Automobile exhaust pipe heat insulation cover material and preparation method thereof

Abstract

The invention provides a heat shield material for automobile exhaust pipe and a preparation method thereof, and relates to the technical field of heat shield materials. The material is prepared from the following raw materials by weight: 25-35 parts of hyperbranched polyborosilazane containing benzene ring, 20-30 parts of reinforcing material, 8-12 parts of ceramic filler, 3-5 parts of coupling agent, 20-30 parts of fluorosilicone type thermoplastic polyurethane elastomer containing benzene ring, 1-3 parts of 1-isopropenyl-2-benzimidazolone, 1-3 parts of diphenyl (4-vinylphenyl) phosphine oxide, 2-4 parts of 2,4,6-trivinyl cycloboroxane, 3-6 parts of 2-acrylamide-2-methylpropane sulfonic acid, 0.8-1.5 parts of phosphorus pentoxide, 0.5-0.8 parts of polyphosphoric acid, and 0.1-0.3 parts of curing agent. The material has good flame retardant and fireproof properties, high temperature resistance and weather resistance, and long service life.

Description

Technical Field

[0001] The invention relates to the technical field of heat insulation cover materials, and in particular to a heat insulation cover material for an automobile exhaust pipe and a preparation method thereof. Background Art

[0002] The automobile exhaust pipe is an important part of the automobile engine exhaust system. In the process of exhaust gas discharge, the exhaust pipe contains a lot of heat. Due to the circulation of heat, the temperature of the exhaust pipe is extremely high. It is necessary to use a heat shield to protect it to reduce its impact on the performance and life of surrounding components. At present, the common heat shield insulation materials mainly include metal aluminum plates, asbestos cloth, glass fiber cloth, etc. However, these materials have some disadvantages. For example, although aluminum materials have good insulation effects, the production cost is relatively high and the elongation is limited. Asbestos cloth and glass fiber cloth have the disadvantages of short service life, easy damage, not environmentally friendly, and need frequent replacement and maintenance.

[0003] In order to solve the above problems, the Chinese invention patent with the authorization announcement number CN106589795B discloses a method for preparing a basalt fiber engine hood, which involves the field of thermal insulation materials. The steps include mixing, pressing, trimming, coating and packaging, wherein the specific weight components of the raw materials are 20-50% of the base agent, 30-70% of the reinforcing material, 5-10% of the curing agent, 0.5-5% of the accelerator, 0.5-2% of the release agent, and 15-30% of the filler; the invention solves the shortcomings of the engine hood prepared by the fiber of the common thermal insulation material, such as short life, easy damage, not environmentally friendly, and frequent replacement and maintenance, and discloses a more efficient method for preparing the engine hood. However, the high temperature resistance and weather resistance of the thermal insulation hood material still need to be further improved.

[0004] Therefore, the development of an automobile exhaust pipe heat insulation cover material with good flame retardancy, high temperature resistance and weather resistance, and long service life and a preparation method thereof meets market demand, has broad market value and application prospects, and is of great significance to promoting the development of the heat insulation cover material field. Summary of the invention

[0005] In view of the above problems, the object of the present invention is to provide an automobile exhaust pipe heat insulation cover material with good flame retardancy, high temperature resistance and weather resistance, and long service life, and a preparation method thereof.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a kind of automobile exhaust pipe heat insulation cover material is made of the following raw materials in parts by weight: 25-35 parts of hyperbranched polyborosilazane containing benzene ring, 20-30 parts of reinforcing material, 8-12 parts of ceramic filler, 3-5 parts of coupling agent, 20-30 parts of fluorosilicone type thermoplastic polyurethane elastomer containing benzene ring, 1-3 parts of 1-isopropenyl-2-benzimidazolone, 1-3 parts of diphenyl (4-vinylphenyl) phosphine oxide, 2-4 parts of 2,4,6-trivinyl cycloboroxane, 3-6 parts of 2-acrylamido-2-methylpropane sulfonic acid, 0.8-1.5 parts of phosphorus pentoxide, 0.5-0.8 parts of polyphosphoric acid, and 0.1-0.3 parts of curing agent.

[0007] Preferably, there is no special requirement for the source of the benzene ring-containing hyperbranched polyborosilazane. In one embodiment of the present invention, the benzene ring-containing hyperbranched polyborosilazane is prepared according to the method in the Chinese invention patent with application announcement number CN117024144A.

[0008] Preferably, the reinforcing material is any one of basalt fiber, carbon fiber and boron fiber.

[0009] Preferably, the average diameter of the reinforcing fibers is 3-9 μm, and the aspect ratio is (20-30):1.

[0010] Preferably, the ceramic filler is at least one of mica powder, talc powder and wollastonite powder; and the particle size of the ceramic filler is 1000-2000 mesh.

[0011] Preferably, the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

[0012] Preferably, there is no special requirement for the source of the fluorosilicone thermoplastic polyurethane elastomer containing benzene rings. In one embodiment of the present invention, the fluorosilicone thermoplastic polyurethane elastomer containing benzene rings is prepared according to the method in Example 6 of the authorization announcement number CN111154064B.

[0013] Preferably, the curing agent is a mixture of dicumyl peroxide DCP, dodecyl peroxide LPO and azobisisoheptonitrile ABVN in a mass ratio of (1-3):(0.8-1.2):1.

[0014] Another object of the present invention is to provide a method for preparing the automobile exhaust pipe heat insulation cover material, comprising the following steps: mixing the raw materials evenly by weight, loading them into a molding mold at 140-160°C, molding them according to a step-by-step temperature increase molding process, and obtaining the automobile exhaust pipe heat insulation cover material after pressure relief and demolding.

[0015] Preferably, the step-by-step temperature-increasing molding process is as follows: heating to 110-130°C and keeping warm for 0.8-1.2 hours, during which no axial pressure is applied; then heating to 145-155°C and keeping warm for 1.5-2.5 hours, while applying an axial pressure of 15-32 MPa, which is the molding pressure; keeping the molding pressure unchanged, heating to 175-185°C and keeping warm for 1-2 hours, and finally heating to 190-220°C and keeping warm for 0.8-1.2 hours.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The preparation method of the automobile exhaust pipe heat insulation cover material disclosed in the present invention has simple process, convenient operation and control, high preparation efficiency and finished product qualification rate, low energy consumption, low dependence on equipment, which is conducive to saving labor costs, suitable for large-scale production, strong practicality, and high promotion and application value.

[0018] (2) The automobile exhaust pipe heat insulation cover material disclosed in the present invention is made of the following raw materials in parts by weight: 25-35 parts of benzene ring-containing hyperbranched polyborosilazane, 20-30 parts of reinforcing material, 8-12 parts of ceramic filler, 3-5 parts of coupling agent, 20-30 parts of fluorosilicone type thermoplastic polyurethane elastomer containing benzene ring, 1-3 parts of 1-isopropenyl-2-benzimidazolone, 1-3 parts of diphenyl (4-vinylphenyl) phosphine oxide, 2-4 parts of 2,4,6-trivinyl cycloboroxane, 3-6 parts of 2-acrylamido-2-methylpropanesulfonic acid, 0.8-1.5 parts of phosphorus pentoxide, 0.5-0.8 parts of polyphosphoric acid, and 0.1-0.3 parts of curing agent. Through the mutual cooperation and joint action of the raw materials, the automobile exhaust pipe heat insulation cover material prepared has good flame retardant and fireproof properties, high temperature resistance and weather resistance, and long service life. The sulfonic acid group on 2-acrylamido-2-methylpropane sulfonic acid can react chemically with raw materials containing benzene rings under the catalysis of phosphorus pentoxide and polyphosphoric acid. At the same time, raw materials containing unsaturated olefin bonds can also undergo copolymerization and curing reaction under the action of initiators to form an interpenetrating network structure, which can effectively improve flame retardancy, high temperature resistance and weather resistance, thereby extending its service life.

[0019] (3) The automobile exhaust pipe heat insulation cover material disclosed in the present invention introduces hyperbranched polyborosilazane, fluorosilicone thermoplastic polyurethane elastomer, benzimidazolone, phenylphosphine oxide, and cycloboroxine structures into the molecular structure of the heat insulation cover material by rationally selecting the types and amounts of raw materials. These structures, under the multiple effects of electronic effect, steric effect, and conjugation effect, make the product have better flame retardant and fireproof properties, and better high temperature resistance and weather resistance.

[0020] (4) The automobile exhaust pipe heat insulation cover material disclosed in the present invention has better flame retardant and fireproof performance, better high temperature resistance and weather resistance, and longer service life through reasonable selection of preparation process parameters. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solution of the present invention, the product of the present invention is further described in detail below in conjunction with embodiments.

[0022] Example 1

[0023] A heat insulation cover material for an automobile exhaust pipe is prepared from the following raw materials in parts by weight: 25 parts of hyperbranched polyborosilazane containing benzene rings, 20 parts of reinforcing materials, 8 parts of ceramic fillers, 3 parts of coupling agents, 20 parts of fluorosilicone-type thermoplastic polyurethane elastomer containing benzene rings, 1 part of 1-isopropenyl-2-benzimidazolone, 1 part of diphenyl (4-vinylphenyl) phosphine oxide, 2 parts of 2,4,6-trivinyl cycloboroxane, 3 parts of 2-acrylamido-2-methylpropane sulfonic acid, 0.8 parts of phosphorus pentoxide, 0.5 parts of polyphosphoric acid and 0.1 parts of a curing agent.

[0024] The benzene ring-containing hyperbranched polyborosilazane is made according to the method in the Chinese invention patent with application announcement number CN117024144A; the reinforcing material is basalt fiber; the average diameter of the reinforcing fiber is 3 μm, and the aspect ratio is 20:1; the ceramic filler is mica powder; the particle size of the ceramic filler is 1000 mesh; the coupling agent is silane coupling agent KH550; the benzene ring-containing fluorosilicone thermoplastic polyurethane elastomer is made according to the method in Example 6 of the authorization announcement number CN111154064B; the curing agent is a mixture of diisopropyl peroxide DCP, dodecyl peroxide LPO, and azobisisoheptonitrile ABVN in a mass ratio of 1:0.8:1.

[0025] A preparation method of the automobile exhaust pipe heat insulation cover material comprises the following steps: after uniformly mixing the raw materials by weight, loading them into a molding mold at 140°C, molding them according to a step-by-step temperature increase molding process system, and obtaining the automobile exhaust pipe heat insulation cover material after pressure relief and demoulding; the step-by-step temperature increase molding process system is: heating to 110°C and keeping the temperature for 0.8 hours, and no axial pressure is applied during the process; then heating to 145°C and keeping the temperature for 1.5 hours, and applying 15MPa axial pressure at the same time, which is the molding pressure; keeping the molding pressure unchanged, heating to 175°C and keeping the temperature for 1 hour, and finally heating to 190°C and keeping the temperature for 0.8 hours.

[0026] Example 2

[0027] A heat insulation cover material for an automobile exhaust pipe is prepared from the following raw materials in parts by weight: 27 parts of hyperbranched polyborosilazane containing benzene rings, 23 parts of reinforcing materials, 9 parts of ceramic fillers, 3.5 parts of coupling agents, 22 parts of fluorosilicone thermoplastic polyurethane elastomer containing benzene rings, 1.5 parts of 1-isopropenyl-2-benzimidazolone, 1.5 parts of diphenyl (4-vinylphenyl) phosphine oxide, 2.5 parts of 2,4,6-trivinyl cycloboroxane, 4 parts of 2-acrylamido-2-methylpropanesulfonic acid, 0.9 parts of phosphorus pentoxide, 0.6 parts of polyphosphoric acid, and 0.15 parts of a curing agent.

[0028] The benzene ring-containing hyperbranched polyborosilazane is made according to the method in the Chinese invention patent with application announcement number CN117024144A; the reinforcing material is carbon fiber; the average diameter of the reinforcing fiber is 5 μm, and the aspect ratio is 23:1; the ceramic filler is talcum powder; the particle size of the ceramic filler is 1200 mesh; the coupling agent is silane coupling agent KH560; the benzene ring-containing fluorosilicone thermoplastic polyurethane elastomer is made according to the method in Example 6 of authorization announcement number CN111154064B; the curing agent is a mixture of diisopropyl peroxide DCP, dodecyl peroxide LPO, and azobisisoheptonitrile ABVN in a mass ratio of 1.5:0.9:1.

[0029] A preparation method of the automobile exhaust pipe heat insulation cover material comprises the following steps: after uniformly mixing the raw materials by weight, loading them into a molding mold at 145°C, molding according to a step-by-step temperature increase molding process system, and obtaining the automobile exhaust pipe heat insulation cover material after pressure relief and demoulding; the step-by-step temperature increase molding process system is: heating to 115°C and keeping warm for 0.9 hours, and no axial pressure is applied during this process; then heating to 148°C and keeping warm for 1.8 hours, while applying an axial pressure of 22MPa, which is the molding pressure; keeping the molding pressure unchanged, heating to 178°C and keeping warm for 1.2 hours, and finally heating to 200°C and keeping warm for 0.9 hours.

[0030] Example 3

[0031] A heat insulation cover material for an automobile exhaust pipe is prepared from the following raw materials in parts by weight: 30 parts of hyperbranched polyborosilazane containing benzene rings, 25 parts of reinforcing materials, 10 parts of ceramic fillers, 4 parts of coupling agents, 25 parts of fluorosilicone-type thermoplastic polyurethane elastomer containing benzene rings, 2 parts of 1-isopropenyl-2-benzimidazolone, 2 parts of diphenyl (4-vinylphenyl) phosphine oxide, 3 parts of 2,4,6-trivinyl cycloboroxane, 4.5 parts of 2-acrylamido-2-methylpropane sulfonic acid, 1.3 parts of phosphorus pentoxide, 0.65 parts of polyphosphoric acid, and 0.2 parts of a curing agent.

[0032] The benzene ring-containing hyperbranched polyborosilazane is made according to the method in the Chinese invention patent with application announcement number CN117024144A; the reinforcing material is boron fiber; the average diameter of the reinforcing fiber is 6 μm, and the aspect ratio is 25:1; the ceramic filler is wollastonite powder; the particle size of the ceramic filler is 1500 mesh; the coupling agent is silane coupling agent KH570; the benzene ring-containing fluorosilicone thermoplastic polyurethane elastomer is made according to the method in Example 6 of the authorization announcement number CN111154064B; the curing agent is a mixture of diisopropyl peroxide DCP, dodecyl peroxide LPO, and azobisisoheptonitrile ABVN in a mass ratio of 2:1:1.

[0033] A preparation method of the automobile exhaust pipe heat insulation cover material comprises the following steps: after mixing the raw materials uniformly by weight, loading them into a molding mold at 150°C, molding them according to a step-by-step temperature increase molding process system, and obtaining the automobile exhaust pipe heat insulation cover material after pressure relief and demoulding; the step-by-step temperature increase molding process system is: heating to 120°C and keeping warm for 1 hour, during which no axial pressure is applied; then heating to 150°C and keeping warm for 2 hours, while applying an axial pressure of 26MPa, which is the molding pressure; keeping the molding pressure unchanged, heating to 180°C and keeping warm for 1.5 hours, and finally heating to 205°C and keeping warm for 1 hour.

[0034] Example 4

[0035] A heat insulation cover material for an automobile exhaust pipe is prepared from the following raw materials in parts by weight: 33 parts of hyperbranched polyborosilazane containing benzene rings, 28 parts of reinforcing materials, 11 parts of ceramic fillers, 4.5 parts of coupling agents, 28 parts of fluorosilicone thermoplastic polyurethane elastomer containing benzene rings, 2.5 parts of 1-isopropenyl-2-benzimidazolone, 2.5 parts of diphenyl (4-vinylphenyl) phosphine oxide, 3.5 parts of 2,4,6-trivinyl cycloboroxane, 5.5 parts of 2-acrylamido-2-methylpropanesulfonic acid, 1.3 parts of phosphorus pentoxide, 0.75 parts of polyphosphoric acid, and 0.25 parts of a curing agent.

[0036] The benzene ring-containing hyperbranched polyborosilazane is made according to the method in the Chinese invention patent with application announcement number CN117024144A; the reinforcing material is basalt fiber; the average diameter of the reinforcing fiber is 8 μm, and the aspect ratio is 28:1; the ceramic filler is a mixture of mica powder, talcum powder, and wollastonite powder in a mass ratio of 1:1:2; the particle size of the ceramic filler is 1800 mesh; the coupling agent is a mixture of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570 in a mass ratio of 1:3:5; the benzene ring-containing fluorosilicone thermoplastic polyurethane elastomer is made according to the method in Example 6 with authorization announcement number CN111154064B; the curing agent is a mixture of diisopropyl peroxide DCP, dodecyl peroxide LPO, and azobisisoheptonitrile ABVN in a mass ratio of 2.5:1.1:1.

[0037] A preparation method of the automobile exhaust pipe heat insulation cover material comprises the following steps: after uniformly mixing the raw materials by weight, loading them into a molding mold at 155° C., molding according to a step-by-step temperature increase molding process system, and obtaining the automobile exhaust pipe heat insulation cover material after pressure relief and demoulding; the step-by-step temperature increase molding process system is: heating to 125° C. and keeping warm for 1.1 hours, during which no axial pressure is applied; then heating to 153° C. and keeping warm for 2.3 hours, while applying an axial pressure of 30 MPa, which is the molding pressure; keeping the molding pressure unchanged, heating to 183° C. and keeping warm for 1.8 hours, and finally heating to 215° C. and keeping warm for 1.1 hours.

[0038] Example 5

[0039] A heat insulation cover material for an automobile exhaust pipe is prepared from the following raw materials in parts by weight: 35 parts of hyperbranched polyborosilazane containing benzene rings, 30 parts of reinforcing materials, 12 parts of ceramic fillers, 5 parts of coupling agents, 30 parts of fluorosilicone-type thermoplastic polyurethane elastomer containing benzene rings, 3 parts of 1-isopropenyl-2-benzimidazolone, 3 parts of diphenyl (4-vinylphenyl) phosphine oxide, 4 parts of 2,4,6-trivinyl cycloboroxane, 6 parts of 2-acrylamido-2-methylpropanesulfonic acid, 1.5 parts of phosphorus pentoxide, 0.8 parts of polyphosphoric acid, and 0.3 parts of a curing agent.

[0040] The benzene ring-containing hyperbranched polyborosilazane is made according to the method in the Chinese invention patent with application announcement number CN117024144A; the reinforcing material is basalt fiber; the average diameter of the reinforcing fiber is 9 μm, and the aspect ratio is 30:1; the ceramic filler is mica powder; the particle size of the ceramic filler is 2000 mesh; the coupling agent is silane coupling agent KH550; the benzene ring-containing fluorosilicone thermoplastic polyurethane elastomer is made according to the method in Example 6 of the authorization announcement number CN111154064B; the curing agent is a mixture of diisopropyl peroxide DCP, dodecyl peroxide LPO, and azobisisoheptonitrile ABVN in a mass ratio of 3:1.2:1.

[0041] A preparation method of the automobile exhaust pipe heat insulation cover material comprises the following steps: after uniformly mixing the raw materials by weight, loading them into a molding mold at 160°C, molding them according to a step-by-step temperature increase molding process system, and obtaining the automobile exhaust pipe heat insulation cover material after pressure relief and demoulding; the step-by-step temperature increase molding process system is: heating to 130°C and keeping the temperature for 1.2 hours, during which no axial pressure is applied; then heating to 155°C and keeping the temperature for 2.5 hours, while applying an axial pressure of 32MPa, which is the molding pressure; keeping the molding pressure unchanged, heating to 185°C and keeping the temperature for 2 hours, and finally heating to 220°C and keeping the temperature for 1.2 hours.

[0042] Comparative Example 1

[0043] A heat insulation cover material for an automobile exhaust pipe is substantially the same as that of Example 1, except that 1-isopropenyl-2-benzimidazolone is not added.

[0044] Comparative Example 2

[0045] A heat insulation cover material for an automobile exhaust pipe is substantially the same as that of Example 1, except that diphenyl (4-vinylphenyl) phosphine oxide is not added.

[0046] In order to further illustrate the unexpected positive technical effects achieved by the products of each embodiment of the present invention, the relevant performance tests were conducted on the automobile exhaust pipe heat insulation cover materials prepared in each example. The test results are shown in Table 1. The test method is as follows:

[0047] (1) Flame retardancy: tested in accordance with UL-94.

[0048] (2) High temperature resistance: Use 1300℃ oxyacetylene flame to burn continuously and record the time it takes for the entire material to be burned through. The gas pressure is about 0.3MPa.

[0049] (3) Weather resistance: Each product was placed in an environment of 85°C × 85% RH for 1000 hours, taken out and cooled to room temperature, and the time it took for the entire material to be burned through was tested according to the test method (2) for high temperature resistance. The retention rate of the time it took for the entire material to be burned through was calculated. The larger the value, the better the weather resistance.

[0050] Table 1

[0051] project Flame retardancy (grade) High temperature resistance (min) Weather resistance (%) Example 1 V-0 >82min 99.69 Example 2 V-0 >86min 99.77 Example 3 V-0 >88min 99.87 Example 4 V-0 >89min 99.92 Example 5 V-0 >94min 99.99 Comparative Example 1 V-1 <71min 98.12 Comparative Example 2 V-1 <74min 98.25

[0052] It can be seen from Table 1 that the automobile exhaust pipe heat insulation cover material disclosed in the embodiment of the present invention has better flame retardancy, high temperature resistance and weather resistance than the comparative example product, and the combined use of diphenyl (4-vinylphenyl) phosphine oxide and 1-isopropenyl-2-benzimidazolone is beneficial to improving the above properties.

[0053] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as described above. However, any technician familiar with the profession can make some changes, modifications and evolutions of the technical content disclosed above without departing from the scope of the technical solution of the present invention, which are all equivalent embodiments of the present invention. At the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A heat insulation cover material for automobile exhaust pipe, characterized in that: The invention is prepared from the following raw materials in parts by weight: 25-35 parts of hyperbranched polyborosilazane containing benzene ring, 20-30 parts of reinforcing material, 8-12 parts of ceramic filler, 3-5 parts of coupling agent, 20-30 parts of fluorosilicone type thermoplastic polyurethane elastomer containing benzene ring, 1-3 parts of 1-isopropenyl-2-benzimidazolone, 1-3 parts of diphenyl (4-vinylphenyl) phosphine oxide, 2-4 parts of 2,4,6-trivinyl cycloboroxane, 3-6 parts of 2-acrylamido-2-methylpropane sulfonic acid, 0.8-1.5 parts of phosphorus pentoxide, 0.5-0.8 parts of polyphosphoric acid and 0.1-0.3 parts of curing agent; the reinforcing material The material is any one of basalt fiber, carbon fiber, and boron fiber; the average diameter of the reinforcing material is 3-9 μm, and the aspect ratio is (20-30):1; the ceramic filler is at least one of mica powder, talcum powder, and wollastonite powder; the particle size of the ceramic filler is 1000-2000 mesh; the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570; the curing agent is a mixture of diisopropyl peroxide DCP, dodecyl peroxide LPO, and azobisisoheptonitrile ABVN in a mass ratio of (1-3):(0.8-1.2):

1.

2. A method for preparing the automobile exhaust pipe heat insulation cover material as claimed in claim 1, characterized in that: The method comprises the following steps: mixing the raw materials uniformly according to weight, loading the raw materials into a molding mold at 140-160 DEG C, molding the materials according to a step-by-step temperature increase molding process, and obtaining the automobile exhaust pipe heat insulation cover material after pressure relief and demolding.

3. The method for preparing the automobile exhaust pipe heat insulation cover material according to claim 2, characterized in that: The step-by-step temperature-increasing molding process is as follows: heating to 110-130° C. and keeping warm for 0.8-1.2 hours, during which no axial pressure is applied; then heating to 145-155° C. and keeping warm for 1.5-2.5 hours, while applying an axial pressure of 15-32 MPa, which is the molding pressure; keeping the molding pressure unchanged, heating to 175-185° C. and keeping warm for 1-2 hours, and finally heating to 190-220° C. and keeping warm for 0.8-1.2 hours.