JP2008202194A - Ultra fine filament nonwoven fabric and method for producing ultra fine filament nonwoven fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an ultra fine filament nonwoven fabric which has good antistaticity, has an improved uniform opening property in a sheet-forming process, prevents the generation of static electricity in a post process, and can easily be peeled and split by a mechanical impact treatment in a splitting process. <P>SOLUTION: This method for producing the ultra fine filament nonwoven fabric including finely splitting peel-split type conjugated fibers composed of a polyamide-based polymer and a polyester-based polymer, includes adding 0.3 to 3.0 wt.% of a polyalkylene glycol and 0.5 to 3.0 wt.% of an organic metal salt represented by formula: R-SO<SB>3</SB>M to at least one of the polymers to produce the peel-split type conjugated fibers, producing a nonwoven fabric from the peel-splitting type conjugated fibers, and then subjecting the nonwoven fabric to a splitting treatment in the presence of water. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a method for producing an ultra-thin fiber nonwoven fabric obtained by splitting a separation-dividing composite fiber composed of a polyamide polymer and a polyester polymer, and the ultra-fine fiber nonwoven fabric. More specifically, the present invention relates to process stability such as charging property and spinning stability and improvement of splitting properties when manufacturing an ultra-thin fiber non-woven fabric obtained by splitting the release split composite fiber.

Conventionally, a method for producing an ultrafine fiber nonwoven fabric includes a method of eluting and removing one polymer component of a composite fiber composed of a plurality of types of polymer polymers, or applying a mechanical external force to a peel-off split composite fiber to provide an ultrafine fiber. A method of manufacturing a nonwoven fabric by dividing into fibers is known.
In particular, a method of making a non-woven fabric obtained by combining a two-component bonded release split composite fiber (hereinafter simply abbreviated as a split split composite fiber) with a spunbond method into an ultrafine fiber without eluting one polymer component. Is an excellent method in terms of energy costs and environmental considerations.

  In this direct-spun type spunbond method, the spun peelable split composite fibers can be opened as uniformly as possible, and the local entanglement between the fibers can be reduced and collected in a sheet form to form a uniform nonwoven fabric. It is essential in manufacturing. However, the split-divided composite fiber made of a high molecular polymer generates a lot of static electricity during yarn production, and it is extremely difficult to spread it uniformly in the sheet forming process. Conventionally, a method of treating the traveling fiber by providing a special device such as a corona discharge device or a contact charging device has been adopted, but it has not yet been achieved to achieve uniform opening by suppressing static electricity It is.

  Various trials have also been proposed regarding a method for splitting a split split composite fiber and a method for improving the split rate. For example, in JP-A-4-300311, JP-A-10-53948, etc., a long-fiber non-woven fabric made of a peelable split composite fiber is treated with a high-pressure water flow machine to convert the split splittable composite fiber into an ultrafine fiber. A method has been proposed in which an ultrafine fiber nonwoven fabric is obtained by peeling and dividing. However, these mechanical methods alone are not easy to divide, but the problem is that fiber unevenness is likely to occur, and it is difficult to obtain a uniform nonwoven fabric, and a special high-pressure columnar water flow is required. In this case, it is difficult to divide the water flow because it does not reach the center of the nonwoven fabric thickness.

  As an attempt to improve the splitting property of the peelable split composite fiber, for example, JP-A-5-331758 includes a polyalkylene glycol in one component of the split splittable composite fiber composed of a polyester component, and the composite fiber. There has been proposed a method in which a mechanical stress is applied to a nonwoven fabric to be made into ultrafine fibers by separation and separation. However, this method has a problem in that the physical properties of the fiber are lowered because it is necessary to contain a large amount of polyalkylene glycols of several tens of percent with respect to the polymer in order to sufficiently exhibit the separation of peeling.

  In view of the above problems, the present inventors have specified the ratio of polyamide occupying the outer periphery of the peelable split fibers in Japanese Unexamined Patent Publication No. 2003-3359 in the long-fiber nonwoven fabric made of peelable split fibers made of polyester and polyamide. In addition, a method has been proposed in which at least one polymer contains 0.3 to 3.0% by weight of polyalkylene glycols to improve the spreadability and splitting ability. However, in the dry winter season, a large amount of static electricity is generated when the sheet is split and transported after the nonwoven fabric process, and when the sheet is unwound and unwound. However, the current situation is that the stability of the process is remarkably hindered, and it cannot be said that the separability is sufficient, and further improvement is necessary.

  In this way, the antistatic property is good, the uniform spreadability in the sheeting process is good, the generation of static electricity in the subsequent process is prevented, and the film is easily separated and divided by mechanical impact treatment in the dividing process. There has been a great demand for the development of a method for producing an ultra-thin fiber non-woven fabric using a peelable split composite fiber.

JP-A-4-30031 JP-A-10-53948 JP-A-5-331758 JP 2003-3359 A

  The present invention has been made against the background of the above-described prior art, has good antistatic properties, improved uniform spreadability in the sheeting process, prevents generation of static electricity in the subsequent process, and machine in the dividing process. Provided is a method for producing an ultra-thin long fiber nonwoven fabric that can be easily separated by mechanical impact treatment.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have produced a method for producing an ultra-thin fiber non-woven fabric obtained by splitting ultrafine release split composite fibers composed of a polyamide polymer and a polyester polymer. In which at least one polymer contains 0.3 to 3.0% by weight of a polyalkylene glycol and 0.5 to 3.0% by weight of an organometallic salt represented by RSO ₃ M A composite fiber is formed, and after being made into a nonwoven fabric, it is divided in the presence of water.

According to the present invention, in the production process of an ultra-thin fiber non-woven fabric obtained by splitting ultrafine separation-type composite fibers composed of a polyamide-based polymer and a polyester-based polymer, at least one fiber component contains polyalkylene glycols and R- The presence of a specific amount of the organic metal salt represented by SO ₃ M improves the process stability based on the spinning stability and antistatic property, and has an unexpectedly great effect on the separation of the separation. Quality and quality ultra-fine fiber nonwoven fabric can be obtained.

Hereinafter, embodiments of the present invention will be described in detail.
The release-dividing composite fiber used in the present invention is not particularly limited as long as it is composed of a fiber-forming polyester polymer and a fiber-forming polyamide-based polymer and can be separated into each component by mechanical treatment or the like. . Examples of polyamide polymers that are preferably used include nylon-6, nylon-66, nylon-610, nylon-11, nylon-12, and the like. On the other hand, examples of the polyester-based polymer include polyethylene terephthalate, polytriethylene terephthalate, polybutylene terephthalate, and copolymer polyesters containing these as main components. Among these, a combination of nylon-6 / polyethylene terephthalate is preferable from the viewpoints of production stability and cost.

  As the composite form of the peelable split type composite fiber, at least a part of the joint interface between the polyester polymer and the polyamide polymer has reached the circumference of the fiber cross section and can be peeled and split into each component by mechanical treatment or the like It is necessary to become. In addition, it is desirable from the viewpoint of the separation property that one component is divided into a predetermined number by the other component. Among these, a cross-sectional shape in which one component is arranged radially between other components is preferable. Such a composite form can be obtained by, for example, composite spinning a polyester polymer and a polyamide polymer using a composite spinneret described in JP-A-54-38914.

  In the present invention, the ratio of the arc length (A) of the polyamide polymer to the arc length (B) of the polyester polymer occupying the fiber cross-section circumference (hereinafter referred to as polymer component arc length ratio (A / B)). It is desirable to arrange the two components so that is in the range of 0.1 to 2.0, more preferably in the range of 0.2 to 1.5.

  When the polymer component arc length ratio (A / B) exceeds 2.0, the opening property is significantly lowered, and the nonwoven fabric weight and the strength are reduced. It is presumed that the polyamide-based polymer has a relatively low glass transition point, is slow to solidify, easily adsorbs moisture, and the fibers tend to adhere to each other, resulting in poor opening. On the other hand, when the polymer component arc length ratio (A / B) is less than 0.1, the external stress is not sufficiently applied to the two-component bonding interface during the separation process, and the separation process becomes difficult.

  The arc length of each polymer component can be arbitrarily set by changing the method of joining the polymer components in the composite spinneret, the weight ratio, or the viscosity ratio at the confluence portion in the die. In particular, by setting the melt temperature (hereinafter referred to as the conduit polymer temperature) immediately before the melt-extruded polymer flows into the spin block, the melt viscosity of each polymer is changed, and the polymer component arc length is changed. A method of setting the ratio (A / B) is simple and preferable.

  The number of divisions of the peeled-divided composite fibers in which the components are arranged in this way can be arbitrarily set by a method in which the two components are melted and merged in the spinneret. Considering the single yarn fineness of the composite fiber that can be stably spun, it is desirable to set the number of divisions to 4 to 48, more preferably 8 to 24.

  In addition, if the composite ratio with respect to the whole of one component of the peelable split type composite fiber is in the range of 30 to 70% by weight, particularly in the range of 40 to 60% by weight, the spinning process becomes more stable and the cross section of the cross section is stabilized. Type composite fiber is suitable. When outside this range, it is difficult to adjust the viscosity balance of both polymers, section defects during spinning are likely to occur, and the separation efficiency is liable to decrease.

  The cross-sectional shape of the whole peelable conjugate fiber is arbitrary, such as a round cross-sectional shape, a multi-leaf cross-sectional shape, and a polygonal shape, and may have a hollow portion. In the case of a cross-sectional shape having a hollow part, the length of the two-component bonding interface is shortened, so that the separation of separation is further improved.

Further, in the present invention, at least one component of the two-component polymer is 0.3 to 3.0% by weight, preferably 0.5 to 2.0% by weight of polyalkylene glycols before opening. It must be contained 0.5 to 3.0% by weight of organic metal salts represented by R-SO ₃ M with the inclusion of.

By blending polyalkylene glycols with at least one polymer, a great deal of static electricity generated when the spinning process is thinned and when fibers are collected is greatly suppressed, and the fibers are captured in a web-like form in a uniform open state. Can be collected. However, the addition of polyalkylene glycols is not sufficient for the effect of suppressing static electricity, and in the present invention, static electricity is remarkably suppressed by adding together an organometallic salt represented by R-SO ₃ M. The organometallic salt represented by R—SO ₃ M is known to have an antistatic effect, and it is within the expectation that the addition of this can prevent the non-woven fabric from being charged. It is an effect beyond expectation that the splitting property is greatly improved together with the antistatic property by coexisting the organic metal salt represented by R-SO ₃ M with the alkenyl group. By using polyalkylene glycols, the interfacial releasability of polyamide and polyester components is improved. However, the coexistence of an organometallic salt represented by R—SO ₃ M facilitates interfacial exfoliation as a synergistic effect, resulting in separation. Improves sex. In particular, when a mechanical stress is applied in the presence of water, good splitting properties are exhibited. Although the reason for this is not clear, not only the affinity between the fiber polymer and water by the organometallic salt represented by the highly polar R-SO ₃ M is improved, but also polyarylene in the fiber polymer. It is considered that the dispersibility of glycols is improved, and the probability of existence of polyalkylene glycol particles that facilitate interfacial peeling at the polyester / nylon interface is increased, thereby greatly improving the resolution.

  When the amount of polyalkylene glycol added is less than 0.3% by weight, there is no static electricity suppressing effect, the component peeling effect is lost, and separation of the two components becomes difficult. When the addition amount of polyalkylene glycol exceeds 3.0% by weight, or when the addition amount of organometallic salt exceeds 3.0% by weight, the viscosity of the polymer to be added is lowered and spinning becomes difficult, and the polymer Problems such as deterioration of the physical properties of the non-woven fabric due to fibrillation occur.

  Examples of the polyalkylene glycols used in the present invention include polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol, ethylene oxide / propylene oxide block, and random copolymer. These may be blocked with an alkyl group, an aryl group, an acyl group or the like, or may be a block polyether ester or a block polyether amide obtained by reacting various glycol components, amine components, and acid components. Among these, those whose ends are blocked with an alkyl group are more preferable because light resistance is improved.

  Polyalkylene glycols having an average molecular weight of 2000 to 600000 can be used. Those having an average molecular weight of 4,000 to 100,000, particularly 5,000 to 50,000 are easily available, and are preferable because they have good spinning stability.

As the organic metal salt, a sulfonic acid metal salt represented by R—SO ₃ M is preferably used. Here, R is an alkyl group having 8 to 15 carbon atoms, M is an alkali metal or an alkaline earth metal, and among these, Na is preferable. Examples include dodecyl benzene sulfonic acid, tridecyl benzene sulfonic acid, nonyl benzene sulfonic acid, dibutyl naphthalene sulfonic acid, hexadecyl sulfonic acid, and dodecyl sulfonic acid, and other alkali metal salts of phosphate esters such as sodium distearyl phosphate. Etc. are also preferably used. The organometallic salt may be used alone or in combination of two or more. The blending amount is preferably in the range of 0.5 to 3% by weight.

  The polyalkylene glycols and organometallic salts are added to each fiber-forming polymer by a method of adding them in the polymerization step of the component-forming polymer, and when the composite fiber is melt-spun, the fiber-forming polymer and the polyalkylene glycols are added. Adopting any method such as a method of melt kneading after mixing the organic metal salt and a method of kneading the melted fiber-forming polymer, polyalkylene glycols and organic metal salt before melt spinning Can do. Among them, fiber spinning polymer chips, polyalkylene glycols and organometallic salts are mixed and melt-spun from the viewpoints of heat resistance of polyalkylene glycols and organometallic salts and ease of melt spinning. The method to do is desirable.

  Next, the peelable split type composite fibers discharged from the spinneret are indexed and refined at a speed of 1500 to 8000 m / min, more preferably 2000 to 6000 m / min, by a high-speed traction fluid such as an ejector or air soccer, and opened. The fiber is collected on the porous collecting surface while being finely wound and wound up as a web-like sheet. At that time, if treatment such as corona discharge or contact charging is performed, the spreadability is further improved.

  The nonwoven fabric of the composite fiber obtained in this manner is laminated as needed, or alone, thermally bonded as necessary, once wound up, or continuously after needle punching, etc. The entanglement process is applied to the separation separation process.

  The separation method is not particularly limited as long as the separation and separation of components can be reliably performed, and a plurality of methods may be combined. For example, examples of the mechanical separation and division method include a method of applying pressure between rollers, an ultrasonic treatment method, an impact applying method, and a stagnation treatment method. Among these, the method using a sheet-like object striking type grinder is the most effective and preferable. In addition, the sheet-like object striking-type squeezing machine here can efficiently apply a shearing force in the thickness direction of the sheet. This method can efficiently perform the separation and division of the separation-dividing composite fiber.

  In the present invention, prior to the split ultrafine fiber processing of the above split split composite fiber, it is preferable that the long fiber nonwoven fabric is preliminarily given water and then split in the presence of water. Here, the water to be applied may be mixed with a chemical that swells at least one component of the separation-divided fiber, and the application method may be a conventionally known method such as immersion in water. Good. However, in the case of aiming at densification or the like, it is preferable to perform shrinkage heat treatment subsequent to the division treatment, so it is preferable to avoid a division treatment method in which heat is applied before fiber division is performed.

  The range of 0.01 to 0.60 dtex is appropriate for the single yarn fineness after the separation treatment. Those having a thickness of less than 0.01 dtex tend to be difficult to separate by peeling, or the fibers after the separation and separation are so thin that sticking occurs between the fibers. On the other hand, if it exceeds 0.60 dtex, the fiber is too thick, making it difficult to obtain a uniform and fine nonwoven fabric.

  Such fine fineness after separation by separation is determined from the single yarn fineness and the number of component divisions of the separation-division type composite fiber. The single yarn fineness of the peelable split composite fiber is preferably 1 to 10 dtex. If the single yarn fineness of the peelable split composite fiber is less than 1 dtex, yarn breakage is likely to occur during spinning. If the single yarn fineness of the peelable split composite fiber is greater than 10 dtex, it becomes difficult to make the fineness after the peel splitting finer.

  The obtained non-woven fabric can be used for artificial leather base fabrics, clothing, interior materials, interior materials and other industrial materials, industrial wipers and wipes such as wipes, bag filters and filter cloths, medical It can be preferably used for applications such as sanitary materials.

Hereinafter, the present invention will be described more specifically with reference to examples.
In addition, each item in an Example was measured with the following method.
(1) Division ratio The cross section of the nonwoven fabric was photographed at 200 times with an electron microscope, the cross-sectional area of 50 fibers was measured, and the entire area and undivided (not completely separated by separation, such as 2 The difference in the cross-sectional area of the fibers (including those separated and divided into about three) was divided by the total area.
(2) Single yarn fineness after splitting The composite fiber immediately after being spun from the base and pulled at high speed by an air flow is sampled, and a test length 2 using a fineness measuring instrument (SERCH CO. LTD, model DC-21). Measured at 0.5 cm and a load of 0.3 g, the composite fiber fineness was determined from the 10 average single yarn finenesses, and calculated by the following formula.
Single yarn fineness after division = average single yarn fineness of composite fiber / number of divisions / (exfoliation division ratio / 100)
(3) Spinnability Nonwoven fabric was produced continuously for 3 days, and the discharge stability from the die at that time was evaluated as follows.
○: Good without problems △: Foreign matter adhesion around the discharge hole is observed, and single yarn breakage sometimes occurs ×: A large amount of foreign matter adheres around the discharge hole, causing bending, and single yarn Cut frequently.
(4) Amount of static electricity generated by high-speed traction by air flow, immediately after being deposited on the collection net, after thermal bonding, before unwinding with a winder, and after 3000 m is unwound after 2 hours The amount of static electricity on the surface of the non-woven fabric was measured with an electrostatic potential measuring device (STATIRON DZ3 manufactured by Sisid Electric Co., Ltd.).
(5) Opening property: evaluated by non-woven fabric weight spot (CV%) The non-woven fabric is cut into small pieces having a width of 2 cm and a length of 20 cm so that the width is in the width direction of the non-woven fabric, and the weight is measured. What was divided by the average value of was expressed in% as non-woven fabric weight spots.

[Example 1]
Polyethylene glycol (manufactured by Nippon Oil & Fats Co., Ltd.) having a molecular weight of 20,000 and 2.0% by weight of sodium dodecylbenzenesulfonate with respect to nylon-6 (intrinsic viscosity 1.2 in m-cresol) dried at 120 ° C. % Blended mixture was fed to an extruder and melted. Separately dried polyethylene terephthalate (at an intrinsic viscosity of 0.64 in o-chlorophenol) at 160 ° C. was melted with an extruder separate from the foregoing.

  Subsequently, the polyethylene glycol / organometallic salt / nylon-6 mixture melt flow was introduced into a spin block maintained at 275 ° C. at a conduit polymer temperature of 245 ° C. and a polyethylene terephthalate melt flow at 300 ° C. No. 38914 and a rectangular spinneret having 3200 round cross-section discharge holes in a grid arrangement in a range of 100 cm × 20 cm in width, the both polymer melt flows at a flow rate ratio of 50 / 50 g of air and a 120 cm wide slit, air pressure of 230 kPa (spinning speed converted from the discharge rate and fineness of the composite fiber, about 3200 m / min) Towed at high speed.

  The fineness of the pulled composite fiber is 1 m wide on the net conveyor as a web of peeled split composite fibers having a 16-layer multi-layer laminated cross section as shown in FIG. Opened and collected. Subsequently, the obtained web was passed through a pair of upper and lower embossed calender rolls heated to 100 ° C. and thermally bonded.

The single yarn fineness of the composite fiber was 3.1 dtex, and the nylon-6 component and the polyethylene terephthalate were separated from each other by 16 parts by the partner component. The polymer component arc length ratio (A / B) was 0.70.
The resulting web is entangled with a needle punch, then immersed in water, lightly squeezed with a mangle, and then subjected to a separation-splitting treatment with a sheet-like material strike-type squeezing machine, and an ultrafine fiber nonwoven fabric having a basis weight of 150 g / m ² Got. Table 1 shows a summary of the implementation conditions and the results obtained in this example.

[Example 2]
A blend of 0.7% by weight of polytrimethylene glycol having a molecular weight of 25000 and 0.5% by weight of sodium dodecylbenzenesulfonate to nylon-6 (intrinsic viscosity 1.2 in m-cresol) dried at 120 ° C. The resulting mixture was fed to an extruder and melted. Separately dried polyethylene terephthalate (1602 intrinsic viscosity in o-chlorophenol) was melted with an extruder separate from the above.

Thereafter, discharging, high-speed traction, collection, thermal bonding, entanglement treatment, and separation / separation treatment were performed under the same conditions and methods as in Example 1 to obtain an ultrafine fiber nonwoven fabric having a basis weight of 150 g / m ² .
The single yarn fineness of the composite fiber was 3.1 dtex, and both components were divided into 16 layers by the other component. The polymer component arc length ratio (A / B) was 2.0.
Table 1 shows a summary of the implementation conditions and the results obtained in this example.

[Comparative Examples 1-5]
An ultrafine fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the addition amounts of polyethylene glycol and organic metal salt were changed.
Table 1 shows a summary of the implementation conditions and the results obtained in this example.

  As shown in Table 1, the non-woven fabrics obtained in Examples 1 and 2 within the scope of the present invention showed good spinnability and splitting properties, and generated little static electricity and excellent fabric uniformity. On the other hand, in Comparative Examples 1 to 5 in which the addition amount of the polyalkylene glycol and the organic metal salt is out of the range of the present invention, the spinnability or splitting property is poor. In Comparative Examples 2 and 3 where the addition amount of the organic metal salt was particularly small, there was a problem in process stability, for example, the amount of static electricity generated was large and wrinkles were generated when the fabric wound with the winder was released. In Example 1 and Comparative Examples 4 and 5, even though the total addition amount is almost the same, the division ratio is much better in Example 1 and it can be said that it is a synergistic effect due to the coexistence of both.

  Non-woven fabrics of the present invention are used for artificial leather base fabrics and clothing, industrial materials such as interior materials and interior materials, wipers such as industrial wipers and wiping cloth, uses such as filters such as bag filters and filter cloths, medical It can be preferably used for applications such as sanitary materials.

The schematic diagram which showed the fiber cross section of the peeling division | segmentation type | mold composite fiber of this invention.

Explanation of symbols

1: Polyamide polymer component 2: Polyester polymer component

Claims (4)

In the method for producing an ultra-thin fiber non-woven fabric obtained by splitting a separation-dividing composite fiber composed of a polyamide-based polymer and a polyester-based polymer, a polyalkylene glycol is added in an amount of 0.3 to 0.3 in at least one polymer. A release split type composite fiber containing 3.0 wt% and an organometallic salt represented by R—SO ₃ M in an amount of 0.5 to 3.0 wt% is made into a long fiber nonwoven fabric and split in the presence of water. A method for producing an ultra-fine long-fiber nonwoven fabric characterized by the following.
(Here, R is an alkyl group having 8 to 15 carbon atoms, and M is an alkali metal or alkaline earth metal.)   The method for producing an ultra-fine long-fiber non-woven fabric according to claim 1, wherein the single yarn fineness after making the ultra-fine fiber is 0.01 to 0.60 dtex. An ultra-thin fiber non-woven fabric obtained by dividing a separation-dividing composite fiber composed of a polyamide-based polymer and a polyester-based polymer, wherein polyalkylene glycols are contained in at least one polymer of the separation-dividing composite fiber An ultra-fine fiber nonwoven fabric characterized by containing 0.3 to 3.0% by weight and an organic metal salt represented by R-SO ₃ M in an amount of 0.5 to 3.0% by weight.
(Here, R is an alkyl group having 8 to 15 carbon atoms, and M is an alkali metal or alkaline earth metal.) In a long-fiber nonwoven fabric composed of a release-divided composite fiber composed of a polyamide polymer and a polyester polymer, 0.3 to 3.0% by weight of polyalkylene glycols and R in at least one polymer long-fiber nonwoven fabric, characterized in that it contains an organic metal salt represented by -SO ₃ M 0.5 to 3.0 wt%.
(Here, R is an alkyl group having 8 to 15 carbon atoms, and M is an alkali metal or alkaline earth metal.)

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