JPH07776A - Polyketone porous film and production thereof - Google Patents

Abstract

PURPOSE:To obtain a film excellent in heat resistance, pressure resistance and chemical resistance by mixing a specific quantity of fine particles having a specific particle diameter with a polyketone polymer to make a polyketone porous film having slit like fine narrow pores. CONSTITUTION:The polyketone polymer of 40-95wt.% and the fine particles such as calcium carbonate, crosslinked silicone resin of 60-5wt.% having 0.02-10mum average particle diameter are mixed. And by stretching the mixture, the polyketone porous film having the fine narrow pores penetrating in the thickness direction of the porous film and composed of the slit like fine pores having 0.01-10mum average width is obtained. The film obtained in this way has resistance against steam sterilization or high temp. treatment.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyketone porous membrane used for microfiltration and a method for producing the same.

[0002]

2. Description of the Related Art Porous membranes are used for microfiltration in a wide range of fields such as industrial fields such as industrial wastewater / process water treatment, medical fields such as artificial kidney / plasma separation, food-related fields and household water purifiers. There is.

Various methods are known as a method for producing a porous film used for such purposes, for example, a micro-phase separation wet method, an additive extraction method, a post-irradiation etching method, a melt shaping drawing method. Etc. Among these, the method of making it porous by the melt-shaped drawing method is relatively simple, and since it does not use a solvent, it is excellent in safety.

As the melt-shaped drawing method, a method of forming fine through-holes by separating lamella laminated crystal parts of a crystalline polymer (Japanese Patent Publication No. 56-52123 and Japanese Patent Publication No. 57-42919). ), A method of forming fine through holes by adding fine particles to polyolefin and peeling the interface between the polyolefin serving as a matrix and the fine particles (JP-A-1-293102).

However, in the methods described in JP-B-56-52123 and JP-A-57-42919, the film material is limited to the polyolefin having a relatively high crystallization rate among the crystalline polymers. In addition, Japanese Patent Laid-Open No. 1-
The method described in Japanese Patent No. 293102 also discloses only a polyolefin having a relatively low cohesive force as a film material.

On the other hand, in recent years, polyketone-based polymers have been attracting attention and studied from the viewpoints of heat resistance, acid resistance, alkali resistance and the like as membrane materials. For example, Japanese Patent Laid-Open No. 2-1362
Japanese Patent Publication No. 29 discloses a polyetheretherketone (hereinafter abbreviated as PEEK) porous film by a wet method.

This membrane is prepared by dissolving PEEK polymer in a non-sulphonating acid solvent and then in a coagulation bath which is non-solvent for PEEK polymer but miscible with non-sulphonating acid solvent. It is manufactured by solidifying and has an asymmetric structure in which the surface of the film is a skin layer and the inside of the film is a finger-like cavity.

Further, Japanese Unexamined Patent Publication No. 4-293533 discloses a PEEK porous flat membrane by an extraction method. This film is produced by mixing PEEK polymer and a low melting point crystallizable polymer, melt-forming into a film, and then extracting the low melting point crystallizable polymer to obtain a symmetrical or asymmetric structure.

However, generally, in the wet method and the extraction method, the shape of the pores is circular, and as for the polyketone membrane, a porous membrane having slit-shaped fine pores has not been disclosed so far. Further, regarding a polymer having a relatively low crystallization rate such as polyketone, a method for producing a porous film by a melt-shaped drawing method has not been disclosed so far.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyketone porous membrane having slit-shaped fine pores which is excellent in heat resistance, pressure resistance and chemical resistance.

[0011]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors obtained a film of the above object by mixing a specific amount of fine particles having a specific particle size with a polyketone polymer. I found it.

That is, the gist of the present invention is polyketone polymer 4
A porous film comprising 0 to 95% by weight and 60 to 5% by weight of fine particles having an average particle size of 0.02 to 10 μm,
The polyketone porous membrane has fine pores penetrating in the thickness direction of the porous membrane, and the fine pores are slit-like fine pores having an average width of 0.01 to 10 μm, and a method for producing the same.

The present invention will be described below. The polyketone polymer of the present invention is a polymer composed of a monomer unit having a —CO— group in its molecule. For example, the following formulas (I) to (VI) (wherein the benzene ring is an alkyl group) , Which may be substituted with a halogen, a nitro group, a sulfonyl group, a carboxyl group or the like).

[0014]

[Chemical 1]

The fine particles in the present invention are not particularly limited as long as they have an average particle diameter of 0.02 to 10 μm, and either inorganic fine particles or organic fine particles can be used. Examples of the inorganic fine particles include calcium carbonate, calcium oxide, titanium oxide, silica, magnesium oxide, aluminum oxide, aluminum sulfate, barium sulfate, talc, clay, and the like, and organic fine particles include crosslinked silicone resin, crosslinked polystyrene resin, and crosslinked. PMMK resin etc. are mentioned.

The average particle size of the fine particles is 0.02 to 10 μm.
It is necessary to be. The average particle size of the fine particles is 0.0
When it is smaller than 2 μm, it does not become porous even if it is stretched. On the other hand, when the average particle size of the fine particles exceeds 10 μm, the slit width of the fine pores generated by stretching becomes too large, resulting in poor mechanical strength and unusable as a film.

Polyketone polymer and average particle size 0.02
The mixing ratio with the fine particles having a particle size of 10 μm must be 40 to 95% by weight of the polyketone polymer and 60 to 5% by weight of the fine particles. If the mixing ratio of the fine particles exceeds 60% by weight, the stretching becomes difficult, and conversely, if it is less than 5% by weight, the formation of the through holes becomes difficult.

The porosity of the polyketone porous membrane of the present invention is preferably 10 to 95% in terms of filtration performance.

The feature of the present invention resides in a polyketone porous membrane in which a specific amount of fine particles having a specific particle size are mixed, and by mixing the fine particles, a slit-like fine through hole having a relatively large average width of 0.01 μm or more. A polyketone porous membrane having the same can be obtained. Further, by controlling the particle diameter of the fine particles, the width of the slit-shaped fine holes can be controlled easily and accurately.

Since the membrane of the present invention is integrated with fine particles, it is more excellent in heat resistance and pressure resistance than a porous membrane containing only polyketone. The polyketone porous membrane of the present invention may have a flat membrane shape or a hollow fiber shape.

Next, an example of the method for producing the polyketone porous membrane of the present invention will be described. When the polyketone porous membrane of the present invention is a hollow fiber, it can be produced by mixing a specific amount of a polyketone polymer and fine particles having a specific particle size, melt-forming into a hollow fiber shape, and stretching.

The mixing method is not particularly limited, and known mixing methods can be used. For example, the above components may be added to and mixed with a mixer such as a Henschel mixer, or may be melt-kneaded with a uniaxial or biaxial screw extruder, and the extruded product may be cut into pellets before use.

Next, the above mixture is melt-shaped into hollow fibers. As the hollow fiber manufacturing nozzle used in the melt shaping, a known double-cylindrical type, bridge type, or the like can be used.

The melt shaping temperature is preferably 300 to 450 ° C. If the temperature is less than 300 ° C, spinning is difficult, while if it exceeds 450 ° C, the polyketone polymer is decomposed.

The mixture discharged from the nozzle at a temperature in this range is preferably wound in a draft ratio of 1 to 200, more preferably 1 to 100. If the draft ratio is less than 1, it is difficult to stably wind the fiber. On the contrary, if the draft ratio exceeds 200, the orientation of the undrawn yarn proceeds, and the subsequent drawing process becomes difficult.

Next, the obtained hollow fiber is drawn. The hollow fiber has a porous structure by being drawn. That is, voids and crazes are generated around the fine particles by stretching, and these expand with stretching to form slit-shaped fine holes, and slit-shaped fine holes having a width corresponding to the particle diameter are formed. Therefore, by controlling the particle size of the fine particles, the slit width of the fine holes can be controlled.

The stretching temperature is preferably equal to or higher than the glass transition point (Tg) of the polyketone polymer, more preferably in the temperature range of 0 to 150 ° C. higher than Tg. If it is less than Tg, the fluidity of the polyketone polymer is low, so that stretching becomes difficult.
However, if the stretched amount is up to 50%, it is possible to stretch at a temperature lower than Tg, and then a method of stretching at Tg or higher is also adopted.

The deformation rate during stretching is preferably 1% / min or more. When the deformation rate is less than 1% / min, the drawing is non-uniform and yarn breakage easily occurs during the drawing. As a stretching method, for example, the stretching can be performed continuously between rollers, but a more uniform stretching can be performed by performing the stretching in two or more stages.

The stretching amount is preferably 100 to 900% (that is, a stretching ratio of 2.0 to 10.0 times), more preferably 2
It is from 00 to 800%. When the stretching amount is less than 100%, the fine holes generated around the fine particles are independent,
It does not become a through hole.

By stretching by 100% or more, the generated slit-shaped fine holes are connected to each other to form a through hole. On the other hand, if the stretched amount exceeds 900%, yarn breakage tends to occur during stretching.

If necessary, the obtained porous hollow fiber membrane can be heat-set at a Tg or higher of the polymer.

By the above method, the average width is 0.01 to 10 μm.
A polyketone porous hollow fiber membrane in which the slit-like fine pores of (3) penetrate in the thickness direction is obtained. The porous hollow fiber membrane thus obtained preferably has an outer diameter of 2 mm or less, more preferably 20 to 1000 μm.

The wall thickness is preferably 500 μm or less, more preferably 5 to 400 μm. If the outer diameter of the porous hollow fiber membrane exceeds 2 mm, it tends to be difficult to maintain the hollow shape, and flattening tends to occur particularly when external pressure is applied. When the outer diameter is smaller than 20 μm, yarn breakage easily occurs during spinning.

When the polyketone porous membrane of the present invention is a flat membrane, the polyketone polymer and the fine particle mixture having a specific particle size are shaped into a film by a melt extrusion method and then stretched. it can.

The film may be stretched uniaxially,
Biaxial stretching may be performed to the extent that mechanical strength is not reduced.
The thickness of the film is 5 to 500 μm, and the more preferable range is 5 to 400 μm.

As described above, the feature of the present invention resides in the polyketone porous membrane in which a specific amount of fine particles having a specific particle diameter are mixed, and the average width of the polyketone is relatively large by 0.01 μm or more. It is possible to obtain a polyketone porous film having slit-shaped fine through holes, and moreover, by controlling the particle size of the fine particles, the width of the slit-shaped fine holes can be easily and accurately controlled.

[0037]

The present invention will be described in detail with reference to the following examples. Example 1 60 parts by weight of polyether ether ketone (Victrex PEEK "150P" manufactured by ICI Japan) and 40 parts by weight of crosslinked silicone fine particles having an average particle size of 0.8 μm ("Tospearl 108" manufactured by Toshiba Silicone Co., Ltd.) were mixed, Kneading was performed at 380 ° C. with a twin-screw extruder to obtain pellets.

The pellets thus obtained were subjected to a spinning temperature of 400 ° C. and a linear discharge speed of 1 by using a double cylinder type hollow fiber for producing slurries.
Spinning was performed at 0 cm / min, a winding speed of 4 m / min, and a draft ratio of 40. Then, the unstretched hollow fiber obtained was used as 1
At a deformation rate of 45% and 10% / min, the stretching amount is 300.
The film was hot-stretched so that the content became%.

The obtained porous hollow fiber membrane has an outer diameter of 800 μm.
m and an inner diameter of 500 μm. Further, the outer surface, inner surface and cross section of the hollow fiber membrane were observed with a scanning electron microscope (hereinafter abbreviated as SEM). As a result, an average width of 0.6 μm and an average length of 4
It was confirmed that slit-shaped fine pores of μm were opened and penetrated in the thickness direction. The porosity of this hollow fiber membrane is 72
%Met.

Example 2 70 parts by weight of polyetherketone (Victrex PEK "220P" manufactured by ICI Japan) and an average particle size of 0.8 μ
30 parts by weight of crosslinked silicone fine particles of m (“TOSPEARL 108” manufactured by Toshiba Silicone Co., Ltd.) were mixed and kneaded at 400 ° C. by a twin-screw extruder to obtain pellets.

The pellets thus obtained were subjected to a spinning temperature of 420 ° C. and a linear discharge speed of 1 using a nozzle for producing a double cylindrical hollow fiber.
Spinning was performed at 0 cm / min, a winding speed of 1 m / min, and a draft ratio of 10. Then, the unstretched hollow fiber obtained was used as 1
The stretching amount is 50 at a deformation rate of 65% at 100% / min.
It was hot stretched to 0%.

The obtained porous hollow fiber membrane has an outer diameter of 560 μm.
m and an inner diameter of 480 μm. Moreover, as a result of observing the inner surface, the outer surface and the cross section of the hollow fiber membrane with an SEM, it was confirmed that slit-shaped micropores having an average width of 0.5 μm and an average length of 5 μm were opened and penetrated in the thickness direction. It was The porosity was 80%.

Example 3 85 parts by weight of polyether ether ketone (Victrex PEEK "380P" manufactured by ICI Japan) and 15 parts by weight of crosslinked silicone fine particles having an average particle size of 0.3 μm ("Tospearl 103" manufactured by Toshiba Silicone Co., Ltd.) The mixture was mixed and kneaded with a twin-screw extruder at 380 ° C. to obtain pellets.

The pellets thus obtained were subjected to a spinning temperature of 400 ° C. and a discharge linear velocity of 1 using a double cylinder type hollow fiber producing nozzle.
Spinning was performed at 0 cm / min, a winding speed of 0.3 m / min, and a draft ratio of 3. Next, the obtained unstretched hollow fiber was heat-stretched at 145 ° C. at a deformation rate of 1000% / min so that the stretched amount was 700%, and then heat-set at 230 ° C. for 1 minute. .

The obtained porous hollow fiber membrane has an outer diameter of 400 μm.
m and an inner diameter of 270 μm. In addition, as a result of observing the inner surface, the outer surface and the cross section of the hollow fiber membrane with an SEM, it was confirmed that slit-shaped micropores having an average width of 0.2 μm and an average length of 10 μm were opened and penetrated in the thickness direction. It was The porosity was 84%.

Example 4 70 parts by weight of polyether ether ketone (Victrex PEEK "380P" manufactured by ICI Japan) and 30 parts by weight of surface-treated calcium carbonate fine particles ("PO filler" manufactured by Shiraishi Calcium Co., Ltd.) having an average particle size of 1.0 μm. Mix the parts,
The mixture was kneaded at 400 ° C. with a twin-screw extruder to obtain pellets.

The obtained pellets were subjected to a spinning temperature of 400 ° C. and a discharge linear velocity of 1 using a double cylinder type hollow fiber producing nozzle.
Spinning was performed at 0 cm / min, a winding speed of 1 m / min, and a draft ratio of 10. Then, the unstretched hollow fiber obtained was used as 1
At 45 ° C and a deformation rate of 100% / min, the total stretching amount is 5
The film was hot-stretched in five stages so that it would be 00%.

The obtained porous hollow fiber membrane has an outer diameter of 570 μm.
m and an inner diameter of 500 μm. Moreover, as a result of observing the inner surface, the outer surface and the cross section of the hollow fiber membrane with an SEM, it was confirmed that slit-shaped fine holes having an average width of 0.8 μm and an average length of 5 μm were opened and penetrated in the thickness direction. It was

Example 5 70 parts by weight of polyether ether ketone (Victrex PEEK "450P" manufactured by ICI Japan) and 30 parts by weight of crosslinked silicone fine particles having an average particle size of 2.0 μm ("Tospearl 120" manufactured by Toshiba Silicone Co., Ltd.) The mixture was mixed and kneaded with a twin-screw extruder at 400 ° C. to obtain pellets.

The obtained pellets were extruded using a film die at 400 ° C. to obtain a film. Then film 1
At a deformation rate of 45 ° C and 3000% / min, the stretching amount is 3
The film was uniaxially heat-stretched so as to be 00% to obtain a porous flat film.

The thickness of the obtained film was 50 μm. SEM observation shows average width of 2μm and average length of 10μ
m slit-shaped fine holes were open.

[0052]

EFFECT OF THE INVENTION The polyketone porous membrane of the present invention has slit-like fine pores having an average width of 0.01 to 10 μm penetrating in the thickness direction, and has the characteristics not found in conventional products, and has heat resistance and pressure resistance. Therefore, it has wide suitability for medical applications requiring steam sterilization, food applications, high temperature filtration separation applications, and the like.

Claims (4)

[Claims] 1. A porous membrane comprising 40 to 95% by weight of a polyketone polymer and 60 to 5% by weight of fine particles having an average particle diameter of 0.02 to 10 μm, wherein the fine pores are present in the thickness direction of the porous membrane. Penetrate, and the fine holes have an average width of 0.01 to
A polyketone porous membrane having slit-like fine pores of 10 μm. 2. The porous membrane according to claim 1, wherein the porous membrane is a hollow fiber membrane. 3. The porous membrane according to claim 1, wherein the porous membrane is a film. 4. A mixture of 40 to 95% by weight of a polyketone polymer and 60 to 5% by weight of fine particles having an average particle size of 0.02 to 10 μm, and then melt-molded into a predetermined shape, and then this shaped product. The method for producing a porous membrane according to claim 1, wherein the porous membrane is stretched.