JPS60257807A - Gas separating molded body - Google Patents

Abstract

PURPOSE:To obtain a gas separating molded body having excellent gas selective separation function, by applying irradiation treatment to the surface of a polymer prepared by polymerizing a silylacetylene compound represented by a specific formula by using ultraviolet rays in a specific wavelength region. CONSTITUTION:A silylacethylene compound, which is reprsented by general formula (wherein R<1> is a hydrogen atom or a 1-8C unsubstituted or substituted monovalent hydrocarbon group and R<2>, R<3> and R<4> are independently a hydrogen atom, a halogen atom, a 1-8C unsubstituted or substituted monovalent hydrocarbon group or a 1-8C alkoxy group), for example, 1-trimethylsilyl-1-propine is dissolved in a solvent and the resulting solution is cast to prepare a molded article. Next, irradiation treatment is applied to the surface of the molded polymer article by using ultraviolet rays in a wavelength region of 105-200nm. By this method, an oxygen enriched membrane high in coefficient of oxygen transmission and the separation factor of oxygen and nitrogen is obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a molded article for gas separation that has good gas permeability and has an excellent selective gas separation function, and in particular, it relates to a molded article for gas separation that has good gas permeability and has an excellent selective gas separation function. The object of the present invention is to provide a molded article for gas separation that is suitable for obtaining a mixed gas.

(Prior Art) Currently, selective gas separation technology using polymer thin films is attracting attention as an alternative to the conventional cryogenic liquefaction separation method and adsorption separation method from the viewpoint of energy saving and pollution prevention. Among these, so-called oxygen enrichment membranes, which can obtain a highly concentrated oxygen-containing mixed gas from air, are expected to have many applications such as medical and combustion-related uses, and their development and commercialization are awaited. . The characteristics required for an oxygen enrichment membrane are that it has a high oxygen/nitrogen separation ability and a high permeation rate (high throughput), but certain homogeneous polymer materials that are currently being prototyped are Relatively high resolution can be expected in applications such as
It has not been put into practical use because the gas permeation rate is extremely low. Furthermore, although a relatively high permeation rate can be obtained by using porous materials, it is difficult to achieve a high oxygen/nitrogen separation ability.

On the other hand, plasma polymerization technology has recently been studied as a means of obtaining an oxygen-enriched film. In other words, this method involves forming an ultra-thin film with high oxygen/nitrogen separation ability on a suitable support with a relatively high permeation rate, such as a homogeneous thin film support or a porous film support, using plasma polymerization technology. The content is to let people know.

The present inventors have repeatedly studied from the viewpoint of a support for a plasma polymerized membrane, and first developed the formula R-02Cj 1. )1 (R)
Forming a low-temperature plasma polymerized film of an organic compound, such as divinyltetramethyldisiloxane gas, on the film surface of a polymer obtained by polymerizing a silylacetylene compound represented by a (in the formula, R is a monovalent organic group). It was confirmed that an extremely good oxygen-enriching membrane (membrane with both high oxygen/nitrogen separation ability and high oxygen permeation rate) could be obtained by this method (Japanese Patent Application No. 58-227996), but it was difficult to put it into practical use. It was discovered that the following problems existed. In other words, in order to obtain good gas separation ability, it is required that the low-temperature plasma polymerized film formed on the film surface of the polymer be uniform and homogeneous, but in general, in plasma polymerization, it is difficult to control the parameters that determine the polymerization conditions. difficult,
In particular, uniform treatment over a wide area (treatment of large-area supports) is difficult; for example, it is affected by the flow state of monomer gas and active species within the reaction system, resulting in large differences in polymerization rate depending on location and large variations in film thickness. . It is similarly difficult to obtain a homogeneous plasma polymerized film, and this is a phenomenon that becomes a special problem when plasma polymerization is carried out for a long time. Possible causes of this include qualitative changes in the applied power that generates the plasma, changes in the concentration of active species, and incorporation of contaminants within the system into the plasma. This makes it difficult to pass through the plasma continuously to deposit a plasma polymerized film, and also makes it difficult to obtain constant, reproducible properties of the plasma polymerized film, ie, industrial production.

ζStructure of the Present Invention) As a result of intensive studies to solve the above-mentioned disadvantages of the conventional technology, the inventors of the present invention have decided to perform irradiation treatment with ultraviolet light having a specific wavelength range instead of the low-temperature plasma of the organic compound gas described above. The present invention was completed based on the discovery that very advantageous results could be obtained by using the method. That is, the present invention has the general formula: R4 individually represents one or more silylacetylene compounds represented by a hydrogen atom, a halogen atom, an unsubstituted or substituted polarized hydrogen group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; The present invention relates to a molded article for gas separation, which is obtained by irradiating the surface of a molded article made from a homopolymer or copolymer obtained by polymerization, or a mixed polymer thereof, with ultraviolet light having a wavelength range of 105 to 200 nm.

Polymers (films) of the above-mentioned silylacetylene compounds usually have poor light resistance, especially resistance to ultraviolet light, and deterioration of mechanical strength and gas separation properties when exposed to sunlight or a small amount of ultraviolet light (near ultraviolet light) from a high-pressure water hook lamp. Because of this property, it is usually impossible to modify this polymer by irradiating it with short-wavelength, high-energy ultraviolet light. However, when such a polymer is irradiated with ultraviolet light having the wavelength range mentioned above, it unexpectedly exhibits an extremely excellent gas separation function as shown in data g2 below, without any disadvantages such as deterioration of mechanical strength. Modified polymer 7 Oxygen permeability coefficient (PO2) = 2 to 4 x 10ctl (s
T P) -an /a/l-sec ・cmHg
Separation coefficient of oxygen and nitrogen (PO2/PN2) = 2.5 to 3
．． It has been established that 5 can be obtained with good reproducibility and that it is extremely advantageous for industrial practical application.

The present invention will be explained in detail below.

In the silylacetylene compound represented by the general formula (1), R1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms, such as a methyl group or an ethyl group.

A propyl group, a butyl group, and a group in which the hydrogen atom of these monovalent hydrocarbon groups is partially substituted with a halogen atom, etc., and R2, R3, and R4 each represent a dihydrogen atom, a halogen atom, or a carbon number. 1 to 8 monovalent hydrocarbon groups such as methyl group, ethyl group, propyl group, butyl group, vinyl group, allyl group, and groups in which the hydrogen atoms of these monovalent hydrocarbon groups are partially substituted with halogen atoms, etc. Carbon number 1-8
Examples of alkoxy groups include methoxy, ethoxy, propoxy, and butoxy groups. Specific examples of such silylacetylene compounds are as follows. However, in the following description (-, Me is a methyl group, gt
each represents an ethyl group.

Me-0==C-8i (Me)3, Et-c=C
-81 (Me).

Me C5081(Et)s, Me-0 MiC-S i
(OMe 13HC=C-8i (Me)3.Me-
C Mi C-8i (Me) az2Me-C Mi C8i (
Me) H2 As a method for polymerizing or copolymerizing one type or a mixture of two or more of the above-mentioned silylacetylene compounds (monomers), in an organic solvent such as toluene or cyclohexane (1), wat6, NbCtll% h
In the presence of a polymerization catalyst such as Tag/-, at a temperature of 30 to 13
A method may be used in which a polymerization reaction is carried out at 0° C., and the produced polymer (copolymer), ie, polysilylacetylene, is purified and recovered by precipitation in excess methanol.

The present invention uses the above-mentioned polymers, copolymers, or two of these.
A molded article (for example, a film having various thicknesses) is prepared by dissolving a mixed polymer of more than one species in an organic solvent such as toluene or cyclohexane, and casting the mixture into an appropriate mold. The polymer film may be formed on a suitable nonwoven fabric, base fabric, porous membrane, or other thin film to facilitate thin film formation. In addition, the porous membrane includes porous polypropylene film, porous polyethylene film, porous polysulfone film,
Examples include porous cellulose acetate film, porous fluorinated ethylene film, and porous polyimide film.

Next, the surface of the polymer molded article is irradiated with ultraviolet light. The light source is not particularly limited as long as it emits monochromatic light, bright line, or continuous light of 105 to 200 nm or less, such as a low-pressure mercury lamp (bright line spectrum: 185 nm).
, 254 nm, 313 im, 355 nm) that emit a bright line spectrum with a wavelength of 200 nm or less is used. In addition, a polymer molded product to be treated is set in a device equipped with a discharge tube or a low-humidity plasma generator, and L i F +Oa 2 is generated between the discharge plasma and the molded product.
F - Cut plasma particles and undesirable short wavelength light with filters and window materials such as sapphire, and
It may be irradiated with ultraviolet light having a wavelength range of 00 nm,
Alternatively, it is also possible to use an ultraviolet laser or the like.

In addition, along with ultraviolet light in the wavelength range of 105 to 200 nm,
Even if a polymer molded product is simultaneously irradiated with light in the wavelength range exceeding 0 im, it will not have much of an adverse effect for a short period of time, but
However, as the irradiation time becomes longer, the deterioration reaction naturally progresses, so it is preferable to carry out the irradiation treatment for 30 minutes or less, although it varies depending on the light intensity from the ultraviolet light source.

The atmosphere used in the ultraviolet light treatment is air, other inorganic gas, organic silane gas, or the like, but is not limited thereto.

Next, specific examples will be given.

Example 1 Toluene 200? One portion of the polymerization catalyst T a OI-s was dissolved in the solution, and then 1-trimethylsilyl-1-propyne Me
-C! Mia-si(Me)3 20. fi' added,
Polymerization was carried out at a temperature of 80° C. for 5 hours. The produced polymer was poured into excess methanol to precipitate and purify it.

The polymer thus obtained was dissolved in toluene to form a solution, and a thin film with a thickness of 2 μm was formed by a casting method. This is designated as sample a. This sample a was placed in a Sbrazier glass tube with mercury and argon vapor sealed in it.
0W low pressure mercury lamp (emission line spectrum/l/: 185n
, m, 254 nm.

313 nm, 365 nm) for 5 minutes under 1 Torr vacuum. This is designated as sample A1. sample a
The permeation rates of oxygen and nitrogen were measured for sample A1, and the oxygen permeability coefficient (PO2) and the oxygen-nitrogen separation coefficient (P
O2/PN2) was charged.

The results are shown in Table 1.

Example 2 Sample a made in the previous example was treated using the same low pressure mercury lamp.
Ultraviolet light treatment was performed for 3 minutes in a nitrogen gas atmosphere of 1 atm. This is sample A2, and the oxygen permeability coefficient (P
O2) and oxygen-nitrogen separation coefficient (PO2/PN2) were calculated. The results are shown in Table 1.

Example 3 The sample a was subjected to ultraviolet light treatment for 20 minutes under 1-1 atmospheric pressure using a 200W low-pressure mercury lamp. This is sample A3
As in the previous example, the oxygen permeability coefficient (PO2) and the oxygen-nitrogen separation coefficient (PO2/PN2J2) were determined. The results are shown in Table 1.

Comparative Example In Example 1, between the low-pressure mercury lamp and sample a,
Irradiation treatment was carried out in the same manner, except that a Vycor filter that did not transmit light of 200 nm or less was provided to prevent light of 185 nm from reaching sample a. This was designated as sample A4, and the oxygen permeability coefficient (PO□) and oxygen-nitrogen separation coefficient (PO2/PN2) were determined in the same manner as in the previous example. The results are shown in Table 1.

Example 4) Luey 300 j'l: Polymerization catalyst TaCl5
'Dissolve and then 1-trimethylsilyl-1-butyne E
t Omi O-3x (M e ) s to 10? and polymerization was carried out at a temperature of 100° C. for 4 hours. The produced polymer was poured into excess methanol to precipitate and purify it.

The polymer thus obtained was dissolved in toluene to form a solution, and a thin film with a thickness of 2 μm was prepared by casting method □. Let's use this as a sample. This sample was set in a low-temperature plasma generator, and after the inside of the apparatus was evacuated to 10 torr, tetramethylsilane gas was introduced and the inside of the system was adjusted and maintained at 0.4 torr on gas flow. Then 13.5
A low-temperature plasma was generated by applying a power of 6 MH 11 kW. At this time, the surface of the sample was covered with a LiF filter, and plasma particles and ultraviolet light in a wavelength range shorter than the ultraviolet wavelength of the present invention were applied to the surface of the sample. prevented from reaching.

The sample treated in this manner is referred to as sample B. For these samples S and B, the oxygen permeability coefficient (PO
2) and the oxygen-nitrogen separation coefficient (PO2/PN2). The results are shown in Table 1.

Claims (1)

[Claims] 1. General formula R2 R'-C4aO-Si-R'' (wherein R1 is a hydrogen atom or an unsubstituted or substituted hydrocarbon group having 1 to 8 carbon atoms, R4 represents one or more silylacetylene compounds represented by dihydrogen atom, halogen atom, unsubstituted or substituted-valent hydrocarbon group having 1 to 8 carbon atoms, or alkoxy group having 1 to 8 carbon atoms) A molded article for gas separation obtained by irradiating the surface of a molded article made from a homopolymer or copolymer obtained by polymerization, or a mixed polymer thereof with ultraviolet light having a wavelength range of 105 to 200 nm.