JP2002061028A - Cross-linked fiber with good washing fastness and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyvinyl alcohol fiber excellent in hot water resistance and washing fastness. SOLUTION: This cross-linked fiber excellent in high washing fastness with a vinyl alcohol polymer (A) as at least one component is obtained by acetalization cross-linked reaction so that the cross-link density in the noncrystalline region of the polymer A meets a specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a conjugate fiber comprising a vinyl alcohol polymer as at least one component,
The present invention relates to a crosslinked fiber excellent in heat stability without causing agglutination or excessive shrinkage during high temperature dyeing or steam ironing, and excellent in washing fastness, and a method for producing the same.

[0002]

2. Description of the Related Art Fibers made of a vinyl alcohol polymer have excellent comfort characteristics in terms of hydrophilicity and antifouling properties because they have a hydroxyl group in the molecule. However, since the melting point of the polymer is low, it has a disadvantage that the thermal stability of high-temperature hot water, steam and the like is poor. For this reason, various proposals have been made to improve the dimensional stability by compounding the polymer with other thermoplastics, for example, polyester, polyamide, polyolefin and the like, to produce fibers (Japanese Patent Publication No. 56-5846). .

[0003] These proposals include high-temperature and high-pressure dyeing and sewing,
Or by using a steam iron, woven, knitted,
The olefin-vinyl alcohol copolymer exposed on the surface of textiles such as non-woven fabrics partially softens and micro-adheres, and the high-temperature heat during dyeing is used to prevent the texture of the textiles from becoming hard. A method of acetalizing a hydroxyl group of the polymer using a dialdehyde or the like before contact with water is also disclosed (Japanese Patent Publication No. 7-84681).

[0004] However, when the crosslinked fiber after the acetalization treatment is dyed with a disperse dye or the like,
In particular, when the crosslinked fiber has no enthalpy of crystallization, there is a problem that the washing fastness, particularly the washing liquid contamination, is poor. In addition, when the polymer has a crystallization enthalpy, there is also a problem that some products having poor washing fastness are found in terms of evaluation of washing fastness.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and comprises at least one vinyl alcohol-based polymer having excellent heat resistance, steam iron resistance and washing fastness. It is to provide a fiber that does.

[0006]

[Means for Solving the Problems]

That is, according to the present invention, in a fiber containing at least one component of a vinyl alcohol polymer (A) having a crosslinked structure, the crosslink density in an amorphous region in the polymer satisfies the following formula (1). A crosslinked fiber characterized by the following:

(Equation 3)

The present invention further provides an acetalization crosslinking reaction of a fiber containing at least one component of the vinyl alcohol polymer (A), and the crosslinking density in an amorphous region in the polymer is represented by the following formula (1). A method for producing a crosslinked fiber characterized by satisfying.

(Equation 4)

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polymer constituting a fiber comprising a vinyl alcohol-based polymer in the present invention is not limited to polyvinyl alcohol, but, for example, an olefin-vinyl alcohol-based copolymer obtained by introducing an olefin or the like by copolymerization. However, from the viewpoints of melt spinnability and fiber properties, an olefin-vinyl alcohol copolymer obtained by introducing an olefin as a copolymer component is preferably used.

As the olefin used in the olefin-vinyl alcohol copolymer, ethylene, propylene, butylene, pentene, hexene, heptene and the like can be used, but ethylene and propylene are copolymerized from the viewpoint of availability. A vinyl alcohol copolymer as a polymerization component is preferred, and an ethylene-vinyl alcohol copolymer is particularly preferred.

Next, a method for producing the vinyl alcohol polymer used in the present invention will be described. In a polymerization solvent such as methanol, vinyl acetate and, if necessary, olefins such as ethylene are used as copolymer components, radical polymerization is carried out under a radical polymerization catalyst, then unreacted monomers are expelled, and then saponification reaction is carried out with caustic soda. Awaken
After the vinyl alcohol-based polymer is formed, pelletized in water, washed with water and dried. The saponification degree of the vinyl alcohol polymer is preferably 95% or more. When the degree of saponification decreases, the crystallinity of the polymer decreases,
Not only does the fiber properties such as strength decrease, but also the polymer tends to soften, causing troubles in the processing step, and the feeling of the obtained fiber structure is unfavorably deteriorated.

As an example of an olefin-vinyl alcohol-based copolymer, an ethylene-vinyl alcohol-based copolymer is described.
It is preferably from 5 mol% to 70 mol%. 2
If the content is less than 5 mol%, that is, if the vinyl alcohol content is more than 75 mol%, breakage of single yarn and breakage during spinning or drawing are likely to occur, and it is difficult to obtain a flexible fiber. Further, as described later, in the case of using a high-melting polymer such as polyethylene terephthalate as the other thermoplastic polymer in the composite fiber composed of the polymer and another thermoplastic polymer, usually 25
A high spinning temperature of 0 ° C. or higher is used. In this case, if the ethylene content is less than 25 mol%, the heat resistance of the ethylene-vinyl alcohol copolymer becomes insufficient, and it is difficult to obtain a good conjugate fiber. Become.

On the other hand, if the ethylene content exceeds 70 mol%, the proportion of vinyl alcohol units, ie, hydroxyl groups, is necessarily reduced, and as a result, the proportion of the crosslinking reaction is reduced, and the desired effect of hot water resistance is reduced. Difficult to play.

In the method for producing a fiber comprising a vinyl alcohol polymer in the present invention, a known melt spinning apparatus can be used. That is, it is obtained by melt-kneading the pellets of the vinyl alcohol polymer with a melt extruder, guiding the molten polymer stream to the spinning head, measuring with a gear pump, and winding the yarn discharged from the spinning nozzle.

In the present invention, the polymer may be fiberized alone, or may be composite-spun with another thermoplastic polymer depending on the purpose. Such other thermoplastic polymers are preferably crystalline thermoplastic polymers having a melting point of 150 ° C. or higher in terms of heat resistance, dimensional stability, and the like, and include, for example, polyester, polyamide, and polypropylene. Can be.

Examples of the polyester include terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, phthalic acid, α, β- (4-carboxyphenoxy) ethane,
Aromatic dicarboxylic acids such as 4,4′-dicarboxydiphenyl, 5-sodium sulfoisophthalic acid or esters thereof, ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, Cyclohexane-1,
Examples thereof include polyesters synthesized from diols such as 4-dimethanol, polyethylene glycol and polytetramethylene glycol or ester-forming derivatives thereof, and polyesters such as polylactic acid. Among them, 80% or more of the structural units are ethylene. Polyesters that are terephthalate units or butylene terephthalate units are preferred. Further, such a polyester may contain a small amount of an additive, a fluorescent whitening agent, a stabilizer, and an ultraviolet absorber.

Examples of the polyamide include aliphatic polyamides containing nylon 6, nylon 66, and nylon 12 as main components and semi-aromatic polyamides. Polyamides containing a small amount of the third component may also be used. Such polyamide may contain a small amount of additives, fluorescent brighteners, stabilizers, ultraviolet absorbers and the like.

When a composite fiber of the vinyl alcohol polymer (A) and another thermoplastic polymer is used, the composite ratio of the two polymers is the former: the latter (mass ratio) = 10: 90 to 90: 1.
It is preferably 0 in view of spinnability. The composite form is not particularly limited as long as it is a conventionally known composite form such as a core-sheath, side-by-side, or laminated, but it is necessary that the polymer (A) is exposed on at least a part of the fiber surface. In order to make the polymer (A) exhibit the hydrophilic property and the feeling improvement property, it is preferable that 30% or more, more preferably 50% or more is exposed.

Next, a method for producing a fiber comprising a vinyl alcohol polymer having a crosslinked structure will be described in detail. As an example, a fiber made of an olefin-vinyl alcohol copolymer will be described. Generally, the fiber is subjected to acetalization crosslinking treatment using a dialdehyde and / or a ziraldehyde derivative as a crosslinking agent in order to improve hot water resistance. Done.

Examples of the cross-linking treatment method include ordinary processing methods such as a bath treatment method, a padding method, a coating method, a spray method, and an air current treatment method. Among them, the in-bath treatment method is preferable from the viewpoints of swelling of the fibers with water, easy dispersion of the crosslinking agent in the fibers, and uniformity of the crosslinking reaction.

Conventionally, the degree of crosslinking by dialdehyde and / or dialdehyde derivative is 1 to 100 when the number of vinyl alcohol units in the olefin-vinyl alcohol copolymer is 100. Assuming that 10% is provided, that is, all the reactive groups of the dialdehyde and / or the dialdehyde derivative have reacted with the hydroxyl group of the vinyl alcohol-based unit, the above four times, that is, 4 to 4 times the hydroxyl group
The cross-linking reaction was performed so as to be 0%.

Although the hot water resistance is improved by the acetalization crosslinking treatment, composite spinning is performed with an olefin-vinyl alcohol copolymer and a thermoplastic polymer such as polyester, and the composite fiber is dyed with a disperse dye or the like. If so, the washing fastness, especially the washing liquid contamination, is poor. As will be described later, in particular, when the acetalization crosslinking reaction is performed at a high temperature exceeding 120 ° C., after the treatment, the polymer may not have a crystal region, that is, may have no crystallization enthalpy. In this case, the hot water resistance was improved by satisfying the above degree of cross-linking, but the phenomenon of poor washing liquid contamination was observed. For this reason, the crosslinking reaction does not simply require that the degree of crosslinking satisfy a predetermined value.

Further, even when a crystalline region is present in the polymer (A), when a crosslinked fiber having a low degree of crosslinking is used, when a polyester or the like is used as the component (B), high-temperature dyeing is performed. In this case, there is also a problem that the crystal region of the component (A) is destroyed after dyeing, and the washing fastness is deteriorated.

[0024] These problems are caused by the fact that the non-crosslinked amorphous region present in the crosslinked product of the fiber has a large effect on the deterioration of the washing fastness, and it depends on the amount of the amorphous region present in the polymer. It is necessary to adjust the amount of crosslinking. In the present invention, the above-mentioned problem has been solved at once by defining the crosslinking density in the amorphous region by the following formula (1) and performing acetalization crosslinking treatment until the desired crosslinking density is satisfied.

(Equation 5)

In the present invention, the crosslink density is defined as the crosslink amount R of a vinyl alcohol-based polymer as shown by the formula (1).
m, the amount of vinyl alcohol Pm in the polymer, and the enthalpy of crystallization ΔH of the polymer after crosslinking. Here, the crosslinking amount Rm of the vinyl alcohol-based copolymer is defined by the mass increase rate ΔWt due to crosslinking and the number of linear methylene and / or methine groups contained in the crosslinked portion. The “straight chain” referred to herein indicates a bond between carbons having OR _{1 to 4} represented by the compound (1). The vinyl alcohol content Pm is a value defined by the composite ratio A of vinyl alcohol in the composite fiber and the copolymer modification amount m of the polymer. The enthalpy of crystallization ΔH of the polymer is a value obtained by measuring with a differential scanning calorimeter (DSC). In the present invention, when the crosslink density is equal to or more than a predetermined value, good washing fastness and feeling can be obtained. With the crosslinked fiber obtained by the present invention, a dyed product having a good washing fastness, particularly a washing liquid stain of 3 to 5 grades can be obtained.

The crosslinking density in the present invention must be 30 or more. If the density is less than 30, the washing fastness after dyeing will be poor. On the other hand, if the crosslink density exceeds 80, the color developability of the dyed product deteriorates, so that the density is preferably 80 or less.

Compounds used in the acetalization crosslinking treatment include glutaraldehyde, glyoxal, 1,9-
Dialdehydes such as nonandial are exemplified, but these dialdehydes are easily oxidized by oxygen in the air and have poor stability over time. Therefore, the reaction efficiency of acetalization using the dialdehyde is poor, and it is difficult to improve the crosslink density. Therefore, in the present invention, it is preferable to use a compound represented by the following general formula (1).

[0028]

Embedded image

In the formula, the alkyl group represented by R _{1 to} R ₄ is preferably an alkyl group having 1 to 4 carbon atoms, and among them, a methyl group is preferable from the viewpoint of ease of use. Further, the alkyl group may be substituted with an alkyleneoxy group such as an ethyleneoxy group. Further, all of R _{1 to} R ₄ may be the same type of alkyl group or may be different.
Further, when R ₁ and R ₂ and / or R ₃ and R ₄ are an alkylene group which forms a ring by bonding, the alkylene group is preferably an alkylene group having 1 to 4 carbon atoms, but the stability of the ring structure is high. In consideration of, a 5-membered ring or a 6-membered ring is preferable,
Therefore, an ethylene or propylene group having 2 to 3 carbon atoms is preferred. Any of these alkyl groups and alkylene groups may have a substituent.

In the formula represented by the general formula (1),
n is a value calculated in light of the composition ratio when treating using a plurality of compounds (1), and is not necessarily an integer. It is preferable that the compound (1) does not have a branched chain during the crosslinking treatment, and therefore, it is preferable that R ₅ be hydrogen. However, the compound (1) is, R ₅
May be a mixture of a compound having a so-called branched chain, which is an alkyl group having 1 to 4 carbon atoms, and a compound having no branched chain. It is more preferable to use only a compound having no branch or a mixture having a large ratio of a compound having no branch. Further, n in the compound (1) is 1 to 10
Is the number of The n groups of R ₅ include the same group, for example, even if they are all hydrogen, but also include, for example, a case where they are mixed such that the sum of the alkyl group and hydrogen is n. Further, the alkyl groups may be the same kind of group, or different kinds of groups may be mixed.

In the present invention, as the compound (1), only one kind of compound may be used, or a plurality of compounds having different n may be used as a mixture. When a mixture of compounds having different n is used, the average value of n in the compound is 1
It may be in the range of 10 to 10. In the present invention, compound (1)
Is preferably 5 to 9 in terms of the average value of n in the case of a mixture of the compound (1) from the viewpoint of the feeling of the crosslinked fiber product.

Preferred specific examples of compound (1) include:
1,1,6,6-tetramethoxyhexane, 1,1,
6,6-tetraethoxyhexane, 1,1,7,7-tetramethoxyheptane, 1,1,7,7-tetraethoxyheptane, 1,1,8,8-tetramethoxyoctane, 1,1,8, 8-tetraethoxyoctane, 1,
1,9,9-tetramethoxynonane, 1,1,9,9-
Tetraethoxynonane, 1,1,9,9-bisethylenedioxynonane, 1,1,9,9-bispropylenedioxynonane, 1,1,10,10-tetramethoxydecane, 1,1,10, 10-tetraethoxydecane, 1,
1,11,11-tetramethoxyundecane, 1,1,
11,11-tetraethoxyundecane and the like can be mentioned. These compounds may be used alone or in combination of two or more. Among them, 1,1,9,9-tetraalkoxynonane such as 1,1,9,9-tetraethoxynonane, 1,1,
1,9,9-bisethylenedioxynonane, 1,1,
1,1, such as 9,9-bispropylenedioxynonane
9,9-Bisalkylenedioxynonane is preferably used, and 1,1,9,9-bisethylenedioxynonane is particularly preferably used.

Of the above compounds, those hardly soluble in water may be used by emulsifying an anionic surfactant at a ratio of 2 to 25% by mass and a nonionic surfactant at a ratio of 2 to 30% by mass. Is preferred. Alkyl aryl sulfonates and / or polyoxyalkylene tristyryl phenyl ether sulfates are used as anionic surfactants, and castor oil alkylene oxide adducts and polyoxyalkylene polyhydric alcohol fatty acid moieties are used as nonionic surfactants. When one or more of the ester and the polyoxyalkylene tristyryl phenyl ether are used, the emulsion stability and the foaming suppressing effect of the compound (1) are improved. The concentration of the compound (1) is preferably 5 to 40% by mass, particularly preferably 2 to 40% by mass, based on the olefin-vinyl alcohol-based copolymer fiber to be treated.
0-30 mass% is preferable.

In the present invention, the acetalization crosslinking treatment is carried out by
The reaction is carried out under an acidic condition, and the acidity can be adjusted by an inorganic acid such as hydrochloric acid and sulfuric acid, and an organic acid such as acetic acid, formic acid, maleic acid, tartaric acid, lactic acid, citric acid, malic acid and succinic acid. Among them, an organic acid is preferably used in view of the corrosion resistance of the processing apparatus. Solid acids such as activated clay and ion exchange resins may be used in addition to the water-soluble acids.

The acetalization crosslinking treatment is preferably carried out under an acidic condition of pH = 1 to 5. Treatment under a strong acid at a pH of less than 1 causes a problem of coloring and yellowing, and a problem of poor light resistance. On the other hand, in the treatment at a pH exceeding 5, if the treatment conditions such as the treatment temperature and the treatment time are not severe, the acetalization becomes insufficient and the crosslink density cannot be improved. From the viewpoint of acetalization and crosslinking treatment, p
H is preferably 2 to 4.

In order to perform the acetalization crosslinking treatment to obtain a desired crosslinking density, the treatment temperature is preferably from 90 ° C. to 120 ° C. At a processing temperature of less than 90 ° C., in the above-mentioned pH range, the acetalization rate becomes extremely slow.
Crosslinking due to acetalization becomes insufficient, and it is difficult to obtain a desired crosslink density. On the other hand, if the processing temperature exceeds 120 ° C., the fibers may undergo excessive shrinkage, and the feeling of the fabric may be impaired.

The dyeing treatment can be performed simultaneously with the acetalization crosslinking treatment. At that time, if a dye having good acid resistance is not selected, the coloring property of the dye may be deteriorated. After the acetalization, a usual dyeing treatment can also be performed.

The form of the fiber to be treated in the present invention is not particularly limited, and examples thereof include cotton, short fiber, long fiber,
It may be in any form of skein, cloth, mesh, clothing and other textile products, but the treatment is performed in the form of a woven or knitted fabric made of the fiber, or a woven or knitted fabric containing the fiber, or a nonwoven fabric. Is preferred in terms of process and ease of operation.

[0039]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. The measured values in the examples are measured by the following method. (1) Mass increase rate (mass%) The cloth after the cross-linking treatment was dried at 60 ° C. under reduced pressure (133 Pa).
For 12 hours, and the weight W after absolute drying was measured. Also,
The fabric before the cross-linking treatment is dried at 60 ° C. under reduced pressure (133 Pa).
For 12 hours, and the weight after absolute drying was defined as W ₀ , and the difference (W−W ₀ ) was defined as the weight increase rate of the crosslinking agent. (2) Enthalpy of crystallization (J / g) Measured by a differential scanning calorimeter (DSC) under the following conditions, and shown as an endothermic peak area. Measurement conditions: Left at 35 ° C. for 1 minute, and then heated to 300 ° C. at a rate of 10 ° C./min. When the sample was a composite fiber, the measurement was performed as it was, and the peak on the low temperature side was ethylene-
The peak of the vinyl alcohol copolymer was used. (4) Washing fastness (washing liquid contamination) Measurement and evaluation were performed in accordance with JIS L 0844 (A-2 method). (5) Hand The dry fabric after the cross-linking treatment was touched with a hand, examined, and evaluated based on the following criteria. ：: Soft texture without sticking. Δ: Micro-adhesion was observed and slightly cured. ×: Agglutination was observed and the composition was cured.

Examples 1-3 and Comparative Examples 1-2 Using methanol as a polymerization solvent, radical polymerization of ethylene and vinyl acetate was carried out at 60 ° C. to give an ethylene content of 4
A 4 mol% random polymer was prepared, and then saponified with caustic soda to obtain a saponified ethylene-vinyl acetate copolymer having a degree of saponification of 99% or more, and a small amount of acetic acid was added to the wet polymer. The washing was repeated with a large excess of pure water to reduce the content of alkali metal ions of K and Na and the content of alkaline earth metal ions of Mg and Ca in the polymer to about 10 ppm or less, respectively. After separating water, vacuum drying was sufficiently performed at 100 ° C. or less to obtain an intrinsic viscosity [η] = 1.05 dl / g (8
(Measured at 30 ° C. using 5% aqueous phenol as a solvent) to obtain a polymer. As a thermoplastic polymer, [η] 0.62 dl
/ G (measured with a Ubbelohde viscometer in a thermostat at 30 ° C using a mixed solvent of equal amounts of phenol and tetrachloroethane as a solvent), using an ethylene-vinyl alcohol copolymer (A). And polyethylene terephthalate (B) at a composite ratio of A / B = 1
/ 1 core-sheath conjugate fiber was obtained (A forms a sheath portion, and B forms a core portion). Winding was performed at a spinning temperature of 260 ° C. and a spinning speed of 1000 m / min. The obtained spun yarn is stretched to 83 dtex /
A composite filament of 24f was obtained. Thereafter, a knitted fabric was produced using the composite filament.

The knitted fabric was mixed with 1 g / l of sodium hydroxide and 0.5 g / l of Actinol R-100 (manufactured by Matsumoto Yushi Co., Ltd.).
The mixture was desizing at 80 ° C. for 30 minutes. Then, it was preset at 145 ° C. with a pin tenter. Thereafter, 1,1,9,9-bisethylenedioxynonane (BEN) was used as a crosslinking agent, and the crosslinking agent was mixed at a ratio shown in Table 1 to prepare a crosslinking agent. Thereafter, acetalization crosslinking treatment was performed with a crosslinking treatment agent. Then, staining and reduction washing were performed under the following conditions. Then, a final set was performed at 145 ° C. After the final setting, the knitted fabric was evaluated for washing fastness and the like. Table 2 shows the results.

[0042]

[Table 1]

Cross-linking treatment conditions: Cross-linking treatment agent (emulsion composition such as BEN) listed in Table 2 Meister SA (anionic surfactant: manufactured by Meisei Chemical Industry) 1 g / L (pH adjusted by maleic acid or the like) 115 × 40 minutes

Dyeing conditions: Kayalon Polyester Navy Blue TK-SF200 2% by mass Disper TL (manufactured by Meisei Chemical Industry) 1 g / L acetic acid 0.5 mL / L Bath ratio 1:20 Temperature 115 ° C. × 40 minutes

Reduction washing: Sodium hydroxide 1 g / L Amirapine D (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1 g / L hydrosulfite 1 g / L Bath ratio 1:20 Temperature 80 ° C. × 20 minutes

[0046]

[Table 2]

As is clear from Table 2, the crosslink density was 30
With respect to the above, the washing fastness was as good as grade 3 or more, and a good feeling was obtained. On the other hand, those having a crosslinking density of less than 30 exhibited poor washing fastness.

From the above results, the fiber having good washing fastness can be obtained by setting the crosslink density of the fiber made of the vinyl alcohol polymer and performing the crosslink so that the fiber has a predetermined crosslink density. It turns out that the product is obtained.

Claims (8)

[Claims] 1. A fiber comprising at least one component of a vinyl alcohol polymer (A) having a crosslinked structure, wherein the crosslink density in an amorphous region in the polymer satisfies the following formula (1). Cross-linked fibers. (Equation 1) 2. The fiber according to claim 1, wherein the polymer (A) is an olefin-vinyl alcohol copolymer. 3. The polymer (A) having an ethylene content of 25 to 25.
The fiber according to claim 1 or 2, which is a 70 mol% ethylene-vinyl alcohol copolymer. 4. A fiber comprising a polymer (A) and another thermoplastic polymer (B), wherein the polymer (A) is exposed on at least a part of the fiber surface. The fiber according to claim 1. 5. A fiber containing at least one component of a vinyl alcohol polymer (A) is subjected to an acetalization crosslinking reaction, and a crosslinking density in an amorphous region in the polymer satisfies the following formula (1). A method for producing a crosslinked fiber, characterized in that: (Equation 2) 6. The method according to claim 5, wherein the polymer (A) is an olefin-vinyl alcohol copolymer. 7. The polymer (A) having an ethylene content of 25 to 7
The production method according to claim 5 or 6, which is a 0 mol% ethylene-vinyl alcohol copolymer. 8. A fiber comprising a polymer (A) and another thermoplastic polymer (B), wherein the polymer (A) is exposed on at least a part of the fiber surface. The method according to claim 5.