Wear-resistant heat-insulating Z-direction reinforced laminated composite material and preparation method thereof

Abstract

The invention belongs to the technical field of textile fabrics, and provides a wear-resistant heat-insulating Z-direction reinforced laminated composite material which comprises coating layers, a core layer and a Z-direction reinforced material, the coating layers are aramid paper, the core layer is silicon dioxide fiber / aramid fiber mesh cloth composite felt, the Z-direction reinforced material is aramid fiber, the core layer is located between the two coating layers to form a'sandwich 'laminated structure, and the Z-direction reinforced material is a composite material. The Z-direction reinforcing material penetrates through the coating layer and the core layer in the thickness direction; the composite material is prepared by the following steps: preparing a silicon dioxide fiber / aramid fiber screen cloth composite felt as a core layer through a wet forming process, then carrying out surface treatment on one side, in contact with the core layer, of each coating layer by utilizing air radio frequency plasma, placing the core layer between the two coating layers, vertically penetrating a Z-direction reinforcing material through the coating layers and the core layer, and carrying out heat treatment on the Z-direction reinforcing material to obtain the composite material. And two ends are flush with the upper and lower surfaces of the composite material. The composite material has better wear resistance and heat insulation performance.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a Z-direction reinforced silicon oxide nanofiber / aramid mesh laminate composite material and a preparation method thereof. Background Art

[0002] Traditional SiO2 fibers are relatively thick in diameter, brittle, and have poor mechanical properties, which greatly limits their application. As a new type of nano-ceramic fiber material, SiO2 nanofibers overcome the disadvantage of brittleness and have the advantages of high temperature resistance, fire resistance, and chemical stability. The products have the characteristics of low density, high temperature resistance, low thermal conductivity, and mechanical vibration resistance, and can be used in aerospace, industrial metallurgy, construction, mechanical chemical industry and other fields.

[0003] The porous structure of SiO2 nanofibers with ultra-high porosity gives them excellent thermal insulation properties, but their fragile three-dimensional network structure makes it difficult to keep the connection between particles intact during processing. They are difficult to shape and are not wear-resistant. Other reinforcements need to be added to make composite materials to compensate for their insufficient mechanical properties.

[0004] In view of the problems of silica nanofibers being difficult to felt, having poor strength, and decreasing thermal insulation after contact with water, the silica nanofiber / aramid mesh composite felt was prepared using a non-woven wet forming process with aramid mesh as the reinforcement skeleton. After the felt was formed, it was hydrophobicized with an organic silicone solution to maintain the stability of the performance. The composite felt has the high strength of aramid mesh and excellent thermal insulation performance, but the mass loss rate after 100 frictions is ≥26%, and the wear resistance affects the application of the material, which needs to be further improved. Summary of the invention

[0005] In view of the problems in the prior art, the present invention designs a Z-direction reinforced laminated composite material, and establishes an array-type Z-direction reinforced "sandwich" composite structure based on the silica / aramid mesh composite felt. Smooth, lightweight and wear-resistant aramid paper is coated on the upper and lower parts of the composite felt, and high-strength aramid 1414 yarn is used to construct reinforcing ribs in the Z direction to enhance the connection strength between the composite materials. Based on the aramid mesh structural unit, an array-type Z-direction reinforced structure is established to improve the wear resistance and thermal insulation properties of the composite material.

[0006] In order to achieve the above technical objectives, the present invention provides a wear-resistant heat-insulating Z-direction reinforced laminated composite material, which at least includes a cladding layer, a core layer and a Z-direction reinforcing material;

[0007] The coating layer is aramid paper, the core layer is silica fiber / aramid mesh composite felt, and the Z-direction reinforcement material is aramid fiber;

[0008] The core layer is located between two cladding layers to form a "sandwich" laminate structure;

[0009] The Z-direction reinforcement material passes through the cladding layer and the core layer along the thickness direction.

[0010] In some technical solutions of the present invention, the coating layer is made of aramid 1313 and / or aramid 1414, and the aramid paper prepared with the fiber material is light, thin and wear-resistant.

[0011] In some technical solutions of the present invention, the coating layer has a thickness of 0.05-0.08 mm and a surface density of 40-50 g / m 2 .

[0012] In some technical solutions of the present invention, the sum of the thicknesses of the coating layers is less than 3% of the thickness of the composite felt.

[0013] In some technical solutions of the present invention, the silica fiber / aramid mesh composite felt comprises silica nanofibers, aramid mesh, and a hydrophobic agent, and is formed into a felt by a non-woven wet process. The composite felt formed by the non-woven wet process not only retains the superior characteristics of silica nanofibers such as light weight, low thermal conductivity, and high temperature resistance, but also has high overall strength and good formability due to the skeleton structure of the aramid mesh, and has excellent fire resistance and heat insulation properties.

[0014] In some technical solutions of the present invention, the hydrophobic agent is selected from silicone, and is further preferably selected from hydrogen-containing silicone oil BS5130. The composite felt is hydrophobically finished with a hydrophobic agent, and a hydrophobic film can be formed on the surface of the fabric, which effectively improves the hydrophobicity of the fabric. At the same time, in the hydrophobic treatment film-forming stage, the composite felt surface treated with silicone solution forms a film, which has an inhibitory effect on the diffusion of heat, and with the increase of silicone, the combustion performance of the composite felt gradually decreases.

[0015] In some technical solutions of the present invention, the Z-direction reinforcing material is selected from aramid 1313 yarn and / or aramid 1414 yarn. Further, the linear density of the Z-direction reinforcing material is 150D-220D strands.

[0016] In some technical solutions of the present invention, the Z-direction reinforcing yarn is based on the basic unit of the surface grid of the wrapping layer, vertically passes through the wrapping layer and the core layer to establish a reinforcing structure.

[0017] In some technical solutions of the present invention, a Z-direction reinforcement structure is established every 0-3 grids in the transverse and longitudinal grids of the wrapping layer.

[0018] Furthermore, a Z-direction reinforcement structure is established in adjacent grids of the wrapping layer to form a 1×1 array element.

[0019] Furthermore, a Z-direction reinforcement structure is established in every two grids in the transverse and longitudinal directions of the wrapping layer to form a 2×2 array element.

[0020] Furthermore, a Z-direction reinforcement structure is established in every three grids in the transverse and longitudinal directions of the wrapping layer to form a 3×3 array element.

[0021] Furthermore, a Z-direction reinforcement structure is established in every four grids in the transverse and longitudinal directions of the wrapping layer to form a 4×4 array element.

[0022] After the Z-direction reinforcement structure is established, the smaller the distance between the array elements and the more array elements per unit area, the higher the interlayer bonding strength of the composite material is, but the surface roughness Ra of the composite material increases, the friction force F becomes larger, and the mass loss rate increases; at the same time, the increase in the Z-direction reinforcement structure strengthens the Z-direction material strength of the composite material, making the fabric layer and layer structure more solid, and reducing the friction loss between the surfaces. The composite material with 2×2 array elements has a stronger interlayer structure bonding strength, and the friction of the yarn during the friction process causes less damage to the felt body, so the mass loss rate is minimal.

[0023] In addition, the composite material after Z-direction reinforcement accommodates more air retention, better hinders the heat transfer between fabrics, reduces the temperature rise rate on the back of the composite felt, enhances the thermal insulation protection ability, reduces the thermal conductivity of the fabric, and increases the thermal insulation performance. With the increase of the number of array elements, the Z-direction reinforcement leads to s Slightly increase, porosity φ increases, solid phase thermal conductivity (1-φ)λ s The thermal conductivity of the composite material is the lowest when the solid phase thermal conductivity decreases and the gas phase thermal conductivity increases.

[0024] The present invention also provides a method for preparing a wear-resistant and heat-insulating Z-direction reinforced laminated composite material, which comprises at least the following steps:

[0025] Step 1: preparing a silica fiber / aramid mesh composite felt as a core layer through a wet forming process;

[0026] Step 2: Surface treatment is performed on the contact side of the cladding layer and the core layer by using air radio frequency plasma;

[0027] Step 3: Place the core layer between the two covering layers, use the Z-direction reinforcement material to vertically pass through the covering layer and the core layer, and make the two ends flush with the upper and lower surfaces of the composite material.

[0028] In some technical solutions of the present invention, the preparation process of the silica fiber / aramid mesh composite felt in step 1 includes at least three steps: slurry preparation, felt body molding, and hydrophobic treatment.

[0029] Preferably, the slurry preparation step at least includes: adding water and silica nanofibers in a ratio of (190-210):1 in a pulper, stirring at a speed of 450-550 rpm, and a pulping time of 4-6 minutes to prepare a short fiber slurry.

[0030] Furthermore, the slurry concentration is 0.5-0.7wt%.

[0031] Preferably, the felt body forming step includes: fixing the aramid mesh cloth on the filter net of the paper sheet former, adding the prepared short fiber slurry into the pulp pool at a flow rate of 70-90L / min, stirring with air blowing for 14-16s, draining water quickly for 28-32s and then vacuum pumping for 55-65s, and putting the wet composite felt that has been negatively pressure-formed into a 110-130°C oven for drying.

[0032] Preferably, the water treatment step comprises: mixing deionized water and a hydrophobic agent at room temperature to form a solution with a concentration of 0.5-1.0wt%, placing the dried composite felt in the solution to completely saturate it, and drying it at a temperature of 170-190°C to obtain a hydrophobic treated composite felt. Furthermore, the surface density of the composite felt is 350-400g / m 2 , thickness 1.5-2mm.

[0033] In some technical solutions of the present invention, the radio frequency power of the air radio frequency plasma is 200-220W, and the processing time is 10-30min.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The present invention establishes a "Z-direction reinforced sandwich" composite material structure. The upper and lower layers of the composite felt are provided with a coating layer, and a high-strength Z-direction reinforcing material is used to construct reinforcing ribs to enhance the connection strength between the composite materials, thereby forming a Z-direction reinforced structure.

[0036] 2. The wear resistance of the composite material with different array element numbers Z-direction reinforcement structure is significantly improved, and the mass loss rate after 8000 friction cycles is less than 1.5%. Among them, the mass loss rate of the composite material with 2×2 array elements is the lowest, which is only 0.77%.

[0037] 3. The thermal conductivity of the "Z-direction reinforced sandwich" composite material structure established by the present invention can be reduced to below 0.06W / (m·K). On the one hand, the continuous convection air layer between the cladding layer and the core layer is split into multiple regions by the Z-direction reinforcing yarn, breaking the original strong convection process, inhibiting air convection heat transfer, resulting in a decrease in gas phase thermal conductivity, an increase in yarn content, and an overall decrease in the thermal conductivity of the composite material; on the other hand, with the increase in the number of array elements, the Z-direction reinforcement leads to a decrease in the thermal conductivity of the composite material. s Slightly increase, porosity φ increases, solid phase thermal conductivity (1-φ)λ s The thermal conductivity of the composite material reaches its minimum when the decrease of solid-phase thermal conductivity and the increase of gas-phase thermal conductivity reach a balance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 It is a schematic diagram of the composite material structure of the "Z-direction reinforced sandwich" of the present invention;

[0040] Figure 2 Schematic diagram of array element distribution in some embodiments of the present invention. DETAILED DESCRIPTION

[0041] The following is a clear and complete description of the technical solutions in the present invention in conjunction with the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Preparation of core composite felt:

[0043] Slurry preparation: Add 200:1.2 water and silicon oxide nanofibers in a pulping machine, stir at 500 rpm, and beat for 5 min to prepare a short fiber slurry with a concentration of 0.6%;

[0044] Composite felt forming: fix the aramid mesh cloth on the filter screen of the paper sheet former, add the prepared slurry into the slurry pool at a flow rate of 80L / min, blow and stir for 15 seconds, quickly drain for 30 seconds, and then vacuum pump for 60 seconds, put the wet composite felt that has been negatively pressure-set into a 120°C oven for drying to obtain a composite felt;

[0045] Hydrophobic treatment: at room temperature, deionized water and BS5130 hydrophobic agent were mixed into a solution with a concentration of 0.5wt%. The dried composite felt was placed in the solution to make the composite felt completely soaked, and then dried at 180°C to obtain a core layer composite felt with a surface density of 362g / m 2 , thickness: 1.68mm.

[0046] Example 1

[0047] A Z-direction reinforced laminated composite material with a thickness of 0.05 mm and a surface density of 40 g / m 2The NOMEX T410 aramid paper was treated with plasma, the radio frequency power was 200W, and the treatment time was 30 minutes; the core layer composite felt was placed between two layers of aramid paper, and 200D / 3 aramid 1414 yarn was used as the Z-direction reinforcement yarn to establish a Z-direction reinforcement structure with an array element number of 1×1.

[0048] Example 2

[0049] A Z-direction reinforced laminated composite material with a thickness of 0.05 mm and a surface density of 40 g / m 2 The NOMEX T410 aramid paper was treated with plasma, the radio frequency power was 200W, and the treatment time was 30 minutes; the core layer composite felt was placed between two layers of aramid paper, and 200D / 3 aramid 1414 yarn was used as the Z-direction reinforcement yarn to establish a Z-direction reinforcement structure with an array element number of 2×2.

[0050] Example 3

[0051] A Z-direction reinforced laminated composite material with a thickness of 0.05 mm and a surface density of 40 g / m 2 The NOMEX T410 aramid paper was treated with plasma, the radio frequency power was 200W, and the treatment time was 30 minutes; the core layer composite felt was placed between two layers of aramid paper, and 200D / 3 aramid 1414 yarn was used as the Z-direction reinforcement yarn to establish a Z-direction reinforcement structure with an array element number of 3×3.

[0052] Example 4

[0053] A Z-direction reinforced laminated composite material with a thickness of 0.05 mm and a surface density of 40 g / m 2 The NOMEX T410 aramid paper was treated with plasma, the radio frequency power was 200W, and the treatment time was 30 minutes; the core layer composite felt was placed between two layers of aramid paper, and 200D / 3 aramid 1414 yarn was used as the Z-direction reinforcement yarn to establish a Z-direction reinforcement structure with an array element number of 4×4.

[0054] Comparative Example 1: The difference from Example 1 is that only the core layer composite felt

[0055] Test experiment:

[0056] 1. Abrasion resistance test: Refer to the standard "GB / T 21196.1-2007 Determination of abrasion resistance of textile fabrics by Martindale method" to test the mass loss after 8000 laps of friction. The calculation formula is as follows:

[0057]

[0058] In formula (1), W is the mass loss rate of the sample, %; m0 is the mass of the sample before friction, g; m' is the mass of the sample after a certain number of friction turns, g

[0059] 2. Thermal insulation test:

[0060] 2.1 Thermal conductivity test: The thermal conductivity of the sample was tested using a thermal conductivity tester in accordance with the standard "GB / T 10297-2015 Hot wire method for determination of thermal conductivity of non-metallic solid materials". Each sample was tested 5 times and the average value was taken.

[0061] 2.2 Thermal insulation performance test: The constant temperature heating table is set at 60°C, and each sample is cut into 5×5cm 2 The sample was placed on a constant temperature platform, and the surface temperature changes of the embodiment and the comparative example within 5 minutes were recorded with a thermometer. Four samples were tested and the average value was taken, and the thermal insulation efficiency was calculated by the surface temperature:

[0062]

[0063] In formula (4), T is the thermal insulation efficiency; t is the surface temperature.

[0064] The performance test results are shown in Table 1:

[0065] Table 1 Test results of wear resistance and thermal insulation performance of composite materials

[0066]

[0067] The results show that the wear resistance of the composite materials with Z-direction reinforcement structures with different numbers of array elements prepared in Examples 1-4 is significantly improved, and the mass loss after 8000 friction circles can be less than 1.5%; the thermal conductivity and thermal insulation efficiency of the composite materials with Z-direction reinforcement structures with different numbers of array elements prepared in the examples are significantly improved compared with the control example.

[0068] Finally, a few points should be explained: Although the present invention has been described in detail above with general descriptions and specific embodiments, on the basis of the present invention, the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that: it is still possible to modify the technical solutions recorded in the aforementioned embodiments, or to replace part or all of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present invention.

Claims

1. A wear-resistant and heat-insulating Z-direction reinforced laminated composite material, characterized in that: At least comprising a cladding layer, a core layer and a Z-direction reinforcement material; The coating layer is aramid paper, the core layer is silica fiber / aramid mesh composite felt, and the Z-direction reinforcement material is aramid fiber; The core layer is located between two cladding layers to form a "sandwich" laminate structure; The Z-direction reinforcement material passes through the cladding layer and the core layer along the thickness direction.

2. The Z-direction reinforced laminate composite material according to claim 1, characterized in that: The coating layer is made of aramid 1313 and / or aramid 1414, with a thickness of 0.05-0.08 mm and a surface density of 40-50 g / m 2 .

3. The Z-direction reinforced laminate composite material according to claim 1, characterized in that: The sum of the thickness of the coating layers is less than 3% of the thickness of the composite felt.

4. The Z-direction reinforced laminate composite material according to claim 1, characterized in that: The silica fiber / aramid mesh composite felt comprises silica nanofibers, aramid mesh and a hydrophobic agent and is felted by a non-woven wet method.

5. The Z-direction reinforced laminate composite material according to claim 1, characterized in that: The hydrophobic agent is selected from silicone.

6. The Z-direction reinforced laminate composite material according to claim 1, characterized in that: The Z-direction reinforcing yarn is based on the basic unit of the surface grid of the wrapping layer, vertically passes through the wrapping layer and the core layer to establish a reinforcing structure.

7. The Z-direction reinforced laminate composite material according to claim 1, characterized in that: A Z-direction reinforcing structure is established every 0-4 grids in the transverse and longitudinal grids of the wrapping layer.

8. A method for preparing a Z-direction reinforced laminated composite material, characterized in that: The method comprises at least the following steps: Step 1: preparing silica fiber / aramid mesh composite felt as a core layer by a wet forming process; Step 2: performing surface treatment on the covering layer by using air radio frequency plasma; Step 3: placing the core layer between the two covering layers, vertically passing the covering layer and the core layer with a Z-direction reinforcement material, and trimming the two ends flush with the upper and lower surfaces of the composite material.

9. The method for preparing a composite material according to claim 8, characterized in that: The preparation process of the silica fiber / aramid mesh composite felt in step 1 at least includes three steps: slurry preparation, felt body molding, and hydrophobic treatment.

10. The method for preparing a composite material according to claim 8, characterized in that: The radio frequency power of the air radio frequency plasma is 200-220W, and the processing time is 10-30min.

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