JPH08113860A - Production of water-resistant polyvinyl alcohol-based nonwoven fabric - Google Patents

Abstract

PURPOSE: To obtain nonwoven fabric suitable as agricultural and horticultural materials and materials related to life, having excellent strength and less fluffs, by subjecting a web of sea-island type polyvinyl alcohol-based conjugate fibers to thermal contact bonding. CONSTITUTION: A polyvinyl alcohol polymer having >=220 deg.C melting point as an island component and a water-resistant polymer such as an ethylene/vinyl acetate copolymer having <210 deg.C meting point or fusing temperature as a sea component are used to form sea-island type polyvinyl alcohol-based conjugate fibers in the weight ratio of (98:2)-(55:45). Then a web comprising the fibers is treated by a heat calendering roll having a pressure bonding face in a continuous phase and then by a heat calendering roll having a pressure bonding face in a discontinuous phase to give nonwoven fabric of thermal pressure bonding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a water resistant polyvinyl alcohol (hereinafter abbreviated as PVA) type nonwoven fabric, and more particularly to a method for producing a nonwoven fabric which improves strength and reduces fuzz.

[0002]

2. Description of the Related Art PVA-based fiber is a polyester, in terms of high strength, excellent weather resistance, water absorption, moisture absorption, heat retention, etc.
Since it has performance superior to melt-spun fibers such as polyolefin and nylon, it is manufactured as various woven and knitted fabrics and non-woven fabrics.
Widely used mainly in the field of industrial materials.

The present inventors have filed Japanese Patent Application No. 6-68543,
In Japanese Patent Application No. 5-265022, a polyvinyl alcohol-based polymer (A) having a melting point of 220 ° C. or higher and a water-resistant polymer (B) having a melting point or a fusion temperature of less than 210 ° C. are used. ) Weight ratio is 98: 2 to
55:45, wherein (A) is a sea component and (B) is an island component, and a sea-island structure polyvinyl alcohol fiber (hereinafter abbreviated as thermocompression bonding PVA fiber) is used to prepare a web, and thermocompression bonding is performed. A method for producing a PVA-based nonwoven fabric by adhering by a method is proposed.

[0004]

In order to improve the strength of the non-woven fabric, it is achieved by making the crimped portions continuous and by increasing the crimped portions. However, there is a technical upper limit to the increase in pressure-bonding area by hot pressing and thermal calendering. This means that the larger the pressure-bonding area and the wider the treatment width, the more the non-woven fabric is subjected to thermo-compression bonding, which causes unevenness of the web itself.
This is because the clearance adjustment becomes delicate due to the distortion of the metal part, which makes it difficult. Further, as the pressure-bonding area increases, and when the pressure-bonding portion is made into a continuous phase, the nonwoven fabric becomes thin and paper-like, and a thick one cannot be manufactured. On the contrary, in order to produce a thick product, it is sufficient to reduce the pressure-bonded portion to form a discontinuous phase, but the produced fabric has a large amount of fuzz. In order to reduce the fuzz, it is achieved by adding a binder resin, increasing the thermocompression bonding area, and making the pressure bonding portion continuous. However, if a binder resin is applied, a non-binder resin product cannot be produced, and the methods of increasing the thermocompression bonding area and making the pressure bonding portion continuous have the same problems as described above.

[0005]

The present invention has a melting point of 220.
A PVA-based polymer (A) having a melting point or fusion temperature of less than 210 ° C., and a weight ratio of (A) to (B) of 98: 2 to 55:45.
The present invention relates to a method for producing a non-woven fabric composed of a sea-island structure PVA-based fiber in which (A) is a sea component and (B) is an island component, and particularly to a method for improving strength and reducing fuzz. .

[0006] Specifically, the heat calender adhesion treatment is carried out by using both a pressure bonding device having a continuous pressure bonding surface and a pressure bonding device having a discontinuous pressure bonding surface. A web made of the described PVA-based sea-island structure is used at a temperature of 80 to 230 ° C., a linear pressure of 1 kg / cm or more or a surface pressure of 2 kg / cm ² or more, and the area ratio of the crimping portion is 10% to 4%.
A water-resistant PVA non-woven fabric which is thermocompression bonded 2 to 4 times by combining a crimping device having 0% and a crimping part in a continuous phase and a crimping device having a crimping part area ratio of 10 to 40% and a crimping part in a discontinuous phase Is a manufacturing method.

The PVA fiber of the present invention is disclosed in Japanese Patent Application No. 6-68.
It is a multi-component fiber having a sea-island structure as described in Japanese Patent Application No. 543 and Japanese Patent Application No. 5-265022. The PVA-based polymer (A) having a melting point of 220 ° C. or higher is a sea component. The melting point of the PVA-based polymer (A), which is the sea component, is 22
If it is less than 0 ° C, the heat resistance and water resistance of the fiber of the present invention are insufficient, and a fiber that can be used practically cannot be obtained. Also, high strength fibers cannot be obtained. It is more preferable that the melting point of the sea component PVA-based polymer (A) is 225 ° C. or higher.
There is no particular limitation on the upper limit of the melting point of the sea component polymer (A), but PVA having a melting point of 260 ° C. or higher is not common.

Specific examples of the sea component PVA polymer (A) include a polymerization degree of 500 to 24000 and a saponification degree of 99.
Highly saponified PVA of ˜100 mol%. Degree of polymerization 150
0 to 4000 and a saponification degree of 99.5 to 100 mol% are more preferable from the viewpoint of water resistance and thermocompression bonding property. In addition, ethylene, allyl alcohol, itaconic acid, acrylic acid,
Maleic anhydride and its ring-opened product, arylsulfonic acid, fatty acid vinyl ester having 4 or more carbon atoms such as vinyl pivalate, vinylpyrrolidone and 1 of the above ionic groups
Part or the total amount of P modified by a modification unit such as neutralized product
VA is also included. The amount of denaturing unit is less than 1 mol%,
It is preferably 0.5 mol% or less. The method of introducing the modifying unit is not particularly limited, whether it is copolymerization or a post reaction. The distribution of the denaturing unit is not limited to random or block. When distributed in blocks, the crystallization-inhibiting effect is small, and the high melting point can be maintained even if it is modified more than randomly. By using a high melting point PVA polymer having a high degree of saponification as a continuous phase, it is possible to obtain a performance close to that of a single fiber having a high melting point, and by using a high melting point polymer as the outermost layer of the fiber, it is possible to prevent sticking in the fiber manufacturing process. This makes it possible to prevent the occurrence of defective opening during the production of the nonwoven fabric.

A water-resistant polymer (B) having a melting point or a fusion temperature of less than 210 ° C. is used as the island component of the sea-island fiber constituting the PVA-based nonwoven fabric of the present invention. If the melting point is 210 ° C or higher, the thermocompression bonding temperature becomes too high, and the P of the sea component during thermocompression bonding is used.
It is not preferable because the orientation and crystallinity of the VA polymer (A) are easily destroyed. Even if a water-resistant amorphous polymer having no melting point is used, the amorphous polymer chip is heated to a predetermined temperature, and a pressure of 0.1 kg / cm ² is applied for 10 minutes. When the temperature is the fusion temperature, the water-resistant amorphous polymer having a fusion temperature of less than 210 ° C. is included in the water-resistant polymer (B), and the melting point of the island component water-resistant polymer (B) or the fusion temperature (hereinafter This temperature is also included in the term melting point) and is preferably 200 ° C. or lower, and more preferably 190 ° C. or lower. Furthermore, it is preferable that the difference in melting point between the sea component and the island component is 15 ° C. or more because the fiber dimensional change during thermocompression bonding becomes small. The difference in melting point is more preferably 30 ° C. or higher, and further preferably 50 ° C. or higher. Since the water-resistant polymer (B) having a melting point of less than 210 ° C. usually has low orientation and low crystallinity, it is disadvantageous when it is used as a sea component which is a matrix of fibers because it has low strength and low heat resistance. Further, when the low melting point polymer (B) is present on the outermost surface of the fiber, it easily sticks in the fiber manufacturing process, which causes a failure of opening in the nonwoven fabric manufacturing process. From this point as well, the low melting point polymer (B) needs to be an island component.

Specific examples of the water resistant polymer (B) having a melting point of less than 210 ° C. according to the present invention include ethylene / vinyl alcohol copolymer (molar composition ratio 50/50 to 20/8).
0), ethylene / vinyl acetate copolymer (molar composition ratio 9
2/8 to 20/80), polyvinyl butyral, polyvinyl formal, PVA modified with a vinyl ester of a fatty acid having 3 to 20 carbon atoms (the amount of the modifying unit is 1 mol%
Or more, preferably 2 mol% or more), modified acrylic resin, hydrocarbon elastomer such as polyisoprene,
Examples include polyurethane elastomers. Above all, in terms of heat adhesion, performance reproducibility (stability), and cost,
Ethylene / vinyl alcohol copolymer (molar composition ratio 5
PVA-based polymers of 0/50 to 20/80) and ethylene / vinyl acetate copolymer (molar composition ratio of 92/8 to 20/80) are useful as island components of fibers constituting the PVA-based nonwoven fabric of the present invention. There is no particular limitation on the degree of polymerization of the island component polymer, but it is important that the island component does not contribute to the fiber strength and contributes to the adhesiveness. 1000 is preferred. The water-resistant polymer referred to in the present invention is a solid polymer at room temperature which does not dissolve in water or hot water, preferably at a temperature of 100 ° C. or lower, and when it does not have water resistance, After being made into a non-woven fabric, when it comes into contact with water, the fixation between the fibers is released and the form of the non-woven fabric is destroyed.

The sea component / island component blending ratio [(A) / (B)] of the sea-island fiber constituting the PVA-based nonwoven fabric of the present invention is in the range of 98/2 to 55/45 by weight. If the high melting point PVA polymer (A) as a sea component is less than 55%, a high strength fiber cannot be obtained. When the high melting point PVA-based polymer (A) is less than 55% and the low melting point water resistant polymer (B) is more than 45%, the low melting point water resistant polymer (B) tends to become a sea component, resulting in sticking. Is not preferable. On the other hand, if the low-melting point water-resistant polymer (B) is less than 2%, the thermocompression bonding performance that can withstand practical use cannot be obtained. From the balance of strength, adhesion and thermocompression bonding property, the blending ratio of sea component / island component is more preferably 95/5 to 60/40, and further preferably 92/8 to 70/30.

Further, the low melting point polymer (B) which is an island component in the fibers constituting the PVA type nonwoven fabric of the present invention is not preferably present on the outermost surface of the fiber, but is preferably present near the outermost surface. The minimum thickness of the sea component near the outermost surface (closest distance to the fiber outermost surface of the low melting point polymer of the island component) is that the high melting point PVA polymer (A) on the outermost surface is broken during thermocompression bonding and the low melting point of the island component It is important for the water resistant polymer (B) to be extruded on the surface and to obtain an adhesive force. It is preferable that the island component is present within 0.01 to 2 μm from the outermost surface. The island component may be uniformly distributed in the fiber cross-sectional direction, but it is preferable to distribute it more concentratedly on the surface side. Further, the island component may be continuous in the fiber axis direction, but it is not necessarily continuous, and may be a spherical shape or an interrupted elongated rod shape or a rugby ball shape.

The sea-island fibers constituting the present invention include, in addition to the high-melting point PVA-based polymer (A) and the low-melting point water-resistant polymer (B), various stabilizers within a range that does not significantly impair the above-mentioned performance, Additives and other polymers may be added.

The shape of the sea-island fiber which constitutes the present invention is
There is no limitation as long as it can be made into a web, and specifically, long fibers or short fibers may be used.

An important point in the PVA-based nonwoven fabric of the present invention is that at least a part of the intersections and contact points of the fibers in the web of PVA-based fibers as described above are bonded by fusion. That is, in the PVA-based nonwoven fabric of the present invention, it is important that the fibers are bonded by thermocompression bonding.

Next, a method for producing the PVA-based fiber constituting the nonwoven fabric of the present invention will be described. The high melting point PVA polymer (A) and the low melting point water resistant polymer (B) are 98 /
It is dissolved in a solvent at a ratio of 2 to 55/45 to obtain a spinning dope. The solvent as used herein must be a solvent capable of dissolving at least the high melting point PVA-based polymer (A). A common solvent that also dissolves the low melting point water resistant polymer (B) is more preferable, but the high melting point P does not necessarily have to be dissolved.
It can be used if it can be pulverized and dispersed so as to be dispersed to 10 μm or less in a VA polymer solution. The dispersed particle size is preferably 5 μm or less, more preferably 1 μm or less. Even if dissolved in a common solvent for both polymers, a homogeneous transparent solution cannot be obtained depending on the compatibility of both polymers. Rather, in the spinning stock solution, the high melting point PVA-based polymer (A) becomes a matrix (sea) phase, and the low melting point water resistant polymer (B) droplets become a polymer blend solution finely dispersed in the island phase, resulting in a turbid, uniform fine particle. It is preferably a dispersed phase separation liquid. Of course, when the compatibility of both polymers is good, a uniform transparent solution is obtained, and the stock solution and spinning conditions may be set so that the high melting point polymer (A) becomes a sea component during fiber formation.

Next, the obtained stock solution is subjected to dry spinning, dry wet spinning or wet spinning. In dry spinning, the spinning and drawing conditions are selected so that the high melting point polymer (A) becomes a matrix (sea component) and the low melting point polymer (B) becomes islands while the solvent evaporates, and the obtained fiber is wound up. In dry-wet spinning, the stock solution is once discharged from a nozzle into an inert gas phase,
Then, the mixture is passed through a solidifying solution to solidify and extract the solvent of the stock solution, and then subjected to wet stretching and dry heat stretching and winding. Alternatively, in wet spinning, the stock solution is directly discharged from a nozzle into a solidifying solution, solidified and extracted, wet-stretched and dry-heat stretched and wound up. In either spinning method, it is necessary to consider the stock solution and spinning conditions so that the high melting point polymer (A) becomes the sea component and the low melting point polymer (B) becomes the island component.

Next, a method for producing the nonwoven fabric of the present invention from such PVA type fibers will be described. The web forming method is not particularly limited. For example, the fibers are crimp-cut into staples and subjected to a card or random webber to obtain a short fiber web. No. 125648, that is, an air gun consisting of multiple spindles for injecting an opened fiber bundle together with a compressed air stream and side guns for injecting only a compressed air stream at both ends thereof are arranged in a line, and four sides are provided downstream thereof. A hood surrounded by a flat plate and adjusted so that its slit width is narrowed from the inlet to the outlet is arranged, and a non-twisted fiber bundle is injected and passed together with the compressed air flow from the air gun into the hood. , By the method of collecting on the moving collecting conveyor so that the spread filaments from the adjacent air guns are entangled with each other, the variation of the basis weight is small in the width direction. There is a method such as obtaining a have long fiber web. Needless to say, fibers other than the above-mentioned PVA-based fibers can be added during web-making within a range that does not significantly impair the effects of the present invention.

Next, the web is thermocompression-bonded at a temperature of 80 to 230 ° C.
Also, in a thermocompression bonding apparatus in which the area of one pressure bonding part is 10 to 40% at a linear pressure of 1 kg / cm or a surface pressure of 2 kg / cm ² or more, the pressure bonding part (that is, the pattern of the pressure bonding part) becomes a continuous phase. The web is adhered by thermocompression bonding 2 to 4 times with a combination of a pressure-bonding roll or pressure-bonding plate and a pressure-bonding roll or pressure-bonding plate having a pressure-bonding portion in a discontinuous phase. Temperature 80
Less than ℃, linear pressure less than 1kg / cm or surface pressure 2kg / cm
^When it is less than ² , the high melting point polymer (A) on the outermost surface is not broken and the low melting point water resistant polymer (B) as an island component is not extruded onto the fiber surface, resulting in low adhesive strength. By heating the high melting point polymer (A) on the outermost surface and applying pressure in a softened state, the polymer phase on the outermost surface is broken, and the low melting point polymer (B) as an adhesive component near the surface is extruded and adheres. It becomes possible. If the thermocompression bonding temperature is too high, the molecular orientation and crystals of the sea component may break, and the shrinkage during thermocompression bonding is large, and the web after thermocompression bonding becomes hard,
Should not be above 230 ° C. The appropriate thermocompression bonding temperature varies depending on the sea / island polymer specifications, distribution state, applied pressure, etc., but is preferably 150 to 230 ° C, and 180 to 2
More preferably, it is 20 ° C.

If the applied pressure is too high, the fiber structure of the sea component will be destroyed more than necessary, which is not preferable. The linear pressure applied by a thermal calendar roller or the like is preferably 500 kg / cm or less. The linear pressure is more preferably 200 kg / cm or less, further preferably 100 kg / cm or less. The surface pressure by hot pressing or the like is preferably 1000 kg / cm ² or less. The surface pressure is more preferably 400 kg / cm ² or less, and further preferably 200 kg / cm ² or less. Usually, it is used at a linear pressure of 5 to 50 kg / cm or a surface pressure of 10 to 100 kg / cm ² .

The area of one-time pressure bonding is preferably 10 to 40%. If it is less than 10%, the crimping area is too small and the total crimping area is increased, so that the number of thermocompression bonding treatments is increased and the fiber structure is destroyed more than necessary, and an extra thermocompression bonding treatment device is required. Therefore, it is not preferable in terms of cost. When the pressure-bonding area is larger than 40%, only a thin cloth is obtained and cloths having various thicknesses cannot be obtained, which is not preferable. Further, the clearance adjustment becomes delicate due to unevenness of the web itself, distortion of the metal portion, etc., which makes it difficult. Therefore, 10 to 40% is preferable for one crimping area.
5 to 25% is more preferable.

Thermocompression bonding has a minimum of 1 when the pressure bonding portion is a continuous phase.
It is important to process once and at least once with a discontinuous phase. The treatment with the continuous phase is performed mainly for the purpose of reducing fuzz and improving the fabric strength, and the treatment with the discontinuous phase is performed for the purpose of sufficiently adhering. for that reason,
It is not necessary to perform thermocompression bonding sufficiently, and thermocompression treatment temperature is 80 to 18
0 ° C, linear pressure 1-50 kg / cm or surface pressure 2-100
Perform at kg / cm ² . If only the treatment with the continuous phase is carried out until the cloth is sufficiently adhered, only the thin cloth can be produced. Further, even if only the treatment with the discontinuous phase is performed, even if the pressure-bonded portion is sufficiently adhered, the adhered portion is discontinuous, so that the cloth strength is low and fuzz is large. From the above, in order to obtain a thick cloth with less fluffing, it is important to treat the pressure-bonded portion with a combination of a continuous phase and a discontinuous phase. The order of the treatment with the continuous pressure portion and the treatment with the non-continuous pressure portion does not matter, and either of them may be performed first or later. As a pressure bonding device having a continuous pressure bonding portion, a pressure bonding roll or pressure bonding plate having a pressure bonding portion area of 10 to 40% in which independent non-pressure bonding portions having an area of 0.2 to ²⁰ mm ² are uniformly dispersed is preferable. As the pressure-bonding device having a discontinuous phase portion, a pressure-bonding roll or pressure-bonding plate having a pressure-bonding portion area of 10 to 40% in which independent pressure-bonding portions having an area of 0.2 to 50 mm ² are uniformly dispersed is preferable.

In the present invention, it is preferable that the portion which is not substantially thermocompression-bonded is 30 to 80%. 80%
If it is more than that, the target fabric cannot be produced due to a large amount of fuzz, and if it is less than 30%, the produced fabric can be either a thin fabric or a fabric not sufficiently adhered. From these things, it is necessary that the portion which is not thermocompression bonded is 30 to 80%, and more preferably 60 to 80%.

Temperature 180 ° C to 230 ° C, linear pressure 5 kg / c
When the thermocompression bonding treatment is performed under m or a surface pressure of 10 kg / cm ² or more, that portion becomes transparent. Therefore, in order to improve the light transmittance of the cloth, the treatment under the above-mentioned conditions is performed in the case of the treatment with the discontinuous phase. The light transmittance can also be increased by performing thermocompression bonding and increasing the number of bonded portions. As a method for increasing the number of bonded portions, it is possible to use a material having a large pressure bonding area and increase the number of treatments. When the nonwoven fabric of the present invention is used for agricultural purposes and the like, a particularly high light transmittance is a very important factor.

If the number of treatments is 5 or more, the fiber structure is destroyed more than necessary, which is not preferable. From this, the number of times of thermocompression bonding is preferably 2 to 4 times, and more preferably 2 to 3 times. Further, the thermocompression bonding treatment may be carried out continuously or may be carried out once at a time.

The thermocompression bonding time can be as short as 0.01 to 10 seconds or so. The ability to bond in a short time is a very important property of the thermocompression bonding method. In the case of the above fibers, if the thermocompression bonding time is 10 minutes or more, the adhesive force tends to decrease rather. The cause of this is unknown, but it is presumed to be related to crystallization of the polymer. Therefore, the linear pressure application type calender roll method having a shorter treatment time can be more preferably used for thermocompression bonding than the surface pressure application type hot press method having a long treatment time.

The basis weight of the PVA fiber web is 20 to 150.
g / cm ² is preferred. If it is less than 20 g / cm ^2, the purpose of obtaining a thick cloth will be lost. 150 g / c
If it is larger than m ² , the web is too thick and it becomes difficult to perform the thermocompression treatment in the entire thickness direction. Therefore, the basis weight of the PVA-based fiber web is preferably ²⁰ to 150 g / cm ² ,
It is more preferably 30 to 100 g / cm ² .

The definition of the parameter and the measuring method thereof in the present invention are as follows. 1. Melting point In the case of a crystalline polymer, a differential scanning calorimeter (DSC-20) manufactured by METTLER CORPORATION was used, and the sample polymer was placed under nitrogen at 20
When the temperature is raised at a rate of ° C / min, the temperature showing an endothermic peak is measured.

2. Fusing temperature In the case of an amorphous polymer, when the polymer chips are placed in a hot air dryer at a specified temperature and a pressure of 0.1 kg / cm ² is applied for 10 minutes, the chips melt to the extent that the boundaries between the chips cannot be determined. Measure the lowest temperature to wear.

3. Water resistance A property that does not dissolve even if immersed in 80 ° C water for 1 hour.

4. Evaluation of fluff The cloth was lightly rubbed with the belly of the thumb, forefinger and middle finger of the hand, ⊚ indicates that no fluff was present, and x indicates that the thread was loosely scattered.

[0032]

EXAMPLES The present invention will now be described with reference to examples, but the present invention is not limited to these examples. In Examples,% is a value based on weight unless otherwise specified. The strength and elongation of the fibers in Examples and Comparative Examples were measured with an Instron tensile tester at a sample gripping interval of 10 cm and a tensile speed of 5 cm / min. The strength and elongation of the non-woven fabric were measured under the same conditions except that the sample gripping width was 2.5 cm with an Instron tensile tester as in the case of the fiber. The tear strength was measured by the single tongue method. Table 1 shows the basis weights, thicknesses, strengths, elongations, values of tear strength, and fuzz evaluations of the nonwoven fabrics in Examples and Comparative Examples.

Example 1 Polymerization degree 2400, saponification degree 99.8 mol%, melting point 235
C. PVA as the polymer (A), the degree of polymerization is 750, and the fusion temperature is 50 ° C. or less ethylene / vinyl acetate = 32/68
(Mole ratio) The copolymer (35% methanol solution) is used as the polymer (B), and the blending ratio of the high melting point PVA polymer (A) / low melting point water resistant polymer (B) is 90/10, and the total polymer concentration is Dimethylsulfoxide (hereinafter abbreviated as DMSO) at 90 ° C under nitrogen so that the ratio becomes 20%.
It was dissolved by heating with stirring. The resulting blended solution was fairly turbid, but showed no tendency to aggregate phase separation.

This spinning dope was prepared with a hole diameter of 0.12 mm and a number of holes of 8
70% methanol and 30% DMSO through the No. 0 nozzle
Was wet-spun in a solidifying solution at 3 ° C. The obtained solidified Itoshino was cloudy, and it was presumed that both polymers were phase-separated. At this time, no special turbidity was generated in the solidified liquid. This solidified yarn is wet-stretched by 5.0 times, immersed in a methanol solution to extract and wash DMSO in the solidified yarn, apply a mineral oil-based oil agent, dry at 100 ° C, and then fully stretch at 220 ° C. It was stretched by dry heat so that the magnification was 14 times. The obtained 240 dr / 80f filament had no sticking, and the melting temperature in water was 128 ° C, and the water resistance was good. The single yarn strength was 15.7 g / dr. In addition, from cross-section observation, it is a circular cross-section, high melting point PVA (A) is a sea component, low melting point ethylene / vinyl acetate copolymer (B)
Is an island component, and at least 100 islands are present, and it was found that many island components were present within 1 μ of the outermost surface.

The PVA-based filament fiber web having a basis weight of 50 g / m ² is obtained by once winding the obtained PVA-based fiber without twisting, and then opening and collecting it by the above-mentioned method proposed in JP-A-5-125648. made. Then, this was subjected to a calender roll treatment once with a crimping area of 20%, a continuous phase roll (FIG. 1), a roll temperature of 110 ° C., a roll linear pressure of 33 kg / cm, and a treatment speed of 3 m / min. With a roll that is not in the continuous phase (FIG. 2), the web was adhered by performing the calender roll treatment once at a roll temperature of 220 ° C., a roll linear pressure of 33 kg / cm, and a treatment speed of 5 m / min. 68% of the parts were not thermocompression bonded. The web at this time was not broken into single yarn or fluffed even if it was rubbed by hand. The average horizontal breaking length of the web was 6.6 km and the thickness was 0.309 mm. The embossed pattern of FIG. 1 is a weave pattern, and the height difference between the deepest part of the concave part and the highest part of the convex part is 0.42 mm, and the size of the concave part is 1.5 mm in major axis and O. It is 8 mm. In the embossed pattern of FIG. 2, the height difference is 0.55 mm, and the size of the convex portion is 0.78 mm × 1.141 mm at the top and 1.414 m at the bottom.
It is m × 1.775 mm.

Example 2 A short fiber web having a basis weight of 50 g / m ² was obtained in the same manner as in Example 1, and then this was crimped with an area of 20%, a continuous phase roll (FIG. 1) was used, the roll temperature was 130 ° C., and the roll linear pressure was 33 kg. / C
m, processing speed of 3 m / min 1 calender roll processing
Repeatedly, followed by a pressure bonding area of 15%, a roll that is not in continuous phase (Fig. 2), a roll temperature of 220 ° C, and a roll linear pressure of 33 kg.
/ Cm and a processing speed of 5 m / min, the calender roll treatment was performed once to bond the webs. 68% of the portion is not thermocompression bonded. The web at this time was not broken into single yarn or fluffed even if it was rubbed by hand. The average vertical breaking length of the web is 7.6km and the thickness is 0.272m.
It became m.

Example 3 A short fiber web having a basis weight of 50 g / m ² was obtained in the same manner as in Example 1, and then this was crimped with an area of 20%, a continuous phase roll (FIG. 1) was used, the roll temperature was 150 ° C., and the roll linear pressure was 33 kg. / C
m, processing speed of 3 m / min 1 calender roll processing
Repeatedly, followed by a pressure bonding area of 15%, a roll that is not in continuous phase (Fig. 2), a roll temperature of 220 ° C, and a roll linear pressure of 33 kg.
/ Cm and a processing speed of 5 m / min, the calender roll treatment was performed once to bond the webs. 68% of the portion is not thermocompression bonded. The web at this time was not broken into single yarn or fluffed even if it was rubbed by hand. The average vertical breaking length of the web is 7.8km and the thickness is 0.250m.
It became m.

Comparative Example 1 A short fiber web having a basis weight of 50 g / m ² was obtained in the same manner as in Example 1, and then this was bonded with a pressing area of 20% and a continuous phase roll (FIG. 1) at a roll temperature of 150 ° C. and a roll linear pressure of 33 kg. / C
m, processing speed of 3 m / min 1 calender roll processing
The web was glued back in. When the web at this time was rubbed by hand, it did not break up into single yarn or fluff. The average vertical breaking length of the web is 3.5km and the thickness is 0.329m.
It became m. Since the thermocompression bonding process is performed weakly, it is thick and has little fuzz but weak strength.

Comparative Example 2 A short fiber web having a basis weight of 50 g / m ² was obtained in the same manner as in Example 1, and then this was crimped with an area of 20%, a continuous phase roll (FIG. 1) was used, the roll temperature was 220 ° C., and the roll linear pressure was 33 kg. / C
m, processing speed of 3 m / min 1 calender roll processing
The web was glued back in. The web at this time was not broken into single yarn or fluffed even if it was rubbed by hand.
The average vertical breaking length of the web is 8.3 km and the thickness is 0.
It became 211 mm. The calender roll was a continuous phase and strongly subjected to thermocompression bonding, so that it was thin and paper-like with little fuzz and strong strength.

Comparative Example 3 A short fiber web having a basis weight of 50 g / m ² was obtained in the same manner as in Example 1, and then this was bonded with a pressing area of 15% and the roll temperature was 220 ° C. with a roll not in continuous phase (FIG. 2) and a roll linear pressure. 33 kg
/ Cm and a processing speed of 5 m / min, the calender roll treatment was performed once to bond the webs. When the web at this time was rubbed by hand, it was found that the web was broken into single yarns or fluffed. The average vertical breaking length of the web is 4.4km and the thickness is 0.3.
It became 76 mm. Since the calender roll is in a discontinuous phase, it is thick but has a lot of fuzz and weak strength.

[0041]

[Table 1]

[0042]

EFFECT OF THE INVENTION Polyvinyl alcohol polymer (A) having a melting point of 220 ° C. or higher and a melting point or a fusion temperature of 2
Comprising a water resistant polymer (B) having a temperature of less than 10 ° C.,
The weight ratio of (A) and (B) is in the range of 98: 2 to 55:45, (A) is a sea component, and (B) is an island component. At least a part of the intersection points and contact points can be bonded by thermocompression bonding, and at the time of bonding, the strength of the non-woven fabric is improved and the fluffiness is improved by performing a thermal calendar bonding process in which a device having a continuous phase and a device having a discontinuous pressure bonding part are combined. It has become possible to manufacture reduced nonwoven fabrics. The non-woven fabric obtained by the present invention can be suitably used as an agricultural and horticultural material as a covering material, a house lining curtain, a heat shield material, and a windshield material. Also,
It is also suitable for use in kitchen laundry and wipers for life related materials.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a surface handle of a thermocompression bonding roll in which a pressure bonding portion is a continuous phase.

FIG. 2 is a diagram showing an example of a surface handle of a thermocompression bonding roll in which a pressure bonding portion is in a discontinuous phase.

[Explanation of symbols]

 a concave part b convex part

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Claims (1)

[Claims] 1. A polyvinyl alcohol-based polymer (A) having a melting point of 220 ° C. or higher and a melting point or fusion temperature of 2
Comprising a water resistant polymer (B) having a temperature of less than 10 ° C.,
The weight ratio of (A) and (B) is in the range of 98: 2 to 55:45, (A) is a sea component, and (B) is an island component. When fixing the fibers to make a non-woven fabric,
A method for producing a non-woven fabric, which comprises performing a thermal calender adhesion treatment by using a crimping device having a continuous crimping surface and a crimping device having a discontinuous crimping surface.