JPH0369673A - Heat-resistant hydrophilic porous polyolefin hollow fiber - Google Patents

Abstract

PURPOSE:To provide the subject hollow fiber having excellent heat resistance and hydrophilicity by adhering a specific polymer coating film to the surface of a porous polyethylene hollow fiber wherein fine pores formed among many fibrils are communicated through the inner and outer walls of the hollow fiber. CONSTITUTION:A porous polyolefin hollow fiber wherein fine pores formed among many fibrils arranged in the longitudinal direction of the polyolefin hollow fiber are communicated through the inner and outer walls of the hollow fiber are immersed in a treating solution containing 95-5wt.% of a compound of the formula (n is 10-100; R' is H or CH3) and 5-95wt.% of a monomer having at least two double bonds copolymerizable with the compound of the formula to adhere the coating film of the polymer of the monomers to the surface of the hollow fiber, thereby providing a porous polyolefin hollow fiber having excellent heat resistance and hydrophilicity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a porous polyolefin hollow fiber having excellent heat resistance and hydrophilicity.

[Conventional technology]

Conventionally, as a pure water production device used in various fields such as medical, pharmaceutical, food industry, precision industry, and physical and chemical experiments, we have developed a pure water production device that does not contain colloidal substances or bacteria, and also A wide variety of devices have been proposed, including devices for producing pure water that do not contain pyrogens. For example, sterile water production equipment used in the medical field includes equipment using distillation methods, boiling sterilizers, and ultraviolet sterilizers, but the energy and equipment costs are high, and sterilization is insufficient. ,
Additionally, some devices have drawbacks, such as being able to remove colloidal substances and bacteria, but not pyrogenic substances (pyrogienes).

Given this current situation, in order to solve the drawbacks of conventional devices, we developed a fiber IJ in which micropores with a pore diameter of 0.01 to 1 μm that can remove exothermic substances communicate from the inner wall surface of the hollow fiber to the outer wall surface.
A porous polyolefin hollow fiber membrane having a diameter of /7 has been proposed in JP-A-57-42919.

[Problem to be solved by the invention]

As mentioned above, membrane modules using porous polyolefin hollow fibers have various advantages, but because they are hydrophobic, they cannot be fully hydrophilized unless treated with a hydrophilic agent such as Aμcol. F water performance is not obtained, and after water has been filtered for a long time, the water is removed to clean the module, and when the surface of the porous polyolefin hollow fibers is dried by contacting with air, the P water property decreases significantly. There is a problem with doing so. Furthermore, when hot water is filtered, the threads shrink significantly and become crushed due to softening, resulting in a decrease in reactor water properties.

An object of the present invention is to provide a porous polyolefin hollow fiber having excellent heat resistance and hydrophilicity.

[Means to solve the problem]

The gist of the present invention is to provide a porous polyolefin hollow fiber in which micropores formed between a large number of fibrils arranged substantially in the longitudinal direction of the hollow fiber communicate between the inner wall surface and the outer wall surface of the hollow fiber. 95 to 95 on the surface of the fip VtV.
5% by weight of the formula (A) (where n is 10 to 100, R is an alkyl group having 12 or more carbon atoms, an acryloyl group or a methacryloyl μ group, and s R' is hydrogen or a methacryloyl μ group).

A mixture of at least two or more compounds containing the compound represented by 5 to 95% by weight of a monomer having at least two or more double bonds copolymerizable with the compound is fixed by thermal polymerization. It is a heat-resistant, hydrophilic porous polyolefin hollow fiber.

The porous polyolefin hollow fiber used in the present invention, in which micropores are connected to the inner and outer wall surfaces of the hollow fiber, was disclosed in Japanese Patent Application Laid-open No. 5
It can be obtained by the manufacturing method disclosed in Japanese Patent No. 7-42919.

If the amount of the compound represented by formula (A) exceeds 95% by weight, the film formation properties will be poor, and the physical durability will be low.

Moreover, if it is less than 5% by weight, the hydrophilic power will be insufficient and the water flux will be low.

Also, in the compound of formula (A), polyethylene glycol
The degree of polymerization n of the chains ranges from 10 to 100. If n is less than 10, the hydrophilic performance will not be sufficient, and if n is more than 100, the viscosity will increase, and the micropores in the porous layer will be blocked, resulting in a decrease in flux, which is not preferable. Further, when R is an alkyl group, the number of carbon atoms is preferably 12 or more in order to obtain affinity with polyolefin. Although the above compound exhibits good hydrophilic properties even when used alone, the second command is added in an amount of 95 to 5% by weight to improve film forming properties.

As the second component, a monomer having at least two or more double bonds copolymerizable with the first component represented by the above formula (A) is used, such as dimethacrylic acid ethidine glycol p1 methacrylic acid Allyl, 2-methacryloxyethylmaleic acid, dimethacrylic acid-1,3-butylene glyco-
μ, trimethylolpropane trimethacrylate, pentaerythritome tetofmethacrylate μ, and the like. By adding 5 to 95% by weight of this second component, the film forming ability is significantly improved, and a uniform polymer film can be obtained without impairing the hydrophilic performance.

As a method for polymerizing and fixing the above compounds on the fibril surface of porous polyolefin hollow fibers, the above compounds are dissolved in a solution of at least two or more of the above compounds in a solvent that easily wets polyolefins such as methanol. After soaking the hollow fibers of a polyolefin, the solvent is removed by air drying or the like to carry out polymerization. As the polymerization method, thermal polymerization is preferred in order not to impair the high elongation at break, which is a characteristic of the polyolefin hollow fibers serving as the base material.

As the polymerization initiator, a type A peroxide, an azo compound, or a redox initiator known as a radical polymerization initiator can be used. Examples include 2,2'-azobisinbutyronitrile, 2,21-azobiscycloprobilprobionitrile, 2,2'-azobis-2,
4-dimethymuvaleronitrile, 2,2'-azobis-2
, azo compounds such as S3-trimethylbutyronitrile,
Acetyl peroxide, propionyl peroxide, butyryl peroxide, isobutyryl peroxide, succini μ peroxide, pencil peroxide, bency μ isobutyl peroxide, β-allyloxypropionyl peroxide, hexanoyl peroxide , peroxides such as 5-bromobenzoyl peroxide, and persulfates such as potassium persulfate and ammonium persulfate.

Further, the polymerization initiator may be about 001 to 100 parts by weight based on 100 parts by weight of the monomers (LO1 to 3).
It is preferable that the amount is about 0 parts by weight.

The polymerization temperature should be higher than the decomposition temperature of the polymerization catalyst, and preferably lower than the temperature that does not change the membrane structure of the porous polyolefin membrane and damage the membrane substrate!
Usually, a temperature of about 30 to 100°C can be employed.

The heating time depends on the type of polymerization catalyst and the heating temperature, but is usually about 1 minute to 5 hours, preferably 15 minutes to 5 hours.
It takes about an hour.

By carrying out the above treatment, it becomes possible to impart good hydrophilic properties to the fibril N surface of the porous polyolefin hollow fiber. In addition, the fixed polymer coating is a highly crosslinked and heat resistant coating, and a crosslinked structure is also introduced inside the hollow fibers, so the fibers will not collapse due to softening when hot water is filtered. It becomes possible to suppress thermal contraction.

〔Example〕

The present invention will be explained in detail below with reference to Examples.

Example 1 A porous polyethylene hollow fiber (EHF manufactured by Mitsubishi Rayon Co., Ltd.) with a breaking elongation of 60% was mixed with an acrylic acid alkoxypolyethylene glyco-p compound (n = 3 in formula A).
0, only carbon number 12) 5 parts by weight, cyacrylic acid tetophethyl resin lyco-/L' 5 parts by weight and Pencil μ peroxide 05 parts by weight were dissolved in 1v 90 parts by weight of methanol at 20 °C. After immersing for 30 seconds, the methanol-μ was removed by air drying for 10 minutes.

Next, transfer the hollow fiber to a sealed container and replace the air with nitrogen.7
The temperature was raised to 0°C and maintained at that temperature for 2 hours to carry out a polymerization reaction, thereby fixing a polymer film to the surface of the laminated fibrillar structure of porous polyethylene hollow fibers.

The elongation at break of the heat-resistant hydrophilic porous polyethylene hollow fiber membrane produced in this manner was 50%.

Next, the above heat-resistant and hydrophilized porous polyethylene hollow fiber 10
Bundle the fibers into a U-shape, harden the opening of the hollow fibers with resin,
A membrane module with a resin-embedded part length of 45I and a hollow fiber effective length of 10α was manufactured.

As a reference example, a normal membrane module was manufactured in the same manner as above using the porous polyethylene hollow fibers that had not been subjected to the heat-resistant hydrophilic treatment.

As a result of measuring the water permeability pressure and water permeability of the above heat-resistant hydrophilized porous polyethylene hollow fiber module, (L O5k
Water filtration is started at a low pressure of 5 g/ls”, and the water pressure is 1
The water permeability at 9 #151” is 13 (n15I!l1m1
It was n.

On the other hand, a module using porous polyethylene hollow fibers that was not heat-resistant and hydrophilized was prepared as a reference example.
The water permeability pressure was extremely high, and no water was filtered at all even when a pressure of 3 kll/ls was applied.Furthermore, the water permeability pressure of the above module using heat-resistant, hydrophilized porous polyethylene hollow fibers was 1 kl! After filtering hot water at 80°C for 1 hour, the hot water was extracted and dried at 60°C in a vacuum dryer for 2 hours.
After drying for 4 hours, the water permeation pressure and water permeation amount were measured again, and no deterioration in performance was observed even though the hot water was filtered and dried.

Comparative Example 1 Porous polyethylene hollow fibers were prepared in the same manner as in Example 1 using an acrylic acid alkoxypolyethylene glyco compound (A
In the formula, n = 30, carbon number of R is 12) 5 parts by weight and 15 parts by weight of diacrylic acid tetophethidine grease were dissolved in 90 parts by weight of methano-IL/20°C. It was immersed for 30 seconds in a solution at 20 ° C. Thereafter, methanol was removed by air drying for 10 minutes.

Subsequently, using an electron beam irradiation device (Nissin Hypotage, Curetron EBC-2QQ-20-15),
An electron beam was irradiated at a dose of Mrad to fix the polymer film to the surface of the laminated structure of porous polyethylene hollow fibers.

The elongation at break of the hollow fiber thus produced was 10%.

Example 2 The same porous polyethylene hollow fiber as in Example 1 was made of polyethylene glycol diacrylate (n = 30 in formula A).
, R is an acryloyl μ group), 5 parts by weight of trimethylo μpropane trimethacrylate, and 0.1 part by weight of 2.2'-azobisinbutyrodi) IJ/L' were dissolved in 90 parts by weight of acetone. The acetone was removed by immersing it in a solution at 20°C for 10 seconds and then air drying it for 10 minutes. Subsequently, polymerization was carried out in nitrogen at 90° C. for 5 minutes to obtain a heat-resistant, hydrophilized polyethylene porous membrane.

The elongation at break of this Iw hot water hydrated hollow fiber was 55%.

Next, a membrane module μ similar to that in Example 1 was manufactured using the heat-resistant hydrophilized polyethylene hollow fibers, and the water permeation pressure and water permeation amount were measured, and water permeation started at a low pressure of 11 kg/z''. , water permeability at water pressure 1 Yu/α2 is 12 CC
/cm”・min.

Further, no deterioration in performance was observed even after hot water filtration and drying at 80°C.

Example 3 The porous polyethylene hollow fiber E) (F is polyethylene glycol dimethacrylate (n = 25.
(R is a methacryloyl μ group) 10: The yarn is less likely to collapse or shrink.

The ethanol was removed by immersing it in a solution of 85 parts by weight at 20° C. for 5 seconds and air drying for 5 minutes. Subsequently, polymerization was carried out in nitrogen at 80° C. for 5 minutes to obtain a heat-resistant hydrophilized polyethylene porous membrane. The elongation at break of this heat-resistant, hydrophilized hollow fiber was 55%.

Next, a module similar to that in Example 1 was fabricated using the heat-resistant hydrophilized polyethylene hollow fibers, and the water permeation pressure and water permeation amount were measured. Water permeated at a low pressure of 1 kg/am", and the water pressure was 1.- / m” water permeability is IS
It was a win.

Further, no deterioration in performance was observed even after hot water filtration and drying at 80°C.

〔Effect of the invention〕

Claims (1)

[Claims] A porous polyolefin hollow fiber in which micropores formed between a large number of fibrils arranged substantially in the longitudinal direction of the hollow fiber communicate between the inner wall surface and the outer wall surface of the hollow fiber. A monomer having at least two or more double bonds copolymerizable with 95 to 5% by weight of the compound represented by formula (A) and 5 to 95% by weight of the compound of formula (A) on the surface of fipril. 1. A heat-resistant, hydrophilic porous polyolefin hollow fiber comprising a mixture of at least two or more kinds of compounds, including a polymer and a polymer, which are thermally polymerized and fixed. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(A) (However, n is 10 to 100, R is an alkyl group having 12 or more carbon atoms, an acryloyl group, or a methacryloyl group, and R' is hydrogen or methyl group)