JP2000017576A - Modified polyester-based fiber-structured material and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester-based fiber-structured material, modified by graft polymerizing a hydrophilic vinyl monomer, 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 heat-treating either one of a fiber-structured material consisting of a polyester-based composite fiber in which a polybutyleneterephthalate or a polypropyleneterephthalate occupies >=20% and <80% fiber cross section, or a fiber-structured material consisting of a polyester mixed fiber containing >=20% and <80% fiber consisting of the polybutyleneterephthalate or polypropyleneterephthalate, then imparting an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator thereto, and heat- treating 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-based fiber structure having a small decrease in physical properties of the polyester-based fiber structure and having sufficient hygroscopicity, 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 Japanese Patent Publication No. 59-5126 and Japanese Patent Application Laid-Open No. 51-87592. Among such methods, the method most often studied is a method in which a monomer having a carboxyl group is used as a hydrophilic monomer, and a hydrogen ion of a carboxylic acid is replaced after grafting to form a metal salt. In the method, the strength is greatly 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-A-1-92
No. 477, and Japanese Patent Application Laid-Open No. 9-143875. The effect of preventing the reduction in strength by such a method is remarkable, but not always sufficient, and there has been a problem that the strength decreases 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 strength of a polyester-based fiber structure modified by graft polymerization of a hydrophilic vinyl monomer, and It is an object of the present invention to provide a modified polyester-based fiber structure capable of withstanding high temperature 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 a fiber structure comprising a polyester conjugate fiber in which polybutylene terephthalate or polypropylene terephthalate accounts for 20% or more and less than 80% of the fiber cross-sectional area. However, 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 after leaving for 1 week in an atmosphere of 80 ° C. and 65% RH, The operation is repeated ten times as one cycle, and the composing yarn strength after the forced test in which the cycle is repeated three times is 2 g / dtex or more, and it is characterized by polybutylene terephthalate or polypropylene terephthalate. Fiber structure comprising a polyester-based mixed yarn containing 20% or more and less than 80% by weight of It, the fiber structure is, 20
The difference between the moisture content at 65 ° C. and 65% RH and the moisture content at 30 ° C. and 90% RH is 4% or more, and at 80 ° C. and 65% RH
After one week of standing in an atmosphere of the above, the operation of performing 10 repetitions of washing is defined as one cycle, and this cycle is repeated three cycles. The component yarn strength after the forced test is 2 g / dtex or more. .

Further, according to the method for producing a modified polyester fiber structure of the present invention, the polybutylene terephthalate or the polypropylene terephthalate has a fiber cross-sectional area of 2%.
A fibrous structure composed of a polyester-based composite fiber having a content of 0% or more and less than 80%, or a polyester-based mixed fiber containing a fiber composed of polybutylene terephthalate or polypropylene terephthalate in a proportion of 20% to less than 80% by weight. One of the fibrous structures is heat-treated, and thereafter, an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator is applied and heat-treated.

[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,
A polyester polyester fiber structure capable of withstanding practical use has been studied diligently, and a polyester-based composite fiber containing a polybutylene terephthalate component or a polypropylene terephthalate component in a specific ratio, or a polyester-based mixed fiber yarn, Then, when the graft polymerization of a hydrophilic vinyl monomer was performed, it was surprisingly found that such a problem could be solved at once.

As the polyester fiber structure in the present invention, yarns, woven fabrics, knitted fabrics, non-woven fabrics and other fabrics made of polyester fibers can be used. In addition, as long as the effects of the present invention are not impaired, natural fibers such as cotton and wool and other synthetic fibers are used in combination with the polyester fibers used in the present invention in the form of blended or twisted, interwoven, interwoven or the like. be able to. In the following description, this polyester fiber structure may be simply referred to as a fiber structure.

The polyester fiber of the present invention preferably includes a polyester fiber comprising polyethylene terephthalate as a basic structural unit, a fiber comprising a polyester copolymer obtained by copolymerizing polyethylene terephthalate with some other component, Fibers composed of a polyester mixture obtained by blending a small amount of another organic polymer compound with polyethylene terephthalate 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 moisture content in the present invention is defined by JISL10
It is specified in Section 6.9 of 96 and can be obtained 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) Modified polyester system of the present invention The fiber structure is 20 ° C, 6
The difference in moisture content when the moisture content is measured in a specific environment of 5% RH, 30 ° C. and 90% RH is expressed as a measure of the hygroscopicity of the fibrous structure. In the present invention, this difference in moisture content is
Desirably, it is 4% or more. In the present invention, this difference may be referred to as ΔMR.

The above-mentioned forced test in the present invention is intended to cause deterioration of the modified polyester fiber structure in a short time in the same manner as in the case where the modified polyester fiber structure has been used for a long time. For this purpose, a method of leaving the fiber structure under high temperature and high humidity conditions and additionally performing washing repeatedly is used. That is, it is left at 80 ° C. and 65% RH for 1 week, and then
The method of repeating washing three times is adopted as one cycle, and the method is repeated three cycles.

The constituent yarn strength of the modified polyester fiber structure of the present invention refers to the strength of one multifilament constituting a woven fabric, a knitted fabric, or the like. The strength of the decomposed yarn after the above can be measured using a tensile tester or the like. Here, since the characteristics of the yarns constituting the fiber structure vary depending on the portions, it is preferable to average the measurement results of the decomposed yarns taken from five or more different portions of the fiber structure.
In the present invention, the component yarn strength is desirably 2 g / dtex or more even after the forced test.

In the present invention, the term "graft polymerization" refers to a process in which an initiator acts on a polymer constituting the 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 is
It is desirable to contain a carboxyl group. Specifically, acrylic acid, methacrylic acid and derivatives thereof can be used. In addition, the carboxyl group of the modified polyester fiber structure of the present invention is desirably substituted with a metal ion. Those substituted with such metal ions,
Higher hygroscopicity can be achieved with lower carboxyl group content. Such metal ions include, for example, N
a ⁺ , Ca ²⁺ , Li ⁺ , K ^{+ and the} like can be preferably employed.

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, it is preferable to use hydrophobic benzoyl peroxide or the like which is easily exhausted inside the polyester fiber.

In the present invention, various auxiliaries can be used in addition to the hydrophilic vinyl monomer and the initiator.
Examples of such an auxiliary include a surfactant and an organic solvent that enhance the solubility and dispersibility of a 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 is performed by dissolving the fibrous structure in an appropriate solvent,
The titration may be performed with a solution containing sodium hydroxide. In the present invention, when a compound containing a carboxyl group is used as the hydrophilic vinyl monomer, the content of the carboxyl group in the modified polyester fiber structure is (2.0 to 40.
0) × 10 ⁻⁴ mol / g · fiber is desirable. The reason 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.

In the present invention, a polyester-based composite fiber in which polybutylene terephthalate (PBT) or polypropylene terephthalate (PPT) accounts for 20% to less than 80%, preferably 20 to 45% of the fiber cross-sectional area,
Alternatively, a fiber structure using a polyester-based mixed yarn containing a fiber made of polybutylene terephthalate or polypropylene terephthalate at a ratio of 20% to less than 80% by weight, preferably 20 to 45% by weight is used. This is because PBT or PPT has a low glass transition point and polyethylene terephthalate (PET)
This is because the graft polymerization of the hydrophilic vinyl monomer is easier than that of the hydrophilic vinyl monomer. Another reason is that PBT or PPT has a lower hydrolysis rate than PET, and thus is hardly deteriorated even when the graft ratio is increased. This P
When graft polymerization is performed on a composite fiber or a mixed fiber using BT or PPT, the graft reaction is concentrated on PBT or PPT, which is more easily graft-polymerized than PET and has less strength reduction, and a reduction in the overall strength can be suppressed. PBT
The reason why it is desirable that the PPT is contained in the above-mentioned ratio is that, in the case of a composite fiber having a fiber cross-sectional area of less than 20% or a mixed fiber having a content of less than 20% by weight, polymerization into PET proceeds too much. This is because a decrease in strength cannot be suppressed, and if it is larger than this, problems such as a decrease in rigidity and wrinkles, which are weak points of PBT or PPT, are likely to occur. In addition, the composite fiber of 20 to 45% of the fiber cross-sectional area or the content of
４５45% by weight of the mixed fiber, especially in clothing fabrics,
It is possible to remarkably suppress the weaknesses of PBT or PPT, such as the reduction in rigidity and the generation of wrinkles, and also to achieve the effect of maximizing these advantages.

In the method for producing a fibrous structure according to the present invention, the fibrous structure composed of a composite fiber or a mixed fiber using PBT or PPT is heat-treated, and then contains a hydrophilic vinyl monomer and a polymerization initiator. An aqueous solution is applied and heat treatment is performed again.

In the present invention, the heat treatment before the graft polymerization is performed as it is when the fiber structure is produced,
This is performed after removing the oil agent and the sizing agent by desizing. By performing this heat treatment, PET becomes less susceptible to graft polymerization than crystallization, whereas PBT or PBT
In the case of PT, crystallization does not proceed easily, and the graft polymerizability does not change much as compared with the case without heat treatment. As a result, the degree of concentration of the graft reaction on PBT or PPT is higher than in the case where no heat treatment is performed, and it is possible to create a state where almost no graft polymerization is performed on PET. For this reason, at least the strength of PET hardly decreases even after the forced test, and the strength sufficient for practical use can be maintained.

The temperature of the heat treatment before the graft polymerization is 150
It is desirable that the temperature is not less than 200C and not more than 200C. As a device used for the heat treatment, a dry heat treatment device used for ordinary fiber processing such as a tenter or a resin processing machine may be used.

In the present invention, an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator may be applied and heat-treated again, for example, by immersing the fiber structure in an apparatus such as a dyeing machine filled with the aqueous solution and heat-treating the fiber structure. Or immersing the fibrous structure in a bath containing the aqueous solution, squeezing with a roll, and further performing 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 in combination with microwaves. Heat treatment temperature is 60
It is desirable that the temperature is not less than 130 ° C. and not more than 130 ° C.

In the case of using a carboxyl group-containing hydrophilic vinyl monomer in the present invention, a treatment of substituting a metal salt after the graft polymerization can be added. For this treatment, a method of immersing and stirring the fiber structure in a bath containing a metal salt for an appropriate time using a jet dyeing machine or the like is preferably adopted.

[0026]

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

Graft ratio, 20 ° C., 65% RH and 30
Each measurement of the difference in the water content at 90 ° C. and 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: 104 ×) using polyester-based composite fibers (75d, 36f) in which the sheath portion is made of PBT and the core portion is made of PET and the PBT makes up 50% of the fiber cross-sectional area.
81 lines / inch, weight: 96 g / m ² ).

The raw weave was prepared by adding 0.5 g / l of soda ash and 0.2 g / granup 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. Then, use a pin tenter for 18
Heat set at 0 ° C. for 1 minute.

Next, 10 g / l of benzoyl peroxide was used as a polymerization initiator, 250 g / l of methacrylic acid was used as a hydrophilic vinyl monomer, and 5 cationic surfactants (Katiogen AN Super: Daiichi Kogyo Co., Ltd.) were added.
An aqueous solution containing a concentration of 0 g / l was prepared. The woven fabric after heat setting 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% with respect to the fabric after heat setting.

Then, the sealed fabric was put into a microwave processing apparatus (Apollopet manufactured by Ichikin), and heated at 100 ° C. for 10 minutes while irradiating with microwaves. After the fabric after the heat treatment was washed with hot and cold water and dried, the graft ratio was determined.

Further, the woven fabric after the grafting was treated in an aqueous solution of 10 g / l of soda ash at a bath ratio of 1:30 at 60 ° C.
The immersion treatment was performed for 0 minutes. After washing and drying the woven fabric, Δ
The MR and constituent yarn strength were measured.

Finally, as a compulsory test, the woven fabric was
This was left to stand at 65 ° C. and 65% RH for 1 week, and thereafter, the washing was repeated 10 times. Thereafter, the strengths of the constituent yarns were measured in the same manner.

The results are shown in Table 1, from which ΔMR was 4
% Or more, the component yarn strength after the forced test is 2 g / dtex
The above woven fabric was obtained.

Example 2 A woven fabric (woven density: 104 × warp) made of a polyester-based composite fiber (75d, 36f) in which the sheath portion is made of PPT and the core portion is made of PET, and PPT makes up 50% of the fiber cross-sectional area.
81 lines / inch, weight: 96 g / m ² ).

The woven fabric was treated in the same manner as in Example 1 to measure the graft ratio, ΔMR, and the strength of the constituent yarn before and after the forced test.

The results are shown in Table 1, from which ΔMR was 4
% Or more, the component yarn strength after the forced test is 2 g / dtex
The above woven fabric was obtained.

Embodiment 3 A circular cross section is divided into two parts by a line passing through the center, and one side is P
BT, the other is composed of PET, and PBT is a polyester-based composite fiber (75d,
36f) using a woven fabric (weave density: 104 × weft 81 /
inch, weight: 96 g / m ² ).

The woven fabric was treated in the same manner as in Example 1, and the graft ratio, ΔMR, and the strength of the constituent yarn before and after the forced test were measured.

The results are shown in Table 1, from which ΔMR was 4
% Or more, the component yarn strength after the forced test is 2 g / dtex
The above woven fabric was obtained.

Example 4 Fibers (50d, 24f) consisting only of PET and PBT
A woven fabric (woven density: 93 × 70 / weft / inch, basis weight: 123) using mixed yarn of fibers (50d, 24f) consisting of
g / m ² ).

The woven fabric was treated in the same manner as in Example 1, and the graft ratio, ΔMR, and the strength of the constituent yarn before and after the forced test were measured.

The results are shown in Table 1, from which ΔMR was 4
% Or more, the component yarn strength after the forced test is 2 g / dtex
The above woven fabric was obtained.

Comparative Example 1 A woven fabric (woven density: warp 104 × weft 81 / inch, basis weight: 96 g) using fibers (75d, 36f) consisting only of PET
/ M ² ).

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

The results are shown in Table 1. In this case, although the ΔMR was 4% or more, the component yarn strength after the forced test was 2 g.
/ Dtex or less.

Comparative Example 2 The same fabric as in Example 1 was used, except that the heat setting at 180 ° C. was not performed, and the fabric was treated in the same manner as in Example 1. Similarly, the graft ratio, ΔMR, and forced test were also performed. The strength of the component yarns before and after was measured.

The results are shown in Table 1. In this case, the ΔMR was 4% or more, but the component yarn strength after the forced test was 2 g.
/ Dtex or less.

[0052]

[Table 1]

[0053]

According to the present invention, an excellent modified polyester fiber, which has excellent hygroscopicity, does not decrease in strength, and does not generate wrinkles even when dyed, can be used in various garments. Of course, it can also be provided in the field of industrial materials.

Claims (13)

[Claims] (1) Polybutylene terephthalate or polypropylene terephthalate is not less than 20% of the fiber cross-sectional area.
%, 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. After being left for one week in an atmosphere of 80 ° C. and 65% RH, the operation of repeatedly performing washing 10 times is defined as one cycle, and the cycle is repeated three times. The component yarn strength after the compulsory test is 2 g / dtex. A modified polyester fiber structure characterized by the above. 2. The modified polyester fiber structure according to claim 1, wherein the polyester conjugate fiber is one in which polybutylene terephthalate or polypropylene terephthalate accounts for 20 to 45% of the fiber cross-sectional area. 3. A fiber comprising polybutylene terephthalate or polypropylene terephthalate in an amount of 20% or more.
The fiber structure comprising a polyester-based mixed yarn contained at a ratio of less than about 10% by weight, wherein the fiber structure is at 20 ° C.
The difference between the moisture content at 65% RH and the moisture content at 30 ° C. and 90% RH is 4% or more, and after being left for 1 week in an atmosphere of 80 ° C. and 65% RH, repeated washing 10 times The modified polyester fiber structure is characterized in that the constituent yarn strength after a forced test in which the above-mentioned operation is performed as one cycle and the cycle is repeated three times is 2 g / dtex or more. 4. The modified polyester fiber structure according to claim 3, wherein the polyester-based mixed yarn contains fibers made of polybutylene terephthalate or polypropylene terephthalate at a ratio of 20 to 45% by weight. 5. The modified polyester fiber structure according to claim 1, wherein said fiber structure is obtained by graft-polymerizing a hydrophilic vinyl monomer. 6. The modified polyester fiber structure according to claim 5, wherein said hydrophilic vinyl monomer contains a carboxyl group. 7. The modified polyester fiber structure according to claim 6, wherein said carboxyl group is substituted with a metal ion. 8. A polybutylene terephthalate or polypropylene terephthalate having a fiber cross-sectional area of at least 20%.
% Of a polyester-based composite fiber which is less than 10% by weight, and then heat-treated by applying an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator. Method. 9. The method for producing a modified polyester fiber structure according to claim 8, wherein said polyester conjugate fiber is one in which polybutylene terephthalate or polypropylene terephthalate accounts for 20 to 45% of the fiber cross-sectional area. 10. A fiber comprising polybutylene terephthalate or polypropylene terephthalate in an amount of 20% or more.
A modified polyester, which is subjected to a heat treatment of a fibrous structure made of a polyester-based mixed yarn containing less than 0% by weight, followed by applying an aqueous solution containing a hydrophilic vinyl monomer and a polymerization initiator, followed by heat treatment. A method for producing a fibrous structure. 11. The method for producing a modified polyester fiber structure according to claim 10, wherein said polyester-based mixed yarn contains fibers of polybutylene terephthalate or polypropylene terephthalate at a ratio of 20 to 45% by weight. Method. 12. The method according to claim 8, wherein said hydrophilic vinyl monomer contains a carboxyl group. 13. The modified polyester fiber structure according to claim 12, wherein a carboxyl group is replaced with a metal ion after applying an aqueous solution containing the hydrophilic vinyl monomer and a polymerization initiator and performing heat treatment. Manufacturing method.