JPH036264B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an acrylic long fiber bundle having a novel texture. Acrylic long fibers are widely used for their soft texture, excellent photo-selectivity, and excellent dyeing and color development.
The smooth, rough and hard feel of natural fibers such as linen and cotton,
It lacks a lightweight feel and tends to be unsuitable for spring and summer products. Known methods for imparting a smooth and lightweight feel without impairing the properties of acrylic long fibers include welding or adhering the fiber interface with a solvent or heat treatment, or flattening the cross section of the fiber bundle. There is. For example, special public relations
No. 12616, Special Publication No. 18384, No. 18384, Japanese Patent Publication No. 101032, No. 1983
Although the method described in Japanese Patent Publication No. 49-42880 is widely known, there are practical problems such as welding and bonding due to external forces such as twisting and rubbing caused by guides, travelers, etc. in the post-processing process. It is inevitable that the fibers will continue to split and split, and their effectiveness will decrease.
Furthermore, when fiber bundles are flattened, stress is concentrated in specific parts, causing problems such as splitting, fluffing, and hangnails, forcing countermeasures such as reducing processing speed. Losses are inevitable. Post-processing processes for acrylic long fibers include yarn winding, twisting, plying, false twisting, soft cheese wrapping,
The process to obtain the product is long, including cheese dyeing, skein dyeing, cone winding, knitting, etc., and bonded flat yarns require special handling, which causes an increase in costs. In particular, processes that use a ring winder and processes such as false twisting are subject to strong external forces such as twisting and rubbing, and the reality is that we have no choice but to develop products that avoid these processes. The present inventors conducted extensive studies to solve these problems and completed the present invention. In the present invention, a fiber bundle composed of filaments with a dry strength of 2.5 g/d or less is treated with an aqueous solution of a solvent for the fiber, and the aqueous solution is contained in an amount of 1.5 to 3.0 times as much.
It is characterized by rapidly removing moisture through short-time high-temperature treatment at 165℃ for 0.2 to 0.6 seconds, and further strengthening the bonding of welded or bonded parts by short-time high-temperature treatment at 220 to 250℃ for 0.3 to 0.8 seconds. , an acrylic fiber bundle of 30 to 600 deniers consisting of a plurality of filaments, and the ratio of the longitudinal direction to the latitudinal direction of the cross section of the fiber bundle is 1:
It is in the range of 1.0 to 9.0, and the constituent filaments are partially and locally strongly welded or bonded, and the ratio is
This is a method for producing acrylic long fiber bundles with a content of 30 to 90%. According to the method of the present invention, it is possible to wind the material using a high-speed ring winder and pass through the false twisting process, which has the advantage of expanding the range of products available, and can also be used to improve the productivity of the processing process. be. In the acrylic long fiber bundle of the present invention, 30 to 90% of adjacent filaments constituting its cross section are firmly welded or bonded, and preferably 10 to 40% of voids are present within the cross section. The fiber bundle has appropriate flexibility and maintains excellent post-processability. In other words, by leaving 10 to 70% of the non-welded or non-bonded part, the fiber bundle is given appropriate flexibility, and the void part has the function of relieving strong external force when it is applied. These play the role of preventing the adhesion or welding portion from splitting or splitting. Furthermore, the parts that are strongly welded or glued locally and locally give the fibers rigidity and give them a smooth feel, while the internal voids help give them a soft and lightweight feel. . The size of the fiber bundle of the present invention ranges from 30 to 600 d,
It is necessary for the fiber bundle cross section to limit the ratio (cross section ratio) of the maximum length in the warp direction to the maximum length in the weft direction to a range of 1:1.0 to 9.0. Items exceeding the range of 600d or those with a cross-sectional ratio exceeding 9.0 have poor resistance to external force in the post-processing process, causing fuzzing and thread breakage, and worsening the passage of the post-processing process. In order to prevent this, countermeasures such as reducing productivity are required. The raw material polymer used in the present invention may be either an acrylonitrile homopolymer or a copolymer with other vinyl monomers, and solvents for dissolving it include dimethylformamide, dimethylacetamide, dimethyl sulfoxide, an aqueous solution of rhodan salt, and nitric acid. An aqueous solution or the like is used. The spinning method may be dry, wet, semi-dry, etc.
After forming the yarn, it goes through the process of desolvation and becomes 80~
Stretch 2 to 4 times in a 100°C hot water bath or normal pressure steam. In this process, the orientation of the fiber axis direction is kept slight, and the fiber structure is such that welding or adhesion at the fiber interface can easily proceed in a short time, that is, the fiber dry strength is 2.5.
g/d or less, preferably in the range of 1.8 to 2.5 g/d. Next, the water-swollen fiber bundle is treated with a water-soluble or water-dispersible fiber oil, and the oil is applied uniformly so that the constituent filaments do not adhere to each other in the next drying process. The purpose of this oil attachment is to prevent the filament from adhering and to prevent the fiber bundle from being damaged by the guides, and the type, amount, and method of attachment of the oil may be freely selected depending on the purpose. Next, the acrylic fiber bundle is immersed in an aqueous solution of a solvent that has a dissolving effect, and the aqueous solution is attached and/or contained in an amount 1.5 to 3.0 times that of the fiber bundle, and heated at 135 to 165°C.
Moisture is removed by instantaneous evaporation on a drying roller for 0.2 to 0.6 seconds. Each filament that makes up the fiber bundle, which has been completely separated by the oil treatment in the previous process, vibrates violently in the boiling state during this water removal process, causing air bubbles to get inside the fibers. At the same time, partially
It is presumed that the local welding or adhesion progresses in a uniformly distributed manner without being unevenly distributed in the cross section of the fiber bundle. To actively accelerate this state, it is necessary to rapidly evaporate the excess water solution, increase the freedom of the constituent filaments and minimize fiber orientation. An ordinary guide or Niprol is used to adjust the amount of aqueous solution retained in the fiber bundle. Solvents used in the present invention include one type of aqueous solution or a mixed aqueous solution of two or more of propylene carbonate, ethylene carbonate, dimethylsulfone, tetramethylsulfone, dimethylformamide, dimethylacetamide, γ-butyrolactone, dimethylsulfoxide, trimethylene carbonate, etc. is used. The amount of solvent applied here varies depending on the strength of the dissolving power depending on the type of solvent, the desired rate of welding or adhesion, the number of constituent filaments, etc.
150d/60f using ethylene carbonate as solvent
In the case of a fiber bundle, an aqueous solution concentration of 2.2% and twice the amount of aqueous solution attached to the fiber bundle can sufficiently achieve the purpose. Next, the fiber bundle from which moisture has been removed is further processed for 220 to 250
℃, short time high temperature treatment for 0.3-0.8 seconds. This treatment can strengthen the bonding of the welded or bonded portions while maintaining the voids in the fiber bundle. This high temperature treatment is preferably carried out in the following order. i.e. 135-165℃℃ drying roller for 0.8-2.5 seconds,
165-220℃, 1.0-3.0 on the same drying roller
220-250℃, followed by 2-step treatment.
Contact with high temperature for 0.3-0.8 seconds. This step has the purpose of making the welding or adhesion stronger and relaxing the fiber by releasing the strain inside the fiber, and also to remove the remaining solvent by thermal decomposition or volatilization. In this step, it is necessary to perform high temperature treatment for a short time in order to color the fibers and prevent deterioration. Examples of high-temperature processing equipment used in the present invention include infrared heaters, high-temperature hot air dryers, etc.
In order to instantaneously transfer heat to the fiber bundle, a contact heating plate type device with a built-in heater is preferred. Example Acrylonitrile 92.7% by weight, vinyl acetate 7
Dimethylacetamide was added to a copolymer with an intrinsic viscosity of 1.60 (25° C.) consisting of 0.3% by weight of sodium methallylsulfonate and 0.3% by weight of sodium methallylsulfonate to prepare a spinning stock solution with a solid content concentration of 23.5%. While discharging the spinning stock solution at a speed of 0.213 ml/min/hole from a 60-hole nozzle with a hole diameter of 0.12 mm installed at a distance of 8 mm from the coagulation bath liquid level, a bath containing 70% dimethylacetamide and a temperature of 40°C was The coagulated thread was coagulated inside the machine and wound at a speed of 48.4 m/min. Next, the solvent was removed in a hot water bath at 70°C, and then stretched 3.5 times in boiling water to 180°C.
The speed was set at m/min. At this time, the dry strength is 2.1g/
d. The elongation was 13%. Next, after treatment with a common water-soluble oil agent, it is dried on a drying roller with a surface temperature of 140℃ for 3 minutes.
It was dried for seconds to completely remove moisture. continuation
After immersing it in a 2.2% ethylene carbonate aqueous solution for 0.05 seconds and squeezing it with Nipprol to adjust the amount of adhering aqueous solution to 2.5 times that of the fiber, all moisture was instantly removed in 0.4 seconds using a drying roller with a surface temperature of 140°C. Then dry roller surface temperature 140℃, 1.6 seconds and 180℃
After heat treatment in two stages for 2 seconds at 235℃
A third heat treatment was performed by contacting them for 0.6 seconds on a hot plate at ℃. Subsequently, an ordinary straight oil agent of 2% by weight based on the fiber was applied again, and the fiber was wound on a high-speed ring winder at a speed of 180 m/min. At this time, the yarn tension was 37 g and the spindle rotation speed was 4000 rpm. The wound raw yarn was in good condition with no fluff or yarn breakage. In addition, it has excellent post-processability, and the resulting knitted fabric has a strong crisp feel.
It had a very lightweight feel. As shown in the drawing, the cross section of the obtained yarn shows that 86.7% of the yarn is welded or bonded.
The porosity was 25% and the cross-sectional ratio was 2.6 times. Comparative Examples 1 to 3 The conditions of the example were partially changed, and the treatments shown in Table 1 were performed to obtain yarn specimens.

[Table] In Comparative Example 1, the winding condition in the high-speed ring winder was good, and no fuzz or thread breakage was observed. When the specimen was evaluated after passing through the third stage of heat treatment, the welding or adhesion rate was 87%, the cross section was 2.6 times higher, and the porosity was 19.4%. After soft winding (approximately 1 kg), cheese dyeing, and cone winding, this raw yarn was knitted into a 24G Amagasa weave, and the texture was evaluated and found to be less stiff. When we removed a part of this knitted fabric and evaluated it,
Welding, adhesion rate is 28%, cross section ratio is 2.2 times, porosity is 8%
However, the welding and adhesion rates were significantly reduced, and a satisfactory texture could not be obtained. In Comparative Example 2, there were many fluffs and thread breaks during winding with a high-speed ring winder, and winding was impossible. Although the yarn tension was changed to 40 to 50 g and the spindle rotation speed was changed to 3000 to 4000 rpm, it was not possible to suppress fuzzing and yarn breakage. When the specimen in the third stage of heat treatment was evaluated, the cross-sectional ratio was 10 times larger;
The welding rate was 92%, the porosity was 16%, and the large cross-sectional ratio was an obstacle to winding. In Comparative Example 3, the raw yarn had strong rigidity, and fluff frequently occurred in the traveler portion of the high-speed ring winder, so that satisfactory results could not be obtained. This yarn had a cross-sectional ratio of 3.2 times, a welding and adhesion rate of 97%, and a porosity of 13%, and had a high welding and adhesion rate and strong rigidity.

[Brief explanation of drawings]

The drawing is an enlarged cross-sectional view of a fiber bundle obtained in an example.

Claims (1)

[Claims] 1. A fiber bundle composed of filaments with a dry strength of 2.5 g/d or less is treated with an aqueous solvent solution of the fiber,
Contain 1.5 to 3.0 times the aqueous solution, 135 to 165℃, 0.2
Multiple filaments that are characterized by rapidly removing moisture with a short-time high temperature treatment of ~0.6 seconds, and further strengthening the bonding of welded or bonded parts by a short-time high temperature treatment of 220-250℃ for 0.3-0.8 seconds. consists of
An acrylic fiber bundle of 30 to 600 deniers, the ratio of the longitudinal direction to the latitudinal direction of the cross section of the fiber bundle is in the range of 1:1.0 to 9.0, and the constituent filaments are strongly welded or bonded locally. , a method for producing acrylic long fiber bundles whose ratio is 30 to 90%.