JPH062221A - Method for producing splittable conjugate fiber and ultrafine polyester fiber - Google Patents

Abstract

(57) [Summary] [Object] To provide a splittable conjugate fiber which has a good process passability before the splitting process and which can be easily split into fine fibers during the splitting process. [Structure] One component A of the splittable conjugate fiber has a melt viscosity of 3500 to 12000 under a zero shear stress at 280 ° C.
It is composed of a poise polyester and polyoxyalkylene glycols (10 to 50 wt% with respect to the polyester), and the other component B is a polyester having a melt viscosity of 300 to 2,500 poise. At least one of A and B is the other. A splittable conjugate fiber that is split and arranged in multiple layers. [Effect] Since polyalkylene glycols are blended in one component, coexistence of water causes water swelling to generate strain in the joint surface with the other component, which facilitates division by mechanical impact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a splittable conjugate fiber in which at least one of two types of polyester is split and arranged in multiple layers. More specifically, the present invention relates to a composite fiber in which one component is mixed with a polyalkylene glycol and which can be easily peeled and separated by applying mechanical stress in the presence of water, and a method for producing an ultrafine polyester fiber using the same.

[0002]

2. Description of the Related Art Generally, non-woven fabrics using fine fibers
It is well known that the fabric has a soft texture,
Many proposals have been made as methods for obtaining such ultrafine fibers. The most useful method is a method of forming a sea-island fiber with two or more kinds of polymers having different solubilities (in a solvent or an acid or an alkaline solution), and dissolving and removing sea components to obtain ultrafine fibers. However, in such a method, a solvent treatment step and a solvent recovery step are required, and there are drawbacks that the process becomes complicated, and the cost is disadvantageous.

As another method, a composite fiber composed of polymers having no affinity for each other, for example, polyester / polyamide, polyester / polyolefin, polyamide / polyolefin, etc., is subjected to mechanical shock such as puffing, needle punching, high-pressure water treatment and the like. A method of forming ultrafine fibers by the method described above is proposed in JP-A-62-133164.

However, since the composite fiber obtained by such a method has a poor affinity between polymers, there is a problem that component cracking occurs when the web is formed by passing through the card process, resulting in a marked decrease in productivity. . Further, polyamide or polyolefin is usually used as one component, but these are inferior in light resistance / weather resistance, and the resulting ultrafine fibers are composed of two kinds of polymers, which complicates the dyeing process and also makes use of products such as nonwoven fabrics. There is a problem of being limited.

Another method is Japanese Patent Publication No. Sho 61-1975.
No. 6 discloses that one component of a composite fiber is mixed with polyalkylene glycol, a high-pressure water stream is applied to a fiber product made of the composite fiber to crush and remove the component containing the polyalkylene glycol, and the other component is fibril. There has been proposed a method of forming (grouping ultrafine fibers). However, in such a method, the crushed polymer cannot be an effective fiber of the final product and is removed, which is disadvantageous in cost.
Further, there is a problem that the crushed polymer is not completely removed from the product and the quality is degraded.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and its object is to have a good card passage property and to divide it very easily by mechanical stress. It is an object of the present invention to provide a splittable conjugate fiber which is excellent in light resistance and weather resistance, can be easily dyed, etc., and can obtain an excellent fine fiber product, and a novel method for producing an ultrafine fiber using the same.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have determined that both components of the composite fiber are polyester and one is a polyester having a high melt viscosity (under 280 ° C.). It is presumed that when an alkylene glycol is blended, the additive migrates to the interface with the other polyester, and it is found that the additive can be easily divided by applying mechanical stress in the presence of water, and thus the present invention was reached. did.

That is, according to the present invention, 100 parts by weight of a polyester having a melt viscosity of 3500 to 12000 poise under a zero shear stress at 280 ° C. is mixed with 10 parts of a polyoxyalkylene glycol which is substantially non-reactive with the polyester. -50 parts by weight was used as one component A, and 2
Melt viscosity under zero shear stress at 80 ° C is 300 to 2
A splittable conjugate fiber comprising a 500-poise polyester as the other component B, wherein at least one of the components A and B is divided and arranged in multiple layers by the other component, and It is a method for producing an ultrafine polyester fiber in which such splittable conjugate fiber is subjected to a mechanical impact in the presence of water to be split into each component fiber.

Both components constituting the splittable conjugate fiber of the present invention are preferably polyesters from the viewpoint of light resistance and weather resistance of the ultrafine fibers after splitting. As the polyester preferably used, terephthalic acid, naphthalene dicarboxylic acid,
1,2-bis (4-carboxyphenoxy) ethane,
Examples of the fiber-forming polyester include 4,4'-diphenyldicarboxylic acid as an acid component and ethylene glycol, trimethylene glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol as a glycol component. A third component may be copolymerized with these polyesters to impart various functions, for example, 5-sodium sulfoisophthalic acid component, polyethylene glycol, polytetramethylene glycol, isophthalic acid, phthalic acid, adipic acid, sebacine. Any of the conventionally used copolymerization components such as acid, neopentyl glycol and diethylene glycol can be used. Among them, polyesters in which 80 mol% or more, particularly 90 mol% or more of repeating units are ethylene terephthalate or tetramethylene terephthalate are preferable. Incidentally, in the polyester, various additives within a range that does not impair the object of the present invention, for example, a fluorescent whitening agent, an ultraviolet absorber,
You may mix a stabilizer etc.

In the present invention, one component A of the composite fiber is used.
It is necessary that the polyester used in (1) has a melt viscosity at 280 ° C. under zero shear stress of 3500 to 12000 poise, preferably 3500 to 10000 poise. If it is less than 3500 poise, it is presumed that the polyalkylene glycols described below are less likely to migrate to the composite fiber-bonding interface, and it becomes difficult for the components to peel off due to mechanical impact, and the polyalkylene glycols are added. This lowers the melt viscosity and deteriorates the spinnability. On the other hand, if it exceeds 12,000 poise, it becomes difficult to produce polyester, which is not preferable.

In order to obtain a polyester having such a melt viscosity, a 5-sodium sulfoisophthalic acid component which copolymerizes the intrinsic viscosity of the polyester is usually copolymerized, and a trifunctional or higher polyfunctional ester-forming component is copolymerized. Alternatively, any method such as addition of a thickener may be adopted, but from the viewpoint of productivity, the method of increasing intrinsic viscosity or copolymerizing a 5-sodium sulfoisophthalic acid component is preferable.

The polyalkylene glycol compounded in the above polyester is 10 to 5 relative to the polyester.
It should be 0% by weight, preferably 10 to 30% by weight. If the blending amount is less than 10% by weight, it is considered that the adhesive force between the two components of the composite fiber increases, and even if the treatment described later is applied, it becomes difficult to separate and separate, and an ultrafine fiber cannot be obtained. On the other hand, when the amount exceeds 50% by weight, not only the melt viscosity of the component is greatly reduced to make stable spinning impossible but also the toughness of the component is reduced and the component is powdered when the treatment described below is performed. It is not preferable because it is easily crushed. In addition, the light resistance is also reduced.

Polyalkylene glycols preferably used include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene oxide / propylene oxide block or random copolymers, and these are alkyl groups, aryl groups, The terminal may be blocked with an acyl group or the like, or may be a block polyether ester or a block polyether amide obtained by reacting various glycol components or amine components and acid components. Among them, the one in which the end is blocked with an alkyl group is more preferable because it has good light resistance.

These polyalkylene glycols are
Although those having an average molecular weight of 3,000 to 250,000 can be used, those having an average molecular weight of 5,000 to 50,000 are more preferable in terms of availability. When it is less than 3,000, it reacts when it is mixed with polyester, and it becomes difficult for interfacial peeling from other components to occur, and the spinnability also deteriorates. On the other hand, those exceeding 250,000 have high costs because it is difficult to polymerize them by an inexpensive method.

The polyalkylene glycols may be added to the polyester by adding them at the time of polymerization of the polyester, or by melt-kneading the polyester chips and the polyalkylene glycols when the composite fibers are melt-spun. Any method such as a method of kneading the melted polyester and polyalkylene glycols before melt spinning can be adopted, but generally polyalkylene glycols have poor heat resistance, and melt spinning work is easy. From the point of view, it is desirable that the polyester chips and the polyalkylene glycols be mixed and then melt spun.

Next, the other component B constituting the splittable conjugate fiber
It is necessary that the polyester (1) has a melt viscosity of 300 to 2500 poise under zero shear stress at 280 ° C. If it is less than 300 poise, the melt viscosity is too low, the spinning tone is deteriorated, and the mechanical properties of the divided ultrafine fibers are insufficient, which is not preferable. On the other hand, when it exceeds 2500 poise, it becomes difficult to spin into a split type composite structure, which is not preferable.

On the other hand, it is desirable that the polyester of the other component B is substantially not blended with polyalkylene glycols, but may be blended in a small amount as long as the object of the present invention is not impaired. Further, when a polyester obtained by copolymerizing isophthalic acid and neopentyl glycol is used as either component A or component B, the difference in hot water shrinkage between the two components constituting the composite fiber becomes large, and the difference in mechanical stress causes It is preferable because division becomes easy.

In the conjugate fiber composed of the component A and the component B described above, at least one component must be divided and arranged in multiple layers by the other component, and the other divided component is buried in the one component. Those having no shape are preferable. Specific examples include those shown in FIGS. 1 (a) to 1 (e). Among them, those having a hollow in FIG. 1 (a) are effective in exerting mechanical stress to facilitate division,
Further, water penetration into the fiber is good, and the splittability is further improved, which is preferable.

In the splittable conjugate fiber of the present invention, it is desirable that the difference in heat shrinkage between the components when treated in boiling water for 20 minutes is 2% or more, preferably 5% or more. When the treatment condition described below is set to a high temperature, the composite fiber is subjected to interfacial strain between the components due to the difference in shrinkage between the components, and can be easily separated by the mechanical stress. Further, even in a portion where peeling and splitting due to mechanical stress does not occur, peeling and splitting progresses during dry heat treatment, and an ultrafine product of good quality can be obtained.

In order to obtain the splittable conjugate fiber of the present invention described above, a conventionally known method for producing splittable conjugate fiber may be employed as it is. For example, JP-B-39-29636 and JP-A-50- It can be easily obtained according to the yarn making method disclosed in Japanese Patent No. 5650.

In the present invention, the above-mentioned composite fiber is subjected to mechanical impact in the presence of water to give components A and B.
The space can be divided into ultrafine polyester fibers. When water is not substantially present, exfoliation and splitting between components is difficult to proceed even when mechanical stress is applied, and extremely large stress must be applied to achieve sufficient splitting. This is not preferable because the quality of the product is degraded. The higher the temperature of the water used here is, the more easily the separation due to stress becomes easier, which is more preferable.

The method of allowing water to exist is not particularly limited, and water may be adsorbed to the ultrafine fibers in advance before mechanical stress is applied, for example, by immersing in water, or at the same time when stress is applied. Water may be added. Specifically, for example, a card method from short fibers, a cross wrapper method, a random weber method or a method of needle punching after immersing a nonwoven fabric prepared by a nonwoven fabric forming method such as a spun bond method from long fiber filaments in water, Examples of the method include a method of water-needing a non-woven fabric with a high-pressure water stream without immersing it in water, and a method of dyeing and puffing after forming a fabric.

The splittable conjugate fiber of the present invention preferably has a fineness of the obtained ultrafine fibers of 0.5 to 20 denier within a range of 0.8 denier or less, and is subjected to mechanical impact. In the stage before separation and separation by peeling, particularly in the stage of yarn making, it is desirable to give as little moisture as possible, and when it is necessary to immerse in water, it is desirable to shorten the time as much as possible and dry it quickly.

[0024]

The reason why the splittable conjugate fiber of the present invention can be split very easily, although it is a conjugate fiber composed of polyester / polyester-like polymer system, is still unknown. . That is, since the polyalkylene glycols mixed with the polyester having a high melt viscosity have a large difference in melt viscosity from the polyester, the polyalkylene glycols segregate on the surface of the component A due to various stresses during spinning, and the polyalkylene glycols The adhesiveness with B is reduced. Further, the water treatment causes the polyalkylene glycols to swell by water absorption or elute and be removed, so that the joint surface between the components A and B is distorted, and as a result, splitting into ultrafine fibers by mechanical impact becomes extremely easy. It is estimated that

[0025]

INDUSTRIAL APPLICABILITY The conjugate fiber of the present invention passes through the process such that, in a process such as a card process and a non-woven fabric manufacturing process where water is not substantially attached, component cracking hardly occurs even when mechanical stress is applied. It is characterized by having good properties. Moreover, since the obtained conjugate fiber is different from the conventional one in that all components are made of polyester, it is easy to dye, has excellent light resistance and weather resistance, and has good heat resistance.

[0026]

The present invention will be described in more detail with reference to the following examples.

[0027]

Example 1 5-sodium sulfoisophthalic acid (SI
P) of 3.6 mol% and having an intrinsic viscosity of 0.5 and a melt viscosity of 600 at 280 ° C. under zero shear stress.
Molecular weight of 200 in 0 poise polyethylene terephthalate
Polyethylene glycol of 00 was added to the polyester in an amount of 15% as the component A, and the intrinsic viscosity was 0.6.
4. Polyethylene terephthalate having a melt viscosity of 2500 poises under zero shear stress at 280 ° C. of 4 was used as the B component, the component A: B weight ratio was 50:50, the spinneret temperature was 290 ° C., and the melt composite spinning was performed at 1150 m / min. After winding, a spun raw yarn having a cross section shown in FIG. 1 (a) was obtained.

The obtained spun raw yarn was heated in warm water at 70 ° C. to 3.
After stretching 5 times and re-stretching 1.05 times in 90 ° C. warm water, 15 crimps per 25 mm are applied,
Heat set in hot air at 130 ℃, then cut length 51
It was cut into mm to obtain short fibers having a single yarn fineness of 2 denier.

The obtained staple fibers were put into a roller card (60
m / min) to make a web with a basis weight of 20 g / m ² .
Then, a process of spraying a columnar water stream at a pressure of 120 kg / cm ² from a group of spray nozzles in which holes having a diameter of 0.1 mm are arranged in a row at a pitch of 0.6 mm is repeated three times to entangle, and then 160
It was dried with hot air at 20 ° C. for 20 minutes. When the obtained sheet was observed with a microscope, about 95% of the fibers were separated and separated.

Further, the above web was immersed in water to impregnate it with water, then needle punching was performed for entanglement, followed by heating and drying at 160 ° C. for 20 minutes. About 95% of the fibers in the obtained sheet were separated and separated, and all had a good feeling. The results are shown in Table 1.

[0031]

Examples 2 to 8 and Comparative Examples 1 to 4 Example 1 was repeated except that the melt viscosity of the polyester used as the components A and B and the polyalkylene glycol compounded in the component A were changed as shown in Table 1. I went the same way. The results are summarized in Table 1.

[0032]

[Table 1]

[Brief description of drawings]

1A to 1E are cross-sectional shapes showing an example of a splittable conjugate fiber used in the present invention.

[Explanation of Codes] 1 component of splittable conjugate fiber 2 other component of splittable conjugate fiber 3 hollow part

Claims (3)

[Claims] 1. A polyester 10 having a melt viscosity of 3500 to 12000 poises under zero shear stress at 280 ° C.
A composition prepared by mixing 10 parts by weight to 10 parts by weight of polyoxyalkylene glycol which is substantially non-reactive with the polyester is used as one component A, and the melt viscosity at 280 ° C. under zero shear stress is 300. A splittable conjugate fiber comprising a polyester of 2,500 poise as the other component B, wherein at least one of the components A and B is divided into multiple layers by the other component. 2. The splittable conjugate fiber according to claim 1, wherein the polyester constituting the components A and B is a polyester having an ethylene terephthalate unit as a main repeating unit. 3. A polyester 10 having a melt viscosity of 3500 to 12000 poise under zero shear stress at 280 ° C.
A composition prepared by mixing 10 parts by weight to 10 parts by weight of polyoxyalkylene glycol which is substantially non-reactive with the polyester is used as one component A, and the melt viscosity at 280 ° C. under zero shear stress is 300. A mechanical impact in the presence of water is applied to a splittable conjugate fiber in which at least one component of A and B is divided into multiple layers by the other component, which is a composite fiber containing the other component B of polyester of 2,500 poises. A method for producing an ultrafine polyester fiber, which comprises imparting and splitting into a fiber comprising a component A and a fiber comprising a component B.