JPH02234915A - Polyester fiber having excellent water absorptivity and hand - Google Patents

Abstract

PURPOSE:To obtain the subject fiber excellent in water absorption performance and hand by including a polyoxyalkylene glycol, etc., in a polyester and forming the resultant mixture into fiber of cross section with a specific flatness. CONSTITUTION:The objective fiber, obtained by adding (B) 0.2-10.0wt.% high- molecular weight polyoxyalkylene glycol having preferably >=1,000 molecular weight without any reactivity with the component (A) and (C) 0.1-5.0wt.% metal sulfonate derivative expressed by the formula (M is alkali metal; R is >=8C alkyl) to (A) a polyester prepared by polymerizing terephthalic acid and a 2-6C aliphatic diol, spinning and drawing the resultant mixture and having a flat cross section and 1.5-15 ratio (L/W) of the maximum length (L) to the maximum width (W) thereof.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a polyester fiber having excellent water absorbency, and its purpose is to provide a polyester fiber with particularly durable water absorbency and good properties. 0 (Prior art) Hydrophobic synthetic fibers, such as polyester and polypropylene fibers, are literally hydrophobic and are significantly inferior in water absorption compared to cotton or recycled fibers. There were problems in using it for applications that required water absorption. Therefore, how to improve water absorption while maintaining the characteristics of synthetic fibers, such as good permanent setting properties, has been an important research topic for some time.
Unfortunately, it has not yet reached the level of water absorption comparable to that of natural fibers, or even if it has, it is expensive to use in large quantities because it requires a sophisticated modification process. Only those with drawbacks such as being too large could be made.

In recent years, polyester fibers such as polyethylene terephthalate have been playing an important role in the textile field, especially in the non-woven fabric field.
In the field of non-hygienic materials such as drainage bags for kitchen utensils,
Non-woven fabrics have been widely used in the medical field, such as base fabrics and fixation sheets for medical supplies, surgical gowns for hospitals, and masks. Among these many nonwoven agricultural products, baby diapers, sanitary products, and other products are required to have hydrophilic properties that are more durable than conventional products. However, most of the products up to this point are processed after surface treatment with oil, etc., and although this has good initial performance, after a certain amount of use, the surface oil falls off and the performance deteriorates dramatically. There were many.

Among these, wet-type nonwoven fabric applications such as surface materials for mortuaries and sanitary bats require a paper-making process in water during the manufacturing process, so the method of coating the fiber surface with a hydrophilic and curing agent is not suitable for use during paper-making. The hydrophilic agent falls off and the final product is only one that does not maintain sufficient performance.

Furthermore, in recent years, even disposable nonwoven fabrics are often used in direct contact with human skin, and there has been a demand for fabrics that feel good when in contact with the skin, but conventional fabrics have no skin damage properties. Even if they were able to overcome this problem, there was not much consideration given to the texture.

(Means for Solving the Problems) The fiber of the present invention is characterized by containing and dispersing a predetermined amount of a high molecular weight polyoxyalkylene glycol and a sulfonic acid metal salt derivative into a polyester having a specific fiber cross-sectional shape. It is a polyester TA fiber that has durable water absorption and good texture.

To explain the present invention more specifically, the polyoxyalkylene glycol used in the present invention needs to have substantially no reactivity with the polyester described below. Here, "having substantially no reactivity" means not copolymerizing with polyester. Reaction with polyoxyalkylene glycol 75Z polyester is not preferred because spinnability becomes poor. In particular, the degree of polymerization of polyester is lowered, and the melt viscosity during spinning is extremely lowered, resulting in unstable spinnability and 1-plane abnormality, which results in single fiber breakage, frequent occurrence of broken yarns, and continuous Driving becomes impossible.

Therefore, the polyoxyalkylene glycol preferably has a molecular weight of IOOO or more, preferably 3,000 or more. If the molecular weight is too low, the reactivity with the polyester will increase and the above-mentioned problems will occur, which is not preferable. The composition may be a single polymer of polyoxyethylene glycol or a polymer obtained by copolymerizing oxyethylene units and oxypropylene units in a random or block form.

However, depending on the composition ratio of oxyethylene units and oxypropylene units, the hydrophilicity toward water may decrease, so it is better to have oxyethylene units as the main component as long as it does not impede the purpose of the present invention. preferable. Further, as the polyoxyalkylene glycol, a mixture of polyoxyethylene glycol and polyoxyethylene-polyoxypropylene copolymer may be used.

Whether the terminal of polyoxyalkylene glycol is a hydroxyl group, blocked with a non-ester-forming organic group, or bonded to another ester-forming organic group through an ether bond, ester bond, carbonate bond, etc. In the case of a polyoxyalkylene glycol whose zero end is blocked with a non-ester-forming organic group, the average molecular t of the polyoxyalkylene glycol may be as low as about 800 to 3,000.

The amount of polyoxyalkylene glycol contained in the polyester polymer is preferably in the range of 0.2 weight percent to 10 weight percent. If it is less than 0.2tt%, the desired water absorption is insufficient. If it exceeds 10 tt%, spinnability becomes poor, which is not preferable. Further, an antioxidant may be included in the polyoxyalkylene glycol. In particular, when using a polymer with a high melting point such as polyethylene terephthalate, the spinning temperature becomes high and polyoxyalkylene glycol tends to undergo oxidative decomposition and thermal decomposition. To prevent this, hindered phenol-based antioxidants are used. It is effective to add it to iRfa.

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

(1) R@S03M, +2) RC}SO3M,
(81 R-SO3M1(4)R-0αH2CHCO
OR 1 (s) R-CON-SO3M, SOsM (a) ROSO3M, (γ) R-0 (C
2H40)nS03M,is+R-{miQO(C2
}-{20)nS03M, . ,9} fcONI
{-OS03M where M represents an alkali metal, usually
These include 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 polyester becomes somewhat poor. Also, a mixture of the above compounds may be used.

The content of the sulfone related metal salt derivative in the polyester component is 0. 1.5 from the weight clerk. Preferably, it is 0 weight percent. 0. If it is less than 1% by weight, the desired water absorbency is insufficient. If the percentage exceeds 5.01%, the stringiness during spinning will be poor, single yarn breakage and yarn breakage will increase, which is undesirable. This is not desirable as it becomes a thread.

In addition, regarding the abundance ratio of polyoxyalkylene glycol and sulfonic acid metal salt derivative, it is better to have more polyoxyalkylene glycol than sulfonic acid metal salt derivative, while polyoxyalkylene glycol and sulfonic acid metal salt derivative are more abundant than polyester, polyoxyalkylene glycol, and sulfonic acid metal salt derivative. It has good compatibility with other materials and forms a stable dispersion state like a microscopic seabird, making it possible to perform stable spinning.
Preferably, the ratio of the polyoxyalkylene glycol to the sulfonic acid metal salt derivative is preferably in the range of 6:4 to 77j3 from the viewpoint of water absorption performance, which meets the objective. It has been found that when the proportion of the sulfonic acid metal salt derivative increases, the dispersion state in the polyester becomes non-uniform, resulting in poor workability such as spinnability and stretchability.

Another important requirement of the present invention is that the fibers must have a specific cross-sectional shape. That is, the present invention provides flatness Iy/W
(L and W are the length and maximum width of the fiber flower cross section, respectively) are 1. It is a virtually linear flat fiber that satisfies the conditions 5 to 15.0 The flatness of this fiber is determined by microscopically observing the lateral surface of the fiber and determining its maximum length (L). Measure the width (W) and calculate L/
The Lβ of the fiber is at least 20, which is what is required by W.
Measure the number of holes W, and use the average value as the flatness. This fiber. An example of a skin cross section is shown in Figure 1 (including hollow flat fibers).

According to the present invention, H. The flatness of 4a is 1.5 to 15, preferably 2.5 to 8.0. If it is less than 1.5, the effect of the present invention will not be exhibited, and if it exceeds 15, spinnability and stretchability will deteriorate, so it is preferable. do not have.

The main reason why the spinnability decreases when the number exceeds 15 is that the high molecular weight polyoxoalkylene glycol and the sulfonic acid metal salt derivative are kneaded into fine islands in the polymer, which makes it difficult to discharge the spinning nozzle. At times, the melt viscosity balance tends to be disrupted, and as the degree of flatness increases, oblique alignment and screw dropout tend to occur, resulting in frequent single yarn breakage.

Such cross-sectional fibers used in the present invention are discharged from, for example, a nozzle shown in FIG.
fibers are easily formed by The taken-off undrawn yarn is drawn 1.1 to 5.0 times by a conventional method.

The obtained flat cross-section fibers may be crimped in any desired form, such as coiled crimps or mechanical crimps, if necessary. Of course, materials obtained by methods other than those described above may be used as long as they have substantially the flatness of the present invention.

The reason why the fiber of the present invention has excellent water absorbency is as follows.
A model diagram of the aggregated state of single fibers is shown in Figure 3. Flat fibers tend to be in an aggregated state in which the single fibers overlap each other.
In that case, i-degree voids occur in the length and force direction between the single fibers,
The synergistic effect between the voids and the improvement in surface WJ wettability due to the hygroscopicity of the kneading agent kneaded into the fibers is immediately apparent. +Jl! It is estimated that a wonderful water-absorbing effect will be developed in which the water present on the fiber surface is sucked and transferred between the fibers. Another major feature of the fibers of the present invention is that they have a good texture. . It has been said that this is due to the fact that when an external force is applied to the flat cross-section fibers, it is easy to lie down, resulting in a soft touch.
The fiber of the present invention has high molecular weight polyoxyalgylene glycol and sulfonic acid metal salt derivative kneaded into the fiber, so a kind of plasticizer effect is expressed in the polymer, and it is easier to sleep against 6 forces. It has been discovered for the first time that the polyester fibers have a softer feel than the regular polyester flat fibers. Further, the effect of this softness is not limited to the texture, but is also suitable, for example, when a nonwoven fabric is produced by a hydroentanglement method, good entanglement property can be obtained.

The polyester referred to in the present invention refers to an aromatic polyester consisting of terephthalic acid and an aliphatic diol having 2 to 6 carbon atoms, but it may also be a product obtained by copolymerizing these with 20 mol% or less of @3 components.

Copolymerization components include aromatic dicarboxylic acids such as isophthalic acid, naphthalene dicarboxylic acid, and sulfoisophthalic acid metal salts, oxycarboxylic acids such as p-oxybenzoic acid and p-β-oxyethoxybenzoic acid, and fats such as adibic acid and sebacic acid. group dicarboxylic acids, alicyclic diols such as cyclohexanedimethanol, 1,3 propane diol,
1.4-butanediol, 1.6-hexanediol,
Conventionally known compounds include aliphatic diols such as neopentyl glycol, pentaerythritol, polyethylene glycol, polybutylene glycol, and methoxypolyethylene glycol. The fibers of the present invention can contain conventionally known matting agents, additives, catalysts, colorants, modifiers, and the like. The fiber of the present invention is usually 1 to 5
A denier of about 0 is suitable, but it is not necessarily limited to this. The denier is selected depending on the application. For example, the fibers of the present invention are preferably used in fields where water absorption is required. Specific uses include hangings and mattresses, non-woven fabrics, napkins, mops and rags, towels and towel blankets, and wiper sheets.

Furthermore, since the fibers of the present invention have a good soft feel, they are particularly suitable for nonwoven materials used in direct contact with human skin.

In the present invention, excellent water absorption means that when the fiber is made into a cotton-like or non-woven cloth, the wetted part becomes sticky when a drop of water is dropped on the open surface of the fiber. After soaking in gold water, the excess water is removed by centrifugation, and the residual water content is large. If necessary, it can also be determined by filling a thin glass tube with cotton and standing it vertically over a dish filled with water to determine the water absorption rate. By determining these existing trenches,
It has been found that the silicate material of the present invention exhibits superior water absorbency compared to conventional polyester synthetic fibers.

More specifically, it was possible to evaluate by measuring the water diffusion area and water retention rate. The water diffusion area refers to raw cotton that is opened to a density of about 0.02P/1, and water colored with red ink, etc., is poured on top of it.
．． It is defined as the spread area of the aqueous solution after 37±0.02d dropping and 10 minutes. This operation was repeated for 101 gl and the average value was taken. In addition, the repeated water absorption rate means that a nonwoven fabric sheet with a basis weight of 40r/rrl is prepared, a square sample of 5α x 5tM1 is sampled from the sheet, and the sample is dropped onto the water surface, so that water covers the entire surface of the sample by 1
The time it took for the test to stop was measured. Thereafter, the sample was drained with a counter cloth, dried in an open air at 50°C, and measured again in the same manner. This operation was repeated 10 times and evaluated based on the average directness.

Texture evaluation was carried out by sensory evaluation, with 20 people pasting samples shaped like non-woven fabrics with the same weight on their skin, and 24
A relative comparison was made with the time pasted.

The major feature of the fibers of the present invention is that they have excellent water absorbing properties and excellent durability that does not deteriorate at all even after washing. It is possible to impart initial water absorbency to the fiber surface having the same cross-sectional shape as described in the present invention by coating it with various processing agents, treatment agents, finishing agents, etc. Examples include polyvinyl alcohol-based treatment agents, hydrophilic antifouling agents such as Permalose T (manufactured by ICI), nonionic, anionic, and cationic hydrophilic oil agents, and combination agents thereof. All of these have initial performance, but when washing treatment is performed, the performance deteriorates extremely, whereas it was confirmed that the performance of the EA fiber produced according to the present invention hardly deteriorates. Regarding washing durability, the measurement sample was washed 10 times according to the JIS LO217-103 method, and the water diffusion area and repeated water absorption rate after 10 times were measured to evaluate the water absorption performance.

The water diffusion area measured by the above method is about 10 to 184 in the case of ordinary hydrophobic synthetic fibers. For example, a single yarn made of polyethylene terephthalate for duvets coated with an ordinary oil agent (having electrical resistance and sufficient passability through processes such as carding) may have a denier of 6, and a hollow cross-section yarn with a denier of 12. The value was shown. In addition, natural cotton (for cotton wax-adhered raw cotton futon cotton) had a score of 101 or higher. In contrast, the fibers of the present invention had a water diffusion area of at least 401 or more, and their performance did not deteriorate at all even after being washed 10 times. Unexploded E! To fibers with the same cross-sectional shape as AIR fibers,
Even when a hygroscopic finishing agent is allowed to escape from the surface, the initial performance may be 401 or higher, but it deteriorates considerably after washing 10 times.

In addition, when comparing the repeated water absorption speed, the fiber of the present invention shows a value of at least 10 seconds or less, whereas the rate of repeated water absorption is 60 seconds or more in the case of ordinary hydrophobic synthetic fibers, and it was measured repeatedly 10 times. Even after that, the performance did not deteriorate at all. Even when a FA male with a cross-sectional shape similar to that of the fiber of the present invention is surface-treated with a hygroscopic finishing agent, the initial performance may be less than 10 seconds, but when all repeated measurements are carried out, the surface-treating agent is It was found that the shedding progressed and the water absorption rate decreased to 10 seconds or more.

It is not enough to simply flatten the surface of the fR fiber 1 to make the fibers exhibiting such custom water absorption properties. This is why it is difficult to obtain fibers with such surprising water absorption properties and good texture.

As explained above, the specific flattened fiber containing the high molecular weight polyoxyalkylene glycol and sulfonic acid metal salt derivative according to the present invention has excellent durability even though it is originally a hydrophobic polymer. It has excellent water absorbency and a good texture, which was previously unknown.

The reason for this excellent water absorbency is that the appropriate voids created between the single fibers in the fiber aggregate absorb moisture, etc., and the high molecular weight polyoxyalkylene glycol and metal sulfonate contained inside the fibers. This is thought to be because the hydrophilic agent of the salt derivative promotes the wettability of the fiber surface. The present invention will be explained below with reference to Examples, but is not limited thereto.

Examples 1 to 4> In a mixture of equal amounts of phenol and tetrachloroethane at 30°C
The intrinsic viscosity [η] measured at is 0. 6 2 d7 polyethylene terephthalate was melted, and a small amount of hindered phenolic antioxidant was added to the melted polymer, which was mixed with polyethylene glycol todecyl benzene sulfonic acid sorta'i 2/1 with a degree of polymerization of 11,000. After adding a predetermined amount of the mixture, the mixture was uniformly mixed using a static mixer, and then extruded through the nozzle shown in FIG. 2 (c) kept at 285° C. and rolled up. The obtained yarn was heated to 75℃
Stretched 3.5 times in a water bath, then mechanically crimped, and then coated with an oil agent containing an ethylene oxide adduct of stearyl phosphate as a main component. Granted to the lwt%,
After drying at 130° C. for 10 minutes, it was then cut into a length of 51 m to produce single yarn denier 2 cotton. After that, it was made into a web with a density of 0.0 2 f/d K,
Under standard conditions (20°C, 65% RH), red ink aqueous solution was
．． Ten minutes after dropping 35 d of water, the spreading area of the solution was measured. The same measurements were taken after washing 10 times. Also,
Cotton'lr: 4 0? /rl wet cloth, then 21 dollar punch treatment to create a non-woven fabric, cut a 5 cm x 5 cm square piece from the non-woven fabric, drop it on the water surface, and the water spreads over the entire surface of the sample. The water absorption rate was measured 10 times by manipulating and dividing. The results are shown in Table 1, and fibers with durability and good water absorption performance were obtained. The texture of the nonwoven fabric was also soft and good.

Note) Washing machine <rj:, carried out in accordance with JIS LO217-103 method. Synthetic laundry detergent was added and dissolved in a ratio of 22 parts to 1 ton of water at a liquid temperature of 40°C to obtain a washing liquid. A sample and, if necessary, a load cloth are added to the washing solution at a bath ratio of 1:30, and operation is started. After processing for 5 minutes, stop the operation, dehydrate the sample and turtle cloth in a dehydrator, then change the washing solution to fresh water at room temperature, rinse for 2 minutes at the same bath ratio, dehydrate again, Rinse for 2 minutes and air dry. The above operation was repeated 10 times, and a measurement sample was obtained after 10 times.

Examples 5 to 10> Examples 5 to 10 were carried out under the same conditions as in Example 1 except that the nozzle shapes shown in Table 1 were used. The results are shown in Table 1.

<Example 11.12) In Example 11, a polyalkylene ether which is a random copolymer of 75:251 k% of ethylene oxide and propylene oxide with an average molecular weight of 15,000,
Example 12 contains 4% by weight of sodium dodecylbenzenesulfonate, Example 111dxNi%, and Example 12 contains 2! i%
, 0.1% by weight of hindered phenol-based anti-aggressive agent
The other steps were the same as in Example 1.

The results are shown in Table 1. All of them have excellent durable water absorption performance and a good texture. If you can get the white cloth h. rc.

<Examples 13 and 14> Polyethylene glycol with a polymerization degree of iooo and charcoal X a
CL2~Cts alkyl sulfonic acid soda 2/
Example 13 was prepared by adding a small amount of hindered phenolic antioxidant to the mixture of 1 and 3 into the polyester.
In Example 14, f, i.e., 4 ft of polyethylene glycol, was added so that the mixture was 63 ft. = 4% Sodium alkylsulfonate was added so as to have a concentration of 2%, and the preparation was carried out in the same manner as in Example 1. The results are shown in Table 1. In all cases, nonwoven fabrics with excellent durable water absorption performance and good texture were obtained.

<Comparative Examples 1 and 2> Cotton was obtained under the same conditions as in Example 1 using a nozzle for obtaining an irregular cross section as shown in Table 1. The results are shown in Table 1, and in all cases only a low level of water absorption performance was obtained. Furthermore, the texture of the nonwoven fabric was also inferior to that of Example 1.

<Comparative Examples 3 and 4> In Comparative Example 3, a mixture of 2/1 polyethylene glycol totodecylbenzenesulfonic acid sorta with a degree of polymerization of 11,000 and a small amount of hindered phenol antioxidant was added to polyester. So that the mixture is 0.15 parts by 1 liter, that is, polyethylene glycol o. tx
t%, 0.05 weight t of sodium dodecylbenzenesulfonate
%, 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 4, polyethylene glycol with a degree of polymerization of 11,000 and sodium dodecylbenzenesulfonate were mixed in V1, and a small amount of hindered phenol antioxidant was added to polyester so that the mixture was 22.5% by weight. That is, 15% by weight of polyethylene glycol and 7.5% by weight of sodium dodecylbenzenesulfonate were added, and the other conditions were the same as in Example 1. However, the viscosity decreased significantly during spinning, making stable spinning impossible.

Comparative Examples 5 and 6> In Comparative Example 5, nozzle t/W 2. At 0, the fiber analysis surface flatness L/Wl. 2 was carried out in the same manner as in Example 1, but both water absorption performance and texture were at a lower level than in Example 1. Comparative Example 6 has nozzle t/W 2 5.
0 Te, fiber ia cross section flatness L L/W 1 7. O o
Although the same method as in Example 1 was carried out using Moo, the discharge condition was unstable during spinning, and slanting and screw dropping occurred frequently, resulting in poor spinnability.

Comparative Example 7> [Using polyethylene terephthalate with η10.62,
Fiber formation was performed using the same nozzle as in Example 1. About 1 hour of polyvinyl alcohol-based moisture absorbing finishing agent is applied to the obtained cotton.
After applying 5 wt%, water absorption performance was measured. Although good water absorption was obtained in the initial performance, the performance decreased after the washing treatment. In addition, the nonwoven fabric after the washing treatment was slightly harder than that of Example 1, and its texture was slightly inferior.

Examples 8 and 9, Comparative Examples 9 and 10) In a mixture of phenol and tetrachloroethane at 30°C
Using polybutylene terephthalate whose intrinsic viscosity [η] measured in
The water absorption properties of this cotton were measured in the same manner.

The results are shown in Table 1.

Examples 10 and 11> In a mixture of equal amounts of phenol and tetrachloroethane at 30°C
Using polyhexamethylene terephthalate with an intrinsic viscosity [η] measured by Cotton of denier 2 was obtained, and the water absorption properties of this cotton were similarly measured. Table 1 shows the results.
Margins below (Effects of the Invention) As described above, the present invention produces polyester fibers that have durable, good water absorption performance and good texture by incorporating a specific hydrophilic agent into polyester having a specific cross-sectional shape. It is about providing.

[Brief explanation of the drawing]

Figures 1 (A), (C), (C) and (2) are examples of the cross-sectional shape of substantially linear flat fibers used in the present invention, and Figures 2 (A) and (C) are examples of the cross-sectional shapes of substantially linear flat fibers used in the present invention. , (c) show examples of nozzle shapes for obtaining the same flattened fibers. FIG. 3 is a model showing an example of the aggregate state of the flat fibers of the present invention.

Claims (2)

[Claims] (1) 0 high molecular weight polyoxyalkylene glycol
．． 2 to 10.0% by weight, and 0.0% by weight of the sulfonic acid metal salt derivative.
1 to 5.0% by weight, respectively, and the fiber cross-sectional shape is a flat cross-section with an oblateness L/W of 1.5 to 15 (where L is the maximum length of the fiber cross section and W is the maximum width). Polyester fiber with characteristics of good water absorption and texture. (2) The polyester fiber having good water absorbency and texture according to claim 1, characterized in that the water diffusion area after washing treatment is 40 mm^2 or more, and the repeated water absorption rate is 10 seconds or less. .