A polymer powder material, a cold-sprayed product, and a method for preparing the cold-sprayed product.

Abstract

The present invention provides a polymer powder material, a cold spray product and a method for preparing the cold spray product. The polymer powder material includes a plurality of thermosetting materials with different activation temperatures, wherein the activation temperature of the thermosetting material with a low activation temperature is lower than the softening point of all the thermosetting materials with a high activation temperature; in the process of sequentially curing all the thermosetting materials, the curing degree of the first cured thermosetting material reaches 80% before the next thermosetting material is cured; the curing temperature of each thermosetting material is between the activation temperature of the thermosetting material and the softening point of the next cured thermosetting material. The present invention controls the curing order and degree of thermosetting materials with different activation temperatures through a segmented curing process, ensuring that each layer of material is cured within its optimal performance range, thereby avoiding the softening and deformation problems of the polymer powder material at high temperatures.

Description

Technical Field

[0001] The invention relates to the technical field of cold spraying technology, in particular to a polymer powder material, a cold spraying product and a preparation method of the cold spraying product. Background Art

[0002] Cold spraying has become a key technology in the manufacturing industry due to its unique low-temperature operating environment and wide material applicability. This technology achieves rapid deposition and bonding of materials by spraying powder materials onto the surface of the workpiece under low-temperature conditions, thereby improving the surface performance of the workpiece without damaging the original performance of the workpiece. In the automotive manufacturing industry, the application of cold spraying technology has greatly improved the durability and quality of the car's appearance. By applying a uniform coating on the surface of the car, it not only enhances the corrosion resistance and wear resistance of the car, but also improves its overall aesthetics. In addition, in the field of aerospace, cold spraying technology also plays an important role. By repairing and protecting key components of aircraft engines, this technology effectively extends the service life of components and reduces maintenance costs. In the field of medical device manufacturing and electronic equipment production, the application of cold spraying technology should not be underestimated. By applying a wear-resistant and corrosion-resistant coating on the surface of the product, it not only improves the service life of the product, but also ensures its stable performance in complex environments.

[0003] At present, the main powder materials used in cold spraying process include metal materials, ceramic materials and polymer materials. In non-shape-maintaining application scenarios, the main function of powder materials is to evenly cover the surface of parts and provide necessary surface functions. In shape-maintaining applications, metal and ceramic materials have higher melting points and can avoid softening and deformation during the cold spraying process and use, meeting the requirements of shape-maintaining applications.

[0004] However, polymer materials still face challenges in cold spray products that need to maintain their shape. Due to the low melting point of polymer materials, they are prone to deformation in high temperature environments, which limits their use in shape-maintaining applications. Curable polymer materials can extend their use temperature range after high-temperature curing treatment. However, the material takes a certain amount of time to cure, so in an incompletely cured state, polymer materials are prone to softening and deformation during heating, which may cause deformation of the coating surface features or a decrease in part accuracy, thereby affecting the normal use and performance of the product.

[0005] Therefore, in order to further promote the application and development of cold spray technology in the field of polymer materials, it is urgent to develop an effective method to solve the softening and deformation problem of polymer materials manufactured by cold spraying during heating and curing. By optimizing the curing process and improving the properties of powder materials, it is expected to achieve efficient application of polymer materials in cold spray products, thereby providing more reliable and high-performance cold spray product solutions for various industries. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a method for manufacturing a polymer powder material and a cold sprayed product thereof, which solves the problems raised in the above-mentioned background technology.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] According to a first aspect of the present invention, there is provided a polymer powder material for use in a cold spray process, comprising a plurality of thermosetting materials having different activation temperatures, wherein the activation temperature of the thermosetting material having a low activation temperature is lower than the softening point of all the thermosetting materials having a high activation temperature;

[0009] In the process of sequentially curing all the heat-curing materials, the curing degree of the first heat-curing material reaches 80% before the curing of the next heat-curing material;

[0010] The curing temperature of each heat-curing material is between the activation temperature of the heat-curing material and the softening point of the next cured heat-curing material.

[0011] Since the softening point affects the deformation of the material and the activation temperature affects the cross-linking reaction of the material, by limiting the curing temperature of each material, when the first-cured thermosetting material is cured, the later-cured thermosetting material plays a role in maintaining the shape, and when the later-cured thermosetting material is cured, the already cured thermosetting material plays a role in maintaining the shape. Furthermore, the softening and deformation problem of the cold-sprayed product during the post-heating curing process is solved, and the polymer material maintains the desired shape during the post-heating curing process.

[0012] Preferably, the activation temperature of the low activation temperature heat-curing material differs from the softening point of all high activation temperature heat-curing materials by at least 5°C.

[0013] Preferably, the polymer powder material further comprises a first filling material, which is a non-thermosetting material, and the softening point or melting point of the non-thermosetting material is greater than the curing reaction activation temperature of the last cured thermosetting material.

[0014] Preferably, the non-thermosetting material includes at least one of metal, metal oxide or polymer.

[0015] Preferably, the sum of the volumes of the plurality of thermosetting materials accounts for no less than 20% of the volume of the polymer material powder.

[0016] Preferably, the thermosetting material comprises a resin and a curing agent, and the resin is selected from at least one of polyester resin, polyimide resin, epoxy resin, phenolic resin, urea-formaldehyde resin, acrylic resin, fluorocarbon resin, melamine formaldehyde resin, furan resin, rosin resin, and fluoroolefin vinyl ether copolymer.

[0017] Preferably, the polymer powder material further includes a second filling material, and the second filling material is selected from at least one of a pigment, a dye, a leveling agent or a surfactant.

[0018] Preferably, the polymer powder material has a shape selected from at least one of powder, granule or line.

[0019] According to a second aspect of the present invention, there is provided a use of a polymer powder material in a cold sprayed product.

[0020] According to a third aspect of the present invention, there is provided a method for preparing a cold sprayed product, wherein a polymer powder material is cold sprayed to produce a product having a predetermined shape;

[0021] The sample is cured by a sequential curing method so that the sample is completely cured;

[0022] The curing temperature of each material is between the activation temperature of the material and the softening point of the next cured material.

[0023] The present invention provides a polymer powder material, a cold sprayed product and a method for preparing the cold sprayed product. The invention has the following beneficial effects:

[0024] The present invention provides a polymer powder material which controls the curing sequence and degree of thermosetting materials with different activation temperatures through a segmented curing process, thereby ensuring that each thermosetting material is cured within a temperature range that does not affect other thermosetting materials, thereby avoiding the softening and deformation problems of the entire material under high-temperature curing. In addition, the mechanical properties, temperature resistance and chemical resistance of the material are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Graph showing the softening range test results of polymer powder C, polymer powder P1, and polymer powder P2 of Example 1 of the present invention;

[0026] Figure 2The morphology of the product of the polymer powder of Example 1 of the present invention, wherein (a) is the morphology of the product of the polymer powder C, (b) is the morphology of the product of the polymer powder P1; (c) is the morphology of the product of the polymer powder P2;

[0027] Figure 3 The morphology of the polymer powder product of Example 1 of the present invention after post-heating and curing, wherein (a) shows the morphology of polymer powder C after heating and curing, (b) shows the morphology of polymer powder P1 after heating and curing, and (c) shows the morphology of polymer powder P2 after heating and curing;

[0028] Figure 4 1 and 2 are differential scanning calorimetry (DSC) curves of polymer powder P1 and polymer powder P2 according to Example 1 of the present invention. DETAILED DESCRIPTION

[0029] In order to better illustrate the content of the present invention, a detailed description is given below in conjunction with specific embodiments.

[0030] According to an exemplary embodiment of the present invention, the present invention provides a polymer powder material for use in a cold spray process, comprising a plurality of thermosetting materials having different activation temperatures, wherein the activation temperature of the thermosetting material having a low activation temperature is lower than the softening point of all the thermosetting materials having a high activation temperature;

[0031] In the process of sequentially curing all the heat-curing materials, the curing degree of the first heat-curing material reaches 80% before the curing of the next heat-curing material;

[0032] The curing temperature of each heat-curing material is between the activation temperature of the heat-curing material and the softening point of the next cured heat-curing material.

[0033] It should be noted that the polymer powder material provided by the present invention contains at least two thermosetting materials with different activation temperatures, each thermosetting material is composed of a curing agent and a resin, and the curing agent is used to adjust the resin to undergo a curing reaction, so that the thermosetting materials have different activation temperatures and softening points, thereby making different thermosetting materials have different activation temperatures and softening points. The present invention limits the curing temperature of each thermosetting material so that the curing temperature is between the activation temperature of the curing material and the softening point of the next cured thermosetting material, and further limits the curing degree of different thermosetting materials, thereby ensuring that each thermosetting material is cured within a temperature range that does not affect other thermosetting materials, thereby avoiding the softening and deformation problems of the entire material under high-temperature curing.

[0034] In a specific embodiment, the activation temperature of the low activation temperature heat-curing material differs from the softening point of all high activation temperature heat-curing materials by at least 5°C.

[0035] In a specific embodiment, the polymer powder material further includes a first filling material, which is a non-thermosetting material, and the softening point or melting point of the non-thermosetting material is greater than the curing reaction activation temperature of the last cured thermosetting material. Specifically, the non-thermosetting material includes at least one of a metal, a metal oxide or a polymer. The selected non-thermosetting material is a hard particle, and filling it into the polymer material can not only further avoid softening and deformation of the polymer material during the post-heating curing process, but also improve the mechanical properties of the polymer material.

[0036] In a specific embodiment, the sum of the volumes of the multiple thermosetting materials accounts for no less than 20% of the volume of the polymer material powder. By limiting the sum of the volumes of the thermosetting materials, the softening and deformation of the sample made of the polymer material during the post-heating and curing process can be further reduced.

[0037] In a specific embodiment, the thermosetting material includes a resin and a curing agent, and the resin is selected from at least one of polyester resin, polyimide resin, epoxy resin, phenolic resin, urea-formaldehyde resin, acrylic resin, fluorocarbon resin, melamine formaldehyde resin, furan resin, rosin resin, and fluoroolefin vinyl ether copolymer.

[0038] In a specific embodiment, the polymer powder material further includes a second filling material, and the second filling material is selected from at least one of a pigment, a dye, a leveling agent or a surfactant.

[0039] In a specific embodiment, the polymer powder material has a shape selected from at least one of powder, granule or line.

[0040] According to an exemplary embodiment of the present invention, a method for preparing a cold sprayed product using a polymer powder material, wherein the polymer powder material is manufactured into a product having a predetermined shape by a cold spraying process, at a first heating temperature, the first cured thermosetting material undergoes a curing reaction first, while the later cured thermosetting material does not undergo a curing reaction, and the later cured thermosetting material plays a supporting role, and the first heating temperature is between the activation temperature of the first cured thermosetting material and the softening point of the later cured thermosetting material; the temperature is raised from the first heating temperature to a second heating temperature, at the second heating temperature, the later cured thermosetting material undergoes curing, and the cured thermosetting material plays a supporting role, and the second heating temperature is greater than the curing reaction activation temperature of the later cured thermosetting material.

[0041] The polymer powder material of the present invention is further described below in conjunction with specific embodiments.

[0042] A polymer powder material includes two thermosetting materials. The powder is made into a cylindrical sample by using a cold spraying technology, and the sample is then gradually heated and cured to form a completely cured sample.

[0043] Thermosetting materials use commercially available bisphenol A epoxy resin powders (E50 and E57, respectively) and two curing agents (A80 and A95, respectively) to prepare solid thermosetting powders. The epoxy value of E50 is between 0.09mol / 100g and 0.14mol / 100g, and the epoxy value of E57 is between 0.05mol / 100g and 0.06mol / 100g. A80 and A95 are imidazole curing agents with activation temperatures of 80°C and 105°C, respectively. The average diameters of E50 and E57, A80 and A95 are 3μm~5μm, and their powder particles have irregular shapes at the microscopic level.

[0044] The production process of polymer powder is divided into two stages. In the first stage, a single thermosetting powder is produced. First, E50 and A80 are mixed in a mass ratio of 4:1, and a hydraulic press is used to press them into tablets at room temperature, and then the tablets are crushed into powder to obtain thermosetting powder P1. E57 and A95 are used in a mass ratio of 4:1 to prepare thermosetting powder P2 in the same process. The second stage is to make a composite thermosetting powder. P1 and P2 are mixed in a mass ratio of 1:1, and a hydraulic press is used to press them into tablets at room temperature, and then the tablets are crushed into powder to obtain thermosetting powder C. The average diameter of thermosetting powder C is 50μm, of which the average diameter of thermosetting powder P1 and thermosetting powder P2 used to make thermosetting powder C is 20μm. It should be noted that in order to compare the curing effect, the average diameter of thermosetting powder P1 and thermosetting powder P2 as a comparative example is 50μm.

[0045] In order to determine the curing temperature for subsequent heating, the softening points of powders P1, P2 and C were tested: the powders of P1, P2 and C were pressed into discs with a thickness of 1 mm, placed on a programmable heating table, and then a steel ball with a diameter of 5 mm and a mass of 20 g was placed on the pressed disc. The heating table was increased from 30°C to 120°C at a rate of 10°C / min, and the distance the steel ball descended was measured in real time with a micrometer, and the percentage value of the steel ball indentation depth to the disc thickness was calculated, as shown in Fig. Figure 1 It can be seen that the discs of powder P1 and powder P2 soften sharply after 68°C and 103°C respectively, while the indentation curve of the disc of powder C is between the two and begins to soften significantly after 85°C. The composition and characteristics of powder C are shown in Table 1.

[0046] Table 1

[0047] Thermosetting powder C with an average diameter of 50μm, thermosetting powder P1 with an average diameter of 50μm, and thermosetting powder P2 with an average diameter of 50μm were sprayed on a low-pressure cold spray system to produce cylindrical samples. The nozzle of the system is a Laval nozzle with an outlet diameter of 5mm. The substrate for powder deposition is nylon-66. The nozzle is perpendicular to the substrate, and 0.8MPa compressed air is used for spraying. During the 3D printing process, the nozzle is always aimed at a fixed point on the substrate for spraying, and the powder accumulates layer by layer to form a cylindrical shape. As the height of the cylinder increases, the nozzle moves in the vertical direction, always maintaining a distance of 10mm from the upper surface of the printed sample. Finally, cylindrical samples of thermosetting powder C, thermosetting powder P1 and thermosetting powder P2 were obtained, as shown in the figure. Figure 2 As shown in Figures (a) to (c).

[0048] In order to keep the original shape of the powder C sample during the curing process, the sample was heated in steps. In the first heating, the sample was heated at a constant temperature of 85°C for 1 hour. At this time, the P1 component softened and cured, and the P2 component was in a slightly expanded and unsoftened state. The P2 component provided support for the entire C. The second heating was heated at 150°C for half an hour. At this time, the P1 component was completely cured, and the P2 component softened and cured. The P1 component provided support for the entire C.

[0049] Figure 3 (a) to (c) are the morphologies of the samples of the thermosetting powder C, thermosetting powder P1, and thermosetting powder P2 according to Example 1 of the present invention after post-heating and curing. The sample of the thermosetting powder P1 deformed during the first constant temperature heating, and the sample of the thermosetting powder P2 deformed during the second constant temperature heating, while the sample of the thermosetting powder C basically maintained its original shape during the heating process, greatly reducing deformation.

[0050] In order to determine the curing reaction during the heating process, differential scanning calorimetry (DSC) was performed on the heat-curing powder P1 and the heat-curing powder P2. Figure 4 1 and 2 are differential scanning calorimetry (DSC) curves of the thermosetting powder P1 and the thermosetting powder P2 according to Example 1 of the present invention.

[0051] according to Figure 4As shown in the figure, after the first constant temperature heating, the exothermic peak of the DSC curve of the thermosetting powder P1 has been greatly reduced, indicating that P1 has undergone an obvious curing reaction during the first constant temperature heating; while the exothermic peak of P2 has not changed significantly, indicating that P2 has not undergone a curing reaction. After the second constant temperature heating, the exothermic peak of the DSC curve of the thermosetting powder P2 disappeared, indicating that P2 has undergone a curing reaction during the second constant temperature heating. It can be confirmed that during the first constant temperature heating of the thermosetting powder C sample, although component P1 softened, the unsoftened component P2 supported the entire sample; and during the second constant temperature heating, although component P2 softened, the cured component P1 supported the entire sample. Therefore, only about 50% of the material of the thermosetting powder C sample softened during the entire heating process, and basically maintained its original shape.

[0052] It can be seen that the solution proposed by the present invention can greatly reduce deformation and keep the cold sprayed product in its original shape.

[0053] This embodiment prepares a polymer composite powder, which is composed of three thermosetting materials. First, three commercially available bisphenol A epoxy resin powders and three curing agents are used to prepare three thermosetting materials P1, P2 and P3 according to different ratios. Table 2 shows the component ratios and properties of P1, P2 and P3. Among them, P1 and P2 have the same components as those in Example 1, and the epoxy value of E669 of P3 is between 2000 and 3500 g / eq.

[0054] Table 2

[0055] P1, P2 and P3 were accurately weighed and fully mixed in a mass ratio of 1:1:1 to obtain a thermosetting composite powder C. The powder C was then formed into a cylindrical sample using a cold spraying technique.

[0056] To achieve complete curing of the sample, the printed sample was gradually heated and cured. The curing process was carried out in three steps, curing the three thermal curing materials P1, P2 and P3 in sequence.

[0057] In the first step, P1 was cured by heating at 85°C. At this temperature, P1 softened and cross-linked to form a solid body, while P2 and P3 did not soften. At this time, about 1 / 3 of the volume of the sample was softened.

[0058] After P1 is completely cured, the second step of heating is performed at 110°C to cure P2. P2 softens and cures, the cured P1 no longer softens, and P3 remains unsoftened. At this point, the softened volume is about 1 / 3, and the cured P1 and unsoftened P3 together provide support for the sample.

[0059] After P2 is cured, the third step of heating is performed at 180°C to cure P3. At this time, the cured P1 and P2 provide support for the sample, and the softened volume is about 1 / 3.

[0060] Through the above three steps of curing, a completely cured sample was finally obtained. During the entire curing process, the volume of the softened material was always controlled at about 1 / 3, which was significantly lower than the 50% softening ratio of Example 1.

[0061] This method uses the difference in softening temperature of multiple thermosetting materials to control the proportion of softened volume during the curing process, thereby providing the sample with better shape retention. It can be expected that with the increase in the number of thermosetting materials and the balance of the proportion of various materials, the softened volume proportion will be further reduced, which is conducive to the manufacture of complex shaped parts with higher strength requirements.

[0062] The difference between this comparative example and Example 1 is that the resin of P2 is changed to E50, and the powder and properties of C powder are shown in Table 3.

[0063] Table 3

[0064] Since resin is the main component in the thermosetting material, and the resin of P1 and P2 is the same, the softening points of P2 and P1 are approximately equal. Since the activation temperature of the thermosetting material depends on the activation temperature of the curing agent, the curing agents of P1 and P2 are different, so at this time, the activation temperatures of P1 and P2 are different. However, the sample made of such a composition cannot maintain its shape during the heating process, because no matter what curing temperature is selected, as long as P1 softens, P2 will soften. The softening ratio of the entire material far exceeds 50% of Example 1. Therefore, only requiring a difference between the activation temperatures of the materials cannot guarantee that the materials will not soften and deform during the curing process.

[0065] The difference between this comparative example and Example 1 is that the resin of P2 is changed to E55. The powder and properties of C powder are shown in Table 4.

[0066] Table 4

[0067] The softening point of E55 is 78°C. At this time, the softening point of the material that meets the low activation temperature is lower than the softening point of all the materials with high activation temperatures, but the sample made of such a composition cannot maintain its shape during the heating process. Because when curing P1, the curing temperature must be greater than its activation temperature of 80°C, that is, it is also greater than the softening point of P2, so P2 will soften. The overall softening ratio of the material far exceeds 50% of Example 1. Furthermore, the softening point of the material with a low activation temperature is lower than the softening point of all the materials with high activation temperatures, which cannot guarantee that the material will not soften and deform during the curing process.

[0068] The difference between this comparative example and Example 1 is that the temperature of the first heating curing is between 103°C and 105°C. Although P2 curing is not triggered, P2 softens, causing the overall softening ratio of the material to far exceed 50% of Example 1. Therefore, if the curing temperature is not between the activation temperature of the material and the softening point of the next curing material, the material will deform.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polymer powder material for cold spraying process, characterized in that: The invention comprises a plurality of heat-curing materials having different activation temperatures, wherein the activation temperature of the heat-curing materials with low activation temperatures is lower than the softening point of all the heat-curing materials with high activation temperatures; In the process of sequentially curing all the heat-curing materials, the curing degree of the first heat-curing material reaches 80% before the curing of the next heat-curing material; The curing temperature of each heat-curable material is between the activation temperature of the heat-curable material and the softening point of the next cured heat-curable material; The activation temperature of the low activation temperature heat-curable material differs by at least 5° C. from the softening point of all high activation temperature heat-curable materials.

2. A polymer powder material according to claim 1, characterized in that: The first filling material is a non-thermosetting material, and the softening point or melting point of the non-thermosetting material is greater than the curing reaction activation temperature of the last cured thermosetting material.

3. A polymer powder material according to claim 2, characterized in that: The non-thermosetting material includes at least one of a metal, a metal oxide or a polymer.

4. A polymer powder material according to claim 1, characterized in that: The sum of the volumes of the multiple thermosetting materials accounts for no less than 20% of the volume of the polymer powder material.

5. The polymer powder material according to claim 1, characterized in that: The thermosetting material comprises a resin and a curing agent, wherein the resin is selected from at least one of polyester resin, polyimide resin, epoxy resin, phenolic resin, urea-formaldehyde resin, acrylic resin, fluorocarbon resin, melamine formaldehyde resin, furan resin, rosin resin, and fluoroolefin vinyl ether copolymer.

6. The polymer powder material according to claim 1, characterized in that: The invention also includes a second filling material, wherein the second filling material is selected from at least one of a pigment, a dye, a leveling agent or a surfactant.

7. Use of the polymer powder material according to any one of claims 1 to 6 in cold spraying products.

8. A method for preparing a cold sprayed product according to claim 7, characterized in that: Using a cold spray process to produce a product with a predetermined shape using polymer powder materials; The product is cured by a sequential curing method so that the product is completely cured; The curing temperature of each material is between the activation temperature of the material and the softening point of the next cured material.

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