JP6177045B2 - Composite fiber made of modified ethylene-vinyl alcohol copolymer - Google Patents

Description

  The present invention relates to a fiber product such as a composite fiber, a thread, and a fabric, which has a good texture and is composed of a modified ethylene-vinyl alcohol copolymer dyeable as a reactive dye, and a method for producing the same.

  A fiber made of an ethylene-vinyl alcohol copolymer (hereinafter sometimes abbreviated as EVOH) has been known. Japanese Patent Publication No. 56-5846 (Patent Document 1) discloses a composite fiber obtained by spinning and joining a hydrophobic thermoplastic resin and EVOH having an ethylene content of 15 to 50 mol% and a saponification degree of 98.5 mol% or more. Have been described. EVOH alone has insufficient hot water resistance and low elongation. By using such a composite structure, excellent dyeability and antistatic properties can be achieved without significantly degrading various properties of hydrophobic thermoplastic resins. It is said that sex can be imparted. In the examples of the publication, examples of core-sheath type composite fibers having polyethylene terephthalate as a core and EVOH as a sheath are described.

  Japanese Patent Application Laid-Open No. 50-12186 (Patent Document 2) describes 0.01 to 0.8 to 100 parts by weight of EVOH having an ethylene content of 20 to 90 mol% and a saponification degree of 95% or more. Disclosed is a method for producing an EVOH-modified product having improved molding processability, which comprises reacting a part by weight of a polyvalent epoxy compound. This publication also describes that such EVOH-modified products can be mixed with other resins such as unmodified EVOH and polyolefin.

  Japanese Patent Application Laid-Open No. 11-217724 (Patent Document 3) discloses an ethylene-vinyl alcohol copolymer in which 0.05 to 1.0 mol% of sodium 2-acrylamido-2-methylpropanesulfonate is contained in the main chain. Disclosed is a composite fiber having a copolymerized modified ethylene-vinyl alcohol copolymer as a sheath component and another thermoplastic polymer as a core component, and having a K / S of 20 or more when treated with a cationic dye. ing.

Japanese Patent Publication No.56-5846 Japanese Patent Laid-Open No. 50-12186 Japanese Patent Laid-Open No. 11-217724

  The object of the present invention is to maintain a good texture similar to natural fibers that are soft and bulky, and to have excellent color development after dyeing with reactive dyes while maintaining a good texture and hygroscopicity and water absorption. In other words, it is possible to easily obtain a synthetic fiber capable of expressing light collecting properties without causing trouble or undesirable coloring of the fiber in the polymer design, fiberizing process, and further in the post-processing process.

  As a result of intensive studies to solve the above problems, the present inventors obtained a copolymer having a specific amount of a monomer having a specific structure as a third component in the main chain of the ethylene-vinyl alcohol copolymer, and obtained. The present inventors have found that the above problems can be achieved by using a composite fiber containing a copolymer as one component, and completed the present invention.

That is, the present invention is a copolymer of the monomer that is represented by the following formula (I) is a random copolymer, a relative total monomer units, the content of b and c (mol%) of A modified ethylene-vinyl alcohol copolymer satisfying the following formulas (1) to (3) and having a saponification degree (DS) defined by the following formula (4) of 90 mol% or more is used as a component. This is a composite fiber comprising a thermoplastic resin other than an ethylene-vinyl alcohol copolymer as another component.

[In Formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the alkyl group contains a hydroxyl group, an alkoxy group or a halogen atom. But you can. X, Y and Z each independently represent a hydrogen atom, a formyl group or an alkanoyl group having 2 to 10 carbon atoms. ]
18 ≦ a ≦ 55 (1)
0.01 ≦ c ≦ 20 (2)
[100− (a + c)] × 0.9 ≦ b ≦ [100− (a + c)] (3)
DS = [(total number of moles of hydrogen atoms among X, Y and Z) / (total number of moles of X, Y and Z)] × 100 (4)

  The present invention is preferably a composite fiber comprising the modified ethylene-vinyl alcohol copolymer as a component, wherein the thermoplastic resin is polyester.

The present invention is preferably a composite fiber comprising the modified ethylene-vinyl alcohol copolymer as a component, wherein R ¹ , R ² , R ³ and R ⁴ are hydrogen atoms.

  The present invention is preferably a composite fiber formed by using the modified ethylene-vinyl alcohol copolymer as a component, wherein X, Y and Z are each independently a hydrogen atom or an acetyl group.

  The present invention is a fiber product including a composite fiber composed of the modified ethylene-vinyl alcohol copolymer as one component.

  According to the present invention, a composite fiber having good process passability during spinning and drawing operations and good hygroscopicity and dyeability can be obtained. Moreover, the fiber product obtained using this composite fiber has good hygroscopicity and excellent wearing feeling.

2 is a ¹ H-NMR spectrum of a modified EVAc obtained in Synthesis Example 1. 2 is a ¹ H-NMR spectrum of a modified EVOH obtained in Synthesis Example 1.

The composite fiber of the present invention is a composite fiber comprising a fiber composed of a resin composition of a modified ethylene-vinyl alcohol copolymer and another thermoplastic resin as one component and another thermoplastic resin as the other component. It is characterized by being. First, the modified ethylene-vinyl alcohol copolymer (hereinafter sometimes abbreviated as modified EVOH) used in the present invention will be described.
The modified EVOH is a copolymer of the monomer that is represented by the following formula (I) is a random copolymer, the content of a, b and c for the total monomer units (mol%) is below The modified EVOH satisfies the formulas (1) to (3) and has a saponification degree (DS) defined by the following formula (4) of 90 mol% or more. This modified EVOH has a monomer unit having a 1,3-diol structure in the main chain of the copolymer in addition to the ethylene unit and the vinyl alcohol unit, so that the dyeability is further improved and dyed with a reactive dye. It becomes possible.

[In Formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the alkyl group contains a hydroxyl group, an alkoxy group or a halogen atom. But you can. X, Y and Z each independently represent a hydrogen atom, a formyl group or an alkanoyl group having 2 to 10 carbon atoms. ]

In the formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R ¹ , R ² , R ³ and R ⁴ may be the same group or different. The structure of the alkyl group is not particularly limited, and may partially have a branched structure or a cyclic structure. The alkyl group may contain a hydroxyl group, an alkoxy group or a halogen atom. R ¹ , R ² , R ³ and R ⁴ are preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom from the viewpoint of dyeability. Preferred examples of the alkyl group include linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, and pentyl group. Can be mentioned.

  In the formula (I), X, Y and Z each independently represent a hydrogen atom, a formyl group or an alkanoyl group having 2 to 10 carbon atoms. When X, Y or Z is a hydrogen atom, the formula (I) has a hydroxyl group, and when X, Y or Z is a formyl group or an alkanoyl group, the formula (I) has an ester group. . The alkanoyl group is preferably an alkanoyl group having 2 to 5 carbon atoms, and an acetyl group, a propanoyl group, a butanoyl group, and the like are preferred. Among these, an acetyl group is more preferable in terms of hygroscopicity. Furthermore, from the viewpoint of hygroscopicity and dyeability, it is particularly preferable that all of X, Y and Z are hydrogen atoms or a mixture containing hydrogen atoms.

  The monomer unit containing X is usually obtained by saponifying a vinyl ester. Therefore, X is preferably a mixture of a hydrogen atom and a formyl group or an alkanoyl group having 2 to 10 carbon atoms. Considering the availability of the monomer (vinyl acetate) and the production cost, it is particularly preferable that X is a mixture of a hydrogen atom and an acetyl group.

  On the other hand, the monomer unit containing Y and Z can be produced by copolymerization of an unsaturated monomer unit having a 1,3-diester structure and then saponification, or a 1,3-diol structure. It can also be produced by copolymerizing the unsaturated monomer unit as it is. Therefore, both Y and Z may be a hydrogen atom alone, or a mixture of a hydrogen atom and a formyl group or an alkanoyl group having 2 to 10 carbon atoms, more preferably a mixture of a hydrogen atom and an acetyl group. It may be. When both Y and Z are only hydrogen atoms, a fiber having particularly good dyeability (color development) can be obtained.

In the modified EVOH used to form the fiber of the present invention, the content (mol%) of a, b and c with respect to all monomer units satisfies the following formulas (1) to (3).
18 ≦ a ≦ 55 (1)
0.01 ≦ c ≦ 20 (2)
[100− (a + c)] × 0.9 ≦ b ≦ [100− (a + c)] (3)

  a shows the content rate (mol%) of the ethylene unit with respect to all the monomer units, and is 18-55 mol%. When the ethylene content is less than 18 mol%, the melt moldability of the modified EVOH is deteriorated. From the viewpoint of obtaining a fiber excellent in spinnability, stretchability and strength, a is preferably 22 mol% or more, particularly preferably 25 mol% or more, and more preferably 31 mol% or more. is there. On the other hand, from the viewpoint of obtaining fibers excellent in hygroscopicity and comfort, a is preferably 50 mol% or less, and more preferably 45 mol% or less. When ethylene content exceeds 55 mol%, there exists a possibility of damaging the texture as EVOH fiber. From the above, when the contained ethylene content is within the range of the above formula (1), a fiber excellent in spinnability, stretchability, dyeability and hygroscopicity can be obtained.

  c represents the content (mol%) of the monomer unit containing Y and Z shown at the right end in the formula (I) with respect to all monomer units, and 0.01 to 20 mol %. If c is less than 0.01 mol%, the dyeability and hygroscopicity of the modified EVOH will be insufficient. c is preferably 0.1 mol% or more, and more preferably 0.5 mol% or more. On the other hand, if c exceeds 20 mol%, the crystallinity is extremely lowered, and the spinnability and stretchability are insufficient. c is preferably 10 mol% or less, and more preferably 5 mol% or less.

b shows the content rate (mol%) of the vinyl alcohol unit and the vinyl ester unit with respect to all the monomer units. This satisfies the following formula (3).
[100− (a + c)] × 0.9 ≦ b ≦ [100− (a + c)] (3)
That is, in the modified EVOH of the present invention, 90% or more of the monomer units other than the ethylene units and the monomer units containing Y and Z shown at the right end in the formula (I) are vinyl alcohol units or It is a vinyl ester unit. More preferably, the following formula (3 ′) is satisfied, and further preferably, the following formula (3 ″) is satisfied.
[100− (a + c)] × 0.95 ≦ b ≦ [100− (a + c)] (3 ′)
[100− (a + c)] × 0.98 ≦ b ≦ [100− (a + c)] (3 ″)
These a, b, and c are calculated from the ¹ H-NMR spectrum of modified EVAAc as shown in FIG.

The modified EVOH used to form the fiber of the present invention has a saponification degree (DS) defined by the following formula (4) of 90 mol% or more.
DS = [(total number of moles of hydrogen atoms among X, Y and Z) / (total number of moles of X, Y and Z)] × 100 (4)
Here, “the total number of moles of hydrogen atoms among X, Y and Z” indicates the number of moles of hydroxyl groups, and “the total number of moles of X, Y and Z” is the total number of moles of hydroxyl groups and ester groups. Indicates. When the saponification degree (DS) is less than 90 mol%, the thermal stability becomes insufficient, and gels and blisters are likely to occur during spinning. The saponification degree (DS) is preferably 95 mol% or more, more preferably 98 mol% or more, and even more preferably 99 mol% or more.

  The degree of saponification (DS) can be obtained by a nuclear magnetic resonance (NMR) method. The content of the monomer units represented by a, b and c can also be obtained by the NMR method. The modified EVOH used in the present invention is usually a random copolymer. The fact that it is a random copolymer can be confirmed from NMR and melting point measurement results.

  The preferred melt flow rate (MFR) (190 ° C., 2160 g load) of the modified EVOH used to form the fibers of the present invention is 0.1-30 g / 10 min, more preferably 0.3-25 g. / 10 minutes, more preferably 0.5 to 20 g / 10 minutes. However, those having a melting point near 190 ° C. or exceeding 190 ° C. were measured under a load of 2160 g and at a plurality of temperatures above the melting point, and in a semi-logarithmic graph, the reciprocal absolute temperature was plotted on the horizontal axis and the logarithm of MFR on the vertical axis, The value is extrapolated to 190 ° C.

  Here, when the modified EVOH is composed of a mixture of two or more different modified EVOH, the content, saponification degree, and MFR of the monomer units represented by a, b, and c are calculated from the blending weight ratio. Average value is used.

  The production method of the modified EVOH used for forming the fiber of the present invention is not particularly limited. For example, a modified ethylene-vinyl ester copolymer represented by the following formula (IV) by radical polymerization of ethylene, a vinyl ester represented by the following formula (II), and an unsaturated monomer represented by the following formula (III) The method of saponifying it after obtaining is mentioned.

In formula (II), R ⁵ represents a hydrogen atom or an alkyl group having 1 to 9 carbon atoms. The number of carbon atoms of the alkyl group is preferably 1 to 4. Examples of the vinyl ester represented by the formula (II) include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, and vinyl caproate. From the economical viewpoint, vinyl acetate is particularly preferred.

In formula (III), R ¹ , R ² , R ³ and R ⁴ are the same as in formula (I). R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group having 1 to 9 carbon atoms. The number of carbon atoms of the alkyl group is preferably 1 to 4. Examples of the unsaturated monomer represented by the formula (III) include 2-methylene-1,3-propanediol diacetate, 2-methylene-1,3-propanediol dipropionate, 2-methylene-1,3- Examples thereof include propanediol dibutyrate. Among these, 2-methylene-1,3-propanediol diacetate is preferably used from the viewpoint of easy production. In the case of 2-methylene-1,3-propanediol diacetate, R ¹ , R ² , R ³ and R ⁴ are hydrogen atoms, and R ⁶ and R ⁷ are methyl groups.

In the formula (IV), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , a, b and c are the same as those in the formulas (I) to (III). The modified ethylene-vinyl ester copolymer thus obtained is a novel polymer and then saponified.

  Further, instead of the unsaturated monomer represented by the above formula (III), an unsaturated monomer represented by the following formula (V) may be copolymerized. Only the unit derived from the unsaturated monomer represented by (II) is saponified.

In formula (V), R ¹ , R ² , R ³ and R ⁴ are the same as in formula (I). Examples of the unsaturated monomer represented by the formula (V) include 2-methylene-1,3-propanediol.

  Since the unsaturated monomer represented by the formula (III) and the formula (V) used in the present invention has high copolymerization reactivity with the vinyl ester monomer, the copolymerization reaction easily proceeds. Therefore, it is easy to increase the amount of modification and the degree of polymerization of the resulting modified ethylene-vinyl ester copolymer. In addition, even if the polymerization reaction is stopped at a low polymerization rate, the amount of unreacted unsaturated monomer remaining at the end of the polymerization is small, which is excellent in terms of environment and cost. In this respect, the unsaturated monomer represented by the formula (III) and the formula (V) has one carbon atom having a functional group at the allylic position, such as allyl glycidyl ether or 3,4-diacetoxy-1-butene. It is only better than other monomers. Here, the unsaturated monomer represented by the formula (III) has higher reactivity than the unsaturated monomer represented by the formula (V).

  Copolymerized ethylene with a vinyl ester represented by the above formula (II) and an unsaturated monomer represented by the above formula (III) or (V) to produce a modified ethylene- represented by the above formula (IV) The polymerization method for producing the vinyl ester copolymer may be any of batch polymerization, semi-batch polymerization, continuous polymerization, and semi-continuous polymerization. Moreover, as a polymerization method, well-known methods, such as a block polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method, are employable. A bulk polymerization method or a solution polymerization method in which polymerization proceeds in a solvent-free or solvent such as alcohol is usually employed. In order to obtain a modified ethylene-vinyl ester copolymer having a high degree of polymerization, the use of an emulsion polymerization method is one of the options.

  Although the solvent used in the solution polymerization method is not particularly limited, alcohol is preferably used. For example, lower alcohols such as methanol, ethanol, and propanol are more preferably used. The amount of solvent used in the polymerization reaction solution may be selected in consideration of the viscosity average polymerization degree of the target modified EVOH and the chain transfer of the solvent, and the weight ratio of the solvent and the total monomers contained in the reaction solution. (Solvent / Total monomer) is selected from the range of 0.01 to 10, preferably 0.05 to 3.

  The polymerization initiator used when copolymerizing ethylene, the vinyl ester represented by the above formula (II), and the unsaturated monomer represented by the above formula (III) or (V) is a known polymerization. The initiator is selected from azo initiators, peroxide initiators, and redox initiators depending on the polymerization method. Examples of the azo initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), and 2,2′-azobis (4-methoxy-2,4). -Dimethylvaleronitrile). Examples of the peroxide initiator include percarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, diethoxyethyl peroxydicarbonate; t-butylperoxyneodecanate, α -Perester compounds such as cumylperoxyneodecanate and acetyl peroxide; acetylcyclohexylsulfonyl peroxide; 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate and the like. Potassium persulfate, ammonium persulfate, hydrogen peroxide, or the like may be used in combination with the above initiator. The redox initiator is, for example, a polymerization initiator in which the peroxide initiator is combined with a reducing agent such as sodium hydrogen sulfite, sodium hydrogen carbonate, tartaric acid, L-ascorbic acid, or longalite. The amount of the polymerization initiator used varies depending on the polymerization catalyst and cannot be determined unconditionally, but is adjusted according to the polymerization rate. The amount of the polymerization initiator used is preferably 0.01 to 0.2 mol% and more preferably 0.02 to 0.15 mol% with respect to the vinyl ester monomer. The polymerization temperature is not particularly limited, but is suitably about room temperature to 150 ° C, preferably 40 ° C or higher and lower than the boiling point of the solvent used.

  When ethylene is copolymerized with the vinyl ester represented by the above formula (II) and the unsaturated monomer represented by the above formula (III) or (V), the effect of the present invention is not inhibited. If present, it may be copolymerized in the presence of a chain transfer agent. Examples of the chain transfer agent include aldehydes such as acetaldehyde and propionaldehyde; ketones such as acetone and methyl ethyl ketone; mercaptans such as 2-hydroxyethanethiol; phosphinic acid salts such as sodium phosphinate monohydrate and the like. . Of these, aldehydes and ketones are preferably used. The amount of the chain transfer agent added to the polymerization reaction solution is determined according to the chain transfer coefficient of the chain transfer agent and the degree of polymerization of the target modified ethylene-vinyl ester copolymer. 0.1-10 mass parts is preferable with respect to a mass part.

  The modified ethylene-vinyl ester copolymer thus obtained can be saponified to obtain a modified EVOH used to form the fiber of the present invention. At this time, the vinyl ester unit in the copolymer is converted into a vinyl alcohol unit. In addition, the ester bond derived from the unsaturated monomer represented by the formula (III) is simultaneously hydrolyzed and converted into a 1,3-diol structure. Thus, different types of ester groups can be simultaneously hydrolyzed by a single saponification reaction.

  As a saponification method of the modified ethylene-vinyl ester copolymer, a known method can be adopted. The saponification reaction is usually performed in a solution of alcohol or hydrous alcohol. The alcohol preferably used at this time is a lower alcohol such as methanol or ethanol, and particularly preferably methanol. The alcohol or hydrous alcohol used in the saponification reaction may contain other solvents such as acetone, methyl acetate, ethyl acetate, and benzene as long as the weight is 40% by weight or less. The catalyst used for the saponification is, for example, an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide, an alkali catalyst such as sodium methylate, or an acid catalyst such as mineral acid. The temperature at which saponification is performed is not limited, but a range of 20 to 120 ° C. is preferable. When a gel-like product is precipitated as the saponification proceeds, the product is pulverized, washed and dried to obtain a modified EVOH.

The saponification degree of the modified ethylene-vinyl ester copolymer used in the present invention is preferably 90% or more. The saponification degree of the modified ethylene-vinyl ester copolymer is more preferably 95% or more, further preferably 98% or more, and optimally 99% or more. If the degree of saponification is less than 90%, the thermal stability becomes insufficient, and gels and blisters are likely to occur, which may deteriorate the process passability.

  The modified EVOH used to form the conjugate fiber of the present invention is ethylene, vinyl ester represented by the above formula (II), and the above formula (III) or (V) as long as the effects of the present invention are not inhibited. A structural unit derived from another ethylenically unsaturated monomer copolymerizable with the unsaturated monomer represented by Examples of such ethylenically unsaturated monomers include α-olefins such as propylene, n-butene, isobutylene, and 1-hexene; acrylic acid and salts thereof; unsaturated monomers having an acrylate group. Methacrylic acid and salts thereof; unsaturated monomer having a methacrylic ester group; acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetone acrylamide, acrylamide propanesulfonic acid and salts thereof; Acrylamidepropyldimethylamine and salts thereof (eg, quaternary salts); methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and salts thereof, methacrylamidepropyldimethylamine and salts thereof (eg Grade salt); methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether, 2,3-diacetoxy-1-vinyl Vinyl ethers such as oxypropane; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride and vinyl fluoride; vinylidene halides such as vinylidene chloride and vinylidene fluoride; allyl acetate, 2, Allyl compounds such as 3-diacetoxy-1-allyloxypropane and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid and salts or esters thereof; vinyltrimethoxy Examples thereof include vinylsilyl compounds such as silane; isopropenyl acetate and the like.

  Other components can be blended with the modified EVOH used to form the conjugate fiber of the present invention to form a resin composition. For example, other thermoplastic resins, plasticizers, lubricants, stabilizers, surfactants, colorants, UV absorbers, antistatic agents, drying agents, crosslinking agents, metal salts, fillers, reinforcing agents for various fibers, etc. It can also be set as the resin composition which mix | blended.

  Especially, it is preferable that modified | denatured EVOH used for forming the composite fiber of this invention contains an alkali metal salt. The cation species of the alkali metal salt is not particularly limited, but sodium salt and potassium salt are preferable. The anionic species of the alkali metal salt is not particularly limited. It can be added as a carboxylate, carbonate, bicarbonate, phosphate, hydrogen phosphate, borate, hydroxide or the like. The content of the alkali metal salt is preferably 10 to 500 ppm in terms of alkali metal element. When the content of the alkali metal salt is less than 10 ppm, interlayer adhesion may be insufficient, and more preferably 50 ppm or more. On the other hand, when the content of the alkali metal salt exceeds 500 ppm, the melt stability may be insufficient, and is more preferably 300 ppm or less.

  It is also preferred that the modified EVOH used to form the conjugate fiber of the present invention contains a phosphate compound. Thus, by setting it as the resin composition containing a phosphoric acid compound, the coloring at the time of melt molding can be prevented. The phosphoric acid compound used for this invention is not specifically limited, Various acids, such as phosphoric acid and phosphorous acid, its salt, etc. can be used. The phosphate may be contained in any form of a first phosphate, a second phosphate, and a third phosphate, but the first phosphate is preferable. The cationic species is not particularly limited, but is preferably an alkali metal salt. Among these, sodium dihydrogen phosphate and potassium dihydrogen phosphate are preferable. The content of the phosphate compound is preferably 5 to 200 ppm in terms of phosphate radical. When the content of the phosphoric acid compound is less than 5 ppm, coloring resistance at the time of melt molding may be insufficient. On the other hand, when the content of the phosphoric acid compound exceeds 200 ppm, the melt stability may become insufficient, and is more preferably 160 ppm or less.

  The modified EVOH used to form the composite fiber of the present invention may contain a boron compound. Thus, by setting it as the resin composition containing a boron compound, the torque fluctuation at the time of heat-melting can be suppressed. The boron compound used in the present invention is not particularly limited, and examples thereof include boric acids, boric acid esters, borates, and borohydrides. Specific examples of boric acids include orthoboric acid, metaboric acid, and tetraboric acid. Examples of boric acid esters include triethyl borate and trimethyl borate. Examples include alkali metal salts of acids, alkaline earth metal salts, and borax. Among these compounds, orthoboric acid (hereinafter sometimes simply referred to as boric acid) is preferable. The content of the boron compound is preferably 20 to 2000 ppm or less in terms of boron element. When the content of the boron compound is less than 20 ppm, suppression of torque fluctuation during heating and melting may be insufficient, and more preferably 50 ppm or more. On the other hand, when the content of the boron compound exceeds 2000 ppm, gelation tends to occur and the moldability may deteriorate, and more preferably 1000 ppm or less.

  Further, in the range where the effect of the present invention is not inhibited, in order to improve the melt stability and the like, hydrotalcite compounds, hindered phenols, hindered amine heat stabilizers, metal salts of higher aliphatic carboxylic acids (for example, One or more of calcium stearate, magnesium stearate, etc.) may be contained in the modified EVOH used to form the composite fiber of the present invention in an amount of 0.001 to 1% by weight. Specific examples of other components include the following.

  Antioxidant: 2,5-di-t-butyl-hydroquinone, 2,6-di-t-butyl-p-cresol, 4,4′-thiobis- (6-t-butylphenol), 2,2′- Methylene-bis- (4-methyl-6-tert-butylphenol), octadecyl-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate, 4,4′-thiobis- (6 -T-butylphenol) and the like.

  UV absorber: ethylene-2-cyano-3 ′, 3′-diphenyl acrylate, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-t-butyl) -5'-methylphenyl) 5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone and the like.

  Plasticizer: dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphate ester, etc.

  Antistatic agents: pentaerythritol monostearate, sorbitan monopalmitate, sulfated polyolefins, polyethylene oxide, carbowax and the like.

  Lubricant: ethylene bisstearamide, butyl stearate, etc.

  Colorant: Carbon black, phthalocyanine, quinacridone, indoline, azo pigment, Bengala, etc.

  Filler: titanium oxide, silicon oxide, ballastite, calcium silicate, etc.

  In the present invention, it is important from the viewpoint of passing through the spinning process that the composite fiber is composed of a modified EVOH as one component and a thermoplastic resin other than the modified EVOH as another component.

  As the thermoplastic resin combined with the modified EVOH, it is preferable to use a crystalline thermoplastic polymer having a melting point of 150 ° C. or higher from the viewpoint of heat resistance and dimensional stability, and a typical example thereof is a fiber-forming polyester. , Polyamide, polyolefin, polyvinyl chloride and the like. Of these, polyester is preferable from the viewpoint of versatility.

The polyester used as the thermoplastic resin in the present invention is not particularly limited. For example, poly (ethylene terephthalate), poly (butylene terephthalate), poly (ethylene terephthalate / isophthalate), poly (ethylene glycol / cyclohexanedimethanol / terephthalate) and the like are exemplified as suitable ones. Among these, poly (ethylene terephthalate) is particularly preferable. In addition, as the polyester, diols such as ethylene glycol, butylene glycol, cyclohexanedimethanol, neopentyl glycol, pentanediol, or isophthalic acid, benzophenone dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenylmethane dicarboxylic acid, propylene bis. (Phenylcarboxylic acid), diphenyl oxide dicarboxylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, diethyl succinic acid and other polyesters containing dicarboxylic acid It is also possible to use.

  Such a composite fiber can be subjected to composite spinning by a conventional melt spinning method using a conventionally known spinning device or drawing device. That is, the modified EVOH and the thermoplastic resin are melted by separate extruders, then each molten polymer stream is guided to the spinning head, measured by a gear pump, and discharged from a composite spinning nozzle in a desired composite form. Accordingly, a composite fiber can be produced by performing a drawing process or the like and then winding it.

  The melting temperature at the time of spinning is appropriately adjusted depending on the melting point of the modified EVOH and the like, but is usually preferably about 150 to 300 ° C. The yarn discharged from the spinning nozzle is wound at a high speed without being stretched, or is stretched as necessary. The stretching operation is usually performed at a stretch ratio of 0.55 to 0.9 times the breaking elongation (HDmax) at a temperature equal to or higher than the glass transition point. If the draw ratio is less than 0.55 times the breaking elongation, it is difficult to stably obtain a fiber having sufficient strength, and if it exceeds 0.9 times the breaking elongation, it becomes easy to break the yarn.

  Stretching may be performed after winding and then stretching after being discharged from the composite spinning nozzle, or may be performed subsequent to stretching, and any may be used in the present invention. The stretching operation is usually performed by hot stretching, and may be performed using any of hot air, a hot plate, a hot roller, a water bath, and the like. Further, the take-up speed differs depending on whether the take-up process is performed after winding, the spin-drawing is performed in one step of direct spinning drawing, and the winding is performed as it is at a high speed without drawing. Taking up in the range of / min to 6000 m /. If it is less than 500 m /, productivity will be inferior, and if it is very high speed exceeding 6000 m / min, fiber breakage tends to occur. Further, the fiber cross-sectional shape of the present invention is not particularly limited, and can be made into a perfect circle, a hollow shape, or an irregular cross-section depending on the shape of the nozzle using a normal melt spinning method. A perfect circle is preferable from the viewpoint of process passability in fiberization and weaving.

  The composite form in the composite fiber can be any form such as a core-sheath type, a sea-island type, a bonding type, or a mixed type thereof. In the case of the core-sheath type, either a two-layer core-sheath type or a multilayer core-sheath type having three or more layers may be used. In the case of the sea-island type, the shape, number, and dispersion state of the islands can be arbitrarily selected, and part of the islands may be exposed on the fiber surface. Furthermore, in the case of the bonding type, in the fiber cross section perpendicular to the fiber length direction, the bonding surface may be in any state of a linear shape, an arc shape, or any other random curved shape, Even if the some bonding part is mutually parallel, it may become radial shape, and other arbitrary shapes may be sufficient as it.

  The cross-sectional shape of the conjugate fiber of the present invention may be any shape, and may be a shape suitable for the purpose, such as circular, irregular, hollow. In the case of an irregular cross section, for example, a flat shape, an oval shape, a square shape such as a triangle to an octagon, a C shape, a T shape, an H shape, a multileaf shape such as a 3-8 leaf shape, and an arbitrary shape such as a multi-branch shape can do. Furthermore, it is also possible to make a thick and thin form in which the thickness of the fiber changes along its length. Furthermore, the fibers of the present invention can contain optional additives such as fluorescent brighteners, stabilizers, flame retardants, and colorants that are commonly used in fiber-forming polymers, as necessary. Further, the fibers of the present invention can be used as appropriate for long fibers such as monofilaments, short fibers such as staples, multifilament yarns, spun yarns, and the like, and fibers of the present invention and natural fibers, semi-synthetic fibers, and other synthetic fibers. It can be applied as a blended yarn, blended yarn, or twisted yarn. The fiber of the present invention may be subjected to any treatment such as false twist crimping or entanglement treatment.

  The composite fiber of the present invention thus obtained is suitably used as a heat-sealing fiber because the modified EVOH has a low melting point. Moreover, since the crystallinity of the modified EVOH is low, it is also suitably used as a shrink fiber. Moreover, although it dyes | stains as needed, the composite fiber which uses the said modified | denatured EVOH of this invention as one component has favorable dyeability compared with unmodified | denatured EVOH.

  The conjugate fiber of the present invention can be used as a long fiber, or can be used as a short fiber by cutting appropriately. And since fabrics, such as a woven fabric, a knitted fabric, and a nonwoven fabric, can be manufactured, it uses suitably for various textiles. In particular, a fiber product containing the conjugate fiber of the present invention is useful for apparel because it has excellent hygroscopicity and good wearing feeling.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by these Examples.

[Production of modified EVOH]
Synthesis example 1
(1) Synthesis of modified EVAc In a 50 L pressure reaction vessel equipped with a jacket, a stirrer, a nitrogen inlet, an ethylene inlet and an initiator addition port, vinyl acetate (in formula (II), R ⁵ is a methyl group: 21 kg of VAc), 2.1 kg of methanol (hereinafter referred to as MeOH), 2-methylene-1,3-propanediol diacetate (in formula (III), R ¹ , R ² , R ³ and R ⁴ Was hydrogen atom, R ⁶ and R ⁷ were methyl group (hereinafter referred to as MPDAc) 1.1 kg, heated to 60 ° C., and then bubbled with nitrogen for 30 minutes to replace the inside of the reaction vessel with nitrogen. Next, ethylene was introduced so that the reaction vessel pressure (ethylene pressure) was 4.2 MPa. After adjusting the temperature in the reaction vessel to 60 ° C., 16.8 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (“V-65” manufactured by Wako Pure Chemical Industries, Ltd.) was used as an initiator. Polymerization was initiated by addition as a MeOH solution. During the polymerization, the ethylene pressure was maintained at 4.2 MPa and the polymerization temperature was maintained at 60 ° C. After 4.5 hours, the polymerization was stopped by cooling when the polymerization rate of VAc reached 34%. After the reaction vessel was opened to remove ethylene, nitrogen gas was bubbled to completely remove ethylene. Subsequently, unreacted VAc is removed under reduced pressure, and then MeOH is added to a modified ethylene-vinyl acetate copolymer into which a structural unit derived from MPDAc has been introduced by copolymerization (sometimes referred to as modified EVAc in this specification). A 20% by mass MeOH solution was added.

(2) Saponification of modified EVAc 5658 g of a 20 mass% MeOH solution of the modified EVAc obtained in (1) was charged into a 10 L reaction vessel equipped with a jacket, a stirrer, a nitrogen inlet, a reflux condenser and a solution addition port. The temperature was raised to 60 ° C. while blowing nitrogen into the solution, and a MeOH solution having a sodium hydroxide concentration of 2N was added at a rate of 14.7 mL / min for 2 hours. After completion of the addition of the sodium hydroxide MeOH solution, the saponification reaction was allowed to proceed by stirring for 2 hours while maintaining the system temperature at 60 ° C. Thereafter, 254 g of acetic acid was added to stop the saponification reaction. Thereafter, 3 L of ion exchange water was added while heating and stirring at 80 ° C., and MeOH was allowed to flow out of the reaction tank to precipitate modified EVOH. The modified EVOH precipitated by decantation was collected and pulverized with a mixer. The obtained modified EVOH powder was put into a 1 g / L acetic acid aqueous solution (bath ratio 20: 20 L of aqueous solution with respect to 1 kg of powder) and washed with stirring for 2 hours. This was drained, and further poured into a 1 g / L aqueous acetic acid solution (bath ratio 20), followed by stirring and washing for 2 hours. The liquid which had been drained was poured into ion-exchanged water (bath ratio 20), and the operation of stirring and washing for 2 hours to drain the liquid was repeated 3 times for purification. Next, the solution was dehydrated after being immersed in 10 L of an aqueous solution containing 0.5 g / L of acetic acid and 0.1 g / L of sodium acetate for 4 hours, and then dried at 60 ° C. for 16 hours to obtain a crude dried product of modified EVOH. Of 503 g.

(3) Production of modified EVOH hydrous pellets In a 3 L stirring tank equipped with a jacket, a stirrer, and a reflux condenser, 758 g of a modified EVOH crude product obtained by repeating (2) twice, 398 g of water and 739 g of MeOH were charged. The solution was heated to 85 ° C. and dissolved. This solution is extruded through a 4 mm diameter glass tube into a mixed solution of water / MeOH = 90/10 cooled to 5 ° C. to precipitate it into a strand, and this strand is cut into a pellet with a strand cutter to modify EVOH. Water-containing pellets were obtained. It was 55 mass% when the moisture content of the obtained modified EVOH hydrous pellet was measured with a halogen moisture meter “HR73” manufactured by Mettler.

(4) Manufacture of modified EVOH composition pellets 1577 g of the modified EVOH hydrous pellets obtained in (3) above were put into a 1 g / L acetic acid aqueous solution (bath ratio 20) and washed with stirring for 2 hours. This was drained, and further poured into a 1 g / L acetic acid aqueous solution (bath ratio 20), followed by stirring and washing for 2 hours. After draining, the acetic acid aqueous solution was renewed and the same operation was performed. Purified by repeating the operation of washing with acetic acid aqueous solution and removing the liquid into ion-exchanged water (bath ratio 20), stirring and washing for 2 hours, and removing the liquid three times. A modified EVOH hydrous pellet from which the residue was removed was obtained. The water-containing pellet is poured into an aqueous solution (bath ratio 20) having a sodium acetate concentration of 0.525 g / L, an acetic acid concentration of 0.8 g / L, and a phosphoric acid concentration of 0.007 g / L, and is immersed for 4 hours with periodic stirring. It was. This was drained and dried at 80 ° C. for 3 hours and at 105 ° C. for 16 hours to obtain modified EVOH composition pellets containing acetic acid, sodium salt and phosphate compound.

(5) Content of each structural unit in modified EVAc Content of ethylene unit in modified EVAc (a mol% in formula (IV)), content of structural unit derived from vinyl acetate (b mol in formula (IV) %) And MPDAc-derived structural unit content (c mol% in formula (IV)) were calculated as follows by measuring ¹ H-NMR of the modified EVAc before saponification.

First, a small amount of the MeOH solution of the modified EVAc obtained in (1) was sampled, and the modified EVAc was precipitated in ion exchange water. The precipitate was collected and dried at 60 ° C. under vacuum to obtain a dried modified EVAc. Next, the obtained dry product of modified EVAc was dissolved in dimethyl sulfoxide (DMSO) -d ₆ containing tetramethylsilane as an internal standard substance, and ¹ H-NMR of 500 MHz (manufactured by JEOL Ltd .: “GX-500”). )) And measured at 80 ° C.

FIG. 1 shows the ¹ H-NMR spectrum of the modified EVAc obtained in Synthesis Example 1. Each peak in the spectrum is assigned as follows.
0.6-1.0 ppm: methylene proton (4H) in the terminal site ethylene unit
1.0 to 1.85 ppm: methylene proton (4H) of intermediate site ethylene unit, main chain site methylene proton (2H) of structural unit derived from MPDAc, methylene proton of vinyl acetate unit (2H)
1.85-2.1 ppm: MPDAc-derived structural unit methyl proton (6H) and vinyl acetate unit methyl proton (3H)
3.7-4.1 ppm: side chain site methylene proton (4H) of structural unit derived from MPDAc
4.4-5.3 ppm: methine proton of vinyl acetate units (1H)

According to the above attribution, the integral value of 0.6 to 1.0 ppm is x, the integral value of 1.0 to 1.85 ppm is y, the integral value of 3.7 to 4.1 ppm is z, and 4.4 to 5. When the integrated value of 3 ppm is w, the content of ethylene units (a: mol%), the content of vinyl ester units (b: mol%) and the content of structural units derived from MPDAc (c: mol%) are Are calculated according to the following equations.
a = (2x + 2y−z−4w) / (2x + 2y + z + 4w) × 100
b = 8w / (2x + 2y + z + 4w) × 100
c = 2z / (2x + 2y + z + 4w) × 100
As a result of calculation by the above method, the ethylene unit content (a) was 32.0 mol%, the vinyl ester unit content (b) was 64.1 mol%, and the MPDAc-derived structural unit content (c) was It was 3.9 mol%. The values of a, b and c in the modified EVAc are the same as the values of a, b and c in the modified EVOH after saponification treatment.

(6) Saponification degree of modified EVOH The modified EVOH after saponification was similarly subjected to ¹ H-NMR measurement. The crude dried product of the modified EVOH obtained in the above (2), tetramethylsilane as an internal standard material was dissolved in dimethyl sulfoxide (DMSO) -d ₆ containing tetrafluoro acid (TFA) as an additive, the 500 MHz ¹ Measurement was performed at 80 ° C. using 1 H-NMR (manufactured by JEOL Ltd .: “GX-500”). FIG. 2 shows the ¹ H-NMR spectrum of the modified EVOH obtained in Synthesis Example 1. Since the peak intensity of 1.85 to 2.1 ppm is greatly reduced, in addition to the ester group contained in vinyl acetate, the ester group contained in the MPDAc-derived structural unit is also saponified into a hydroxyl group. It is clear. The degree of saponification was calculated from the peak intensity ratio of methyl protons (1.85 to 2.1 ppm) of vinyl acetate units and methine protons (3.15 to 4.15 ppm) of vinyl alcohol units. The degree of saponification of the modified EVOH was 99.9 mol% or more.

(7) Melting point of modified EVOH About the modified EVOH composition pellet obtained in (4) above, the temperature was raised from 30 ° C. to 215 ° C. at a rate of 10 ° C./minute according to JIS K7121, and then 100 ° C./minute. The sample was rapidly cooled to −35 ° C. and measured again at a rate of temperature increase of 10 ° C./min from −35 ° C. to 195 ° C. (differential scanning calorimeter (DSC) “RDC220 / SSC5200H” manufactured by Seiko Instruments Inc.). . Indium and lead were used for temperature calibration. The melting peak temperature (Tpm) was determined from the 2nd run chart according to the above JIS, and this was taken as the melting point of the modified EVOH. The melting point was 151 ° C.

(8) Sodium salt content and phosphate compound content in the modified EVOH composition 0.5 g of the modified EVOH composition pellets obtained in (4) above was placed in a Teflon (registered trademark) pressure vessel, and concentrated therein. Nitric acid (5 mL) was added and decomposed at room temperature for 30 minutes. After 30 minutes, the lid was covered, and decomposition was performed by heating at 150 ° C. for 10 minutes and then at 180 ° C. for 5 minutes with a wet decomposition apparatus (manufactured by Actac Co., Ltd .: “MWS-2”), and then cooled to room temperature. This treatment solution was transferred to a 50 mL volumetric flask (manufactured by TPX) and diluted with pure water. About this solution, the contained metal was analyzed with the ICP emission spectroscopic analyzer ("OPTIMA4300DV" manufactured by PerkinElmer Co., Ltd.), and the contents of sodium element and phosphorus element were determined. The sodium salt content was 150 ppm in terms of sodium element, and the phosphate compound content was 10 ppm in terms of phosphate radical.

In Examples, the evaluation of the composite fiber passing through the spinning process, strength, dyeability, adhesion, and texture was measured by the following methods.

(1) Spinning process passability Evaluation was made based on the occurrence of fluff breakage when spinning 100 kg.
○: Good with no fluff or yarn breakage.
(Triangle | delta): There is no thread breakage and generation | occurrence | production of fluff is recognized slightly.
X: Yarn breakage.

(2) Fiber strength Measured according to JIS L1013.

(3) Adhesiveness of each polymer of the composite fiber 24 to 36 filaments are twisted at 500 to 1000 T / M, the yarn is cut as it is, and the filament peeling state on the cut surface is increased by 500 times with an electron microscope. Magnified and observed. The 10 cut locations were evaluated according to the following criteria.
○: When the degree of peeling is less than 20%.
Δ: When the degree of peeling is 20% to 50%.
X: When the degree of peeling exceeds 50%.

(4) Dyeability The sensory evaluation was performed by 10 panelists on the color developability (clearness and gloss) of the fabric dyed under the following conditions. As a result, “very good” was 2 points, “excellent” was 1 point, and “inferior” was 0 point, and the overall points were divided into 3 stages.
○: The total score is 15 points or more.
(Triangle | delta): A total score is 6-14 points.
X: The total score is 6 or less.

Dyeing conditions:
Dye Sumifix Supra Brilliant Red 3BF 150% gran (manufactured by Sumitomo Chemical Co., Ltd.) 3% owf
Sodium sulfate (manufactured by Kanto Chemical Co., Inc.) 50 g / liter Sodium carbonate (manufactured by Kanto Chemical Co., Ltd.) 20 g / liter Bath ratio 1:30
60 ° C
60 minutes

Soaping conditions:
Amiradine (Madesei Chemical Co., Ltd.) 1 g / liter Bath ratio 1:50
60 ° C
20 minutes

(5) Moisture absorption rate The weight of the sample when reaching a saturated state under the conditions of a temperature of 20 ° C. and a humidity of 90% was determined from the following formula as the weight during moisture absorption.
Moisture Absorption Rate (%) = [(Sample Weight at Moisture Absorption−Sample Weight at Absolute Dryness) / Sample Weight at Absolute Dryness] × 100

(6) A shirt was created from a plain fabric to wear, and the comfort was sensory evaluated.
○: Refreshing comfort without sweating when sweating.
Δ: Slightly stuffy when sweating but recovers quickly.
X: Feels sultry when sweating and does not recover easily.

(7) Intrinsic viscosity of polyester [η] (d1 / g)
This is a value measured using an Ubbelohde viscometer in a constant temperature bath at 30 ° C. using an equal weight mixed solvent of phenol and tetrachloroethane.

Example 1
Polyester resin (polyethylene terephthalate; hereinafter abbreviated as PET) is used as one component constituting the composite fiber, and the modified EVOH obtained in Synthesis Example 1 is used as the other component, each using a separate extruder. The PET was melted at 290 ° C. and the modified EVOH was melted at 200 ° C., and the former and the latter were weighed with a gear pump so as to have a weight ratio of 50:50 and led to a spinning pack. A composite flow was formed so that the polymer flow had a concentric cross-sectional shape (core: PET, sheath: EVOH), and discharged from a nozzle having a hole diameter of 0.25 mm and a hole number of 24 at a spinneret temperature of 280 ° C., and 1000 m / Winded up at a speed of minutes. The obtained spinning yarn is stretched by a roller plate at a hot roller temperature of 80 ° C. and a hot plate temperature of 120 ° C. three times (corresponding to 0.7 times of HDmax), and the core / sheath ratio is 50/50 (weight ratio). A composite multifilament yarn of 83 dtex / 24 filament made of a bilayer concentric core-sheath composite fiber was obtained.

  The composite multifilament obtained was then used as warp and weft to produce a 1/1 plain fabric. The above-mentioned plain fabric plain fabric was dyed under the above-mentioned dyeing conditions using a normal liquid flow dyeing machine. Thereafter, a dry finish set was performed by a conventional method. Table 1 summarizes the evaluation results of the composite multifilament yarn passing through the spinning process, strength and adhesion, and the dyeability, moisture absorption rate and wearing feeling of the plain fabric obtained therefrom.

Example 2
In Synthesis Example 1 (1), polymerization was carried out in the same manner except that the ethylene pressure was 4.1 MPa and 1.5 kg of 2-methylene-1,3-propanediol was added instead of MPDAc. After 5 hours, the polymerization was stopped by cooling when the polymerization rate of VAc reached 28%. Using the modified EVOH thus obtained, subsequently, a multifilament yarn comprising a core-sheath composite fiber (core / sheath ratio = 50/50 (weight ratio)) of modified EVOH and PET in the same manner as in Example 1 and A plain fabric made of it was obtained. Various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 3
Polymerization was conducted in the same manner as in Synthesis Example 1 (1) except that the amount of initiator was 8.4 g and the amount of MPDAc charged was 0.5 kg. After 6 hours, when the polymerization rate of VAc reached 52%, the reaction was cooled to stop the polymerization. Using the modified EVOH thus obtained, subsequently, a multifilament yarn comprising a core-sheath composite fiber (core / sheath ratio = 50/50 (weight ratio)) of modified EVOH and PET in the same manner as in Example 1 and A plain fabric made of it was obtained. Various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 4
In Synthesis Example 1 (1), the amount of MeOH is 1.1 kg, the ethylene pressure is 3.8 MPa, the amount of MPDAc is 2.0 kg, and 16.8 g of initiator is added 5 hours after the start of polymerization. Polymerization was carried out in the same manner except that. After 10 hours, when the polymerization rate of VAc reached 9%, it was cooled and the polymerization was stopped. Using the modified EVOH thus obtained, subsequently, a multifilament yarn comprising a core-sheath composite fiber (core / sheath ratio = 50/50 (weight ratio)) of modified EVOH and PET in the same manner as in Example 1 and A plain fabric made of it was obtained. Various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 5
In Example 1 (1), the same procedure was performed except that the amount of MeOH was 1.1 kg, the amount of initiator was 16.8 g, the ethylene pressure was 6.0 MPa, and the charge amount of MPDAc was 1.1 kg. Polymerization was carried out by the method. After 4 hours, the polymerization was stopped by cooling when the polymerization rate of VAc reached 22%. Using the modified EVOH thus obtained, subsequently, a multifilament yarn comprising a core-sheath composite fiber (core / sheath ratio = 50/50 (weight ratio)) of modified EVOH and PET in the same manner as in Example 1 and A plain fabric made of it was obtained. Various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1
Polymerization was conducted in the same manner as in Synthesis Example 1 (1) except that the amount of MeOH was 6.3 kg, the amount of initiator was 4.2 g, the ethylene pressure was 3.7 MPa, and MPDAc was not charged. Unmodified EVAc was obtained. After 4 hours, when the polymerization rate of VAc reached 44%, the reaction was cooled to stop the polymerization. Using the unmodified EVOH thus obtained, subsequently, a multifilament yarn composed of a composite fiber of unmodified EVOH and PET and a plain fabric composed thereof were obtained in the same manner as in Example 1. Various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2
Polymerization was carried out in the same manner as in Synthesis Example 1 (1) except that the amount of MeOH was 4.2 kg, the amount of initiator was 4.2 g, the ethylene pressure was 5.3 MPa, and MPDAc was not added. And unmodified EVAc was obtained. After 3 hours, the polymerization was stopped by cooling when the polymerization rate of VAc reached 29.3%. Using the unmodified EVOH thus obtained, subsequently, a multifilament composed of a core-sheath type composite fiber (core / sheath ratio = 50/50 (weight ratio)) of unmodified EVOH and PET in the same manner as in Example 1. Yarn and a plain fabric made of it were obtained. Various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3
Using MeOH as a polymerization solvent and AIBN (azobisisobutyronitrile) as a polymerization initiator, ethylene, vinyl acetate and sodium 2-acrylamido-2-methylpropanesulfonate (hereinafter referred to as “60 ° C.” under pressure) , Abbreviated as AMPS) to produce an AMPS / ethylene / vinyl acetate copolymer having an AMPS content of 0.2 mol% and an ethylene content of 44 mol%. Next, this AMPS / ethylene / vinyl acetate copolymer was saponified in a caustic soda-containing MeOH solution, and then repeatedly washed with a large excess of pure water to which a small amount of acetic acid was added. Washing was repeated with excess pure water. Thereafter, water was separated from the copolymer by a dehydrator and then sufficiently dried by vacuum drying at a temperature of 100 ° C. or lower. The obtained AMPS / ethylene / vinyl alcohol copolymer (modified Et / VA copolymer) had a saponification degree of 99.5 mol% and a melt index (190 ° C. under a load of 2160 g) of 2 g / 10 min. Met. Using the modified Et / VA copolymer having a structural unit different from the modified EVOH of the present invention thus obtained, the modified Et / VA copolymer and PET were subsequently used in the same manner as in Example 1. A multifilament yarn comprising a core-sheath type composite fiber (core / sheath ratio = 50/50 (weight ratio)) and a plain fabric comprising the same were obtained. Various evaluations were performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 4
Modified EVAc was synthesized in the same manner as in Example 1 to obtain an EVAc MeOH solution. Subsequently, saponification treatment was performed using a MeOH solution of sodium hydroxide so that the saponification degree was less than 90 mol%. The saponification degree of the modified EVOH thus obtained was 87.0 mol%. The saponification degree of the modified EVOH thus obtained was 87.0 mol%. Using the modified EVOH thus obtained, an attempt was made to produce a multifilament yarn comprising a composite fiber of modified EVOH and PET in the same manner as in Example 1, but a gelled product was produced during spinning, and the filter of the spinning pack Clogging occurred and spinning was impossible.

  As shown in Table 1, the multifilament yarn described in Examples 1 to 5 composed of a composite fiber containing the modified EVOH of the present invention as one component exhibits good spinning process passability, and also has a fiber strength and PET. Excellent adhesion. This is because the modified EVOH has excellent stretchability and high adhesiveness / adhesion with PET. The modified EVOH was excellent in dyeability of the plain woven fabrics obtained in Examples 1 to 5 because the dye adsorbability was increased by introducing the structural unit (I). Furthermore, since the modified EVOH of the present invention increases the hygroscopicity due to the introduction of the structural unit (I), it also has a good comfort in the wear feeling of clothing. On the other hand, comparative examples using a modified EVOH having a structural unit different from that of unmodified EVOH or the modified EVOH of the present invention or having a low degree of saponification include spinning process passability, fiber strength, adhesion to PET, plain fabric It was inferior in the dyeability at the time of making, hygroscopicity, and the wearing feeling of clothing.

The present invention is a composite fiber made of modified EVOH, which retains a good texture similar to natural fibers that are soft and bulky, and retains moisture absorption and water absorption while being dyeable to reactive dyes. . Furthermore, the textiles manufactured from this composite fiber are included.
The composite fibers of the present invention include multifilament yarns, spun yarns, woven and knitted fabrics, non-woven fabrics, paper, artificial leather, filling materials, natural fibers, semi-synthetic fibers, and mixed yarns and blends with other synthetic fibers. Included are various finished products such as yarn, intertwisted yarn, processed yarn such as entangled yarn and crimped yarn, union woven fabric, union knitted fabric, fiber laminate, and clothing, living materials, industrial materials, medical supplies composed of these To do.

Claims (5)

Each monomer that is represented by the following formula (I) is a copolymer obtained by random copolymerization, a relative total monomer units, the content of b and c (mol%) of the following formulas (1) to A modified ethylene-vinyl alcohol copolymer satisfying (3) and having a saponification degree (DS) defined by the following formula (4) of 90 mol% or more as one component, A composite fiber comprising a thermoplastic resin other than coalesced as another component.

[In Formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the alkyl group contains a hydroxyl group, an alkoxy group or a halogen atom. But you can. X, Y and Z each independently represent a hydrogen atom, a formyl group or an alkanoyl group having 2 to 10 carbon atoms. ]
18 ≦ a ≦ 55 (1)
0.01 ≦ c ≦ 20 (2)
[100− (a + c)] × 0.9 ≦ b ≦ [100− (a + c)] (3)
DS = [(total number of moles of hydrogen atoms among X, Y and Z) / (total number of moles of X, Y and Z)] × 100 (4)   A composite fiber comprising the modified ethylene-vinyl alcohol copolymer according to claim 1 as a component, wherein the thermoplastic resin is polyester. R ¹ , R ² , R ³ and R ⁴ are hydrogen atoms. A composite fiber comprising the modified ethylene-vinyl alcohol copolymer according to any one of claims 1 and 2 as one component.   X, Y, and Z are a hydrogen atom or an acetyl group each independently, The composite fiber formed by using the modified ethylene-vinyl alcohol copolymer of any one of Claims 1-3 as one component.   A fiber product including a composite fiber comprising the modified ethylene-vinyl alcohol copolymer according to any one of claims 1 to 4 as one component.