JP4549237B2 - Polyketone non-woven fabric and polyketone fiber fibril - Google Patents

Description

  The present invention relates to a wet polyketone nonwoven fabric using a fibrillated product of an aliphatic polyketone fiber, a fibrillated product of an aliphatic polyketone fiber, and a method for producing the same. More specifically, high strength, high elasticity, dimensional stability, chemical resistance, heat resistance, used as a separator for separating electrodes such as core materials of printed circuit board multilayer boards, batteries, capacitors, electric double layer capacitors, The present invention relates to a uniform aliphatic polyketone non-woven fabric having excellent adhesion and electrical insulation, low water absorption, and excellent thinness and smoothness.

  Conventionally, non-woven fabric made of cellulose fiber or synthetic fiber has been used as a separator to separate the cores of printed wiring boards, batteries, capacitors, and electric double layer capacitors. Along with this, there is a demand for thinning and lamination of the core material, and there is also a demand for thinning the separators of batteries and capacitors as the size and capacity of the batteries and capacitors are increased.

  For example, in a printed wiring board, a non-woven fabric using an aromatic polyamide fiber is disclosed in Patent Document 1 and is excellent in mechanical strength, dimensional stability, heat resistance, etc., and is therefore used as a core material for multilayer printed wiring boards. Yes. However, the aromatic polyamide fiber has high water absorption, and when it is treated at a high temperature, the absorbed water is desorbed and the printed wiring board is swollen. As separators for batteries and electric double layer capacitors, in Patent Document 2, there are sheets made of fibrillated cellulose fibers, and in Patent Document 3, there are nonwoven fabrics such as polyethylene and polypropylene. In the case of non-woven fabrics such as polyethylene and polypropylene, the sheet is thick, and if it is thin, uneven dispersion becomes a problem.

A sheet-like material using polyketone fibers is disclosed in Patent Document 4, and is a sheet-like structure of 100 μm to 10 mm having low water absorption and excellent rigidity, chemical resistance, mechanical strength, dimensional stability, heat resistance, adhesiveness and the like. It is supposed to provide materials. However, in order to make the sheet thin, it is necessary to make the fiber finer, and in Patent Document 4, since the polyketone fiber is not easily fibrillated, a method of crushing by applying mechanical share to obtain the fine fiber is described. However, the fibers are entangled during crushing, so that sufficient dispersion cannot be obtained. In printed wiring boards, there are problems such as uneven core material and unevenness in separators such as batteries and electric double layer capacitors.
Japanese Patent No. 3138215 Japanese Laid-Open Patent Publication No. 10-140493 JP 10-172533 A JP 2001-207335 A

  The present invention solves the above problems found in the prior art. That is, the object of the present invention is high strength, high elasticity, dimensional stability, chemical resistance, heat resistance, adhesion, electrical insulation, low water absorption, and thin smoothness. It aims at providing a uniform aliphatic polyketone nonwoven fabric.

In order to solve the above-mentioned problems, the present inventors have focused on aliphatic polyketone fibers that are excellent in chemical resistance, heat resistance, dimensional stability, adhesiveness, and electrical insulation and have low water absorption properties. As a result of diligent study on the formation and uniform sheet formation, it has been found that a uniform aliphatic polyketone nonwoven fabric excellent in smoothness with a small thickness can be realized, and the present invention has been achieved.
That is, the first of the present invention is a fibril-like form of an aliphatic polyketone fiber comprising the repeating unit represented by the following (1), wherein the freeness of the aqueous dispersion is 25 ° SR to 60 ° SR. It is a thing.
—CH ₂ —CH ₂ —CO— (1)

The second of the invention contains a fibrillar product of the first aliphatic polyketone fiber of the invention, has a basis weight of 5 to 30 g / m ² , a thickness of 7 to 100 μm, and a density of 0.3 g / cm ^{3 to} 0. a .7g / cm ^3, a polyketone nonwoven, wherein the smoothness of 40 seconds to 300 seconds.
3rd of this invention is a polyketone nonwoven fabric characterized by air permeability resistance being 1.5 second-50 seconds.
The fourth aspect of the present invention is to preliminarily crush aliphatic polyketone short fibers having a fiber length of 1 mm to 7 mm to a freeness of 12 ° SR to 18 ° SR, and then crush to a freeness of 20 ° SR to 60 ° SR. A method for producing a fibrillar product of an aliphatic polyketone fiber.
5th of this invention is a manufacturing method of the fibril-like thing of an aliphatic polyketone fiber characterized by processing preliminary crushing with a beating machine.
A sixth aspect of the present invention is a method for producing a fibrillar product of an aliphatic polyketone fiber, wherein the crushing treatment is performed by a high-pressure homogenizer.

  The polyketone nonwoven fabric of the present invention is a uniform aliphatic having high strength, high elasticity, dimensional stability, heat resistance, chemical resistance, low water absorption, electrical insulation, excellent thickness and excellent smoothness. Polyketone non-woven fabric is provided, and there is no unevenness such as printed wiring board core material, and the separator is uniform and thin in batteries, capacitors and electric double layer capacitors, etc. Has an effect.

Hereinafter, the present invention will be specifically described.
The present invention is a wet polyketone nonwoven fabric containing fibrillated aliphatic polyketone fiber fibrillar material, utilizing the property that the aliphatic polyketone fiber rapidly softens and deforms near the melting point. It is characterized by exhibiting strength by heat fusion. Therefore, even if it is thin and porous, it can be made into a uniform and tough nonwoven fabric with excellent smoothness.
The fibrillar product of the aliphatic polyketone fiber used in the present invention preferably has a freeness of the aqueous dispersion of 20 ° SR to 60 ° SR. The freeness was determined by using a shopper freeness tester according to JIS-P8121, diluted to water so that the fiber concentration was 0.2% by mass (relative to the absolute dry weight), and the average value measured twice.

  The aliphatic polyketone fiber used in the present invention is preferable because it can be uniformly crushed by cutting the fiber length to 1 mm to 7 mm before preliminary crushing with a beater, preferably a beater or refiner. Moreover, in order to prevent the occurrence of fiber clogging with a high-pressure homogenizer, the freeness can be preliminarily crushed to 12 ° SR to 18 ° SR, preferably 12 ° SR to 15 ° SR with a beater, preferably a beater or refiner. preferable. The pre-crushing concentration in the beater is preferably 0.5% to 2% by weight for a beater and 0.5% to 10% by weight for a refiner. Occurrence of clogging is prevented, and efficient processing is possible without crushed fibers. The crushing strength, time, and number of treatments during crushing by the beating machine can be appropriately adjusted so that the freeness of the fiber after crushing is in the range of 12 ° SR to 18 ° SR. Further, it is preferable to add an antifoaming agent and a dispersing agent as appropriate, since crushing can be efficiently performed with a beating machine.

When the polyketone fiber of the present invention is crushed with a high-pressure homogenizer, the concentration is preferably 0.1% by mass to 2% by mass in order to prevent generation of fibers and to perform an efficient treatment. The treatment pressure of the high-pressure homogenizer is preferably 50 MPa to 150 MPa, and in order to obtain fibrils having an extremely small fiber diameter, it is preferable to appropriately adjust the number of treatments so that the freeness is 20 ° SR to 60 ° SR. More preferably filtration freeness 20 ° SR~50 ° SR, more preferably from filtrate freeness 25 ° SR~50 ° SR. The fibrillar product of the aliphatic polyketone fiber obtained by the crushing process is free from agglomeration due to the entanglement of fibers, and a smooth and uniform nonwoven fabric can be produced.

It is preferable that the polyketone nonwoven fabric containing the fibrillar product of the aliphatic polyketone fiber of the present invention has a basis weight of 5 to 30 g / m ² . By setting the basis weight within this range, it is possible to obtain a nonwoven fabric having strength even when thin and having good air permeability. Moreover, it is preferable that the thickness of a polyketone nonwoven fabric is 7-100 micrometers. Good breathability, obtained a liquid permeable, and in order to obtain the strength, it is preferable to set the density of the nonwoven fabric and ^{0.3g / cm 3 ~0.7g / cm 3} . The smoothness of the polyketone nonwoven fabric of the present invention is preferably 40 seconds to 300 seconds, since there is no unevenness in strength and a uniform sheet can be formed. The smoothness is more preferably 40 seconds to 200 seconds. The smoothness was defined as an average of five measurements each for the front and back of the nonwoven fabric using a smoothness test method using a Beck smoothness tester in JIS-P8119.

  By setting the air resistance of the non-woven fabric made of the fibril-like material of the aliphatic polyketone fiber of the present invention to 1.5 to 50 seconds, it is possible to perform good resin impregnation as a printed circuit board application, This is preferable because of its good permeability. The air resistance is more preferably 1.5 seconds to 40 seconds. The air resistance was defined as an average of five measurements using the air permeability test method according to the Gurley tester method in JIS-P8117.

The aliphatic polyketone fiber used in the present invention has a structure in which the repeating unit represented by the following (1) is 90 mol% or more. When it is 90 mol% or more, high strength and high elasticity can be obtained, and heat resistance is also excellent. Further, the crystallinity of the fiber is preferably 30% or more. When it is 30% or more, high strength and high elasticity are exhibited. The polyketone fiber is preferably obtained by a wet spinning method from a polyketone aqueous solution using zinc salt, calcium salt, isocyanate salt, etc., and then hot stretched to produce a polyketone fiber having high strength and high elasticity. .
—CH ₂ —CH ₂ —CO— (1)

  The polyketone nonwoven fabric containing the fibrillar product of the aliphatic polyketone fiber of the present invention can be produced by a wet papermaking method. Aliphatic polyketone fibers and / or fibrils of aliphatic polyketone fibers are uniformly dispersed in water by a disaggregator, then a circular paper machine, a long paper machine, a slanted short paper machine, or a combination thereof Paper making is performed with a paper machine or the like, and a paper layer in which the fibers are uniformly dispersed in a planar shape is formed on a net. As additives for papermaking, it is possible to add stickiness agents such as polyacrylamide and polyethylene oxide, and paper strength enhancers such as water-soluble epoxy resins and epoxy-modified polyamides. Moreover, the workability | operativity of papermaking can be improved by adding an antifoamer and a dispersing agent suitably. The polyketone nonwoven fabric containing the fibrillar product of the aliphatic polyketone fiber of the present invention is sufficiently dried with a dryer such as a drum dryer, a Yankee dryer, or a hot air dryer after paper making, and then the paper is obtained by fusing the fibers with a hot roll press or the like. The final strength of can be expressed.

  In order to thermally fuse all or part of the aliphatic polyketone fibers, it is preferable to heat press at a melting point temperature of the polyketone fibers of −40 ° C. to + 40 ° C. The polyketone fiber is thermally fused at a melting point temperature of −40 ° C. or higher. Further, it is preferable that the melting point is not higher than + 40 ° C. without causing melting and seizure. The press linear pressure at the time of hot pressing can be carried out within a known range, but is preferably 1 to 200 kN / m in order to control the thickness.

The polyketone nonwoven fabric containing the fibrillar product of the aliphatic polyketone fiber of the present invention can be washed with an acid, an alkali, an organic solvent or the like after the strength is expressed by hot pressing.
The polyketone nonwoven fabric containing the fibrillated product of the aliphatic polyketone fiber according to the present invention is further improved in strength by impregnating or applying a thermoplastic resin or a polymer resin such as a thermosetting resin, or has a workability and other functions. Can be granted.

  The present invention will be described based on examples, but the present invention is not limited to these examples. Table 1 shows the constituent requirements and characteristic measurement results of the nonwoven fabric.

[Example 1]
An antifoaming agent was added to 100% by mass of an aliphatic polyketone short fiber having an average fiber diameter of 10 μm and a fiber length of 3 mm, and was dispersed in water with a high-speed disintegrator to prepare a fiber dispersion. The fiber dispersion was preliminarily crushed using a beater at a concentration of 0.5 mass% until the freeness became 13 ° SR. Further, it was treated with a high-pressure homogenizer (manufactured by Niro Soabi) at a pressure of 100 MPa, and crushed to a freeness of 39 ° SR to obtain a fibrillar product of aliphatic polyketone fibers. A sticky agent was added to the fibrillar product of the aliphatic polyketone fiber thus obtained, vacuum deaeration was performed immediately before papermaking, and a basis weight of 10 g / m ² was obtained with a circular paper machine equipped with a 100 mesh papermaking net. And then dried with a Yankee dryer having a surface temperature of 130 ° C. and then hot-pressed with a hot press roll having a surface temperature of 250 ° C. at a hot press linear pressure of 20 kN / m to obtain a nonwoven fabric having a thickness of 22 μm.
The non-woven fabric thus produced had a smoothness of 80 seconds and an air resistance of 20 seconds.

Further, even when the nonwoven fabric was stored at 230 ° C. for 3 hours, the nonwoven fabric did not turn yellow and remained constant without changing dimensions, and had good heat resistance and dimensional stability. Moreover, even when immersed in 40% sulfuric acid, 40% aqueous sodium hydroxide solution, and hexane at room temperature for 1 day, there was no change and the chemical resistance was good. Furthermore, even when the nonwoven fabric was stored at a temperature of 23 ° C. and a relative humidity of 80% for 3 days, the water absorption was less than 1% by mass and the water absorption was low. Moreover, after impregnating this nonwoven fabric with machine oil ISOVG10 prescribed | regulated to JIS- K- 2238, the excess oil on the surface was wiped off and the translucent film | membrane was obtained. Using this semitransparent film, machine oil impregnation unevenness was visually evaluated. A case where a uniform translucent film having no impregnation unevenness was obtained, ○, a part where there was uneven impregnation and spotted cloudiness in the translucent film, Δ, a part of impregnation unevenness and a fiber agglomerated portion was seen. What was made was set as x. Next, five semi-transparent films were stacked, and the degree of adhesion after pressing was visually evaluated. The case where the adhesion was good and there were no voids between the semi-transparent films was marked with ◯, the case where the adhesion was insufficient and the voids were slightly seen, and the case where the adhesion was poor and many voids were seen. The results are shown in Table 1.

[Examples 2 to 4]
A non-woven fabric of aliphatic polyketone fiber fibrillated product was obtained using the same production method as in Example 1. The parts with different conditions in the manufacturing method are shown in Table 1.

[Comparative Example 1]
An antifoaming agent was added to 100% by mass of aliphatic polyketone short fibers having an average fiber diameter of 10 μm and a fiber length of 3 mm, and the mixture was dispersed in water with a high-speed disintegrator to prepare a fiber dispersion. The fiber dispersion was concentrated to 0.5% by mass using a beater and preliminarily crushed to a freeness of 10 ° SR to obtain polyketone fiber fibrils. Furthermore, the treatment was attempted at a pressure of 100 MPa with a high-pressure homogenizer (manufactured by Niro Soabi), but could not be treated due to fiber clogging. Therefore, a pre-crushed aliphatic polyketone fiber fibril is added with a sticky agent, vacuum degassed immediately before paper making, and a basis weight of 35 g / m ² with a circular paper machine equipped with a 100 mesh paper machine. And then dried with a Yankee dryer having a surface temperature of 130 ° C., and then hot pressed with a hot press roll having a surface temperature of 260 ° C. at a hot press linear pressure of 20 kN / m, to obtain a nonwoven fabric having a thickness of 137 μm. The smoothness of the nonwoven fabric produced in this way was 2 seconds, and the air resistance was less than 1 second.

[Comparative Examples 2 to 4]
Using the same production method as in Comparative Example 1, nonwoven fabrics using aliphatic polyketone fibers shown in Table 1 were obtained. The parts with different conditions in the manufacturing method are shown in Table 1.
The nonwoven fabrics produced in Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated and compared. The results are shown in Table 1.

  The polyketone nonwoven fabric of the present invention is an electrode for a battery such as a core material for printed wiring boards, an aluminum electrolytic capacitor, or an electrode separator for separators such as an electric double layer capacitor, or a separator core material, a fuel cell, a lithium ion battery, or a nickel-hydrogen battery. It can be suitably used for applications such as a separator, a separator core material, and a core material for an ion exchange membrane.

Claims (3)

After preliminarily crushing an aqueous dispersion of aliphatic polyketone short fibers having a fiber length of 1 mm to 7 mm, comprising repeating units represented by the following (1) to a freeness of 12 ° SR to 18 ° SR, the freeness of 20 ° SR A process for producing a fibrillar product of aliphatic polyketone fiber, characterized by crushing to ˜60 ° SR.
—CH ₂ —CH ₂ —CO— (1) The method for producing a fibrillar product of aliphatic polyketone fiber according to claim 1 , wherein the preliminary crushing is processed by a beater. The method for producing a fibrillar product of aliphatic polyketone fiber according to claim 1 , wherein the crushing treatment is performed by a high-pressure homogenizer.