Composite material repairing slurry and preparation process thereof

Abstract

The invention relates to the technical field of repairing slurry, in particular to composite material repairing slurry and a preparation process thereof. The invention relates to a composite material repairing slurry, which comprises a filler, a thermal expansion agent, a reinforcing fiber, a thermosetting plastic and a solvent according to a mass ratio of (13-15): (4-5): (10-12): (40-45): (40-45), wherein the filler is a carbon nanotube, the thermal expansion agent is selected from one or more of azodiisobutyronitrile, p-toluenesulfonyl hydrazide, N, N '-dinitroso-N, N'-dimethyl terephthalamide and benzenesulfonyl hydrazide, and the reinforcing fiber is selected from one or more of glass fiber, wollastonite fiber, cellulosic fiber and ceramic fiber. The composite material repairing slurry can be heated to expand after being heated at 100 DEG C, cracks are filled, the repairing difficulty of operators is reduced, and the repaired bumper is good in impact resistance.

Description

Technical Field

[0001] This invention relates to the field of repair grout technology, specifically to a composite material repair grout and its preparation process. Background Technology

[0002] Car bumpers are safety devices that absorb and mitigate external impacts, protecting the front and rear of the vehicle. To achieve weight reduction, most car bumpers are made of plastic. However, plastic bumpers have poor impact resistance; even slightly strong impacts can easily damage them, causing cracks or scratches. For bumper damage that doesn't result in serious deformation, the most economical method is to repair it with a repair compound.

[0003] Currently, the automotive repair industry primarily uses epoxy resin adhesive to repair plastic bumpers. Epoxy resin adhesive boasts extremely high bonding strength, can withstand substantial loads, and is resistant to aging, fatigue, and corrosion. Its performance remains stable throughout its expected lifespan, making it suitable for bonding structural components that bear significant forces.

[0004] However, epoxy resin adhesive also has drawbacks as a repair agent for plastic bumpers: while it has high bonding strength, its mechanical properties are insufficient, and it does not help improve the impact resistance of the repaired plastic bumper. In addition, if the crack in the bumper is deep but the surface damage area is small, epoxy resin adhesive is difficult to fully repair the plastic bumper. That is, it is difficult for the epoxy resin adhesive to fully and firmly bond with the contact surface of the repair gap, which may result in the problem of using too much or too little epoxy resin adhesive, requiring multiple rework, increasing labor and time costs. Summary of the Invention

[0005] To address the problem in existing technologies where plastic bumper repair agents often fail to bond firmly to the repair gap, frequently requiring rework, this invention provides a composite material repair slurry and its preparation process. By adding a thermal expansion agent to the composite material repair slurry, the slurry expands upon heating after filling the bumper crack. Bumpers repaired using the composite material repair slurry provided by this invention exhibit strong impact resistance.

[0006] In a first aspect, the present invention provides a composite material repair slurry, comprising a filler, a thermal expansion agent, reinforcing fibers, a thermosetting plastic, and a solvent, wherein the mass ratio of the filler, thermal expansion agent, reinforcing fibers, thermosetting plastic, and solvent is 13-15:4-5:10-12:40-45:40-45; wherein the filler is carbon nanotubes, the thermal expansion agent is selected from one or more of azobisisobutyronitrile, p-toluenesulfonyl hydrazine, N,N'-dinitroso-N,N'-dimethylterephthalamide, and benzenesulfonyl hydrazine, and the reinforcing fibers are selected from one or more of glass fibers, wollastonite fibers, cellulose fibers, and ceramic fibers.

[0007] The thermal expansion temperature of azobisisobutyronitrile is 98℃-102℃, that of p-toluenesulfonyl hydrazine is 103℃-111℃, that of N,N'-dinitroso-N,N'-dimethylterephthalamide is 90℃-105℃, and that of benzenesulfonyl hydrazine is 95℃-100℃. To avoid the above-mentioned composite repair slurry from being activated and expanded by heat before use, the temperature is artificially controlled not to exceed 80℃ during its transportation and storage.

[0008] Furthermore, the carbon nanotubes are either multi-walled carbon nanotubes or single-walled carbon nanotubes.

[0009] Furthermore, the thermal expansion agent is p-toluenesulfonyl hydrazine or benzenesulfonyl hydrazine.

[0010] Furthermore, the reinforcing fibers are ceramic fibers or glass fibers.

[0011] Furthermore, the thermosetting plastic is selected from one or more of thermosetting flame-retardant epoxy resins, phenolic resins, and melamine-formaldehyde resins.

[0012] The curing temperature of thermosetting epoxy resin is 130℃-150℃, the curing temperature of phenolic resin is 120℃-150℃, and the curing temperature of melamine-formaldehyde resin is 120℃-180℃.

[0013] Furthermore, thermosetting plastics are thermosetting flame-retardant epoxy resins or phenolic resins.

[0014] Furthermore, the solvent is N-methylpyrrolidone or anhydrous ethanol.

[0015] Furthermore, the mass ratio of filler, thermal expansion agent, reinforcing fiber, thermosetting plastic and solvent is 15:4:10:40:40.

[0016] Secondly, the present invention provides a preparation process for the above-mentioned composite material repair slurry, wherein the solvent and filler are homogenized and mixed in a high-pressure homogenizer, and after being taken out, a thermal expansion agent, reinforcing fiber and thermosetting plastic are added, and then the composite material repair slurry is dispersed in an IMS online dispersion device.

[0017] Furthermore, the high-pressure homogenizer has a homogenization frequency of 30-35 Hz, a homogenization pressure of 1200-2000 MPa, and a cycle count of 3-6 times; the IMS online dispersion equipment has a rotation speed of 800-1200 rpm, a discharge temperature of ≤40℃, and a viscosity controlled at 7000-7500 cps.

[0018] The beneficial effects of this invention are as follows: This invention provides a composite material repair slurry. By adding a thermal expansion agent, the slurry fills the bumper cracks and expands upon heating, resulting in a stronger bond between the slurry and the bumper. The addition of a certain proportion of reinforcing fibers, fillers, and thermal expansion agents further enhances the mechanical properties of the repaired bumper, particularly its impact resistance. Multiple high-pressure homogenization processes open up the carbon nanotube aggregates, allowing them to disperse fully in the solvent. The remaining components are then added and dispersed in an IMS online dispersion device, controlling the slurry viscosity. This ensures that the composite material repair slurry, when applied to the bumper cracks, penetrates the cracks more easily and does not easily flow out. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0020] Example 1 The composite material repair slurry comprises 15 parts by weight of multi-walled carbon nanotubes, 4 parts by weight of p-toluenesulfonyl hydrazine, 10 parts by weight of ceramic fiber, 40 parts by weight of thermosetting flame-retardant epoxy resin, and 40 parts by weight of anhydrous ethanol.

[0021] Preparation process of composite material repair slurry: Anhydrous ethanol and multi-walled carbon nanotubes are homogenized in a high-pressure homogenizer. The homogenization frequency of the high-pressure homogenizer is 30 Hz, the homogenization pressure is 1200 MPa, and the number of cycles is 3. After removal, p-toluenesulfonyl hydrazine, ceramic fiber and thermosetting flame-retardant epoxy resin are added. Then, the mixture is dispersed in an IMS online dispersion device to obtain the composite material repair slurry. The rotation speed of the IMS online dispersion device is 800 rpm, the discharge temperature is ≤40℃, and the viscosity is controlled within the range of 7000-7500 cps.

[0022] Example 2 The composite material repair slurry comprises 13 parts by weight of multi-walled carbon nanotubes, 5 parts by weight of p-toluenesulfonyl hydrazine, 12 parts by weight of ceramic fiber, 45 parts by weight of thermosetting flame-retardant epoxy resin, and 45 parts by weight of anhydrous ethanol.

[0023] The preparation process is the same as in Example 1.

[0024] Example 3 The composite repair slurry comprises 15 parts by weight of single-walled carbon nanotubes, 4 parts by weight of benzenesulfonyl hydrazine, 10 parts by weight of glass fiber, 40 parts by weight of phenolic resin, and 40 parts by weight of N-methylpyrrolidone.

[0025] Preparation process of composite material repair slurry: N-methylpyrrolidone and single-walled carbon nanotubes are homogenized in a high-pressure homogenizer. The homogenization frequency of the high-pressure homogenizer is 35 Hz, the homogenization pressure is 2000 MPa, and the number of cycles is 6. After removal, benzenesulfonyl hydrazine, glass fiber and phenolic resin are added, and then dispersed in an IMS online dispersion device to obtain the composite material repair slurry. The rotation speed of the IMS online dispersion device is 1200 rpm, the discharge temperature is ≤40℃, and the viscosity is controlled within the range of 7000-7500 cps.

[0026] Comparative Example 1 The composite material repair slurry comprises 15 parts by weight of multi-walled carbon nanotubes, 10 parts by weight of ceramic fibers, 40 parts by weight of thermosetting flame-retardant epoxy resin, and 40 parts by weight of anhydrous ethanol.

[0027] Preparation process of composite material repair slurry: Anhydrous ethanol and multi-walled carbon nanotubes are homogenized in a high-pressure homogenizer. The homogenization frequency of the high-pressure homogenizer is 30 Hz, the homogenization pressure is 1200 MPa, and the number of cycles is 3. After removal, ceramic fibers and thermosetting flame-retardant epoxy resin are added, and then dispersed in an IMS online dispersion device to obtain the composite material repair slurry. The rotation speed of the IMS online dispersion device is 800 rpm, the discharge temperature is ≤40℃, and the viscosity is controlled within the range of 7000-7500 cps.

[0028] Comparative Example 2 The composite material repair slurry comprises 4 parts by weight of p-toluenesulfonyl hydrazine, 25 parts by weight of ceramic fiber, 40 parts by weight of thermosetting flame-retardant epoxy resin, and 40 parts by weight of anhydrous ethanol.

[0029] Preparation process of composite material repair slurry: p-toluenesulfonyl hydrazine, ceramic fiber and thermosetting flame retardant epoxy resin are added to anhydrous ethanol and dispersed in an IMS online dispersion device to obtain composite material repair slurry. The rotation speed of the IMS online dispersion device is 800 rpm, the discharge temperature is ≤40℃, and the viscosity is controlled within the range of 7000-7500 cps.

[0030] Comparative Example 3 The composite material repair slurry comprises 25 parts by weight of multi-walled carbon nanotubes, 4 parts by weight of p-toluenesulfonyl hydrazine, 40 parts by weight of thermosetting flame-retardant epoxy resin, and 40 parts by weight of anhydrous ethanol.

[0031] Preparation process of composite material repair slurry: Anhydrous ethanol and multi-walled carbon nanotubes are homogenized in a high-pressure homogenizer. The homogenization frequency of the high-pressure homogenizer is 30 Hz, the homogenization pressure is 1200 MPa, and the number of cycles is 3. After removal, p-toluenesulfonyl hydrazine and thermosetting flame-retardant epoxy resin are added, and then dispersed in an IMS online dispersion device to obtain the composite material repair slurry. The rotation speed of the IMS online dispersion device is 800 rpm, the discharge temperature is ≤40℃, and the viscosity is controlled within the range of 7000-7500 cps.

[0032] Comparative Example 4 The composite material repair slurry comprises 15 parts by weight of multi-walled carbon nanotubes, 2 parts by weight of p-toluenesulfonyl hydrazine, 10 parts by weight of ceramic fiber, 40 parts by weight of thermosetting flame-retardant epoxy resin, and 40 parts by weight of anhydrous ethanol.

[0033] The preparation process of the composite material repair grout is the same as in Example 1.

[0034] Comparative Example 5 The composite material repair slurry comprises 5 parts by weight of multi-walled carbon nanotubes, 4 parts by weight of p-toluenesulfonyl hydrazine, 5 parts by weight of ceramic fiber, 40 parts by weight of thermosetting flame-retardant epoxy resin, and 40 parts by weight of anhydrous ethanol.

[0035] The preparation process of the composite material repair grout is the same as in Example 1.

[0036] Experiment Example 1 Performance Testing Twelve plastic bumpers of the same manufacturer and model were obtained from an auto repair shop and cut into 96 identical sample pieces. These samples underwent the same crack treatment and were randomly divided into eight groups (Examples 1-3 and Comparative Examples 1-5), with 12 pieces in each group. The damaged areas of the plastic bumper sample pieces were cleaned of dust and dirt. The corresponding composite material repair slurry was applied to the damaged cracks, and the samples were heated at 100°C for 10 minutes to allow the slurry to expand and fully fill the cracks. They were then heated at 130°C for 10 minutes to cure the slurry. After removal, the surface was sanded. Three pieces from each group were randomly selected for the following tests: Gasoline resistance test: Refer to Method A of GB / T 9274 Determination of resistance to liquid media for paints and varnishes. Soak in 92# gasoline for 24 hours, remove and rinse to remove residual liquid, and observe the repair condition of composite material repair slurry. Alkali resistance test: Refer to Method A of GB / T 9274 Determination of resistance to liquid media for paints and varnishes. Immerse in 0.1 mol / L sodium hydroxide for 24 hours, remove and rinse to remove residual liquid, and observe the repair condition of the composite material repair slurry. Acid resistance test: Refer to Method A of GB / T 9274 Determination of resistance to liquid media for paints and varnishes. Immerse in 0.05 mol / L sulfuric acid for 24 hours. After rinsing to remove residual liquid, observe the repair condition of the composite material repair slurry. Impact performance test: The impact strength of the unnotched cantilever beam specimen was tested in accordance with GB / T 1483-1996 Plastic Cantilever Beam Impact Test Method.

[0037] The specific results are shown in Table 1.

[0038] Table 1. Multiple performance tests of composite repair grout

[0039] As shown in Table 1, in the tests of gasoline resistance, acid resistance, and alkali resistance, all plastic bumper samples from Examples 1-3 and Comparative Examples 2-3 passed the tests. There were no visible cracks at the repair sites, and the composite material repair slurry did not peel off. In the impact performance test, the impact resistance of the plastic bumper samples from Examples 1-3 was significantly better than that of Comparative Examples 2-3, indicating that the composite material repair slurry provided by the present invention has good adhesion to the bumper, and the repaired bumper has strong impact resistance.

[0040] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A composite material repair grout, characterized in that, The product comprises fillers, thermal expansion agents, reinforcing fibers, thermosetting plastics, and solvents, with a mass ratio of 13-15:4-5:10-12:40-45:40-45. The filler is carbon nanotubes, the thermal expansion agent is selected from one or more of azobisisobutyronitrile, p-toluenesulfonyl hydrazine, N,N'-dinitroso-N,N'-dimethylterephthalamide, and benzenesulfonyl hydrazine, and the reinforcing fibers are selected from one or more of glass fibers, wollastonite fibers, cellulose fibers, and ceramic fibers.

2. The composite material repair grout as described in claim 1, characterized in that, Carbon nanotubes can be multi-walled or single-walled.

3. The composite material repair grout as described in claim 1, characterized in that, The thermal expansion agent is p-toluenesulfonyl hydrazine or benzenesulfonyl hydrazine.

4. The composite material repair grout as described in claim 1, characterized in that, The reinforcing fibers are ceramic fibers or glass fibers.

5. The composite material repair grout as described in claim 1, characterized in that, Thermosetting plastics are selected from one or more of thermosetting flame-retardant epoxy resins, phenolic resins, and melamine-formaldehyde resins.

6. The composite material repair grout as described in claim 1, characterized in that, Thermosetting plastics are thermosetting flame-retardant epoxy resins or phenolic resins.

7. The composite material repair grout as described in claim 1, characterized in that, The solvent is N-methylpyrrolidone or anhydrous ethanol.

8. The composite material repair grout as described in claim 1, characterized in that, The mass ratio of filler, thermal expansion agent, reinforcing fiber, thermosetting plastic and solvent is 15:4:10:40:

40.

9. A preparation process for the composite material repair slurry as described in claim 1, characterized in that, Solvents and fillers are homogenized in a high-pressure homogenizer, and after being removed, thermal expansion agents, reinforcing fibers and thermosetting plastics are added. Then, the mixture is dispersed in an IMS online dispersion device to obtain a composite material repair slurry.

10. The preparation process of the composite material repair slurry as described in claim 9, characterized in that, The high-pressure homogenizer has a homogenization frequency of 30-35 Hz, a homogenization pressure of 1200-2000 MPa, and a cycle count of 3-6 times; the IMS online dispersion equipment has a rotation speed of 800-1200 rpm, a discharge temperature of ≤40℃, and a controlled viscosity of 7000-7500 cps.

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