JP5014799B2 - Hollow acrylic synthetic fiber - Google Patents

Description

  The present invention relates to a hollow acrylic synthetic fiber that is suitable mainly for pile applications, is lightweight, soft, has good hairiness, and has a matting effect.

Acrylic synthetic fibers are widely used in fields such as bores, seals, fleeces, and high piles because of their soft feel and ease of processing. Among pile applications, especially those used for apparel are desired to be lightweight, and various proposals have been made to reduce the weight of fibers. For example, a hollow acrylic fiber (Patent Document 1) in which two spinning dope solutions are spun into a core and sheath and have a hollow portion between the core and sheath, and an acrylic synthetic fiber having a substantially C-shaped cross section spun using a C-shaped nozzle Patent Document 2 proposes an acrylic synthetic fiber (Patent Documents 3 and 4) that forms a hollow portion by forming a skin layer and a core layer and then performing heat treatment. However, these are particularly thick because they require a complicated process of using two spinning dope solutions and using a core-sheath nozzle (Patent Document 1) and only a cross-section that is close to a circle (Patent Documents 2, 3, and 4). There are problems such as a feeling of fineness in touch and a poor hair separation.
JP-A-9-78355 JP2003-96618 JP 61-28014 A Republished patent WO00 / 70133

  An object of the present invention is to obtain an acrylic synthetic fiber that is lightweight, soft, has good hair brushing properties and has a matting effect at a large fineness.

  That is, the present invention is a hollow acrylic synthetic fiber characterized in that the major axis / minor axis of the fiber cross section is a cross section of 3 or more and has a hollow portion, and the light transmittance of a single fiber at 580 nm to 600 nm is 70%. The following are preferred.

  Also preferred are those obtained by spinning an acrylonitrile-based polymer spinning solution using a spinneret having holes in which at least one shape selected from a circle, an ellipse and a rhombus is connected.

  The hollow acrylic synthetic fiber of the present invention is light and soft and excellent in hair handling, and has pores inside the fiber, so that it has a matte and so-called dull feeling expression effect. For this reason, it is particularly suitable for pile fibers having a large fineness, and a lightweight, soft and high-quality pile fabric can be obtained.

It is an example of the hole shape of the spinneret used for this invention. It is a model figure of the skin core structure of the fiber cross section from the coagulation bath in this invention. It is a fiber cross-section photograph after passing through the hollowing process in the present invention.

Explanation of symbols

1: Skin layer 2: Core layer

The acrylonitrile copolymer in the present invention is obtained by copolymerizing 30 to 92% by weight of acrylonitrile and 8 to 70% by weight of one or more vinyl group-containing monomers copolymerizable with acrylonitrile as main components. Is used.
Examples of vinyl group-containing monomers that can be copolymerized with acrylonitrile include vinyl esters such as acrylic acid, methacrylic acid, vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, vinyl acetate, or vinyl pyrrolidone, vinyl pyridine, and the like. Alkyl substituted product, acrylic acid ester, methacrylic acid ester, acrylic acid amide, methacrylic acid amide or mono- and dialkyl substituted products thereof, allyl sulfonic acid, methallyl sulfonic acid, p-styrene sulfonic acid, 2-acrylamido-2-methyl Examples include propanesulfonic acid, isoprenesulfonic acid, and alkali metal salts thereof.

  The acrylonitrile-based copolymer is dissolved in an organic solvent such as acetone, acetonitrile, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, or an inorganic solvent such as zinc chloride, nitric acid, rhodan salt, etc. Inorganic or organic pigments or stabilizers effective for rust prevention, coloring prevention, light resistance, etc., or additives for adjusting inorganic or organic gloss and whiteness may be used.

    Next, it spins to a coagulation bath through the spinneret which has the hole which connected 3 or more of at least 1 sort (s) selected from a circle | round | yen, an ellipse, or a rhombus as shown in FIG. By using these nozzles, the skin core structure formed in the coagulation bath has a structure having a relatively large core part inside each circle, ellipse or rhombus, as shown in FIG. Here, in order to form the skin layer, the concentration of the organic solvent or the inorganic solvent in the bath or both is preferably 1 to 50% by weight, more preferably 5 to 35% by weight, and the temperature is preferably − It is 10 ° C to + 50 ° C, more preferably 0 ° C to + 30 ° C. Thereafter, it passes through a low temperature bath of 10 to 55 ° C, and further passes through a hot water bath of 55 to 95 ° C, preferably 60 to 80 ° C. In these baths, 1.1 to 10 times, preferably 2 to 8 times Is stretched. Thereafter, in order to further reduce the solvent content in the wet yarn, it may be passed through saturated steam at 90 to 100 ° C.

  When the solvent content is reduced, the hollowing rate tends to increase in the subsequent hollowing step. The wet yarn from the washing bath or from the saturated steam process usually has a liquid content of about 60 to 200% by weight, and is dried at a low temperature of 5 to 70 ° C., preferably 20 to 50 ° C. 5 to 40% by weight, preferably 15 to 30% by weight. At this time, it is considered that a large amount of water and solvent are present in the core part. The yarn having the adjusted liquid content is passed through a hollowing step, and this step causes water and solvent present in the core portion to instantaneously expand and volatilize to generate voids in the core portion. Accordingly, the hollowing step is not limited as long as the yarn can be rapidly heated, and examples thereof include general dry heat treatment with hot air, wet heat treatment, or a constant temperature bath using an organic compound such as polyethylene glycol and glycerin. . The dry heat and wet heat treatment are preferably performed at 120 to 180 ° C., and the constant temperature bath is preferably performed at 100 to 140 ° C. Thereby, the fiber which the space | gap produced in the core part like FIG. 3 is obtained. After the hollowing step, if necessary, stretching and heat treatment are performed to obtain a fiber having a hollow portion having a generally flat cross-sectional shape.

  Examples Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Prior to describing the examples, measurement methods and the like will be described.

(Measurement method of fiber hollowing ratio)
The cross-sectional shape of the sample fiber bundle was photographed with a scanning electron microscope at a magnification at which about 100 fiber cross-sections were inserted, and the 100 fiber cross-sections having a porosity of 5% or more were hollowed out. And calculated by the following formula.
Hollowing rate (%) = [(number of fibers with a porosity of 5% or more) / (number of fibers measured)] × 100
The porosity was calculated by the following formula from the area (A) of the hollow portion that is in the form of holes or meshes in the fiber cross section and the area (B) other than the hollow portion.
Porosity (%) = [A area / (A + B area)]
In addition, about the cross section which the hollow part bursts and the space | gap part is opening toward the fiber surface, since it is unpreferable from the point of fiber strength or a feeling, the existence ratio of the fiber of such a cross section exceeds 10%. The product was judged not to have adequate performance as a hollow fiber.
The matte effect was evaluated by measuring the light transmittance of a single fiber.

(Measurement method of single fiber light transmittance)
Using a metal system microscope manufactured by Olympus Corporation, the light transmittance of the sample fiber was measured and evaluated at two points for each of the five single fibers, for a total of 10 points. The magnification of the objective lens was 50 times, and the measurement area was φ = 20 μm. The light source was a transmission / bright field / halogen lamp, and measurement was performed in the range of 580 to 600 nm. The average of the transmittance at these wavelengths was taken as the light transmittance of the sample.

(Measurement of liquid content and solvent content)
About 2 g of the fiber to be measured was immersed in 200 g of pure water, and the solvent in the fiber was eluted by boiling at 95 ° C. for 30 minutes using a reflux condenser. Thereafter, the immersed fiber was taken out, dried at 110 ° C. for 2 hours, and the weight of the fiber was measured. On the other hand, the solvent concentration in the solution from which the solvent was eluted was measured by Shimadzu Corporation gas chromatography (GC-14B). The fiber weight before immersion was Fw, the fiber weight after drying was Fd, and the solvent concentration in the solution was measured by gas chromatography.
Liquid content (%) = [(Fw−Fd) / Fd] × 100
Solvent content (%) = [C × (200 + Fw−Fd) / Fd] × 100.

Example 1
A spinning stock solution (spinning stock solution A) prepared by dissolving an acrylonitrile-based copolymer of acrylonitrile / vinyl chloride / sodium styrenesulfonate = 49.5 / 50 / 0.5 in acetone to a polymer concentration of 29%, Is spun into a coagulation bath of acetone / water = 30/70, 20 ° C. through a nozzle having a hole shape of 50 holes each having four 0.14 mm circles, and then acetone / water = 25/75, 25 ° C. It was passed through a bath and stretched 1.5 times here. Furthermore, after passing through a 40 degreeC water-washing bath, it passed through 75 degreeC hot water, and stretched twice here. The liquid content at this stage was 95% by weight, and the acetone content was 9% by weight. Next, low-temperature drying at 40 ° C. was performed for 7 minutes, thereby reducing the liquid content to 20% by weight and the acetone content to 5%. Thereafter, the fiber was allowed to stay in a 160 ° C. dry heat treatment step for 10 seconds, and water and acetone were expanded and volatilized to develop a hollow portion. Thereafter, the film was further stretched twice at 130 ° C. and heat-treated at 145 ° C. The obtained fiber was 22 dtex of major axis / minor axis = 4/1, the hollowing rate was 92%, and the light transmittance was 60%.

(Example 2)
The spinning dope A of Example 1 was spun by the same method as in Example 1 in which four ellipses having a major axis / minor axis = 1.5 / 1 (major axis = 0.15 mm) were connected, and after low temperature drying The liquid content was reduced to 20% by weight and the acetone content to 4%. Thereafter, hollowing treatment and stretching heat treatment were performed, and the obtained fiber was 20 dtex of major axis / minor axis = 5/1, the hollowing rate was 90%, and the light transmittance was 64%.

(Example 3)
The spinning dope A of Example 1 was spun into a coagulation bath of acetone / water = 30/70, 20 ° C. through a nozzle having a hole number of 50 in which four circles having a diameter of 0.14 mm were connected, and then acetone. / Water = 35/65, passed through a 25 ° C. bath, where the film was stretched twice. Furthermore, after passing through a 40 degreeC water-washing bath, it passed through 75 degreeC hot water, and stretched twice here. The liquid content at this stage was 87% by weight, and the acetone content was 7% by weight. Next, low-temperature drying at 40 ° C. was performed for 6 minutes, thereby reducing the liquid content to 18% by weight and the acetone content to 4%. Thereafter, the fiber was allowed to stay in a 160 ° C. dry heat treatment step for 10 seconds, and water and acetone were expanded and volatilized to develop a hollow portion. Thereafter, the film was further stretched 1.5 times at 130 ° C. and heat-treated at 145 ° C. The obtained fiber had 22 dtex of major axis / minor axis = 4/1, the hollowing ratio was 89%, and the light transmittance was 62%.

Example 4
A spinning stock solution (spinning stock solution B) prepared by dissolving an acrylonitrile-based copolymer of acrylonitrile / vinylidene chloride / sodium styrenesulfonate = 50.0 / 490 / 1.0 in acetone so as to have a polymer concentration of 30%, Was spun into a coagulation bath of acetone / water = 30/70, 20 ° C. through a nozzle having a hole shape of 50 holes each having four 0.14 mm circles, and then acetone / water = 30/70, 25 ° C. It was passed through a bath and stretched 1.5 times here. Furthermore, after passing through a 40 degreeC water-washing bath, it passed through 75 degreeC hot water, and stretched twice here.
Further, it was passed through saturated steam at 96 ° C. for 2 minutes, and the liquid content at this stage was 103% by weight and the acetone content was 2% by weight. Next, low-temperature drying at 40 ° C. was performed for 6 minutes to reduce the liquid content to 21% by weight and the acetone content to 1%. Thereafter, the fiber was allowed to stay in a dry heat treatment step at 165 ° C. for 10 seconds, and water and acetone were expanded and volatilized to develop a hollow portion. Thereafter, the film was further stretched 1.5 times at 135 ° C. and heat-treated at 150 ° C. The obtained fiber had 22 dtex of major axis / minor axis = 4/1, the hollowing ratio was 95%, and the light transmittance was 57%.

(Example 5)
The spinning dope B of Example 4 was spun into a coagulation bath of acetone / water = 30/70, 20 ° C. through a nozzle having a hole number of 150 in which five circles having a diameter of 0.08 mm were connected, and then acetone. / Water = 30/70, passed through a 25 ° C. bath, and stretched 1.5 times here. Furthermore, after passing through a 40 degreeC water-washing bath, it passed through 75 degreeC hot water, and stretched twice here. Further, it was passed through saturated steam at 96 ° C. for 2 minutes. At this stage, the liquid content was 92% by weight and the acetone content was 2% by weight. Next, low-temperature drying at 40 ° C. was performed for 6 minutes to reduce the liquid content to 16% by weight and the acetone content to 1%. Thereafter, the fiber was allowed to stay in a dry heat treatment step at 165 ° C. for 10 seconds, and water and acetone were expanded and volatilized to develop a hollow portion. Thereafter, the film was further stretched 1.5 times at 135 ° C. and heat-treated at 150 ° C. The obtained fiber had 10 dtex of major axis / minor axis = 5/1, the hollowing ratio was 93%, and the light transmittance was 66%.

(Comparative Example 1)
Spinning stock solution A of Example 1 was spun by the same method as in Example 1 with the major axis / minor axis = 8/1 (major axis = 0.66 mm), and the liquid content after low-temperature drying was 15% by weight. The acetone content was reduced to 4%. Thereafter, the hollowing treatment was performed at 160 ° C., but the hollow portion was ruptured, and most of the cross-sections did not remain flat. Thereafter, a drawing heat treatment was performed, but the cross-section that did not retain the flat shape was also large in the final fiber, and the existence ratio of the fiber in which the hollow portion was ruptured was 55%, and the light transmittance was 60%.

(Comparative Example 2)
Spinning stock solution A of Example 1 was spun by the same method as in Example 1 with the major axis / minor axis = 8/1 (major axis = 0.66 mm), and the liquid content after low-temperature drying was 5% by weight. The acetone content was reduced to 2%. Thereafter, hollowing treatment was performed at 160 ° C., but the hollowing rate was as low as 27% and the light transmittance was 81%.

  Table 1 shows the obtained hollowing ratio, light transmittance, and the existence ratio of the cross-section where the hollow portion was ruptured.

Claims (1)

Spinning stock solution of acrylonitrile polymer is spun using a spinneret having holes in which at least one kind selected from circle, ellipse and rhombus is connected, and the major / minor axis of the fiber cross section is A hollow acrylic synthetic fiber having a cross section of 3 or more and a hollow part, wherein the light transmittance of a single fiber at 580 nm to 600 nm is 70% or less.

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