Preparation Method of a Crosslinked Modified Glass Fiber Composite Veneer Material of Polyvinylidene Fluoride / Polyurethane

Abstract

The present invention provides a preparation method of a polyvinylidene fluoride / polyurethane crosslinked modified glass fiber composite veneer material, which includes the activation treatment of the glass fiber veneer material, the preparation of the nanofiber membrane, and the crosslinking modification. The method for the activation treatment of the glass fiber veneer material is to impregnate the semi-finished glass fiber veneer with a hydrochloric acid solution for 2 - 3 h, and then obtain the activated glass fiber veneer material through washing and drying. The method for the preparation of the nanofiber membrane is to prepare a nanofiber membrane containing polyvinylidene fluoride, diphenylmethane diisocyanate, and titanium oxide on the surface of the activated glass fiber veneer material by electrospinning. For the crosslinking modification, diphenylmethane diisocyanate in the nanofiber membrane reacts with the hydroxyl groups on the surface of the activated glass fiber veneer material to generate polyurethane. The composite veneer material prepared by the present invention realizes the coordinated regulation of water impermeability and water vapor transmission rate, and has high wear resistance and tensile elasticity.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and relates to a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite facing material and a preparation method thereof. Background Art

[0002] In the construction field, water and water vapor are important factors threatening building safety. The traditional waterproof system is to cover an airtight waterproof layer outside the insulation layer to prevent external rainwater from penetrating. Although this method blocks rainwater outside the building, it also "blocks" the water vapor from indoors in the insulation layer, making it unable to be effectively discharged, resulting in the insulation layer getting damp and thus damaging its heat preservation and durability. To solve the contradiction between waterproofing needs and breathability needs, with the increasingly strict requirements for preventing indoor water vapor and the improvement of waterproof technology, a new type of polymer membrane that combines waterproofing and breathability functions - waterproof and breathable membrane has gradually attracted people's attention.

[0003] The waterproof and breathable membrane is applied to pitched roofs, steel structure roofs, and building facades. By covering the waterproof and breathable membrane outside the insulation layer, its excellent water vapor permeability and waterproofness can not only prevent external rainwater from invading and water vapor from condensing and re-infiltrating into the insulation layer, but also discharge the moisture in the insulation layer, keeping the insulation layer dry all the time and maintaining the heat preservation effect, thereby ensuring the long-term effectiveness of the insulation layer and the building structure.

[0004] Building waterproof and breathable membranes are generally divided into two types according to the vapor permeation principle: polytetrafluoroethylene (PTFE) microporous membranes and thermoplastic polyurethane (TPU) hydrophilic non-porous membranes. The TPU non-porous membrane has a high hydrostatic pressure resistance due to its non-porous structure, but this material has problems such as poor moisture permeability and easy wetting when encountering water.

[0005] At present, most building waterproof and breathable membranes are microporous membranes. The micropore diameter determines the balance of the two properties of waterproofing and breathability of the membrane material. If the pore diameter is too large, the water vapor transmission rate increases and the water impermeability decreases accordingly; vice versa. Microporous membranes are mainly made by mixing, thermoforming, and stretching processes of raw materials such as polymers, fillers, and additives. When stretching, interconnected micropores or channels with a diameter of about 1 μm are formed around, and the waterproof and moisture-permeable effect can be achieved through the sieving effect (the minimum diameter of water droplets is about 20 μm, and the diameter of water vapor is only 0.0004 μm). However, the existing microporous membranes have a decrease in moisture permeability due to the reduction and deformation of micropores during use due to their thermoplastic properties; the mechanical properties of the existing microporous membranes are not good, and the membrane surface is easily damaged, resulting in a decrease in the barrier performance.

[0006] In addition, the humid and dark living environments such as family bathrooms and kitchens have become the hardest-hit areas for the growth of mold and bacteria. The mold volatilizes into the air, forming aerosols that can be inhaled by people and cause diseases. Developing highly active antibacterial and mildew-proof products has become a trend. Products with antibacterial and mildew-proof functions can not only improve the living environment, reduce the risk of cross-contamination, but also extend the service life of building materials products. At present, the building materials products on the market mainly add antibacterial agents in the form of coatings to achieve antibacterial and mildew-proof effects, but there is a problem of antibacterial agent loss, resulting in the problem that the antibacterial property of building membrane materials is not durable.

[0007] At present, the method of hot melt adhesive lamination is generally used to laminate the building waterproof and breathable membrane with the substrate. However, after lamination, the micropores of the middle breathable membrane are easily blocked by the hot melt adhesive, resulting in a decrease in the water vapor transmission rate. And the hot melt adhesive has poor heat resistance, thus affecting the actual use of the building waterproof and breathable membrane. Summary of the Invention

[0008] Aiming at the deficiencies of the existing technology, the present invention provides a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material and its preparation method, achieving the following invention purposes: in the process of laminating the waterproof and breathable membrane with the substrate, hot melt adhesive lamination is not used; at the same time, the mechanical properties of the waterproof and breathable membrane are improved, the bonding fastness between the waterproof and breathable membrane and the substrate is improved, and thus the bursting strength and tensile elasticity of the composite veneer material are improved; at the same time, the water impermeability and water vapor transmission rate are improved; and it has antibacterial properties.

[0009] To solve the above technical problems, the present invention adopts the following technical solutions:

[0010] A preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material, comprising the following steps:

[0011] (1) Activation treatment of the glass fiber veneer material

[0012] The glass fiber cloth coated with the adhesive is laminated with kraft paper and sent into a laminating machine, and is pressed at a temperature of 148 - 152 °C and a pressure of 0.8 - 1.2 MPa for 11.5 - 12.5 h to obtain a semi-finished glass fiber veneer. Then it is immersed in a 9 - 11% (v / v) hydrochloric acid solution and impregnated at room temperature for 2 - 3 h; then it is washed two to three times by shaking with absolute ethanol and deionized water in turn, the surface is dried with dry nitrogen, and after drying at room temperature, it is dried in a blast drying oven at 105 °C for 2 h to remove the excess impurities on the surface and generate more silanol groups (Si-OH) on the glass fiber veneer for the subsequent cross-linking reaction with diphenylmethane diisocyanate, thus preparing a glass fiber veneer material with a clean surface and rich in silanol groups, that is, the activated glass fiber veneer material.

[0013] The glass fiber cloth is a plain weave non-alkali cloth with a thickness of 4.5 - 5.5 mm;

[0014] The grammage of the kraft paper is 98 - 102 g / m 2 , and the thickness is 0.14 - 0.16 mm;

[0015] The lamination is to laminate one side of the glass fiber cloth coated with the adhesive and the kraft paper;

[0016] The adhesive is an organosilicon-modified acrylate pressure-sensitive adhesive, model PYS2, provided by Zhejiang Jinjia Technology Co., Ltd.;

[0017] The coating thickness of the adhesive after curing on the glass fiber cloth is 18 ± 4 μm.

[0018] (2) Preparation of electrospinning solution and electrospraying solution

[0019] Mix polyvinylidene fluoride (PVDF) and diphenylmethane diisocyanate (MDI), then dissolve them in N-N dimethylformamide (DMF) solvent, and stir to obtain a uniform PVDF / MDI electrospinning solution. Among them, PVDF accounts for 10 - 25 wt% of the whole spinning solution, and MDI accounts for 1 - 10 wt% of the whole spinning solution;

[0020] Use titanium dioxide (TiO2) as an antibacterial agent, disperse it in DMF, and ultrasonicate it for 1 hour to prepare a TiO2 electrospraying solution, in which the mass content of titanium dioxide is 1 - 10 wt%.

[0021] (3) Preparation of nanofiber membrane

[0022] Take the activated glass fiber facing material prepared in step (1) as the receiving substrate, take an appropriate amount of PVDF / MDI electrospinning solution and TiO2 electrospraying solution and inject them into an electrospinning machine (the electrospinning machine includes 5 spinnerets), and use the "side-by-side" electrospinning method to prepare a layer of nanofiber membrane on the surface of the activated glass fiber facing material. The nanofiber membrane includes the polymer PVDF / MDI and TiO2, and the thickness of the fiber membrane is 10 - 50 μm;

[0023] Among them, the PVDF / MDI electrospinning solution deposits the polymer PVDF / MDI in the form of nanofibers on the substrate through the spinneret A, and the TiO2 electrospraying solution deposits TiO2 inorganic particles on the surface of the substrate in the form of electrostatic spraying through the spinneret B. The spinning speed of the PVDF / MDI electrospinning solution is 4 - 9 mL / h; the spraying speed of the TiO2 electrospraying solution is 1 - 20 mL / h; specifically, the ratio of the number of spinnerets of A and B is set to 1 - 4:1 - 4; preferably 4:1, 3:2, 2:3, 1:4, and the flow rate of each spinneret is 1 - 5 mL / h; the distance between the spinneret and the receiving substrate is 20 - 30 cm; the spinning time is 1 - 6 h.

[0024] (4)Crosslinking modification of MDI with the silanol groups of glass fiber

[0025] The spun nanofiber membrane and the activated glass fiber facing material are heat-treated to obtain a modified glass fiber composite facing material. The diphenylmethane diisocyanate in the nanofiber membrane crosslinks with the hydroxyl groups on the surface of the activated glass fiber facing material to generate polyurethane, and bridges are formed between the fiber membrane layer and the substrate through the urethane structure, improving the mechanical properties of the composite facing material. Among them, the heat treatment temperature is 100 - 150 °C and the time is 10 - 180 min.

[0026] On the basis of the above technical solutions, the following process parameters are optimized:

[0027] In step (2), for the PVDF / MDI electrospinning solution, PVDF accounts for 14.5 - 15.5 wt% of the entire electrospinning solution, and MDI accounts for 4.5 - 5.5 wt% of the entire electrospinning solution; for the TiO2 electrospraying solution, the mass content of titanium oxide is 4.5 - 5.5 wt%.

[0028] In step (3), the thickness of the fiber membrane is 24.8 - 25.2 μm; the receiving distance is 24.5 - 25.5 cm, the spinning speed of the PVDF / MDI electrospinning solution is 5.5 - 6.5 mL / h; the spraying speed of the TiO2 electrospraying solution is 3.5 - 4.5 mL / h.

[0029] In step (4), the heat treatment temperature is 118 - 122 °C and the time is 85 - 95 min.

[0030] The technical effects achieved by the above preferred technical solutions are as follows: For the polyvinylidene fluoride / polyurethane crosslinked and modified glass fiber composite facing material prepared by the present invention, the diameter of the fibers in the surface fiber membrane is 375 - 380 nm, the pore size of the fiber membrane is 1.24 - 1.28 μm, and the porosity of the fiber membrane is 67.4 - 68.2%; the water impermeability (2 h) is 1950 - 2000 mm; the water vapor transmission rate is 3000 - 3200 g / m2 / d; the antibacterial rate against Staphylococcus aureus is 78 - 82%, and the antibacterial rate against Escherichia coli is 79 - 83%; the bursting strength is 88 - 90 N; the longitudinal tensile breaking strength is 153 - 155 N / 25 mm; the transverse tensile breaking strength is 95 - 97 N / 25 mm.

[0031] The present invention utilizes the condensation of the -NCO group at the end of the MDI oligomer with the hydroxyl groups on the surface of the activated glass fiber facing material to achieve in-situ crosslinking to generate a polyurethane structure. While further improving the mechanical properties of the fiber membrane, it also improves the bonding strength between the fiber membrane and the glass fiber substrate, overall enhancing the bursting strength and tensile elasticity of the composite building facing material, effectively improving the service life of the composite facing material; at the same time, a waterproof and breathable membrane with antibacterial properties is prepared by the side-by-side electrospinning method in one step, realizing the coordinated regulation of two indicators of water vapor permeability and water impermeability of the building waterproof and breathable membrane, and having good antibacterial properties.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite facing material prepared by the present invention by combining electrospinning and heat treatment method forms a rich micro-nano multi-level pore structure between the nanofiber membrane and the glass fiber substrate, realizing the coordination of the small pore diameter and high porosity of the fiber membrane, and realizing the coordinated regulation of two indicators of water vapor permeability and water impermeability of the building waterproof and breathable membrane. While effectively avoiding the erosion of the moisture in the external environment on the facing material, it can also ensure the exudation of the moisture contained in building materials such as cement in the wall, extend the service life of the facing material, and improve the versatility of the facing material. For the polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite facing material prepared by the present invention, the diameter of the fibers in the surface fiber membrane is 315 - 740 nm, the pore diameter of the fiber membrane is 1.04 - 1.65 μm, and the porosity of the fiber membrane is 52.3 - 82.3%;

[0034] According to the test standards of GB / T328.10 "Bitumen and polymer waterproofing membranes" and GB / T1037 "Test method for water vapor transmission of plastic films and sheets - Cup method", the water impermeability (2 h) is 1000 - 2000 mm; the water vapor transmission rate is 1000 - 3200 g / m 2 / d.

[0035] (2) The polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material prepared by the present invention uses the side-by-side electrospinning method to form a waterproof and breathable film with antibacterial properties in one step. Titanium oxide is distributed on the surface and interface of the nanofiber membrane in the form of electrospraying, providing good antibacterial properties and avoiding the problem of damaging its original properties by using the method of adding antibacterial agents by coating. According to JIS Z 2801:2010 Antibacterial processed products - Antibacterial test method - Antibacterial effect, its antibacterial properties are tested. The antibacterial rate against Staphylococcus aureus is 73 - 99%, and the antibacterial rate against Escherichia coli is 75 - 95%.

[0036] (3) For the polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material of the present invention, the mechanical properties of the composite veneer material are determined according to the standard of JC / T 2028-2018 Composite veneer material for mineral wool thermal insulation products. The bursting strength is 80 - 98 N; the longitudinal tensile breaking strength is 150 - 160 N / 25 mm; the transverse tensile breaking strength is 90 - 100 N / 25 mm. The cross-linking reaction between MDI in the fiber membrane and the hydroxyl groups on the surface of the glass fiber generates polyurethane, and bridges are formed between the fiber membrane layer and the substrate through the urethane structure. While further improving the mechanical properties of the fiber membrane, it also improves the bonding fastness between the fiber membrane and the glass fiber substrate. The overall composite building veneer material has high wear resistance and tensile elasticity, effectively improving the service life of the veneer material provided by the present invention. Specific embodiments

[0037] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0038] Example 1 A preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material

[0039] It includes the following steps:

[0040] (1) Activation treatment of the glass fiber veneer material

[0041] The glass fiber cloth coated with adhesive is laminated with kraft paper and fed into a laminating and compounding machine. It is pressed for 12 hours under the conditions of a temperature of 150 °C and a pressure of 1 MPa to obtain a semi-finished glass fiber veneer. It is immersed in a 10% (v / v) hydrochloric acid solution and impregnated at room temperature for 2 hours. Then, it is washed two to three times by shaking with anhydrous ethanol and deionized water in sequence, dried with dry nitrogen on the surface, air-dried at room temperature, and then dried in a forced-air drying oven at 105 °C for 2 hours to remove the excess impurities on the surface and generate more silanol groups (Si-OH) on the glass fiber veneer for the subsequent cross-linking reaction with diphenylmethane diisocyanate, thereby preparing a glass fiber veneer material with a clean surface and rich in silanol groups, that is, the activated glass fiber veneer material.

[0042] The glass fiber cloth is a plain weave alkali-free cloth with a thickness of 5 mm;

[0043] The grammage of the kraft paper is 100 g / m 2 , and the thickness is 0.15 mm;

[0044] The lamination is to laminate one side of the glass fiber cloth coated with adhesive with the kraft paper;

[0045] The adhesive is an organosilicon-modified acrylate pressure-sensitive adhesive, model PYS2, provided by Zhejiang Jinjia Technology Co., Ltd.;

[0046] The coating thickness of the adhesive after curing on the glass fiber cloth is 14 μm.

[0047] (2) Preparation of electrospinning solution and electrospraying solution

[0048] Polyvinylidene fluoride (PVDF) and diphenylmethane diisocyanate (MDI) are mixed and then dissolved in N-N dimethylformamide (DMF) solvent. After stirring, a uniform PVDF / MDI electrospinning solution is obtained, in which PVDF accounts for 10 wt% of the whole spinning solution and MDI accounts for 1 wt% of the whole spinning solution;

[0049] Taking titanium dioxide (TiO2) as an antibacterial agent, it is dispersed in DMF and ultrasonicated for 1 hour to prepare a TiO2 electrospraying solution, in which the mass content of titanium dioxide is 1 wt%.

[0050] (3) Preparation of nanofiber membrane

[0051] Using the activated fiberglass facing material obtained in step (1) as the receiving substrate, an appropriate amount of PVDF / MDI electrospinning solution and TiO2 electrospray solution are injected into an electrospinning machine (the electrospinning machine includes 5 spinnerets). Using the "side-by-side" electrospinning method, a nanofiber membrane is prepared on the surface of the activated fiberglass facing material. The nanofiber membrane includes the polymer PVDF / MDI and TiO2, and the thickness of the fiber membrane is 25 μm;

[0052] Among them, the PVDF / MDI electrospinning solution deposits the polymer PVDF / MDI on the substrate in the form of nanofibers through spinneret A, and the TiO2 electrospray solution deposits TiO2 inorganic particles on the surface of the substrate in the form of electrospray through spinneret B. Specifically, the ratio of the number of spinnerets of A and B is set to 4:1, and the flow rate of each spinneret is 1 mL / h; the distance between the spinneret and the receiving substrate is 20 cm; the spinning time is 6 h.

[0053] (4)Crosslinking modification of MDI with silanol groups on glass fiber

[0054] The spun nanofiber membrane is heat-treated to obtain a modified fiberglass composite facing material; diphenylmethane diisocyanate in the nanofiber membrane crosslinks with the hydroxyl groups on the surface of the activated fiberglass facing material to generate polyurethane, and bridges are formed between the fiber membrane layer and the substrate through urethane structures, improving the mechanical properties of the composite facing material. Among them, the heat treatment temperature is 100 °C and the time is 180 min.

[0055] Example 2 A preparation method of a polyvinylidene fluoride / polyurethane crosslinked modified fiberglass composite facing material

[0056] It includes the following steps:

[0057] (1)Activation treatment of fiberglass facing material

[0058] The glass fiber cloth coated with adhesive is laminated with kraft paper and sent into a laminating machine. It is pressed at a temperature of 150 °C and a pressure of 1 MPa for 12 h to obtain a semi-finished fiberglass facing product. It is immersed in a 10% (v / v) hydrochloric acid solution and impregnated at room temperature for 2 h; then it is washed two to three times by shaking with absolute ethanol and deionized water in turn, dried with dry nitrogen on the surface, air-dried at room temperature and then dried in a blast drying oven at 105 °C for 2 h to remove excess impurities on the surface and generate more silanol groups (Si-OH) on the fiberglass facing to provide for the later crosslinking reaction with diphenylmethane diisocyanate, and a fiberglass facing material with a clean surface and rich in silanol groups, that is, the activated fiberglass facing material, is prepared.

[0059] The glass fiber cloth is a plain weave non-alkali cloth with a thickness of 5 mm;

[0060] The grammage of the kraft paper is 100 g / m 2 , and the thickness is 0.15 mm;

[0061] The lamination is to laminate one side of the glass fiber cloth coated with the adhesive and the kraft paper;

[0062] The adhesive is an organosilicon-modified acrylate pressure-sensitive adhesive, model PYS2, provided by Zhejiang Jinjia Technology Co., Ltd.;

[0063] The coating thickness of the adhesive after curing on the glass fiber cloth is 16 μm.

[0064] (2) Preparation of electrospinning solution and electrospray solution

[0065] Mix polyvinylidene fluoride (PVDF) and diphenylmethane diisocyanate (MDI), and then dissolve them in N-N dimethylformamide (DMF) solvent. After stirring, a uniform PVDF / MDI electrospinning solution is obtained, where PVDF accounts for 12 wt% of the whole spinning solution and MDI accounts for 2 wt% of the whole spinning solution;

[0066] Use titanium dioxide (TiO2) as an antibacterial agent, disperse it in DMF, and ultrasonically treat it for 1 hour to prepare a TiO2 electrospray solution, where the mass content of titanium dioxide is 3 wt%.

[0067] (3) Preparation of nanofiber membrane

[0068] Take the activated glass fiber facing material prepared in step (1) as the receiving substrate. Take an appropriate amount of PVDF / MDI electrospinning solution and TiO2 electrospray solution and inject them into an electrospinning machine (the electrospinning machine includes 5 spinnerets). Using the "side-by-side" electrospinning method, prepare a layer of nanofiber membrane on the surface of the activated glass fiber facing material. The nanofiber membrane includes the polymer PVDF / MDI and TiO2, and the thickness of the fiber membrane is 25 μm;

[0069] Among them, the PVDF / MDI electrospinning solution deposits the polymer PVDF / MDI in the form of nanofibers on the substrate through spinneret A, and the TiO2 electrospray solution deposits TiO2 inorganic particles on the substrate surface in the form of electrospray through spinneret B. Specifically, the ratio of the number of spinnerets of A and B is 4:1, and the flow rate of each spinneret is 2 mL / h; the distance between the spinneret and the receiving substrate is 23 cm; the spinning time is 5.5 h.

[0070] (4) Crosslinking modification of MDI and glass fiber silanol groups

[0071] The spun nanofiber membrane is heat-treated to obtain a modified glass fiber composite facing material; diphenylmethane diisocyanate in the nanofiber membrane cross-links and modifies with the hydroxyl groups on the surface of the activated glass fiber facing material to generate polyurethane, and bridges between the fiber membrane layer and the substrate through the urethane structure, improving the mechanical properties of the composite facing material. Among them, the heat treatment temperature is 110 °C and the time is 120 min.

[0072] Example 3 A preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite facing material

[0073] It includes the following steps:

[0074] (1) Activation treatment of the glass fiber facing material

[0075] The glass fiber cloth coated with the adhesive is laminated with kraft paper and sent into a laminating composite machine, and a semi-finished glass fiber facing product is prepared by pressing at a temperature of 150 °C and a pressure of 1 MPa for 12 h. It is immersed in a 10% (v / v) hydrochloric acid solution and impregnated at room temperature for 3 h; then it is washed two to three times by shaking with absolute ethanol and deionized water in turn, the surface is dried with dry nitrogen, and dried at room temperature and then dried in a blast drying oven at 105 °C for 2 h to remove excess impurities on the surface and generate more silanol groups (Si-OH) on the glass fiber facing to supply the cross-linking reaction with diphenylmethane diisocyanate later, and a glass fiber facing material with a clean surface and rich in silanol groups, that is, the activated glass fiber facing material, is prepared.

[0076] The glass fiber cloth is a plain weave alkali-free cloth with a thickness of 5 mm;

[0077] The grammage of the kraft paper is 100 g / m 2 , and the thickness is 0.15 mm;

[0078] The lamination is to laminate one side of the glass fiber cloth coated with the adhesive with the kraft paper;

[0079] The adhesive is an organosilicon-modified acrylate pressure-sensitive adhesive, model PYS2, provided by Zhejiang Jinjia Technology Co., Ltd.;

[0080] The coating thickness of the adhesive after curing on the glass fiber cloth is 18 μm.

[0081] (2) Preparation of the electrospinning solution and the electrospraying solution

[0082] Mix polyvinylidene fluoride (PVDF) and diphenylmethane diisocyanate (MDI), and then dissolve them in N,N-dimethylformamide (DMF) solvent. After stirring, a uniform PVDF / MDI electrospinning solution is obtained. Among them, PVDF accounts for 15wt% of the entire spinning solution, and MDI accounts for 5wt% of the entire spinning solution.

[0083] Use titanium dioxide (TiO2) as an antibacterial agent, disperse it in DMF, and ultrasonically treat it for 1 hour to prepare a TiO2 electrospray solution, where the mass content of titanium dioxide is 5wt%.

[0084] (3) Preparation of nanofiber membrane

[0085] Use the activated glass fiber facing material prepared in step (1) as the receiving substrate. Take an appropriate amount of PVDF / MDI electrospinning solution and TiO2 electrospray solution and inject them into an electrospinning machine (the electrospinning machine includes 5 spinnerets). Using the "side-by-side" electrospinning method, a nanofiber membrane is prepared on the surface of the activated glass fiber facing material. The nanofiber membrane includes the polymer PVDF / MDI and TiO2, and the thickness of the fiber membrane is 25μm.

[0086] Among them, the PVDF / MDI electrospinning solution deposits the polymer PVDF / MDI on the substrate in the form of nanofibers through spinneret A, and the TiO2 electrospray solution deposits TiO2 inorganic particles on the substrate surface in the form of electrospray through spinneret B. Specifically, the ratio of the number of spinnerets of A and B is 3:2, and the flow rate of each spinneret is 2mL / h; the distance between the spinneret and the receiving substrate is 25cm; the spinning time is 4h.

[0087] (4) Crosslinking modification of MDI with silanol groups on glass fiber

[0088] Heat-treat the spun nanofiber membrane to obtain a modified glass fiber composite facing material; the diphenylmethane diisocyanate in the nanofiber membrane crosslinks with the hydroxyl groups on the surface of the activated glass fiber facing material to form polyurethane, and bridges are formed between the fiber membrane layer and the substrate through the urethane structure, improving the mechanical properties of the composite facing material. Among them, the heat treatment temperature is 120°C and the time is 90min.

[0089] Example 4 A preparation method of a polyvinylidene fluoride / polyurethane crosslinked modified glass fiber composite facing material

[0090] It includes the following steps:

[0091] (1) Activation treatment of glass fiber facing material

[0092] The glass fiber cloth coated with adhesive is laminated with kraft paper and fed into a laminating and compounding machine. It is pressed for 12 hours under the conditions of a temperature of 150 °C and a pressure of 1 MPa to obtain a semi-finished glass fiber veneer. It is immersed in a 10% (v / v) hydrochloric acid solution and impregnated at room temperature for 3 hours. Then, it is washed two to three times by shaking with absolute ethanol and deionized water, dried with dry nitrogen gas on the surface, air-dried at room temperature, and then dried in a forced-air drying oven at 105 °C for 2 hours to remove excess impurities on the surface and generate more silanol groups (Si-OH) on the glass fiber veneer for the subsequent cross-linking reaction with diphenylmethane diisocyanate, thereby preparing a glass fiber veneer material with a clean surface and rich in silanol groups, that is, the activated glass fiber veneer material.

[0093] The glass fiber cloth is a plain weave alkali-free cloth with a thickness of 5 mm;

[0094] The grammage of the kraft paper is 100 g / m 2 , and the thickness is 0.15 mm;

[0095] The lamination is to laminate one side of the glass fiber cloth coated with adhesive with the kraft paper;

[0096] The adhesive is an organosilicon-modified acrylate pressure-sensitive adhesive, model PYS2, provided by Zhejiang Jinjia Technology Co., Ltd.;

[0097] The coating thickness of the adhesive after curing on the glass fiber cloth is 18 μm.

[0098] (2) Preparation of electrospinning solution and electrospraying solution

[0099] Polyvinylidene fluoride (PVDF) and diphenylmethane diisocyanate (MDI) are mixed and then dissolved in N-N dimethylformamide (DMF) solvent. After stirring, a uniform PVDF / MDI electrospinning solution is obtained, in which PVDF accounts for 18 wt% of the entire spinning solution and MDI accounts for 7 wt% of the entire spinning solution;

[0100] Taking titanium dioxide (TiO2) as an antibacterial agent, it is dispersed in DMF and ultrasonicated for 1 hour to prepare a TiO2 electrospraying solution, in which the mass content of titanium dioxide is 7 wt%.

[0101] (3) Preparation of nanofiber membrane

[0102] Using the activated fiberglass facing material obtained in step (1) as the receiving substrate, an appropriate amount of PVDF / MDI electrospinning solution and TiO2 electrospray solution are injected into an electrospinning machine (the electrospinning machine includes 5 spinnerets). Using the "side-by-side" electrospinning method, a nanofiber membrane is prepared on the surface of the activated fiberglass facing material. The nanofiber membrane includes the polymer PVDF / MDI and TiO2, and the thickness of the fiber membrane is 25 μm;

[0103] Among them, the PVDF / MDI electrospinning solution deposits the polymer PVDF / MDI on the substrate in the form of nanofibers through spinneret A, and the TiO2 electrospray solution deposits TiO2 inorganic particles on the surface of the substrate in the form of electrospray through spinneret B. Specifically, the ratio of the number of spinnerets of A and B is set to 3:2, and the flow rate of each spinneret is 3 mL / h; the distance between the spinneret and the receiving substrate is 27 cm; the spinning time is 3.5 h.

[0104] (4)Crosslinking modification of MDI with the silanol groups of glass fiber

[0105] The spun nanofiber membrane is heat-treated to obtain a modified fiberglass composite facing material; the diphenylmethane diisocyanate in the nanofiber membrane crosslinks with the hydroxyl groups on the surface of the activated fiberglass facing material to generate polyurethane, and bridges are formed between the fiber membrane layer and the substrate through the urethane structure, improving the mechanical properties of the composite facing material. Among them, the heat treatment temperature is 130 °C and the time is 60 min.

[0106] Example 5 A preparation method of a polyvinylidene fluoride / polyurethane crosslinked modified fiberglass composite facing material

[0107] Including the following steps:

[0108] (1)Activation treatment of fiberglass facing material

[0109] The fiberglass cloth coated with adhesive and kraft paper are laminated together and sent into a laminating composite machine. After pressing at a temperature of 150 °C and a pressure of 1 MPa for 12 h, a fiberglass facing semi-finished product is obtained. It is immersed in a 10% (v / v) hydrochloric acid solution and impregnated at room temperature for 3 h; then it is washed two to three times by shaking with anhydrous ethanol and deionized water in turn, dried with dry nitrogen on the surface, air-dried at room temperature, and then dried in a blast drying oven at 105 °C for 2 h to remove excess impurities on the surface and generate more silanol groups (Si-OH) on the fiberglass facing to supply the crosslinking reaction with diphenylmethane diisocyanate later, and a fiberglass facing material with a clean surface and rich in silanol groups, that is, an activated fiberglass facing material, is prepared.

[0110] The fiberglass cloth is a plain weave non-alkali cloth with a thickness of 5 mm;

[0111] The grammage of the kraft paper is 100 g / m 2 , and the thickness is 0.15 mm;

[0112] The lamination is to laminate one side of the glass fiber cloth coated with the adhesive and the kraft paper;

[0113] The adhesive is an organosilicon-modified acrylate pressure-sensitive adhesive, with the model of PYS2 type, provided by Zhejiang Jinjia Technology Co., Ltd.;

[0114] The coated thickness of the adhesive after curing on the glass fiber cloth is 22 μm.

[0115] (2) Preparation of electrospinning solution and electrospray solution

[0116] Mix polyvinylidene fluoride (PVDF) and diphenylmethane diisocyanate (MDI), and then dissolve them in N-N dimethylformamide (DMF) solvent. After stirring, a uniform PVDF / MDI electrospinning solution is obtained. Among them, PVDF accounts for 20 wt% of the whole spinning solution, and MDI accounts for 9 wt% of the whole spinning solution;

[0117] Use titanium dioxide (TiO2) as an antibacterial agent, disperse it in DMF, and ultrasonicate it for 1 hour by ultrasonic wave to prepare a TiO2 electrospray solution, in which the mass content of titanium dioxide is 9 wt%.

[0118] (3) Preparation of nanofiber membrane

[0119] Take the activated glass fiber facing material prepared in step (1) as the receiving substrate. Take an appropriate amount of PVDF / MDI electrospinning solution and TiO2 electrospray solution and inject them into an electrospinning machine (the electrospinning machine includes 5 spinnerets). Using the "side-by-side" electrospinning method, prepare a layer of nanofiber membrane on the surface of the activated glass fiber facing material. The nanofiber membrane includes the polymer PVDF / MDI and TiO2, and the thickness of the fiber membrane is 25 μm;

[0120] Among them, the PVDF / MDI electrospinning solution deposits the polymer PVDF / MDI on the substrate in the form of nanofibers through spinneret A, and the TiO2 electrospray solution deposits TiO2 inorganic particles on the substrate surface in the form of electrostatic spray through spinneret B. Specifically, the ratio of the number of spinnerets of A and B is 2:3, and the flow rate of each spinneret is 4 mL / h; the distance between the spinneret and the receiving substrate is 28 cm; the spinning time is 2.5 h.

[0121] (4) Crosslinking modification of MDI and glass fiber silanol groups

[0122] The spun nanofiber membrane is heat-treated to obtain a modified glass fiber composite facing material; diphenylmethane diisocyanate in the nanofiber membrane crosslinks and modifies with the hydroxyl groups on the surface of the activated glass fiber facing material to generate polyurethane, and bridges between the fiber membrane layer and the substrate through the urethane structure, improving the mechanical properties of the composite facing material. Among them, the heat treatment temperature is 140 °C and the time is 30 min.

[0123] Example 6 A preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite facing material

[0124] It includes the following steps:

[0125] (1) Activation treatment of the glass fiber facing material

[0126] The glass fiber cloth coated with the adhesive and the kraft paper are laminated together and sent into a laminating composite machine, and a semi-finished glass fiber facing product is prepared by pressing at a temperature of 150 °C and a pressure of 1 MPa for 12 h. It is immersed in a 10% (v / v) hydrochloric acid solution and impregnated at room temperature for 2 h; then it is washed two to three times by shaking with absolute ethanol and deionized water in turn, dried with dry nitrogen on the surface, air-dried at room temperature and then dried in a forced-air drying oven at 105 °C for 2 h to remove excess impurities on the surface and generate more silanol groups (Si-OH) on the glass fiber facing to supply the cross-linking reaction with diphenylmethane diisocyanate later, and a glass fiber facing material with a clean surface and rich in silanol groups, that is, the activated glass fiber facing material, is prepared.

[0127] The glass fiber cloth is a plain weave non-alkali cloth with a thickness of 5 mm;

[0128] The grammage of the kraft paper is 100 g / m 2 , and the thickness is 0.15 mm;

[0129] The lamination is to laminate one side of the glass fiber cloth coated with the adhesive and the kraft paper;

[0130] The adhesive is an organosilicon-modified acrylate pressure-sensitive adhesive, model PYS2, provided by Zhejiang Jinjia Technology Co., Ltd.;

[0131] The coating thickness of the adhesive after curing on the glass fiber cloth is 20 μm.

[0132] (2) Preparation of the electrospinning solution and the electrospraying solution

[0133] Mix polyvinylidene fluoride (PVDF) and diphenylmethane diisocyanate (MDI), then dissolve them in N,N-dimethylformamide (DMF) solvent. After stirring, a uniform PVDF / MDI electrospinning solution is obtained. Among them, PVDF accounts for 25wt% of the whole spinning solution, and MDI accounts for 10wt% of the whole spinning solution.

[0134] Use titanium dioxide (TiO2) as an antibacterial agent, disperse it in DMF, and ultrasonicate it for 1 hour to prepare a TiO2 electrospray solution, where the mass content of titanium dioxide is 10wt%.

[0135] (3) Preparation of nanofiber membrane

[0136] Take the activated glass fiber facing material prepared in step (1) as the receiving substrate. Take an appropriate amount of PVDF / MDI electrospinning solution and TiO2 electrospray solution and inject them into an electrospinning machine (the electrospinning machine includes 5 spinnerets). Using the "side-by-side" electrospinning method, prepare a layer of nanofiber membrane on the surface of the activated glass fiber facing material. The nanofiber membrane includes the polymer PVDF / MDI and TiO2, and the thickness of the fiber membrane is 10 - 50μm.

[0137] Among them, the PVDF / MDI electrospinning solution deposits the polymer PVDF / MDI on the substrate in the form of nanofibers through spinneret A, and the TiO2 electrospray solution deposits TiO2 inorganic particles on the substrate surface in the form of electrospray through spinneret B. Specifically, the ratio of the number of spinnerets of A and B is set to 1:4, and the flow rate of each spinneret is 5mL / h; the distance between the spinneret and the receiving substrate is 30cm; the spinning time is 1.5h.

[0138] (4) Crosslinking modification of MDI and silanol groups on glass fiber

[0139] Heat-treat the spun nanofiber membrane to obtain a modified glass fiber composite facing material; the diphenylmethane diisocyanate in the nanofiber membrane crosslinks with the hydroxyl groups on the surface of the activated glass fiber facing material to generate polyurethane, and bridges between the fiber membrane layer and the substrate through the urethane structure, improving the mechanical properties of the composite facing material. Among them, the heat treatment temperature is 150°C and the time is 10min.

[0140] The performance indexes of the composite facing materials prepared in Examples 1 - 6 are shown in the following table:

[0141] .

Claims

1. A preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material, characterized in that: It includes the activation treatment of the glass fiber facing material, the preparation of the nanofiber membrane, and crosslinking modification; The method for the activation treatment of the glass fiber facing material is to impregnate the semi-finished glass fiber facing material with hydrochloric acid solution for 2 - 3 h, and then obtain the activated glass fiber facing material through washing and drying; the method for the preparation of the nanofiber membrane is to prepare a nanofiber membrane containing polyvinylidene fluoride, diphenylmethane diisocyanate, and titanium oxide on the surface of the activated glass fiber facing material by electrospinning; For the crosslinking modification, diphenylmethane diisocyanate in the nanofiber membrane reacts with the hydroxyl groups on the surface of the activated glass fiber facing material to form polyurethane.

2. The preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material according to claim 1, characterized in that: For the crosslinking modification, heat treatment is carried out on the nanofiber membrane and the activated glass fiber facing material, and the temperature of the heat treatment is 100 - 150 °C, and the time is 10 - 180 min.

3. The preparation method of a polyvinylidene fluoride / polyurethane crosslinked and modified glass fiber composite veneer material according to claim 1, characterized in that: The method for the preparation of the nanofiber membrane is to use the activated glass fiber facing material as the receiving substrate, and the receiving distance is 20 - 30 cm; the PVDF / MDI electrospinning solution and the TiO2 electrospray solution are respectively ejected, and the polymer PVDF / MDI and the TiO2 inorganic particles are simultaneously deposited on the surface of the substrate, and a nanofiber membrane is prepared on the surface of the activated glass fiber facing material, and the thickness of the fiber membrane is 10 - 50 μm.

4. The preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material according to claim 3, characterized in that: The spinning speed of the PVDF / MDI electrospinning solution is 4 - 9 mL / h; the electrospray speed of the TiO2 electrospray solution is 1 - 20 mL / h.

5. The preparation method of a polyvinylidene fluoride / polyurethane crosslinked modified glass fiber composite veneer material according to claim 3, characterized in that: In the PVDF / MDI electrospinning solution, the content of PVDF is 10 - 25 wt%, and the content of MDI is 1 - 10 wt%; in the TiO2 electrospray solution, the content of TiO2 is 1 - 10 wt%.

6. The preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material according to claim 1, characterized in that: The method for the preparation of the semi-finished glass fiber facing material is to laminate the glass fiber cloth coated with the adhesive and kraft paper, and then press for 11.5 - 12.5 h under the conditions of a temperature of 148 - 152 °C and a pressure of 0.8 - 1.2 MPa to obtain the semi-finished glass fiber facing material.

7. The preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material according to claim 6, characterized in that: The coating thickness of the adhesive after curing on the glass fiber cloth is 18 ± 4 μm.

8. The preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material according to claim 6, characterized in that: The adhesive is an organosilicon-modified acrylate pressure-sensitive adhesive.

9. The preparation method of a polyvinylidene fluoride / polyurethane cross-linked modified glass fiber composite veneer material according to claim 6, characterized in that: The fiberglass cloth is a plain weave non-alkali cloth with a thickness of 4.5 - 5.5 mm; the grammage of the kraft paper is 98 - 102 g / m 2 , and the thickness is 0.14 - 0.16 mm.