JP2000017575A - Modified polyester-based fiber-structured material and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a modified polyester-based fiber-structured material, suppressing the reduction of its strength with time, and capable of fitting to the practical use, and to provide a method for producing the same. SOLUTION: This modified polyester-based fiber-structured material is obtained by graft polymerizing a hydrophilic vinyl monomer with a fiber- structured material consisting of at least 80 wt.% polypropyleneterephthalate. The method for producing such modified polyester-based fiber-structured material, is to impart an aqueous solution containing the hydrophilic vinyl monomer and a polymerization initiator to the fiber-structured material containing at least 80 wt.% polypropylene terephthalate and heat-treat them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified polyester fiber structure which has a small decrease in physical properties of the polyester fiber structure and has a sufficient hygroscopic property and a method for producing the same.

[0002]

2. Description of the Related Art A method for modifying a synthetic fiber by graft polymerization of a hydrophilic vinyl monomer is disclosed in JP-B-59-5126.
And JP-A-51-87592. Among such methods, the method most frequently studied is to use a monomer having a carboxyl group as a hydrophilic monomer and to replace the carboxylic acid hydrogen ion after grafting to form a metal salt. In such a method, the strength is largely reduced due to hydrolysis of the polyester, and the method has not been put to practical use.

In order to improve this point, Japanese Patent Application Laid-Open No. Sho 64-40675 discloses a method in which a polyester fiber comprising a plurality of polymers is used and one polymer is selectively subjected to graft polymerization to prevent a decrease in strength. JP, JP-A-1-
No. 92477 and JP-A-9-143875. The effect of preventing the decrease in strength by such a method is remarkable, but not always sufficient, and there is a problem that the strength is reduced with time due to long-term use.

[0004]

DISCLOSURE OF THE INVENTION In view of the background of the prior art, the present invention suppresses the time-dependent decrease in the strength of a modified polyester fiber structure, and is capable of withstanding practical use. And a method for producing the same.

[0005]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the modified polyester fiber structure of the present invention is characterized in that a hydrophilic vinyl monomer is graft-polymerized to a fiber structure comprising fibers containing at least 80% by weight of polypropylene terephthalate.

In the method for producing a modified polyester fiber structure, an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator is applied to a fiber structure comprising fibers containing at least 80% by weight of polypropylene terephthalate and heat-treated. It is characterized by the following.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made to solve the above-mentioned problem, that is, to suppress a temporal decrease in strength of a polyester fiber structure modified by graft polymerization of a hydrophilic vinyl monomer,
After a thorough study of modified polyester fiber structures that can withstand practical use, and graft polymerization of a hydrophilic vinyl monomer onto a polypropylene terephthalate fiber structure, it was surprisingly solved at once. Was determined.

In the present invention, the fibrous structure containing at least 80% by weight of polypropylene terephthalate (PPT) is not a polyethylene terephthalate (PET) generally used as a polyester component but a PP.
It refers to a polyester-based fiber structure using T.

The polyester fiber structure containing at least 80% by weight of PPT in the present invention includes a yarn made of a polyester fiber containing PPT as a main component,
Fabrics such as woven, knitted, and nonwoven fabrics are included. In addition, as long as the effects of the present invention are not impaired, natural fibers such as cotton and wool or other synthetic fibers, or PET or the like, are blended with the polyester fiber used in the present invention or mixed twisted, cross-woven, cross-knitted, or the like. Can also be used. In the following description, a fiber structure made of fibers containing PPT as a main component may be simply referred to as a fiber structure.

The polyester fiber referred to in the present invention preferably includes a polyester fiber comprising PPT as a basic structural unit, a fiber comprising a polyester copolymer obtained by copolymerizing PPT with some other component,
Fibers composed of a polyester mixture obtained by blending a small amount of another organic polymer compound with PPT are also included in this. Further, the polyester fiber of the present invention may contain inorganic fine particles and low molecular organic compounds as long as the effects of the present invention are not impaired.

The main reason why PPT is desirable in the present invention is that PPT is polyethylene terephthalate (PE).
Compared with T), the rate of hydrolysis is slow, so that the decrease in strength over time is small. For this reason, the difference between the moisture content at 20 ° C. and 65% RH and the moisture content at 30 ° C. and 90% RH, which was difficult to achieve with conventional fibers, is 4% or more, and is 80 ° C. After leaving for 1 week in an atmosphere of 65% RH, the operation of performing 10 repetitions of washing is defined as one cycle, and this cycle is repeated three times. It is said that the component yarn strength after a severe forced test is 2 g / dtex or more. It is now possible to achieve performance.

However, this feature also has polybutylene terephthalate (PBT). But P
At present, fiber structures containing BT as a main component are difficult to remove wrinkles generated during processing, and it is difficult to prefer a slimy texture, and furthermore, they have low color fastness. Not used except for very few uses. In contrast, PPT has less of such problems than PBT, so
The fibrous structure composed of the fiber containing by weight has the possibility of being generally and widely used like PET.

[0013] In the present invention, the term "graft polymerization" refers to a process in which an initiator acts on a polymer constituting a fibrous structure to generate a polymerization initiation point, from which a monomer is polymerized. In the present invention, it is desirable to cause graft polymerization inside the constituent yarn of the fiber structure.

The hydrophilic vinyl monomer of the present invention includes:
A compound containing at least one unsaturated group having polymerizability, wherein the polymer is more hydrophilic than the polymer constituting the fiber to be treated. Specific examples include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic acid, acrylamide, N-vinylpyrrolidone, unsaturated amides such as N-vinylacetamide, vinyl sulfonic acid, styrene sulfonic acid, Examples thereof include unsaturated sulfonic acid compounds such as acrylamido-2-methylpropanesulfonic acid, derivatives obtained by adding polyethylene glycol to the above monomers, divinyl monomers and macromonomers containing a polyethylene glycol moiety. These may be used alone or in combination of two or more.

The hydrophilic vinyl monomer used in the present invention comprises:
It is desirable to contain a carboxyl group. Specifically, acrylic acid, methacrylic acid and derivatives thereof can be preferably used.

The carboxyl group of the modified polyester fiber structure of the present invention is desirably substituted with a metal ion. The reason for this is that by substitution with a metal ion, high hygroscopicity can be obtained with a lower carboxyl group content. As such metal ions,
Na ⁺ , Ca ²⁺ , Li ⁺ , K ^{+ and the} like can be used.

As the initiator used in the present invention, a peroxide initiator such as benzoyl peroxide, an azo initiator such as azobisisobutyronitrile, and ammonium persulfate can be used. In the present invention, since it is desirable to cause graft polymerization inside the constituent yarn of the fiber structure, hydrophobic benzoyl peroxide which is easily exhausted inside the polyester fiber is preferably used.

In the present invention, various auxiliaries can be used in addition to the hydrophilic vinyl monomer and the initiator.
Examples of such auxiliaries include surfactants and organic solvents that increase the solubility and dispersibility of the hydrophobic initiator.

In the modified polyester fiber structure of the present invention, the degree of the modification can be estimated by measuring the graft ratio and the content of the functional group. The measurement of the graft ratio can be obtained from the weight difference before and after the treatment, but it is more effective to measure the content of the functional group since the degree of modification can be known even in the final product. For example, in the case of a carboxyl group, the measurement may be performed by dissolving the fibrous structure in an appropriate solvent and titrating with a solution containing sodium hydroxide.

When a compound containing a carboxyl group is used as the hydrophilic vinyl monomer in the present invention, the content of the carboxyl group in the modified polyester fiber structure is (2.0 to 40.0) × 10 ^-4 mol. / G · fiber. The reason for this is that if the content of the carboxyl group is smaller than this, the hygroscopicity becomes insufficient, and if it is larger than this, the strength after the forced test is reduced.

The moisture content in the present invention is defined by JIS L1
096 is defined in 6.9 and is represented by the following equation.

Water content (%) = (W′−W) / W × 100 W: Absolute dry weight of sample (g) W ′: Weight of sample under specific environment (g) In the present invention, as the specific environment 20 ° C, 65% RH and 30
The moisture content at 90 ° C. and 90% RH was measured, and the difference was used as a measure of the hygroscopicity of the fiber structure. In the present invention, this difference is 4%
It is desirable that this is the case. In the present invention, this difference may be referred to as ΔMR.

In the present invention, the forced test is intended to cause the modified polyester fiber structure to deteriorate in a short time in the same manner as when the modified polyester fiber structure has been used for a long time. For this purpose, a method is used in which the fiber structure is left under high-temperature and high-humidity conditions, and additional washing is performed. That is, it is left at 80 ° C. and 65% RH for one week, and then
A method in which washing is performed 0 times as one cycle and the cycle is repeated three cycles is employed.

In the present invention, the yarn strength of a fiber structure means the strength of one multifilament constituting a woven or knitted fabric. The constituent yarn strength can be measured by using a tensile tester or the like to measure the strength of the decomposed yarn after decomposing the fibrous structure product. Here, since the characteristics of the yarns constituting the fiber structure have unevenness depending on the portions, the yarn characteristics of the fiber structure differ.
It is desirable to represent the average of the measurement results of the decomposed yarns taken from more than one part. In the present invention, it is desirable that the component yarn strength be 2 g / dtex or more after the above-mentioned forced test is performed.

In the method for producing a fibrous structure according to the present invention, a method of applying an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator to the above fibrous structure and performing a heat treatment is employed.

In the present invention, as a form of applying an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator and performing heat treatment, for example, a fiber structure is immersed in a device such as a dyeing machine filled with the aqueous solution and heat treated. Alternatively, after immersing the fibrous structure in a bath containing the aqueous solution, the fiber structure is squeezed with a roll and further subjected to a dry heat treatment or a wet heat treatment. Here, as a method of wet heat heating, a method of introducing steam can be used, but it is more effective to use heating with microwaves in combination. The heat treatment temperature is preferably from 60 ° C. to 130 ° C.

In the present invention, when a hydrophilic vinyl monomer having a carboxyl group is used, a treatment for replacing the vinyl monomer with a metal salt can be added after the graft polymerization. For this treatment, it is preferable to adopt a method of immersing and stirring the fiber structure in a bath containing a metal salt for an appropriate time using a liquid dyeing machine or the like.

[0028]

The present invention will be described in more detail with reference to the following examples. In the examples, the graft ratio, 20 ° C.,
Each measurement of the difference in moisture content between 65% RH and 30 ° C., 90% RH, and the yarn strength of the yarn constituting the fiber structure was performed by the following methods.

<Graft ratio> Calculated from the following formula based on the sample weight before and after the graft polymerization treatment.

Graft ratio (%) = (GG ′) / G ′ × 100 G: Absolute dry weight of sample after graft polymerization G ′: Absolute dry weight of sample before graft polymerization <20 ° C., 65 % RH and difference in water content at 30 ° C. and 90% RH (ΔMR)>
% For 24 hours in a thermo-hygrostat adjusted to% RH. Then, it was left in a thermo-hygrostat adjusted to 30 ° C. and 90% RH for 24 hours and weighed again. Finally, it was dried in a dryer at 110 ° C. for 1 hour to determine the absolute dry weight. The difference in the water content was calculated by the following equation.

Difference in moisture percentage (%) = ((W'-W) / W-
(W ″ −W) / W) × 100 W: Absolute dry weight of sample (g) W ′: Weight of sample at 30 ° C., 90% RH (g) W ″: Sample at 20 ° C., 65% RH <Yarn Strength (Yarn Strength of Yarn Constituting Yarn of Fiber Structure) (Yarn Strength of Yarn)> The tubular knitted sample was disassembled, and five yarns were collected from different portions. The tensile elongation of each yarn was measured with a tensile tester, and the average value was determined.

Example 1 A woven fabric (woven density: warp 104 × weft 81 / inch, basis weight: 9) using fibers (75d, 36f) composed of 100% PPT
6 g / m ² ).

This raw weave was prepared by adding 0.5 g / l of soda ash and 0.2 g / g of Gran Up US-20 (a scouring agent manufactured by Sanyo Chemical).
and scouring at 80 ° C. for 20 minutes in a bath containing
Dried at 0 ° C.

Next, 10 g / l of benzoyl peroxide as a polymerization initiator, 250 g / l of methacrylic acid as a hydrophilic vinyl monomer, and 5 parts of a cationic surfactant (Katiogen AN Super: manufactured by Daiichi Kogyo Co., Ltd.)
An aqueous solution containing a concentration of 0 g / l was prepared.

The heat-set fabric was immersed in this aqueous solution, squeezed with a mangle, wound up on a roll, and sealed with a vinylidene chloride film. The pickup rate at this time was 70% by weight with respect to the fabric after heat setting.

Then, the sealed fabric was put into a microwave treatment device (Apollopet made by Ichikin) and heated at 100 ° C.
Steam was introduced and heated for 10 minutes with microwave irradiation. After the fabric after the heat treatment was washed with hot and cold water and dried, the graft ratio was determined. The graft ratio was 11.3%.

Further, the woven fabric after the grafting was treated in an aqueous solution of soda ash 10 g / l at a bath ratio of 1:30 at 60 ° C.
The immersion treatment was performed for 30 minutes. After washing and drying this fabric,
ΔMR and constituent yarn strength were measured. ΔMR was 4.2%, and the constituent yarn strength was 3.6 g / dtex.

Finally, as a compulsory test, the fabric was
One cycle is to leave for 1 week in an atmosphere of 0 ° C. and 65% RH, and then to repeat washing 10 times.
This was repeated three cycles. Thereafter, the strengths of the constituent yarns were measured in the same manner. The component yarn strength after the forced test was 2.0 g / dtex.

As described above, a woven fabric having a ΔMR of 4% or more and a constituent yarn strength of 2 g / dtex or more after the forced test was obtained by the present invention. In addition, wrinkles hardly occurred during this fabric processing, and the slimy feeling of the texture was almost the same as that of PET.

Comparative Example 1 A woven fabric (woven density: 104 × weft 81 / inch, basis weight: 9) using fibers (75d, 36f) made of 100% PET
6 g / m ² ).

This fabric was treated in the same manner as in Example 1 except that the methacrylic acid concentration was changed to 400 g / l in order to make the graft ratio the same. The strength was measured.

As a result, the graft ratio was 10.8%, ΔM
R was 4.0%, and the component yarn strength before the compulsory test was 3.8 g /
dtex, constituent yarn strength after the constituent test is 1.5 g / dt
ex.

That is, in this comparative example, the moisture absorption rate was 4%.
As described above, the component yarn strength after the forced test was 2 g / d
tex or less.

Comparative Example 2 Using a fiber (75d, 36f) composed of 100% PBT, a woven fabric (woven density: warp 104 × weft 81 / inch, basis weight: 9)
6 g / m ² ).

The woven fabric was treated in the same manner as in Example 1 except that the methacrylic acid concentration was set to 200 g / l in order to make the graft ratio the same. The strength was measured.

As a result, the graft ratio was 11.2%, ΔM
R is 4.3%, and the component yarn strength before the compulsory test is 3.4 g /
dtex, component yarn strength after forced test is 2.1 g / dt
ex.

That is, in the case of this comparative example, the ΔMR was 4% or more, and the component yarn strength after the forced test was 2 g / dte.
x was obtained, but as a practical problem,
The wrinkles generated during the processing of the woven fabric were not completely eliminated by heat setting, and the texture was very slimy.

[0048]

According to the present invention, an excellent modified polyester fiber which has excellent hygroscopicity, does not decrease in strength, and does not cause processing wrinkles, can be used in various apparel fields,
It can be provided as a material for industrial materials.

Claims (10)

[Claims] 1. A modified polyester fiber structure obtained by graft-polymerizing a hydrophilic vinyl monomer onto a fiber structure comprising fibers containing at least 80% by weight of polypropylene terephthalate. 2. The modified polyester fiber structure according to claim 1, wherein said hydrophilic vinyl monomer contains a carboxyl group. 3. The method according to claim 1, wherein the content of the carboxyl group is (2.0 to
40.0) × 10 ⁻⁴ mol / g · fiber. 4. The modified polyester fiber structure according to claim 1, wherein said carboxyl group is substituted with a metal ion. 5. The method according to claim 1, wherein the hydrophilic vinyl monomer is acrylic acid,
The modified polyester fiber structure according to any one of claims 1 to 4, which is methacrylic acid or a derivative thereof. 6. The fiber structure according to claim 1, wherein the difference between the moisture content at 20 ° C. and 65% RH and the moisture content at 30 ° C. and 90% RH is 4% or more, and the difference between 80 ° C. and 65% RH is 80%. After one week of standing in an atmosphere, the operation of repeatedly performing washing 10 times is defined as one cycle, and the cycle is repeated three times. After the forced test, the component yarn strength is 2 g / dtex or more. The modified polyester fiber structure according to any one of claims 1 to 5. 7. A modified polyester fiber structure, wherein an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator is applied to a fiber structure comprising fibers containing at least 80% by weight of polypropylene terephthalate, followed by heat treatment. Method of manufacturing a product. 8. The method according to claim 7, wherein said hydrophilic vinyl monomer contains a carboxyl group. 9. The method for producing a modified polyester fiber structure according to claim 7, wherein the carboxyl group is replaced with a metal ion after the heat treatment. 10. The method for producing a modified polyester fiber structure according to claim 7, wherein the hydrophilic vinyl monomer is acrylic acid, methacrylic acid or a derivative thereof.