JP2885247B2 - Durable polyester fiber with excellent water absorption - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a polyester fiber having excellent water absorbency, and more particularly to a polyester fiber having excellent durability. It is about.

(Prior art) Hydrophobic synthetic fibers, such as polyester and polypropylene fibers, are literally hydrophobic and have a remarkably poor water absorption compared to cotton and regenerated fibers. There was. Therefore, for example, how to improve water absorption while having a good permanent set property, which is a characteristic of synthetic fibers, has been taken up as an important research theme,
Unfortunately, it has not yet reached a water absorption comparable to that of natural fibers, or if it does, it is generally too expensive to be used in large quantities due to the need to go through a sophisticated modification process Only those that have such difficulties can be made.

In recent years, the role of polyester fiber, which represents polyethylene terephthalate, has become increasingly important in the field of textiles, especially in the field of non-woven fabrics. Nonwoven fabrics have been widely used in the field of non-sanitary materials such as non-sanitary materials, and in the medical field such as base cloths and fixing sheets for sheep medicine, hospital surgical gowns and masks. Among these many non-woven products, especially for baby diapers, sanitary products, and the like, a more durable hydrophilic property than conventional ones has been required. However, most of the conventional ones are based on a post-processing method of surface treatment with an oil agent, etc.
When used to some extent, the surface oil agent came off and the performance was extremely deteriorated in many cases.

Above all, in the case of wet non-woven fabric applications for diaper surface materials and sanitary pat surface materials, the papermaking process must be performed in water during the manufacturing process. The agent is dropped off, and only those which do not have sufficient performance are obtained in the final product.

(Means for Solving the Problems) The fiber of the present invention is characterized in that a predetermined amount of a high molecular weight polyoxyalkylene glycol and a metal sulfonate derivative are contained and dispersed in a polyester having a specific fiber cross-sectional shape. It is a polyester fiber having durability and water absorbency.

To describe the present invention more specifically, used in the present invention,
It is necessary that the polyoxyalkylene glycol has substantially no reactivity with the polyester described below. Here, having substantially no reactivity means not copolymerizing with the polyester. When the polyoxyalkylene glycol reacts with the polyester, the spinnability becomes poor, which is not preferable. In particular, the degree of polymerization of the polyester is reduced, and the melt viscosity during spinning becomes extremely low, and the spinnability becomes unstable, causing cross-sectional abnormalities.As a result, single yarn breakage and yarn breakage frequently occur, and continuous operation is performed. It becomes impossible.

Therefore, the molecular weight of the polyoxyalkylene glycol is preferably 1000 or more, more preferably 3000 or more. If the molecular weight is too low, the reactivity with the polyester increases, and the above-mentioned problems occur, which is not preferable. The composition may be a polyoxyethylene glycol homopolymer,
A polymer obtained by copolymerizing oxyethylene units and oxypropylene units in a random or block manner may be used. However, depending on the composition ratio between the oxyethylene unit and the oxypropylene unit, the hydrophilicity with respect to water may decrease, so that the oxyethylene unit is the main component within a range not to impair the object of the present invention. Is more preferred. Further, as the polyoxyalkylene glycol, a mixture of polyoxyethylene glycol and polyoxyethylene-polyoxypropylene copolymer may be used.

Even if the terminal of the polyoxyalkylene glycol is a hydroxyl group, even if it is blocked with a non-ester-forming organic group,
Alternatively, it may be bonded to another ester-forming organic group by an ether bond, an ester bond, a carbonate bond or the like. When the terminal is blocked with a non-ester-forming organic group, the average molecular weight of the polyoxyalkylene glycol may be as low as about 800 to 3,000.

The content of the polyoxyalkylene glycol in the polyester polymer is preferably in the range of 2.0% by weight to 10% by weight. If it is less than 2.0% by weight, the desired water absorption is insufficient. If it exceeds 10% by weight, the spinnability becomes poor, which is not preferable. Further, an antioxidant may be contained in the polyoxyalkylene glycol. In particular, when a polymer having a high melting point such as polyethylene terephthalate is used, since the spinning temperature is high, polyoxyalkylene glycol is easily oxidatively decomposed and thermally decomposed. It is effective to add and fiberize.

On the other hand, the derivative of the metal sulfonic acid salt used in combination with the above polyoxyalkylene glycol has a surfactant having at least one hydrophilic group and an appropriate hydrophobic group such as an alkyl group of the metal sulfonic acid salt in one molecule. Compounds are preferred. For example, one having the following structure is exemplified, but is not limited to this.

Here, M represents an alkali metal, usually sodium,
Potassium and lithium, with sodium being particularly preferred. R is preferably an alkyl group having 8 or more carbon atoms. In the case of an alkyl group having 7 or less carbon atoms, the compatibility with the polyester is slightly deteriorated. Further, a mixture of the above compounds may be used.

The content of the metal sulfonic acid salt derivative in the polyester component is preferably from 0.1% by weight to 5.0% by weight. If it is less than 0.1% by weight, the desired water absorption is insufficient. On the other hand, if it exceeds 5.0% by weight, the spinnability at the time of spinning becomes poor, single yarn breakage and breakage increase, which is not desirable, and the drawability is also poor. Not preferred.

The ratio of the polyoxyalkylene glycol to the sulfonic acid metal salt derivative is higher for the polyoxyalkylene glycol than for the sulfonic acid metal salt derivative. Is preferable because it has a good compatibility and forms a stable dispersion state of a micro-sea-island state, and can perform stable spinning. Preferably, the ratio between the polyoxyalkylene glycol and the sulfonic acid metal salt derivative is in the range of 6: 4 to 7: 3, from the viewpoint of the intended water absorption performance. When the content ratio of the sulfonic acid metal salt derivative was increased, it was found that the dispersion state in the polyester became uneven and the processability such as spinnability and stretchability was poor.

In the present invention, another important requirement is that the fiber must have a specific fiber cross-sectional shape. That is, as the shape of the concave portion, the shortest distance connecting the both end portions of the inlet is d, and the distance to the deepest portion of the concave portion is l, where d / l ≦ 2 is satisfied. Regular T-shaped or star-shaped modified cross-section fibers are excluded. The desired performance can be achieved when the number of concave portions is about 1 to 5. Of these, one is the simplest. The effect of the presence of the concave portion is presumed to be a great water absorbing effect due to the synergistic effect of the hygroscopicity of the kneading agent kneaded in the fiber and a kind of capillary action that quickly sucks moisture into the concave portion. . Therefore, it is preferable to make the concave shape such that d / l is a small number. d /
A good range for l is from 0.4 to 1.5, more preferably 0.6 to 1.2.

The fibers of the present invention are described, for example, in JP-A-51-109320 and JP-A-52-14.
Nos. 8221 and 52-148218. The cross section obtained by these methods has a U-shape, and any desired form of crimp, such as a coiled crimp or a mechanical crimp, can be applied as necessary. Of course, any material obtained outside the above method may be used as long as it has substantially one or more concave portions. Although U-shaped cotton has a tendency to be slightly deformed by a lateral force, the fiber is twisted when coiled crimp is applied, so the U-shaped opening is slightly closed. The shape will be more suitable for the purpose.

The polyester referred to in the present invention refers to an aromatic polyester composed of terephthalic acid and an aliphatic diol having 2 to 6 carbon atoms. In addition, a polyester obtained by copolymerizing 20 mol% or less of a third component may be used. As a copolymerization component, isophthalic acid, naphthalene dicarboxylic acid, aromatic dicarboxylic acid such as sulfoisophthalic acid metal salt, p-oxybenzoic acid,
oxycarboxylic acids such as p-β-oxyethoxybenzoic acid, adipic acid, aliphatic dicarboxylic acids such as sebacic acid, alicyclic diols such as cyclohexane dimethanolic acid, 1,3 propanediol, 1,4-butanediol, 1,6
-There are conventionally known compounds such as aliphatic diols such as hexanediol and neopentyl glycol, pentaerythritol, polyethylene glycol, polybutylene glycol, and methoxy polyethylene glycol. The fiber of the present invention can contain a conventionally known matting agent, additive, catalyst, colorant, modifier and the like. As the fiber of the present invention, a fiber having a denier of about 1 to 50 is generally suitable, but is not necessarily limited thereto. Denier is selected according to the application. For example, the fibers of the present invention are preferably used in fields where water absorption is required. Specific applications include hanging and bedding, non-woven fabrics, napkins, mops and quilts, towels and towels, foot wipes, and felt-tip pens. It is also suitable for wet type nonwoven fabric applications.

The excellent water absorption referred to in the present invention means that when the fiber is made into a cotton or non-woven fabric, the spread of a wet portion when a water droplet is dropped on the surface in the opened state is large, and the cotton-like material is immersed in water. After immersion, a centrifugal separator is used to remove excess water, so that the amount of remaining water is large. If necessary, a thin glass tube filled with cotton and placed vertically on a dish filled with water can be used to determine the suction rate of water. By judging these developments, it was confirmed that the fiber of the present invention exhibited a large water absorption superior to the conventional polyester synthetic fiber.

More specifically, it was possible to evaluate by measuring the water diffusion area and the water retention. The water diffusion area as opening and density of about 0.02 g / cm ² cotton wool, 0.37 ± this example the water was colored with red ink or the like thereon
0.02 ml is dropped and defined as the spread area of the aqueous solution after 10 minutes. The water retention is a value obtained by immersing 5 g of the opened cotton in water for 5 minutes, centrifuging at 1500 G × 10 minutes in a centrifuge, and then measuring the water content after the treatment and expressing it as a percentage of the fiber weight.

A major feature of the fiber of the present invention is that it has excellent durability such that excellent water absorption performance does not decrease at all even after washing treatment. It is possible to impart initial water absorbency by coating the concave portions on the fiber surface described in the present invention with various processing agents, treatment agents, finishing agents, and the like. For example, a polyvinyl alcohol-based treating agent, a hydrophilic antifouling agent such as Permallow T (manufactured by ICI), a nonionic,
There are various anionic and cationic hydrophilic oil agents or a combination processing agent thereof. All of these have initial performance, but it was confirmed that the performance of the fiber of the present invention hardly deteriorated while the performance was extremely reduced when washing treatment was performed. Regarding the washing durability, the measurement sample was repeatedly washed 10 times according to the JIS L0217-103 method, and the water diffusion area and the water retention after 10 times were measured to evaluate the water absorption performance.

The water diffusion area measured by the above method is about 10 to 18 mm ^{2 for} ordinary hydrophobic synthetic fibers. For example, a normal oil (having a proof power, having a sufficiently processability of such cards step) single yarn denier 6 made of polyethylene terephthalate for hanging futon granted, in the case of a hollow cross-section of 12 mm ² is The value was shown. The size of natural cotton (for cotton wool-attached cotton futon) was 10 mm ² or more. On the other hand, the fiber of the present invention had a water diffusion area of at least 40 mm ² or more, and its performance did not decrease at all even if it was subjected to washing treatment 10 times. When the fiber having the same cross-sectional shape as that of the fiber of the present invention is surface-treated with a hygroscopic processing agent, the initial performance may be 40 mm ² or more, but is considerably lowered after the ten-time washing.

When the amount of hydrated water is compared, in the case of ordinary hydrophobic synthetic fibers, it is at most about 8%, and it is only adhered and held on the surface of fibers or between fibers. However, the fibers of the present invention show a value of at least 14% or more, and
The performance did not decrease at all even after repeated washing. The most preferred form of fiber had a value of 17%, comparable to cotton (for cotton brazing futon).

Fibers exhibiting such water-absorbing properties are inadequate merely by providing a concave portion on the fiber surface, and the hydrophilic agent described above is kneaded into the polymer, which is surprisingly durable, such as the present invention, which is durable and washable. Thus, a fiber having good water absorption properties was obtained.

As described above, the fiber of the present invention containing a high molecular weight polyoxyalkylene glycol and a metal sulfonate derivative and having a fiber cross-sectional shape having at least one concave portion is excellent while being originally a hydrophobic polymer. It has a durable water absorbency, a fact that was not previously known. The reason for having such excellent water absorption is that the recess present in the cross section sucks in moisture just like a capillary, and at that time, the high molecular weight polyoxyalkylene glycol and the sulfonic acid metal salt derivative contained inside the fiber are contained. It is considered that the hydrophilizing agent promotes the wettability of the fiber surface. Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.

<Examples 1 and 2> 30 ° C. in a mixture of equal amounts of phenol and tetrachloroethane
The polyethylene terephthalate having an intrinsic viscosity [η] of 0.62 dl / g measured in step was melted, and into the molten polymer, a degree of polymerization of 11
2,000 polyethylene glycol and sodium dodecylbenzenesulfonate in a 2/1 mixture, and a predetermined amount of a hindered phenol-based antioxidant was added thereto, and then uniformly mixed with a static mixer.
Extruded from the nozzle shown in FIG.
5 to 20 cm immediately below the nozzle was wound at a cooling air velocity of 1.3 m / sec. The obtained raw yarn is stretched 190% in a water bath at 75 ° C., and then subjected to mechanical crimping of 6 to 8 pieces per inch. And then heat-relaxed at 150 ° C for 10 minutes to develop a coiled crimp, then 58mm
And cut into single-denier 6 cotton for futon. Thereafter, a web was formed to a density of 0.02 g / cm ² , 0.35 ml of a red ink aqueous solution was dropped in a standard state (20 ° C., 65% RH), and the spread area of the solution was measured 10 minutes later. The amount of hydrated water was measured using 5 g of cotton. The results are shown in Table 1. As a result, a durable fiber having good water absorption was obtained.

Note) Washing is performed according to the JIS L0217-103 method. Liquid temperature 40
2 g of a synthetic detergent for clothing is added to and dissolved in 1 ° C. water 1,
Make it a washing liquid. A sample and a load cloth are added to the washing liquid so that the bath ratio becomes 1:30, and the operation is started. After treating for 5 minutes, the operation was stopped, the sample and the load cloth were dehydrated with a dehydrator, and then the washing liquid was replaced with fresh water at room temperature, rinsed for 2 minutes at the same bath ratio, and then dehydrated. Rinse for a minute and air dry. Perform the above operations 10
The measurement sample was taken 10 times after repetition.

<Examples 3 and 4> In Example 3, as a kneading agent, 2% by weight of a polyalkylene ether, which is a random copolymer of 75 to 25% by weight of ethylene oxide and propylene oxide having an average molecular weight of 15,000, and 2% by weight of dodecylbenzenesulfonic acid Sodium was added in an amount of 1% by weight and a hindered phenol-based antioxidant was added in an amount of 0.1% by weight. In Example 4, polyethylene glycol having a degree of polymerization of 11,000 and alkyl sulfonic acid having ₁₂ to ₁₅ carbon atoms were used as kneading agents. A small amount of a hindered phenolic antioxidant is added to a 2/1 mixture of soda, so that the mixture becomes 3% by weight in the polyester, that is, 2% by weight of polyethylene glycol and 1% by weight of sodium alkylsulfonate. Other than that, it carried out by the method similar to Example 1. The results are shown in Table 1. In each case, excellent durable water absorption performance was obtained.

<Examples 5 and 6> The nozzles of FIGS. 1 (2) and 1 (3) were used, respectively, and the other conditions were the same as in Example 1. First result
It is shown in the table.

<Comparative Examples 1 to 3> Cotton was obtained under the same conditions as in Example 1 using a nozzle for obtaining fibers having an irregular cross section as shown in Table 1. First result
As shown in the table, in each case, only a low level of water absorption performance was obtained.

<Comparative Examples 4 and 5> In Comparative Example 4, polyethylene glycol having a polymerization degree of 11,000 and sodium dodecylbenzenesulfonate were mixed in a ratio of 2/1,
A mixture of a small amount of a hindered phenolic antioxidant and 0.15% by weight of a mixture in the polyester,
That is, polyethylene glycol was added in an amount of 0.1% by weight and sodium dodecylbenzenesulfonate in an amount of 0.05% by weight, and the other conditions were the same as in Example 1. The water absorption level was lower than that of Example 1.

In Comparative Example 5, polyethylene glycol having a polymerization degree of 11,000 and sodium dodecylbenzenesulfonate were mixed in a ratio of 2/1,
A mixture containing a small amount of a hindered phenol-based antioxidant was added to the polyester so that the mixture contained 22.5% by weight, that is, 15% by weight of polyethylene glycol and 7.5% by weight of sodium dodecylbenzenesulfonate. 1 was performed under the same conditions. However, stable spinning cannot be performed due to a drastic decrease in viscosity during spinning.

<Comparative Example 6> Using [η] 0.62 polyethylene terephthalate, fiberization was performed using the same nozzle as in Example 1. About 1.5 wt% of a polyvinyl alcohol-based moisture absorbent to the obtained cotton
%, Water absorption performance was measured. Although good water absorption was obtained in the initial performance, the performance deteriorated after the washing treatment.

<Examples 7, 8 and Comparative Examples 7, 8> 30 ° C in a mixture of equal amounts of phenol and tetrachloroethane
Using a polybutylene terephthalate having an intrinsic viscosity [η] of 0.85 dl / l as measured by melt spinning under the conditions shown in Table 1,
The resultant was subjected to water bath stretching and crimping treatment to obtain a single denier 5 cotton, and the cotton was similarly measured for water absorption properties. The results are shown in Table 1.

<Examples 9 and 10> 30 ° C in a mixture of equal amounts of phenol and tetrachloroethane
Using polyhexamethylene terephthalate having an intrinsic viscosity [η] of 1.05 dl / l measured in step 1, melt-spun at 200 ° C under the conditions shown in Table 1, and then subjected to water bath stretching and crimping to obtain a single yarn denier 5 cotton. And the water absorption characteristics of this cotton were measured in the same manner. Table 1 shows the results.

(Effects of the Invention) As described above, the present invention is to provide a durable polyester fiber having good water absorption performance by incorporating a specific hydrophilizing agent into a polyester having a specific cross-sectional shape.

[Brief description of the drawings]

FIGS. 1 (1), (2) and (3) are examples of nozzle holes for obtaining the fiber of the present invention, and FIG.
FIG. 3 is a model diagram for explaining a depth and a depth l.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-231221 (JP, A) JP-A-62-28405 (JP, A) JP-A-56-140115 (JP, A)

Claims (1)

(57) [Claims] (1) 2.0 to 10.0% by weight of a high molecular weight polyoxyalkylene glycol; and 0.1 to 5.0% by weight of a metal sulfonic acid salt derivative.
0% by weight, and the mixing ratio of the polyoxyalkylene glycol and the metal sulfonic acid derivative (former / latter) is 6/4.
~ 7/3, and the polyoxyalkylene glycol and the metal sulfonate derivative are uniformly dispersed throughout the cross section of the fiber in a micro-island state, and the fiber cross-sectional shape is at least It has one recess,
The concave portion satisfies the following formula: a durable polyester fiber having excellent water absorbency. d / l ≦ 2 d: Shortest distance connecting both ends of the recess l: Distance to the deepest portion of the recess