JPS628550B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a fibrous structure containing two or more types of polyester fibers having different apparent weight loss rates due to alkali treatment.

By treating a polyester fiber structure with alkali, it is possible to increase the interfiber voids and develop a soft and good texture with a silky feel.
Already known.

However, in fiber structures containing two or more types of polyester fibers that differ in their apparent weight loss rates due to alkali treatment, the strength of one of the fibers decreases excessively, making it impossible to obtain a satisfactory product. In particular, when the fibers with a high apparent weight loss rate are 0.3 denier or less, the ultrafine threads may even be completely dissolved by alkali treatment.

In response to this, it has been considered to treat fibers with a high apparent weight loss rate while protecting them with components that are not easily attacked by alkali, but contrary to expectations, sufficient effects were not obtained. For example, an attempt has been made to reduce the sheath component of a fabric with an alkali before eluting the sheath component of a fabric consisting of a single-core or multi-core sheath fiber having an ultra-fine polyester core and a polystyrene sheath, and a polyester of normal fineness. The strength of ultrafine fibers is extremely reduced. As a result of intensive study on this problem, the inventor of the present invention found that the cause of the decrease in strength was due to a defect in the sheath component that occurred during the spinning and fabric-making processes of the core-sheath fiber, and arrived at the following invention. . In other words, the present invention proposes that the apparent weight loss rate of single-core or multi-core core-sheath type fibers, in which the core component is made of polyester and the sheath component is made of a component that is not easily attacked by alkali, and the apparent weight loss rate after alkali treatment is A fiber structure is formed using polyester fibers smaller than the core component fibers, and when performing alkali treatment before removing the sheath component of the core-sheath type fiber, the core component fiber is heated above the softening point of the sheath component in advance. 1. A method for treating a polyester fiber structure, which comprises heat treating at a temperature below the melting point of the component polyester.

The present invention will be explained in more detail below.

In the present invention, the core component polyester and polyester fibers include polyesters such as polyethylene terephthalate and polybutylene terephthalate, and modified polyesters that have been dyed easily, cationically dyed, acidically dyed, antistatic, water-absorbent, etc. Refers to quality polyester.

The alkali-resistant component used as the sheath component refers to a component that is not itself decomposed or dissolved by alkali and at the same time is not easily permeable to alkali, and includes polystyrene, polyolefin, and copolymers thereof.

Apparent weight loss rate is measured by measuring the weight loss rate when treated in a 3% caustic soda boiling aqueous solution for a specified period of time.
A graph is created with time on the horizontal axis and weight loss rate on the vertical axis, and the weight loss rate up to 20% is expressed by the slope of the straight line when it is approximated by the least squares method. Generally, the apparent rate of weight loss is expressed by Equation 1 since it is a straight line up to a weight loss rate of 20%.

V=ΔW/t...Equation V: Apparent weight loss rate (sec ^-1 ) ΔW: Fiber weight loss rate (%) t: Treatment time (sec) The slow rate of alkali weight loss is generally expressed by the formula This is indicated by the alkali dissolution rate constant, which is different from the apparent weight loss rate used in the present invention. In other words, if the polymer constituting the fiber, the spinning method, and the alkali treatment conditions are the same, the alkali dissolution rate constant will be constant, but even if they are the same, the apparent weight loss rate will change if the fineness differs. do. For example, if the fineness increases four times, the fiber surface area will be halved, so the apparent weight loss rate will be
It becomes 1/2.

In other words, the general rate of weight loss is determined by the following equation.

R: Undissolved weight fraction after t sec (%) D: Denier t: Processing time (sec) k: Alkali dissolution rate constant (cm/sec) Also, if the polymers constituting the fibers and the single fiber fineness are the same Even if the yarn spinning method is different, the apparent weight loss rate will change. That is, the apparent weight loss rate of the fineness obtained by removing the sheath of a core-sheath type composite fiber is higher than that of the fiber obtained by normal yarn spinning even if the constituent polymer and single fiber fineness are the same.

The fiber structure refers to the form of woven fabric, knitted fabric, non-woven fabric, etc., and its constituent fibers include single-core or multi-core core-sheath type, where the core component is made of polyester and the sheath component is made of a component that is not easily attacked by alkali. It is sufficient that at least 10% of the fibers and polyester fibers whose apparent weight loss rate due to alkali treatment is smaller than that of the core fiber after removal of the sheath component are contained. Even if it contains synthetic fibers with different weight loss rates such as polyester fibers, polyamide fibers, and polyolefin fibers, natural fibers such as cotton, silk, and wool, semi-synthetic fibers such as acetate, and regenerated fibers such as rayon. good. In addition to these fibers, resins, adhesives, sizing agents, etc. can be impregnated,
This also includes those applied by means such as coating or spraying.

As a method for removing the sheath component, for example, when a polystyrene polymer is used, various aromatic hydrocarbons, chlorinated hydrocarbons, and other various organic solvents that do not dissolve the polyester can be used.

Alkaline treatment is a process in which polyester is hydrolyzed using so-called alkaline compounds such as caustic soda and caustic potash, and alkaline compounds such as soda carbonate and potassium carbonate, and any method may be used as long as polyester can be hydrolyzed. .

One of the points of the present invention is to use a core-sheath type fiber as described above and to perform an alkali treatment before removing the sheath component. That is, the core fiber is protected from alkali by the sheath component, and the other polyester fiber is subjected to alkali weight reduction treatment. However, there is no problem if the core fiber is completely protected by the sheath component, but in reality, many cracks occur in the sheath component during spinning and subsequent processes, such as weaving, knitting, and weaving, to create a fiber structure. As a result of this, alkali enters through the cracks and the apparent weight loss rate of the core fiber is high, causing the fiber to undergo partial alkaline hydrolysis and local embrittlement.

Therefore, an important point of the present invention is to perform heat treatment at a temperature higher than the softening point of the sheath component and lower than the melting point of the core component polyester before the alkali treatment. That is, such heat treatment has the effect of causing the sheath component to flow and eliminating the aforementioned cracks. Therefore, if the temperature is below the softening point of the sheath component, the effect of sealing cracks cannot be expected, and if the temperature is above the melting point of the core component, the core-sheath type fiber will not retain its form as a fiber. Heat treatment is required. In addition, the softening point as used in the present invention is the temperature at which the polymer starts to flow, and if it has a clear melting point, it coincides with the melting point.

Next, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Two 5-ply satin fabrics were made using the following yarns.

(1) Warp: 150 denier, 48 filament polyethylene terephthalate processed yarn.

(2) Weft: 245 denier, 40 filament multicore sheath type fiber. The number of cores is 36 cores/filament, the core component is polyethylene terephthalate with a melting point of 255℃, the sheath component is polystyrene with a softening point of 120℃, and the ratio of the sheath component is 20%. The apparent weight loss rate of the core fibers after removing the sheath component is 14 times that of the warp yarns.

This fabric is subjected to normal Relax scouring treatment (95℃).
One row was treated as it was, the other one was dry heat treated at 150℃, and the weight ratio to the fabric was reduced by alkali treatment.
Achieved a 10% weight loss. After removing the sheath component with trichlene, the dyeing finish was carried out using a conventional method.

The weft strength of products subjected to dry heat treatment at 150℃ is
810g/multifilament (strength of over 4.1g/d), whereas the weft strength of the product without dry heat treatment is only 390g/multifilament (strength of just under 2.0g/d), which is less than half that, and there is no fuzz. It was done.

Example 2 A twill fabric was made using the following yarns.

(1) Warp: 150 denier, 72 filament polyethylene terephthalate yarn.

(2) Weft: 200 denier, 24 filament multicore sheath type fiber. The number of cores is 3 cores/1 filament.
The core component is polyethylene terephthalate copolymerized with 3.8% by weight of 5-sodium sulfoisophthalate with a melting point of 230°C, the sheath component is polystyrene with a softening point of 105°C, and the ratio of the sheath component is 25%. The apparent weight loss rate of the core fiber after removing the sheath component is approximately 10% of the warp.
It's double.

This fabric is subjected to normal Relax scouring treatment (95℃).
was applied, dry heat treated at 160°C, and alkali treated to reduce the weight of the fabric by 15%. After removing the sheath component with trichlene, the dyeing finish was carried out using a conventional method.

For comparison, 3.8% of 150 denier, 72 filament 5-sodium sulfoisophthalate was used in the weft.
Using a polyethylene terephthalate yarn copolymerized in weight percent, a woven fabric with the same structure and density was subjected to the same treatment to reduce the weight by 15%, and then dyed and finished using a conventional method.

While the weft strength according to the present invention is 4.0 g/d,
The weft strength by the comparative method was only 1.5 g/d.

Claims (1)

[Scope of Claims] 1 A single-core or multi-core core-sheath type fiber whose core component is made of polyester and whose sheath component is made of a component that is not easily attacked by alkali, and whose apparent weight loss rate by alkali treatment is determined by the removal of the sheath component. A fiber structure is formed using polyester fibers smaller than the core component fibers, and when performing an alkali treatment before removing the sheath component of the core-sheath type fiber, the sheath component is heated at a temperature higher than the softening point of the sheath component in advance. . A method for treating a polyester fiber structure, the method comprising heat treating at a temperature below the melting point of the core component polyester. 2. The method for treating a polyester fiber structure according to claim 1, wherein the single fiber fineness of the core component is 1.0 denier or less.