Surface treatment methods for gas springs, gas springs, automotive suspension structure and applications

Abstract

The application relates to an oil-gas spring surface treatment method, which comprises the following steps: pre-treating the surface of the oil-gas spring to remove surface grease and moisture; applying a primer on the surface of the oil-gas spring and performing flash drying treatment; applying a topcoat on the surface of the primer after the flash drying treatment and away from the surface of the oil-gas spring to perform drying treatment, so as to obtain a primer paint layer and a topcoat paint layer arranged on the outer surface of the oil-gas spring in sequence; the primer comprises an epoxy resin, zinc powder, a curing agent and a solvent and the like. The paint layer formed on the surface of the oil-gas spring by the process has good bonding force, is not easy to fall off, has better service effect and can play a better protection role. The application further provides an oil-gas spring, an automobile suspension structure and application. Since the oil-gas spring has a longer service time and a more stable working condition, the operation stability and application of the automobile suspension structure are more favorable to be improved.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology for gas springs, and in particular to surface treatment methods for gas springs, gas springs, automotive suspension structures and applications. Background Technology

[0002] As an elastic element of vehicle suspension, gas springs require surface treatment to improve corrosion resistance. Traditional surface treatment methods are complex, time-consuming, and yield poor results, leading to coating peeling during use and failing to adequately protect the gas springs. Summary of the Invention

[0003] Based on this, the purpose of this application includes providing a surface treatment method for gas springs, which can obtain a paint layer with high adhesion to the gas spring and good oil resistance and aging resistance using a relatively simple method.

[0004] In addition, this application also provides a gas spring, an automotive suspension structure, and its application.

[0005] A first aspect of this application provides a surface treatment method for a gas spring, comprising the following steps:

[0006] The surface of the gas spring is pretreated to remove grease and moisture.

[0007] The primer is applied to the surface of the gas spring and then flash-dried.

[0008] Apply the topcoat to the primer surface that has undergone flash-drying, and then dry it.

[0009] The primer, by weight, comprises: 11 to 13 parts epoxy resin, 5 to 7 parts xylene, 2 to 4 parts n-butanol, 0.1 to 0.2 parts hydrogenated castor oil, 0.2 to 0.4 parts dispersant, 0.1 to 0.3 parts defoamer, 0.4 to 0.6 parts leveling agent, 24 to 26 parts zinc powder, and 11 to 13 parts first curing agent.

[0010] In some embodiments, the surface treatment method for the gas spring satisfies one or more of the following conditions:

[0011] (1) The temperature of the flash drying treatment is 20℃~30℃;

[0012] (2) The flash drying time is 15 min to 25 min.

[0013] In some embodiments, the surface treatment method for the gas spring satisfies one or more of the following conditions:

[0014] (1) The drying temperature is 70℃~90℃;

[0015] (2) The drying time is 15 min to 25 min.

[0016] In some embodiments, the surface treatment method for gas springs satisfies one or more of the following conditions:

[0017] (1) The zinc powder in the primer has a mesh size selected from 300 mesh to 500 mesh;

[0018] (2) The first curing agent in the topcoat is selected from biuret and its derivatives;

[0019] (3) The weight ratio of the first curing agent in the primer to the epoxy resin is (0.8 to 1.2):1.

[0020] In some embodiments, in the surface treatment method for the gas spring, the raw materials of the topcoat, by weight, include: 54 to 56 parts of hydroxyl acrylic resin, 6 to 8 parts of propylene glycol methyl ether acetate, 24 to 26 parts of titanium dioxide, 4 to 6 parts of film-forming aid, 0.4 to 0.6 parts of leveling agent, 0.1 to 0.3 parts of defoamer, and 14 to 16 parts of second curing agent.

[0021] In some embodiments, the surface treatment method for the gas spring satisfies one or more of the following conditions:

[0022] (1) The second curing agent in the topcoat is selected from isocyanates and their derivatives;

[0023] (2) The weight ratio of the second curing agent in the topcoat to the hydroxyl acrylic resin is (14-16):(50-60).

[0024] A second aspect of this application provides a gas spring, comprising a gas spring, wherein a primer layer and a topcoat layer are sequentially disposed on the outer surface of the gas spring.

[0025] The primer layer and the topcoat layer are prepared using the surface treatment method described in the first aspect.

[0026] In some embodiments, the thickness of the primer layer of the gas spring is 15μm to 30μm, and the thickness of the topcoat layer is 10μm to 20μm.

[0027] A third aspect of this application provides an automotive suspension structure, including the gas spring described in the second aspect.

[0028] A fourth aspect of this application provides the application of the gas spring described in the second aspect or the automotive suspension structure described in the third aspect in the manufacture of a shock-absorbing structure for a vehicle. The surface treatment method for the gas spring components provided in this application is simple. It involves flash-drying the primer and drying the topcoat. During surface application, oil seepage from the gas spring can affect the surface treatment effect. Furthermore, the process cost is low, and the resulting coating has good adhesion to the gas spring surface, is not easily peeled off, has good service performance, and provides good protection.

[0029] The component surface of the gas spring provided in this application has a primer layer and a topcoat layer that are tightly bonded to it. The component of the gas spring has good surface oil resistance and aging resistance, and also helps to improve the corrosion resistance of the gas spring, thereby obtaining a longer service life and more stable operating conditions.

[0030] The automotive suspension structure provided in this application includes a gas spring with a longer service life and more stable operating conditions, which is beneficial to improving the operational stability of the automotive suspension structure.

[0031] The vehicle using the gas spring or the vehicle suspension structure provided in this application. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 The image shows a cross-cut test performed on the paint layer formed on the surface of the gas spring using the method in Example 1 after aging under a xenon lamp for 1000 hours.

[0034] Figure 2 The image in the middle shows a cross-cut test conducted on the paint layer formed on the surface of the gas spring using the method of Comparative Example 1 after aging under a xenon lamp for 1000 hours.

[0035] Figure 3 The middle image shows a photograph of the paint layer formed on the surface of the gas spring using the method of Comparative Example 1, after being left to stand for 6 months in an actual working environment. Detailed Implementation

[0036] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0037] The implementation of the present invention will now be described in detail with reference to the accompanying drawings. This embodiment is implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0039] the term

[0040] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0041] In this invention, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0042] In this invention, terms such as "further" and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0043] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0044] In this invention, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the distribution of selectable values ​​within a numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0045] In this invention, the term "room temperature" generally refers to 4℃ to 35℃, and preferably 20℃ ± 5℃. In some embodiments of this invention, room temperature refers to 20℃ to 30℃.

[0046] In this invention, unless otherwise specified, the temperature parameters are allowed to be either constant temperature or vary within a certain temperature range. It should be understood that the constant temperature treatment allows temperature fluctuations within the precision range controlled by the instrument. Fluctuations are permitted within ranges such as ±5℃, ±4℃, ±3℃, ±2℃, and ±1℃.

[0047] In this invention, if the unit of a data range is only followed by the right endpoint, it indicates that the units of the left and right endpoints are the same. For example, 2-5h means that the units of the left endpoint "2" and the right endpoint "5" are both h (hours).

[0048] A hydropneumatic spring is generally a type of compression spring that uses liquid and gas as the medium. It uses the principle of hydraulics to control the spring force by controlling the flow and compression of the oil.

[0049] The automotive suspension structure generally refers to the force-transmitting components that connect the vehicle frame and axles, and is an important part of ensuring ride comfort.

[0050] As an elastic element of vehicle suspension, gas springs generally require surface treatment to improve corrosion resistance. Traditional surface treatment methods are complex and time-consuming; for example, multi-layer high-temperature drying methods have been found to have poor surface treatment results, leading to coating peeling during gas spring use and failing to adequately protect the spring. The inventors of this application have discovered that oil seepage from the gas spring during heat treatment is a factor affecting surface treatment. However, due to engineering application requirements, the gas spring must be filled with oil before surface treatment, posing a challenge to the surface treatment process.

[0051] The purpose of this application is to provide a surface treatment method for gas springs, which can obtain a paint layer with high adhesion to the gas spring and good oil resistance and aging resistance using a relatively simple method.

[0052] A first aspect of this application provides a surface treatment method for a gas spring, comprising the following steps:

[0053] S100: Pre-treatment of the surface of the gas spring to remove surface grease and moisture;

[0054] S200: Apply primer to the surface of the gas spring and perform flash drying treatment;

[0055] S300: Apply topcoat to the primer surface after flash-drying and then dry it.

[0056] The raw materials of the primer, by weight, include: 11 to 13 parts epoxy resin, 5 to 7 parts xylene, 2 to 4 parts n-butanol, 0.1 to 0.2 parts hydrogenated castor oil, 0.2 to 0.4 parts dispersant, 0.1 to 0.3 parts defoamer, 0.4 to 0.6 parts leveling agent, 24 to 26 parts zinc powder, and 11 to 13 parts first curing agent.

[0057] The surface treatment method for the gas spring components provided in this application is simple. It can be achieved by flash-drying the primer and drying the topcoat. During the surface construction process, oil seepage from the gas spring can affect the surface treatment effect. Moreover, the process cost is low. The resulting coating has good adhesion to the surface of the gas spring, is not easy to fall off, has good service performance, and can play a good protective role.

[0058] In some embodiments, the flash-drying temperature in the surface treatment method for the gas spring is 20℃ to 30℃, and can also be selected from one or a range of two of the following temperatures: 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, etc. In this application, the flash-drying temperature used, especially for the surface treatment of the spring, is close to room temperature. This helps to reduce the leakage of oil contained in the gas spring assembly due to heat during the drying process of the primer, which would affect the surface treatment effect of the gas spring. Specifically, the oil leakage and mixing into the uncured paint layer would affect the adhesion between the paint layer and the surface of the gas spring assembly, ultimately leading to easy peeling of the paint layer and failure to provide good protection for the gas spring assembly.

[0059] In some embodiments, the flash-drying time in the gas spring surface treatment method is 15 min to 25 min, and can also be selected from one or a range of two of the following times: 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, etc. An appropriate flash-drying time helps improve the surface treatment efficiency of the gas spring components and reduce process costs.

[0060] In some embodiments, the drying temperature in the surface treatment method for the gas spring is 70℃ to 90℃, and can also be selected from one or a range of two of the following temperatures: 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, etc. A suitable drying temperature helps to increase the curing temperature of the paint layer while reducing the degree of oil overflow from the gas spring, resulting in a paint layer with stronger surface adhesion to the gas spring. If the drying temperature is too high, excessive oil overflow from the gas spring may occur, affecting the curing of the surface paint layer; if the temperature is too low, the curing speed of the paint layer will be slow or the obtained paint layer will be uneven.

[0061] In some embodiments, the drying time in the surface treatment method for the gas spring is 15 min to 25 min, and can also be selected from one or a range of two of the following times: 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, etc. Appropriate drying time helps improve the surface treatment efficiency of the gas spring components, reduce process costs, and also helps reduce oil seepage from the gas spring.

[0062] In some embodiments, the surface treatment method for the gas spring includes the following steps:

[0063] S100: Pre-treatment of the surface of the gas spring to remove surface grease and moisture;

[0064] S200: Apply primer to the surface of the gas spring and flash dry at 20℃~30℃ for 15min~25min;

[0065] S300: Apply a topcoat to the surface of the gas spring away from the primer that has undergone flash drying treatment, and dry it at 70℃~90℃ for 15min~25min to obtain a primer layer and a topcoat layer that are sequentially disposed on the outer surface of the gas spring.

[0066] In some embodiments, the pretreatment steps for the surface of the gas spring include flushing the gas spring assembly with a torrent, pre-degreasing, washing with water, degreasing, and washing with water.

[0067] In some embodiments, in the surface treatment method for the gas spring, the raw materials of the primer, by weight, include: 11 to 13 parts epoxy resin, 5 to 7 parts xylene, 2 to 4 parts n-butanol, 0.1 to 0.2 parts hydrogenated castor oil, 0.2 to 0.4 parts dispersant, 0.1 to 0.3 parts defoamer, 0.4 to 0.6 parts leveling agent, 24 to 26 parts zinc powder, and 11 to 13 parts first curing agent.

[0068] In some embodiments, in the surface treatment method for the gas spring, the raw materials of the topcoat, by weight, include: 54 to 56 parts of hydroxyl acrylic resin, 6 to 8 parts of propylene glycol methyl ether acetate, 24 to 26 parts of titanium dioxide, 4 to 6 parts of film-forming aid, 0.4 to 0.6 parts of leveling agent, 0.1 to 0.3 parts of defoamer, and 14 to 16 parts of second curing agent.

[0069] The primer and topcoat can achieve a paint layer with high adhesion to the surface of the gas spring components and provide good protection for the gas spring components. Using a primer with high solid content helps to reduce the difficulty of construction. The combined use of the two hardeners in the primer and topcoat also helps to reduce the construction time and curing time of the paint layer, resulting in a paint layer with high adhesion to the gas spring components.

[0070] In some embodiments, in the surface treatment method for the gas spring, the raw material of the primer, by weight, includes 11 to 13 parts of epoxy resin, which may be selected from one or two weight parts: 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, etc.

[0071] In some embodiments, in the surface treatment method for the gas spring, the raw material of the primer, by weight, includes 5 to 7 parts of xylene, and may be selected from one or a range of two weight parts: 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, etc.

[0072] In some embodiments, in the surface treatment method for the gas spring, the raw material of the primer includes 2 to 4 parts of n-butanol by weight, and may be selected from one or a range of two weight parts: 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, etc.

[0073] In some embodiments, in the surface treatment method for the gas spring, the raw material of the primer, by weight, includes 0.1 to 0.2 parts of hydrogenated castor oil, and may further be selected from the following weight ranges: 0.1 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.2 parts, etc.

[0074] In some embodiments, in the surface treatment method for the gas spring, the raw material of the primer includes 0.2 to 0.4 parts of dispersant by weight, which may be selected from one or a range of two weight parts: 0.2 parts, 0.3 parts, 0.4 parts, etc.

[0075] In some embodiments, in the surface treatment method for the gas spring, the raw material of the primer includes 0.1 to 0.3 parts of defoamer by weight, which may be selected from one or two weight parts: 0.1 parts, 0.2 parts, 0.3 parts, etc.

[0076] In some embodiments, in the surface treatment method for the gas spring, the raw material of the primer includes 0.4 to 0.6 parts by weight of leveling agent, which may be selected from one or a range of two parts by weight: 0.4 parts, 0.5 parts, 0.6 parts, etc.

[0077] In some embodiments, in the surface treatment method for the gas spring, the raw material of the primer, by weight, includes 24 to 26 parts of zinc powder, which may be selected from one or a range of two weight parts: 24 parts, 25 parts, 26 parts, etc.

[0078] In some embodiments, in the surface treatment method for the gas spring, the zinc powder in the primer is selected from 300 mesh to 500 mesh, or may be selected from 300 mesh, 400 mesh or 500 mesh.

[0079] In some embodiments, in the surface treatment method for the gas spring, the raw material of the primer includes 11 to 13 parts by weight of a first curing agent, which may be selected from one or two weight parts: 11 parts, 12 parts, 13 parts, etc.

[0080] In some embodiments, in the surface treatment method for the gas spring, the first curing agent in the topcoat is selected from biuret and its derivatives.

[0081] In some embodiments, in the surface treatment method for the gas spring, the weight ratio of the first curing agent to the epoxy resin in the primer is (0.8–1.2):1, and can also be selected from any of the following weight ratios or any range of two weight ratios: 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, etc. A suitable weight ratio of the first curing agent to the epoxy resin is beneficial to improving the curing speed of the primer and obtaining a primer layer with high adhesion to the gas spring components. If the weight ratio of the first curing agent to the epoxy resin is too high, the surface drying is too fast, causing defects in the paint film such as pinholes and blistering; if the weight ratio of the first curing agent to the epoxy resin is too low, the paint film cannot dry, causing defects in the paint film such as low corrosion resistance.

[0082] In some embodiments, in the surface treatment method for the gas spring, the viscosity of the primer composition is 60s to 90s, and may be selected from one or a range of two viscosities: 60s, 65s, 70s, 75s, 80s, 85s, 90s, etc. It is understood that the primer composition refers to the mixture of the aforementioned primer raw materials (which may also include other necessary processing, such as degassing, dehydration, drying, and settling).

[0083] In some embodiments, in the surface treatment method for the gas spring, the raw materials of the primer are mixed and then diluted again as needed before application. The application viscosity of the primer is 15s to 25s, and can be further selected from one or a range of two viscosities: 15s, 16s, 17s, 18s, 19s, 20s, 21s, 22s, 23s, 24s, 25s, etc.

[0084] Unless otherwise specified, the viscosity test method in this application is the Forecast 4 cup test, specifically GB / T1723.

[0085] In some embodiments, in the surface treatment method for the gas spring, the raw material of the topcoat, by weight, includes 54 to 56 parts of hydroxyl acrylic resin, which may be selected from one or two weight ranges: 54 parts, 54.5 parts, 55 parts, 55.5 parts, 56 parts, etc.

[0086] In some embodiments, in the surface treatment method for the gas spring, the raw material of the topcoat, by weight, includes 6 to 8 parts of propylene glycol methyl ether acetate, and may be further selected from one or a range of two weight parts: 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, etc.

[0087] In some embodiments, in the surface treatment method for the gas spring, the raw material of the topcoat includes 24 to 26 parts of titanium dioxide by weight, and may be selected from one or a range of two weight parts: 24 parts, 24.5 parts, 25 parts, 25.5 parts, 26 parts, etc.

[0088] In some embodiments, in the surface treatment method for the gas spring, the raw materials of the topcoat include 4 to 6 parts by weight of film-forming aid, which may be selected from one or a range of two parts by weight: 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, etc.

[0089] In some embodiments, in the surface treatment method for the gas spring, the raw material of the topcoat includes 0.4 to 0.6 parts by weight of leveling agent, which may be selected from one or a range of two parts by weight: 0.4 parts, 0.5 parts, 0.6 parts, etc.

[0090] In some embodiments, in the surface treatment method for the gas spring, the raw materials of the topcoat include 0.1 to 0.3 parts of defoamer by weight, which may be selected from one or two weight parts: 0.1 parts, 0.2 parts, 0.3 parts, etc.

[0091] In some embodiments, in the surface treatment method for the gas spring, the raw material of the topcoat includes 14 to 16 parts by weight of a second curing agent, which may be selected from one or a range of two weight parts: 14 parts, 15 parts, 16 parts, etc.

[0092] In some embodiments, in the surface treatment method for the gas spring, the second curing agent in the topcoat is selected from biuret and its derivatives.

[0093] In some embodiments, in the surface treatment method for the gas spring, the weight ratio of the second curing agent in the topcoat to the hydroxyl acrylic resin is (14-16):(50-60).

[0094] In some embodiments, in the surface treatment method for the gas spring, the viscosity of the topcoat composition is 15s to 25s, and may be selected from one or a range of two viscosities: 60s, 65s, 70s, 75s, 80s, 85s, 90s, etc. It is understood that the primer composition refers to the mixture of the aforementioned topcoat raw materials (which may also include other necessary processing, such as degassing, dehydration, drying, and settling).

[0095] In some embodiments, in the surface treatment method for the gas spring, after the raw materials of the topcoat are mixed, they can be diluted again as needed before application. The application viscosity of the topcoat is 15s to 25s, and can be further selected from one or a range of two viscosities: 15s, 16s, 17s, 18s, 19s, 20s, 21s, 22s, 23s, 24s, 25s, etc.

[0096] A second aspect of this application provides a gas spring, comprising a gas spring, wherein a primer layer and a topcoat layer are sequentially disposed on the outer surface of the gas spring.

[0097] The primer layer and the topcoat layer are prepared using the surface treatment method described in the first aspect.

[0098] The component surface of the gas spring provided in this application has a primer layer and a topcoat layer that are tightly bonded to it. The component of the gas spring has good surface oil resistance and aging resistance, and also helps to improve the corrosion resistance of the gas spring, thereby obtaining a longer service life and more stable operating conditions.

[0099] In some embodiments, the thickness of the primer layer in the gas spring is 15μm to 30μm.

[0100] In some embodiments, the thickness of the topcoat layer in the gas spring is 10μm to 20μm.

[0101] A third aspect of this application provides an automotive suspension structure, including the gas spring described in the second aspect.

[0102] The automotive suspension structure provided in this application includes a gas spring with a longer service life and more stable operating conditions, which is beneficial to improving the operational stability of the automotive suspension structure.

[0103] A fourth aspect of this application provides the application of the gas spring described in the second aspect or the automotive suspension structure described in the third aspect in the manufacture of a shock-absorbing structure for a vehicle. The vehicle using this gas spring or automotive suspension structure is provided in this application.

[0104] To facilitate understanding and implementation of the present invention, the following more specific and detailed embodiments and comparative examples that are easier to implement are provided for reference.

[0105] The following description, in conjunction with the accompanying drawings, further illustrates the concept, specific examples, and technical effects of the present invention to provide a full understanding of the invention. These descriptions are provided solely to aid in explaining the invention and should not be construed as limiting the scope of the claims.

[0106] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0107] Example 1

[0108] The surface treatment process for gas springs is as follows:

[0109] 1. Flood rinsing → Pre-degreasing → Water washing → Degreasing → Water washing;

[0110] 2. Primer application: The primer raw materials include 12 parts epoxy resin, 6 parts xylene, 3 parts n-butanol, 0.3 parts dispersant, 0.1 parts hydrogenated castor oil, 0.2 parts defoamer, 0.5 parts leveling agent, 25 parts 400-mesh zinc powder, and 12 parts curing agent (the formulations of the primer and topcoat can also be found in Table 1). After mixing the aforementioned primer raw materials, the viscosity of the primer composition was measured to be 72s using a Ford cup (GB / T 1723). Before applying the primer to the outer surface of the gas spring, the primer composition was diluted as needed. The solvent used for dilution does not affect the effect of the paint layer obtained by applying the primer or the adhesion to the surface of the gas spring.

[0111] 3. Flash-dry (air temperature 23℃ * 20min);

[0112] 4. Topcoat spraying: The raw materials of the topcoat include 55 parts of hydroxyl acrylic resin, 5 parts of propylene glycol methyl ether acetate, 25 parts of titanium dioxide, 5 parts of film-forming aid, 0.5 parts of leveling agent, 0.2 parts of defoamer, and 15 parts of biuret.

[0113] 5. Drying: (80℃*20min).

[0114] This process achieves good adhesion between the paint layer and the surface of the gas spring, as detailed below:

[0115] (1) When the paint layer was subjected to a direct cross-cut test, the pencil hardness was 0;

[0116] (2) After aging with a xenon lamp for 1000 hours, a cross-cut test was conducted, and the pencil hardness was grade 0.

[0117] (2) The oil spring was left to stand for 6 months in the actual working environment and no paint film peeling was observed.

[0118] Figure 1 The image shows a cross-cut test conducted on the paint layer formed on the surface of the gas spring using the method in Example 1 after aging under a xenon lamp for 1000 hours. As can be seen from the gray framed area, the paint layer was not penetrated after the cross-cut test, the metal surface was not exposed, and the paint layer did not peel off, meeting the standard of a pencil hardness of 0.

[0119] Unless otherwise specified, the cross-cut test in this application refers to GB / T 9286.

[0120] Examples 2-3

[0121] The surface treatment process for the gas springs in Examples 2 and 3 is basically the same as that in Example 1, except for the different compositions (see Table 1). The paint layer formed on the surface of the gas spring using the method in Example 1 was subjected to a cross-cut test after being aged under a xenon lamp for 1000 hours, and it met the standard of pencil hardness level 0. The surface-treated gas springs obtained in Examples 2 and 3 were left to stand for 6 months in actual working environment without any paint film peeling.

[0122] Comparative Example 1

[0123] The surface treatment process for the gas spring in Comparative Example 1 was basically the same as that in Example 1, except that the xylene in the primer composition was changed from 6 parts to 12 parts, the n-butanol from 3 parts to 5 parts, and the hydrogenated castor oil from 0.1 parts to 0.3 parts. The primer treatment was changed from flash drying at air temperature for 20 minutes to drying at 80°C for 20 minutes (the formulations of the primer and topcoat can also be found in Table 1).

[0124] The performance of the obtained paint layer deteriorates, as detailed below:

[0125] (1) When the paint layer was subjected to a direct cross-cut test, the pencil hardness was 0;

[0126] (2) After aging under a xenon lamp for 1000 hours, a cross-cut test was conducted, and the pencil hardness was grade 1.

[0127] (2) The oil spring was left to stand for 6 months in the actual working environment and the paint film peeled off.

[0128] The paint layer prepared using the method in Comparative Example 1 failed the xenon lamp aging test and also showed significant peeling after 6 months of refinement under actual working conditions. A possible reason is the increased content of solvents (xylene, n-butanol, and hydrogenated castor oil) in the primer, and the oil seepage from the gas spring during the flash-drying process (drying at 80°C for 20 minutes instead of air temperature), which affected the adhesion between the cured paint layer and the surface of the gas spring.

[0129] Figure 2 The image in the middle shows a cross-cut test conducted on the paint layer formed on the surface of the gas spring using the method of Comparative Example 1 after aging under a xenon lamp for 1000 hours. As can be seen from the white framed area, the paint layer was penetrated after the cross-cut test, exposing the metal surface, and the paint layer partially peeled off, meeting the standard of pencil hardness level 1.

[0130] Figure 3 The image in the middle shows a photograph of the paint layer formed on the surface of the gas spring using the method of Comparative Example 1, after being left to stand for 6 months in an actual working environment. As can be seen from the white framed area, the paint film has peeled off.

[0131] Comparative Example 2

[0132] The surface treatment process for the gas spring in Comparative Example 2 is basically the same as that in Example 1, except that the hydrogenated castor oil in the primer is changed from 0.1 parts to 0.3 parts, the first curing agent is changed from 12 parts to 20 parts, and the primer viscosity is changed from 88s to 57s (the formulations of the primer and topcoat can also be found in Table 1).

[0133] The results showed that the performance of the paint layer obtained in Comparative Example 2 also deteriorated, as detailed below:

[0134] (1) When the paint layer was subjected to a direct cross-cut test, the pencil hardness was 0;

[0135] (2) After aging with a xenon lamp for 1000 hours, a cross-cut test was conducted, and the pencil hardness was grade 2.

[0136] (2) The oil spring was left to stand for 6 months in the actual working environment and the paint film peeled off.

[0137] The reason for the deterioration of the paint layer in Comparative Example 2 may be the increased content of the first curing agent in the primer, the increased content of hydrogenated castor oil, and the decreased viscosity of the primer. However, after flash drying of the primer and drying treatment after applying the topcoat, it was found that the uniformity and surface smoothness of the obtained paint layer were poor. The paint layer was not resistant to external force, and its resistance to aging and oil all decreased.

[0138] Comparative Example 3

[0139] The surface treatment process for the gas spring in Comparative Example 3 is basically the same as that in Example 1, except that the flash-drying condition is changed to drying at 80°C (the formulations of the primer and topcoat can also be found in Table 1).

[0140] The results showed that the performance of the paint layer obtained in Comparative Example 3 also deteriorated, as detailed below:

[0141] (1) When the paint layer was directly cross-cut tested, the paint layer peeling was grade 0, indicating that the paint film coating was not completely dried.

[0142] (2) After aging under a xenon lamp for 1000 hours, a cross-cut test was conducted, and the pencil hardness was grade 1.

[0143] (2) The oil spring was left to stand for 6 months in the actual working environment and the paint film peeled off.

[0144] Therefore, it can be seen that the paint layer prepared using the method in Comparative Example 3 is not resistant to xenon lamp aging test, and significant peeling also occurred after 6 months of refinement under actual working conditions. The possible reason is that the primer is treated by baking instead of flash drying. This baking process not only causes oil seepage from the gas spring, but also increases the curing degree of the primer at the baking temperature. After the topcoat formulation is applied to the primer, the paint layer formed by the topcoat curing under baking conditions has poor adhesion to the primer, and the hardener in the topcoat formulation cannot penetrate into the primer, resulting in a slow film-forming reaction and an overall incomplete drying and curing of the paint layer.

[0145] Comparative Example 4

[0146] The surface treatment process for the gas spring in Comparative Example 4 is basically the same as that in Comparative Example 1. The difference is that the amount of the first curing agent in the primer is changed from 12 parts to 3.6 parts, and the amount of the second curing agent biuret in the topcoat is changed from 15 parts to 10 parts (the formulations of the primer and topcoat can also be found in Table 1).

[0147] The results showed that the performance of the paint layer obtained in Comparative Example 4 also deteriorated, as detailed below:

[0148] (1) When the paint layer was directly cross-cut tested, the paint layer peeling was grade 0, indicating that the paint film coating was not completely dried.

[0149] (2) After 1000 hours of xenon lamp aging, the paint peeling was still at level 2 after a cross-cut test.

[0150] (2) The oil spring was left to stand for 6 months in the actual working environment and the paint film peeled off.

[0151] The reason for the deterioration of the paint layer in Comparative Example 4 may be that the reduced content of the curing agent biuret in the primer after the primer has dried resulted in a slower film-forming reaction and the paint film was not completely dried, which means the film-forming performance deteriorated.

[0152] Table 1

[0153]

[0154] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0155] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. An oil-extended gas spring surface treatment method characterized by, The method comprises the following steps: carrying out pretreatment on the surface of the oil gas spring to remove grease and moisture; applying a primer on the surface of the oil gas spring and carrying out flash drying treatment; the temperature of the flash drying treatment is 15-30℃; applying a topcoat on the surface of the primer after the flash drying treatment and carrying out baking treatment; the raw materials of the primer include 11-13 parts of epoxy resin, 5-7 parts of dimethylbenzene, 2-4 parts of n-butanol, 0.1-0.2 parts of hydrogenated castor oil, 0.2-0.4 parts of dispersing agent, 0.1-0.3 parts of defoaming agent, 0.4-0.6 parts of leveling agent, 24-26 parts of zinc powder and 11-13 parts of first curing agent; the first curing agent in the raw materials of the primer is selected from biuret and its derivatives; the raw materials of the topcoat include 54-56 parts of hydroxyl acrylic resin, 6-8 parts of propylene glycol methyl ether acetate, 24-26 parts of titanium white, 4-6 parts of film-forming aid, 0.4-0.6 parts of leveling agent, 0.1-0.3 parts of defoaming agent and 14-16 parts of second curing agent; the second curing agent in the raw materials of the topcoat is selected from biuret and its derivatives.

2. The oil-extended gas spring surface treatment method according to claim 1, characterized by, the time of the flash drying treatment is 15-25 min.

3. The oil-extended gas spring surface treatment method according to claim 1 or 2, characterized by, one or more of the following conditions are met: (1) the temperature of the baking treatment is 70-90℃; (2) the time of the baking treatment is 15-25 min.

4. The oil-extended gas spring surface treatment method according to claim 1, characterized by, the mesh number of the zinc powder in the raw materials of the primer is selected from 300-500.

5. The oil-extended spring surface treatment method according to claim 1, wherein the weight ratio of the first curing agent to the epoxy resin in the raw materials of the primer is (0.8-1.2):

1.

6. The oil-extended spring surface treatment method according to claim 1, wherein the weight ratio of the second curing agent to the hydroxyl acrylic resin in the raw materials of the topcoat is (14-16):(50-60).

7. An oil-impregnated gas spring, characterized by the oil gas spring and the primer coating and the topcoat coating arranged on the outer surface of the oil gas spring in sequence; the primer coating and the topcoat coating are prepared by the surface treatment method described in any one of claims 1-6.

8. The oil-impregnated gas spring of claim 7, wherein, the thickness of the primer coating of the oil gas spring is 15-30 μm and the thickness of the topcoat coating is 10-20 μm.

9. An automobile suspension structure characterized by comprising: the oil gas spring filled with oil as described in claim 7 or 8.

10. The use of the oil-filled oil gas spring as described in claim 7 or 8 or the automobile suspension structure as described in claim 9 in the manufacture of shock-absorbing structure of vehicles.

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