JPH06128815A - Polyester conjugated fiber - Google Patents

Abstract

PURPOSE:To provide a polyester fiber exhibiting a relatively large fineness and excellent in pill resistance. CONSTITUTION:This sheath-core type polyester conjugated fiber is a staple fiber produced by applying an alkaline hydrolysis treatment to a polyester conjugated staple fiber composed of a readily hydrolyzable core part of a polyester component composed mainly of ethylene terephthalate unit and a scarcely hydrolyzable sheath part of a polyester component substantiously composed of ethylene terephthalate unit and surrounding the core part. The single fiber strength after the alkaline treatment is 3.6 to 4.2g and the elongation is 8 to 12%. The core part is not hollow and an excellent pilling resistance is exhibited. The fiber length of this fiber and the ratio of the core part to the sheath part are more preferably <=85mm and (core/sheath) =(4/1) to (1/4) respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core-sheath type polyester composite fiber having excellent anti-pilling property, and in particular, the inside of the fiber is largely hydrolyzed by an alkali hydrolysis treatment but becomes a macaroni-like hollow state. The present invention relates to a polyester composite fiber which is solid and solid in a solid state and has excellent pilling resistance.

[0002]

2. Description of the Related Art Polyester fibers, especially polyester fibers mainly composed of polyethylene terephthalate, are widely used for clothing, industrial materials, interiors, etc. due to their excellent performance. However, depending on the application, there is a problem that pilling occurs due to the high strength which is an inherent property of polyester, and this pilling has a drawback that the appearance is significantly impaired. In order to improve this drawback, for example, JP-A-50-135331 and JP-A-6-135331.
As described in JP-A-1-47818, a polyester in which a phosphate ester bond is copolymerized is prepared, and this is subjected to hot water treatment after fiberizing to reduce the strength of the fiber, and the anti-pilling property (hereinafter simply referred to as anti-pill property Abbreviated), or as shown in JP-B-58-18447, a phosphorus-containing polyester fiber to which a specific amount of a phosphorus compound is added and which has a specific intrinsic viscosity is prepared. In order to impart anti-pill property by doing so, a polyester fiber to which a phosphorus compound is added or copolymerized is produced, and this is subjected to hot water treatment to reduce its strength to provide anti-pill property. However, these techniques have a problem that it is extremely difficult to balance the anti-pill property and abrasion resistance of the polyester fiber from the viewpoint of their production and their products. And the root of this problem is based on the idea that a polyester component added or copolymerized with a phosphorus compound must be used as a 100% homo component of the fiber or as a surface component of the fiber, It must be said that industrially overcoming the above problems is extremely difficult for fibers based on this concept.

The anti-pill-formed polyester fibers that have been proposed so far have a monofilament fineness of 2 at most.
No anti-pillified polyester fiber having a fineness higher than that of denier (dr) has been proposed.

[0004]

The problems of the present invention are as follows:
The purpose is to obtain a polyester fiber having a relatively large fineness of about 3 dr and excellent anti-pill performance.

[0005]

Means for Solving the Problems The present inventors have diligently studied the above-mentioned problems, and have used a polyester component which is easily hydrolyzed by an alkali hydrolysis treatment and a polyester component which is hardly hydrolyzed by the treatment, Moreover, if the former component is a composite fiber having the core component and the latter component is the sheath component, and the composite fiber is cut into a short fiber shape and subjected to the hydrolysis treatment, the core component of the fiber is hydrolyzed from the cut end surface. Although it becomes a component with reduced strength, it does not become a macaroni-like so-called hollow state, but the core component becomes a solid state in which the intrinsic viscosity [η] is 0.30 or less in a low viscosity and low strength state. The rest of the fiber is a core-sheath non-hollow fiber as a whole, but the strength is reduced, and it was surprisingly found that this fiber is a fiber excellent in anti-pill formation. Single fiber strength is 3.6~4.2g core-sheath non hollow fibers obtained by the solution process, elongation 8% to 12%
It has been found that the above-mentioned problems can be achieved by using a fiber that falls within the range. That is, the present invention is
"A core composed of a polyester component mainly composed of ethylene terephthalate units, which is susceptible to hydrolysis, and a sheath part surrounding the core, which is composed of a polyester component substantially composed of ethylene terephthalate units, which is resistant to hydrolysis. Which is a polyester conjugate fiber having a tenacity of single fiber after alkali treatment of 3.6 to 4.2 g, an elongation of 8 to 12% and a non-hollow core portion, and excellent core-sheath polyester conjugate fiber It is. "

In the present invention, the component to be hydrolyzed by the alkali treatment is positioned inside the fiber, and the component positioned inside the fiber is hydrolyzed to reduce its strength. It is unclear whether or not it will be an anti-pill, but the above treatment results in a single fiber tenacity of 3.6 to 4.2 g and an elongation of 8 to 12%, which results in a relatively large fineness. This is the realization of anti-pill-formed fiber.

Conventionally, as an anti-pilling fiber of a polyester fiber for clothing, it has been usual to consist of 100% of a polyester component having an anti-pilling property, and therefore, the fiber fineness thereof is around 1.5 dr, at most about 2 dr. Therefore, as in the present invention, the anti-pill in the relatively large fineness fiber in the core-sheath composite fiber having the fineness and the hydrolysis of the core component among the core-sheath components is performed. No chemical fiber has hitherto been known. Furthermore, the fiber of the present invention is a component that is hydrolyzed by alkali treatment, since it is a fiber located in the core portion of the core-sheath component, like ordinary polyester fibers, the production of the fiber is easy, It has a great feature that its operation is easy in the industrial manufacturing method. That is, due to the fiber structure in which the component to be hydrolyzed is located, and not the manufactured long fiber state, the core component is hydrolyzed only after it is cut into the short fiber state and then alkali-treated. Since it is a different fiber, the manufacturing process of the fiber and the higher-order processing steps such as spinning, weaving, and knitting can be manufactured and processed exactly like ordinary polyester fibers, and the woven fabric near the final step of the processing,
The final product is produced by first hydrolyzing the inside of the fibers constituting the woven or knitted product by treating the knitted product with an alkali.

The fiber of the present invention is not a hollow fiber, but its core part undergoes hydrolysis treatment and its intrinsic viscosity [η] is 0.30.
The following low-viscosity and low-strength state is achieved, and thus such a relatively thick fine fiber having anti-pill properties is suitable, for example, as a material for uniforms and as a material for knits.

In the conjugate fiber of the present invention, if the single fiber strength and elongation are below the lower limits of the above ranges, respectively,
It is inconvenient because it becomes weak in terms of wear strength as a material, and when it is above the upper limit, the effect of anti-pill formation is not exhibited, and in this case it is also inconvenient.

The composite fiber of the present invention can be obtained as follows. First, the polyester that constitutes the core component is preferably a polyester that contains 0.5 to 1.5 mol% of phosphorus atoms with respect to the total acid component. When the phosphorus content is less than 0.5 mol%, the hydrolysis by the alkaline hydrolysis treatment in the latter stage does not sufficiently occur, and the strength of the core component cannot be reduced. On the other hand, if the content exceeds 1.5 mol%, the spinnability becomes poor.

The intrinsic viscosity of the polyester constituting the core component is preferably 0.38 to 0.53. If the intrinsic viscosity is lower than 0.38, composite spinning is difficult, and if the intrinsic viscosity exceeds 0.53, hydrolysis is not sufficiently caused by the alkali treatment in the latter stage, so that the strength is reduced by the hydrolysis. I can't.

The method of introducing a phosphorus atom into the polyester molecule can be achieved, for example, by adding the phosphorus compound represented by the following chemical formula 1 at the stage of polyester polymerization.

[0013]

[Chemical 1]

On the other hand, the polyester constituting the sheath component of the composite fiber in the present invention is a polyester substantially composed of ethylene terephthalate units, and polyethylene terephthalate is preferably used. However, there is no problem in containing a small amount of the copolymerization component within the range not impairing the object of the present invention.

The composite ratio of the sheath component and the core component is
Core / sheath = 4/1 to 1/4 is preferable, and 2/1 to 1/2 is more preferable. Outside this range,
It is difficult to adjust the core-sheath ratio at the time of spinning the composite fiber, and the processability during drawing is significantly deteriorated. Further, if the ratio of the core component is low, the effect of alkali treatment cannot be exhibited.

Fibers composed of both components are subjected to composite spinning according to a conventionally known method, stretched and heat-treated as required, and the intrinsic viscosity of the core component polyester is adjusted to 0.
38-0.53 composite fiber is obtained, and this is cut into short fibers to be used as raw material fibers. The intrinsic viscosity of the core component is preferably in the above range. If it is lower than the lower limit, the spinning cannot be smoothly carried out, and even if it exceeds the upper limit, sufficient hydrolysis cannot be carried out in the subsequent alkali treatment and strength cannot be lowered.

The fibers in the present invention are preferably fibers cut to 85 mm or less, more preferably 64 mm or less. If the cutting length is longer than 85 mm, the penetration of alkali from both cutting edges to the central part will be insufficient, and the desired strength and elongation will not be obtained after alkali treatment, so the anti-pill property expected finally And fiber properties cannot be obtained.

The polyester short fibers thus obtained are
After making it into a woven or knitted fabric as a spun yarn, it is dyed, and then the alkali hydrolysis treatment is performed to reduce the strength of the fiber core component,
A woven or knitted product using the conjugate fiber of the present invention can be obtained.
Depending on the purpose, the short fibers are not woven or knitted,
It is also possible to make a nonwoven fabric and to carry out alkaline hydrolysis treatment as described above to obtain a nonwoven fabric using the conjugate fiber of the present invention. Further, the above steps do not limit the order of the steps, and it goes without saying that, for example, alkali hydrolysis treatment may be carried out before dyeing treatment.

Alkali compounds used in the alkaline hydrolysis treatment include sodium hydroxide, potassium hydroxide,
Examples thereof include tetramethylammonium hydroxide, sodium carbonate, potassium carbonate and the like. Of these, sodium hydroxide and potassium hydroxide are particularly preferable.
In addition, an alkali weight loss accelerator can be appropriately used.

The aqueous solution concentration of the alkaline compound varies depending on the type of the alkaline compound and the treatment method, but is usually 0.01.
-40% by weight, especially 0.1-30% by weight
Is preferred. The treatment temperature is usually in the range of 90 to 120 ° C., and the treatment time is usually in the range of 30 to 60 minutes.

A matting agent, a flame retardant, a deodorant, an antibacterial agent, and an aromatic agent are provided on at least one of the core and the sheath of the composite fiber of the present invention.
Of course, a far-infrared radiation substance or the like may be appropriately added depending on the application.

Furthermore, in the conjugate fiber of the present invention,
The cross-sectional shape of the fiber is not limited to the concentric circular shape, and of course, even if the core portion has an eccentric shape with an offset,
Alternatively, instead of being circular, the shapes may be various shapes, and these composite shapes can be easily manufactured by the heretofore known manufacturing techniques.

[0023]

The present invention will be described in more detail with reference to the following examples. In addition, in the present invention and the following examples, the intrinsic viscosity means a value (unit: dl / g) measured at 30 ° C. by using an equivalent weight mixed solvent of phenol and tetrachloroethane. In addition, the pilling test for textiles is JIS-
According to Method A of 1076 (1978).

Example 1 As a polyester used as the core component of the core-sheath composite component, di-n-butyl phosphate was used as a phosphorus atom in the polymerization reaction system in the production thereof in an amount of 1.0 mol% with respect to the total acid component. Was added to prepare a polyester mainly composed of ethylene terephthalate and having an intrinsic viscosity [η] = 0.50. As the polyester used as the sheath component, a polyester essentially composed of ethylene terephthalate and having an intrinsic viscosity [η] = 0.68 was prepared. Using both of these polyesters, a spinning temperature of 285 ° C. and a discharge rate of 300 g / mi were measured by a known composite melt spinning device.
An undrawn yarn was obtained under the conditions of n, core / sheath ratio = 1/1, and winding speed of 900 m / min. The unstretched yarn is bundled, stretched 3.5 times, then mechanically crimped with a crimper, heat-treated and cut into 51 mm to obtain a single fiber fineness of 2.0 d.
r core-sheath composite short fibers of r were obtained. This fiber had a single fiber strength of 7.0 g and an elongation of 20.0%. This short fiber 100
A plain woven fabric was prepared by using this spun yarn as a spun yarn used in%. Thereafter, this was treated in a 30 g / l sodium hydroxide aqueous solution at 95 ° C. for 30 minutes to obtain an alkali-hydrolysis-treated fabric. The fibers of the cloth after the alkali treatment maintain the composite state in which the core portion is clogged, but the [η] of the core portion has a low strength of 0.30 or less,
As the core-sheath composite fiber, the single fiber strength was 4.0 g and the elongation was 9.5%. The result of the pilling test of this fabric was excellent, that is, grade 4. By the way, the pilling property of the cloth before the alkali treatment was grade 1.

Comparative Example 1: The plain woven fabric prepared in Example 1 was treated with the same 30 g / l sodium hydroxide aqueous solution at 95 ° C. for 10 minutes, which was shorter than that of Example 1, to give an alkali-treated cloth. Obtained. The result of the pilling test of this fabric is the second grade, and the single fiber strength of the fiber is 5.2 g,
The elongation is 14.0%, indicating that the alkali hydrolysis treatment is insufficient.

Comparative Example 2 The plain woven fabric prepared in Example 1 was treated with the same 30 g / l sodium hydroxide aqueous solution at 95 ° C. for 80 minutes longer than that of Example 1 to give an alkali treated cloth. Obtained. The result of the pilling test of this fabric was grade 5, and the pilling property was good, but the single fiber strength of the fiber was 3.4 g and the elongation was 6.8%, which was an insufficient wear strength property. It turns out that

Example 2 A combination of the polymers used in Example 1 with a phosphorus content of 1.2 mol% as the polyester of the core component was used, and the core / sheath ratio was 6/4. Single fiber fineness 2dr, length 5 which consists of composite fiber
A 1 mm short fiber was made. This short fiber is used as a spun yarn, and this is made into a tubular knitted fabric having a basis weight of 80 g / m ²
Alkaline hydrolysis treatment was performed for 30 minutes. The result of the pilling test of the obtained knitted fabric was grade 5, and the pilling property was good. The single fiber strength of the fibers constituting the knitted fabric was 3.8 g, and the elongation was 9.8%. By the way, the pilling property of the cloth before alkaline hydrolysis treatment is 1
It was class.

Example 3: Using the same polyester polymer used in Example 2, a short fiber having a single fiber fineness of 2 dr and a length of 51 mm made of a composite fiber having a core / sheath ratio of 3/7 was prepared. This short fiber is used as a spun yarn, and this is weighted 8
A tubular knitted fabric of 0 g / m ² was subjected to alkali hydrolysis treatment at 95 ° C. for 30 minutes. The knitted fabric thus obtained had a pilling test result of 4, showing good pilling properties. The fibers of the knitted fabric had a single fiber tenacity of 3.8 g and an elongation of 8.2%.

Comparative Example 3 In producing a polyester in the same manner as in Example 1, a phosphorus compound was added as polyester for the core component so that the phosphorus atom content was 1 mol% with respect to the total acid component [η ] = 0.55 polyester was made. On the other hand, as the polyester for the sheath component, it consists essentially of polyethylene terephthalate [η] = 0.6
I made 8 polyester. Using these polyesters, short fibers made of core-sheath composite fibers having a single fiber fineness of 2.0 dr and a cut length of 51 mm were obtained by the same method as in Example 1. This fiber had a single fiber tenacity of 7.4 g and an elongation of 21%. This short fiber was used as a spun yarn to prepare a plain woven fabric. This was subjected to alkaline hydrolysis treatment under the same conditions as in Example 1. The single fiber strength of the fibers of the cloth after this alkaline hydrolysis treatment is 4.6.
g, and the elongation was 13%. The result of the pilling test of this fabric was grade 2. From this, even if the intrinsic viscosity of the polymer used for the core is too high, it becomes difficult to perform the treatment by appropriate alkali hydrolysis, so that the intrinsic viscosity of the core polymer before the hydrolysis treatment is [η] = 0.38 to It turns out that 0.53 is desirable.

[0030]

INDUSTRIAL APPLICABILITY As described above, the present invention is a polyester fiber having a relatively large fineness, excellent anti-pill performance and easy to produce, and is useful as a fiber that can open up new uses of the polyester fiber. is there.

Claims (4)

[Claims] 1. A core portion composed of a polyester component mainly composed of ethylene terephthalate units and susceptible to hydrolysis, and a sheath surrounding the core portion and composed of a polyester component substantially composed of ethylene terephthalate units and resistant to hydrolysis. A polyester composite fiber composed of 10 parts and a single fiber strength after alkali treatment of 3.6 to 4.2 g,
A core-sheath polyester composite fiber having an elongation of 8 to 12% and a non-hollow core portion and excellent anti-pilling properties. 2. The fiber according to claim 1, wherein the fiber length is 85 m.
A core-sheath polyester composite fiber having a length of m or less. 3. The core-sheath polyester composite fiber according to claim 1, wherein the composite ratio of the core portion and the sheath portion is core / sheath = 4/1 to 1/4. 4. The fiber before hydrolysis treatment according to claim 1, wherein the core component constituting the core portion which is susceptible to hydrolysis contains 0.5 to 1.5 mol% of phosphorus atom with respect to the total acid component. A core-sheath polyester composite fiber which is a polyester having an intrinsic viscosity of 0.38 to 0.53.