JPH0788017B2 - Manufacturing method of porous material - Google Patents

Description

The present invention relates to a wide range of methods for producing a porous material, more specifically, as a printing material or a clothing material, or as a membrane filter, an ion exchange membrane, or a carrier for a bioreactor. The present invention relates to a novel method for producing a porous material of an ethylenically unsaturated compound having use.

2. Description of the Related Art Conventionally, the following method has been known as a method for producing a porous material.

First, as a method for producing a porous film, (1) a method in which a polymer substance such as cellulose acetate is dissolved in a solvent, a non-solvent is added to the solution, this is applied on a substrate, and then the solvent is removed by evaporation. (See, for example, U.S. Pat. No. 1421341), (2) A method of improving porosity by adding a metal salt in the same manner as (1) (JP-A-48-3216).
(See No. 7), (3) A method in which two types of polymers are dissolved in the same solvent, coated on a substrate, dried to form a film, and one of the polymers is extracted with a solvent (Japanese Patent Publication No. Sho 53-9632). , Shokoku Sho 61
-39978)) etc.

In addition, as a method for coating a porous material on a substrate, (4) a so-called wet film formation method in which a polymer solution such as polyurethane or polyamide is applied to the substrate and immersed in water to solidify the polymer, (5) There is a method in which air bubbles are mixed in an aqueous dispersion of a polymer, which is applied to a base material and dried by heating to form a film.

Furthermore, as a method of utilizing active energy rays,
(6) A method of mixing a monomer with a buffer solution, low-temperature polymerization by radiation and freezing water to obtain a porous polymer (Chemicals and Industry, 38 , No, p. 768 (1985), (7) 1 One or more polar vinyl monomers, or one or more polar vinyl monomers and one or more donor monomers and a metal halide are dissolved or dispersed in a solvent that does not dissolve the polymer of the monomers, and the solvent or dispersion medium is at least a part. There is a method in which the monomer is cooled to a temperature at which it is solidified, the above-mentioned monomer is polymerized by irradiation with radiation, and then unreacted monomer and the like is removed by heating (see Japanese Patent Publication No. 37666/51).

Problems to be Solved by the Invention However, the above-mentioned conventional methods have various drawbacks.

That is, in any of the methods, the usable polymers are limited, the controllable range of the structure of the pores is narrow, and there is no one that can be used as both a porous film and a porous coating. Is limited to a narrow range.

Further, for example, in the methods (1) and (2), it is difficult to obtain a homogeneous porous structure even if the manufacturing conditions are strictly controlled, and it takes a long time to manufacture. In the method (3), the structure of the pores becomes non-uniform, or the particles associate with each other over time to change the structure of the pores, resulting in gelation in some cases. In the method (4), the polymer that can be used is limited, macropores are easily generated under some conditions, and it is difficult to obtain a structure having a uniform pore diameter. Further, the method (5) cannot obtain a porous body having a pore size of several microns or less, and the pore size is limited. Further, the methods (6) and (7) using the active energy rays are advanced methods, but are inferior in practicality in that they use a reaction at a low temperature.

Means for Solving the Problems In view of such circumstances, the present inventors have obtained a uniform and wide-range porous structure without limiting the usable raw materials to a narrow range in order to eliminate the drawbacks of the above method. The present invention has been completed as a result of extensive research on a method for producing a porous material that does not require special conditions such as low temperature conditions.

That is, the present invention, the composition comprising an ethylenically unsaturated compound and an alcohol is coated or cast on a substrate, irradiated with an active energy ray to cure the compound, remove the alcohol, Next, if desired, the method comprises the step of peeling the cured product, and the amount of alcohol in the composition dissolves the ethylenically unsaturated compound before curing, but the cured product produced during curing phase-separates into a cloudy state. The present invention provides a method for producing a porous material, which is characterized in that

The raw material ethylenically unsaturated compound that can be used in the present invention may be any one that is curable with respect to active energy rays, and can be used alone or in combination. Such acrylate-based, urethane acrylate-based, epoxy acrylate-based and ester acrylate-based monomers or oligomers (prepolymers) may be mentioned. That is, examples of the monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydroxyfurfuryl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, tetrahydrofurfuryloxyhexanolide acrylate and 1 Monofunctional acrylate-based monomers such as 1,3-dioxolane acrylate, hexanediol diacrylate, neopentyl glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, neopentyl glycol adipate diacrylate and hydroxypiperic acid neo Diethyl of ε-caprolactone adduct of pentyl glycol Bifunctional acrylate monomers such as acrylates and polyfunctional acrylates such as trimethylolpropane triacrylate, dipentaerythritol triacrylate propionate, pentaerythritol tetraacrylate propionate, ditrimethylolpropane tetraacrylate and dipentaerythritol hexaacrylate Acrylic monomers such as monomers are included. Examples of the oligomer (prepolymer) include the following typical structural formulas: A urethane acrylate system having a soft segment and a hard segment bonded with a diisocyanate, having a structural formula: An epoxy acrylate system having, and for example the structural formula: Examples thereof include ester acrylate-based oligomers (prepolymers).

On the other hand, examples of alcohols that can be used in the present invention include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, n-amyl alcohol, isoamyl alcohol, n-hexanol, methyl-tert-butylcarbinol, n-heptyl alcohol, n-octyl alcohol, n-nonyl alcohol, monohydric alcohols such as n-dodecyl alcohol, dihydric alcohols such as ethylene glycol and propylene glycol, and glycerin. Trihydric alcohols such as pentaerythritol and diethylene glycol, triethylene glycol, polyethylene glycol (molecular weight 200-100
00) and condensation type alcohols such as polypropylene glycol. Generally, butyl alcohol, isopropyl alcohol, glycerin, ethylene glycol, depending on the combination with an ethylenically unsaturated compound,
It is preferable to use diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol or the like. These alcohols can be used alone or in combination.

Since the generation mechanism of the porous structure in the production method of the present invention can be presumed as follows, it is important to select the type and amount of alcohol used. The alcohol dissolves the monomer or oligomer of the ethylenically unsaturated compound before the irradiation of the active energy ray, but the polymer produced by the irradiation is phase-separated, and complete curing occurs in the phase-separated state, resulting in a porous structure. It is considered that the cured film of
The amount of the alcohol can be appropriately and easily selected by testing a combination of the individual ethylenically unsaturated compound and the alcohol actually used by using a small amount of sample. Generally, 20 to 150 parts by weight of alcohol is used with respect to 100 parts by weight of the ethylenically unsaturated compound.

Thus, in order to carry out the present invention, first, a composition prepared by mixing the monomer or oligomer of the ethylenically unsaturated compound as described above and the selected type and amount of alcohol is prepared. Then, the composition is applied or cast onto a substrate, depending on the intended use form of the final porous material as described below. The substrate may be a known material suitable for coating as described below, for example, knitted fabric, nonwoven fabric, paper, various films, or a casting mold.
The thickness of the final porous material obtained by the production method of the present invention is generally in the range of 0.1 to 2000 μm, and the coating amount or casting amount can be appropriately selected according to the thickness of the final object.

If desired, the composition before irradiation may contain a filler or coloring agent such as calcium carbonate to give additional performance to the final porous material, or a solvent such as MEK or toluene may be added in a small amount to adjust the viscosity of the composition. It can be performed.

After coating or casting, a predetermined active energy ray is irradiated. Irradiation can be performed in multiple times. Examples of active energy rays used include electron rays and ultraviolet rays. In the case of electron beam irradiation, irradiation with an accelerating voltage of 100 to 1000 KV and an absorbed dose of 0.1 to 20 Mrad is appropriate, and irradiation is performed while maintaining the oxygen concentration in the atmosphere at 1000 ppm or less from the viewpoint of improving the performance of the obtained porous material. Is preferred. In the case of ultraviolet irradiation, generally, near-ultraviolet light having a wavelength of 2000 to 4500Å is used, and an appropriate amount of a photoinitiator such as benzophenone or benzoylphenyl ether is added.

Polymerization is initiated by irradiation with an active energy ray, and as described above, a polymer is produced to cause phase separation and become cloudy. It is completely cured in the state where this phase separation has occurred. A porous structure forms upon curing. The time required for irradiation varies depending on the active energy ray, but is generally in the range of 0.1 second to several tens of seconds.

After irradiation, alcohol is removed by heating, washing with water, etc., and if necessary, drying is performed to obtain a porous material.

The porous material obtained by the production method of the present invention comprising the above steps generally has a pore size of 0.1 to 50 μm and can be used in various forms. First, a porous layer can be formed on a base material and used as an integrated body. This is a so-called coating type application, and can be applied to, for example, a printing material by imparting printability to the surface of a substrate, or a clothing material by imparting both moisture permeability and water resistance. Further, a porous layer is formed on a releasable substrate, which can be peeled off and used alone as a functional film or sheet. For example, it can be applied as a material for microfiltration as a membrane filter, or can be applied to a selective separation function membrane such as an ion exchange membrane or a reverse osmosis membrane. Furthermore, since a porous structure is instantly formed, it is suitable for embedding oxygen and the like and curing, and can be applied to a bioreactor.

EFFECTS OF THE INVENTION The production method of the present invention has a wide range of applicable raw materials, and has an advantage that various porous materials can be obtained as a single film, sheet, or as an integral body with a substrate as described above. In addition to the above, for example, hydrophilic ones and hydrophobic ones can be manufactured separately.

Further, since the porous structure is instantly formed by the irradiation of the active energy ray, the porous structure can be stably obtained and the productivity is extremely good.

Furthermore, there is also an advantage that the structure of the pores can be controlled by appropriately selecting the conditions. Generally, as the alcohol becomes chemically more hydrophilic to the ethylenically unsaturated compound (ie, eg, ethylene glycol <triethylene glycol <polyethylene glycol (molecular weight 200) <polyethylene glycol (molecular weight 40
As shown in 0), the particles become finer as they become more hydrophobic, and a small particle (diameter of 0.1 to 0.5 μ) has a sintered structure.
An example of this is shown in the substitute photograph of FIG. On the contrary, the pores become larger when the affinities of the two are separated, and the mesh-like pores (FIG. 2) due to the chain-like bonds between the particles are formed, and further circular pores (FIG. 3) are formed.

Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 A 0.1 mm thick coating liquid composition having the following composition was applied to a polyethylene terephthalate film having a thickness of 0.1 mm which had been subjected to a release treatment.
Applied to the thickness of.

Trimethylolpropane triacrylate (trifunctional acrylic monomer) 39 parts by weight Polyfunctional acrylic oligomer (Toacron M-8060, manufactured by Toagosei Co., Ltd.) 17 parts by weight Polyethylene glycol (molecular weight 200) 44 parts by weight 120W UV irradiation Irradiation was carried out 3 times at a speed of 10 m / min using an apparatus to harden it to a cloudy state, followed by washing in running water at 40 ° C. for 3 hours and drying at 50 ° C. to separate the multi-hard layer from the base film. The obtained porous film has a thickness of 0.11 mm, has a small-grain sintered type porous structure, and has a pore size of 0.1 to 0.3 μ and a porosity of 40%.
Met.

Example 2 A porous film was obtained by the same method as in Example 1 except that a coating liquid composition having the following composition was used.

Trimethylolpropane triacrylate 9 parts by weight Urethane acrylate oligomer (Toacron M-11
00, manufactured by Toagosei Co., Ltd. 36 parts by weight Acrylic oligomer (Toacron M-152, manufactured by Toagosei Co., Ltd.) 15 parts by weight Triethylene glycol 40 parts by weight The film has a thickness of 0.12 mm and a pore size of 0.3 to 0.5. It had a circular hole of μ.

Example 3 Instead of irradiating with an ultraviolet ray irradiating device, an area beam type electron beam irradiating device was used, and irradiation was performed in a nitrogen atmosphere at an accelerating voltage of 200 KV and an absorbed dose of 5 Mrad. A finer porous sintered film was obtained.

Example 4 The amount of coating liquid composition having the same composition as that used in Example 2 was applied.
Apply to cotton woven cloth (cotton broad No. 10000) at 50g / m ²
Using a W ultraviolet ray irradiation device, irradiate 3 times at a speed of 10 m / min to cure, wash in running water at 40 ° C for 5 hours, squeeze with mangle and dry at 50 ° C to obtain a porous coated cloth. .

[Brief description of drawings]

1 to 3 are drawing-substitution electron micrographs showing a structure of a porous material obtained by the production method of the present invention at a magnification of 20000 times.

Claims (1)

[Claims] 1. A composition obtained by mixing an ethylenically unsaturated compound and an alcohol is coated or cast on a substrate, irradiated with an active energy ray to cure the compound, and the alcohol is removed. If desired, the cured product is separated from the substrate, and the amount of alcohol in the composition dissolves the ethylenically unsaturated compound before curing, but the cured product produced upon curing becomes cloudy. A method for producing a porous material, characterized in that it is an amount that causes phase separation.