JP2001248016A - Thermoplastic polyvinyl alcohol fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melt-spun fiber which contains water-soluble polyvinyl alcohol as at least one component, and to provide a fiber structure using the same. SOLUTION: This thermoplastic polyvinyl alcohol fiber obtained by melt- spinning polyvinyl alcohol having a 1,2-glycol bond content of 1.8 to 3.5 mol.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber comprising thermoplastic polyvinyl alcohol having at least one component having excellent water solubility and biodegradability, and a melt spinning method thereof. In addition, the present invention relates to a fiber structure such as a yarn, a woven fabric, a knitted fabric, a nonwoven fabric or the like containing the fiber and a fiber product obtained by treating the fiber structure with water.

[0002]

2. Description of the Related Art Conventionally, polyvinyl alcohol (hereinafter referred to as P
The water-soluble fibers (which may be abbreviated as VA) include: 1) wet spinning or dry-wet spinning fibers in which both the stock solution solvent and the solidification bath are aqueous; and 2) dry spinning in which the stock solution is aqueous. Fibers obtained by a wet spinning or dry-wet spinning (gel spinning) method in which both a stock solution solvent and a solidification bath are non-aqueous solvents are known.

[0003] These water-soluble PVA fibers are used as staples or shortcut fibers in dry nonwoven fabrics, spun yarns,
It is used in the papermaking field and the like, and is used as a multifilament in textiles and knits. In particular, shortcut fibers soluble in hot water at 80 ° C. to 90 ° C. occupy an important position in the papermaking industry as fibrous binders, and multifilaments are also often used as base fabrics for chemical lace. In recent years, environmental issues have attracted attention as eco-friendly biodegradable fibers.

However, in general, in these spinning methods, it is difficult to spin at a high speed of, for example, more than 500 m / min. As compared with the melt spinning method, various restrictions were imposed on the point that equipment for recovering various solvents used in the method was required, and it was undeniable that special consideration was required.

[0005] Examples of PVA fiberized by melt spinning are disclosed in JP-A-50-152062 and JP-A-50-1.
No. 52063 and Japanese Patent Application Laid-Open No. Sho 63-105112. However, the above-described conventional techniques have problems such as poor water solubility of PVA and breakage of single yarns in a fiberizing step.
Fibers that have both good water solubility and process stability in fiberization have not been able to be produced.

On the other hand, non-woven fabric structures are often used for disposable fiber products, and non-woven fabrics made of PVA fibers have been proposed. Some are used to the extent that they collapse. However, most of the water-soluble PVA non-woven fabrics proposed so far use PVA fibers obtained by a wet method or a dry-wet method. JP-A-5-34
No. 5013 proposes a PVA nonwoven fabric by a melt spinning method in part, but does not specifically explain anything, and moreover, satisfies all requirements such as process stability, water solubility, and water dissolvability. There is no description or suggestion as to what kind of PVA should be used for this purpose.

To solve the above-mentioned problems of the conventional water-soluble PVA fiber such as processability and water solubility, the present inventors have proposed a specific thermoplastic polyvinyl alcohol fiber, a method for producing the same, and a specific thermoplastic polyvinyl alcohol fiber. Alcohol non-woven fabric was proposed (Japanese Patent Application No. 10-357120).
The thermoplastic polyvinyl alcohol fiber obtained by the proposal can be produced by a conventional wet method, dry-wet method, dry method, the limit of productivity in the solvent spinning method, the limitation of the fiber cross-sectional shape, the installation of the recovery equipment, the water-soluble polyvinyl alcohol fiber A fiber containing at least one component of alcohol can be stably provided by a melt spinning method, and a water-soluble fiber produced from PVA fiber obtained by a conventional wet method, dry-wet method, dry method, and solvent spinning method. Alternatively, a nonwoven fabric having excellent water dissolvability can be provided with stable processability by a melt spinning method. However, higher water solubility and biodegradability are required for some applications.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems such as the processability and water solubility of the conventional water-soluble PVA fiber, and to improve the water-solubility and biodegradability. An object of the present invention is to provide a PVA fiber obtained by a melt spinning method and a fiber structure containing the same.

[0009]

That is, the present invention provides:
A thermoplastic polyvinyl alcohol fiber containing at least one component of polyvinyl alcohol having a content of 2-glycol bonds of 1.8 to 3.5 mol%. Also,
The present invention is a method for producing a fiber product, comprising a fiber structure containing the thermoplastic polyvinyl alcohol fiber as at least one component, treating the fiber structure with water, and dissolving and removing the polyvinyl alcohol. .

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION PVA used in the present invention has biodegradability, and is decomposed into water and carbon dioxide when treated with activated sludge or buried in soil. When PVA is continuously treated with activated sludge in the form of an aqueous solution, it is almost completely decomposed in 2 days to 1 month. 1,2 of PVA in the present invention
-The content of the glycol bond is 1.8 to 3.5 mol%, preferably 1.9 to 3.2 mol%, and 2.0 to 3.0 mol%.
Molar% is more preferred. When the content of the 1,2-glycol bond is less than 1.8 mol%, the effect on water solubility and biodegradability is not sufficient, and the spinnability may decrease due to an increase in melt viscosity. . On the other hand, when the content of the 1,2-glycol bond exceeds 3.5 mol%, the thermal stability of PVA may be deteriorated, and the melt spinnability may be reduced.

The method for introducing a 1,2-glycol bond into PVA is not particularly limited, and a known method can be used. As an example, vinylene carbonate is used in the above 1,2
-A method of copolymerizing so as to have a glycol bond amount, and a method of polymerizing at a polymerization temperature higher than usual conditions, for example, 75 to 200 ° C. In the latter case,
The polymerization temperature is preferably from 90 to 190 ° C.
It is particularly preferred that the temperature be 0 to 180 ° C.

The content of 1,2-glycol bonds in PVA can be determined from NMR peaks. First, after saponifying PVA to a saponification degree of 99.9 mol% or more,
After thoroughly washing with methanol and then drying at 90 ° C. under reduced pressure for 2 days, PVA was dissolved in DMSO-D6, and a few drops of trifluoroacetic acid was added thereto.
It measures at 80 degreeC using MR (JEOL GX-500). The peak derived from methine in the vinyl alcohol unit is 3.
2 to 4.0 ppm (integral value A), a peak derived from one methine of 1,2-glycol bond is attributed to 3.25 ppm (integral value B), and the 1,2-glycol bond content is calculated by the following formula. it can. Here, Δ represents the amount of modification (mol%). 1,2-glycol bond content (mol%) = 100 B /
{100A / (100-Δ)}

The polyvinyl alcohol used in the present invention is obtained by using a heat-meltable PVA resin and saponifying a vinyl ester polymer. Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, and vinyl pivalate. Vinyl acetate is often used industrially. PVA may contain α-olefin units. They have 4 or less carbon atoms, for example, ethylene, propylene,
1-butene, isobutene and the like, but strength physical properties,
In view of the form stability, ethylene is more preferred. α
The content of olefin units is from 1 to 20 mol%,
When the content is more than 20 mol%, the solubility of the modified PVA in water decreases.

The PVA used in the present invention may contain a monomer unit other than a vinyl alcohol unit, a vinyl ester unit and an α-olefin unit as long as the effects of the present invention are not impaired. Examples of such a unit include unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (phthalic anhydride), maleic anhydride (anhydride), and itaconic acid, or salts thereof, or alkyl esters having 1 to 18 carbon atoms. , Acrylamide, N having 1 to 18 carbon atoms
Acrylamides such as -alkylacrylamide, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or a salt thereof, acrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, methacrylamide, N- having 1 to 18 carbon atoms; Methacrylamides such as alkyl methacrylamide, N, N-dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or a salt thereof, methacrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, N-vinylpyrrolidone, N- N-vinylamides such as vinylformamide and N-vinylacetamide; vinyl cyanides such as acrylonitrile and methacrylonitrile; methyl vinyl ether, ethyl vinyl ether; Ether, i-propyl vinyl ether, vinyl ethers such as n-butyl vinyl ether, allyl acetate, propyl allyl ether, butyl allyl ether, allyl ethers such as hexyl allyl ether, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, Vinyl halides such as vinyl bromide, vinyl silanes such as trimethoxyvinyl silane, monomers having an oxyalkylene group, isopropenyl acetate, 3-buten-1-ol, 4-penten-1-ol, 5-hexene Hydroxy-containing α such as -1-ol, 7-octen-1-ol, 9-decen-1-ol, 3-methyl-3-buten-1-ol, etc.
A monomer having a carboxyl group derived from olefins, fumaric acid, maleic acid, itaconic acid, maleic anhydride, phthalic anhydride, trimellitic anhydride or itaconic acid, ethylenesulfonic acid, allylsulfonic acid, methallyl Monomers having a sulfonic acid group derived from sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, etc., vinyloxyethyltrimethylammonium chloride, vinyloxybutyltrimethylammonium chloride, vinyloxyethyldimethylamine, vinyloxymethyldiethylamine , N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylamidodimethylamine, allyltrimethylammonium chloride, methallyltrime Le ammonium chloride, dimethyl allyl amine include monomers having a cationic group derived from the allyl ethyl amine. Among these monomers, N-vinylpyrrolidone, N-vinylpyrrolidone, N-vinylpyrrolidone,
N-vinylamides such as vinyl formamide and N-vinylacetamide, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether and n-butyl vinyl ether, allyl acetate, propyl allyl ether and butyl allyl ether , Allyl ethers such as hexyl allyl ether, monomers having an oxyalkylene group, 3-buten-1-ol, 4-pentene-1-
All, 5-hexen-1-ol, 7-octene-1
-Ol, 9-decene-1-ol, 3-methyl-3-
Monomers derived from hydroxy group-containing α-olefins such as buten-1-ol are preferred. Further, when the α-olefin is ethylene, the fiber properties are increased, so that the ethylene unit particularly has 2 to 15 mol%,
It is more preferable to use modified PVA in which 4 to 13 mol% is introduced.

As the polymerization method of the vinyl ester polymer, known methods such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method are exemplified. Among them, a bulk polymerization method or a solution polymerization method in which polymerization is performed without a solvent or in a solvent such as an alcohol is usually employed. Examples of the alcohol used as a solvent during the solution polymerization include lower alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol. As the initiator used for the polymerization, for example,
An azo initiator or a peroxide initiator such as α, α'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile, benzoyl peroxide, n-propylperoxycarbonate, etc. Known initiators such as, for example, those having a half-life of at least 1 hour at 100 ° C. The polymerization may be performed in any form as long as the pressure in the polymerization machine can be maintained at a pressure higher than the atmospheric pressure. A known stirring device may be used, and the polymerization system may be any of batch polymerization, semi-continuous polymerization, and continuous polymerization.

The vinyl ester polymer is saponified by a known method. For example, it is saponified while being dissolved in alcohol. Examples of the alcohol used for the saponification reaction include lower alcohols such as methyl alcohol and ethyl alcohol, and methyl alcohol is particularly preferably used. Alcohol used in the saponification reaction includes
If it is 40% by mass or less, it may contain a solvent such as acetone, methyl acetate, ethyl acetate, and benzene. As a catalyst used for the saponification reaction, an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide, an alkali catalyst such as sodium methylate, or an acid catalyst such as a mineral acid is used. The temperature of the saponification reaction is not particularly limited, but is preferably in the range of 20 to 60 ° C. When a gel-like product precipitates as the saponification reaction proceeds, the PVA polymer of the present invention is obtained by pulverizing the product at that time, washing and drying.

The viscosity-average degree of polymerization of the PVA produced as described above (hereinafter simply referred to as the degree of polymerization) is 200 to 200.
It is preferably 500, more preferably 230 to 470, and particularly preferably 250 to 450. Polymerization degree is 20
If it is less than 0, sufficient spinnability cannot be obtained during spinning, and fiberization may not be possible. If the degree of polymerization exceeds 500, the melt viscosity may be too high to discharge the polymer from the spinning nozzle.

The degree of polymerization (P) of PVA is determined according to JIS-K67.
26 is measured. That is, after PVA is re-saponified and purified, the intrinsic viscosity [η] measured in water at 30 ° C. is determined by the following equation. P = ([η] × 10 ³ /8.29) ^{(1 / 0.62) When the} degree of polymerization is in the above range, the object of the present invention can be more suitably achieved.

The degree of saponification of PVA is preferably from 90 to 99.99 mol%, more preferably from 93 to 99.98 mol%, even more preferably from 94 to 99.97 mol%, and preferably from 96 to 99.96 mol%. % Is particularly preferred. When the saponification degree is low, it is difficult to perform satisfactory melt spinning due to poor thermal stability and thermal decomposition and gelation of PVA, and the water solubility of PVA decreases depending on the type of a copolymerized monomer described below, There are cases where the object of the present invention cannot be achieved. On the other hand, PVA having a degree of saponification of more than 99.99 mol% cannot be produced stably, and stable fiberization may not be achieved.

In the present invention, a stabilizer such as a copper compound, a coloring agent, an ultraviolet absorber, a light stabilizer, an antioxidant, and an antistatic agent may be added to PVA, if necessary, as long as the object and effects are not impaired. , Flame retardants, plasticizers, lubricants, and crystallization rate retarders can be added during the polymerization reaction or in a subsequent step. In particular, organic stabilizers such as hindered phenol as heat stabilizers, copper halide compounds such as copper iodide,
It is preferable to add an alkali metal halide compound such as potassium iodide because the melt retention stability during fiberization is improved.

If necessary, the average particle size is 0.01 μm.
Fine particles having a particle size of m or more and 5 μm or less can be added at 0.05% by mass or more and 10% by mass or less during the polymerization reaction or in a subsequent step. The type of the fine particles is not particularly limited, and for example, inert fine particles such as silica, alumina, titanium oxide, calcium carbonate, and barium sulfate can be added. These may be used alone or in combination of two or more. . In particular, inorganic fine particles having an average particle diameter of 0.02 μm or more and 1 μm or less are preferable, and spinnability and stretchability are improved.

The thermoplastic polyvinyl alcohol fiber of the present invention includes not only the above-mentioned fiber composed of PVA alone, but also a composite spun fiber comprising the PVA as a component and having a melting point of 270 ° C. or less with another thermoplastic polymer. It also includes mixed spun fibers. The composite form of the composite fiber is not particularly limited, and can be appropriately set, such as a core-sheath type, a sea-island type, a side-by-side type, a multilayer laminated type, a radial split type, or a combination thereof. For example, if the composite fiber has PVA as a sea component and another thermoplastic polymer as an island component, the sea component PV
By removing A, ultrafine fibers can be formed. If the composite fiber has PVA as a core component and another thermoplastic polymer as a sheath component, a hollow fiber can be obtained by removing the PVA later. Furthermore, PV
A is used as a sheath component, and a composite fiber containing another thermoplastic polymer as a core component is made into a fabric, and then treated with water to remove the sheath component, thereby improving the texture of the fabric, or improving the composite properties. It is also possible to leave the sheath component of the fiber positively and act as a binder fiber. When making a composite fiber,
As a polymer combined with PVA, the melting point is 270.
° C. or lower is preferably a thermoplastic polymer, for example, for example, polyethylene terephthalate, polybutylene terephthalate, aromatic polyesters such as polyhexamethylene terephthalate and copolymers thereof, polylactic acid,
Polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvalerate copolymer,
Aliphatic polyesters such as polycaprolactone and copolymers thereof, nylon 6, nylon 66, nylon 10,
Aliphatic polyamides such as nylon 12, nylon 6-12 and copolymers thereof, polypropylene, polyethylene,
Polyolefins such as polybutene and polymethylpentene, and copolymers thereof;
At least one selected from the group consisting of modified polyvinyl alcohol, polystyrene, polydiene, chlorine, polyolefin, polyester, polyurethane, and polyamide elastomers containing mol% can be used.

From the viewpoint that composite spinning with the PVA used in the present invention is easy, polybutylene terephthalate, ethylene terephthalate copolymer, polylactic acid, nylon 6,
Nylon 6-12, polypropylene, 2 ethylene units
Modified polyvinyl alcohol containing 5 mol% to 70 mol% is preferred.

When the above-mentioned polyester copolymer is used, the copolymerization components include, for example, isophthalic acid, naphthalene-2,6-dicarboxylic acid, phthalic acid,
α, β- (4-carboxyphenoxy) ethane, 4,
Aromatic dicarboxylic acids such as 4′-dicarboxydiphenyl, 5-sodium sulfoisophthalic acid, adipic acid,
Aliphatic dicarboxylic acids such as sebacic acid, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,
Diol compounds such as 4-dimethanol, polyethylene glycol, polytrimethylene glycol, polypropylene glycol, and polytetramethylene glycol can be used, and the copolymerization ratio is preferably 80 mol% or less.

In producing a fiber made of an aliphatic polyester by removing the other component from a conjugate fiber containing an aliphatic polyester such as polylactic acid as one component, the other component is extracted with a chemical other than water. Then, the aliphatic polyester fiber is deteriorated and decomposed. Therefore, in producing a conjugate fiber containing such a polyester as one component, it is effective to use the PVA shown in the present invention as the other component.
Further, in the present invention, when an aliphatic polyester such as polylactic acid is used as the thermoplastic polymer having a melting point of 270 ° C. or less, the polylactic acid itself has biodegradability, and the polyvinyl alcohol component also has biodegradability, The entire fiber can be made biodegradable.

In the production of the fiber of the present invention, a known melt spinning apparatus can be used for both single spinning and composite spinning. That is, in the case of single spinning, it is obtained by melt-kneading PVA pellets 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 case of composite spinning, PVA and another thermoplastic polymer may be melt-kneaded by different extruders, and then discharged from the same spinning nozzle. As the cross-sectional shape of the fiber, not only the round cross-section but also various types such as C-shaped, 3-lobe, T-shaped, 4-lobe, 5-lobe, 6-lobe, 7-lobe, 8-lobe, cross-shaped, etc. Is possible.

In the present invention, in order to improve spinnability, spinning is preferably performed by adding a plasticizer to PVA. The plasticizer is not particularly limited as long as it is a compound capable of lowering the glass transition point and melt viscosity of PVA. For example, water, ethylene glycol and its oligomer, polyethylene glycol, propylene glycol and its oligomer, butylene glycol and its oligomer , Polyglycerol derivatives and glycerin to ethylene oxide, glycerin derivatives to which alkylene oxides such as propylene oxide are added, sorbitol to ethylene oxide, derivatives to which alkylene oxides such as propylene oxide are added, polyhydric alcohols such as pentaerythritol and derivatives thereof, PO / EO random copolymers and the like can be mentioned. These plasticizers
1 to 30% by mass, preferably 2 to 20% by mass of P
It is preferable to mix it with VA. And, in order to obtain good plasticity and spinnability, thermal decomposition hardly occurs in the fiberization step, and an alkylene oxide adduct of sorbitol,
Polyglycerin alkyl monocarboxylate, PO
/ EO plasticizer such as random copolymer is blended in an amount of 1 to 30% by mass, preferably 2 to 20% by mass.
Compounds with molar addition are preferred.

The yarn discharged from the spinning nozzle is wound up at high speed without stretching or stretched as required.
The stretching 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.

The spun fiber is usually provided with an oil agent, but the PVA constituting the fiber of the present invention is water-soluble,
Since the fiber has high hygroscopicity, it is preferable to provide a straight oil agent containing no water.

When the fiber of the present invention is a single fiber composed of 100% PVA, the fusing temperature of the fiber in water varies depending on the use, but it is preferable to melt at a low temperature from the viewpoint of economy. The fusing temperature is 2mg / dtex for the fiber.
Is suspended under water with a load of, and the temperature at which the fibers melt when the water temperature is raised. In the present invention, the fact that a single fiber composed of 100% PVA is “water-soluble” means that the fiber is cut off at a predetermined temperature when measured by the above method, regardless of the length of time until dissolution. . By changing the type of PVA and the manufacturing conditions of the fiber, it is possible to obtain a fiber containing at least one component of PVA having a fusing temperature of about 10 ° C. to 100 ° C. in the present invention. Fibers containing natural PVA as a component may easily absorb moisture or have low fiber strength. To balance all properties such as handleability, practicality, and water solubility, it is necessary to melt the fibers at 40 ° C or higher. Preferably, the fibers have a temperature.

The dissolution treatment temperature may be appropriately adjusted according to the water solubility of PVA and the intended use. The higher the treatment temperature, the shorter the treatment time. 50 ° C when dissolving using hot water
The treatment is preferably carried out as described above, more preferably at least 60 ° C, particularly preferably at least 70 ° C, most preferably at least 80 ° C. The melting treatment of the melt-spun fiber made of PVA may involve decomposition of the fiber. The aqueous solution is usually soft water, but may be an alkaline aqueous solution, an acidic aqueous solution, or the like, or may contain a surfactant or a penetrant.

The PVA fiber obtained as described above is
A fibrous structure such as a thread, a woven fabric, a knitted fabric, or a nonwoven fabric can be used alone or in combination with another water-insoluble fiber or a fiber that is less water-soluble than the PVA. In this case, PVA
The fiber may be a composite fiber composed of PVA and another thermoplastic polymer or a mixed spun fiber. The mode of use of the PVA fiber of the present invention is not particularly limited because it can be changed according to the application. For example, PVA fiber may be used by leaving it positively as a binder component in a fiber structure. On the other hand, yarns such as structural processing yarns, blended yarns, spun yarns, etc. are made from fibers containing at least one component of PVA and water-insoluble fibers. By treating and dissolving and removing the PVA component to form a space in the final product, it is possible to impart functionalities such as bulkiness, soft touch, elasticity, and heat retention and to improve the feeling. The latter type of functionality, for example,
It can be achieved by treatment of polyester fiber or polystyrene as a component with an aqueous alkali solution or an organic solvent, but the present invention has a great feature in that such functionality can be imparted by harmless water treatment. It has.

Modified polyvinyl alcohol (modified PVA)
When a non-woven fabric is manufactured from a fiber having at least one component, even if the non-woven fabric is formed by a dry method or a wet method (paper) using the fiber obtained by the above-described fiber manufacturing method, a spun bond method or the like is used. A nonwoven fabric may be directly formed after melt spinning.

The fibers of the present invention containing at least one specific PVA as described above, and fiber structures containing the fibers, such as yarns, knitted fabrics and nonwoven fabrics, are, for example, binder fibers for papermaking and binder fibers for nonwoven fabrics. , Staples for dry nonwoven fabrics, staples for spinning, multifilaments for woven and knitted fabrics (structured yarns, mixed yarns), chemical lace base fabrics, hollow fabrics, sewing threads, water-soluble packaging materials, diaper liners, disposable diapers, sanitary products, incontinence Sanitary materials such as pads, surgical gowns, surgical tapes, masks, sheets, bandages, gauze, clean cotton, first-aid base fabrics, pulp base fabrics, wound dressings, and other medical-related products, wrapping materials, splicing tapes, and hot melts Sheets (including temporary fixing sheets), interlining, vegetation sheets, agricultural covering materials, root-wrapping sheets, water-soluble ropes, fishing Threads, cement reinforcements, rubber reinforcements, masking tapes, caps, filters, wiping cloths, polishing cloths, towels, towels, cosmetic puffs, cosmetic packs, aprons, gloves, table cloths, toilet seat covers, etc. It can be used for applications such as a breathable rewetting adhesive used as a back glue for covers, wallpapers, wallpapers, etc., and water-soluble toys.

[0035]

EXAMPLES Next, the present invention will be described specifically with reference to Examples.
The present invention is not limited to these examples. In the examples, parts and% relate to mass unless otherwise specified.

[Analysis method of PVA] The analysis method of PVA was in accordance with JIS-K6726 unless otherwise specified. The amount of modification was determined using a modified polyvinyl ester or modified PVA with a 500 MHz proton NMR (JEOL GX-
500) It was determined from measurement by an apparatus. The content of the alkali metal ion was determined by an atomic absorption method.

[Water solubility] The fusing temperature of the PVA fiber of the present invention in water is determined by applying a load of 2 mg / dtex to the fiber.
The fiber was immersed in water together with the scaled plate so that the immersion length of the fiber was about 10 cm, and the temperature at which the fiber melted when the temperature was raised from a water temperature of 20 ° C. at a rate of 1 ° C./min was examined.
Separately from this, the presence or absence of undissolved matter when stirred in water at 90 ° C. for 1 hour was visually observed.

[Fiber strength and elongation] JIS L1013
It measured according to.

[Spinnability] PVA is melt-kneaded using a melt extruder, the molten polymer stream is guided to the spinning head, weighed with a gear pump, and in the case of single spinning, the hole diameter is 0.25 mm.
In the case of composite spinning, a test was conducted for winding the yarn discharged from a nozzle having 24 holes each having a hole diameter of 0.4 mm at a speed of 800 m / min for 6 hours, and the spinning condition at that time was evaluated. A: Winding can be performed for 6 hours without breakage of single yarn. ：: There is one single yarn break in 6 hours, but it can be wound up as a multifilament for 6 hours. ○ to Δ: Two or more single yarn breaks occur in 6 hours, but can be wound as a multifilament for 6 hours. Δ: Single yarn breakage is remarkable, and about 5 as a multifilament
It can be wound up for only a minute. X: The single yarn breakage was remarkable, and no winding was possible.

Example 1 24.6 kg of vinyl acetate and 5.4 kg of methanol were charged into a 50 L pressure reactor equipped with a stirrer, a nitrogen inlet, an ethylene inlet, an initiator addition port and a delay solution addition port. After the temperature was raised, the inside of the system was replaced with nitrogen by bubbling nitrogen for 30 minutes. Next, the reaction tank pressure was 21.0 kg
/ Cm ² (2.1 × 10 ⁶ Pa). A 0.1 g / L solution in which 2,2′-azobis (N-butyl-2-methylpropionamide) was dissolved in methanol as an initiator was prepared, and nitrogen substitution was performed by bubbling with nitrogen gas. When the temperature inside the polymerization tank is 15
After the temperature was adjusted to 0 ° C., 190 ml of the above initiator solution was injected to start polymerization. During the polymerization, ethylene was introduced to maintain the reactor pressure at 21.0 kg / cm ² (2.1 × 10 ⁶ Pa), the polymerization temperature at 150 ° C., and 800 ° C. using the above initiator solution.
Polymerization was carried out by continuously adding 2,2′-azobis (N-butyl-2-methylpropionamide) at ml / hr. After 4 hours, when the polymerization rate reached 50%, the polymerization was stopped by cooling. After the reaction vessel was opened to remove ethylene, nitrogen gas was bubbled through to completely remove ethylene. Next, unreacted vinyl acetate monomer was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate. Methanol solution of polyvinyl acetate adjusted to a concentration of 35% by adding methanol to the obtained polyvinyl acetate solution 2
86 g (100 g of polyvinyl acetate in solution);
Saponification was carried out by adding an alkali solution (NaOH 10% methanol solution) having a molar ratio (MR) of 0.08 to the vinyl acetate unit in polyvinyl acetate. After about 2 minutes from the addition of the alkali, the gelled system was pulverized with a pulverizer and left at 40 ° C. for 1 hour to progress the saponification. Then, 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the completion of the neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration and washed at room temperature for 3 hours. After repeating the above washing operation three times, the PVA obtained by centrifugal drainage is left in a dryer at 70 ° C. for 2 days to dry PVA.
VA was obtained. When the above-mentioned analysis was performed on the obtained ethylene-modified PVA, the degree of polymerization was 450 and the degree of saponification was 9
7.7 mol%, ethylene modification amount 4 mol%, melting point 209
C. and 2.4 mol% of 1-2 glycol bond (Table 1).
reference).

[0041]

[Table 1]

The modified PVA obtained above was melt-kneaded at 240 ° C. using a melt extruder, and the molten polymer stream was guided to a spinning head, weighed with a gear pump, and measured for a pore diameter of 0.25 m.
m, and discharged from a nozzle having 24 holes, and wound up at a speed of 800 m / min for 6 hours. 1. The obtained spun yarn is heated at a hot roller temperature of 80 ° C and a hot plate temperature of 160 ° C.
Roller plate drawing was carried out 1 time (corresponding to HDmax × 0.7) to obtain a drawn yarn of 83 dtex / 24f. Table 2 shows the strength, elongation, water solubility and fusing temperature of the drawn yarn.

[0043]

[Table 2]

Next, a knitted fabric was prepared from the drawn yarn using a tubular knitting machine, but no fibrillation of fibers occurred in the process.

In addition, the PVA drawn filament obtained above, an undrawn filament yarn made of polyethylene terephthalate having an intrinsic viscosity of 0.68 and a breaking elongation of 162% [9
4dtex / 48f] and a drawing filament yarn [56dtex / 12f] with a breaking elongation of 32% made of polyethylene terephthalate having an intrinsic viscosity of 0.67, and interlaced at an overfeed rate of 5.5%. Stretching ratio 1.072 times, friction disk / yarn processing speed (D / Y) = 1.782, false twist speed 255 m /
Then, false twisting was performed under the condition of a first heater temperature of 180 ° C. to produce a polyester-based structured yarn. After giving a true twist of 800 turns / m to the polyester-based structured yarn obtained above using a double twister, this polyester-structured yarn is used as a weft, and a normal polyethylene terephthalate-structured yarn [150 dtex / 60f] is used. : Sheath yarn 94dtex / 48f, core yarn 56dtex / 12f]
Was given a real twist of 1800 T / M to give a warp yarn, thereby producing a 1/2 twill woven fabric. At this time, the mass ratio of weft: warp was 1: 1. The obtained greige was subjected to scouring-relaxation treatment using soda ash, and then preset at 190 ° C, and then treated in hot water at 95 ° C for 60 minutes,
All of the drawn PVA yarn was dissolved and removed. In addition, the wastewater from which PVA was dissolved and removed was collected and examined for biodegradability (Table 2).

The biodegradability of the PVA extract dissolved and removed was evaluated by the following method. [Biodegradability of extracted component] Activated sludge amount is 9mg to 30m
g of the activated sludge and 30 mg of the extracted component in the inorganic culture area according to JIS-K-6950 except that the
(The extract was dried and then weighed to make an aqueous solution), and a coulometer (Okura Electric OM3001A) was added.
(Type) and cultured at 25 ° C. for 28 days, and the amount of oxygen consumed for biodegradation was measured to determine the biodegradation rate after 28 days.

Further, the obtained woven fabric was washed with water, dried and dyed in the usual manner, and then subjected to final setting at a temperature of 170 ° C. without stretching the wrinkle without tension to obtain a woven fabric. The obtained woven fabric was light in weight, stretchable, and had good tension. When the cut surface of the woven fabric was observed with an electron microscope, it was observed that a high void structure was developed.

Example 2 In the fiberization of Example 1, a plasticizer in which 2 mol of ethylene oxide was added to 1 mol of sorbitol was added to the modified PVA so as to have a mixing ratio of 10% by mass.
When fibrillation was performed, the fibrillation processability was more stable than when no plasticizer was added, and the solubility in water was better than that without addition. In addition, a feature that the amount of the dissolved substance adhered to the dissolution treatment container was small was recognized.

Examples 3 to 5 In the same manner as in Example 1 except that the PVA shown in Table 1 was used in place of the PVA used in Example 1, and the fiber was formed at the spinning temperature shown in Table 2, the drawing of PVA was carried out. Yarn was obtained. Table 2 shows the spinnability and the strength, elongation, water solubility, fusing temperature, and biodegradability of the solution obtained from the drawn yarn.

Example 6 The spun yarn obtained in Example 1 was 2.06 times between the first and second rollers at 85 ° C. of the first roller, 160 ° C. of the second roller, and 30 ° C. of the third roller. (HDmax ×
(Corresponding to 0.72), and stretched and heat-treated so that a contraction of 3% occurs between the second roller and the third roller.
A 3dtex / 24f drawn yarn was obtained. Next, using the obtained PVA drawn yarn, a twisting of 250 T / m is performed to give a warp, and the weft is left as it is as a plain woven fabric (warp 120 / inch,
(Weft: 95 / inch) was prepared, this was used as a chemical lace base cloth, rayon yarn was used as the embroidery thread, and a tulle lace for inner use was selected for the design, and a chemical lace was prepared. Then, when the tulle was finished by treating with hot water at 98 ° C., the base fabric made of PVA fiber was completely dissolved,
The fine embroidery patterns were beautifully finished. The biodegradability of the PVA after dissolution was good and the decomposition rate was 97%.

Comparative Examples 1 and 2 The PVA shown in Table 1 was used in place of the PVA used in Example 1, and the fiber was drawn at the spinning temperature shown in Table 2 in the same manner as in Example 1 to extend the PVA. Yarn was obtained. However, in Comparative Example 1, the spinning temperature had to be increased due to the high viscosity, and it was considered that the spinning temperature was degraded and gelled, but the spinnability was not good. The film was stretched in the same manner as in Example 1, and 90
Dissolution treatment was performed in water at 1 ° C. for 1 hour, but some undissolved substances remained and did not completely dissolve. The biodegradability of the solution was also low. Table 2 shows spinnability and strength, elongation, water solubility, fusing temperature, and biodegradability of the obtained drawn yarn. Further, a twill fabric was produced in the same manner as in Example 1, and PV
Although a woven fabric was obtained by dissolving and removing the drawn A yarn, it is presumed that undissolved PVA remains. However, a part of the woven fabric had a hard part and was not usable.

In Comparative Example 2, since the thermal stability of PVA was poor, the PVA was thermally decomposed and gelled during spinning and could be wound up for only a very short time (about 5 minutes). The obtained raw yarn was stretched in the same manner as in Example 1 and subjected to a dissolving treatment in water at 90 ° C. for 1 hour. However, some undissolved substances remained due to gelation and did not completely dissolve. Table 2 shows spinnability and strength, elongation, water solubility, fusing temperature and biodegradability of the obtained drawn yarn.
Shown in A twill fabric was manufactured in the same manner as in Example 1, and
A woven fabric was obtained by dissolving and removing the VA drawn yarn, but as in Comparative Example 1, there was a hard part in the woven fabric, and it was not usable.

Example 7 The PVA used in Example 1 and the polylactic acid having a D-form content of 1% (melting point: 170 ° C.) were melted and kneaded with different extruders, and the modified PVA was placed on the sea side. Then, the polylactic acid was guided to a spinning pack at 235 ° C. so as to be on the island side.
Composite spinning was performed at 4 mmφ × 24 holes at a discharge rate of 24 g / min and wound at a spinning speed of 800 m / min to obtain a sea-island composite fiber having a sea-island composite ratio of 1: 1 and 16 islands. Next, the obtained spun yarn is 2.8 times (HDm) in a hot air oven at 150 ° C.
ax × 0.7) to obtain a conjugate fiber having a single fiber fineness of 4 dtex. Subsequently, a tubular knitted fabric was prepared using the composite fiber, immersed in hot water at 95 ° C. for 1 hour, and the PVA component was removed to obtain a knitted fabric made of polylactic acid fiber. The obtained knitted fabric had a good texture, and the fineness of the fiber obtained by unraveling the knitted fabric was a very fine fiber of about 0.17 dtex, and the physical properties were sufficient. The biodegradability of the wastewater obtained by dissolving and removing the PVA was investigated and the decomposition rate was 98%.

Comparative Example 3 A knitted fabric was prepared in the same manner as in Example 7 except that polyethylene (Mirason FL60: Mitsui Chemicals) was used instead of PVA used in Example 7. The knitted fabric was subjected to an extraction treatment using toluene at 90 ° C., but the knitted fabric obtained after the extraction was inferior in texture and poor in fiber properties. Further, the wastewater from which the polyethylene was dissolved and removed was collected and examined for biodegradability, but it was not substantially decomposed at a decomposition rate of 2%.

Comparative Example 4 In place of PVA used in Example 7, an intrinsic viscosity of 0.51 was used.
(Measured at 30 ° C. with a phenol / tetrachloroethane equal-mass mixed solvent) and spun at 270 ° C. using polyethylene terephthalate modified with 5 mol% of sulfoisophthalic acid and 4 mass% of polyethylene glycol. In the same manner, it was made into a fiber and knitted. The knitted fabric was subjected to an extraction treatment using 98 g of 40 g / L NaOH. By this extraction treatment, not only modified polyethylene terephthalate but also polylactic acid was dissolved and decomposed, and a knitted fabric of polylactic acid was not obtained.

Example 8 The drawn yarn (single fiber fineness: 4 dtex) obtained in Example 7 was crimped by a crimping machine and cut to 51 mm to obtain short fibers.
The short fibers were carded with a roller card and entangled with a needle punch to form a nonwoven fabric. 95 ℃
In hot water for 1 hour to remove the modified PVA to obtain a sheet made of polylactic acid. The obtained sheet had sufficient strength and had a soft feeling. Also PVA
The biodegradability of the wastewater obtained by dissolving and removing the water was good, and the decomposition rate was 95%.

Example 9 The PVA used in Example 2 and the polylactic acid having a D-form content of 1% (melting point: 170 ° C.) were melted and kneaded with different extruders, and modified PVA and polylactic acid were mixed with each other. Into a spinning pack at 240 ° C., and winds 11 layers of modified PVA and polylactic acid at a ratio of 1: 2 (6 layers of polylactic acid, 5 layers of modified PVA) at a spinning speed of 800 m / min. Was. The obtained spun yarn was drawn three times in a hot-air oven at 150 ° C., and cut into 5 mm to obtain cut fibers. After the cut fiber was thrown into water and agitated and dispersed, the dispersion was made through an 80 mesh stainless steel wire mesh. The composite fiber was divided and entangled in a stream of water of 80 kg / cm ² , and subsequently immersed in hot water of 95 ° C. for 1 hour to remove the modified PVA to obtain a sheet. This sheet had a sufficient strength and a soft feel. The extracted PVA solution was recovered and examined for biodegradability, which was 97%.

Example 10 The PVA used in Example 1 was converted to 240
C., melt-kneaded, guide the molten polymer stream to the spinning head, discharge from a spinneret having a hole diameter of 0.25 mm and 24 holes,
The spun yarn is guided to a circular suction / injection device while being cooled by cooling air at 20 ° C., and is drawn and thinned at a take-up speed of 3000 m / min, and the opened filament group is placed on a movable collection conveyor device. By collecting and depositing, a long fiber web was formed. This web was heated at a temperature of 160 ° C. between an embossed roll and a flat roll, and a linear pressure of 20 kg / c.
m under pressure and thermocompression-bonded with embossing, monofilament fineness of 4.3 dtex long fiber, basis weight 30 g / m
^Two long-fiber nonwoven fabrics were obtained. When this nonwoven fabric was put into warm water at 95 ° C., it was dissolved without stopping the original nonwoven fabric form, and the PVA solution after dissolution was recovered to examine the biodegradability.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) D04B 1/16 D04B 1/16 4L048 21/00 21/00 B D06M 11/05 D06M 101: 24 // D06M 101: 24 9/02 CF term (reference) 4L002 AA05 AA07 AB02 AB05 AC00 AC04 DA00 EA00 FA06 4L031 AA16 AB01 AB08 CA06 CA17 DA00 4L035 BB31 BB33 BB56 BB77 BB89 BB91 CC03 CC07 CC20 DD15 DD19 EE01 EE10 FF10 JJ10 FF10 JJ10 FF10 EE08 FF20 4L036 MA04 MA39 PA01 PA46 UA01 UA25 4L041 AA07 AA20 BA04 BA05 BA16 BA49 BA59 BC20 BD11 BD14 CA05 CA55 DD01 DD11 DD14 EE14 4L048 AA18 AA20 AA21 AA42 AA46 AB01 AB07 AB08 AB09 AB12 AC00 AC19 BA01 BA02 CA00 DA24

Claims (8)

[Claims] 1. The content of a 1,2-glycol bond is 1.
A thermoplastic polyvinyl alcohol fiber containing at least one component of polyvinyl alcohol of 8 mol% to 3.5 mol%. 2. The content of a 1,2-glycol bond is 1.
A composite fiber comprising polyvinyl alcohol having a mole percentage of 8 to 3.5 mole% and another thermoplastic polymer having a melting point of 270 ° C. or lower. 3. The fiber according to claim 1, wherein the degree of saponification of the polyvinyl alcohol is from 96 mol% to 99.96 mol%. 4. The fiber according to claim 1, wherein the polyvinyl alcohol is a modified polyvinyl alcohol containing 1 to 20 mol% of α-olefin units having 4 or less carbon atoms. 5. The fiber according to claim 4, wherein the α-olefin unit having 4 or less carbon atoms is an ethylene unit. 6. The fiber according to claim 1, wherein the polyvinyl alcohol contains a plasticizer. 7. A fibrous structure comprising the fiber according to any one of claims 1 to 6. 8. A method for producing a fiber product, comprising treating the fiber structure according to claim 7 with water to dissolve and remove polyvinyl alcohol constituting the fiber.