JP2001262456A - Nonwoven fabric comprising multicomponent long fiber and method for producing the nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new filament nonwoven fabric based on a thermoplastic resin imparted with the character of a PVA-based polymer such as hydrophilicity and water absorptivity through melt spinning process, and to provide a material for a new thermoplastic resin-based long-fibre nonwoven fabrics, having a modified cross-section or ultrafineness and obtained by water extraction of a PVA-based polymer as a component of a conjugate long-fibre nonwoven fabric. SOLUTION: The nonwoven fabric comprises conjugate long-fibre composed of (C) a hydrophilic thermoplastic polyvxnyl alcohol based on (A) a polyvinyl alcohol 90-99.99 mol% in saponification degree and 160-230 deg.C in melting point and containing (B) 0.00001-0.3 mass %, based on 100 mass % of the component A, of alkali metal ion and (D) a thermoplastic polymer <=270 deg.C in melting point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hydrophilic thermoplastic polyvinyl alcohol having a specific composition and a melting point of 270 ° C.
The present invention relates to a nonwoven fabric composed of multicomponent long fibers comprising the following thermoplastic polymer and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, polyvinyl alcohol (hereinafter referred to as P
VA-based fibers) have been industrially produced by wet spinning or dry spinning. Also, recently, a solvent-based wet cooling gel spinning method has been adopted, and it has become possible to impart various performances which have been difficult with conventional methods. PVA is essentially a hydrophilic polymer,
It is known that the degree of hydrophilicity can be changed by its basic skeleton, molecular structure, form and various modifications. In addition, it has been confirmed that PVA is basically biodegradable. At present, how to harmonize a synthetic material with the natural world is becoming a major issue in terms of the global environment. At present, PVA-based polymers and PVA-based fibers having such basic performance have attracted much attention. However, all of these methods spin out a PVA-based solution containing a solvent from a fine-hole nozzle, so that productivity such as a low actual discharge amount of a fiber component and a need to remove a medium after spinning is required. It has the inevitable necessity to get worse. In addition, there are restrictions such as the necessity of large-scale manufacturing facilities specific to the work environment, disaster prevention, and environmental pollution countermeasures.

[0003] On the other hand, the melt spinning method is a method in which a raw material polymer is heated and melted, spun from a fine hole nozzle as it is, and cooled to solidify to form a fiber. It is rational because it is possible and the equipment is versatile. However, the application of PVA to the melt spinning process has two major fundamental obstacles. One of the obstacles is that PVA itself lacks the stability in the molten state required for melt spinning because the melting point and the thermal decomposition temperature are extremely close, and the other is water-soluble,
For fibers that show strong affinity for water, such as water absorption and water swelling, the treatment with aqueous treatment liquids that are usually used in the spinning process after melt spinning such as oil application and drawing is greatly restricted in the process passage. That is.

On the other hand, from the viewpoint of nonwoven fabric production technology, a so-called spun-pound nonwoven fabric production technology for applying such a rational melt spinning method to a thermoplastic resin and directly forming the obtained long fiber into a nonwoven fabric is as follows. This is an extremely rational production method since a nonwoven fabric can be obtained directly from a raw material polymer, and is widely used. In the production of a so-called dry nonwoven fabric, in which a fiber is once produced and the fiber is carded into a nonwoven fabric, an oil agent appropriately selected for the production of the fiber is applied to the fiber surface by passing through various processes in the production of the fiber. This oil deposit is essential for the carding of greasy and nonwoven webs and is usually treated with aqueous treatment liquids. However, PV showing strong affinity for water
In the case of A-based fibers, an aqueous treatment liquid cannot be used. For this reason, it was necessary to use an organic solvent-based special compounding treatment solution and implement large-scale equipment measures. as a result,
There has been a great limitation in producing such a nonwoven fabric using fibers as a raw material while maintaining desired quality.

[0005] In this regard, in the case of the spun bond method, since long fibers obtained by melt spinning are directly formed into a nonwoven fabric, oil treatment is not required, and it can be said that this is a very rational method. Therefore, a nonwoven fabric composed of PVA-based fibers exhibiting strong affinity for water, such as water solubility, water absorption, hydrophilicity, and water swellability, can be manufactured by a spunbond nonwoven manufacturing technology by a melt spinning method. Had been a challenge for many years. Furthermore, a nonwoven fabric composed of a composite fiber of a PVA-based resin lacking stability in a molten state and another thermoplastic resin described above can be manufactured by a spunbond nonwoven fabric manufacturing technique by a melt spinning method. That was a strong request for many years.

[0006] Attempts to apply the technique for producing a so-called spunbonded nonwoven fabric using a rational melt-spinning method to the production of PVA-based long fibers have been conventionally studied. First, JP-A-51-112980 discloses an average degree of polymerization of 50 to 300 and a residual acetic acid group of 15 to 80.
A PVA system in which a filament group obtained by melt-extruding an anhydrous PVA of mol% is aligned with a filament group of a single fiber or another fiber, or separately drawn by a suction jet, and sprayed and deposited on a nonwoven sheet forming surface by a jet stream. A method for producing a synthetic fiber nonwoven fabric has been proposed. However,
PVA having an average degree of polymerization of 50 to 300 and remaining acetic acid groups of 15 to 80 mol% can be obtained for a very short time without producing a nonwoven fabric. The acetic acid gas not only deteriorates the working environment, but also causes gelation due to cross-linking due to intermolecular deacetic acid, which increases the melt viscosity, mixes the gel into the spun polymer stream, and reduces the polymer flow. Problems such as cutting and clogging of filters have occurred, and have not yet reached the level of industrial production.

Next, JP-A-5-345013 discloses that water is soluble only at a temperature exceeding 50 ° C.
A spunbonded nonwoven fabric, that is, a long-fiber nonwoven fabric, is described as a standalone thermoplastic polymer woven fabric of PVA fibers that is insoluble at a temperature of not more than ° C. However, the publication states that, regarding the constituent polymer, "consisting of a highly crystallized PVA homopolymer by post-drawing or thermal annealing" or "suitable for the present invention is a highly crystallized, totally saponified polyvinyl. Although it is described as "acetate," there is no further description of the constituent polymer, and no specific measures concerning the technology for producing a PVA-based long-fiber nonwoven fabric by a melt spinning method are disclosed. Further, Japanese Patent Application Laid-Open
-140758 and JP-A-11-140759
The publication states that certain Ps that are water-soluble at temperatures
A method for producing a spunbond nonwoven fabric is described, which uses a resin in which VA or a plasticizer is added to VA. Japanese Patent Application Laid-Open No. H11-140760 describes a method for producing a spunbonded nonwoven fabric, characterized by using oxyalkylene group-containing PVA. However, these publications relate to a method for producing a spunbonded nonwoven fabric consisting solely of PVA.

Although it is not a spunbonded nonwoven fabric directly connected to melt spinning, as an example of a PVA-based long-fiber nonwoven fabric, Japanese Patent Application Laid-Open No. 7-54257 discloses a single fiber fineness of 1 denier or more and 5 denier or less. Are bonded by a water-soluble resin having an adhesion amount of 5% by mass or more and 25% by mass or less,
A PVA-based long-fiber nonwoven fabric in which the nonwoven fabric has a dissolution temperature in water of 60 ° C or more and 100 ° C or less is described. The publication states that, among PVA-based water-soluble polymers, the dissolution temperature in water can be freely controlled by modifying species, the amount of modification, distribution of modifying groups, etc., and high strength and suitable elongation can be achieved by adopting suitable production conditions. Degree of water-soluble fiber is obtained. The PVA-based filament forming the nonwoven fabric has a saponification degree of 90% or more.
It is described that it can be produced by various known spinning and drawing methods using PVA of 9% or less as a raw material. However, this publication does not specifically describe thermoplastic PVA-based polymers, and does not disclose any technical suggestion of PVA-based fibers by multi-component melt-spinning of the present invention as well as melt spinning.

Further, JP-A-7-279026 discloses a PVA-based polymer (A) having a melting point of 210 ° C. or higher.
And a water-soluble polymer (B) having a melting point of less than 210 ° C.
And the mass ratio between (A) and (B) is 98: 2 to 55:
(A) is a sea component and (B) is a sea-island structure PVA-based long fiber in which an island component is contained. A PVA-based long-fiber nonwoven fabric that is extruded and bonded between fibers has been proposed. However, as described above,
JP-A-54257 and JP-A-7-279026 disclose a PVA-based long-fiber nonwoven fabric by a manufacturing method in which a wound fiber is formed into a nonwoven fabric in a separate step. No technical disclosure suggesting fibers and nonwovens.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a PVA-based nonwoven fabric (a so-called PVA-based nonwoven fabric comprising a multi-component long fiber of a melt-spun PVA-based polymer and another thermoplastic resin) which has not been achieved by the prior art. Spunbonded nonwoven fabric) and a method for producing the same. Furthermore, hydrophilicity,
A novel long-fiber nonwoven fabric mainly composed of a thermoplastic resin imparted with characteristics of a PVA-based polymer such as water absorption and high toughness, and a PVA-based polymer which is one component of a multi-component long fiber after forming the nonwoven fabric is extracted with water. Accordingly, an object of the present invention is to provide a novel thermoplastic resin-based long-fiber nonwoven fabric material having an irregular cross section or an ultrafine fineness.

[0011]

That is, according to the present invention, a saponification degree is 90 to 99.99 mol%, and a melting point is 160 ° C to 23 ° C.
It is composed of PVA (A) having a temperature of 0 ° C., and alkali metal ions (B) are contained in an amount of 0.00000 per 100 parts by mass of (A)
1 to 0.3 parts by mass of hydrophilic thermoplastic PVA
(C) and a thermoplastic polymer having a melting point of 270 ° C. or less (D)
Non-woven fabric composed of multi-component long fibers consisting of
(Hereinafter, sometimes simply referred to as a multi-component long-fiber nonwoven fabric)
And polyvinyl alcohol (A) having a degree of saponification of 90 to 99.99 mol% and a melting point Tm of 160 to 230 ° C., and (A) 100 parts by mass of an alkali metal ion (B) Thermoplastic polymer (C) containing 0.00001 to 0.3 parts by mass of a thermoplastic polymer (D) having a melting point of 270 ° C. or less
When the melting point of a polymer having a higher melting point among the polymer (A) and the polymer (C) is Mp, the spinneret temperature M
After melt-spinning at a temperature of p + 10 ° C. to Mp + 80 ° C., the spun filament group is drawn and thinned by a suction / injection device, and then the opened filaments are collected and deposited on a mobile collecting conveyor device. A method for producing a multicomponent long-fiber nonwoven fabric, characterized by forming a fibrous web. The multi-component filaments constituting the nonwoven fabric of the present invention are those having a melting point of 270 ° C.
As long as the fiber contains the following thermoplastic polymer (D) as an essential component, it may be composed of three or more kinds of polymers.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The polyvinyl alcohol (PVA) in the present invention includes not only a homopolymer of PVA but also a modified PVA having a functional group introduced by copolymerization, terminal modification, and post-reaction. It is.

The degree of saponification of the PVA used in the present invention is 9
It must be between 0 and 99.99 mol%. 93-9
9.98 mol% is preferable, 94-99.97 mol% is more preferable, and 95-99.96 mol% is particularly preferable. If the degree of saponification is less than 90 mol%, the thermal stability of PVA is poor, so that a satisfactory multicomponent melt spinning cannot be performed due to thermal decomposition or gelation, and the multicomponent system of the present invention directly connected to melt spinning. Long-fiber non-woven fabrics cannot be made. On the other hand, PVA having a degree of saponification of more than 99.99 mol% cannot be produced stably, and naturally, it is not possible to produce a stable fibrillation and a multicomponent long-fiber nonwoven fabric directly connected thereto.

The viscosity-average degree of polymerization (hereinafter simply referred to as degree of polymerization) of the PVA used in the present invention depends on the type and polymerization of the PVA-based polymer and the thermoplastic polymer which is another component constituting the multi-component long fiber. Although it depends on the degree (melt viscosity), 100 to 1000 is preferable, and 150 to 70 is preferable.
0 is preferable, and 200 to 500 is particularly preferable. If the degree of polymerization is less than 100, sufficient spinnability may not be obtained during spinning, and as a result, a satisfactory multicomponent long-fiber nonwoven fabric may not be obtained. On the other hand, when the degree of polymerization is 100
If it exceeds 0, the melt viscosity is too high, and the melt viscosity matching with the thermoplastic resin constituting other components to be combined may become inappropriate or the polymer may not be discharged from the spinning nozzle. In some cases, a system long fiber nonwoven fabric cannot be obtained.

The degree of polymerization (P) of PVA is determined according to JIS-K67.
26 is measured. That is, it is obtained by the following equation from the intrinsic viscosity [η] (dl / g) measured in water at 30 ° C. after completely saponifying and purifying PVA. 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 melting point (Tm) of PVA used in the multicomponent long-fiber nonwoven fabric of the present invention is 160 to 230 ° C., and 165 to 228 ° C.
Is preferable, and 170 to 226 ° C is more preferable. 160 ° C melting point
If it is less than 1, the crystallinity of the PVA decreases, the strength of the nonwoven fabric constituent fibers decreases, and the strength of the nonwoven fabric itself decreases. In some cases, the spinnability required for the multi-component melt spinning is lost or the thermal decomposition of PVA is severely generated, so that a multi-component long fiber nonwoven fabric may not be obtained. On the other hand, the melting point
If the temperature exceeds 230 ° C., the melt spinning temperature of the multi-component system must be increased in order to secure a suitable melt viscosity, and other thermoplastic resins to be composited are not only limited, but also the spinning temperature and the decomposition temperature of PVA. Therefore, stable melt spinning cannot be performed, and a stable PVA-based multicomponent long-fiber nonwoven fabric cannot be manufactured.

The melting point of PVA is determined by using DSC
After heating to 250 ° C at a heating rate of 10 ° C / min, cool to room temperature,
PVA when heated up to 250 ° C again at a heating rate of 10 ° C / min
Means the temperature at the peak top of the endothermic peak indicating the melting point. Further, as long as the objects and effects of the present invention are not impaired, PV
A can be added with a plasticizer for the purpose of adjusting the melting point and the melt viscosity. As the plasticizer, all conventionally known plasticizers can be used, and those obtained by adding ethylene oxide and propylene oxide to diglycerin, polyglycerin alkyl monocarboxylic acid esters, and glycols are preferably used. Among them, a compound obtained by adding 1 to 30 mol% of ethylene oxide to 1 mol of sorbitol is preferable.

PVA can be obtained by saponifying vinyl ester units of a vinyl ester polymer. Vinyl compound monomers for forming vinyl ester units include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate and Examples thereof include vinyl versatate, and among them, vinyl acetate is preferred from the viewpoint of obtaining PVA.

The PVA, which is one component of the multicomponent long-fiber nonwoven fabric of the present invention, may be a homopolymer or a modified PVA into which copolymerized units have been introduced. From the viewpoint of the physical properties of the fiber and the nonwoven fabric, it is preferable to use a modified PVA into which copolymerized units have been introduced.
Examples of the type of the comonomer include α, such as ethylene, propylene, 1-butene, isobutene, and 1-hexene.
-Olefins, acrylic acid and its salts, methyl acrylate, ethyl acrylate, n-propyl acrylate,
Acrylic esters such as i-propyl acrylate, methacrylic acid and salts thereof, methacrylic esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, acrylamide, N-methylacrylamide , Acrylamide derivatives such as N-ethylacrylamide, methacrylamide, N-methylmethacrylamide, methacrylamide derivatives such as N-ethylmethacrylamide, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether Such as vinyl ethers such as ethylene glycol vinyl ether, 1,3-propanediol vinyl ether, and 1,4-butanediol vinyl ether; Ether compounds, allyl acetate,
Allyl ethers such as propyl allyl ether, butyl allyl ether and hexyl allyl ether, monomers having an oxyalkylene group, vinyl silyls such as vinyl trimethoxysilane, isopropenyl acetate, 3-butene-
Hydroxy such as 1-ol, 4-penten-1-ol, 5-hexen-1-ol, 7-octen-1-ol, 9-decen-1-ol, and 3-methyl-3-buten-1-ol; Group-containing α-olefins, N-vinylamides such as N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, fumaric acid, maleic acid, itaconic acid, maleic anhydride, phthalic anhydride, trimellitic anhydride Or a monomer having a carboxyl group derived from itaconic anhydride or the like; a monomer having a sulfonic acid group derived from ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, or the like Body: vinyloxyethyltrimethylammonium chloride, vinyloxybutyltrimethylammonium chloride Ride, vinyloxy ethyl dimethylamine, vinyloxy methyldiethylamine, N- acrylamidomethyl trimethylammonium chloride, N
And monomers having a cationic group derived from acrylamidoethyltrimethylammonium chloride, N-acrylamidodimethylamine, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, dimethylallylamine, allylethylamine and the like. The content of these monomers is usually 20 mol% or less.

Among these monomers, α-olefins such as ethylene, propylene, 1-butene, isobutene and 1-hexene, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, Vinyl ethers such as i-propyl vinyl ether and n-butyl vinyl ether; hydroxy group-containing vinyl ethers such as ethylene glycol vinyl ether, 1,3-propanediol vinyl ether and 1,4-butanediol vinyl ether; allyl acetate, propyl allyl ether and butyl Allyl ether,
Allyl ethers such as hexyl allyl ether; N-vinylamides such as N-vinylformamide, N-vinylacetamide and N-vinylpyrrolidone; monomers having an oxyalkylene group; 3-buten-1-ol;
Penten-1-ol, 5-hexen-1-ol, 7
-Octen-1-ol, 9-decene-1-ol, 3
Monomers derived from hydroxy group-containing α-olefins such as -methyl-3-buten-1-ol are preferred.

Particularly, from the viewpoints of copolymerizability, melt spinnability and fiber properties, ethylene, propylene, 1-butene and isobutene having 4 or less carbon atoms, α-olefins, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, Vinyl ethers such as i-propyl vinyl ether and n-butyl vinyl ether, and N-vinyl amides such as N-vinyl formamide, N-vinyl acetamide and N-vinyl pyrrolidone are more preferable. Α-olefins having 4 or less carbon atoms, vinyl ethers and N
-Units derived from vinylamides are 0.1% in PVA.
Preferably, it is present in an amount of up to 20 mol%, more preferably 1 to 15 mol%. Furthermore, when the α-olefin is ethylene, the fiber properties are increased,
In particular, the ethylene unit has 3 to 18 mol%, more preferably 5 to 18 mol%.
It is preferable to use modified PVA in which 〜15 mol% is introduced.

The PVA used in the present invention is a bulk polymerization method,
Known methods such as 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. Alcohol used as a solvent during solution polymerization includes methyl alcohol, ethyl alcohol,
Lower alcohols such as propyl alcohol are exemplified. As the initiator used for the copolymerization, α, α′-azobisisobutyronitrile, 2,2′-azobis (2,4
-Dimethyl-valeronitrile), benzoyl peroxide, n
Examples of the initiator include known initiators such as azo initiators such as -propyl peroxycarbonate and peroxide initiators. The polymerization temperature is not particularly limited.
A range of 0 ° C. is appropriate.

The content ratio of the alkali metal ion (B) in the PVA (A) used in the present invention is as follows.
0.000 in terms of sodium ion with respect to 00 parts by mass
0.01 to 0.3 parts by mass, preferably 0.00005 to 0.1 parts by mass, more preferably 0.0001 to 0.07 parts by mass, and particularly preferably 0.0002 to 0.05 parts by mass. When the content ratio of the alkali metal ion is less than 0.00001 parts by mass, it is difficult to produce industrially. When the content of the alkali metal ion is more than 0.3 parts by mass, decomposition, gelation and breakage during melt spinning are remarkable, and the fiber cannot be stably formed. Note that examples of the alkali metal ion include a potassium ion and a sodium ion.

In the present invention, the method of adding a specific amount of alkali metal ion (B) to PVA is not particularly limited, and a method of adding an alkali metal ion-containing compound after polymerizing PVA, a method of vinyl ester polymer When saponifying in a solvent, an alkali metal ion-containing alkaline substance is used as a saponification catalyst to mix the alkali metal ions in the PVA, and the PVA obtained by saponification is washed with a washing solution, so that the PVA For controlling the content of alkali metal ions contained in the above, but the latter is more preferable. The content of the alkali metal ion can be determined by an atomic absorption method.

The alkaline substance used as the saponification catalyst includes potassium hydroxide or sodium hydroxide. The molar ratio of the alkaline substance used in the saponification catalyst is preferably from 0.004 to 0.5, particularly preferably from 0.005 to 0.05, based on the vinyl acetate unit. The saponification catalyst may be added all at once in the early stage of the saponification reaction, or may be additionally added during the saponification reaction. Examples of the solvent for the saponification reaction include methanol, methyl acetate, dimethyl sulfoxide, dimethylformamide and the like. Of these solvents, methanol is preferred, and the water content is 0.1%.
Methanol controlled at 001 to 1% by mass is more preferable, methanol controlled at a water content of 0.003 to 0.9% by mass is more preferable, and methanol controlled at a water content of 0.005 to 0.8% by mass is preferable. Particularly preferred. Examples of the washing liquid include methanol, acetone, methyl acetate, ethyl acetate, hexane, water and the like, and among them, methanol or methyl acetate, water alone or a mixed liquid is more preferable. The amount of the washing liquid is alkali metal ion (B)
Is set to satisfy the content ratio of
The amount is preferably from 300 to 10,000 parts by mass, more preferably from 500 to 5,000 parts by mass, per 100 parts by mass of A. The washing temperature is preferably from 5 to 80 ° C, preferably from 20 to 70 ° C.
Is more preferred. The washing time is preferably from 20 minutes to 100 hours, more preferably from 1 hour to 50 hours.

The 2 in PVA (A) used in the present invention
Acid (E) having an acid group having a pKa of 5.0 or less at 5 ° C.
Is preferably 0.01 to 1, more preferably 0.03 to 0.8, and 0.03 to 0.8.
5-0.6 is more preferred. In the present invention, the content of the acid (E) in the formula of α shown below means a value obtained by neutralization titration converted to acetic acid. The pKa is defined as pKa = -logKa, where Ka is the dissociation constant of the acid. α = [content of acid (E) in polyvinyl alcohol (% by mass)] / [content of alkali metal ion (B) in polyvinyl alcohol (% by mass)] The pKa of acid (E) is 5.0. When an acid having an acid group exceeding the above is used, and when the acid (E) content ratio is 0.
When it is out of the range from 01 to 1, the decomposition, gelation, and breakage of PVA during melt spinning are remarkable, and the fiber may not be stably formed. Examples of the acid (E) having an acid group having a pKa at 25 ° C. of 5.0 or less include acetic acid, phosphoric acid, and sodium monophosphate.

In the present invention, a specific amount at 25 ° C.
The method for incorporating an acid (E) having an acid group with a pKa of 5.0 or less into PVA is not particularly limited, and after saponifying a vinyl ester polymer in a solvent, the acid group with a pKa of 5.0 or less is obtained. A method of controlling the acid content in PVA by blending the acid in PVA by using an acid having the following formula, and washing the PVA obtained by saponification with a washing solution; And a method in which a specific amount of acid is added by adding a specific amount of acid when preparing PVA pellets, and the like. The acid content is
It can be determined by neutralizing and titrating the methanol extract from PVA with an aqueous sodium hydroxide solution.

The 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. The activated sludge method is preferable for treating the waste liquid after dissolving the PVA. When the PVA aqueous solution is continuously treated with activated sludge, it is decomposed in 2 days to 1 month. In addition, since PVA used in the present invention has a low combustion heat and a small load on an incinerator, the PVA may be incinerated by drying the wastewater in which the PVA is dissolved.

The PVA (C) used in the present invention has a melting point of 27.
The mass ratio between (C) and (D) of the multicomponent continuous fiber composed of the thermoplastic polymer (D) having a temperature of 0 ° C. or lower is not particularly limited because it is appropriately set according to the purpose. / 5 is preferred, and 10/90 to 90/10 is more preferred.
Outside the preferred range, the combined or mixed effects may not be exhibited. The melting point used in the present invention is 27.
Thermoplastic polymers at 0 ° C. or lower include, for example, aromatic polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyhexamethylene terephthalate;
Polylactic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvalerate copolymer, aliphatic polyesters such as polycaprolactone and copolymers thereof, nylon 6, nylon 66, Aliphatic polyamides such as nylon 10, nylon 12, and nylon 6-12 and copolymers thereof, polyolefins such as polypropylene, polyethylene, polybutene and polymethylpentene and copolymers thereof, and 25 mol% of ethylene units
To 70% by mole of modified polyvinyl alcohol, polystyrene, polydiene, chlorine, polyolefin, polyester, polyurethane, polyamide,
At least one kind can be selected from fluorine-based elastomers and the like. Polybutylene terephthalate, polylactic acid, nylon 6, nylon 6-12, polypropylene, and modified polyvinyl alcohol containing 25 to 70 mol% of ethylene units are preferable from the viewpoint of easy multicomponent spinning with the PVA used in the present invention. .

In addition, as long as the objects and effects of the present invention are not impaired, a stabilizer such as a copper compound, a coloring agent, an ultraviolet absorber, etc. may be added to the thermoplastic PVA and the thermoplastic polymer having a melting point of 270 ° C. or less, if necessary. Light stabilizers, antioxidants, antistatic agents, flame retardants, plasticizers, lubricants, and crystallization rate retarders can be added during the polymerization reaction or in a subsequent step.
In particular, when organic stabilizers such as hindered phenol, copper halides such as copper iodide, and alkali metal halides such as potassium iodide are added as heat stabilizers, the melt retention stability during fiberization is improved. Is preferred.

If necessary, the average particle size is 0.01 μm.
Fine particles having a size of not less than m and not more than 5 μm can be added at 0.05 to 10% by mass 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.

Next, a method for producing a multi-component nonwoven fabric composed of long fibers composed of PVA (C) used in the present invention and a thermoplastic polymer (D) having a melting point of 270 ° C. or less will be described. Multi-component nonwoven fabric composed of long fibers of the present invention,
It can be efficiently produced by a method for producing a so-called spunbonded nonwoven fabric directly connected to melt spinning. For example,
In the method by mixed spinning, the PVA component (C) and the thermoplastic polymer (D) are melt-kneaded with one extruder,
The molten polymer stream is guided to the spinning head, the flow rate is measured and discharged from the spinning nozzle hole.The discharged yarn is cooled by a cooling device, and the target fineness is determined using a suction device such as an air jet nozzle. 1000 to 60
After the yarn is drawn down at a speed corresponding to the yarn take-up speed of 00 m / min by a high-speed air stream, it is deposited on a movable collecting surface while opening the fiber to form a nonwoven fabric web. By partially pressing and winding
An A-based multicomponent long-fiber nonwoven fabric is obtained.

In the method by composite spinning, the PVA component (C) and the thermoplastic polymer (D) are melt-kneaded by different extruders, and the same molten polymer stream is guided to the spinning head, and the flow rate is measured. After discharging from the spinning nozzle hole, a composite long-fiber nonwoven fabric can be obtained in the same manner as in the above-described mixed spinning. The composite form of the composite long fiber constituting the composite long-fiber nonwoven fabric 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 bonding type, a radial division type, or a combination thereof.

In the present invention, the fiberization conditions constituting the multicomponent long-fiber nonwoven fabric need to be appropriately set according to the combination of the polymers and the cross-sectional shape. It is desirable to determine the fiberization conditions. The spinneret temperature is Mp + 10 when the melting point of a polymer having a high melting point among the polymers constituting the multi-component continuous fiber is Mp.
Mp + 80 ° C is preferred, and shear rate (γ) 500-25,000s
It is preferred to spin at ec ^-1 and draft V50-2000. In addition, when viewed from the combination of polymers, it is preferable from the viewpoint of spinning stability that a multicomponent spinning is performed by combining polymers having melt viscosities close to each other as measured by a die temperature during spinning and a shear rate when passing through a nozzle. .

The melting point Tm of PVA in the present invention is a peak temperature of a main endothermic peak observed by a differential scanning calorimeter (DSC: for example, TA3000 manufactured by Mettler). The shear rate (γ) is calculated as γ = 4Q / πr ³ when the nozzle radius is r (cm) and the amount of polymer discharged per single hole is Q (cm ³ / sec). The draft V is calculated as V = (A · πr ² / Q) × (5/3), where the take-off speed is A (m / min).

In the production of the multicomponent fiber of the present invention, when the spinneret temperature is lower than the melting point Mp + 10 ° C. of the polymer having a high melting point among the polymers constituting the multicomponent filament, the melt viscosity of the polymer is reduced. If it is too high, it is inferior in spinning and thinning properties due to high-speed airflow. If it exceeds Mp + 80 ° C., PVA is easily thermally decomposed, so that stable spinning cannot be performed. Further, the shear rate is easily Dan'ito lower than 500sec ^-1, 25,000sec ^- high spinning property becomes high back pressure of the nozzle than ¹ deteriorates. If the draft is lower than 50, the fineness unevenness increases and it becomes difficult to spin stably, and if the draft is higher than 2000, the yarn is easily broken.

In the present invention, when the discharge yarn is drawn and thinned using a suction device such as an air jet nozzle, it is pulled by a high-speed airflow at a speed corresponding to a yarn take-up speed of 1000 to 6000 m / min. It is important to reduce the size. The yarn take-up conditions by the suction device are: melt viscosity of the molten polymer discharged from the spinning nozzle hole, discharge speed,
It is appropriately selected depending on the spinning nozzle temperature, cooling conditions, etc.
If it is less than 1000 m / min, fusion between adjacent yarns may occur due to delay in cooling and solidification of the discharged yarns, and the orientation and crystallization of the yarns do not proceed. It is not preferable because it becomes low. On the other hand, 6
If it exceeds 000 m / min, the threading / thinning properties of the discharged yarn cannot follow, and the yarn is cut, so that a stable multicomponent long-fiber nonwoven fabric cannot be produced. Furthermore, in stably producing the PVA-based multicomponent long-fiber nonwoven fabric of the present invention, it is important that the distance between the spinning nozzle hole and a suction device such as an air jet nozzle is 30 to 200 cm. The distance depends on the polymer used, the composition, and the spinning conditions described above, but if the distance is less than 30 cm, fusion between adjacent yarns may occur due to delay in cooling and solidification of the discharged yarn. Further, the orientation and crystallization of the yarn do not proceed, and the resulting nonwoven fabric is undesirably coarse and has low mechanical strength. On the other hand, when the length exceeds 200 cm, the cooling and solidification of the discharged yarn progresses too much, so that the drawing and thinning properties of the discharged yarn cannot follow, and the yarn is cut. Cannot be manufactured.

In the present invention, the thus obtained PV
The method of maintaining the shape of the A-based multi-component nonwoven web by partial heat and pressure fusion is adopted. Specifically, the long fibers are bonded by partial thermocompression through the web between a heated metal roll (embossing roll) and a heated smoothing roll to stabilize the form as a nonwoven fabric. . The temperature of the heating roll, the pressure for applying heat and pressure, the processing speed, the pattern of the embossing roll, and the like in the thermocompression bonding can be appropriately selected depending on the purpose. The PVA-based multi-component long fibers constituting the nonwoven fabric according to the present invention are active against water and have an apparent melting point lowering in the presence of water. Can lower the temperature of the heating roll. Furthermore, the PVA-based multi-component nonwoven web whose shape has been maintained by hot-pressure fusion can be subjected to a heat treatment if necessary.

The important point of the thermoplastic PVA-based multi-component long-fiber nonwoven fabric of the present invention is that, as described above, the melt spinning method, which was conventionally difficult, is applied, and the hydrophilicity, water absorption,
Unusual cross-section or ultrafine fineness of water-extracted PVA-based polymer, which is one component of long-fiber nonwoven fabric mainly composed of a novel thermoplastic resin and multi-component long-fiber nonwoven fabric, which is provided with characteristics of PVA-based polymer such as high toughness Another object of the present invention is to provide a novel thermoplastic resin-based long-fiber nonwoven fabric material having the following. Accordingly, the present invention provides mechanical properties and thickness such as fineness and fiber cross-sectional shape of the multi-component long fibers constituting the nonwoven fabric or the basis weight and tensile strength of the nonwoven fabric, tensile elongation and tear strength,
The morphological characteristics such as bulkiness and the characteristics such as flexibility are not particularly limited, and can be appropriately selected usually within a settable range.

In addition, when a novel material for a thermoplastic resin-based long-fiber nonwoven fabric having a modified cross section or ultrafineness is obtained by extracting a PVA-based polymer, which is one component of the multi-component long-fiber nonwoven fabric, with water, The aqueous solution for extracting the PVA-based polymer may be neutral, and may be an alkaline aqueous solution, an acidic aqueous solution, or an aqueous solution to which a surfactant or the like is added. The extraction processing temperature may be appropriately adjusted according to the purpose, but the higher the processing temperature, the shorter the processing time. When extraction is performed using hot water, the treatment is preferably performed at 50 ° C. or higher, and particularly preferably performed at 80 ° C. or higher. The novel thermoplastic resin-based long fiber having an irregular cross section or extra fineness after extraction can be formed into a nonwoven fabric by a conventionally known method.

The thermoplastic PVA-based multicomponent long-fiber nonwoven fabric of the present invention can be used for air-conditioning materials such as liquid, gas, and dust collecting filters, wipers such as lint-free wipers and various wiping cloths, insulating materials, and electronics such as battery separators. Materials such as oil sorbents, leather base materials, compound materials for cement, compound materials for rubber, various tape base materials, embroidery base materials, etc .; medical equipment such as disposable diapers, gauze, hot ties, medical gowns, surgical tapes, etc. Life-related materials such as base materials for printed matter, packaging and bag materials, wipers, and storage materials; clothing; construction materials; agricultural and horticultural materials; soil stabilizing materials, filtration materials, sediment prevention materials, vegetation mats, Civil engineering such as reinforcement
For materials; can be used for applications such as bag shoes. Furthermore, not only the multicomponent long-fiber nonwoven fabric obtained in the present invention can be used alone, but also it can be used by laminating with a nonwoven fabric manufactured by another method such as a homo long-fiber nonwoven fabric, a melt-blown nonwoven fabric, and the like. Yes, when used for the above applications, practical functions can be further provided.

[0042]

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, each property value was measured as follows.
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 is 500 MHz 1H-NMR (JEOL GX-50) using modified polyvinyl ester or modified PVA.
0) It was determined from measurement by an apparatus. The content of the alkali metal ion was determined by an atomic absorption method.

[Method of Analyzing Acid Content in PVA] Using 20 g of absolutely dried PVA, methanol Soxhlet extraction was performed for 3 days using 100 mL of methanol. 50 mL of distilled water and several drops of phenolphthalein were added to 50 mL of the extract, and the acid in the extract was neutralized and titrated with a 1/1000 N aqueous sodium hydroxide solution. The acid content in PVA was converted to acetic acid according to the following equation. Acetic acid (%) = (0.12 × titer mL × 100) / (1
000 × 20)

[Melting point] The melting point of PVA was measured by using DSC (Mettler, TA3000) in nitrogen at a heating rate of 10
The temperature was raised to 250 ° C. at a rate of ° C./min, then cooled to room temperature, and the temperature of the peak top of the endothermic peak indicating the melting point of PVA when the temperature was raised to 250 ° C. at a rate of 10 ° C./min again was examined.

[Spinning State] The state of melt spinning was observed and evaluated according to the following criteria. ◎: extremely good, ○: good, Δ: slightly difficult, ×: poor

[State of Nonwoven Fabric] The obtained nonwoven fabric was visually observed and touched and evaluated according to the following criteria. ◎: Homogeneous and extremely good, ○: Almost homogeneous and good, Δ: Slightly difficult, ×: Poor

[Strength and elongation of nonwoven fabric] JIS L190
6 Measured according to “General Long Fiber Nonwoven Fabric Test Method”.

[Embodiment, thickness] Measured according to JIS L1906 “Test method for general long-fiber nonwoven fabric”.

[Average Fiber Diameter] Using a scanning electron microscope, a photograph of the surface of the nonwoven fabric was magnified 1000 times, and two diagonal lines were drawn on the photograph, and the thickness of the fiber crossing the diagonal line was determined. The value converted to the magnification was used. And then
The average value of 100 fibers was defined as the average fiber diameter.

[Water Absorption of Non-woven Fabric] A non-woven fabric of 20 cm × 20 cm weighed accurately after being completely dried in advance is treated with pure water at 20 ° C.
After being immersed in 0 cc for 30 minutes, it was taken out, the attached water on the surface was wiped off, and the mass was precisely weighed to determine the water absorption of the nonwoven fabric.

[Equilibrium moisture content of nonwoven fabric] 20 ° C., 65% R
After measuring the mass W0 of the nonwoven fabric conditioned for 1 week in H,
Mass W of non-woven fabric dried at 105 ° C. for 5 hours
1 was precisely weighed. The equilibrium water content was determined as 100 × W0 / W1.

[Underwater lintability of nonwoven fabric] 20 cm × 20
cm of non-woven fabric is immersed in a flask containing 500 cc of pure water at 20 ° C.
The amount of lint remaining in the water after being shuffled twice was visually observed, and judged in five steps. Judgment: bad 1-5 good

[Production of Ethylene-Modified PVA] 29.0 kg of vinyl acetate and 31.0 kg of methanol were charged into a 100 L pressurized reaction vessel equipped with a stirrer, a nitrogen inlet, an ethylene inlet and an initiator addition port. After heating 3
The system was replaced with nitrogen by bubbling nitrogen for 0 minutes. Then, ethylene was introduced and charged so that the pressure in the reaction tank was 5.9 kg / cm ² (5.8 × 10 ⁵ Pa). 2, as an initiator
A solution of 2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMV) in methanol at a concentration of 2.8 g / L was prepared and subjected to nitrogen replacement by bubbling with nitrogen gas. After adjusting the internal temperature of the polymerization tank to 60 ° C., 170 ml of the initiator solution was injected to start polymerization. During the polymerization, ethylene was introduced to raise the reaction vessel pressure to 5.9 kg / cm ² (5.8 × 10 ⁵ Pa) and the polymerization temperature to 60 ° C.
610 ml / hr using the above initiator solution.
AMV was continuously added to carry out polymerization. After 10 hours, when the polymerization rate reached 70%, 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.

46.5 g (polyacetic acid) was added to 200 g of a methanol solution of polyvinyl acetate (100 g of polyvinyl acetate in the solution) adjusted to 50% concentration by adding methanol to the obtained polyvinyl acetate solution. Saponification was carried out by adding an alkali solution (10% methanol solution of NaOH) having a molar ratio (MR) of 0.10 relative to the vinyl acetate unit in vinyl. The gelled system in about 2 minutes after the addition of the alkali was pulverized with a pulverizer and left at 60 ° C. for 1 hour to progress the saponification. Then, 0.5% acetic acid in water / methanol = 20/80. 1000 g of the mixed solution was added to neutralize the remaining alkali. After confirming the completion of neutralization using a phenolphthalein indicator, a 20/80 mixed solution of water / methanol = 20/80 was added to white solid PVA obtained by filtration.
000 g was added, and the mixture was left and washed at room temperature for 3 hours. After repeating the above washing operation three times, 1000 g of methanol was further added.
Was added and washed at room temperature for 3 hours. Thereafter, the PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain a dried PVA (PVA-1).

The degree of saponification of the obtained ethylene-modified PVA was 98.4 mol%. After the modified PVA was incinerated, the content of sodium measured by an atomic absorption spectrophotometer using a substance dissolved in an acid was 0.001 part by mass with respect to 100 parts by mass of the modified PVA. Subsequently, 20 g of absolutely dried PVA obtained by vacuum-drying the modified PVA obtained above at 50 ° C. for 10 hours was subjected to methanol-Soxhlet extraction using 100 mL of methanol for 3 days. Extract liquid 50m
L was added to 50 mL of distilled water and several drops of phenolphthalein, and the acid in the extract was measured for acetic acid content by neutralization titration with a 1/1000 N aqueous sodium hydroxide solution.
0.00008 parts by mass with respect to 100 parts by mass of the modified PVA, and the value α representing the ratio of acetic acid to sodium ions in the PVA was 0.08.

Further, a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization is added to n
-Precipitation in hexane and reprecipitation by dissolving in acetone were performed three times, followed by drying under reduced pressure at 80 ° C for 3 days to obtain purified polyvinyl acetate. The polyvinyl acetate was dissolved in DMSO-d6, and 500 MHz proton NMR (JEOL GX
The content of ethylene was 10 mol% as measured at 80 ° C. using (−500). After saponifying the above methanol solution of polyvinyl acetate at an alkali molar ratio of 0.5, the pulverized product was left at 60 ° C. for 5 hours to progress saponification, and then methanol soxhlet was carried out for 3 days, and then 80 ° C. And dried under reduced pressure for 3 days to obtain a purified ethylene-modified PVA. The average degree of polymerization of the PVA was determined by a conventional method, J
It was 330 when measured according to IS K6726. Further, a 5% aqueous solution of the purified modified PVA was adjusted to prepare a cast film having a thickness of 10 μm.
After drying the film under reduced pressure at 80 ° C. for 1 day, D
The melting point of PVA was measured using SC (Mettler, TA3000) by the method described above and found to be 206 ° C. (Table 1).

[0058]

[Table 1]

Example 1 The PVA (PVA-1) obtained above was used as a core component in 9
Vacuum dried at 0 ° C. for 10 hours and propylene having a melt flow rate (MFR) of 35 g / 10 min and a melting point of 170 ° C. as a sheath component were prepared. Each polymer is heated to 235 ° C. ± 1 ° C. by another extruder and melt-kneaded, so that the mass ratio of the core component to the fiber cross section orthogonal to the fiber axis of the composite long fiber constituting the nonwoven fabric becomes 50%. To a core-sheath composite spinning pack at 235 ° C. and a nozzle diameter of 0.
The ejector is ejected from the spinneret under the conditions of 35 mmφ × 1008 holes, a discharge amount of 625 g / min, and a shear rate of 2,500 sec ⁻¹ , and the ejector at a distance of 80 cm from the nozzle while cooling the spun filament group with cooling air at 20 ° C. The filaments were drawn and thinned with a draft 410 at a take-up speed of 2500 m / min with high-speed air, and the opened filament group was collected and deposited on a collecting conveyor device rotating endlessly to form a long fiber web. The spinning state was extremely good without any breakage.

Next, the web was passed under a linear pressure of 50 kg / cm between the embossed pattern embossing roll heated at 130 ° C. and the flat roll under a linear pressure of 50 kg / cm. A core-sheath composite long fiber nonwoven fabric having a basis weight of 30 g / m ^{2 and} comprising 6 decitex long fibers was obtained. The obtained nonwoven fabric was homogeneous and very good. Table 2 shows the production conditions and production results of the composite long-fiber nonwoven fabric.

[0061]

[Table 2]

Table 3 shows the evaluation results of the obtained nonwoven fabrics for tensile strength, tensile elongation, tear strength, water absorption and equilibrium moisture content.

[0063]

[Table 3]

Examples 2 to 13 Instead of the PVA used in Example 1, the PV listed in Table 1 was used.
Example 1 except that A was used, a spinneret for composite spinning having the shape shown in Table 2 and a polymer were used, the spinning conditions shown in Table 2 were adopted, and the distance between the nozzle and the ejector and the line net speed were adjusted. After obtaining a nonwoven web composed of PVA-based composite filaments under the same conditions as described above, the composite filament nonwoven fabric was obtained by partial thermocompression bonding at the embossing temperature shown in Table 2. The mass ratio of the core-sheath component of the core-sheath type composite continuous fibers of Examples 3 and 4 was adjusted by changing the amount of the polymer introduced into the pack. As the sea-island composite long fibers of Examples 5, 6, and 10, a sea-island composite spinning die having 400 islands was used. Table 2 shows the results of the spinnability and the state of the obtained nonwoven fabric. Table 3 shows the evaluation results obtained by testing the obtained nonwoven fabric for tensile strength, tensile elongation, tear strength, water absorption, and equilibrium moisture content.
Shown in

Comparative Examples 1-4 Instead of the PVA used in Example 1, the PV listed in Table 1 was used.
A, a polymer shown in Table 2 was used, spinning conditions were adopted, and a nozzle-ejector distance and a line net speed were adjusted. After obtaining the non-woven web, Table 2
Was subjected to partial thermocompression bonding at the embossing temperature described in (1) to obtain a composite long-fiber nonwoven fabric. Table 2 shows the results of the spinnability and the state of the obtained nonwoven fabric.

When the PVA shown in Comparative Example 1 was used, PV
Due to the generation and gelation of gas containing acetic acid due to thermal decomposition of A, thread breakage occurred frequently, stable fiber formation was not possible, and nonwoven web formation was not possible. In the case where the PVA shown in Comparative Example 2 was used, it is assumed that the crystallinity of the PVA was reduced, but adjacent spun filaments stuck together. Since the non-woven web was formed without being able to release this, the sheet was rough and had a poor tactile sensation. When the PVA shown in Comparative Example 4 was used, a relatively stable spinning state was maintained in a single time of about 30 minutes. However, although the reason is not clear, after 2 hours, thread breakage occurred frequently, stable fiber formation was not possible, and nonwoven web formation was not possible. In Comparative Example 3,
The spinning temperature was raised to 270 ° C. because the melting point of the PVA used was high, but the gel was mixed in the nonwoven fabric. Comparative Example 3
Table 3 shows the evaluation results of tests on the tensile strength, tensile elongation, tear strength, water absorption, and equilibrium moisture content of the nonwoven fabric obtained in the above. The mechanical properties of the non-woven fabric were small, presumably due to the inclusion of a gel.

Example 14 The sea-island composite long-fiber nonwoven fabric of PVA / polypropylene prepared in Example 5 was immersed in hot water at 95 ° C. for 1 hour to remove sea component PVA. When the fineness of the polypropylene filament was measured, it was 0.08 μm, and an ultrafine fiber was obtained.

COMPARATIVE EXAMPLE 5 The polymer used in Example 1 was melt-kneaded with different extruders under the same conditions as in Example 1;
And spinning at a spinning speed of 800 m / min. To form a core-sheath type composite fiber, with a nozzle diameter of 0.4 mmφ × 24 holes, a discharge rate of 24 g / min, a shear rate of 2400 sec ⁻¹ , and a draft of 110. I got Next, the obtained spun yarn was drawn three times in a hot air oven at 150 ° C. to obtain a conjugate fiber having a single fiber fineness of 4.4 decitex. The drawn yarn was crimped by a crimping machine, cut into 50 mm, and made into raw cotton. The raw cotton was carded with a roller card and entangled with a needle punch to form a nonwoven fabric. When the lint-in-water property of the nonwoven fabric was determined, it was Stage 3. On the other hand, when the nonwoven fabric produced in Example 1 was similarly evaluated, it was found to be 4.5.

[0069]

According to the present invention, a novel long-fiber non-woven fabric and a multi-component non-woven fabric mainly comprising a thermoplastic resin imparted with characteristics of PVA-based polymer such as hydrophilicity and water absorption by melt spinning, which cannot be achieved by the prior art. It is possible to provide a novel thermoplastic resin-based long-fiber nonwoven fabric having a modified cross-section or a fine fineness obtained by extracting a PVA-based polymer, which is one component of the long-fiber nonwoven fabric, with water.

Claims (7)

[Claims] 1. A polyvinyl alcohol (A) having a degree of saponification of 90 to 99.99 mol% and a melting point of 160 to 230 ° C., and an alkali metal ion (B) is added to 100 parts by mass of (A). 0.00001 to 0.3 parts by mass of a hydrophilic thermoplastic polyvinyl alcohol (C) and a thermoplastic polymer (D) having a melting point of 270 ° C. or less
A nonwoven fabric characterized by comprising a multicomponent long fiber consisting of: 2. The polyvinyl alcohol (A) contains an acid (E) having an acid group having a pKa of not more than 5.0 at 25 ° C. with respect to the polyvinyl alcohol (A) so as to satisfy the formula (1). 2. Polyvinyl alcohol,
2. The nonwoven fabric according to 1. 0.01 ≦ α ≦ 1 (1) where α = [content of acid (E) in polyvinyl alcohol (% by mass)] / [content of alkali metal ion (B) in polyvinyl alcohol (% by mass)] ] 3. The nonwoven fabric according to claim 1, wherein the polyvinyl alcohol (A) has a viscosity average degree of polymerization of 100 to 1,000. 4. A method according to claim 1, wherein the polyvinyl alcohol (A) is an α-olefin unit having 4 or less carbon atoms, a vinyl ether unit,
At least one of vinylamide units is 0.1 to 2;
The nonwoven fabric according to any one of claims 1 to 3, which is a modified polyvinyl alcohol containing 0 mol% and having a viscosity average polymerization degree of 200 to 500. 5. The thermoplastic polymer (D) is at least one thermoplastic polymer selected from the group consisting of polyesters, polyamides, polyolefins and modified polyvinyl alcohol containing 25 to 70 mol% of ethylene units. Item 5. The nonwoven fabric according to any one of Items 1 to 4. 6. The method according to claim 1, further comprising a partial heat and pressure welding portion.
6. The nonwoven fabric according to any one of items 5 to 5. 7. Polyvinyl alcohol (A) having a degree of saponification of 90 to 99.99 mol% and a melting point Tm of 160 ° C. to 230 ° C., and (A) 100 parts by mass of alkali metal ion (B) Thermoplastic polymer (C) containing 0.00001 to 0.3 parts by mass of a thermoplastic polymer (D) having a melting point of 270 ° C. or less
When the melting point of a polymer having a higher melting point among the polymer (A) and the polymer (C) is Mp, the spinneret temperature M
After melt-spinning at a temperature of p + 10 ° C. to Mp + 80 ° C., the spun filament group is drawn and thinned by a suction / injection device, and then the opened filaments are collected and deposited on a mobile collecting conveyor device. A method for producing a nonwoven fabric, which comprises forming a fibrous web.