Low-temperature-resistant composite roller blind fabric and preparation method thereof

Abstract

The application belongs to the field of roller blind fabrics, and particularly relates to a low-temperature-resistant composite roller blind fabric and a preparation method thereof. The method comprises the following steps: 1) pre-treating basalt fibers to prepare functionalized fibers; 2) mixing a composite resin matrix and the functionalized fibers to prepare a prepreg; 3) coating the prepreg on the surface of a substrate and hot-pressing to prepare a precursor; and 4) performing gradient curing treatment on the precursor to prepare the low-temperature-resistant composite roller blind fabric. The application adopts a composite resin system containing an epoxy group and a siloxane group, enhances the low-temperature toughness through intermolecular hydrogen bonds and a crosslinking network, and strengthens the interfacial bonding strength of the resin and the fiber substrate through the introduction of hot-pressing and a sectional curing process.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of roller shutter fabrics, and particularly relates to a low-temperature-resistant composite roller shutter fabric and a preparation method thereof. BACKGROUND

[0002] In the field of traditional roller shutter materials, common materials such as polyvinyl chloride (PVC) or ordinary polyester are prone to embrittlement and cracking in an environment with a temperature below-20℃. At present, the low-temperature-resistant modification technology adopted for this problem mostly relies on polyurethane for toughening treatment. However, this method has many drawbacks, on the one hand, the environmental performance is poor, and on the other hand, the weather resistance is difficult to meet the actual demand. From the perspective of existing technology, the interfacial bonding strength between the resin matrix and the reinforcing phase is obviously insufficient. This key problem directly leads to low stress transfer efficiency under low temperature conditions, thereby affecting the performance of the entire roller shutter material.

[0003] The traditional roller shutter fabric is particularly prone to embrittlement and cracking in a low-temperature environment, especially the material with polyurethane as the matrix. Although in the prior art, attempts have been made to add plasticizers or use blending modification methods to improve the low-temperature performance of the material, but these measures still have a series of defects. For example, the plasticizer is prone to migration, and the interfacial bonding is weak, which makes the overall performance of the material unstable. In addition, the conventional processing technology has great difficulty in realizing efficient bonding of the resin and the substrate, which further increases the risk of delamination of the material in a low-temperature environment. SUMMARY

[0004] The technical scheme of the present application aims to solve the technical problems of low-temperature embrittlement and insufficient interfacial bonding strength of existing roller shutter fabrics, and provides a low-temperature-resistant composite roller shutter fabric and a preparation method thereof.

[0005] The main purpose of the present application is: 1. to strengthen the mechanical properties of the roller shutter fabric under low-temperature conditions.

[0006] 2. to enhance the interfacial bonding strength of the roller shutter fabric.

[0007] To achieve the above-mentioned purposes, the present application adopts the following technical scheme.

[0008] A preparation method of a low-temperature-resistant composite roller shutter fabric, the method comprising: 1) pretreating basalt fibers to prepare functionalized fibers.

[0009] 2) mixing a composite resin matrix with the functionalized fibers to prepare a prepreg.

[0010] 3) coating the prepreg on the surface of the substrate and hot pressing to form a precursor.

[0011] 4) performing gradient curing treatment on the precursor to obtain a low-temperature-resistant composite roller shutter fabric.

[0012] As preferred, the basalt fiber in step 1) has a diameter of 50-100 nm, an aspect ratio >200, and a surface roughness Ra of 0.8-1.2 μm.

[0013] As preferred, the pretreatment in step 1) is etching the fiber surface with a hydrochloric acid solution having a mass concentration of 55-60 % for 30-45 min, filtering, and then placing in a silane coupling agent KH-570 aqueous solution having a concentration of 1-2 wt%, and ultrasonic treatment for 20-30 min at a temperature of 60-80 ℃, and filtering and drying to a water content <0.5 %.

[0014] As preferred, the composite resin matrix in step 2) is mixed and compounded from epoxy acrylate and silicone-modified alkyd resin at a mass ratio of (3-3.5):1, and stirring and mixing at a rotation speed of 40-60 rpm and a temperature of 80-100 ℃ for 30-40 min; the epoxy acrylate has an epoxy equivalent weight of 180-220 g / eq; and the silicone-modified alkyd resin has a hydroxyl value of 50-70 mg KOH / g.

[0015] As preferred, the functionalized fiber in step 2) is added in an amount of 20-30 wt%, and dispersed under the conditions of a vacuum degree ≤-0.08 MPa and a shear rate of 2000-2500 rpm for 15-20 min.

[0016] As preferred, the substrate in step 3) is a plain weave glass fiber cloth having a thickness of 0.23-0.27 mm; and the coating process in step 3) is knife coating, and the coating is performed on both sides under the conditions of a temperature of 60-70 ℃, a coating speed of 24 m / min, a coating gap of 0.5-0.8 mm, and a coating thickness of 0.12-0.14 mm.

[0017] As preferred, the hot press forming conditions in step 3) include first stage processing and second stage processing, specifically: the first stage processing controls a pressure of 0.3-0.5 MPa and a temperature of 80-90 ℃, and is maintained for 5-8 min; and the second stage processing controls a pressure of 1.0-1.2 MPa and a temperature of 100-110 ℃, and is maintained for 10-15 min.

[0018] Pre-curing stage: maintaining for 20-30 min under the environmental conditions of temperature 60-80 DEG C and pressure 0.5-0.8 MPa; main curing stage: maintaining for 40-50 min under the environmental conditions of nitrogen atmosphere and temperature 120-130 DEG C, adding 0.5-1.0 Phr of dicumyl peroxide in the process; post-curing stage: maintaining for 15-20 min under the environmental conditions of vacuum degree <=-0.09 MPa and temperature 150-160 DEG C.

[0019] A low-temperature-resistant composite roller shutter fabric.

[0020] In the technical scheme of the application, the core is that the mechanical properties and structural stability of the material in a low-temperature environment are significantly improved through modification of the functional groups of the composite resin material and optimization of the processing technology, and the strong interfacial bonding of the resin and the base material is ensured through staged curing and hot pressing, so that the low-temperature failure phenomenon caused by the migration of traditional plasticizers is solved.

[0021] In the application, basalt fibers are etched and coupled and grafted in the first step. Hydrogen ions selectively dissolve the silicon-rich phase on the surface of the fibers, producing nanoscale grooves, increasing the specific surface area, and enhancing the mechanical anchoring effect. Subsequently, the methoxy group of KH-570 is hydrolyzed to form silanol (Si-OH), which condenses with the hydroxyl groups on the surface of the fibers to form Si-O-Si covalent bonds. The methacryloyloxy group provides active sites for subsequent free radical grafting. In the second step, the fiber material is blended with the resin matrix. The rigid epoxy skeleton of the epoxy acrylate provides low-temperature creep resistance, and the epoxy groups form a hydrogen bond network with the -Si-O- chains of the silicone resin, inhibiting the freezing of molecular chains at low temperatures. In addition, the long-chain alkyl groups of the silicone resin absorb impact energy through intermolecular entanglement, compensating for the brittleness of the resin at low temperatures. Furthermore, high shear force breaks the fiber agglomeration during the process, and the vacuum environment eliminates bubbles, generates frictional charges, and promotes uniform dispersion of the fibers. In the third step, stepwise pressure increase is used to avoid displacement of the fibers in the material and to eliminate most of the thermal stress in the material. In the fourth step of gradient curing, the pre-curing stage triggers the condensation reaction of the silane coupling agent -Si-O- bond to form primary crosslinking points. In the main curing stage, dicumyl peroxide decomposes to generate free radicals, which promote the grafting of the methacryloyloxy group with the resin double bonds to form a through-type interpenetrating network. In the post-curing stage, residual stress in the material is released in a high-temperature environment, and low-molecular-weight byproducts present in the material are removed under the action of vacuum.

[0022] In the present application, the hydrogen bond between the epoxy group and the Si-O chain reversibly breaks at low temperature, consuming energy, while the Si-O-Si covalent bond maintains the stability of the skeleton, achieving a dynamic balance between "sacrificial bonds" and "load-bearing bonds", and completing the functional group synergistic toughening mechanism. The epoxy group in the epoxy acrylate forms a hydrogen bond network with the siloxane chain of the silicone-modified alkyd resin. This network reversibly breaks and recombines at low temperature, dissipating impact energy through the "sacrificial bond" mechanism. The long-chain alkyl groups of the silicone resin form physical crosslinking points through intermolecular entanglement, and their relaxation time matches the frequency of low-temperature impact loads, achieving dynamic energy absorption. In addition, the -Si-O-Si- covalent bond of silane coupling agent KH-570 chemically bonds to the surface of basalt fiber, forming a rigid interfacial layer with a fracture toughness significantly stronger than traditional physical adsorption interfacial strength.

[0023] At the same time, by controlling the temperature and pressure sequence, the condensation reaction is completed before the free radical reaction, avoiding network defects caused by competition. The pre-curing stage triggers the siloxane condensation reaction first, ensuring that most of the condensation reaction has been completed; the main curing stage initiates the free radical grafting reaction of dicumyl peroxide, avoiding network defects caused by competition between the two stages, and the linear segments of the epoxy acrylate and the three-dimensional network of the silicone resin interpenetrate each other, forming a double continuous phase structure. At this time, through temperature-pressure time sequence control, a chemical bond density gradient is formed at the fiber / resin interface, which makes the crack propagation need to pass through regions with different bonding strengths, consuming energy.

[0024] The advantages of the present application are: (1) a composite resin system containing epoxy groups and siloxane groups is used to enhance low-temperature toughness through intermolecular hydrogen bonds and crosslinking networks; (2) hot pressing and segmented curing process are introduced to strengthen the interfacial bonding strength of the resin and the fiber substrate. DETAILED DESCRIPTION

[0025] The present application will be further clarified by the following specific examples. Those skilled in the art can implement the present application based on these descriptions. In addition, the examples of the present application involved in the following description are generally only a part of the embodiments of the present application, not all. Therefore, all other embodiments obtained by those skilled in the art based on the examples in the present application without creative labor should be within the scope of protection of the present application.

[0026] Unless otherwise specified, the raw materials used in the examples of the present application are commercially available or can be obtained by those skilled in the art; unless otherwise specified, the methods used in the examples of the present application are methods mastered by those skilled in the art.

[0027] Example 1: Preparation method of a low-temperature-resistant composite roller blind fabric.

[0028] The method comprises: 1) selecting basalt fibers with a diameter of 50 nm, an aspect ratio of 200, and a surface roughness Ra of 0.8 μm, pretreating the basalt fibers, etching the fiber surface with a hydrochloric acid solution with a mass concentration of 58 % for 30 min, then ultrasonic treating with a silane coupling agent KH-570 with a concentration of 1 wt% at a temperature of 60 ℃ for 30 min, and finally drying at a temperature of 120 ℃ to a water content of 0.5 %, to prepare functionalized fibers.

[0029] 2) mixing and compounding epoxy acrylate and silicone-modified alkyd resin at a mass ratio of 3:1, stirring and mixing at a speed of 40 rpm and a temperature of 80 ℃ for 40 min to control the viscosity at 5000 mPa·s, to prepare a composite resin matrix. The epoxy equivalent weight of the epoxy acrylate is 180 g / eq, and the hydroxyl value of the silicone-modified alkyd resin is 50 mgKOH / g.

[0030] 3) mixing the composite resin matrix with the functionalized fibers, the addition amount of the functionalized fibers being 20 wt%, and dispersing at a vacuum degree of -0.08 MPa and a shear rate of 2000 rpm for 20 min, to prepare a prepreg.

[0031] 4) coating the prepreg on both sides of a plain-woven glass fiber cloth with a thickness of 0.23 mm, using a knife coating, and coating at a temperature of 60 ℃, a coating speed of 24 m / min, and a coating gap of 0.5 mm to a thickness of 0.12 mm. Then, hot pressing at a first stage pressure of 0.3 MPa and a temperature of 80 ℃ for 8 min, and a second stage pressure of 1.0 MPa and a temperature of 100 ℃ for 15 min, to prepare a precursor.

[0032] 5) gradient curing the precursor, pre-curing at a temperature of 60 ℃ and a pressure of 0.5 MPa for 30 min, main curing at a nitrogen atmosphere and a temperature of 120 ℃ for 50 min, adding 0.5 Phr of dicumyl peroxide in the process, and post-curing at a vacuum degree of -0.09 MPa and a temperature of 150 ℃ for 20 min, to prepare a low-temperature-resistant composite roller shutter fabric.

[0033] The composite roller shutter fabric prepared in the example was subjected to performance detection, and the specific characterization results are shown in Table 1.

[0034] Tensile property test: the composite roller shade fabric prepared in the examples was prepared into 5 groups of standard I type dumbbell test samples with effective size of length 115 mm, gauge length 50 mm, width 10 mm, thickness 2 mm, and tensile tested using a universal material testing machine at temperature 24 °C and tensile rate 5 mm / min until breaking, and the tensile strength, elongation at break and elastic modulus were recorded, and the average value was calculated.

[0035] Bending strength test: the composite roller shade fabric prepared in the examples was prepared into 5 groups of test samples with length 80 mm, width 10 mm, thickness 4 mm, and tested using a three-point bending test method under test conditions of span 64 mm, pressure head radius 5 mm, and loading rate 2 mm / min until the test sample broke or the deformation reached 5 %, and the bending strength and bending modulus of the test sample were recorded, and the average value was calculated.

[0036] Abrasion resistance test: the composite roller shade fabric prepared in the examples was prepared into circular sheet test samples with diameter 100 mm, thickness 2 mm, and surface flatness 0.1 μm, and tested using a Taber abrasion tester with load 500 g, using H18 grinding wheel for 1000 rotations, and the mass of the abrasion debris was recorded.

[0037] Chemical corrosion resistance: the composite roller shade fabric prepared in the examples was prepared into 6 test samples with size 50×50×2 mm 3 , and divided into two groups, the acidic immersion liquid was 10 % sulfuric acid solution with pH 4.2, and the alkaline immersion liquid was 5 % sodium chloride solution, and immersed at temperature 25 °C for 168 h, and stirred once every 24 h, and then the test samples were taken out, washed with deionized water and dried to constant weight, and the tensile strength retention rate after immersion was tested.

[0038] Table 1: performance characterization results:

[0039] The above Table 1 characterization results show that the low-temperature-resistant composite roller shade fabric prepared in Example 1 exhibits excellent mechanical properties. In the tensile property test, the fabric shows a high tensile strength of 85.7 MPa, an elongation at break of 18.2%, and an elastic modulus of 4.2 GPa. These parameters together prove that the fabric has good strength and toughness when subjected to external forces. The dynamic fracture-recombination energy consumption of the epoxy-based / siloxane hydrogen bond network in the material, combined with the uniform stress distribution of the epoxy acrylate-silicone IPN structure, achieves a synergistic improvement in strength and toughness. The bending strength test results are 122.7 MPa and the bending modulus is 3.8 GPa, indicating that the fabric can effectively resist external forces during bending deformation and maintain the stability of the structure. The gradient curing process in the material eliminates interfacial residual stress, and the basalt fiber-Si-O-Si covalent bond interface suppresses crack initiation, so that the bending failure needs to break through the chemical bond breaking energy barrier. The abrasion resistance test shows that after 1000 revolutions of the Taber abrasion tester, the abrasive mass is only 12.6 mg / 1000 revolutions, showing excellent wear resistance. In the chemical corrosion resistance test, the tensile strength retention rates of the fabric after immersion in acidic and alkaline solutions for 168 h are 92.7% and 95.2%, respectively, indicating that the fabric has good chemical corrosion resistance and can maintain stable mechanical properties in harsh environments. The material has a small porosity and a dense IPN body phase constructed by two-stage curing, and the hydrophobicity of the siloxane segment blocks the penetration path of the medium, while the fiber interface polarization effect suppresses electrochemical corrosion.

[0040] Example 2: A method for preparing a low-temperature-resistant composite roller shade fabric.

[0041] The method comprises: 1) selecting basalt fibers with a diameter of 75 nm, an aspect ratio of 200, and a surface roughness Ra of 1.0 μm, pretreating the basalt fibers, etching the fiber surface with a hydrochloric acid solution with a mass concentration of 58% for 37 min, then ultrasonic treating with a silane coupling agent KH-570 with a concentration of 1.5 wt% at a temperature of 70 ℃ for 25 min, and finally drying at a temperature of 120 ℃ to a water content of 0.5%, to prepare functionalized fibers.

[0042] 2) Mix and compound the epoxy acrylate and silicone-modified alkyd resin at a mass ratio of 3.3:1, stir and mix at a speed of 50 rpm and a temperature of 90 ℃ for 35 min, and control the viscosity at 6500 mPa·s to prepare a composite resin matrix. The epoxy acrylate has an epoxy equivalent weight of 200 g / eq, and the silicone-modified alkyd resin has a hydroxyl value of 60 mgKOH / g.

[0043] 3) The functionalized fiber was mixed with the matrix resin at a content of 25 wt% and dispersed for 17 min under the conditions of a vacuum degree of -0.08 MPa and a shear rate of 2250 rpm to prepare a prepreg.

[0044] 4) The prepreg was coated on both sides of a plain-woven glass fiber cloth with a thickness of 0.25 mm by using a knife coating method under the conditions of a temperature of 65 °C, a coating speed of 24 m / min, and a coating gap of 0.6 mm to obtain a coating thickness of 0.13 mm. Then, the prepreg was hot-pressed under the conditions of a first-stage pressure of 0.4 MPa and a temperature of 85 °C for 6 min, and a second-stage pressure of 1.1 MPa and a temperature of 105 °C for 13 min to obtain a precursor.

[0045] 5) The precursor was gradiently cured under the conditions of a pre-curing stage of a temperature of 70 °C and a pressure of 0.6 MPa for 25 min, a main curing stage of a temperature of 125 °C in a nitrogen atmosphere for 45 min with the addition of 0.75 Phr of dicumyl peroxide, and a post-curing stage of a temperature of 155 °C under a vacuum degree of ≤-0.09 MPa for 17 min to obtain a low-temperature-resistant composite roller shade fabric.

[0046] The composite roller shade fabric prepared in the example was subjected to performance detection, and the specific characterization results are shown in Table 2 below.

[0047] Tensile property detection: The composite roller shade fabric prepared in the example was prepared into 5 groups of standard I-shaped dumbbell-shaped detection samples with an effective size of a length of 115 mm, a gauge length of 50 mm, a width of 10 mm, and a thickness of 2 mm, and was stretched using a universal material testing machine at a temperature of 24 °C and a stretching rate of 5 mm / min until fracture to record the tensile strength, elongation at break, and elastic modulus, and to calculate the average value.

[0048] Bending strength detection: The composite roller shade fabric prepared in the example was prepared into 5 groups of detection samples with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm, and was detected using a three-point bending detection method under the detection conditions of a span of 64 mm and a pressure head radius of 5 mm at a loading rate of 2 mm / min until the detection sample was fractured or the deformation amount reached 5% to record the bending strength and bending modulus of the detection sample, and to calculate the average value.

[0049] Wear resistance detection: The composite roller shade fabric prepared in the example was prepared into a circular sheet detection sample with a diameter of 100 mm, a thickness of 2 mm, and a surface flatness of 0.1 μm, and was detected using a Taber abrasion tester under the conditions of a load of 500 g and 1000 rotations of a H18 grinding wheel to record the mass of the abrasion.

[0050] Chemical corrosion resistance: the composite roller shade fabric prepared in the example was prepared into 50x50x2 mm 3 6 test samples, divided into two groups, the acidic immersion liquid was a 10% sulfuric acid solution with pH 4.2, the alkaline immersion liquid was a 5% sodium chloride solution, and the test samples were immersed in an environment at a temperature of 25°C for 168 h, with stirring once every 24 h, and then the test samples were taken out, washed with deionized water and dried to constant weight, and the tensile strength retention rate after immersion was tested.

[0051] Table 2: performance characterization results:

[0052] Analyzing the above Table 2 characterization results, the low-temperature-resistant composite roller shade fabric prepared in Example 2 also exhibited excellent mechanical properties.

[0053] Example 3: a preparation method of a low-temperature-resistant composite roller shade fabric.

[0054] The method comprises: 1) selecting basalt fibers with a diameter of 100 nm, an aspect ratio of 200, and a surface roughness Ra of 1.2 μm, pretreating the basalt fibers, etching the fiber surface with a 58% mass concentration hydrochloric acid solution for 45 min, then ultrasonic treating with a 2 wt% concentration silane coupling agent KH-570 at a temperature of 80°C under environmental conditions for 20 min, and finally drying at a temperature of 120°C under environmental conditions to a water content of 0.5%, to prepare functionalized fibers.

[0055] 2) mixing and compounding epoxy acrylate and silicone-modified alkyd resin at a mass ratio of 3.5:1, stirring and mixing at a speed of 60 rpm and a temperature of 100°C for 30 min, controlling the viscosity at 8000 mPa·s, and preparing a composite resin matrix. Among them: the epoxy equivalent weight of epoxy acrylate is 220 g / eq, and the hydroxyl value of silicone-modified alkyd resin is 70 mg KOH / g.

[0056] 3) mixing the composite resin matrix with the functionalized fibers, the addition amount of the functionalized fibers being 30 wt%, dispersing under the conditions of a vacuum degree of-0.08 MPa and a shear rate of 2500 rpm for 15 min, to prepare a prepreg.

[0057] 4) The plain-woven glass fiber cloth with a thickness of 0.27 mm was coated with prepreg on both sides by using a doctor blade coating method under the conditions of a temperature of 70 °C, a coating speed of 24 m / min, and a coating gap of 0.8 mm, and the coating thickness was 0.14 mm. Then, the precursor was prepared by hot pressing under the conditions of a first-stage pressure of 0.5 MPa and a temperature of 90 °C for 5 min, and a second-stage pressure of 1.2 MPa and a temperature of 110 °C for 10 min.

[0058] 5) The precursor was gradiently cured under the conditions of a pre-curing stage of maintaining at a temperature of 80 °C and a pressure of 0.8 MPa for 20 min, a main curing stage of maintaining at a temperature of 130 °C in a nitrogen atmosphere for 40 min, and a post-curing stage of maintaining at a temperature of 160 °C under a vacuum degree of -0.09 MPa for 15 min, and 1.0 Phr of dicumyl peroxide was added during the process, to obtain the low-temperature-resistant composite roller shutter fabric.

[0059] The composite roller shutter fabric prepared in the example was subjected to performance detection, and the specific characterization results are shown in Table 3.

[0060] Tensile property detection: The composite roller shutter fabric prepared in the example was prepared into 5 groups of standard I-shaped dumbbell-shaped detection samples with an effective size of a length of 115 mm, a gauge length of 50 mm, a width of 10 mm, and a thickness of 2 mm, and was stretched at a temperature of 24 °C and a stretching rate of 5 mm / min using a universal material testing machine until fracture, and the tensile strength, elongation at break, and elastic modulus were recorded, and the average values were calculated.

[0061] Bending strength detection: The composite roller shutter fabric prepared in the example was prepared into 5 groups of detection samples with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm, and was detected using a three-point bending detection method under the detection conditions of a span of 64 mm and a pressure head radius of 5 mm, and at a loading rate of 2 mm / min until the detection sample was fractured or the deformation amount reached 5 %, and the bending strength and bending modulus of the detection sample were recorded, and the average values were calculated.

[0062] Wear resistance detection: The composite roller shutter fabric prepared in the example was prepared into a circular sheet detection sample with a diameter of 100 mm, a thickness of 2 mm, and a surface flatness of 0.1 μm, and was detected using a Taber abrasion tester under the conditions of a load of 500 g and 1000 rotations using a H18 grinding wheel, and the mass of the abrasion powder was recorded.

[0063] Chemical corrosion resistance: The composite roller shutter fabric prepared in the example was prepared into a 50×50×2 mm 3The 6 test samples of the above were divided into two groups, the acid soaking solution was 10% sulfuric acid solution with pH 4.2, the alkaline soaking solution was 5% sodium chloride solution, and the soaking was carried out at 25°C for 168 h, stirring once every 24 h, then taking out the test sample, washing with deionized water and drying to constant weight, and testing the tensile strength retention rate after soaking.

[0064] Table 3: Performance characterization results

[0065] Analyzing the above Table 3 characterization results, the low-temperature resistant composite roller shade fabric prepared in Example 3 also exhibits excellent mechanical properties.

[0066] Comparative Example 1: Based on Example 2, only the resin matrix component was changed, and the remaining steps were the same as Example 2. The specific settings are shown in the following Table 4:

[0067] Table 4: Process adjustment comparison table

[0068]

[0069] The performance test method of the product of the comparative example is completely consistent with Example 1, and the characterization results are shown in the following Table 5.

[0070] Table 5: Performance characterization results comparison table

[0071] The analysis of the above Table 4-Table 5 characterization results, compared with Example 2, only using epoxy acrylate as the base resin of Comparative Example D1-1, in tensile properties, bending strength, wear resistance and chemical corrosion resistance and other key performance indicators have a significant decline. Specifically, the tensile strength of D1-1 is only 69.8 MPa, far lower than 85.8 MPa of Example 2, the elongation at break is also decreased to 3.9 %, showing that the strength and toughness of the material under external force are greatly reduced. The increase of elastic modulus to 5.8 GPa, which may indicate that the material becomes more rigid and lacks toughness. The bending strength test results are 88.6 MPa, and the bending modulus is 5.2 GPa, which is also far lower than the data of Example 2, indicating that the fabric's ability to resist external force during bending deformation is significantly reduced. The wear resistance test shows that the D1-1 wear debris mass is 25.3 mg / 1000 turns, which is significantly higher than 12.5 mg / 1000 turns of Example 2, and the wear resistance is poor. In the chemical corrosion resistance test, the tensile strength retention rate of D1-1 after immersion in acidic and alkaline solutions is 55.4 % and 62.6 % respectively, which is far lower than 92.8 % and 95.3 % of Example 2, indicating that the fabric has poor chemical corrosion resistance and is difficult to maintain stable mechanical properties in harsh environments. These results show that the selection of composite resin matrix is crucial to the mechanical properties of low-temperature composite roller blind fabric, and the introduction of organosilicon modified alkyd resin and epoxy acrylate to form IPN structure can significantly improve the comprehensive performance of the fabric.

[0072] In addition, the performance test was carried out with Example 2, and the specific characterization results are shown in Table 6 below.

[0073] Low temperature tensile test: the composite roller blind fabric prepared by the examples and comparative examples was prepared into 5 groups of standard I type dumbbell type test samples with effective size of length 115 mm, gauge length 50 mm, width 10 mm, thickness 2 mm, under the condition of temperature-10 ℃, tensile rate 2 mm / min, using universal material testing machine to stretch until fracture, recording the tensile strength, elongation at break, and calculating the average value.

[0074] Low temperature impact toughness test: the composite roller blind fabric prepared by the examples and comparative examples was prepared into 80×10×4mm 3 Notched test sample (notch depth 2 mm, radius 0.25 mm), immersed in liquid nitrogen to-50 ℃ and tested immediately, with a pendulum impact of 7.5 J, measuring the impact strength and crack propagation path.

[0075] Low-temperature bending fatigue test: the composite roller blind fabric prepared by the examples and comparative examples was prepared into 5 groups of test samples with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm. The three-point bending cyclic load was used at a temperature of -10 ℃ (stress ratio R = 0.1, frequency 5 Hz), the maximum stress was 60% of the room temperature bending strength, and the test was terminated when the sample was broken or the number of cycles reached 10 6 times, and whether cracks appeared on the test sample was observed.

[0076] Table 6: Performance characterization results comparison table

[0077] By analyzing the above characterization data, in the low-temperature tensile test, the composite roller blind fabric prepared in Example 2 exhibited a higher tensile strength of 80.6 MPa, and the elongation at break was 16.4%, indicating that the fabric could still maintain good strength and toughness in extremely low-temperature environments. In contrast, the tensile strength of D1-1 was only 38.4 MPa, and the elongation at break was also significantly reduced to 3.2%, showing that the mechanical properties of the material significantly deteriorated under low-temperature conditions.

[0078] The low-temperature impact toughness test results showed that the impact strength of Example 2 was 19.6 kJ / m2, the crack propagation rate was 4.5 mm / ms, and no clear cracks were observed during the entire test process, indicating that the fabric had good impact resistance and toughness at low temperatures. The impact strength of D1-1 was only 4.2 kJ / m2, the crack propagation rate was as high as 12.8 mm / ms, and cracks rapidly appeared at surface defects, indicating that its low-temperature impact toughness was poor and it was prone to damage when impacted.

[0079] The low-temperature bending fatigue test showed that the composite roller blind fabric of Example 2 still did not have cracks after 106 three-point bending cyclic loads, had a long fatigue life, and exhibited good low-temperature bending fatigue performance. D1-1 produced cracks at surface defects in the early stage of the test, had an extremely short fatigue life of only 0.012 x 10 6 times, indicating that its performance under low-temperature bending fatigue conditions was poor and it was difficult to meet the durability requirements in actual applications.

[0080] In summary, by comparing the mechanical performance of Example 2 and D1-1 in low-temperature environments, it can be further confirmed that the selection of the composite resin matrix has an important influence on the comprehensive performance of the low-temperature-resistant composite roller blind fabric. The introduction of silicone-modified alkyd resin and epoxy acrylate to form an IPN structure can significantly improve the tensile strength, impact toughness, and bending fatigue performance of the fabric under low-temperature conditions, thereby meeting more extensive application requirements.

[0081] Comparative Example 2: Based on Example 2, only the basalt fiber processing process is modified, and the remaining steps are the same as Example 2. The specific settings are shown in Table 7 below.

[0082] Table 7: Process adjustment comparison table:

[0083]

[0084] The performance test method of the product of the comparative example is completely consistent with Example 1, and the characterization results are shown in Table 8 below.

[0085] Table 8: Performance characterization result comparison table:

[0086] Analyzing the above characterization results, compared with Example 2, the basalt fiber of Comparative Example D2-1 without KH-570 coupling agent treatment and only acid etching, due to the absence of Si-O-Si covalent bonds between the fiber cross-sections, the interfacial bonding relies on physical adsorption, resulting in a significant decline in key performance indicators such as tensile properties, bending strength, and chemical corrosion resistance. Specifically, the tensile strength of D2-1 is only 54.2 MPa, which is much lower than the 85.8 MPa of Example 2, and the elongation at break also decreases to 2.1 %, indicating a significant decrease in strength and toughness of the material when subjected to external forces. The elastic modulus increases to 7.5 GPa, which may mean that the material becomes more rigid and lacks toughness. The bending strength test result is 117.4 MPa, and the bending modulus is 3.6 GPa, although the bending strength value seems close, considering the changes in elongation at break and elastic modulus, it can be inferred that the material's ability to resist external forces during bending deformation has also decreased. The abrasion resistance test shows that the D2-1 abrasion mass is 13.6 mg / 1000 turns, which is slightly lower than the 12.5 mg / 1000 turns of Example 2, but considering the significant decline in tensile properties and bending strength, this small difference is not enough to make up for the overall performance deficiency. In the chemical corrosion resistance test, the tensile strength retention rate of D2-1 after immersion in acidic and alkaline solutions is 57.2 % and 63.4 % respectively, which is much lower than the 92.8 % and 95.3 % of Example 2, indicating that the fabric has poor chemical corrosion resistance and is difficult to maintain stable mechanical properties in harsh environments. These results show that the processing technology of basalt fiber also has an important influence on the mechanical properties of low-temperature resistant composite roller shutter fabric, and the interfacial bonding force between the fiber and the resin matrix can be significantly improved by KH-570 coupling agent treatment, thereby enhancing the overall performance of the fabric.

[0087] In addition, this example and Example 2 were tested for performance, and the specific characterization results are shown in Table 9 below.

[0088] Low temperature tensile test: the composite roller shade fabric prepared by the examples and comparative examples was prepared into 5 groups of standard type I dumbbell test samples with an effective size of 115 mm in length, 50 mm in gauge length, 10 mm in width and 2 mm in thickness, and was stretched at a temperature of -10 ℃ and a stretching rate of 2 mm / min using a universal material testing machine until fracture, and the tensile strength and elongation at break were recorded, and the average value was calculated.

[0089] Low temperature impact toughness test: the composite roller shade fabric prepared by the examples and comparative examples was prepared into 80×10×4mm 3 notched test samples (notch depth 2 mm, radius 0.25 mm), and was tested immediately after immersion in liquid nitrogen to -50 ℃, and was impacted by a pendulum with an energy of 7.5 J, and the impact strength and crack propagation path were measured.

[0090] Low temperature bending fatigue test: the composite roller shade fabric prepared by the examples and comparative examples was prepared into 5 groups of test samples with a length of 80 mm, a width of 10 mm and a thickness of 4 mm, and was subjected to three-point bending cyclic loading (stress ratio R=0.1, frequency 5 Hz) at a temperature of -10 ℃, and the maximum stress was 60% of the room temperature bending strength, and the test was terminated when the sample fractured or the number of cycles reached 10 6 times, and whether cracks appeared in the test samples was observed.

[0091] Table 9: Performance characterization result comparison table

[0092] By analyzing the above characterization data, in the low temperature tensile test, the composite roller shade fabric prepared in Example 2 showed good low temperature adaptability, with a tensile strength of up to 80.6 MPa and an elongation at break of 16.4 %, showing that it could still maintain high strength and toughness under extremely low temperature conditions. In contrast, the tensile strength of D2-1 was only 44.4 MPa, and the elongation at break was also greatly reduced to 1.7 %, indicating that after the KH-570 coupling agent treatment was cancelled, the mechanical properties of the fabric in a low temperature environment were significantly reduced.

[0093] The low temperature impact toughness test results showed that the impact strength of Example 2 was 19.6 kJ / m 2 , the crack propagation rate was 4.5 mm / ms, and no clear cracks were observed during the test, indicating that the fabric had good impact resistance and toughness at low temperatures. The impact strength of D2-1 was only 9.2 kJ / m 2 , the crack propagation rate was as high as 8.3 mm / ms, and cracks rapidly appeared at surface defects, indicating that its low temperature impact toughness was poor, and when only a single physical adsorption existed between the fiber interfaces, damage would easily occur when impacted.

[0094] Low temperature bending fatigue test shows that the composite roller blind fabric of Example 2 still does not appear cracks after experiencing 10 6 times of three-point bending cyclic load, and has a long fatigue life, showing good low temperature bending fatigue performance. While D2-1 produces cracks at the surface defects at the initial stage of the test, and the fatigue life is only 1.2 x 10 6 times, which is much lower than Example 2, indicating that its performance under low temperature bending fatigue conditions is poor and difficult to meet the durability requirements in actual applications.

[0095] Comparative Example 3: Based on Example 2, only the precursor curing process is changed, and the other steps are the same as Example 2. The specific settings are shown in the following Table 10:

[0096] Table 10: Process adjustment comparison table:

[0097]

[0098] The performance test method of the product of the comparative example is completely consistent with Example 1, and the characterization results are shown in the following Table 11.

[0099] Table 11: Performance characterization result comparison table:

[0100] Analyzing the above characterization results, compared with Example 2, the precursor curing process of Comparative Example D3-1 is changed to a single stage, and is cured at a pressure of 0.8 MPa and a temperature of 120 ℃ for 80 min. The tensile properties, bending strength and chemical corrosion resistance are all reduced, but the reduction is less than that of Comparative Examples D1-1 and D2-1. Specifically, the tensile strength of D3-1 is 73.4 MPa, which is lower than the 85.8 MPa of Example 2, but still remains at a high level, the elongation at break is 12.1 %, which is lower than the 18.1 % of Example 2, but still has certain toughness. The elastic modulus changes little, which is 4.5 GPa, indicating that the material maintains a certain balance between rigidity and toughness. The bending strength test result is 105.4 MPa, and the bending modulus is 4.2 GPa, which is lower than Example 2, but still meets certain mechanical requirements. The abrasion resistance test shows that the D3-1 abrasion mass is 18.6 mg / 1000 turns, which is higher than the 12.5 mg / 1000 turns of Example 2, but lower than D1-1 and D2-1, indicating that its abrasion resistance is relatively good. In the chemical corrosion resistance test, the tensile strength retention rate of D3-1 after immersion in acidic and alkaline solutions is 85.3 % and 89.4 % respectively, which is lower than Example 2, but much higher than D1-1 and D2-1, indicating that its mechanical properties in harsh environments are relatively stable.

[0101] In addition, performance tests were performed on the above examples and the example 2, and the specific characterization results are shown in Table 12 below.

[0102] Low-temperature tensile test: the composite roller blind fabric prepared in the examples and the comparative examples was prepared into 5 groups of standard I-shaped dumbbell test samples with an effective size of 115 mm in length, 50 mm in gauge length, 10 mm in width, and 2 mm in thickness. The tensile test was performed at a temperature of-10℃ and a tensile rate of 2 mm / min using a universal material testing machine until fracture, and the tensile strength and elongation at break were recorded and the average value was calculated.

[0103] Low-temperature impact toughness test: the composite roller blind fabric prepared in the examples and the comparative examples was prepared into 80x10x4mm 3 Notched test sample (notch depth 2 mm, radius 0.25 mm), liquid nitrogen immersion to-50℃ immediately after testing, pendulum impact with an energy of 7.5 J, measuring impact strength and crack propagation path.

[0104] Low-temperature bending fatigue test: the composite roller blind fabric prepared in the examples and the comparative examples was prepared into 5 groups of test samples with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm. The three-point bending cyclic load was used at a temperature of-10℃ (stress ratio R=0.1, frequency 5 Hz), the maximum stress was 60% of the room temperature bending strength, and the test was terminated when the sample was broken or the cycle number reached 10 6 times, and whether cracks appeared in the test sample was observed.

[0105] Table 12: Performance characterization result comparison table

[0106] Analysis of the above characterization data shows that in the low-temperature tensile test, the tensile properties of the comparative example D3-1 significantly decreased after the precursor curing process was changed to a single stage, the tensile strength was only 28.6 MPa, and the elongation at break was reduced to 5.32%, indicating that the mechanical properties of the material were greatly weakened at low temperature. The low-temperature impact toughness test results show that the impact strength of D3-1 is greatly reduced to 9.9 kJ / m 2 , the crack propagation rate is sharply increased to 15.1 mm / ms, and cracks are rapidly generated at the surface defects and fiber interfaces, indicating that the low-temperature impact toughness is poor and the material is prone to damage when impacted. D3-1 generates cracks at the surface defects and fiber interfaces at the beginning of the low-temperature impact toughness test, and the fatigue life is extremely short, only 0.033x10 6 times, which is much lower than that of example 2, and it is difficult to meet the durability requirements in actual applications. Combined with the detection data of comparative example 3 at room temperature, the gradient curing of the present application can significantly improve the interface integrity and structural uniformity through staged reaction control, and effectively eliminate the residual stress existing in the material.

[0107] Comparative Example 4: In this example, the polyurethane system was toughened using a commercially available low-temperature-resistant roller shutter mainstream solution. The specific settings are shown in Table 13 below.

[0108] Table 13: Process adjustment comparison table:

[0109]

[0110] The performance test method of the comparative product was completely consistent with Example 1, and the characterization results are shown in Table 14 below.

[0111] Table 14: Performance characterization results comparison table:

[0112] Analyzing the above characterization results, compared with Example 2, the tensile properties, bending strength and chemical corrosion resistance of Comparative Example D4-1, which used a commercially available low-temperature-resistant roller shutter mainstream solution to toughen the polyurethane system, all decreased significantly. Specifically, the tensile strength of D4-1 was only 48.3 MPa, which was much lower than the 85.8 MPa of Example 2. Although the elongation at break increased to 25.6 %, considering the significant decrease in tensile strength, this change was not conducive to the overall mechanical properties of the material. The elastic modulus decreased significantly to 2.1 GPa, indicating that the material became softer, possibly sacrificing some rigidity. The bending strength test result was 60.5 MPa, and the bending modulus was 1.9 GPa, which was also much lower than Example 2, indicating that the fabric's ability to resist bending deformation decreased significantly. The abrasion resistance test showed that the D4-1 abrasion mass was 42.5 mg / 1000 turns, which was much higher than the 12.5 mg / 1000 turns of Example 2, indicating that its abrasion resistance was poor. In the chemical corrosion resistance test, the tensile strength retention rate of D4-1 after immersion in acidic and alkaline solutions was 65.5 % and 72.3 % respectively, which was much lower than the 92.8 % and 95.3 % of Example 2, indicating that the fabric had poor chemical corrosion resistance and was difficult to maintain stable mechanical properties in harsh environments. These results show that although toughening the polyurethane system can increase the elongation at break of the material to some extent, it will sacrifice its tensile strength, bending strength, abrasion resistance and chemical corrosion resistance, making it difficult to meet the comprehensive performance requirements in actual applications.

[0113] In addition, this example was tested for performance together with Example 2, and the specific characterization results are shown in Table 15 below.

[0114] Low temperature tensile test: the composite roller blind fabric prepared by the examples and the comparative examples was prepared into 5 groups of standard type I dumbbell test samples with an effective size of 115 mm in length, 50 mm in gauge length, 10 mm in width and 2 mm in thickness, and was stretched using a universal material testing machine at a temperature of -10 ℃ and a stretching rate of 2 mm / min until fracture, and the tensile strength and elongation at break were recorded, and the average value was calculated.

[0115] Low temperature impact toughness test: the composite roller blind fabric prepared by the examples and the comparative examples was prepared into 80×10×4 mm 3 notched test samples (notch depth 2 mm, radius 0.25 mm), and was tested immediately after immersion in liquid nitrogen to -50 ℃, and was impacted with a pendulum with an energy of 7.5 J, and the impact strength and crack propagation path were measured.

[0116] Low temperature bending fatigue test: the composite roller blind fabric prepared by the examples and the comparative examples was prepared into 5 groups of test samples with a length of 80 mm, a width of 10 mm and a thickness of 4 mm, and was subjected to three-point bending cyclic loading (stress ratio R=0.1, frequency 5 Hz) at a temperature of -10 ℃, and the maximum stress was 60% of the room temperature bending strength, and the test was terminated when the sample fractured or the number of cycles reached 10 6 times, and whether cracks appeared in the test samples was observed.

[0117] Table 15: Performance characterization result comparison table

[0118] By analyzing the above characterization data, in the low temperature tensile test, the tensile strength of the comparative example D4-1 was only 25.3 MPa, which was much lower than the 80.6 MPa of example 2, and the elongation at break was also reduced to 8.1 %, showing that the mechanical properties of the material were greatly weakened under extremely low temperature conditions. Further observation showed that the plasticizer (DOP) in the comparative example D4-1 crystallized and precipitated at -50 ℃, forming a stress concentration point and causing early fracture. The low temperature impact toughness test results showed that the impact strength of D4-1 was greatly reduced to 2.8 kJ / m 2 , the crack propagation rate increased sharply to 15.3 mm / ms, and cracks rapidly appeared at surface defects, indicating that the low temperature impact toughness was very poor and the material was prone to damage when impacted. In the low temperature bending fatigue test, the fatigue life of D4-1 was extremely short, only 0.085×10 6 times, which was much lower than the 2.1×10 6Secondly, it shows that its performance is very poor under low temperature bending fatigue conditions, and it is difficult to meet the durability requirements in practical applications. Further observation found that the plasticizer in the comparative material crystallizes and migrates at low temperature, forming holes and becoming fatigue crack sources. These results show that although the use of commercially available low-temperature-resistant roller shutter mainstream solutions to toughen the polyurethane system can improve some properties of the material to some extent, it will greatly sacrifice its low-temperature tensile strength, low-temperature impact toughness and low-temperature bending fatigue performance, making it difficult to meet the comprehensive performance requirements in practical applications.

Claims

1. A method for preparing a low-temperature-resistant composite roller shutter fabric, characterized in that the method comprises: 1) pretreating basalt fibers to produce functionalized fibers; 2) mixing a composite resin matrix with the functionalized fibers to produce a prepreg; 3) coating the prepreg on a substrate surface and hot-pressing to produce a precursor; 4) gradient curing the precursor to produce the low-temperature-resistant composite roller shutter fabric; the pretreatment in step 1) is performed using silane coupling agent KH-570; the composite resin matrix in step 2) is composed of epoxy acrylate and silicone-modified alkyd resin mixed and compounded; the hot-pressing conditions in step 3) include first-stage processing and second-stage processing, specifically: first-stage processing is controlled at a pressure of 0.3-0.5 MPa and a temperature of 80-90 ℃ for 5-8 min; second-stage processing is controlled at a pressure of 1.0-1.2 MPa and a temperature of 100-110 ℃ for 10-15 min; the gradient curing in step 4) includes: a pre-curing stage: maintaining at a temperature of 60-80 ℃ and a pressure of 0.5-0.8 MPa for 20-30 min; a main curing stage: maintaining at a temperature of 120-130 ℃ in a nitrogen atmosphere for 40-50 min, with 0.5-1.0 Phr of dicumyl peroxide added during the process; a post-curing stage: maintaining at a temperature of 150-160 ℃ under a vacuum degree of ≤-0.09 MPa for 15-20 min.

2. The method for preparing a low-temperature-resistant composite roller shutter fabric according to claim 1, characterized in that the pretreatment in step 1) is performed as follows: etching the fiber surface with a hydrochloric acid solution with a mass concentration of 55-60 % for 30-45 min, filtering, and then placing in a silane coupling agent KH-570 aqueous solution with a concentration of 1-2 wt %, ultrasonic treatment at a temperature of 60-80 ℃ for 20-30 min, and filtering and drying to a water content of <0.5 %.

3. The method for preparing a low-temperature-resistant composite roller shutter fabric according to claim 1, characterized in that the composite resin matrix in step 2) is mixed and compounded by mixing epoxy acrylate and silicone-modified alkyd resin at a mass ratio of (3-3.5):1 under the conditions of a rotation speed of 40-60 rpm and a temperature of 80-100 ℃ for 30-40 min; the epoxy acrylate has an epoxy equivalent weight of 180-220 g / eq; the silicone-modified alkyd resin has a hydroxyl value of 50-70 mg KOH / g.

4. The method for preparing a low-temperature-resistant composite roller shutter fabric according to claim 1, characterized in that the functionalized fibers are added in an amount of 20-30 wt % and dispersed under the conditions of a vacuum degree of ≤-0.08 MPa and a shear rate of 2000-2500 rpm for 15-20 min.

5. The method for preparing a low-temperature-resistant composite roller shutter fabric according to claim 1, characterized in that ​ ​ ​ Step 3) the substrate is plain weave glass fiber cloth with a thickness of 0.23-0.27 mm; Step 3) the coating process adopts knife coating, and double-sided coating is carried out at a temperature of 60-70 ℃, a coating speed of 24 m / min, a coating gap of 0.5-0.8 mm, and a coating thickness of 0.12-0.14 mm.

6. A low-temperature-resistant composite roller shade fabric prepared by any of the methods in claims 1-5.

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