阅读说明：本技术 一种乙烯-三氟氯乙烯共聚物微孔膜的配方及利用该配方制备微孔膜的方法 (Formula of ethylene-chlorotrifluoroethylene copolymer microporous membrane and method for preparing microporous membrane by using formula ) 是由 钟桂云 刘慧� 吁苏云 代哲振 高林娜 于 2018-09-07 设计创作，主要内容包括：本发明公开了一种制备乙烯-三氟氯乙烯共聚物中空纤维微孔膜的制膜配方,包括20～80wt％的乙烯-三氟氯乙烯共聚物、0.05～50wt％的稀释剂、0.05～15wt％的发泡剂和0.05～25wt％的成核剂。本发明通过在制膜配方中加入发泡剂,能够使乙烯-三氟氯乙烯共聚物微孔膜形成均匀、连续的泡孔,不仅使乙烯-三氟氯乙烯共聚物微孔膜具有良好的力学性能,还是其具有较高的水通量,能够使其适合应用于污水处理和有机溶剂的分离纯化。(The invention discloses a film preparation formula for preparing an ethylene-chlorotrifluoroethylene copolymer hollow fiber microporous film, which comprises 20-80 wt% of ethylene-chlorotrifluoroethylene copolymer, 0.05-50 wt% of diluent, 0.05-15 wt% of foaming agent and 0.05-25 wt% of nucleating agent. According to the invention, the foaming agent is added into the film preparation formula, so that the ethylene-chlorotrifluoroethylene copolymer microporous film can form uniform and continuous foam pores, and the ethylene-chlorotrifluoroethylene copolymer microporous film not only has good mechanical property, but also has higher water flux, and can be suitable for sewage treatment and separation and purification of organic solvents.)

1. A film preparation formula of an ethylene-chlorotrifluoroethylene copolymer microporous film is characterized by comprising the following components in percentage by weight:

the foaming agent is at least one selected from bicarbonate, nitrite, azo compounds, nitrosoamine compounds and sulfonyl hydrazine compounds.

2. A film-forming formulation for an ethylene-chlorotrifluoroethylene copolymer microporous film according to claim 1, wherein the blowing agent comprises:

the bicarbonate is at least one selected from sodium bicarbonate and ammonium bicarbonate;

the nitrite is selected from ammonium nitrite;

the azo compound is at least one selected from azodicarbonamide, azodiisobutyronitrile, isopropyl azodicarboxylate, diethyl azodicarboxylate, diazoaminobenzene and barium azodicarboxylate;

the nitrosamine compound is at least one selected from N, N-dinitrosopentamethylenetetramine and N, N-dimethyl-di-p-xylylenediamine;

the sulfonyl hydrazide compound is at least one selected from 4, 4-disulfonyl hydrazide diphenyl ether, p-benzenesulfonyl hydrazide, 3-disulfonyl hydrazide diphenyl sulfone, 4-diphenyl disulfonyl hydrazide, 1, 3-benzene disulfonyl hydrazide and 1, 4-benzene disulfonyl hydrazide.

3. The film-forming formulation for an ethylene-chlorotrifluoroethylene copolymer microporous film as claimed in claim 2, wherein said blowing agent is selected from azo compounds.

4. A film-forming formulation for an ethylene-chlorotrifluoroethylene copolymer microporous film according to claim 1, wherein:

the ethylene-chlorotrifluoroethylene copolymer is an ethylene-chlorotrifluoroethylene copolymer prepared by 1:1 alternating copolymerization of ethylene and chlorotrifluoroethylene monomers;

the diluent is selected from at least one of dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dioctyl phthalate, diethyl sebacate, glyceryl triacetate and tributyl citrate;

the nucleating agent is selected from at least one of nano clay, nano silicon dioxide, carbon nano tube, calcium carbonate powder, magnesium carbonate powder, nano titanium dioxide and talcum powder.

5. The film-forming formulation for an ethylene-chlorotrifluoroethylene copolymer microporous film according to claim 1, wherein the ethylene-chlorotrifluoroethylene copolymer has a melt index at 275 ℃ and 2.16kg of 5 to 200 g.

6. A method of preparing an ethylene chlorotrifluoroethylene copolymer microporous membrane using the film-forming formulation of claim 1, characterized in that the method comprises:

(1) uniformly mixing ethylene-chlorotrifluoroethylene copolymer, a diluent, a foaming agent and a nucleating agent in proportion, and heating to a molten state at the temperature of 180-270 ℃ to obtain a casting solution;

(2) extruding the membrane casting solution through a die head to form a membrane, so as to obtain a hollow fiber microporous membrane,

or blade-coating the casting solution on a flat plate to obtain a flat microporous membrane;

(3) and (3) placing the hollow fiber microporous membrane and/or the flat microporous membrane in a gel bath at the temperature of 10-150 ℃ for curing, and rinsing with an organic solvent and water to obtain the hollow fiber microporous membrane and/or the flat microporous membrane.

7. A method of preparing an ethylene chlorotrifluoroethylene copolymer microporous membrane using the film-forming formulation of claim 1, characterized in that the method comprises:

(1) uniformly mixing an ethylene-chlorotrifluoroethylene copolymer, a diluent, a foaming agent and a nucleating agent in proportion, and heating to a molten state at the temperature of 190-260 ℃ to obtain a casting solution;

(2) extruding the membrane casting solution through a die head of a double-screw extruder to form a membrane, so as to obtain a hollow fiber microporous membrane, or blade-coating the membrane casting solution on a glass flat plate, so as to obtain a flat microporous membrane;

(3) and (3) placing the hollow fiber microporous membrane and/or the flat microporous membrane in a gel bath at the temperature of 10-150 ℃ for curing, and rinsing with an organic solvent and water to obtain the hollow fiber microporous membrane and/or the flat microporous membrane.

8. A method of preparing an ethylene chlorotrifluoroethylene copolymer microporous membrane using the film-forming formulation of claim 1, characterized in that the method comprises:

(1) uniformly mixing ethylene-chlorotrifluoroethylene copolymer, a diluent, a foaming agent and a nucleating agent in proportion, and heating to a molten state at the temperature of 180-270 ℃ to obtain a casting solution;

(2) extruding the membrane casting solution through a die head of a double-screw extruder to form a membrane, so as to obtain a hollow fiber microporous membrane, or blade-coating the membrane casting solution on a glass flat plate, so as to obtain a flat microporous membrane;

(3) the hollow fiber microporous membrane and/or the flat plate microporous membrane are placed in a gel bath at the temperature of 10-150 ℃ for solidification, and then are rinsed by an organic solvent and water to obtain the hollow fiber microporous membrane and/or the flat plate microporous membrane, wherein the gel bath is selected from at least one of water, ethanol, isobutanol, ethylene glycol and glycerol, and the organic solvent is selected from at least one of ethanol, isopropanol, butanol, acetone and butyl ether.

9. The microporous film of ethylene-chlorotrifluoroethylene copolymer produced by the film-forming formulation according to claim 1, wherein the microporous film of ethylene-chlorotrifluoroethylene has a tensile strength of 1 to 15MPa, an elongation at break of 20 to 150%, and a water permeabilityThe amount of the surfactant is 0.1 to 1200L/m².h。

10. Use of an ethylene chlorotrifluoroethylene copolymer microporous membrane prepared using the film-forming formulation as claimed in claim 1, characterized in that the ethylene chlorotrifluoroethylene microporous membrane is used for sewage treatment and separation and purification of organic solvents.

Technical Field

The invention belongs to the field of high polymer materials, relates to a film preparation formula for preparing a microporous film by a micro-preparation method, and particularly relates to a film preparation formula for preparing an ethylene-chlorotrifluoroethylene copolymer microporous film.

Background

Ethylene chlorotrifluoroethylene copolymer (ECTFE) is an alternating copolymer of chlorotrifluoroethylene and ethylene close to 1:1, and has excellent properties in mechanical strength, heat resistance, chemical resistance, weather resistance and alkali resistance, for example, ethylene chlorotrifluoroethylene copolymer is not soluble in existing organic solvents at temperatures below 120 ℃, is suitable for high-temperature and highly corrosive separation environments, and is a potentially ideal membrane material.

When the ethylene-chlorotrifluoroethylene copolymer is prepared into a film, the ethylene-chlorotrifluoroethylene copolymer film has excellent performances such as high mechanical strength, thermal stability, flame retardance, chemical stability and the like. As for the preparation method of the ethylene-chlorotrifluoroethylene copolymer film, the following reports are reported in the prior art:

U.S. Pat. No. 4,4394460 reports a process for preparing an ethylene-chlorotrifluoroethylene copolymer membrane by dissolving an ethylene-chlorotrifluoroethylene copolymer in chlorotrifluoroethylene at a high temperature, adding silica powder, melt-extruding, quenching to form a membrane, extracting chlorotrifluoroethylene with trichloroethane and removing silica with hot sodium hydroxide to obtain an ethylene-chlorotrifluoroethylene copolymer porous membrane. The method has the advantages of complex process, expensive and toxic diluent chlorotrifluoroethylene, and difficult control of membrane aperture;

the Chinese patent CN1638851A improves the method, changes the diluent with high toxicity into citric acid ethyl ester or triacetyl glycerine, and prepares the ethylene-chlorotrifluoroethylene copolymer porous membrane by a TIPS method. Although the method solves the problem of toxicity of the diluent, the method still has the problems of complex preparation process and difficult control of membrane aperture;

U.S. Pat. No. 5,7247238 also modified the diluent to replace the more toxic diluent with dibutyl phthalate (DBP) to obtain porous membranes of ethylene-chlorotrifluoroethylene copolymer with different pore structures by controlling the quenching temperature. The method has simple process, is easy to control, and can control the pore structure size of the ethylene-chlorotrifluoroethylene copolymer porous membrane, but the prepared ethylene-chlorotrifluoroethylene copolymer porous membranes have spore pore structures, the porosity of the structure is low, and the mechanical property is poor;

chinese patent CN102228805 uses high temperature solvent diethyl phthalate as diluent, and prepares porous membrane of ethylene-chlorotrifluoroethylene copolymer by TIPS method. The membrane prepared by the method has good mechanical property, but the structure of the pores is not easy to control in the preparation process, and the connectivity of the pores is poor, if the membrane is slightly thick, the pores can not be communicated, and the membrane separation can not be carried out;

therefore, there is a need for further improvements in the preparation of microporous ethylene chlorotrifluoroethylene copolymer membranes.

Disclosure of Invention

The first purpose of the invention is to provide a film preparation formula of an ethylene-chlorotrifluoroethylene copolymer microporous film, and the ethylene-chlorotrifluoroethylene copolymer microporous film prepared by the film preparation formula can have uniform and continuous foam pores and can eliminate byproduct HF generated at high temperature.

The second object of the present invention is to provide a method for preparing an ethylene-chlorotrifluoroethylene copolymer hollow fiber microporous membrane using the above membrane-forming formulation.

The third purpose of the invention is to provide a preparation method for preparing the ethylene-chlorotrifluoroethylene copolymer flat microporous membrane by using the membrane preparation formula.

The fourth purpose of the invention is to provide the application of the ethylene-chlorotrifluoroethylene copolymer hollow fiber microporous membrane or the flat microporous membrane prepared by the membrane preparation formula.

The ethylene-chlorotrifluoroethylene copolymer hollow fiber microporous membrane or the flat microporous membrane prepared by the invention has the characteristics of high elongation, high tensile strength, high water flux, good separation effect and the like.

Therefore, the invention adopts the following technical scheme:

a film-making formulation for an ethylene chlorotrifluoroethylene copolymer microporous film, the film-making formulation comprising:

20-80 wt% of ethylene-chlorotrifluoroethylene copolymer;

0.05-50 wt% of diluent;

0.05-15 wt% of foaming agent;

0.05-25 wt% of nucleating agent;

the foaming agent is at least one selected from bicarbonate, nitrite, azo compounds, nitrosoamine compounds and sulfonyl hydrazine compounds.

The foaming agent used in the film forming formulation of the present invention may be at least one selected from the group consisting of bicarbonate, nitrite, azo compounds, nitrosoamine compounds and sulfonyl hydrazide compounds, that is: the compound can be any one or a mixture of any several of bicarbonate, nitrite, azo compounds, nitrosoamine compounds and sulfonyl hydrazine compounds mixed in any proportion.

By bicarbonate is meant a bicarbonate that can be used as a blowing agent. Preferably, the bicarbonate is selected from at least one of sodium bicarbonate and ammonium bicarbonate, namely: can be a mixture of any one or two of sodium bicarbonate and ammonium bicarbonate in any proportion.

The nitrite is a nitrite that can be used as a foaming agent. Preferably, the nitrite is selected from ammonium nitrite.

The azo compound is an azo compound that can be used as a blowing agent. Preferably, the azo-based compound is at least one selected from the group consisting of azodicarbonamide, azobisisobutyronitrile, isopropyl azodicarboxylate, diethyl azodicarboxylate, diazoaminobenzene, and barium azodicarboxylate, that is: can be any one or a mixture of any several of azodicarbonamide, azodiisobutyronitrile, isopropyl azodicarboxylate, diethyl azodicarboxylate, diazoaminobenzene and barium azodicarboxylate in any proportion.

The nitrosoamine compound refers to a nitrosoamine compound that can be used as a blowing agent. Preferably, the nitrosamine-based compound is selected from at least one of N, N-dinitrosopentamethylenetetramine and N, N-dimethyl-diterephthalandiamine, that is: it may be any one or a mixture of two selected from the group consisting of N, N-dinitrosopentamethylenetetramine and N, N-dimethyl-diterephthalandiamine in any ratio.

The sulfonyl hydrazide compound refers to a sulfonyl hydrazide compound which can be used as a foaming agent. Preferably, the sulfonyl hydrazide compound is at least one selected from the group consisting of 4, 4-disulfonyl hydrazide diphenyl ether, p-benzenesulfonyl hydrazide, 3-disulfonyl hydrazide diphenyl sulfone, 4-diphenyl disulfonyl hydrazide, 1, 3-benzene disulfonyl hydrazide and 1, 4-benzene disulfonyl hydrazide, that is: can be any one or a mixture of any several of 4, 4-disulfonyl hydrazide diphenyl ether, p-benzenesulfonyl hydrazide, 3-disulfonyl hydrazide diphenyl sulfone, 4-diphenyldisulfonyl hydrazide, 1, 3-benzenesulfonyl hydrazide and 1, 4-benzenesulfonyl hydrazide in any proportion.

In order to enable the microporous membrane of the ethylene-chlorotrifluoroethylene copolymer prepared by the membrane preparation formula to have uniform and continuous pores, the ethylene-chlorotrifluoroethylene copolymer is preferably an ethylene-chlorotrifluoroethylene copolymer prepared by the 1:1 alternating copolymerization of ethylene and chlorotrifluoroethylene monomers, and is further preferably an ethylene-chlorotrifluoroethylene copolymer prepared by the 1:1 alternating copolymerization of ethylene and chlorotrifluoroethylene monomers, wherein the melt index of the ethylene-chlorotrifluoroethylene copolymer at 275 ℃ and 2.16kg is 5-200 g.

The diluent used in the film-forming formulation of the present invention may be at least one selected from the group consisting of dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dioctyl phthalate, diethyl sebacate, triacetin and tributyl citrate, that is: can be any one or a mixture of any several of dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dioctyl phthalate, diethyl sebacate, glyceryl triacetate and tributyl citrate which are mixed in any proportion.

The nucleating agent used in the film preparation formula of the invention can be at least one selected from nano clay, nano silicon dioxide, carbon nano tube, calcium carbonate powder, magnesium carbonate powder, nano titanium dioxide and talcum powder, namely: can be any one or a mixture of any several of nano clay, nano silicon dioxide, carbon nano tube, calcium carbonate powder, magnesium carbonate powder, nano titanium dioxide, kaolin powder and talcum powder which are mixed in any proportion.

In the invention, the higher the content of the ethylene-chlorotrifluoroethylene copolymer is, the better the mechanical property of the finally prepared microporous membrane is, but the porosity can be reduced and the membrane forming is not good, and in order to obtain the microporous membrane with better mechanical property, overall performances such as porosity, water flux and the like, the mass percent of the ethylene-chlorotrifluoroethylene copolymer in the membrane preparing formula is controlled to be 20-80 wt%.

In order to obtain a uniform membrane casting solution and make the membrane casting solution easily extruded from a die head, the mass percentage of the diluent in the membrane preparation formula is controlled to be 0.05-50 wt%.

The microporous membrane has the advantages that the amount of the foaming agent is too small, the number of cells of the microporous membrane is too large, the foaming agent is too much, the mechanical strength of the microporous membrane is reduced, and in order to obtain the microporous membrane with better mechanical properties, porosity, water flux and other overall properties, the mass percentage of the foaming agent in the membrane preparation formula is controlled to be 0.05-15 wt%.

The microporous membrane with too small amount of the nucleating agent has few cells, too many nucleating agents, the content of the ethylene-chlorotrifluoroethylene copolymer is reduced, the mechanical strength of the membrane is reduced, and in order to obtain the microporous membrane with better mechanical property, porosity, water flux and other overall properties, the mass percentage of the nucleating agent in the membrane preparation formula is controlled to be 0.05-25 wt%.

The method for preparing the ethylene-chlorotrifluoroethylene copolymer microporous membrane by using the membrane preparation formula is characterized by comprising the following steps of:

(1) uniformly mixing ethylene-chlorotrifluoroethylene copolymer, a diluent, a foaming agent and a nucleating agent in proportion, and heating to a molten state at the temperature of 180-270 ℃ to obtain a casting solution;

(2) extruding the membrane casting solution through a die head to form a membrane, so as to obtain a hollow fiber microporous membrane,

or blade-coating the casting solution on a flat plate to obtain a flat microporous membrane;

(3) and (3) placing the hollow fiber microporous membrane and/or the flat microporous membrane in a gel bath at the temperature of 10-150 ℃ for curing, and rinsing with an organic solvent and water to obtain the hollow fiber microporous membrane and/or the flat microporous membrane.

The method for preparing the ethylene-chlorotrifluoroethylene copolymer microporous membrane by using the membrane preparation formula is characterized by comprising the following steps of:

(1) uniformly mixing an ethylene-chlorotrifluoroethylene copolymer, a diluent, a foaming agent and a nucleating agent in proportion, and heating to a molten state at the temperature of 190-260 ℃ to obtain a casting solution;

(2) extruding the membrane casting solution through a die head of a double-screw extruder to form a membrane, so as to obtain a hollow fiber microporous membrane, or blade-coating the membrane casting solution on a glass flat plate, so as to obtain a flat microporous membrane;

(3) and (3) placing the hollow fiber microporous membrane and/or the flat microporous membrane in a gel bath at the temperature of 10-150 ℃ for curing, and rinsing with an organic solvent and water to obtain the hollow fiber microporous membrane and/or the flat microporous membrane.

The method for preparing the ethylene-chlorotrifluoroethylene copolymer microporous membrane by using the membrane preparation formula is characterized by comprising the following steps of:

(1) uniformly mixing ethylene-chlorotrifluoroethylene copolymer, a diluent, a foaming agent and a nucleating agent in proportion, and heating to a molten state at the temperature of 180-270 ℃ to obtain a casting solution;

(2) extruding the membrane casting solution through a die head of a double-screw extruder to form a membrane, so as to obtain a hollow fiber microporous membrane, or blade-coating the membrane casting solution on a glass flat plate, so as to obtain a flat microporous membrane;

(3) the hollow fiber microporous membrane and/or the flat plate microporous membrane are placed in a gel bath at the temperature of 10-150 ℃ for solidification, and then are rinsed by an organic solvent and water to obtain the hollow fiber microporous membrane and/or the flat plate microporous membrane, wherein the gel bath is selected from at least one of water, ethanol, isobutanol, ethylene glycol and glycerol, and the organic solvent is selected from at least one of ethanol, isopropanol, butanol, acetone and butyl ether.

The temperature range of the casting solution prepared by the preparation method is 180-270 ℃, and preferably 190-260 ℃. The temperature selection for a particular process implementation is related to the selection of the diluent.

The ethylene-chlorotrifluoroethylene microporous membrane prepared by the invention comprises a hollow fiber microporous membrane and a flat microporous membrane, and has the tensile strength of 1-15 MPa, the elongation at break of 20-150% and the water flux of 0.1-1200L/m².h。

The preferable ethylene-chlorotrifluoroethylene microporous membrane comprises a hollow fiber microporous membrane and a flat microporous membrane, the tensile strength is 2-12 MPa, the elongation at break is 50-120%, and the water flux is 1-1000L/m².h。

The ethylene-chlorotrifluoroethylene microporous membrane prepared by the invention is suitable for sewage treatment and separation and purification of organic solvents.

Compared with the prior art, the ethylene-chlorotrifluoroethylene copolymer film preparation formula provided by the invention is suitable for preparing the ECTFE microporous film by a thermal phase separation method, and has good water flux while maintaining the excellent mechanical property of the microporous film.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to limit the invention to these embodiments. It will be appreciated by those skilled in the art that the present invention encompasses all alternatives, modifications and equivalents as may be included within the scope of the claims.