JP7396535B1 - Nonwoven fabric roll and its manufacturing method - Google Patents

Abstract

The present invention provides a nonwoven fabric roll that has sufficient mechanical strength and dimensional stability, and also has excellent film coating processability using a wide-width die coating method.
The nonwoven fabric roll of the present invention is a nonwoven fabric roll formed by winding up a long fiber nonwoven fabric made of fibers containing a thermoplastic resin as a main component, and the apparent density of the long fiber nonwoven fabric is 0.70 g/cm ³ The nonwoven fabric roll has a winding hardness of 35.0g or more and ^50.0g or less, and a hardness difference in the roll width direction of 7.0g or more and 20.0g or less. It is.

Description

The present invention relates to a nonwoven fabric roll and a method for manufacturing the same.

In recent years, membrane technology has been applied in many cases to water treatment, and separation membranes are used for water treatment at water purification plants, seawater desalination, and other applications.

In semipermeable membranes such as reverse osmosis membranes used for desalination of seawater, flat membranes integrated with a support such as nonwoven fabric or woven fabric are used. Reverse osmosis membranes are manufactured by casting a solution of a high molecular weight polymer onto a support such as nonwoven fabric or woven fabric to form a support layer, and then forming a semipermeable membrane on the support layer. .

In the process of forming this support layer, there is a comma coating method in which the cast resin solution is pooled between a roller with a blade and the support, and the excess resin solution is scraped off with the blade, and the role of the mold. An example of this method is a die coating method in which a resin solution is applied to a support by bringing a die in contact with the support. In the comma coat method, if there is a foreign object or protrusion between the blade portion and the support, the support will break and the process passability will deteriorate, so forming the support layer by the die coat method has been preferred.

In addition, when forming a support layer, when a solution of a high molecular weight polymer is cast or coated on a nonwoven fabric or woven fabric that serves as the support, it may bleed through due to excessive penetration, or the membrane material may peel off. In addition, excellent film forming properties are required that do not cause defects such as non-uniformity of the film or pinholes due to fuzzing of the support.

Reverse osmosis membranes used for seawater desalination etc. may be operated continuously at a constant operating pressure, or may be operated by varying the operating pressure in response to changes in the quality and temperature of the supplied seawater, fluctuations in the amount of fresh water produced, etc.

For this reason, supports such as nonwoven fabrics and woven fabrics are required to have high mechanical strength, high dimensional stability, and membrane peel strength, so supports made of long fiber nonwoven fabrics made of continuous thermoplastic filaments have been proposed. (See Patent Document 1.)

In addition, in a semipermeable membrane support made of nonwoven fabric for forming a membrane by the comma coat method, the nonwoven fabric has a low density layer with an air permeability of 5 to 50 cc/cm ² /sec and a layer with an air permeability of 0.1 cc/cm 2 /sec. /cm ² /sec or more and less than 5cc/cm ² /sec, and the nonwoven fabric has a two-layer structure in which a high density layer is laminated and integrated, and the air permeability of the entire nonwoven fabric is 0.1 to 4.5cc/cm ² /sec. A semipermeable membrane support has been proposed (see Patent Document 2).

International Publication No. 2009/017086 Japan Special Publication No. 5-35009

However, since the technology disclosed in Patent Document 1 uses a support made of a long fiber nonwoven fabric made of continuous filaments, the die coating method that applies a uniform film has drawbacks due to variations in the thickness of the support, and the nonwoven fabric roll When this happens, the variation becomes more obvious, causing problems such as poor film formation and wrinkles.

Further, the technology disclosed in Patent Document 2 is a nonwoven fabric made of short fibers instead of continuous filaments, and there is a risk that the film may become uneven and defects may occur due to fluffing. Furthermore, there has been no improvement in the strength of the nonwoven fabric that is the support, and sufficient mechanical strength and dimensional stability have not been obtained as a support.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a nonwoven fabric roll made of a long fiber nonwoven fabric, which has sufficient mechanical strength and dimensional stability, and is also excellent in film coating processability using a wide die coating method.

The present invention aims to solve the above problems, and according to the present invention, the following inventions are provided.

[1] A nonwoven fabric roll obtained by winding up a long fiber nonwoven fabric made of fibers containing a thermoplastic resin as a main component, wherein the apparent density of the long fiber nonwoven fabric is 0.70 g/cm ³ or more. 90 g/cm ³ or less, the winding hardness of the nonwoven fabric roll is 35.0 g or more and 50.0 g or less, and the hardness difference in the roll width direction is 7.0 g or more and 20.0 g or less.

[2] The nonwoven fabric roll has a winding length of 100 m or more and 20,500 m or less, and the difference between the thickness of the long fiber nonwoven fabric in the outer layer of the roll and the thickness of the long fiber nonwoven fabric in the inner layer of the roll is 0.010 mm or less, [1] The nonwoven fabric roll described in ].

[3] The nonwoven fabric roll according to [1] or [2], wherein the nonwoven fabric roll has a roll width of 0.5 m or more and 1.5 m or less.

[4] The nonwoven fabric roll according to any one of [1] to [3], wherein the long fiber nonwoven fabric has a smoothness of 10 seconds or more and 60 seconds or less on both surfaces.

[5] The nonwoven fabric roll according to any one of [1] to [4] above, wherein the thermoplastic resin is a polyester resin.

[6] A method for manufacturing a nonwoven fabric roll, which sequentially performs the following steps a to d.
( Step a) After obtaining long fibers by spinning the thermoplastic resin from a spinneret ( 1 ) having discharge holes,
applying gas to the long fibers through a cooling section ( 2 ) in a direction perpendicular to the running direction of the long fibers;
Next, after applying gas to the long fibers through the gas supply section ( 3 ) in a direction perpendicular to the running direction of the long fibers,
The long fibers are passed through an intake/exhaust section ( 4 ) with a length of 1 mm or more and 150 mm or less, which is provided directly below the gas supply section ( 3 ) , and are suction-drawn at a spinning speed of 3000 m/min or more and 5500 m/min or less. Step ( step b) of collecting the stretched long fibers on a moving net conveyor ( 6 ) to form a fiber web ( 9 ) ( step c) The step of collecting the drawn long fibers on a moving net conveyor (6) to form a fiber web ( 9 ) . The nonwoven fabric sheet ( 10 ) ( Step d) Layering two or more layers of the nonwoven fabric sheets, using a pair of flat rolls in which at least one roll surface temperature is higher than the roll surface temperature in Step c by 20° C. or more and 100° C. or less, A step of obtaining a long fiber nonwoven fabric by thermocompression bonding with a linear pressure of 500 N/cm or more and 5000 N/cm or less, and then winding up the long fiber nonwoven fabric to obtain a nonwoven fabric roll [7] The method for producing a nonwoven fabric roll according to item [6], wherein in step a', the melting point of the thermoplastic resin in step c is the melting point of the low melting point polymer.
( Step a') A high melting point polymer and a low melting point polymer having a melting point lower than the melting point of the high melting point polymer by 10° C. or more and 110° C. or less are spun from a composite spinneret ( 1 ) having a discharge hole. ,
After obtaining long fibers covered with a low melting point polymer without exposing the high melting point polymer,
applying gas to the long fibers through a cooling section ( 2 ) in a direction perpendicular to the running direction of the long fibers;
Next, after applying gas to the long fibers through the gas supply section ( 3 ) in a direction perpendicular to the running direction of the long fibers,
The long fibers are passed through an intake/exhaust part ( 4 ) with a length of 1 mm or more and 150 mm or less, which is provided directly below the gas supply part ( 3 ) ,
[8] The thermoplastic resin in step a is a polyester resin, or the high melting point polymer and/or the low melting point polymer in step a'. The method for producing a nonwoven fabric roll according to [6] or [7] above, wherein is a polyester resin.

[9] In step d, the nonwoven fabric sheets obtained by dividing the nonwoven fabric sheet obtained in step c in the width direction are stacked so as to satisfy the following formula 1, and bonded under heat to form a long fiber nonwoven fabric. The method for producing a nonwoven fabric roll according to any one of [6] to [8] above, wherein the long fiber nonwoven fabric is obtained by winding up the long fiber nonwoven fabric to obtain a nonwoven fabric roll.

0.90≦W _Min /W _Max ≦1.00 (1)
Here, in the width direction of the stacked nonwoven fabric sheets, the maximum basis weight W _Max (g/m ² ) and the minimum basis weight W _Min (g/m ² ) are assumed.

[10] The long fiber nonwoven fabric has an apparent density of 0.70 g/cm ³ or more and 0.90 g/cm ³ or less, and the winding hardness of the nonwoven fabric roll is 35.0 g or more and 50.0 g or less, and the roll width direction The method for producing a nonwoven fabric roll according to any one of [6] to [9] above, wherein the hardness difference is 7.0 g or more and 20.0 g or less.

According to the present invention, it is possible to provide a nonwoven fabric roll that has sufficient mechanical strength and dimensional stability when used as a separation membrane support, and also has excellent membrane coating processability using a wide die coating method. .

FIG. 1 is a schematic diagram of a manufacturing apparatus for spinning a thermoplastic resin from a spinneret to obtain a nonwoven fabric sheet according to the method for manufacturing a nonwoven fabric roll of the present invention.

A nonwoven fabric roll according to an embodiment of the present invention is a nonwoven fabric roll formed by winding up a long fiber nonwoven fabric made of fibers containing a thermoplastic resin as a main component, and wherein the long fiber nonwoven fabric has an apparent density of 0. 70 g/cm ³ or more and 0.90 g/cm ³ or less, the winding hardness of the nonwoven fabric roll is 35.0 g or more and 50.0 g or less, and the hardness difference in the width direction is 7.0 g or more and 20.0 g or less. It's a roll. The components will be explained in detail below, but the present invention is not limited to the scope described below unless it goes beyond the gist of the invention, and various modifications may be made without departing from the gist of the invention. Changes are possible.

(Thermoplastic resin)
The nonwoven fabric roll of one embodiment of the present invention is formed by winding up a long fiber nonwoven fabric made of fibers containing a thermoplastic resin as a main component.

Examples of the above-mentioned thermoplastic resin include polyester, polyamide, polyolefin, and mixtures and copolymers thereof. Among them, polyester is preferable because it has excellent mechanical strength and durability such as heat resistance, water resistance, and chemical resistance.

Polyester consists of an acid component and an alcohol component. As the acid component, aromatic carboxylic acids such as terephthalic acid, isophthalic acid, and phthalic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexanecarboxylic acid can be used. As the alcohol component, ethylene glycol, diethylene glycol, polyethylene glycol, etc. can be used.

Examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate, and copolymers thereof.

(Fiber whose main component is thermoplastic resin)
A crystal nucleating agent, a matting agent, a lubricant, a pigment, an antifungal agent, an antibacterial agent, a flame retardant, a hydrophilic agent, and the like may be added to the fiber containing the thermoplastic resin as a main component. In particular, during thermocompression molding of long fiber nonwoven fabrics, metal oxides such as titanium oxide, which have the effect of improving the adhesion of long fiber nonwoven fabrics by increasing thermal conductivity, and mold releasability between the thermocompression roll and the fiber web are used. It is preferable to add an aliphatic bisamide such as ethylene bisstearamide and/or an alkyl-substituted aliphatic monoamide, which has the effect of improving adhesive stability by increasing the adhesion stability. These various additives may be present in the thermoplastic fiber or on the surface of the thermoplastic fiber.

Further, the cross-sectional shape of the fibers containing thermoplastic resin as a main component includes circular, flat, polygonal, multilobal shapes such as X-shape and Y-shape, and hollow shapes.

Further, it is also preferable that the fiber containing the thermoplastic resin as a main component is a composite fiber.

The composite fiber is preferably a composite fiber in which a high melting point polymer is surrounded by a low melting point polymer having a melting point lower than that of the high melting point polymer.

By making such a composite fiber, the thermoplastic continuous fibers will firmly adhere within the nonwoven fabric when bonded under heat and pressure, and surface smoothness can be obtained. Non-uniformity during casting of the polymer solution and membrane defects can be suppressed.

In addition, by using such composite fibers, the long fiber webs that make up the nonwoven fabric can firmly adhere to each other, and the number of bonding points in the nonwoven fabric is greater than when fibers with different melting points are mixed together. This leads to improved dimensional stability and durability when used as a support, especially as a semipermeable membrane support to which high pressure is applied during use.

The main component here refers to a component that accounts for 50% by mass or more of the components of the composite fiber.

The difference in melting point between the above-mentioned high melting point polymer and low melting point polymer is preferably 10°C or more and 110°C or less. By setting the difference in melting point to 10°C or more, more preferably 20°C or more, even more preferably 30°C or more, desired thermal adhesiveness can be obtained. In addition, by setting the temperature to 110°C or lower, more preferably 100°C or lower, and still more preferably 90°C or lower, it is possible to suppress the low melting point polymer component from being fused to the thermocompression roll during thermocompression bonding, thereby reducing productivity. I can do it.

Further, the melting point of the high melting point polymer in the composite fiber is preferably 160°C or more and 320°C or less. By setting the temperature to 160° C. or higher, more preferably 170° C. or higher, and still more preferably 180° C. or higher, the shape stability is excellent even in processing steps where heat is applied. In addition, by setting the temperature to 320°C or lower, more preferably 300°C or lower, and even more preferably 280°C or lower, it is possible to suppress the consumption of a large amount of thermal energy for melting during the production of long fiber nonwoven fabric, which reduces productivity. I can do it.

On the other hand, the melting point of the low melting point polymer in the composite fiber is preferably 150° C. or higher and 310° C. or lower, while ensuring a difference in melting point between the high melting point polymer and the low melting point polymer. By setting the temperature to 150° C. or higher, more preferably 160° C. or higher, and still more preferably 170° C. or higher, the shape stability is excellent even in processing steps where heat is applied. In addition, by setting the temperature to 310°C or lower, more preferably 290°C or lower, and still more preferably 270°C or lower, it is possible to suppress the consumption of a large amount of thermal energy for melting during the production of long fiber nonwoven fabric, which reduces productivity. I can do it.

Specific examples of such a combination of a high melting point polymer and a low melting point polymer (high melting point polymer/low melting point polymer) include polyethylene terephthalate/polybutylene terephthalate, polyethylene terephthalate/polytrimethylene terephthalate, polyethylene terephthalate/polylactic acid, Examples include polyethylene terephthalate/copolymerized polyethylene terephthalate. Isophthalic acid and the like are preferred as the copolymerization component of the copolymerized polyethylene terephthalate.

In addition, in the present invention, the melting point of the thermoplastic resin shall be a value measured as follows.
(1) Using a differential scanning calorimeter, perform one measurement under the following conditions. As the differential scanning calorimeter, for example, "Q100" manufactured by TA Instruments is used.
・Measurement atmosphere: Nitrogen flow (150mL/min)
・Temperature range: 30-350℃
・Heating rate: 20℃/min ・Sample amount: 5mg
(2) Calculate the average value of the endothermic peak apex temperature and use it as the melting point of the measurement target. However, if there are multiple endothermic peaks in the resin before fiber formation, the peak apex temperature on the highest temperature side is used. Furthermore, when fibers are to be measured, the measurement is performed in the same manner, and the melting point of each component is estimated from a plurality of endothermic peaks. In this case, the endothermic peak due to the composite fiber is the endothermic peak (A) on the highest temperature side, the endothermic peak that appears on the side with a shorter elapsed time (the side where the peak appears earlier), and the endothermic peak that appears next to the endothermic peak on the highest temperature side. It is a peak group showing a high peak (endothermic peak (B)), and the endothermic peak (A) indicates the melting point of the high melting point polymer, whereas the endothermic peak (B) above indicates the melting point of the low melting point polymer. It indicates the melting point.

The proportion of the low melting point polymer in such a composite fiber is preferably 10% by mass or more and 70% by mass or less in the composite fiber. By setting the content to 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more, desired thermal adhesiveness can be obtained. In addition, by setting the content to 70% by mass or less, more preferably 60% by mass or less, and still more preferably 50% by mass or less, the low melting point polymer component is fused to the thermocompression roll during thermocompression bonding, thereby reducing productivity. Can be suppressed.

Examples of the composite form of such a composite fiber include a concentric core-sheath type, an eccentric core-sheath type, and an island-in-the-sea type. Among these, a concentric core-sheath type, particularly an embodiment in which a low melting point polymer is used as the sheath component, is preferred in that the fibers can be firmly adhered to each other by thermocompression bonding. When the composite fiber has an irregular cross-sectional shape, it is preferable that the low melting point polymer component exists near the outer periphery of the fiber cross section so that it can contribute to thermocompression bonding.

Moreover, when using the above-mentioned composite fiber, its cross-sectional shape is particularly preferably circular. By doing so, the fibers can be uniformly and firmly fused together, resulting in a long fiber nonwoven fabric with excellent mechanical strength.

It is preferable that the average single fiber diameter of the fibers mainly composed of the above-mentioned thermoplastic resin is 3 μm or more and 17 μm or less. By setting the average single fiber diameter to preferably 3 μm or more, more preferably 7 μm or more, and even more preferably 10 μm or more, spinnability is less likely to decrease during the production of a long fiber nonwoven fabric, and the breathability of the support can be maintained. Therefore, it is possible to obtain good film forming properties with less peeling of the film during casting of the high molecular weight polymer solution.

On the other hand, by setting the average single fiber diameter to preferably 17 μm or less, more preferably 15 μm or less, and even more preferably 14 μm or less, a long fiber nonwoven fabric and support with excellent uniformity can be obtained, and the support Since it is possible to increase the density of the polymer solution, it is possible to obtain good film forming properties with less excessive permeation during casting of the high molecular weight polymer solution.

Note that the average single fiber diameter (μm) of the fibers whose main component is the thermoplastic resin is a value calculated by the following procedure.
(1) Ten small samples (100 mm x 100 mm) are randomly taken from the long fiber nonwoven fabric.
(2) Take a surface photograph with a microscope (for example, "VHX-D500" manufactured by Keyence Corporation) at a magnification of 500 times or more and 3,000 times or less, and measure the diameter of a total of 100 single fibers, 10 from each sample. .
(3) Calculate the average single fiber diameter (μm) by rounding off the arithmetic mean value of the 100 measured values to the first decimal place.

(Long fiber nonwoven fabric)
The apparent density of the long fiber nonwoven fabric in one embodiment of the present invention is 0.70 g/cm ³ or more and 0.90 g/cm ³ or less. By setting the apparent density of the long-fiber nonwoven fabric to 0.70 g/cm ³ or more, preferably 0.75 g/cm ³ or more, and more preferably 0.80 g/cm ³ or more, excessive penetration during polymer solution casting can be prevented. It is possible to obtain a separation membrane that has good film formability with a small amount of carbon dioxide, has high peel strength and mechanical strength, and is excellent in durability. On the other hand, by setting the apparent density of the long fiber nonwoven fabric to 0.90 g/cm ³ or less, preferably 0.88/cm ³ or less, more preferably 0.85 g/cm ³ or less, it is possible to provide a support during polymer solution casting. It is possible to obtain a separation membrane that quickly penetrates into the interior, adheres firmly, and has excellent membrane peel strength.

Note that the apparent density (g/cm ³ ) of the long fiber nonwoven fabric is calculated by the following procedure.
(1) Use the value calculated by converting the unit weight (g/m ² ) of the long fiber nonwoven fabric from the thickness (mm) of the long fiber nonwoven fabric and rounding the result to the third decimal place. shall be taken as a thing.

The basis weight and thickness of the long fiber nonwoven fabric are calculated by the procedure described below.

The long fiber nonwoven fabric preferably has a basis weight of 20 g/m ² or more and 150 g/m ² . By setting the basis weight to preferably 20 g/m ² or more, more preferably 30 g/m ² or more, and even more preferably 40 g/m ² or more, good film formability can be obtained with less excessive penetration during polymer solution casting. It is possible to obtain a separation membrane having high peel strength and mechanical strength and excellent durability. On the other hand, by setting the basis weight to preferably 150 g/m ² or less, more preferably 120 g/m ² or less, even more preferably 90 g/m ² or less, the thickness can be reduced when used as a support, and the fluid separation element The separation membrane area per unit can be increased.

Note that the basis weight (g/m ² ) of the long fiber nonwoven fabric is calculated by the following procedure.
(1) Three pieces of long fiber nonwoven fabric of 30 cm x 50 cm are collected.
(2) Measure the mass of each sample, convert the average value of the obtained values into mass (g) per unit area, and calculate the basis weight by rounding to the first decimal place.

Moreover, it is preferable that the thickness of the long fiber nonwoven fabric is 0.030 mm or more and 0.200 mm or less. The thickness of the long-fiber nonwoven fabric is preferably 0.030 mm or more, more preferably 0.040 mm or more, and even more preferably 0.050 mm or more, so that when used as a support, excessive penetration during polymer solution casting can be prevented. etc., and good film forming properties can be obtained. In addition, it has high dimensional stability, which suppresses curling and bending after film formation, allowing for excellent processability when manufacturing fluid separation elements.The film also has high peel strength and mechanical strength, and is highly durable. A separated separation membrane can be obtained. On the other hand, by setting the thickness of the long fiber nonwoven fabric to preferably 0.200 mm or less, more preferably 0.160 mm or less, and even more preferably 0.120 mm or less, the thickness of the separation membrane can be reduced and The area of the separation membrane can be increased.

Note that the thickness (mm) of the long fiber nonwoven fabric is calculated by the following procedure.
(1) Using a pressurizer with a diameter of 10 mm, the thickness of the long-fiber nonwoven fabric is measured in 0.01 mm units at 10 points per meter at equal intervals in the width direction of the long fiber nonwoven fabric under a load of 10 kPa.
(2) Round off the average value of the above 10 points to the fourth decimal place.

The smoothness of the long fiber nonwoven fabric according to one embodiment of the present invention is preferably 10 seconds or more and 60 seconds or less on both surfaces. The smoothness of the long fiber nonwoven fabric is preferably set to 10 seconds or more, more preferably 15 seconds or more, and still more preferably 20 seconds or more, so that the coagulation liquid mainly composed of water can flow from the back side of the support to the inside during separation membrane production. By suppressing excessive permeation of the polymer solution, the polymer solution cast onto the support can be solidified after sufficiently permeating into the inside of the support, and the membrane peel strength of the formed separation membrane can be improved. Furthermore, it is possible to suppress scratches on the surface of the separation membrane caused by rubbing between the membrane forming surface and the back surface during the winding process during separation membrane production. On the other hand, by setting the smoothness of the long-fiber nonwoven fabric to preferably 60 seconds or less, more preferably 50 seconds or less, and still more preferably 45 seconds or less, air inside the support can be quickly exhausted during separation membrane production, and partial It is possible to suppress a decrease in film peel strength and to suppress the occurrence of film forming defects such as pinholes.

Note that the smoothness (seconds) of the long fiber nonwoven fabric is calculated by the following procedure.
(1) Three pieces of long fiber nonwoven fabric with a width of 10 cm in the longitudinal direction are collected.
(2) Based on JIS P8155:2010 "Paper and paperboard - Smoothness test method - Oken method" using a smoothness tester (for example, "Oken type smoothness tester EBO1-5 model" manufactured by Asahi Seiko Co., Ltd.) The smoothness was measured in Beck seconds on both sides of the long fiber nonwoven fabric at intervals of 10 cm in the width direction. For example, if the width of the nonwoven fabric is 105 cm, measurements are taken at 10 points at equal intervals of 10 cm, excluding 7.5 cm at both ends.
(3) Calculate the arithmetic mean value of the obtained measurement values for both sides, and round off to the first decimal place. The obtained values are arithmetic averaged on both sides of each of the three sampled long fiber nonwoven fabrics, rounded to the first decimal place, and determined as smoothness (seconds).

In addition, in order to keep the smoothness of this long fiber nonwoven fabric within the above range, the temperature and linear pressure on the surface of a pair of upper and lower flat temporary pressure rolls in the temporary bonding and thermocompression bonding steps of the nonwoven fabric sheet manufacturing method must be adjusted. This can be achieved by adjusting the range described below.

(Nonwoven fabric roll)
The nonwoven fabric roll of one embodiment of the present invention has a winding hardness of 35.0 g or more and 50.0 g or less.

By setting the winding hardness of the nonwoven fabric roll to 35.0 g or more, preferably 37.0 g or more, and more preferably 40.0 g or more, it is possible to obtain a nonwoven fabric roll that is free from misalignment and wrinkles when loosened. On the other hand, by setting the winding hardness of the nonwoven fabric roll to 50.0 g or less, preferably 48.0 g or less, more preferably 47.0 g or less, excessive winding tension is not applied to the nonwoven fabric roll, and a load is applied to the winding core. Since the long fiber nonwoven fabric is free from wrinkles, it is possible to obtain a nonwoven fabric roll without wrinkles.

Further, the hardness difference in the width direction of the nonwoven fabric roll is 7.0 g or more and 20.0 g or less. By setting the hardness difference in the width direction of the nonwoven fabric roll to 7.0 g or more, preferably 8.0 g or more, more preferably 9.0 g or more, it can be used as a wide support and can be used as a support when coating with a die coating method. Excellent film processability. On the other hand, by setting the hardness difference in the width direction of the nonwoven fabric roll to 20.0 g or less, preferably 19.0 g or less, more preferably 18.0 g or less, deformation due to widthwise variation when the support is lengthened It is possible to suppress the occurrence of coating defects during separation membrane production.

In addition, the winding hardness (g) and the hardness difference (g) in the width direction of the nonwoven fabric roll are calculated by the following procedure.
(1) Using a roll hardness tester (for example, "RoQ Rolling Hardness Meter" manufactured by ACA System), when the nonwoven fabric roll is left still, the nonwoven fabric roll is measured at 3 o'clock or 9 o'clock when viewed from the cross section. From the angle, measure from one end in the width direction to the other end three times in total in the same direction, and round off the arithmetic mean value of the obtained values at intervals of 0.2 cm in the width direction to the second decimal place, and then measure the nonwoven fabric roll. Calculate the winding hardness (g) of. In addition, the above-mentioned "RoQ roll hardness measuring instrument" manufactured by ACA System is equipped with a hammer on the bottom of the measuring instrument, and the hammer part hits the roll surface, the hammer hits the roll surface, decelerates, and stops. It has a mechanism that measures the negative gravitational acceleration until the hardness (unit: g, 1 g = 9.81 m/s ² ).
(2) Obtain the difference between the maximum and minimum values of the hardness data at 0.2 cm intervals in the width direction obtained by the above method, excluding 7.5 cm at both ends, round to the second decimal place, and calculate the difference in the roll width direction. Calculate the hardness difference (g).

In addition, in order to keep the winding hardness of this nonwoven fabric roll within the above range, the temperature and linear pressure on the surface of the pair of upper and lower flat temporary bonding rolls in the temporary adhesion and thermocompression bonding steps of the nonwoven fabric sheet manufacturing method will be described later. This can be achieved by adjusting the range.

In addition, in order to keep the hardness difference in the width direction of the nonwoven fabric roll within the above range, the maximum basis weight W _Max (g/m ² ) and the minimum basis weight W _Min (g/m ² ) can be achieved by adjusting it within the range described below.

The nonwoven fabric roll according to one embodiment of the present invention preferably has a winding length of 100 m or more and 20,500 m or less. By setting the winding length of the nonwoven fabric roll to preferably 100 m or more, more preferably 1000 m or more, and even more preferably 3000 m or more, it is possible to obtain a nonwoven fabric roll that has excellent handling properties during separation membrane production. On the other hand, the winding length of the nonwoven fabric roll is preferably 20,500 m or less, more preferably 15,500 m or less, and still more preferably 11,500 m or less, thereby preventing excessive winding tension from being applied to the nonwoven fabric roll and deforming the winding core. It is possible to obtain a nonwoven fabric roll that is able to suppress this and also has excellent handling properties when transporting the nonwoven fabric roll.

In the nonwoven fabric roll of one embodiment of the present invention, it is preferable that the difference in thickness between the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric is 0.010 mm or less. The difference in thickness between the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric is preferably 0.010 mm or less, more preferably 0.005 mm or less, and still more preferably 0.003 mm or less, so that the difference in thickness of the roll inner layer nonwoven fabric when the roll length is increased is It is possible to wind the film while suppressing winding misalignment.

The roll inner layer nonwoven fabric and roll outer layer nonwoven fabric described here are the inner layer nonwoven fabric within 10% of the distance on the core side of the nonwoven fabric roll minus the radius of the core, and the outermost 10% of the nonwoven fabric roll is the nonwoven fabric outer layer of the roll. and indicates the thickness of a single sheet of nonwoven fabric located within each of the above ranges.

The thickness (mm) of the long fiber nonwoven fabric and the difference in thickness (mm) are calculated by the following procedure.
(1) The roll inner layer nonwoven fabric and the roll outer layer nonwoven fabric are each sampled from three arbitrary locations.
(2) Using a pressure element with a diameter of 10 mm (for example, "Dial Gauge 2109S-10 (Measuring element: Flat measuring element 101117)" manufactured by Mitutoyo Co., Ltd.) at equal intervals of 10 cm in the width direction of the arbitrarily sampled nonwoven fabric, , the thickness is measured in units of 0.001 mm under a load of 10 kPa. For example, if the width of the nonwoven fabric is 105 cm, measurements are taken at 10 points at equal intervals of 10 cm, excluding 7.5 cm at both ends.
(3) Calculate the average value of the values measured at equal intervals above for three each of the roll inner layer nonwoven fabric and the roll outer layer nonwoven fabric, and then calculate the arithmetic mean value of the three average values each of the roll inner layer nonwoven fabric and the roll outer layer nonwoven fabric with a decimal point. The following numbers are rounded off to the fourth place to determine the thickness of the inner layer nonwoven fabric of the roll and the thickness of the nonwoven fabric outer layer of the roll.
(4) Determine the difference between the thickness of the roll inner layer nonwoven fabric and the roll outer layer nonwoven fabric.

The core used in the nonwoven fabric roll of the present invention may be made of a general paper tube or a resin such as polyethylene, polypropylene, or ABS, but the core may be reinforced with metal to prevent the core from being crushed during long winding. It is preferable to use a winding core made of a paper tube, fiber-reinforced plastic, or the like. The outer diameter size of the core of the nonwoven fabric roll is not limited, but since folding wrinkles are likely to occur at the beginning of winding, it is preferably 50 mm or more to facilitate winding, and to improve loading efficiency in terms of logistics. From this point of view, the length is preferably 200 mm or less.

The nonwoven fabric roll according to one embodiment of the present invention preferably has a roll width of 0.5 m or more and 1.5 m or less. By setting the roll width of the nonwoven fabric roll to preferably 0.5 m or more, more preferably 0.6 m or more, and still more preferably 0.7 m or more, it is possible to obtain a nonwoven fabric roll with excellent productivity during support production. On the other hand, by setting the roll width of the nonwoven fabric roll to 1.5 m or less, more preferably 1.4 m or less, and even more preferably 1.3 m or less, the width of the nonwoven fabric roll can be set to 1.3 m or less, so that the influence of the widthwise variation of the nonwoven fabric roll is not impaired during support production. A nonwoven fabric roll with excellent processability can be obtained.

Further, in the present invention, the winding deviation of the nonwoven fabric roll is preferably 0 mm or more and 8 mm or less. The winding misalignment refers to the distance between the end face of the roll and the nonwoven fabric that partially protrudes to the outside. The winding deviation of this nonwoven fabric roll is more preferably 5 mm or less. By doing so, the support can be processed without wrinkles due to meandering.

(Method for manufacturing nonwoven fabric roll)
Next, the method for manufacturing a nonwoven fabric roll of the present invention is characterized in that the following steps a to d are sequentially performed. This will be explained in detail with reference to FIG.
( Step a) After the thermoplastic resin is spun from a spinneret ( 1 ) having discharge holes to obtain long fibers, gas is passed through the cooling section ( 2 ) in a direction perpendicular to the running direction of the long fibers. After applying gas to the long fibers through the gas supply section ( 3 ) in a direction perpendicular to the traveling direction of the long fibers, the long fibers are exposed to the gas supply section ( 3 ) . A step of passing through an intake/exhaust part ( 4 ) with a length of 1 mm or more and 150 mm or less provided directly below, and suctioning and stretching at a spinning speed of 3000 m/min or more and 5500 m/min or less,
( Step b) a step of collecting the drawn long fibers on a moving net conveyor ( 6 ) to form a fiber web ( 9 ) ;
( Step c) The fiber web ( 9 ) is compressed by a pair of flat temporary pressure rolls ( 7 ) whose roll surface temperature is 60° C. or more and 120° C. or less lower than the melting point of the thermoplastic resin to a pressure of 100 N/cm or more and 700 N. A step of temporarily adhering with a linear pressure of /cm or less to obtain a nonwoven fabric sheet ( 10 ) ,
( Step d) Two or more layers of the nonwoven fabric sheets are stacked, and the surface temperature of at least one of the rolls is 20°C or more and 100°C or less higher than the roll surface temperature of the step c, by using a pair of flat rolls to achieve a pressure of 500 N/cm or more. A process of obtaining a long fiber nonwoven fabric by thermocompression bonding with a linear pressure of 5000 N/cm or less, and then winding up the long fiber nonwoven fabric to obtain a nonwoven fabric roll.

In addition, when using composite fibers such as a core-sheath type as fibers constituting the long fiber nonwoven fabric, it is preferable to do as follows. That is, the above step a is the following step a', and the melting point of the thermoplastic resin in the above step c is the melting point of the low melting point polymer.
( Step a') A high melting point polymer and a low melting point polymer having a melting point lower than the melting point of the high melting point polymer by 10° C. or more and 110° C. or less are spun from a composite spinneret ( 1 ) having a discharge hole. ,
After obtaining long fibers covered with a low melting point polymer without exposing the high melting point polymer,
applying gas to the long fibers through a cooling section ( 2 ) in a direction perpendicular to the running direction of the long fibers;
Next, after applying gas to the long fibers through the gas supply section ( 3 ) in a direction perpendicular to the running direction of the long fibers,
The long fibers are passed through an intake/exhaust part ( 4 ) with a length of 1 mm or more and 150 mm or less, which is provided directly below the gas supply part ( 3 ) ,
A step of suction stretching at a spinning speed of 3000 m/min or more and 5500 m/min or less.

( Step a) Step of suction stretching after obtaining long fibers The method for producing the long fiber nonwoven fabric constituting the nonwoven fabric roll of the present invention includes a spunbond method, a flash spinning method, a wet method, a card method, an air laid method, etc. can be mentioned.

Among these, a spunbond nonwoven fabric produced by a spunbond method is an example of a preferred embodiment. Spunbond nonwoven fabrics, which are long fiber nonwoven fabrics made of thermoplastic filaments, have excellent productivity and can suppress fuzzing, which tends to occur when short fiber nonwoven fabrics are used as supports. In addition, spunbond nonwoven fabrics are preferably used from the viewpoint that they have excellent mechanical strength and dimensional stability, and can also provide processed products with excellent durability when used as supports.

In the present invention, when the above-mentioned conjugate fibers are used as the fibers constituting the nonwoven fabric, an ordinary conjugate method can be adopted for producing the conjugate fibers.

After melting and extruding the thermoplastic resin from the spinneret ( 1 ) , gas is applied to the long fibers through the cooling section ( 2 ) in a direction perpendicular to the traveling direction of the spun long fibers ( 8 ) , and then After applying gas to the long fibers through the gas supply section ( 3 ) in a direction perpendicular to the running direction of the long fibers, the long fibers are exposed to a long fiber provided directly below the gas supply section ( 3 ) . The sample is passed through an intake/exhaust part ( 4 ) with a diameter of 1 mm or more and 150 mm or less, and is suction-stretched.

By carrying out the procedure described above, the spun long fibers are cooled, the air flow due to suction stretching is suppressed while the inflow of outside air is suppressed, and the fabric weight distribution in the width direction is not deteriorated due to yarn breakage or yarn shaking. A web can be formed.

The gas supply section ( 3 ) is additionally installed below the cooling section in order to minimize yarn sway; however, in order to minimize yarn sway, the width of the gas supply section is larger than the width of the cooling section. It is preferable that the width is longer. Note that the width of the cooling section referred to here refers to the shortest distance among the distances between the walls of the passage in which the yarn runs in the cooling section ( 2 ) , and the width of the gas supply section refers to the width of the gas supply section. In the gas supply section ( 3 ) , it refers to the shortest distance among the distances between the walls of the passage through which the yarn runs.

In addition, there is no particular specification as long as the gas is applied through the gas supply section in a direction perpendicular to the running direction of the long fibers, but a mesh may be used to rectify the flow within the gas supply section to suppress yarn sway. It is preferable that it is included. The size of this mesh is preferably 20 mesh or more, more preferably 40 mesh or more, and even more preferably 100 mesh or more.

Regarding the suction/exhaust part ( 4 ) , in order to take in the inflow of gas necessary for suction, it is preferable to arrange a mesh structure or a plate with regularly arranged holes such as a staggered pattern.

The length of the intake/exhaust part is preferably 1 mm or more and 150 mm or less. If the length of the suction/exhaust part is 1 mm or more, more preferably 5 mm or more, and still more preferably 10 mm or more, the inflow of gas necessary for suction is suppressed from increasing the wind speed at the suction/exhaust part, and long fibers are prevented from breaking. can be reduced. Further, if the length of the intake and exhaust part is 150 mm or less, more preferably 100 mm or less, and even more preferably 75 mm or less, it is possible to suppress the yarn sway of the long fibers due to the inflow of outside air, and the fibers have excellent fabric weight distribution in the width direction. You can get the web. Note that the "length of the intake/exhaust section" refers to the vertical distance (distance in the vertical direction in Fig. 1) of the portion of the intake/exhaust section ( 4 ) that faces the passage through which the thread runs. .

Regarding suction stretching, it is common to use an ejector ( 5 ) to stretch with air. At this time, the fibers may shrink during temporary bonding or thermocompression bonding in the subsequent process, causing wrinkles, or heat rolls. In order to prevent the low melting point polymer component from fusing and reducing productivity, it is preferable to crystallize the long fibers constituting the obtained fiber web to a higher degree of orientation, and the spinning speed is 3000 m/min. The speed is preferably at least 3,500 m/min, more preferably at least 4,000 m/min. Furthermore, by suppressing excessive oriented crystallization of fibers, it is possible to obtain thermal adhesion that contributes to improving the mechanical strength of the spunbond nonwoven fabric, so the spinning speed is preferably 5500 m/min or less, and more preferably Preferably it is 5000 m/min or less, more preferably 4500 m/min or less.

( Step b) Step of forming a fibrous web The long fibers obtained in step a above are collected on a moving net conveyor ( 6 ) to obtain a fibrous web ( 9 ) . Collecting refers to sequentially depositing the long fibers ejected from the ejector ( 5 ) onto the rotating net conveyor ( 6 ) , and the net conveyor is the belt section of the belt conveyor. refers to net-like objects such as punching plates, net-like materials, or porous materials. However, the collected long fibers may fall into the net conveyor from the penetrating portion of the net, the punching plate, or the pores of the porous body (hereinafter referred to as ``holes, etc.''), or It is preferable to appropriately set the size of the pores, etc., taking into consideration the resin constituting the long fibers, the fiber diameter of the long fibers, etc., so that the holes do not become clogged. Note that the net-like portion may be made of metal or synthetic resin.

( Step c) Step of obtaining a nonwoven fabric sheet The fibrous web ( 9 ) collected and formed on the net conveyor ( 6 ) is brought into contact with a pair of flat temporary pressure rolls ( 7 ) to suppress fuzzing. Although there is no restriction in any way, it is preferable to use a heat treatment process in which a flat temporary pressure-bonding roll ( 7 ) heated to a predetermined temperature is brought into contact with the fiber web ( 9 ) . The roll has no unevenness.

Regarding the heat treatment process in this temporary adhesion, the surface temperature of the flat temporary pressure roll is 60°C or more and 120°C or less lower than the melting point of the polymer with the lowest melting point that constitutes the fibrous web present on the surface of the fibrous web. It is preferable. That is, when this melting point is (T _m ), the surface temperature of the flat temporary pressure roll is preferably (T _m -60) °C or more and (T _m -120) °C or less, and (T _m -70) )°C or more and (T _m -110)°C or less is more preferable, and (T _m -80)°C or more and (T _m -100)°C or less is most preferable. If the surface temperature of the flat temporary pressure roll is lower than (T _m −120)° C., the thermocompression bonding of the fibrous web will be insufficient, resulting in poor conveyance of the fibrous web. In addition, if the surface temperature of the flat temporary pressure roll is higher than (T _m -60)°C, the heat treatment will be too strong and the constituent fibers in the surface layer will become fused, making it impossible to obtain sufficient mechanical strength. First, the adhesion during thermocompression bonding in post-processing is poor.

The linear pressure when temporarily bonding the fiber web ( 9 ) with a pair of flat temporary pressure rolls ( 7 ) is preferably in the range of 100 N/cm or more and 700 N/cm or less, more preferably 200 N/cm or more and 600 N/cm or less. is within the range of When the linear pressure is 200 N/cm or more, a linear pressure sufficient for forming a fibrous web can be obtained. When the linear pressure is 600 N/cm or less, sufficient mechanical strength can be obtained without the adhesion between the fibers becoming too strong.

( Step d) Step of obtaining a nonwoven fabric roll by obtaining a long fiber nonwoven fabric The nonwoven fabric sheet ( 10 ) obtained by temporary adhesion may be further thermocompressed with a pair of upper and lower flat rolls, but in the width direction. In order to improve the uniformity of the basis weight, it is preferable to divide the sheet into 2 to 5 parts in the width direction and overlap them.

When superimposing the nonwoven fabric sheets, it is preferable to superimpose the nonwoven fabric sheets so as to satisfy the following formula 1 and perform thermocompression bonding. 0.90≦W _Min /W _Max ≦1.00 (1 )
Here, in the width direction of the stacked nonwoven fabric sheets, the maximum basis weight W _Max (g/m ² ) and the minimum basis weight W _Min (g/m ² ) are assumed. Thereby, the lowest fabric weight parts at the ends are laminated in the same direction, the uniformity of the fabric weight in the width direction is deteriorated, and a nonwoven fabric with excellent processability when used as a support can be obtained.

Furthermore, in order to improve the uniformity of the basis weight, a melt-blown nonwoven fabric may be placed between the layers of the nonwoven fabric sheets and overlapped.

In addition, in this invention, W _Min and W _Max of the said nonwoven fabric sheet shall employ the value calculated by the following procedure.
(1) Calculate the average value of the fabric weight distribution at 5 mm intervals, which is measured by scanning 40 times or more with an X-ray fabric weight meter (for example, "Accure X3" manufactured by Hutech Co., Ltd.).
(2) Calculate by averaging the basis weight data corresponding to 0 to 20 cm at both ends from the fiber web width dividing position, rounding to the second decimal place, and calculating the minimum value W _Min and maximum value W _Max . Note that if one side of W _Min is W _Max , the next highest value is adopted.

As for thermocompression bonding, it is more preferable to thermocompress and integrate using a pair of upper and lower flat rolls. For flat rolls used in thermocompression bonding, metal rolls or elastic rolls can be used. Examples of the elastic roll include so-called paper rolls such as paper, cotton, and aramid paper, and rolls made of resins such as urethane resin, epoxy resin, silicone resin, and hard rubber. As a pair of flat rolls, a metal roll and a metal roll may be used as a pair, or a metal roll and an elastic roll may be used as a pair.

In addition, by suppressing the fusion of the fibers on the surface of the long-fiber nonwoven fabric and maintaining its shape, it is possible to obtain an anchoring effect that suppresses the peeling of the separation membrane when used as a support. It is preferable to provide a temperature difference between them. In particular, a method in which the nonwoven fabric sheet is thermocompressed by a heated metal roll and an unheated elastic roll can be preferably adopted from the viewpoint of the above-mentioned anchoring effect.

The thermocompression bonding method for obtaining the long fiber nonwoven fabric constituting the nonwoven fabric roll includes a pair of flat rolls in which the surface temperature of at least one of the rolls is 20°C or more and 100°C or less higher than the roll surface temperature at the time of temporary bonding. , it is preferable to carry out thermocompression bonding. That is, the surface temperature on the high temperature side of the flat roll is preferably 20°C or more and 100°C or less, more preferably 30°C or more and 90°C or less, and most preferably 40°C or more and 80°C or less. By setting the roll surface temperature to 100°C or less, the density becomes too high and by suppressing partial film formation, when used as a support, it is possible to suppress membrane peeling due to insufficient penetration of the support membrane. can. Moreover, by setting the roll surface temperature to 20° C. or higher, the nonwoven fabric sheet can be sufficiently thermocompressed, the surface can be sufficiently smoothed, and the support film can be applied uniformly when used as a support.

Further, the temperature of the other (lower temperature side) flat roll of the pair of flat rolls is preferably 40° C. or more and 120° C. or less than the temperature of the high temperature side flat roll. By setting the temperature difference between the flat roll on the low-temperature side and the flat roll on the high-temperature side to 40°C or more, more preferably 60°C or more, it is possible to suppress the formation of extremely high-density areas on the surface of the long fiber nonwoven fabric, and to improve the support. There is little peeling of the film due to insufficient penetration of the support film solution during body coating, and good film formability can be obtained. On the other hand, by setting the temperature difference between the flat roll on the low-temperature side and the flat roll on the high-temperature side to 120°C or less, more preferably 100°C or less, sufficient thermocompression bonding can be achieved, and there is less over-penetration etc. during support coating. It is possible to obtain excellent workability.

Furthermore, the temperature during thermocompression bonding of the upper and lower rolls is preferably within a range of ±15°C or less, more preferably within a range of ±10°C, centered around the temperature at the start of processing, and is more preferably within a range of ±5°C. The following ranges are more preferable. Generally speaking, it is difficult to strictly control the temperature of an unheated elastic roll, but it is possible to carry out a preliminary operation with it in contact with a heated metal roll before processing, or to control the temperature of the elastic roll during processing. If it becomes too high, try air blowing, shower ring, contact with a cooling roll, etc. If it becomes too low, try heating it with an infrared heater, circulating a heat medium inside the roll, or contacting it with a heating roll, etc. It can be controlled by

The linear pressure of thermocompression bonding for obtaining the long fiber nonwoven fabric constituting the nonwoven fabric roll is preferably in the range of 500 N/cm or more and 5000 N/cm or less. Preferably, it is in the range of 500 N/cm or more and 5000 N/cm or less, more preferably 750 N/cm or more and 4000 N/cm or less, and still more preferably 1000 N/cm or more and 3000 N/cm or less. When the linear pressure is 500 N/cm or more, the fiber web is sufficiently thermocompressed and the surface is smoothed, resulting in excellent film forming processability when used as a support. In addition, by setting the linear pressure to 5000 N/cm or less, it is possible to suppress the formation of extremely high-density areas on the surface of the long fiber nonwoven fabric. There is little film peeling, etc., and good film formability can be obtained.

Winding machines for winding long fiber nonwoven fabrics bonded by thermocompression include the center winding system, in which the material web is wound around the surface of the winding roll by rotating the central axis of the core, and A surface winding method may be used in which the roll core is placed on two or more support rollers and the material web is wound around the roll core by rotating at least one of the support rollers. Further, it is preferable that the holding pressure and the winding tension can be adjusted and winding can be performed more stably.

Regarding a nonwoven fabric roll wound up with a thermocompression-bonded long fiber nonwoven fabric, it is preferable to slit both ends when winding it up as a nonwoven fabric roll, since a shrinkage difference occurs between the sheet ends and the center area. The width of the ear slit is preferably 1 cm or more and 10 cm or less. Preferably, the range is 1 cm or more and 10 cm or less, more preferably 2 cm or more and 9 cm or less, and even more preferably 3 cm or more and 8 cm or less. If the ear slit width is 1 cm or more, it is possible to wind up the film without causing slit defects due to breakage when the ear slit portion meanders. Furthermore, if the length is 10 cm or less, loss of the nonwoven fabric roll can be reduced and productivity is also excellent.

Further, the winding tension when winding up the thermocompression-bonded long fiber nonwoven fabric is preferably 40 N/m or more and 170 N/m or less. Preferably, the range is 40 N/m or more and 160 N/m or less, more preferably 50 N/m or more and 150 N/m or less, and even more preferably 60 N/m or more and 150 N/m or less. When the winding tension is 40 N/m or more, it is possible to wind up the long fiber nonwoven fabric without loosening and causing wrinkles in the nonwoven fabric roll. Moreover, by setting the winding tension to 170 N/m or less, it is possible to wind the nonwoven fabric roll without the tension becoming too strong and causing wrinkles in the nonwoven fabric roll.

Next, the nonwoven fabric roll of the present invention and its manufacturing method will be specifically described based on Examples. However, the present invention is not limited only to these examples.

[Measuring method]
The evaluation method used in Examples and its measurement conditions will be explained. In the measurement of each physical property, unless otherwise specified, the measurement was performed based on the method described above.

(1) Intrinsic viscosity (IV):
The intrinsic viscosity (IV) of polyethylene terephthalate resin was measured by the following method. 8 g of a sample was dissolved in 100 ml of orthochlorophenol, and the relative viscosity ηr was determined by the following formula using an Ostwald viscometer at a temperature of 25°C.
・η _r =η/η ₀ = (t×d)/(t ₀ ×d ₀ )
(Here, η is the viscosity of the polymer solution, η ₀ is the viscosity of orthochlorophenol, t is the falling time of the solution (seconds), d is the density of the solution (g/cm ³ ), and t0: is the falling of orthochlorophenol. Time (seconds) and d ₀ represent the density of orthochlorophenol (g/cm ³ ), respectively.)
Next, the intrinsic viscosity (IV) was calculated from the above relative viscosity η _r using the following formula.
- Intrinsic viscosity (IV) = 0.0242η _r +0.2634.

(2) Melting point (℃):
The melting point of the thermoplastic resin used was measured using a differential scanning calorimeter (TA Instruments Q100) under the above conditions, and the average value of the endothermic peak apex temperature was calculated and used as the melting point of the measurement target.

(3) Maximum basis weight W _Max (g/m ² ), minimum basis weight W _Min (g/m ² ) in the width direction of the nonwoven fabric sheet:
The maximum basis weight W _Max and the minimum basis weight W _Min in the width direction of the nonwoven fabric sheet were measured by the method described above using "Accure X3" manufactured by Hutech Co., Ltd. as an X-ray basis weight meter.

(4) Smoothness of long fiber nonwoven fabric (seconds):
The smoothness of the long fiber nonwoven fabric was measured by the method described above using "Oken type smoothness tester model EBO1-5" manufactured by Asahi Seiko Co., Ltd. In addition, in Table 1, smoothness (1) refers to the smoothness of the surface with high temperature during thermocompression bonding, and smoothness (2) refers to the smoothness of the surface with low temperature during thermocompression bonding. Generally, the value is smoothness (1)>smoothness (2).

(5) Rolling hardness (g) of nonwoven fabric roll, hardness difference in width direction (g):
The winding hardness and the hardness difference in the width direction of the nonwoven fabric roll were measured by the method described above using "RoQ roll winding hardness meter" manufactured by ACA System as a roll hardness meter.

[Example 1]
(fibrous web)
As a fiber whose main component is a thermoplastic resin, a composite fiber consisting of the following high melting point polymer as a core component and the following low melting point polymer as a sheath component was used. The thermoplastic resin used is shown below.
High melting point polymer: A polyethylene terephthalate resin having an intrinsic viscosity (IV) of 0.65, a melting point of 260°C, and containing 0.3% by mass of titanium oxide, dried to a moisture content of 10 ppm or less.
Low melting point polymer: has an intrinsic viscosity (IV) of 0.66, an isophthalic acid copolymerization rate of 11 mol%, a melting point of 230°C, and a copolymerized polyethylene terephthalate resin containing 0.2% by mass of titanium oxide and a moisture content of 10 ppm. Below is the dried one.

The above core component was melted at 295°C and the sheath component at 280°C, and the core/sheath composite ratio was 80/20 by mass to form a concentric core-sheath type with a circular cross section. A spun long fiber was obtained. The spun long fibers ( 8 ) are exposed to gas through the cooling section ( 2 ) in a direction perpendicular to the running direction, and then the length is Gas was applied to the long fibers through a 100 mm gas supply ( 3 ) . Note that the gas supply section ( 3 ) was 50 mm larger than the width of the cooling section, and had a 100 mesh wire mesh mounted inside. After applying gas through the gas supply section, it passes through a suction and exhaust section ( 4 ) with a length of 20 mm provided directly below the gas supply section, and is suctioned with compressed air at a spinning speed of 4300 m/min using an ejector ( 5 ) . A fibrous web ( 9 ) was obtained by stretching and collecting on a moving net conveyor ( 6 ) . The fibrous web collected as described above was passed through a pair of upper and lower metal flat temporary pressure rolls ( 7 ) , and the surface temperature of each roll of the temporary pressure rolls was 135°C and the linear pressure was 490N/cm. A nonwoven fabric sheet ( 10 ) with a width of 2.3 m and an average single fiber diameter of 11.4 μm and a basis weight of 34.5 g/m ² was obtained by temporarily bonding.

(Nonwoven fabric roll)
The above nonwoven fabric sheet was divided into two parts of 1.15 m, and the two layers were overlapped and thermocompression bonded. For stacking, check the basis weight corresponding to 0 to 20 cm at both ends from the position when the nonwoven fabric sheet is divided into two, and the W _min at one end is 34.2 g/m ² and the W _MAX at the end of the two divided parts is 35. It was carried out so that 8 g/m ² overlapped.

The stacked sheets were passed through a set of three flat rolls and bonded under heat. The upper flat roll is an elastic roll made of resin with a hardness (ShoreD) of 91 and an average surface roughness Ra of 4 μm, with a surface temperature of 130°C, the middle flat roll is a metal roll with a surface temperature of 195°C, and the lower flat roll is a metal roll with a surface temperature of 195°C. An elastic roll made of resin with a hardness (ShoreD) of 75 and an average surface roughness Ra of 4 μm, the surface temperature of which is 130°C, is thermocompressed by passing it between the middle and bottom of the flat roll, and then linear pressure is applied between the top and middle of the flat roll. Thermocompression bonding was carried out at 1850 N/cm.

Thereafter, the surface of the heat-pressed sheet that was in contact with the metal roll of the medium flat roll was brought into contact with a metal cooling roll whose surface temperature was 45°C for 1 second, and then, while slitting 2.5 cm of both ends, At a sheet winding tension of 120 N/m, the sheet was wound for 5000 m around a fiber-reinforced plastic core with an inner diameter of 17.5 cm and a wall thickness of 10 mm using a twin-axis surface winder to obtain a nonwoven fabric roll with a width of 1.1 m.

The obtained nonwoven fabric had a basis weight of 70 g/m ² , an apparent density of 0.82 g/cm ³ , and a smoothness of 45 seconds and 14 seconds for the metal roll bonding surface and the elastic roll bonding surface during thermocompression bonding, respectively.

The rolled nonwoven fabric roll has no wrinkles, winding deviation is 0 mm, the winding hardness is 40.5 g, the hardness difference is 8.2 g, and the thickness of the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric are 0.086 mm and 0. It was .086 mm.

[Example 2]
The same method as in Example 1 was carried out except that the winding length of the nonwoven fabric roll was changed to 12,000 m.

The rolled nonwoven fabric roll has no wrinkles, winding deviation is 0 mm, winding hardness is 42.3 g, hardness difference is 8.4 g, and the thickness of the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric are 0.086 mm and 0. It was .086 mm.

[Example 3]
Example 2 was carried out in the same manner as in Example 2, except that the length of the gas supply section was 20 mm and the suction/exhaust section was 100 mm when obtaining a fibrous web. The W _min of the nonwoven fabric sheet is 33.4 g/m ² and the W _MAX is 36.6 g/m ² . The obtained nonwoven fabric has a basis weight of 70 g/m ² , an apparent density of 0.81 g/cm ³ , and a smoothness of The adhesion times for the metal roll and elastic roll surfaces during thermocompression bonding were 43 seconds and 12 seconds, respectively.

The wound nonwoven fabric roll has no wrinkles, winding deviation is 0 mm, winding hardness is 43.1 g, hardness difference is 19.6 g, and the thickness of the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric are 0.085 mm and 0. It was .087 mm.

[Example 4]
Example 2 was carried out in the same manner as in Example 2, except that the length of the intake and exhaust part was 5 mm when obtaining the fibrous web. The W _min of the nonwoven fabric sheet is 34.4 g/m ² and the W _MAX is 35.6 g/m ² . The obtained nonwoven fabric has a basis weight of 70 g/m ² , an apparent density of 0.82 g/cm ³ , and a smoothness of The adhesion times for the metal roll and elastic roll surfaces during thermocompression bonding were 44 seconds and 13 seconds, respectively.

The rolled nonwoven fabric roll has no wrinkles, winding deviation is 0 mm, the winding hardness is 42.1 g, the hardness difference is 17.2 g, and the thickness of the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric are 0.085 mm and 0. It was .086 mm.

[Example 5]
Example 2 was carried out in the same manner as in Example 2, except that the fibrous web was divided into three parts in the width direction, overlapped and thermocompression bonded, and both ends were slit by 3.0 cm to form a nonwoven fabric roll having a width of 0.7 m. The obtained nonwoven fabric had a basis weight of 70 g/m ² , an apparent density of 0.78 g/cm ³ , and a smoothness of 42 seconds and 12 seconds for the metal roll bonding surface and the elastic roll bonding surface during thermocompression bonding, respectively.

The rolled nonwoven fabric roll has no wrinkles, winding deviation is 0 mm, the winding hardness is 41.7 g, the hardness difference is 7.5 g, and the thickness of the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric are 0.088 mm and 0. It was .089 mm.

[Example 6]
Example 2 was carried out in the same manner as in Example 2, except that the fibrous web was divided into four parts in the width direction, overlapped and thermocompression bonded, and both ends were slit by 3.2 cm to form a nonwoven fabric roll with a width of 0.5 m. The obtained nonwoven fabric had a basis weight of 70 g/m ² , an apparent density of 0.77 g/cm ³ , and a smoothness of 41 seconds and 11 seconds for the metal roll bonding surface and the elastic roll bonding surface during thermocompression bonding, respectively.

The rolled nonwoven fabric roll has no wrinkles, winding deviation is 0 mm, the winding hardness is 41.5 g, the hardness difference is 7.1 g, and the thickness of the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric are 0.089 mm and 0. It was .089 mm.

[Comparative example 1]
Example 2 was carried out in the same manner as in Example 2, except that when obtaining a fibrous web, the gas supply section was set to 0 mm, and the suction/exhaust section was set to 150 mm. When obtaining a fibrous web, it was confirmed that the long fibers swayed significantly at both ends. The obtained nonwoven fabric had a basis weight of 70 g/m ² , an apparent density of 0.81 g/cm ³ , and a smoothness of 45 seconds and 14 seconds for the metal roll bonding surface and the elastic roll bonding surface during thermocompression bonding, respectively.

Although the rolled nonwoven fabric roll had no wrinkles and the winding misalignment was 0 mm, unevenness was observed on the surface of the nonwoven fabric roll, the winding hardness was 41.6 g, the hardness difference was 24.6 g, and the thickness of the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric were found. The thicknesses were 0.086 mm and 0.086 mm, respectively.

[Comparative example 2]
Example 2 was carried out in the same manner as in Example 2, except that the length of the intake and exhaust part was 150 mm when obtaining a fibrous web. When obtaining a fibrous web, it was confirmed that the yarn sway of the long fibers increased over the entire width. The obtained nonwoven fabric had a basis weight of 70 g/m ² , an apparent density of 0.82 g/cm ³ , and a smoothness of 44 seconds and 14 seconds for the metal roll bonding surface and the elastic roll bonding surface during thermocompression bonding, respectively.

Although the rolled nonwoven fabric roll had no wrinkles and the winding misalignment was 0 mm, unevenness was observed on the surface of the nonwoven fabric roll, the winding hardness was 41.8 g, the difference in hardness was 23.2 g, and the thickness of the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric were found. The thicknesses were 0.086 mm and 0.087 mm, respectively.

[Comparative example 3]
Example 2 was carried out in the same manner as in Example 2, except that the intake and exhaust portions were set to 0 mm when obtaining a fibrous web. When obtaining a fibrous web, the yarns of the long fibers swayed across the entire width and frequently broke, and during temporary bonding, the fibrous web wound around the flat temporary pressure roll, making it impossible to collect it.

[Comparative example 4]
In Example 2, when obtaining a fibrous web, the moving speed of the net conveyor was adjusted so that the fabric weight was 69 g/m ² . The obtained nonwoven fabric was divided into two 1.15 m nonwoven fabric sheets, and thermocompression bonding was carried out in the same manner as in Example 2 using only one side. The obtained nonwoven fabric had a basis weight of 70 g/m ² , an apparent density of 0.82 g/cm ³ , and a smoothness of 45 seconds and 14 seconds for the metal roll bonding surface and the elastic roll bonding surface during thermocompression bonding, respectively.

Although the rolled nonwoven fabric roll had a winding misalignment of 0 mm, some wrinkles occurred during winding, the winding hardness was 43.2 g, the difference in hardness was 25.3 g, and the thickness of the roll outer layer nonwoven fabric and the roll inner layer nonwoven fabric were 0.087 mm and 0.088 mm, respectively.

<Summary>
Separation membranes were formed from the nonwoven fabric rolls of Examples 1 to 6 and Comparative Examples 1, 2, and 4 by the following die coating method.

(separation membrane formation)
The obtained nonwoven fabric roll was unwound at a speed of 12 m/min, the surface with high smoothness was used as the coated side using a die coating method, and polysulfone ("Udel" (registered trademark) manufactured by Solvay Advanced Polymers, Inc. - P3500) was applied thereon. ) was applied to a thickness of 35 μm using a die coating method at room temperature (20°C), immediately immersed in pure water at room temperature (20°C) for 10 seconds, and then heated to 75°C. The membrane was immersed in pure water at a temperature of 90° C. for 120 seconds, and then wound up with a tension of 120 N/m to form a polysulfone membrane, thereby producing a separation membrane.

As a result, when the nonwoven fabric rolls of Examples 1 to 6 were used, there were no wrinkles or coating defects during the coating process, and the processability was good. On the other hand, in Comparative Examples 1 and 2, wrinkles occurred after the separation membrane was applied, and in Comparative Example 4, wrinkles occurred from the time of unwinding, and coating defects also occurred during processing, resulting in poor workability.

From these results, as shown in Table 1, a nonwoven fabric roll is obtained by winding up a long fiber nonwoven fabric made of fibers containing thermoplastic resin as a main component, and the apparent density of the long fiber nonwoven fabric is 0.70 g/cm ³ or more and 0.90 g/cm ³ or less, the winding hardness of the nonwoven fabric roll is 35.0 g or more and 50.0 g or less, and the hardness difference in the roll width direction is 7.0 g or more and 20.0 g By using the following nonwoven fabric roll, it has sufficient mechanical strength and dimensional stability when used as a separation membrane support, and has excellent support membrane coating processability with a wide die coating method. A nonwoven fabric roll was obtained.

The nonwoven fabric roll of the present invention is a nonwoven fabric roll that has sufficient mechanical strength and dimensional stability, and has excellent film coating processability using a wide die coating method, so it is particularly suitable for applications such as water treatment. It can be suitably used in a wide range of fields including separation membrane supports.

1: Spinneret 2: Cooling section 3: Gas supply section 4: Intake/exhaust section 5: Ejector 6: Net conveyor 7: Temporary pressure roll 8: Spun long fibers 9: Fiber web 10: Nonwoven fabric sheet 11: Long fibers arrow indicating the direction of travel

Claims (10)

A nonwoven fabric roll formed by winding up a long fiber nonwoven fabric made of fibers containing a thermoplastic resin as a main component, wherein the apparent density of the long fiber nonwoven fabric is 0.70 g/cm ³ or more and 0.90 g/cm ³ or less, the winding hardness of the nonwoven fabric roll is 35.0 g or more and 50.0 g or less, and the hardness difference in the roll width direction is 7.0 g or more and 20.0 g or less. The nonwoven fabric roll has a winding length of 100 m or more and 20,500 m or less, and a difference between the thickness of the long fiber nonwoven fabric in the outer layer of the roll and the thickness of the long fiber nonwoven fabric in the inner layer of the roll is 0.010 mm or less. Non-woven roll. The nonwoven fabric roll according to claim 1 or 2, wherein the nonwoven fabric roll has a roll width of 0.5 m or more and 1.5 m or less. The nonwoven fabric roll according to claim 1 or 2, wherein the long fiber nonwoven fabric has a smoothness of 10 seconds or more and 60 seconds or less on both surfaces. The nonwoven fabric roll according to claim 1 or 2, wherein the thermoplastic resin is a polyester resin. A method for manufacturing a nonwoven fabric roll, which sequentially performs the following steps a to d.
( Step a) After obtaining long fibers by spinning the thermoplastic resin from a spinneret ( 1 ) having discharge holes,
applying gas to the long fibers through a cooling section ( 2 ) in a direction perpendicular to the running direction of the long fibers;
Next, after applying gas to the long fibers through the gas supply section ( 3 ) in a direction perpendicular to the running direction of the long fibers,
The long fibers are passed through an intake/exhaust section ( 4 ) with a length of 1 mm or more and 150 mm or less, which is provided directly below the gas supply section ( 3 ) , and are suction-drawn at a spinning speed of 3000 m/min or more and 5500 m/min or less. Step ( step b) of collecting the stretched long fibers on a moving net conveyor ( 6 ) to form a fiber web ( 9 ) ( step c) The step of collecting the drawn long fibers on a moving net conveyor (6) to form a fiber web ( 9 ) . The nonwoven fabric sheet ( 10 ) ( Step d) Layering two or more layers of the nonwoven fabric sheets, using a pair of flat rolls in which at least one roll surface temperature is higher than the roll surface temperature in Step c by 20° C. or more and 100° C. or less, A process of obtaining a long fiber nonwoven fabric by thermocompression bonding with a linear pressure of 500 N/cm or more and 5000 N/cm or less, and then winding up the long fiber nonwoven fabric to obtain a nonwoven fabric roll. The method for manufacturing a nonwoven fabric roll according to claim 6, wherein the step a is the following step a', and the melting point of the thermoplastic resin in the step c is the melting point of a low melting point polymer.
( Step a') A high melting point polymer and a low melting point polymer having a melting point lower than the melting point of the high melting point polymer by 10° C. or more and 110° C. or less are spun from a composite spinneret ( 1 ) having a discharge hole. ,
After obtaining long fibers covered with a low melting point polymer without exposing the high melting point polymer,
applying gas to the long fibers through a cooling section ( 2 ) in a direction perpendicular to the running direction of the long fibers;
Next, after applying gas to the long fibers through the gas supply section ( 3 ) in a direction perpendicular to the running direction of the long fibers,
The long fibers are passed through an intake/exhaust part ( 4 ) with a length of 1 mm or more and 150 mm or less, which is provided directly below the gas supply part ( 3 ) ,
A process of suction stretching at a spinning speed of 3000 m/min or more and 5500 m/min or less The nonwoven fabric roll according to claim 6 or 7, wherein the thermoplastic resin in step a is a polyester resin, or the high melting point polymer and/ or low melting point polymer in step a' is a polyester resin. Production method. In step d, the nonwoven fabric sheet obtained in step c is divided in the width direction, and the nonwoven fabric sheets are stacked so as to satisfy the following formula 1, and are bonded under heat and pressure to obtain a long fiber nonwoven fabric. The method for manufacturing a nonwoven fabric roll according to claim 6 or 7, wherein the long fiber nonwoven fabric is then wound up to obtain a nonwoven fabric roll.
0.90≦W _Min /W _Max ≦1.00 (1)
Here, in the width direction of the stacked nonwoven fabric sheets, the maximum basis weight W _Max (g/m ² ) and the minimum basis weight W _Min (g/m ² ) are assumed. The apparent density of the long fiber nonwoven fabric is 0.70 g/cm ³ or more and 0.90 g/cm ³ or less, the winding hardness of the nonwoven fabric roll is 35.0 g or more and 50.0 g or less, and the hardness difference in the roll width direction The method for producing a nonwoven fabric roll according to claim 6 or 7, wherein the amount is 7.0 g or more and 20.0 g or less.

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