CN106178978A - A kind of flexible silicone rubber composite film and its preparation method and application - Google Patents

Abstract

The invention relates to a flexible silicone rubber composite membrane and a preparation method and application thereof, belonging to the field of composite membranes. A flexible silicon rubber composite membrane is composed of a flexible metal wire mesh and a silicon rubber polymer; the silicone rubber polymer is used as a continuous phase and is tightly combined with a flexible metal wire mesh used as a support body, and the silicone rubber polymer is completely filled between the longitude and latitude structures of the flexible metal wire mesh to form the flexible silicone rubber composite membrane with a continuous interpenetrating network structure. The flexible silicone rubber composite membrane for separating hydrocarbon gas provided by the invention has good hydrocarbon gas separation performance, mechanical strength and flexibility, and can keep the stability of structure and performance for a long time at a higher temperature after thermal stabilization treatment. The preparation method of the flexible silicone rubber composite membrane for separating hydrocarbon gas provided by the invention has the advantages of simple process, easy control, realization of continuous production, easy process amplification and industrial production prospect.

Description

A kind of flexible silicone rubber composite film and its preparation method and application

technical field

The invention relates to a flexible silicone rubber composite membrane, a preparation method and application thereof, and belongs to the field of composite membranes.

Background technique

Hydrocarbon gas is an important basic organic chemical raw material, which usually exists in a large amount in the form of oil and gas in the associated gas of oil and gas fields, or is generated in the process of oil extraction, refining, storage and transportation. The main components of oil and gas are mixtures of hydrocarbon gases and air. The random discharge of oil and gas will lead to a series of environmental problems such as the greenhouse effect and photochemical smog, and the direct combustion of oil and gas is a serious waste of oil resources. Therefore, the separation and recovery of oil and gas can not only realize the full utilization of resources, but also purify the air and reduce the harm to the environment. At present, the most commonly used method for oil and gas separation is cryogenic separation, but its equipment is complicated, energy consumption is high, and efficiency is low. Gas membrane separation technology has the advantages of low energy consumption, environmental friendliness, high efficiency, and low cost. As an emerging technology in the field of hydrocarbon gas recovery, it has broad development prospects.

High-performance membrane materials are the core of membrane separation technology. To achieve the separation and recovery of light hydrocarbon gases requires membrane materials that can more easily pass through macromolecular and easily compressible hydrocarbon gases. The molecular chain of silicone rubber has a helical structure, high degree of curl, low molecular rigidity, flexible skeleton, and low glass transition temperature. At the same time, the intermolecular force of silicone rubber is weak, and the ability to dissolve hydrocarbons is strong, which is more conducive to the permeation of macromolecular hydrocarbon gases. Therefore, silicone rubber can be used as an ideal membrane material for hydrocarbon recovery. At present, a lot of research on silicone rubber membranes is dedicated to the preparation of non-supported silicone rubber membranes or composite silicone rubber membranes supported by organic materials such as non-woven fabrics and polysulfone. Poor performance, poor solvent resistance and low service life. Inorganic supports such as ceramic tubes and porous stainless steel have the advantages of high flux, high mechanical strength, good thermal stability, and good chemical stability, and are ideal support materials for preparing gas separation membranes. However, these commonly used The inorganic support has poor flexibility and brittleness, and cannot be curled. The reprocessing ability of the prepared membrane material is weak, and the corresponding module packing density is lower than that of spiral wound or hollow fiber membrane modules commonly used in gas separation.

In order to improve the mechanical strength, chemical stability and flexibility of the silicone rubber composite membrane, prolong the service life, and promote the development of the silicone rubber membrane in the field of hydrocarbon gas separation, research and development have high strength, long service life, high chemical stability and thermal It is of great significance to stabilize the flexible silicone rubber composite membrane for the separation of hydrocarbon gases and improve its preparation process.

Contents of the invention

In order to solve the above technical problems, the present invention provides a flexible silicone rubber composite membrane.

A flexible silicone rubber composite membrane, the flexible silicone rubber composite membrane is composed of a flexible wire mesh and a silicone rubber polymer; the silicone rubber polymer is closely combined with the flexible metal mesh as a support as a continuous phase, and is completely filled in the flexible A flexible silicone rubber composite film with a continuous interpenetrating network structure is formed between the warp and weft structures of the wire mesh.

The flexible silicon rubber composite membrane of the present invention is made of flexible inorganic support, i.e. a flexible wire mesh and a silicone rubber polymer; the silicone rubber polymer in the composite membrane is completely filled in the support, and the two are closely combined, and the silicone rubber polymerizes As the continuous phase and the warp and weft of the support, an interpenetrating network continuous structure is formed, which ensures the structural stability, high permeability and high selectivity of the silicone rubber composite membrane; the flexible wire mesh makes the silicone rubber composite membrane have good Mechanical strength and thermal and chemical stability, and endow the silicone rubber membrane with good flexibility and reprocessing ability, and prepare a membrane module with a large packing density.

In the above technical solution, the silicone rubber polymer is condensation-type silicone rubber or addition-type silicone rubber.

The above-mentioned flexible silicone rubber composite membrane is preferably prepared according to the following scheme: the silicone rubber membrane-making liquid is covered on a flexible wire mesh, and it is cross-linked and solidified to obtain a silicone rubber composite membrane; the gained silicone rubber composite membrane is subjected to heat treatment,

The heat treatment conditions are: place the cross-linked and cured silicone rubber composite film in a heating furnace, and conduct heat treatment under the protection of inert gas; The temperature is 200-500°C, and the constant temperature time is 0-2h; after reaching the final temperature, a mixed gas with an oxygen content of 0.3-3% is introduced, the temperature is kept constant for 0.5-2h, the inert gas protection is switched, and the temperature is naturally cooled to room temperature to obtain flexible silicon. Rubber composite membrane.

Further, preferably, the mesh of the flexible wire mesh is 200-500 mesh.

In the above technical solution, the mixed gas in the "mixed gas with an oxygen content of 0.3-3%" is a mixed gas of oxygen and inert gas.

In the above technical solution, the inert gas is preferably argon or nitrogen.

In the above technical scheme, the preferred inert gas flow rate is 50-70mL/min, the heating rate is 0.5-2°C/min, the final heat treatment temperature is 300-400°C, and the constant temperature time is 0.5-1.5h; Mixed gas with an oxygen content of 0.5-2%, constant temperature for 0.5-1h.

In the above-mentioned technical scheme, it is preferable that the film-forming liquid is composed of silicone rubber monomer, catalyst, crosslinking agent and solvent, wherein the concentration of silicone rubber monomer is 10 to 40wt.%; further, preferably the concentration of silicone rubber monomer The concentration is 15-30wt.%.

Further, it is preferred that the silicone rubber monomer is polydimethylsiloxane (PDMS), polytrimethylsilapropyne (PTMSP), polyvinyltrimethylsilane (PVTMS) and polyvinyldimethylsilane One of silane (PVDMS).

In the above technical solution, the solvent is preferably one of n-hexane, n-heptane, n-octane, benzene, toluene or xylene.

When the silicone rubber composite membrane polymer is addition-type silicone rubber, in the membrane-forming solution, the catalyst is a platinum complex, a ruthenium complex or a rhodium complex; the crosslinking agent is formazan One of phenyltriethoxysilane, phenyltrimethoxysilane (PTMOS), octyltrimethoxysilane (OTMOS), γ-aminopropyl triethoxysilane; the silicone rubber monomer and catalyst The mass ratio of the silicone rubber monomer to the crosslinking agent is 1:1 to 1:0.02, and the mass ratio of the silicone rubber monomer to the crosslinking agent is 1:1 to 1:0.05.

In the above technical scheme, the platinum complex is H ₂ PtCl; the ruthenium complex is carbonyl hydrogenated (tetrahydroborane) ruthenium (II); the rhodium complex is acetylacetone carbonyltriphenyl Phosphine rhodium(I).

When the silicone rubber composite membrane polymer is condensation type silicone rubber, in the membrane forming solution, the catalyst is one of titanate coupling agent and organotin compound; the crosslinking agent is positive One of ethyl silicate, tetraethyl orthosilicate, polyalkoxysilane, polybutanone oximinosilane, polyacetoxysilane, polyaminosilane, polyamidosilane, polyisopropenoxysilane species; the mass ratio of the silicone rubber monomer to the catalyst is 1:0.01 to 1:0.1, and the mass ratio of the silicone rubber monomer to the crosslinking agent is 1:0.01 to 1:0.5.

In the above technical solution, the organotin compound is dibutyl dilaurate or dibutyltin dichloride.

The flexible silicone rubber composite membrane of the present invention is preferably one of nickel mesh, stainless steel mesh, copper mesh and aluminum mesh.

Another object of the present invention is to provide a method for preparing the above-mentioned flexible silicone rubber composite membrane.

A preparation method of a flexible silicone rubber composite membrane is to cover a silicone rubber membrane-making liquid on a flexible wire mesh, make it cross-linked and solidified to obtain a silicone rubber composite membrane; heat-treat the obtained silicone rubber composite membrane,

The heat treatment conditions are: place the cross-linked and cured silicone rubber composite film in a heating furnace, and conduct heat treatment under the protection of inert gas; The temperature is 200-500°C, and the constant temperature time is 0-2h; after reaching the final temperature, a mixed gas with an oxygen content of 0.3-3% is introduced, the temperature is kept constant for 0.5-2h, the inert gas protection is switched, and the temperature is naturally cooled to room temperature to obtain flexible silicon. rubber composite membrane,

Wherein, the silicone rubber monomer is polydimethylsiloxane (PDMS), polytrimethylsilylpropyne (PTMSP), polyvinyltrimethylsilane (PVTMS) and polyvinyldimethylsilane ( PVDMS); the mesh number of the flexible wire mesh is 200-500 mesh.

In the above technical solution, the mixed gas in the "mixed gas with an oxygen content of 0.3-3%" is a mixed gas of oxygen and inert gas.

In the above technical solution, the inert gas is preferably argon or nitrogen.

In the above technical scheme, the preferred inert gas flow rate is 50-70mL/min, the heating rate is 0.5-2°C/min, the final heat treatment temperature is 300-400°C, and the constant temperature time is 0.5-1.5h; Mixed gas with an oxygen content of 0.5-2%, constant temperature for 0.5-1h.

In the preparation method of the flexible silicone rubber composite membrane of the present invention, it is preferred that the film-making liquid is composed of silicone rubber monomers, catalysts, crosslinking agents and solvents, wherein the concentration of silicone rubber monomers is 10 to 40wt.%; further , preferably the concentration of the silicone rubber monomer is 15-30wt.%.

In the above technical solution, the solvent is preferably one of n-hexane, n-heptane, n-octane, benzene, toluene and xylene.

The method of the invention can be used to prepare condensation type silicone rubber or addition type silicone rubber composite film.

When the silicone rubber composite membrane polymer is addition-type silicone rubber, in the membrane-forming solution, the catalyst is a platinum complex, a ruthenium complex or a rhodium complex; the crosslinking agent is formazan One of phenyltriethoxysilane, phenyltrimethoxysilane (PTMOS), octyltrimethoxysilane (OTMOS), γ-aminopropyltriethoxysilane; the silicone rubber monomer and catalyst The mass ratio of the silicone rubber monomer to the crosslinking agent is 1:1 to 1:0.02, and the mass ratio of the silicone rubber monomer to the crosslinking agent is 1:1 to 1:0.05.

In the above technical scheme, the platinum complex is H ₂ PtCl; the ruthenium complex is carbonyl hydrogenated (tetrahydroborane) ruthenium (II); the rhodium complex is acetylacetone carbonyltriphenyl Phosphine rhodium(I).

When the silicone rubber composite membrane polymer is condensation type silicone rubber, in the membrane forming solution, the catalyst is one of titanate coupling agent and organotin compound; the crosslinking agent is positive One of ethyl silicate, tetraethyl orthosilicate, polyalkoxysilane, polybutanone oximinosilane, polyacetoxysilane, polyaminosilane, polyamidosilane, polyisopropenoxysilane species; the mass ratio of the silicone rubber monomer to the catalyst is 1:0.01 to 1:0.1, and the mass ratio of the silicone rubber monomer to the crosslinking agent is 1:0.01 to 1:0.5.

In the above technical solution, the organotin compound is dibutyltin dilaurate or dibutyltin dichloride.

The preparation method of flexible silicone rubber composite membrane of the present invention preferably described silicone rubber composite membrane is prepared by the following method:

The composite film is prepared on a flexible wire mesh by dipping method, scraping method, spraying method or mold forming method, and the prepared composite film is evaporated at room temperature -80°C for 1-24h, and cross-linked at 80-180°C Curing for 3 to 12 hours to obtain a silicone rubber composite film.

Further, a preferred technical solution of the preparation method of the flexible silicone rubber composite membrane of the present invention is:

A preparation method of a flexible silicone rubber composite membrane, comprising the following processing steps:

① Configure the film-making solution: put the silicone rubber monomer, catalyst, and crosslinking agent in the solvent, wherein the concentration of the silicone rubber monomer is 10-40wt.%;

② Composite film preparation: Prepare a composite film on a flexible wire mesh by dipping, scraping, spraying or mold forming, and evaporate the prepared composite film at room temperature -80°C for 1 to 24 hours. ~180°C cross-linking and curing for 3~12 hours to prepare a silicone rubber composite film;

③Heat treatment: place the cross-linked and cured silicone rubber composite film in a heating furnace for heat treatment under the protection of inert gas; 200～500℃, the constant temperature time is 0～2h; when the final temperature is reached, a mixed gas with an oxygen content of 0.3～3% is introduced, the temperature is kept constant for 0.5～2h, the inert gas protection is switched, and the temperature is naturally cooled to room temperature to obtain flexible silicone rubber Composite film,

Wherein, the silicone rubber monomer is polydimethylsiloxane (PDMS), polytrimethylsilylpropyne (PTMSP), polyvinyltrimethylsilane (PVTMS) and polyvinyldimethylsilane ( One of PVDMS).

In the above technical scheme, in step ①, when the silicone rubber composite membrane polymer is addition-type silicone rubber, in the membrane-forming liquid, the catalyst is a platinum complex, a ruthenium complex or a rhodium complex The crosslinking agent is one of methyltriethoxysilane, phenyltrimethoxysilane (PTMOS), octyltrimethoxysilane (OTMOS), and γ-aminopropyltriethoxysilane; The mass ratio of the silicone rubber monomer to the catalyst is 1:1˜1:0.02, and the molar ratio of the silicone rubber monomer to the crosslinking agent is 1:1˜1:0.05.

In the above technical solution, in step ①, when the silicone rubber composite membrane polymer is condensation type silicone rubber, in the membrane forming solution, the catalyst is one of titanate coupling agent and organotin; The cross-linking agent is ethyl orthosilicate, tetraethyl orthosilicate, polyalkoxysilane, polybutanone oximinosilane, polyacetoxysilane, polyaminosilane, polyamidosilane, polyiso One of acryloxysilane; the molar ratio of the silicone rubber monomer to the catalyst is 1:0.01 to 1:0.1, and the mass ratio of the silicone rubber monomer to the crosslinking agent is 1:0.01 to 1:0.5 .

Another object of the present invention is to provide the application of the flexible silicone rubber composite membrane as a separation membrane, especially as a separation membrane for separating hydrocarbon gases, wherein the hydrocarbon gases are C _1～8 alkanes, C _1～ One of ₈ alkenes and C _1-8 alkynes.

The C _1-8 alkanes, C _1-8 alkenes and C _1-8 alkynes in the present invention all include their respective linear and branched structures.

The effects and benefits of the present invention are: the flexible silicone rubber composite membrane for separating hydrocarbon gases provided by the present invention has good hydrocarbon gas separation performance, mechanical strength and flexibility, and after thermal stabilization treatment, it can be used at higher temperatures Long-term stability of structure and performance is maintained, which solves the problems of low mechanical strength, poor solvent resistance and thermal stability, and low service life of the existing organic support composite silicone rubber membrane, and the poor flexibility of the existing inorganic support composite silicone rubber membrane. Problems of weak processability and low packing density of components. The preparation method of the flexible silicone rubber composite membrane for separating hydrocarbon gas proposed by the present invention optimizes the preparation process of the traditional silicone rubber membrane, the process is simple, easy to control, continuous production can be realized, and the process is easy to scale up, which has industrialization production prospects.

Description of drawings

Fig. 1 is the optical electron micrograph (1000 times magnification) of the 325-mesh stainless steel screen support composite membrane prepared in Example 1 of the present invention. The surface of the composite membrane is light yellow after the stainless steel wire mesh is heated. The silicone rubber in the composite membrane is completely filled in the stainless steel mesh support. continuous structure.

Fig. 2 is an optical electron micrograph (magnified 1000 times) of the 500-mesh copper mesh supported composite film prepared in Example 11 of the present invention. The surface of the composite membrane is slightly dark brass, and the silicone rubber in the composite membrane is completely filled in the copper mesh support.

Fig. 3 is a scanning electron microscope surface photo (magnified 100 times) of the 500-mesh copper mesh supported composite film prepared in Example 11 of the present invention. The surface of the composite membrane is uniform without pinholes or defects, and the warp and weft distribution of the support can be observed.

Fig. 4 is a scanning electron microscope cross-sectional photo (magnified 1000 times) of the 500-mesh copper mesh supported composite membrane prepared in Example 11 of the present invention. Silicone rubber is completely filled between the warp and weft of the support, and the external force of liquid nitrogen brittle fracture during electron microscope sample preparation has caused small gaps and cracks between the copper mesh and the support in the cross-sectional photos.

The digital photo of the composite membrane prepared in Fig. 5 Example 17. The composite membrane presents the color of the stainless steel screen at this time, and the surface of the composite membrane is uniform and flat, and the warp and weft distribution of the support screen can be observed, without pinholes, cracks, defects, etc.

The digital photo of the composite membrane prepared in Fig. 6 Example 28. The appearance of the composite membrane is similar to that in Figure 5, but the color of the membrane is slightly darker.

detailed description

The following non-limiting examples can enable those skilled in the art to understand the present invention more fully, but do not limit the present invention in any way.

The test methods described in the following examples, unless otherwise specified, are conventional methods; the reagents and materials, unless otherwise specified, can be obtained from commercial sources.

Example 1

Mix 10g of PDMS (as a silicone rubber monomer) with H ₂ PtCl (as a catalyst) and methyltriethoxysilane (as a crosslinking agent), the mass ratio of PDMS to H ₂ PtCl is 1:0.02, PDMS and methyl The mass ratio of triethoxysilane is 1:0.5. After mixing, use n-hexane as a solvent to prepare a film-making solution with a PDMS concentration of 20wt.%, and prepare a composite film on a 325-mesh stainless steel screen by dipping method. The composite film after dipping The film was evaporated at room temperature for 6 hours, cross-linked and cured at 120°C for 8 hours to obtain a composite PDMS film; the cross-linked and cured PDMS film was placed in a heating furnace for heat treatment, with argon as the carrier gas, and the flow rate was 40ml/ min, the heating rate is 2°C/min, the final heat treatment temperature is 280°C, and the constant temperature time is 1h; after the final temperature is reached, an oxygen-nitrogen mixture with an oxygen content of 1% is introduced, and the temperature is kept constant for 1h, and the argon protection is switched, and the temperature is naturally lowered to room temperature to prepare a flexible PDMS composite membrane for separating hydrocarbon gases. Taking propylene/nitrogen and propane/nitrogen systems as examples, the hydrocarbon gas separation performance of the flexible silicone rubber composite membrane at 30 °C is shown in Table 1.

Example 2-4

The procedure of Example 1 was repeated for the silicone rubber monomers specified in Table 1 below, and the test results are listed in Table 1 below.

Table 1

Example 5-6

The procedure of Example 1 was repeated with the catalysts specified in Table 2 below, where the test results are listed.

Table 2

Example 7-9

The procedure of Example 1 was repeated with the cross-linking agents specified in Table 3 below, where the test results are listed.

table 3

Examples 10-12

The procedure of Example 1 was repeated with the flexible wire mesh specified in Table 4 below, where the test results are listed.

Table 4

Examples 13-16

The procedure of Example 1 was repeated with the solvents specified in Table 5 below, where the test results are listed.

table 5

Example 17

Mix PDMS (as a silicone rubber monomer), tetraethyl orthosilicate (as a crosslinking agent) and dibutyltin dilaurate (as a catalyst) at a molar ratio of 1:0.2:0.02, and then prepare with xylene as a solvent A film-making solution with a PDMS concentration of 35wt.% was prepared, and a composite film was prepared on a 300-mesh stainless steel mesh by scraping method. The impregnated composite film was evaporated at room temperature for 1 hour, and cross-linked and cured at 130°C for 10 hours to obtain a composite PDMS. Membrane: Put the cross-linked and cured PDMS membrane into a heating furnace for heat treatment, using nitrogen as the carrier gas, the flow rate is 60ml/min, the heating rate is 1°C/min, the final temperature of heat treatment is 300°C, and the constant temperature time is 0.5h ; After reaching the final temperature, pass in an oxygen-nitrogen mixture with an oxygen content of 0.5%, keep the temperature for 2 hours, switch to nitrogen protection, and naturally cool down to room temperature to prepare a flexible PDMS composite membrane for separating hydrocarbon gases. Taking propylene/nitrogen and propane/nitrogen systems as examples, the hydrocarbon gas separation performance of the flexible silicone rubber membrane at 30 °C is shown in Table 6.

Examples 18-20

The procedure of Example 17 was repeated as specified in Table 6 below, where the test results are listed.

Table 6

Examples 21-27

The procedure of Example 17 was repeated with the crosslinkers specified in Table 7 below, the results of which are presented in Table 7.

Table 7

Example 28

The procedure of Example 17 was repeated with the catalyst specified in Table 8 below, where the test results are listed.

Table 8

Claims (8)

1. a flexible silicone rubber composite membrane, it is characterised in that:

Described flexible silicone rubber composite membrane is made up of flexible metal silk screen and silastic polymer；Silastic polymer is as continuously Combine closely with the flexible metal silk screen as supporter, be completely filled between the longitude and latitude structure of flexible metal silk screen, shape Become there is the flexible silicone rubber composite membrane of continuous inierpeneirating network structure.

Composite membrane the most according to claim 1, it is characterised in that: described flexible metal silk screen is nickel screen, stainless (steel) wire, copper One in net, aluminum net.

3. the preparation method of flexible silicone rubber composite membrane described in claim 1, it is characterised in that: silicone rubber preparation liquid is overlying on soft On property metal gauze so that it is carry out crosslinking curing, obtain composite silicone rubber membrane；Gained composite silicone rubber membrane is carried out heat treatment,

Heat treatment condition is: by the composite silicone rubber membrane after crosslinking curing in heating furnace, carries out heat under inert gas shielding Process；Inert gas flow is 30～70mL/min, and heating rate is 0.1～3 DEG C/min, and heat treatment final temperature is 200～500 DEG C, constant temperature time is 0～2h；After reaching final temperature, it is passed through the gaseous mixture that oxygen content is 0.3～3%, constant temperature 0.5～2h, switching Inert gas shielding, is naturally cooling to room temperature, prepares flexible silicone rubber composite membrane.

Method the most according to claim 3, it is characterised in that: described silicone rubber preparation liquid by rubber monomer, catalyst, Cross-linking agent and solvent are constituted, and wherein, described rubber monomer is polydimethylsiloxane, poly-trimethyl silicane propine, polyvinyl One in trimethyl silane or polyvinyl dimethylsilane, the concentration of rubber monomer is 10～40wt.%.

Method the most according to claim 4, it is characterised in that: described catalyst is platinum complex, ruthenium complex or rhodium network Compound；Described cross-linking agent is MTES, phenyltrimethoxysila,e (PTMOS), octyl group trimethoxy silane (OTMOS), the one in γ aminopropyltriethoxy silane；The mass ratio of described rubber monomer and catalyst be 1:1～ 1:0.02, described rubber monomer is 1:1～1:0.05 with the mass ratio of cross-linking agent.

Method the most according to claim 4, it is characterised in that: described catalyst is titanate coupling agent, organotin chemical combination One in thing；Described cross-linking agent is tetraethyl orthosilicate, tetraethyl orthosilicate, many alkoxy silanes, many diacetylmonoxime base silane, many One in acetoxylsilane, many amino containing silanes, multiamide base silane, many iso-propenyloxysilanes；Described rubber monomer Being 1:0.01～1:0.1 with the mass ratio of catalyst, described rubber monomer is 1:0.01～1 with the mass ratio of cross-linking agent: 0.5。

Method the most according to claim 3, it is characterised in that: described composite silicone rubber membrane is prepared as follows:

Infusion process, knife coating, spraying process or mould forming method is used to prepare composite membrane on the net at flexible wire, by prepare Composite membrane carries out the solvent evaporation of 1～24h at room temperature-80 DEG C, at 80～180 DEG C of crosslinking curings 3～12h, prepares silicone rubber Composite membrane.

8. flexible silicone rubber composite membrane described in claim 1 is as the application separating film, it is characterised in that: described flexible silicone rubber Composite membrane is used for separating hydrocarbons gas, and described hydrocarbon gas is C_1～8Alkane, C_1～8Alkene and C_1～8One in alkynes.