrylic fiber which can be used for clothing and materials.

[0002]

2. Description of the Related Art Acrylic fibers are mainly used for clothing, interior applications and material applications by taking advantage of their excellent coloring properties, vividness and fastness, dyeing characteristics and excellent fiber physical properties such as light resistance and corrosion resistance. Widely used. Usually, acrylic fibers are produced by wet spinning, dry wet spinning, and dry spinning. In all of these spinning methods, a spinning stock solution in which an acrylic polymer is dissolved in a solvent is discharged from a spinneret and shaped into a yarn. After that, complicated steps such as desolvation, washing, stretching, drying and heat treatment are required.

In recent years, the development of techniques for reducing the fineness of acrylic fibers has been vigorously carried out. It was studied to limit the ordinary acrylic fiber manufacturing technology, which miniaturizes single fibers by miniaturizing the diameter of the spinneret and increasing the draw ratio.
It is possible to make it extremely fine, and it has been industrialized as a manufacturing technology for artificial suede. Further, when a low-concentration spinning stock solution of an acrylonitrile-based polymer having a special composition is used (Japanese Patent Laid-Open No. 5-33212), it is possible to make single fibers to a fineness of about 0.02d. In general, when the single fiber diameter is small, fuzzing is likely to occur, and the process passability is deteriorated due to winding around a roller, a guide, or the like, a yarn breakage, or the like during the manufacturing process. Therefore, even if a monofilament having a fineness less than this is obtained, it is difficult to obtain good processability.

Under the circumstances, studies have been conducted on ultrafine fiber application of the composite spinning technique, that is, sea-island type composite spinning and peeling type composite spinning. The composite spinning has an advantage that a relatively thick fiber having a single fiber fineness of several d can be handled during the spinning process, and an ultrafine fiber can be obtained by post-treatment. Sea-island composite spinning uses a special composite spinneret
By forming a sea-island fiber with a two-phase structure, the sea component is dissolved and removed by a solvent and the island component is left. In the peelable composite spinning, the fiber once spun with an additive polymer that imparts splitting properties is heat treated, This is a method of splitting after post-treatment such as chemical treatment. With melt-spun fibers such as nylon and polyester, it is possible to obtain ultrafine fibers by such a method, and since the process is simpler than that of acrylic fibers, it has been industrially applied.

Also for acrylic fibers, ultrafine fiber application has been investigated by applying sea-island type composite spinning similar to melt spinning. For example, an acrylonitrile polymer as an island component and a solvent-soluble polymer as a sea component 2
A technology for obtaining ultrafine fibers by removing the sea component with a solvent after obtaining the fibers having a phase structure (Japanese Patent Laid-Open No. 3-69609).
No. 3-69666), and it has been clarified that the obtained fiber exhibits excellent performance as an air filter. However, these methods have not been put to practical use because they require an expensive spinneret, the acrylic fiber manufacturing process is more complicated than the melt-spun fiber manufacturing process, and the process passability is low.

On the other hand, in the release type composite spinning, various additive polymers such as methyl methacrylate (Japanese Patent Publication No. 47-47535) and polyalkylene glycol (Japanese Patent Application Laid-Open Nos. 2-200857 and 2) for the purpose of imparting splitting property. -2349
79, No. 4-126857), vinyl chloride, and chlorinated vinyl chloride (Japanese Patent Publication No. 4-78727).

However, in the method in which methyl methacrylate is used as the additive polymer, fine powder may be generated in the production process of the raw yarn, or fine powder may be generated from the final product. Further, in the method of using polyalkylene glycol as the additive polymer, since polyalkylene glycol is soluble in water, it may fall off in the coagulation bath and may also fall off from the final product, which is a problem in process passability and product quality. Is recognized. Further, the method of using vinyl chloride or chlorinated vinyl chloride as an additive polymer seems to be effective for modacrylic fiber, but does not give sufficient effect for acrylic fiber which is the object of the present invention. Therefore, the conventional technology is excellent in process passability and economical efficiency, and 0.0
It is hard to say that this is sufficient as a technique for producing an acrylic fiber having a fineness of 1d or less.

[0008]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a splittable acrylic fiber without sacrificing process passability and economical efficiency.

[0009]

Means and Actions for Solving the Problems The present inventors have
As a result of intensive studies to achieve the above object, the present invention has been achieved. That is, the gist of the present invention is to provide an acrylic resin-based polymer 10 having an acrylonitrile-based polymer of 30 to 90% by weight and a glass transition temperature of 30 ° C. or higher and 100 ° C. or lower.
˜70% by weight in a split acrylic fiber consisting of a mixture.

The present invention will be described in more detail below.
The present inventors maintain good spinnability, suppress fluffing, do not cause fibers to fall out in the coagulation bath, and can easily split fibers by mechanical force, such as good process passability. In order to obtain a superfine fiber having a fineness of 0.01 d or less, it has been earnestly studied about an additive for imparting splitting property to acrylic fiber, and it is important that the additive polymer has the following properties. I came to think that. That is, the spinning dope containing the added polymer must have a uniform phase. Microphase separation occurs during filament formation in the coagulation bath. The domain size of the described microphase separation is on the order of micron to submicron. The acrylonitrile polymer and the additive polymer have an appropriate difference in viscoelasticity.

The present inventors have searched for additive polymers in light of the above conditions and examined the amount of addition, and as a result, have found that acrylic resin polymers are extremely effective.

In the present invention, it is necessary that the acrylic resin polymer used as the additive polymer has a glass transition temperature Tg of 30 ° C. or higher and 100 ° C. or lower.
When the glass transition temperature is lower than 30 ° C, splitting property is rapidly lowered and the raw yarn is fused, and when it exceeds 100 ° C, fine powder is generated during the process and differentiation is generated from the final product. The processability is reduced and the quality of the final product is also reduced.

In the present invention, it is necessary to add 10 to 30% by weight of the acrylic resin polymer used as the additive polymer. When the addition amount is less than 10% by weight, sufficient splitting property cannot be obtained, and when the addition amount exceeds 70% by weight, the process passability is lowered due to fusion of the raw yarn in the spinning process, and It is not suitable for the purpose of the invention.

In the present invention, it is desirable that the spinning solution of the acrylic fiber to which the acrylic resin polymer is added has a uniform phase. When the spinning dope has a heterogeneous phase, defects such as yarn breakage, dropping of the additive polymer, and fluffing of the raw yarn tend to occur.

The acrylic resin polymer used in the present invention is preferably insoluble in water. If it is soluble in water, it may fall into the coagulation bath and cause fluffing of the raw yarn and yarn breakage, resulting in poor processability.

The monomers constituting the acrylic resin-based polymer used in the present invention are not particularly limited, but examples thereof include the following monomers. That is, it is represented by acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, and the like. Acrylic esters, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl acrylate, lauryl acrylate, methacrylic Methacrylic acid esters represented by 2-hydroxyethyl acid, hydroxypropyl methacrylate, diethylaminoethylethyl methacrylate and the like can be mentioned. Also,
Copolymerize unsaturated monomers such as maleic acid, itaconic acid, acrylamide, N-methylol acrylamide, diacetone acrylamide, styrene, vinyltoluene, vinyl acetate, vinyl chloride, vinylidene chloride, vinylidene bromide, vinyl fluoride, vinylidene fluoride. You can also do it.

The molecular weight of the acrylic resin polymer used in the present invention is not particularly limited, but the molecular weight is 10,000 or more and 10 or more.
It is desirable that it is less than or equal to 0,000. If the molecular weight is less than 10,000, it causes the fibers to fall off in the coagulation bath. If the molecular weight exceeds 1,000,000, the splitting property will decrease.

A low molecular weight compound may be optionally added to the acrylic resin polymer used in the present invention. Further, in some cases, fine particles such as inorganic substances and metals may be added.

The acrylonitrile-based polymer used in the present invention is not particularly limited as long as it is a polymer that constitutes ordinary acrylic fibers, but it is preferable that the acrylonitrile-based polymer contains 50% by weight or more of acrylonitrile as a monomer component. If the acrylonitrile content in the polymer is less than 50% by weight, the raw yarn loses its original properties as an acrylic fiber,
It is not suitable for the purpose of the present invention.

As the copolymerization component of acrylonitrile,
There is no particular limitation as long as it is a copolymerization monomer that constitutes a normal acrylic fiber, and examples thereof include the following monomers. That is, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate,
Acrylic esters represented by 2-ethylhexyl acrylate, 2-hydroxyl ethyl acrylate, hydroxypropyl acrylate, etc., methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate. , T-butyl methacrylate, n-hexyl methacrylate, cyclohexyl acrylate, lauryl acrylate,
Methacrylic acid esters represented by 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, diethylaminoethyl ethyl methacrylate, acrylic acid, methacrylic acid, maleic acid, itaconic acid, acrylamide, N-methylol acrylamide, diacetone acrylamide, It is an unsaturated monomer such as styrene, vinyltoluene, vinyl acetate, vinyl chloride, vinylidene chloride, vinylidene bromide, vinyl fluoride and vinylidene fluoride. Further, for the purpose of improving dyeing, p-sulfophenyl methallyl ether, methallyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, 2-acrylamide-
You may copolymerize 2-methyl propane sulfonic acid, these alkali metal salts, etc.

The molecular weight of the acrylonitrile polymer used in the present invention is not particularly limited, but a molecular weight of 100,000 or more and 1,000,000 or less is desirable. If the molecular weight is less than 100,000, the spinnability tends to decrease, and at the same time, the yarn quality of the raw yarn tends to deteriorate. If the molecular weight exceeds 1,000,000, the polymer concentration that gives the optimum viscosity of the spinning dope will be low, and the productivity will tend to be low.

As the solvent of the spinning dope used in the present invention,
There is no particular limitation as long as it is a common solvent that dissolves each polymer of an acrylonitrile-based polymer and an acrylic resin-based polymer, and examples of such a solvent include dimethylformamide, dimethylacetamide, dimethylsulfoxide, and the like.

The method for preparing the spinning dope of the acrylic resin-based polymer and the acrylonitrile-based polymer of the present invention is not particularly limited. For example, each polymer is added to a solvent to prepare a slurry and then dissolved.
A method of batch mixing undiluted solutions of each polymer separately,
Examples include a method of in-line mixing a stock solution in which each polymer is separately dissolved using a static mixer or the like.

When the spinning solution obtained as described above is spun by the wet spinning method, it is discharged from an ordinary spinneret into a coagulating bath and coagulated to form a yarn called coagulated yarn. As the coagulation bath, a mixed solution of a stock solution for spinning and water is generally used. The coagulated yarn is continuously desolvated, washed,
A raw yarn is obtained through processes such as drawing, drying and heat treatment.

In some cases, the raw yarn is cut into a desired length and subjected to a splitting treatment to become an ultrafine fiber. The splitting treatment is a step of dividing the raw yarn into a single fiber by applying a mechanical force, and for example, various mixers or water jets can be used.

[0026]

EXAMPLES The present invention will be described in more detail below with reference to examples.

(Examples 1 to 6, Comparative Examples 1 to 4) 1. Polymerization of acrylonitrile polymer As acrylonitrile (AN), vinyl acetate (VAc), methyl acrylate (MA), sodium methallyl sulfonate (MS), vinylidene chloride (VdC)
1) and acrylonitrile-based polymers A1 and A in Table 1 by an aqueous suspension polymerization method using ammonium persulfate and sodium acid sulfite as a redox-based polymerization initiator.
2, A3 was obtained. The weight average molecular weight (Mw) is dimethylformamide as a solvent, and the intrinsic viscosity [η] at 25 ° C.
Is a value calculated by the following formula.

[Η] = 3.35 × 10 ^-4 Mw
^0.72

[0029]

[Table 1]

2. Polymerization of acrylic resin-based polymer The acrylic resin-based polymer shown in Table 2 was obtained by the following method. -Polymerization of acrylic resin-based polymer (B1) 100 parts by weight of methyl methacrylate (MMA), azobisisobutyronitrile (AIBN) as a polymerization initiator, and n-octyl mercaptan as a chain transfer agent, respectively.
1 part by weight of a mixture of methyl methacrylate / 2-sulfoethyl methacrylate sodium salt copolymer 0.01
1 part by weight and 0.35 part by weight of sodium sulfate were mixed in 150 parts by weight of pure water, charged in a pressure resistant polymerization kettle equipped with a jacket, a stirrer and a thermometer and polymerized at 80 ° C. After the internal temperature reached the peak, the temperature was maintained at 120 ° C. for 30 minutes, cooled, filtered, washed with water, and dried to obtain an acrylic resin polymer B1.

Polymerization of acrylic resin-based polymer (B2) 90 parts by weight of methyl methacrylate (MMA) and 10 parts by weight of methyl acrylate (MA) in place of 100 parts by weight of methyl methacrylate (MMA), n-octyl mercaptan 0 Acrylic resin polymer B2 was obtained in the same manner as acrylic resin polymer B1 except that the amount was changed to 0.23 parts by weight instead of 1 part by weight.

Polymerization of acrylic resin-based polymer (B3) 20 parts by weight of methyl methacrylate (MMA) and 80 parts by weight of n-butyl methacrylate (n-BMA) in place of 100 parts by weight of methyl methacrylate (MMA), n -Acrylic resin-based polymer B3 was obtained in the same manner as acrylic resin-based polymer B1 except that 0.18 parts by weight was used instead of 0.1 part by weight of octyl mercaptan.

Polymerization of acrylic resin polymer (B4) 100 parts by weight of methyl methacrylate (MMA) was replaced with 100 parts by weight of n-butyl methacrylate (n-BMA), n
-0.20 in place of 0.1 part by weight of octyl mercaptan
Acrylic resin-based polymer B4 was obtained in the same manner as acrylic resin-based polymer B1 except that the weight part was used.

The molecular weight of the acrylic resin polymer (M
w) was measured under normal conditions by gel permeation chromatography using tetrahydrofuran as a solvent. The glass transition temperature was measured by freeze-grinding a sample and using a differential thermal analyzer.

[0035]

[Table 2]

3. Spinning Acrylonitrile-based polymer and acrylic resin-based polymer were mixed in the mixing ratio shown in Table 3, and dimethylacetamide (DM
It was dissolved in Ac) so that the polymer concentration was 24% by weight to prepare a spinning dope. The number of holes is 50 and the diameter is 0.0
Using a 6 mmφ spinneret, 40 ° C, 30 wt% DM
It was discharged into a coagulation bath of an Ac aqueous solution and wet-spun at 1.2 times the draft of spinning. The coagulated yarn was subjected to washing and drawing steps, treated with an oil agent, and dried with a heating roller to obtain a raw yarn having a fineness of 2d.

4. Split fiber process Cut the raw yarn to a length of about 5 mm and use 100 g of water for 1 g of raw yarn.
ml, household mixer (Mitsubishi Electric Home Co., Ltd. J
(M-G32 type), and pulverization processing was performed for 15 minutes in the lowest rotation speed mode.

5. Evaluation of splitting property Splitting property was evaluated by the following method which is a simplified version of JIS-P8121 method. After drying the crushed raw yarn, 0.5 g was weighed, 500 ml of water was added, and the mixture was sufficiently stirred and dispersed. This was poured into a conical stainless steel mesh (400 mesh) and adhered almost uniformly on the mesh to form a cake layer. This mesh is placed on a funnel, 60 ml of water is poured instantly, the time until 50 ml of water is dripped, the filtration time t
(Sec) was measured. The volume of water was measured using a graduated cylinder, and the filtration time was measured using a stopwatch. This measurement was performed 10 times for each sample, and the average value was calculated.
The filtration time is 2.2 to 2.2 for samples that have not been split.
It was 2.3 seconds.

6. Measurement of fineness of split fiber The sample adhered to the stainless mesh in the item of evaluation of split fiber was dried and then scanned with a scanning electron microscope (J-20 T-20).
The degree of splitting to 0.01 d or less was observed using a mold.

From the filtration time and the observation with a scanning electron microscope, the splitting property was classified as shown in Table 3. It is considered that the filtration time reflects the denseness of the cake layer formed of the fiber sample formed on the stainless mesh, that is, the fineness of the split fibers and the split ratio.

[0041]

[Table 3]

Table 4 shows the evaluation results of the splitting property and process passability of each sample.

[0043]

[Table 4]

[0044]

Industrial Applicability The present invention is a splittable fiber which gives a sufficient ratio of ultrafine fibers having a fineness of 0.01 d or less,
It has excellent processability and economic efficiency, and is extremely useful as an acrylic fiber for clothing and industrial materials.

Claims (1)

[Claims] 1. A split acrylic fiber composed of a mixture of 30 to 90% by weight of an acrylonitrile polymer and 10 to 70% by weight of an acrylic resin polymer having a glass transition temperature of 30 ° C. or higher and 100 ° C. or lower.