CN102517794A - Method for preparing air-permeable waterproof polyurethane nanofiber membrane - Google Patents

Abstract

The invention provides a method for preparing an air-permeable and water-impermeable polyurethane nanofiber membrane, which is characterized in that it comprises: preparing a polyurethane solution with a polyurethane mass concentration of 8% to 15%, and adopting the obtained polyurethane solution into a The electrospinning device performs electrospinning to form a breathable and impermeable polyurethane nanofiber membrane with a fiber diameter of 20nm~2μm and a film thickness of 0.02mm. The polyurethane nanofiber membrane prepared by the invention not only has excellent air permeability, but also has good waterproof performance.

Description

A kind of preparation method of breathable impermeable polyurethane nanofiber film

technical field

The invention relates to a preparation method of an air-permeable and water-impermeable polyurethane nanofiber membrane, belonging to the technical field of nanomaterials.

Background technique

Due to its unique flexibility, abrasion resistance, bacteria resistance and solvent resistance, polyurethane is widely used in the coating of medium and high-grade fabrics. In recent years, with the development of polyurethane microporous coated fabrics and water-based polyurethane film fabrics, waterproof fabrics with waterproof properties have been prepared by solvent/non-solvent technology, dry coating technology, high boiling point organic droplet technology and melt extrusion molding. Breathable polyurethane films have been widely used in military, high-end clothing and medical textiles. However, in the actual production process, the above method has disadvantages such as relatively cumbersome process, low air permeability (usually 0.05cm ³ /cm ² /s), high production cost, and serious environmental pollution, and needs further improvement.

Electrospinning technology, as a simple and effective method for preparing fibers with diameters ranging from hundreds of nanometers to several microns, is developing rapidly and has attracted widespread attention from academia and industry. So far, there are hundreds of polymer fiber membranes prepared by melt and solution electrospinning technology, and because of their unique advantages, they are widely used in protective materials, high-end clothing, catalyst carriers, biological tissue engineering, dye sensitization Solar cells, ultra-high sensitivity biosensors and other fields.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a polyurethane nanofiber membrane with good air permeability and excellent waterproof performance.

In order to achieve the above object, the present invention provides a method for preparing an air-permeable and water-impermeable polyurethane nanofiber membrane, which is characterized in that it comprises: preparing a polyurethane solution with a polyurethane mass concentration of 8% to 15%, and using the obtained polyurethane solution with multiple An electrospinning device with three spinnerets was used for electrospinning to form a breathable and impermeable polyurethane nanofiber film with a fiber diameter of 20 nm-2 μm and a film thickness of 0.02 mm.

Preferably, the solvent of the polyurethane solution is N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, N-methylpyrrolidone, dichloromethane, dichloroethane, trichloro One or more mixtures of methane, chloromethane, benzene and toluene.

Preferably, the number of spinnerets in the electrospinning device is 5-10, and the speed at which the solution is fed to each spinneret is 5-12 ml/hour.

Preferably, the voltage used during the electrospinning is 15-25 kV.

Preferably, the ambient temperature during the electrospinning process is 15-35 ^o C.

Preferably, the relative humidity of the environment during the electrospinning process is 20-50%.

Preferably, the vertical distance between the spinneret and the receiving material (that is, the fiber receiving distance) is 5-15 cm.

Preferably, the receiving material is tin foil, copper mesh, fabric or non-woven fabric.

The advantages of the present invention are as follows:

(1) The polyurethane nanofiber membrane prepared by the present invention not only has excellent air permeability, but also has good waterproof performance, which overcomes the difficulty of preparing a membrane material with both air permeability and water resistance in the existing coating deposition technology. Shortcomings, can be widely used in military, high-end clothing and medical textiles, wound accessories and other fields.

(2) The air permeability and water impermeability of the polyurethane nanofiber membrane prepared by the present invention has an air permeability of 0.4 to 0.6 cm ³ /cm ² /s, and at the same time, a waterproof performance of 30 to 36 cmH ₂ O, while ordinary fabrics Almost no water resistance.

(3) The present invention can prepare a large amount of air-permeable and water-impermeable polyurethane nanofiber membranes. Taking 10 spinnerets as an example, and then electrospinning at a solution input speed of 12 mL/h, the yield of polyurethane nanofiber membranes can reach 15 g/m ² h. Compared with traditional single-nozzle electrospinning, There are dozens of times the improvement.

Detailed ways

The present invention will be described in detail below in conjunction with the examples.

Example 1

At room temperature of 23 ^o C, 4.8 g of polyurethane was added to a closed vessel containing 55.2 g of NN-dimethylacetamide, and stirred at a speed of 50 rpm on a magnetic stirrer for 12 hours until the polyurethane was completely dissolved and the solution was free. Color transparent liquid, obtains the polyurethane solution that mass fraction is 8%.

Under the conditions of room temperature 15 ^o C and relative humidity of 20%, 5 spinnerets were used for spinning, each spinneret delivered polyurethane solution at a speed of 5 mL/h, and 5 spinnerets were connected to a high voltage of 15 kV at the same time. Electrostatic generator, aluminum foil is used to receive fibers, the fiber receiving distance is 5 cm, and a polyurethane nanofiber film with air-permeable and impervious properties is obtained, the fiber film thickness is 0.02 mm, the yield is 3 g/m ² h up to 0.42 cm ³ /cm ² ·s. Under the same concentration conditions, the polyurethane film prepared by the existing coating deposition method has an air permeability of 0.051 cm ³ /cm ² ·s. Meanwhile, the waterproof performance of the polyurethane fiber membrane obtained in this example is 30 cmH ₂ O.

Example 2

At room temperature of 23 ^o C, 6 g of polyurethane was added to a closed vessel containing 54 g of NN-dimethylformamide, and stirred vigorously on a magnetic stirrer at a speed of 100 rpm for 12 hours until the polyurethane was completely dissolved and the solution was Colorless transparent liquid, the polyurethane solution that obtains mass fraction is 10%.

At a room temperature of 25 ^o C and a relative humidity of 20%, 5 spinnerets were used for spinning, and the speed of each spinneret delivering polyurethane solution was 5 mL/h. At the same time, 5 spinnerets were connected to a 20 kV A high-voltage electrostatic generator, using a copper mesh to receive fibers, the fiber receiving distance is 15 cm, and a polyurethane nanofiber film with air-permeable and impermeable properties is obtained, the fiber film thickness is 0.02 mm, and the yield is 4 g/m ² h, which is breathable The performance index reaches 0.57 cm ³ /cm ² ·s. Under the same concentration conditions, the air permeability of the polyurethane film prepared by the existing coating deposition method is 0.048 cm ³ /cm ² ·s. At the same time, the waterproof performance of the polyurethane fiber membrane obtained in this example was increased to 36.5 cmH ₂ O.

Example 3

At room temperature of 23 ^o C, 9.6 g of polyurethane was added to a closed container filled with 86.4 g of tetrahydrofuran, and vigorously stirred at a speed of 100 rpm on a magnetic stirrer for 12 hours until the polyurethane was completely dissolved and the solution was a colorless transparent liquid. The mass fraction is 10% polyurethane solution.

Under the conditions of room temperature 35 ^o C and relative humidity of 30%, 8 spinnerets were used for spinning, each spinneret delivered polyurethane solution at a rate of 6 mL/h, and 8 spinnerets were connected to a high voltage of 25 kV at the same time. Electrostatic generator, using copper mesh to receive fibers, the fiber receiving distance is 10 cm, and the polyurethane nanofiber membrane with air-permeable and impermeable properties can be obtained, the fiber film thickness is 0.02 mm, the yield is 5 g/m ² h, and the air-permeable performance The index reaches 0.51 cm ³ /cm ² ·s, and the waterproof performance reaches 35 cmH ₂ O. Under the same concentration conditions, the polyurethane film prepared by the existing coating deposition method has an air permeability of 0.046 cm ³ /cm ² ·s.

Example 4

Under the condition of room temperature of 23 ^o C, 14.4 g of polyurethane was added to a closed vessel containing 81.6 g of NN-dimethylformamide, and stirred vigorously at a speed of 200 rpm on a magnetic stirrer for 12 hours until the polyurethane was completely dissolved , the solution was a colorless transparent liquid, and a polyurethane solution with a mass fraction of 15% was obtained.

At a room temperature of 25 ^o C and a relative humidity of 40%, 8 spinnerets were used for spinning, and each spinneret delivered polyurethane solution at a rate of 8 mL/h. At the same time, 8 spinnerets were connected to a high voltage of 25 kV. Electrostatic generator, use fabric or non-woven fabric to receive fibers, the fiber receiving distance is 10 cm, and obtain polyurethane nanofiber membrane with breathable and impermeable properties, the fiber membrane thickness is 0.02 mm, and the yield is 9.6 g/m ² h, The gas permeability index reaches 0.55 cm ³ /cm ² ·s, and the waterproof performance is 32 cmH ₂ O. Under the same concentration conditions, the air permeability of the polyurethane film prepared by the existing coating deposition method is 0.04 cm ³ /cm ² ·s.

Example 5

At room temperature of 23 ^o C, add 18 g of polyurethane to a closed container containing 102 g of tetrahydrofuran/NN-dimethylformamide (weight ratio 1/3) solution, and stir vigorously at a speed of 100 rpm on a magnetic stirrer 12 hours, until the polyurethane dissolves completely, the solution is light yellow transparent liquid, and the polyurethane solution that obtains mass fraction is 15%.

At a room temperature of 35 ^o C and a relative humidity of 50%, 10 spinnerets were used for spinning, each spinneret transported polyurethane solution at a rate of 10 mL/h, and 10 spinnerets were connected to a high voltage of 25 kV at the same time. Electrostatic generator, using copper mesh to receive fibers, the fiber receiving distance is 15 cm, that is, a polyurethane nanofiber film with air-permeable and impermeable properties is obtained, the fiber film thickness is 0.02 mm, the yield is 15 g/m ² h, and the air-permeable performance index Up to 0.50 cm ³ /cm ² ·s, waterproof performance up to 34.5 cmH ₂ O. Under the same concentration conditions, the air permeability of the polyurethane film prepared by the existing coating deposition method is 0.04 cm ³ /cm ² ·s.

Example 6

At room temperature 23 ^o C, 9.6 g of polyurethane was added to a closed container containing 110.4 g of tetrahydrofuran/NN-dimethylacetamide (weight ratio 1/3) solution, and stirred vigorously at a speed of 50 rpm on a magnetic stirrer 12 hours, until polyurethane dissolves completely, solution is colorless transparent liquid, obtains the polyurethane solution that mass fraction is 8%.

At a room temperature of 35 ^o C and a relative humidity of 50%, 10 spinnerets were used for spinning, each spinneret transported polyurethane solution at a rate of 10 mL/h, and 10 spinnerets were connected to a high voltage of 20 kV at the same time. Electrostatic generator, using copper mesh to receive fibers, the fiber receiving distance is 12 cm, that is, a polyurethane nanofiber film with air-permeable and impermeable properties is obtained, the fiber film thickness is 0.02 mm, the yield is 8 g/m ² h, and the air-permeable performance index Up to 0.56 cm ³ /cm ² ·s, waterproof up to 36 cmH ₂ O. Under the same concentration conditions, the polyurethane film prepared by the existing coating deposition method has an air permeability of 0.051 cm ³ /cm ² ·s.

In the process of solution preparation and electrospinning, the mass fraction of polyurethane solution and electrospinning parameters were changed, and the yield of polyurethane fiber membrane was improved in different degrees. Compared with the existing methods for preparing polyurethane membranes by coating deposition, the polyurethane fiber membranes prepared by electrospinning are more excellent in air permeability and impermeability.

Claims (8)

1. the preparation method of a permeable watertight polyurethane nanofiber film; It is characterized in that; Comprise: preparation polyurethane mass concentration is 8% ~ 15% polyurethane solutions; Adopt the electrostatic spinning apparatus with a plurality of spinning heads to carry out electrostatic spinning the polyurethane solutions of gained, the formation fibre diameter is that 20nm ~ 2 μ m, thickness are the permeable watertight polyurethane nanofiber film of 0.02 mm.

2. the preparation method of permeable watertight polyurethane nanofiber film as claimed in claim 1 is characterized in that, the solvent of described polyurethane solutions is N, dinethylformamide; DMAC N,N, oxolane; N-Methyl pyrrolidone, carrene, dichloroethanes; Chloroform, monochloro methane, a kind of or mixture more than two kinds in benzene and the toluene.

3. the preparation method of permeable watertight polyurethane nanofiber film as claimed in claim 1 is characterized in that, the spinning head quantity of described electrostatic spinning apparatus is 5 ~ 10, solution the speed on each spinning head of being input to be the 5-12 milliliter/hour.

4. the preparation method of permeable watertight polyurethane nanofiber film as claimed in claim 1 is characterized in that, used voltage is 15-25 kV during described electrostatic spinning.

5. the preparation method of permeable watertight polyurethane nanofiber film as claimed in claim 1 is characterized in that, environment temperature is 15-35 in the described electrostatic spinning process ^oC.

6. the preparation method of permeable watertight polyurethane nanofiber film as claimed in claim 1 is characterized in that, envionmental humidity is 20-50% in the described electrostatic spinning process.

7. the preparation method of permeable watertight polyurethane nanofiber film as claimed in claim 1 is characterized in that, described spinning head and the vertical interval that receives between the material are 5-15 cm.

8. the preparation method of permeable watertight polyurethane nanofiber film as claimed in claim 1 is characterized in that, described reception material is tinfoil, copper mesh, fabric or nonwoven fabric.