Preparation method of polytetrafluoroethylene flexible stretch film material

Abstract

The invention provides a preparation method of a material for a polytetrafluoroethylene flexible stretch film, which comprises the following steps: adding ionized water, perfluoropolyether ammonium carboxylate, paraffin and acrylic acid into a polymerization kettle, vacuumizing, carrying out replacement treatment, carrying out polymerization reaction, adding di-tert-butyl peroxide into the polymerization kettle, stirring, and carrying out heat preservation to obtain the material for the polytetrafluoroethylene flexible stretch film. Adding a tetrafluoroethylene monomer into a polymerization kettle, and continuously adding the ferrous naphthenate solution into the polymerization kettle for constant-pressure polymerization; and 3, gradually adding all tetrafluoroethylene into the reaction kettle, pausing stirring, releasing the pressure of gas in the kettle to micro-positive pressure, filling nitrogen, adding isocyano ethyl methacrylate and the residual ferrous naphthenate into the reaction kettle, reacting for 1-2 hours, terminating the reaction, cooling, discharging, condensing, washing and drying to obtain the product. The powder resin for the polytetrafluoroethylene flexible stretching film is obtained. According to the material prepared by the invention, the polytetrafluoroethylene stretch film has the characteristics of small pore diameter, uniform distribution and high mechanical strength at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorine-containing plastics and preparation methods thereof, and particularly relates to a preparation method for polytetrafluoroethylene flexible stretch film material. Background Art

[0002] Membrane technology has been widely used in people's lives, industrial fields and scientific research. A variety of polymer material stretch membranes have been developed. Polytetrafluoroethylene has extremely good chemical stability and extremely wide temperature resistance, making it an ideal material for preparing high-performance stretch membranes. Polytetrafluoroethylene stretch porous membranes are made by extruding and stretching polytetrafluoroethylene fine powder to form fibers from powder particles. They have high requirements for the mechanical properties of the powder. The existing polytetrafluoroethylene has a large pore size of the fiber interwoven mesh structure due to the crystallinity of the material itself, and is prone to uneven distribution, which affects the mechanical strength. Therefore, obtaining high-performance and multifunctional polytetrafluoroethylene stretch membrane modified materials has become a research focus. Summary of the invention

[0003] The invention provides a method for preparing a material for a polytetrafluoroethylene flexible stretch film. The prepared material can enable the polytetrafluoroethylene stretch film to simultaneously meet the characteristics of small pore size, uniform distribution and high mechanical strength.

[0004] The present invention adopts the following technical scheme: a preparation method of polytetrafluoroethylene flexible stretch film material, which comprises the following steps: step 1, preparing raw materials: using deionized water as a medium, ammonium perfluoropolyether carboxylate as an emulsifier, paraffin as a stabilizer, di-tert-butyl peroxide as an initiator, ferrous cyclohexaneate as a reducing agent, acrylic acid and isocyanoethyl methacrylate as modification aids, and tetrafluoroethylene as a polymerization monomer; step 2, adding deionized water, ammonium perfluoropolyether carboxylate, paraffin and acrylic acid into a polymerization kettle for evacuation and replacement treatment, and then performing polymerization reaction at a polymerization temperature of 60 to 70°C, and then adding di-tert-butyl peroxide into the polymerization kettle for stirring, and then adding tetrafluoroethylene into the polymerization kettle for evacuation and replacement treatment. Vinyl fluoride monomer is added into a polymerization kettle at a pressure of 1.8-2.5 MPa, and then half of the ferrous cyclohexaneate is dissolved in water to mix into a ferrous cyclohexaneate solution, and the ferrous cyclohexaneate solution is continuously added into the polymerization kettle for constant pressure polymerization; step three, after gradually adding all the tetrafluoroethylene into the reactor, the stirring is suspended, the gas in the reactor is depressurized to a slightly positive pressure, and the pressure after depressurization is 0.3-0.6 MPa, and nitrogen is filled in, isocyanatoethyl methacrylate and the remaining ferrous cyclohexaneate are added into the reactor for reaction, and the reaction is terminated after 1-2 hours, and after cooling, discharging, condensing, washing and drying, a polytetrafluoroethylene flexible stretch film material powder resin is obtained.

[0005] Step 4, Further, the dosage of each component in step 1 of the present invention is: based on the amount of deionized water added, when the deionized water is 100 parts, the amount of di-tert-butyl peroxide is 5.5×10 -4 parts, ferrous naphthenate is 1.1×10 -3 parts, paraffin is 5 parts, tetrafluoroethylene is 30-40 parts, acrylic acid is 0.25-0.5 parts, isocyanoethyl methacrylate is 0.5-1 parts, and perfluoropolyether carboxylic acid ammonium is 0.1-0.2 parts.

[0006] Furthermore, in step 2 of the present invention, when adding the ferrous cyclohexaneate solution, a metering pump is used to continuously add it to the polymerization kettle at a speed of 0.5 L / h to perform constant pressure polymerization.

[0007] The present invention has the following beneficial effects: after adopting the above technical scheme, the present invention adopts a dispersed resin polymerization process with deionized water as a medium, ammonium perfluoropolyether carboxylate as an emulsifier, paraffin as a stabilizer, di-tert-butyl peroxide as an initiator, ferrous cyclohexaneate as a reducing agent, acrylic acid and isocyanoethyl methacrylate as modification aids, and tetrafluoroethylene as a polymerization monomer. The method introduces a modification group to change the overall structure of the polytetrafluoroethylene stretch film, reduce the crystallinity, and make the prepared polytetrafluoroethylene stretch film softer, with good stretching performance, smaller pore size, higher porosity, and uniform pore size distribution, thereby meeting the production and application requirements of high-performance stretch films. DETAILED DESCRIPTION

[0008] The preferred embodiments of the present invention are described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0009] The invention discloses a method for preparing a material for a polytetrafluoroethylene flexible stretch film. The method comprises the following steps: step 1, preparing raw materials: using deionized water as a medium, ammonium perfluoropolyether carboxylate as an emulsifier, paraffin as a stabilizer, di-tert-butyl peroxide as an initiator, ferrous cyclohexaneate as a reducing agent, acrylic acid and isocyanoethyl methacrylate as modification aids, and tetrafluoroethylene as a polymerization monomer; step 2, adding deionized water, ammonium perfluoropolyether carboxylate, paraffin and acrylic acid into a polymerization kettle for vacuum replacement treatment, then performing a polymerization reaction at a polymerization temperature of 60 to 70° C., then adding di-tert-butyl peroxide into the polymerization kettle for stirring, then adding tetrafluoroethylene monomer into the polymerization kettle at a pressure of 1.8 to 2.5 MPa, and then adding half of the amount of The ferrous cyclohexaneate is dissolved in water to form a ferrous cyclohexaneate solution, and the ferrous cyclohexaneate solution is continuously added to the polymerization kettle for constant pressure polymerization; step three, after gradually adding all the tetrafluoroethylene into the reactor, the stirring is suspended, the gas in the reactor is depressurized to a slightly positive pressure, the pressure after depressurization is 0.3-0.6MPa, and nitrogen is filled, methacrylate isocyanatoethyl and the remaining ferrous cyclohexaneate are added to the reactor for reaction, and the reaction is terminated after 1-2 hours of reaction. After cooling, discharging, condensing, washing and drying, a polytetrafluoroethylene flexible stretch film material powder resin is obtained. The amount of each component in step one is: based on the amount of deionized water added, by weight, when the deionized water is 100 parts, the amount of di-tert-butyl peroxide is 5.5×10 -4 parts, ferrous naphthenate is 1.1×10 -3 , paraffin is 5 parts, tetrafluoroethylene is 30-40 parts, acrylic acid is 0.25-0.5 parts, isocyanoethyl methacrylate is 0.5-1 parts, and ammonium perfluoropolyether carboxylate is 0.1-0.2 parts. When adding ferrous cyclopentaneate solution in step 2, a metering pump is used to continuously add it to the polymerization kettle at a speed of 0.5L / h for constant pressure polymerization.

[0010] The present invention is further illustrated by the following examples.

[0011] Embodiment 1, the present invention discloses a preparation method of polytetrafluoroethylene flexible stretch film material, which comprises the following steps: step 1, preparing raw materials: using deionized water as a medium, ammonium perfluoropolyether carboxylate as an emulsifier, paraffin as a stabilizer, di-tert-butyl peroxide as an initiator, ferrous cyclopentaneate as a reducing agent, acrylic acid and isocyanoethyl methacrylate as modification aids, and tetrafluoroethylene as a polymerization monomer; step 2, adding 90kg of ionized water, 180g of ammonium perfluoropolyether carboxylate, 4.5kg of paraffin and 450g of acrylic acid into a 160L polymerization kettle for evacuation and replacement treatment, and then performing polymerization reaction at a polymerization temperature of 60°C, and then adding 0.5g of di-tert-butyl peroxide into the polymerization kettle for stirring, and then adding tetrafluoroethylene monomer into the polymerization kettle at a pressure of 2.5MPa, and then dissolving 0.5g of ferrous cyclopentaneate in 1L of water to mix into a ferrous cyclopentaneate solution, and continuously adding the ferrous cyclopentaneate solution into the polymerization kettle for constant pressure polymerization, When adding the ferrous cyclohexane solution, a metering pump is used to continuously add it to the polymerization kettle at a speed of 0.5L / h for constant pressure polymerization; step three, after gradually adding all 36kg of tetrafluoroethylene into the reactor, stirring is suspended, the gas in the reactor is depressurized to a slightly positive pressure, the pressure after depressurization is 0.5MPa, and 0.6MPa of nitrogen is filled in, 900g of isocyanatoethyl methacrylate and the remaining 0.5g of ferrous cyclohexane solution are added to the reactor for reaction, the reaction is terminated after 1 hour, and after cooling, discharging, condensing, washing and drying, a polytetrafluoroethylene flexible stretch film material powder resin is obtained.

[0012] Embodiment 2, the present invention discloses a method for preparing a polytetrafluoroethylene flexible stretch film material, which comprises the following steps: step 1, preparing raw materials: using deionized water as a medium, ammonium perfluoropolyether carboxylate as an emulsifier, paraffin as a stabilizer, di-tert-butyl peroxide as an initiator, ferrous cyclohexaneate as a reducing agent, acrylic acid and isocyanoethyl methacrylate as modification aids, and tetrafluoroethylene as a polymerization monomer; step 2, adding 3400kg of deionized water, 3.4kg of ammonium perfluoropolyether carboxylate, 170kg of paraffin and 8.5kg of acrylic acid into 5.5m 3The polymerization kettle was evacuated and replaced, and then the polymerization reaction was carried out at a polymerization temperature of 60°C. Then 18.5 g of di-tert-butyl peroxide was added to the polymerization kettle for stirring. Then tetrafluoroethylene monomer was added to the polymerization kettle at a pressure of 1.8 MPa. Then 18.5 g of ferrous cyclopentaneate was dissolved in 30 L of water to form a ferrous cyclopentaneate solution. The ferrous cyclopentaneate solution was continuously added to the polymerization kettle for constant pressure polymerization. When adding the ferrous cyclohexane solution, a metering pump is used to continuously add it to the polymerization kettle at a speed of 15L / h for constant pressure polymerization; step three, after gradually adding all 1020kg of tetrafluoroethylene into the reactor, stirring is suspended, the gas in the reactor is depressurized to a slightly positive pressure, the pressure after depressurization is 0.5MPa, and 0.3MPa of nitrogen is filled in, 17kg of isocyanatoethyl methacrylate and the remaining 18.5g of ferrous cyclohexane solution are added to the reactor for reaction, the reaction is terminated after 1 hour, and after cooling, discharging, condensing, washing and drying, a polytetrafluoroethylene flexible stretch film material powder resin is obtained.

[0013] Embodiment 3, the present invention discloses a method for preparing a polytetrafluoroethylene flexible stretch film material, which comprises the following steps: step 1, preparing raw materials: using deionized water as a medium, ammonium perfluoropolyether carboxylate as an emulsifier, paraffin as a stabilizer, di-tert-butyl peroxide as an initiator, ferrous cyclohexaneate as a reducing agent, acrylic acid and isocyanoethyl methacrylate as modification aids, and tetrafluoroethylene as a polymerization monomer; step 2, adding 3400kg of deionized water, 6.8kg of ammonium perfluoropolyether carboxylate, 170kg of paraffin and 17kg of acrylic acid into 5.5m 3 The polymerization kettle was evacuated and replaced, and then the polymerization reaction was carried out at a polymerization temperature of 60°C. Then 18.5 g of di-tert-butyl peroxide was added to the polymerization kettle for stirring. Then tetrafluoroethylene monomer was added to the polymerization kettle at a pressure of 2.0 MPa. Then 18.5 g of ferrous cyclopentaneate was dissolved in 30 L of water to form a ferrous cyclopentaneate solution. The ferrous cyclopentaneate solution was continuously added to the polymerization kettle for constant pressure polymerization. When adding the ferrous cyclohexane solution, a metering pump is used to continuously add it to the polymerization kettle at a speed of 15L / h for constant pressure polymerization; step three, after gradually adding all 1200kg of tetrafluoroethylene into the reactor, stirring is suspended, the gas in the reactor is depressurized to a slightly positive pressure, the pressure after depressurization is 0.5MPa, and 0.6MPa of nitrogen is filled in, 34kg of isocyanatoethyl methacrylate and the remaining 18.5g of ferrous cyclohexane solution are added to the reactor for reaction, and the reaction is terminated after 2 hours of reaction. After cooling, discharging, condensation, washing and drying, a polytetrafluoroethylene flexible stretch film material powder resin is obtained.

[0014] Without limitation to this, any changes or substitutions that are not conceived through creative work should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined in the claims.

Claims

1. A method for preparing a polytetrafluoroethylene flexible stretch film material, characterized in that It includes the following steps: Step 1, preparing raw materials: using deionized water as a medium, ammonium perfluoropolyether carboxylate as an emulsifier, paraffin as a stabilizer, di-tert-butyl peroxide as an initiator, ferrous cyclohexaneate as a reducing agent, acrylic acid and isocyanoethyl methacrylate as modification aids, and tetrafluoroethylene as a polymerization monomer; Step 2: adding ionized water, ammonium perfluoropolyether carboxylate, paraffin and acrylic acid into a polymerization kettle for evacuation and replacement treatment, then carrying out polymerization reaction at a polymerization temperature of 60 to 70° C., then adding di-tert-butyl peroxide into the polymerization kettle for stirring, then adding tetrafluoroethylene monomer into the polymerization kettle at a pressure of 1.8 to 2.5 MPa, then dissolving half of the amount of ferrous cyclopentaneate in water to form a ferrous cyclopentaneate solution, and continuously adding the ferrous cyclopentaneate solution into the polymerization kettle for constant pressure polymerization; Step three, after gradually adding all the tetrafluoroethylene into the reactor, suspend stirring, release the pressure of the gas in the reactor to a slightly positive pressure, the pressure after the pressure release is 0.3-0.6MPa, and fill with nitrogen, add isocyanoethyl methacrylate and the remaining ferrous cyclohexaneate into the reactor for reaction, terminate the reaction after 1-2 hours, and obtain the polytetrafluoroethylene flexible stretch film material powder resin after cooling, discharging, condensing, washing and drying.

2. The method for preparing the polytetrafluoroethylene flexible stretch film material according to claim 1, characterized in that The dosage of each component in step 1 is: based on the amount of deionized water added, when the deionized water is 100 parts, the amount of di-tert-butyl peroxide is 5.5×10 -4 parts, ferrous naphthenate is 1.1×10 -3 parts, paraffin is 5 parts, tetrafluoroethylene is 30-40 parts, acrylic acid is 0.25-0.5 parts, isocyanoethyl methacrylate is 0.5-1 parts, and perfluoropolyether carboxylic acid ammonium is 0.1-0.2 parts.

3. The method for preparing the polytetrafluoroethylene flexible stretch film material according to claim 1, characterized in that In step 2, when adding the ferrous cyclohexaneate solution, a metering pump is used to continuously add it to the polymerization kettle at a speed of 0.5 L / h to perform constant pressure polymerization.