JP2006265765A - Sea-island type fiber, method for producing polyester island fiber, and fiber sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sea-island type fiber enabling a waste fluid thereof to be easily treated, scarcely causing a load to the environment, and capable of forming a fine polyester having a uniform fiber diameter. <P>SOLUTION: This sea-island type fiber is formed by using polybutylene succinate as a sea component and a polyester as an island component, wherein the polyester has a mass decreasing rate of ≤5 mass%, when measured under a condition of decomposing and removing the polybutylene succinate by a hydrolase. It is preferable that lipase is used as the hydrolase and a resin component selected from polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate is used as the island component. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sea island type fiber, a method for producing a polyester island fiber from the sea island type fiber, and a fiber sheet containing the polyester island fiber formed from the sea island type fiber.

  Polyester fibers are widely used because they are close to natural fibers, resistant to heat, and cheap. As such a polyester fiber, one having a fineness exceeding 0.55 dtex is generally used, and in some cases, a thin polyester fiber having a diameter of about 0.11 dtex (diameter of about 3.2 μm) is also commercially available. Yes. If the polyester fiber has a small fineness and is thin, it can be expected to be used for an unprecedented application. Therefore, a thinner polyester fiber has been awaited. For example, if a thinner polyester fiber is used as a separator constituting fiber for an electric double layer capacitor, the internal resistance can be lowered by reducing the thickness of the separator in addition to improving the electrical insulation performance and electrolyte retention of the separator. Various performances can be improved.

  As a method for obtaining not only polyester fibers but also fine fibers, the applicant of the present application stated that “it consists of a biodegradable polymer component and a polymer component that is difficult to remove as a remover for the biodegradable polymer component. This is a composite fiber characterized in that "(Patent Document 1). In this patent document 1, as a biodegradable polymer component, “starch-based polymer component such as starch or a copolymer of starch and ethylene, chitosan-based polymer component such as cellulose-based polymer component, aliphatic polyester” And chemical production systems such as ε-caprolactone, lactic acid system, glycol system, and modified polyvinyl alcohol system ”, and“ resolvents, enzymes, microorganisms ” In addition, as an easily removable component when an alkaline solution is used as a remover, “polyolefins such as polyethylene, polypropylene, and polystyrene, nylons 11, nylon 12, nylon 6, nylon 66, and nylons such as modified nylon” Polyester, polyester, modified polyester, etc., ester elastomer Mer, exemplified olefinic elastomers, urethane-based elastomer "a.

  On the other hand, there is known a method for obtaining fine fibers comprising a polyester island component by removing the sea component of a sea-island fiber having an island component of a polyester component and a sea component of polystyrene with an organic solvent such as trichlorethylene.

JP-A-8-188922 (Claim 1, paragraph numbers 0012 to 0014, etc.)

  When a thin polyester fiber is obtained by the method disclosed in Patent Document 1, that is, a sea-island type fiber having a biodegradable polymer component as a sea component and a polyester component as an island component is spun. When the biodegradable polymer component, which is the sea component of the sea-island fiber, is removed with an alkaline solution, the polyester island component is also hydrolyzed, as is known as weight loss processing of the polyester fiber. There arises a problem that variations occur in the fiber diameter of the thin fibers.

  On the other hand, when the sea component is removed with an organic solvent, since the polyester island component is not removed, fine fibers made of the polyester island component having a uniform fiber diameter can be obtained. In addition, it was a method with a heavy environmental load.

  The present invention has been made to solve the problems that occur when thin polyester fibers such as those described above are obtained from sea-island fibers. The waste liquid is easy to treat, has a low environmental impact, and has a fiber diameter. It is an object of the present invention to provide a sea island type fiber capable of forming uniform thin polyester fibers, a method for producing a polyester island fiber from the sea island type fiber, and a fiber sheet containing the polyester island fiber formed from the sea island type fiber. .

  The invention according to claim 1 of the present invention is as follows: “Polybutylene succinate is used as a sea component, and polyester having a mass reduction rate of 5 mass% or less under the condition that the polybutylene succinate is decomposed and removed by a hydrolase is used as an island component. It is a sea-island type fiber characterized by

  The invention according to claim 2 of the present invention is “the sea-island fiber according to claim 1, wherein the hydrolase is lipase”.

  The invention according to claim 3 of the present invention is characterized in that “the island component comprises a resin component selected from polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate”. Sea-island fiber ".

  The invention according to claim 4 of the present invention is the polyester island fiber characterized in that the sea-island fiber according to any one of claims 1 to 3 is decomposed and removed by a hydrolase. Manufacturing method ".

  The invention according to claim 5 of the present invention is “a fiber sheet comprising polyester island fibers formed from the sea-island fiber according to any one of claims 1 to 3”. .

  According to the invention of claim 1 of the present invention, a polybutylene succinate that is a sea component is formed by using a polyester having a mass reduction rate of 5 mass% or less under conditions where polybutylene succinate is decomposed and removed by a hydrolase as an island component. This is a sea-island type fiber that can form polyester island fibers having a uniform fiber diameter because the island component is hardly reduced even when hydrolyzed by hydrolyzing enzyme. In addition, polybutylene succinate can be decomposed and removed by a hydrolase, and can be processed without destroying the environment even if the decomposed monomer or the like is left or discarded. It is also possible to re-polymerize and use the decomposed monomer or the like.

  According to the invention of claim 2 of the present invention, since the hydrolase is lipase, polybutylene succinate, which is a sea component, can be easily decomposed and removed.

  According to the invention of claim 3 of the present invention, since polyethylene terephthalate, polybutylene terephthalate, or polytrimethylene terephthalate is excellent in versatility, polyester island fibers applicable to various uses can be formed.

  According to the invention of claim 4 of the present invention, since the sea component is removed by the hydrolase, polyester island fibers having a uniform fiber diameter can be produced. Moreover, even if the decomposed monomer is left or discarded, the environment is not destroyed. It is also possible to re-polymerize and use the decomposed monomer or the like.

  According to the invention according to claim 5 of the present invention, since it includes the thin polyester island fiber, it is excellent in various performances such as electrical insulation, separation performance, liquid retention performance, wiping performance, concealing performance, affinity, etc. It can be a thin fiber sheet. Therefore, separators for electric double layer capacitors, separators for lithium ion secondary batteries, gas or liquid filter materials, substrate materials for laminates, current collector materials, wiping materials, medical substrate materials, electrophotographic devices Can be suitably used for a fixing roll cleaning sheet.

  The sea-island fiber of the present invention is easily hydrolyzed, easy to be treated after being decomposed and removed, and can be reused for polybutylene succinate (hereinafter referred to as “PBS”), which has a low environmental impact. Some) is a sea component. Polybutylene succinate is a copolymer of 1,4-butanediol and succinic acid, but within a range that does not impair hydrolyzability, aliphatic diols other than 1,4-butanediol, fats other than succinic acid An aromatic dicarboxylic acid, an aliphatic oxycarboxylic acid, or a cyclic ester may be copolymerized.

  On the other hand, the sea-island fiber of the present invention uses, as an island component, a polyester having a mass reduction rate of 5 mass% or less under the condition that the PBS is decomposed and removed by a hydrolase. For this reason, even under the condition of decomposing and removing PBS, which is a sea component, polyester, which is an island component, is difficult to be decomposed and removed, so that it is possible to generate thin polyester island fibers having a uniform fiber diameter. The smaller the mass reduction rate, the smaller polyester island fibers with the same fiber diameter can be generated. Therefore, the mass reduction rate is preferably 1% by mass or less, and more preferably 0.1% by mass or less. The mass reduction rate may change depending on the type of hydrolase, decomposition removal conditions (temperature, time, concentration, etc.), etc., so the polyester constituting the island component cannot be limited. For example, polyethylene terephthalate, polybretin Examples thereof include aromatic polyesters such as terephthalate, polytrimethylene terephthalate, and polyethylene naphthalate, polyarolates, wholly aromatic polyesters such as liquid crystal polymers, and polycarbonates such as polycarbonate. Among these, polyethylene terephthalate and polybretin Since terephthalate or polytrimethylene terephthalate is excellent in versatility, it is preferable.

  The enzyme that hydrolyzes PBS, which is a sea component, is not particularly limited as long as it can hydrolyze and remove PBS, and examples thereof include lipase, cutinase, esterase, protease, and the like. Among these, PBS A lipase that can be easily hydrolyzed and removed is preferred. Examples of the lipase include lipase 100890 (manufactured by Seikagaku Corporation) derived from Rhizopus delemar. The hydrolase can be used in a state of being contained in an aqueous medium such as water or a buffer solution. This aqueous medium may contain a water-soluble organic solvent or a fat-soluble organic solvent, and may contain a surfactant that promotes hydrolysis, an organic substance, an inorganic substance, or the like. Furthermore, a buffering agent is added so that the pH of the aqueous medium is 3 to 12 (preferably 5 to 9, more preferably 6 to 8) so that the pH is stabilized and the hydrolase activity is high. Is preferred.

  The decomposition and removal conditions are not particularly limited as long as the PBS can be decomposed and removed. However, the temperature is preferably 25 to 150 ° C. and 40 to 100 ° C. so that the activity of the hydrolase is high. Is more preferable, and it is still more preferable that it is 40-80 degreeC. The hydrolysis removal time is not particularly limited, but the shorter the better, the better the productivity, so it is preferably 10 hours or shorter, more preferably 5 hours or shorter, and 3 hours or shorter. More preferably.

  The “mass reduction rate” in the present invention refers to the percentage of the mass reduction amount (Md) before and after hydrolysis to the mass (Mb) before hydrolysis. That is, the value is (Md / Mb) × 100.

  The fineness of the sea-island fiber of the present invention is not particularly limited, and what is important is the fineness of the polyester island fiber generated by removing the sea component PBS. ) Is preferably 3 μm or less (preferably 2 μm or less). Further, the fiber length of the sea-island fiber is not particularly limited, and may be a continuous long fiber or a cut short fiber, but a wet type capable of uniformly dispersing fine polyester island fibers. In this case, the fiber length is preferably 20 mm or less, and more preferably 0.1 to 15 mm because it is preferable to form a nonwoven fabric by the method. If the polyester island fiber formed by removing the sea component of the sea-island fiber is cut, a nonwoven fabric in which the polyester island fiber is uniformly dispersed can be produced even if the sea-island fiber is a long fiber. Also, the number of island components, the cross-sectional shape of the sea-island fiber, the cross-sectional shape of the island component, whether the diameter of the island component is one kind, or is the island component continuous in the length direction of the sea-island fiber? There is no particular limitation on how. Furthermore, the volume ratio of the sea component and the island component is not particularly limited, but since the sea component is removed, the smaller the amount, the better. Since it becomes difficult to obtain island fibers, the volume ratio of the sea component to the island component is preferably 60 to 10:40 to 90, and more preferably 50 to 20:50 to 80.

  Such a sea-island type fiber of the present invention can be produced by an ordinary composite melt spinning method or a mixed melt spinning method.

  The sea-island fiber of the present invention has the above-described configuration, but if the sea-island fiber of the present invention is used, the sea component can be removed without decomposing and removing even the polyester that is the island component. A uniform polyester island fiber can be manufactured. More specifically, an aqueous medium containing a hydrolase (preferably lipase) as described above (preferably pH is 3 to 12, temperature is preferably 25 to 150 ° C.) The fiber is immersed for 10 hours or less, and the PBS, which is a sea component, is hydrolyzed and removed to produce a thin polyester island fiber.

  The removal of the sea component from the sea-island type fiber can be performed in a fiber state such as a state where the sea-island type fiber is wound around a bobbin or the like or dispersed in an aqueous medium containing a hydrolase. It can also be carried out after forming a fiber sheet using mold fibers. However, when the sea component is removed after forming the fiber sheet, the sea component is removed to form a coarse structure fiber sheet even though it contains fine polyester island fibers. It is preferable that a thin polyester island fiber is produced by removing the fiber and a fiber sheet is formed using the polyester island fiber.

  Since the fiber sheet of the present invention contains polyester island fibers formed from the sea-island type fibers as described above, it is excellent in various performances such as electrical insulation, separation performance, liquid retention performance, wiping properties, concealment properties, and affinity. The fiber sheet can be thin. Therefore, separators for electric double layer capacitors, separators for lithium ion secondary batteries, gas or liquid filter materials, substrate materials for laminates, current collector materials, wiping materials, medical substrate materials, electrophotographic devices Can be suitably used for a fixing roll cleaning sheet.

  Examples of the fiber sheet of the present invention include woven fabrics, knitted fabrics, and non-woven fabrics. Among these, non-woven fabrics are suitable because various performances can be imparted by the production method. In particular, a wet nonwoven fabric having a thin and dense structure that can make use of the fineness of the polyester island fiber of the present invention is preferable. In addition, since content of the polyester island fiber of this invention changes with use uses, a use purpose, etc. of a fiber sheet, it does not specifically limit. Further, the fibers other than the polyester island fibers are not particularly limited because they differ depending on the use application purpose of the fiber sheet and the purpose of use.

  The fiber sheet of the present invention can be produced by a conventional method, and a suitable wet nonwoven fabric is bonded with a binder such as an emulsion or powder after forming a fiber web containing the polyester island fiber of the present invention by a conventional method. It can be manufactured by adding an adhesive fiber in the fiber web, adhering with the adhesive fiber, intertwining with a water stream, or using these together. Generally, when sea components are removed after forming a fiber sheet using sea-island type fibers, the structure becomes rough. When such a structure is allowed or preferred, the sea-island type fiber is used to form a fiber sheet. The sea component can also be removed after the formation. In addition, after forming a fiber sheet using a sea island type fiber, a sea component can be removed, and also a water stream can be made to act and densify a structure | tissue. Furthermore, the fiber sheet of the present invention can be subjected to various post treatments such as an affinity imparting treatment so as to suit various uses.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

Example 1
Polybutylene succinate (product name: AZ-71T manufactured by Mitsubishi Chemical Corporation) having a melt index (MI) of 20 at a temperature of 190 ° C. is prepared as a sea component, and an intrinsic viscosity (IV value) is prepared as an island component. 0.65 polyethylene terephthalate (manufactured by Toray Industries, Inc., product number: T-900E, lipase (manufactured by Mitsubishi Chemical Corporation, product name: GS Clear)) diluted to a concentration of 1 mass% (pH: 8, temperature: 50 ° C.) ), The mass reduction rate when immersed for 2 hours was less than 0.1 mass%).

  Subsequently, the sea component and the island component are supplied at a volume ratio of 60:40 to a sea island spinning nozzle (nozzle diameter: 0.3 mm) set to a temperature of 280 ° C. using a normal sea-island type compound melt spinning apparatus. .88 g / min. After discharging at a speed of 800 m / min. To obtain an undrawn yarn (number of islands: 25, cross-sectional shape: circular).

  Thereafter, the tow obtained by converging the undrawn yarn to a fineness of about 1000 dtex was drawn 2.8 times while passing through a warm bath at a temperature of 90 ° C., cut into 2 mm length by a guillotine cutter, and a sea island type short fiber having a fineness of 2.2 dtex. Got.

  Then, the sea-island short fibers are immersed in an aqueous solution (pH: 8, temperature: 50 ° C.) in which lipase (manufactured by Mitsubishi Chemical Co., Ltd., product name: GS clear) is diluted to a concentration of 1 mass% for about 2 hours. The component PBS was hydrolyzed and removed to produce polyethylene terephthalate short fibers (fiber length: 2 mm, cross-sectional shape: circular) with a fiber diameter of 1.8 μm. The fiber diameter CV value (= standard deviation of fiber diameter / average fiber diameter) was 6.0%.

(Comparative Example 1)
Sea-island short fibers produced in exactly the same manner as in Example 1 were immersed in an aqueous solution (pH: 14, temperature: 98 ° C.) in which sodium hydroxide was diluted to a concentration of 6 mass% for several hours. It was hydrolyzed, and the fiber diameter of the polyethylene terephthalate short fiber was not uniform without measuring the fiber diameter. Therefore, the combination of sodium hydroxide concentration and temperature is 6 mass% -60 ° C, 6 mass% -30 ° C, 3 mass% -98 ° C, 3 mass% -60 ° C, 1 mass% -98 ° C, and 1 mass% -60 ° C. In each case, the sea component and the island component were both hydrolyzed, and the fiber diameter of the polyethylene terephthalate island short fiber was not uniform.

(Comparative Example 2)
As the sea component, isophthalic acid (IPA) -modified polyethylene terephthalate (manufactured by Toray Industries, Inc., modification rate: 18 mol%) is prepared, and as the island component, polyethylene terephthalate (Toray Industries, Inc.) having an intrinsic viscosity (IV value) of 0.65 ), Product number: T-900E).

  Subsequently, the sea component and the island component are supplied at a volume ratio of 60:40 to a sea island spinning nozzle (nozzle diameter: 0.3 mm) set to a temperature of 280 ° C. using a normal sea-island type compound melt spinning apparatus. .88 g / min. After discharging at a speed of 800 m / min, undrawn yarn (number of islands: 25, cross-sectional shape: circular) was obtained.

  Thereafter, the tow obtained by converging the undrawn yarn to a fineness of about 1000 dtex was drawn 2.8 times while passing through a warm bath at a temperature of 90 ° C., cut into 2 mm length by a guillotine cutter, and a sea island type short fiber having a fineness of 2.2 dtex. Got.

  This sea-island short fiber was immersed in an aqueous solution (pH: 14, temperature: 98 ° C.) in which sodium hydroxide was diluted to a concentration of 3 mass% for several hours. Both the sea component and the island component were hydrolyzed, and the fiber Needless to measure the diameter, the fiber diameter of the polyethylene terephthalate short fibers was not uniform. Therefore, the combination of the concentration of sodium hydroxide and the temperature was tried at a combination of 3 mass% -80 ° C and 1 mass% -98 ° C. In either case, both the sea component and the island component were hydrolyzed and the fiber diameter was measured. Needless to say, the fiber diameter of the polyethylene terephthalate short fibers was not uniform.

(Comparative Example 3)
As a sea component, sulfoisophthalic acid (SIPA) modified polyethylene terephthalate (manufactured by Toray Industries, Inc., modification rate: 4.5 mol%) is prepared, and as an island component, polyethylene terephthalate having an intrinsic viscosity (IV value) of 0.65 ( Toray Industries, Inc. product number: T-900E) was prepared.

  Subsequently, the sea component and the island component are supplied at a volume ratio of 60:40 to a sea island spinning nozzle (nozzle diameter: 0.3 mm) set to a temperature of 280 ° C. using a normal sea-island type compound melt spinning apparatus. .88 g / min. After discharging at a speed of 800 m / min. To obtain an undrawn yarn (number of islands: 25, cross-sectional shape: circular).

  Thereafter, the tow obtained by converging the undrawn yarn to a fineness of about 1000 dtex was drawn 2.8 times while passing through a warm bath at a temperature of 90 ° C., cut to 2 mm length by a guillotine cutter, and a sea island type short fiber having a fineness of 2.2 dtex. Got.

This sea-island short fiber was immersed in an aqueous solution (pH: 14, temperature: 98 ° C.) in which sodium hydroxide was diluted to a concentration of 3 mass% for several hours. Both the sea component and the island component were hydrolyzed, and the fiber Needless to measure the diameter, the diameter of the polyethylene terephthalate short fibers was not uniform. Therefore, the combination of the concentration of sodium hydroxide and the temperature was tried at a combination of 3 mass% -80 ° C and 1 mass% -98 ° C. In either case, both the sea component and the island component were hydrolyzed and the fiber diameter was measured. Needless to say, the fiber diameter of the polyethylene terephthalate short fibers was not uniform.

Claims (5)

A sea-island type fiber characterized in that polybutylene succinate is used as a sea component and polyester having a mass reduction rate of 5 mass% or less is used as an island component under the condition that the polybutylene succinate is decomposed and removed by a hydrolase. The sea-island fiber according to claim 1, wherein the hydrolase is lipase. The island-in-sea fiber according to claim 1 or 2, wherein the island component is a resin component selected from polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate. The sea island type fiber according to any one of claims 1 to 3, wherein a sea component is decomposed and removed by a hydrolase. A fiber sheet comprising polyester island fibers formed from the sea-island fiber according to any one of claims 1 to 3.