Application method of sand streak wax in industrial coating
Through the multi-layer structure of sand wax and curing temperature adjustment, the problems of complex formula and narrow construction window of traditional sand paint are solved, and the formulation design and stable sand texture effect are achieved. It is suitable for a variety of coating materials.
Patent Information
- Application Number
- CN202510698007.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-28
- Publication Date
- 2025-07-25
AI Technical Summary
The design of traditional sand-form coatings is complex and the construction window is narrow, resulting in a narrow application range and low yield rate.
The sand wax with multi-layer structure is adopted, including high melting point, medium melting point and low melting point wax layers. By adjusting the curing temperature, the sand texture effect can be controlled, and the texture adjustment from rough to extremely delicate is achieved, with the addition amount range of 1% to 10%.
Simplify formula design, reduce construction sensitivity, achieve stable sand texture effect, adapt to a variety of coating main materials and formula systems, and improve production stability and coating performance.
Smart Images
Figure CN120365781A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of coating additives, and particularly relates to an application method of sand pattern wax in industrial coatings. Background Art
[0002] A texturizing agent is an auxiliary agent that can provide a structural effect with uniform surface texture, gloss, and color for the coating surface. When in use, some insoluble or incompatible additives are often added to control the particle size, melting viscosity, and surface tension of the molten surface of the powder, so as to achieve the desired texture effect. Textured coatings are a general term and have different varieties, such as sand pattern type, wrinkle type, water pattern type, and so on.
[0003] Sand pattern industrial coatings with a texture effect similar to sand grains on the surface are widely used in the home appliance, furniture, building material, automotive industry, and other metal product industries because of their high decorative property, which can cover the defects on the substrate surface and improve the appearance quality of the product. Sand pattern industrial coatings are generally prepared by adding a low-polarity sand pattern agent to industrial coatings. During the melting, leveling, and curing flow processes, the base material with high surface tension wraps the sand pattern agent with low surface tension, making the coating film present a uniformly distributed sand grain shape.
[0004] At present, one of the methods for preparing sand pattern coatings is to add incompatible substances. For example, Patent CN108359033 prepared a high molecular weight polyethylene sand pattern wax, and the texturing additive in Patent CN107532014 is polytetrafluoroethylene. However, the existing technology has the following limitations: In order to obtain different sand pattern effects, specific selection needs to be made according to the characteristics of the main coating material, the formula substances, the thickness of the coating, etc., and the addition amount of the sand pattern agent needs to be accurately controlled to ensure that both a stable sand pattern effect can be formed and other properties of the coating are not affected. This increases the complexity of the formula design and requires strict control of construction conditions, such as spraying environment, curing temperature, and time, etc., to ensure that the incompatible substances can play their roles correctly and form the expected sand pattern effect. These limitations lead to problems such as narrow application range and low yield rate of existing sand pattern coatings. Summary of the Invention
[0005] Technical Problem
[0006] The present invention aims to provide an application method of sand pattern wax in industrial coatings to solve the problems of complex formula design and narrow construction window of traditional sand pattern coatings.
[0007] Technical Solution
[0008] The first aspect of the present invention provides an application method of sand pattern wax in industrial coatings, including the following steps: 1) uniformly mixing the sand pattern wax with the industrial coating to obtain a coating composition; 2) diluting the coating composition with a low-viscosity solvent and then uniformly spraying it on the surface of the substrate to form a coating; 3) performing a leveling treatment on the coating at room temperature; 4) performing a curing treatment on the leveled coating; wherein, the sand pattern wax has a multi-layer structure, which sequentially includes from the inside to the outside: a high-melting-point wax layer, a medium-melting-point wax layer, and a low-melting-point wax layer with melting point ranges of 200-350°C, 120-200°C, and 50-120°C respectively; the high-melting-point wax layer, the medium-melting-point wax layer, and the low-melting-point wax layer are combined through a molten interface; wherein, the sand pattern effect is controlled by adjusting the curing temperature: when rough sand patterns are required, the curing temperature is lower than the melting point of the low-melting-point wax layer; when medium sand patterns are required, the curing temperature is higher than the melting point of the low-melting-point wax layer but lower than the melting point of the medium-melting-point wax layer; when delicate sand patterns are required, the curing temperature is higher than the melting point of the medium-melting-point wax layer but lower than the melting point of the high-melting-point wax layer; when extremely delicate sand patterns are required, the curing temperature is higher than the melting point of the high-melting-point wax layer.
[0009] In some embodiments, the curing temperature is preferably 5-15°C higher than the melting point of the target wax layer.
[0010] In some embodiments, the addition amount of the sand pattern wax is 1% - 10% of the total mass of the industrial coating.
[0011] In some embodiments, no additional sand pattern agent and wax additive are added to the industrial coating. When the industrial coating itself contains a sand pattern agent and a wax additive, further adding the sand pattern wax of the present invention can further adjust the sand pattern effect; when the industrial coating does not contain a sand pattern agent and a wax additive, using the sand pattern wax of the present invention can replace the sand pattern agent / wax additive to achieve the sand pattern effect, so there is no need to add additional sand pattern agent and wax additive.
[0012] In some embodiments, the film thickness of the cured coating is 30-50μm.
[0013] In some embodiments, the high-melting-point wax layer uses polytetrafluoroethylene wax; the medium-melting-point wax layer uses any one of high-density oxidized polyethylene wax, polypropylene wax, polyamide wax, or oxidized polyethylene wax; the low-melting-point wax layer uses any one of carnauba wax, low-density oxidized polyethylene wax, paraffin wax, microcrystalline wax, beeswax, montan wax, or Fischer-Tropsch wax.
[0014] In some embodiments, the thicknesses of the high-melting-point wax layer, the medium-melting-point wax layer, and the low-melting-point wax layer respectively account for 20% - 30%, 50% - 60%, and 10% - 20% of the total thickness of the sand pattern wax.
[0015] In some embodiments, the DV90 particle size of the sand pattern wax is 20-45μm.
[0016] In some embodiments, the difference between the melting point of the medium melting point wax layer and the melting point of the high melting point wax layer is ≥50 °C, and the difference between the melting point of the low melting point wax layer and the melting point of the medium melting point wax layer is ≥30 °C.
[0017] In some embodiments, the surface roughness of the cured coating is 0.2 - 30 Ra / μm, the pencil hardness is ≥2H, and the positive impact strength is ≥50 cm.
[0018] In some embodiments, the low viscosity solvent in step 2) is deionized water; the time of the leveling treatment in step 3) is 10 - 20 min; the curing treatment method in step 4) is baking.
[0019] Technical effects
[0020] 1. The application method provided by the present invention has high versatility. The sand pattern wax can be adapted to a variety of coating main materials and formulation systems, without the need for specific selection for different materials, significantly reducing the complexity of formula design.
[0021] 2. The present invention simplifies the control of the addition amount. A stable sand pattern effect can be formed within a relatively wide addition amount range (such as 1% - 10%), avoiding problems such as uneven texture or performance degradation caused by deviation of the addition amount.
[0022] 3. The construction conditions have strong fault tolerance. Different sand pattern effects can be achieved directly by adjusting the curing conditions. The construction sensitivity is reduced, allowing a more relaxed process window and improving production stability.
[0023] 4. Adding the sand pattern agent used in the application method can achieve the effects of both the sand pattern agent and the wax additive in traditional sand pattern coatings. Brief description of the drawings
[0024] Figure 1 It is a schematic diagram of the sand pattern wax structure. Detailed implementation manners
[0025] For the convenience of reviewing the technical solutions of the application, the following first gives a general description and definition of the terms and expressions involved in the present application.
[0026] The term "comprising", "including" or any other variant thereof is intended to cover non - exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or also elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.
[0027] The particle size Dv90 refers to the particle size value corresponding to the cumulative distribution percentage of 90% from small to large in the particle size distribution.
[0028] For the hardness of pencils, B means soft, H means hard, and HB means medium. For the hardness grades H1 - H6, the larger the number, the harder the pencil and the lighter the color. For the softness grades B1 - B6, the larger the number, the softer the pencil and the darker the color.
[0029] The density of high - density oxidized polyethylene wax is 0.94 - 0.98 g / cm 3 。
[0030] The density of low - density oxidized polyethylene wax is 0.91 - 0.93 g / cm 3 。
[0031] The test method for the roughness of the coating described in the present invention is carried out with reference to JIS B 0601 - 2013.
[0032] The test method for the pencil hardness of the coating is carried out with reference to GB / T 6739 - 2022.
[0033] The test method for the impact performance of the coating is determined with reference to T / GDTL 004 - 2019.
[0034] Process conditions for preparing wax micro - powder by supercritical CO2 melt spraying: According to the melting points of different waxes, select appropriate temperature and pressure, completely dissolve the wax raw material in supercritical CO2, and then quickly depressurize and spray it out through a nozzle to obtain micro - powder.
[0035] In each group of comparative experiments provided in this application, unless otherwise specified, except for the differences pointed out in each group, other experimental conditions, materials, etc. are kept consistent for comparability.
[0036] The reagents and instrument equipment used in the embodiments of the present invention can be purchased from the market without detailed description.
[0037] The following further describes a sand - pattern wax and its preparation method and application provided by this application.
[0038] Preparation of sand - pattern wax in Example 1
[0039] The structure of the sand - pattern wax is as Figure 1 shown. The preparation method of the sand - pattern wax includes the following steps:
[0040] S1. Prepare the first wax micro - powder from high - melting - point wax raw material by supercritical CO2 melt spraying method;
[0041] S2. Mix the medium - melting - point wax raw material and the first wax micro - powder evenly by a twin - screw extruder, press the extruded sheet into a tablet, and then prepare the second wax micro - powder by supercritical CO2 melt spraying method;
[0042] S3. Mix the low-melting-point wax raw material and the second wax micropowder evenly by a twin-screw extruder, press the extruded sheet material, and then prepare the third wax micropowder by the supercritical CO2 melting spray method to obtain the sand pattern wax.
[0043] Among them, the high-melting-point wax in step S1 is polytetrafluoroethylene wax (melting point 230 °C), and the particle size DV90 of the first wax micropowder is 8 μm detected by a laser particle size analyzer; the medium-melting-point wax in step S2 is high-density oxidized polyethylene wax (melting point 140 °C), and the particle size DV90 of the second wax micropowder is 29.5 μm detected by a laser particle size analyzer; the low-melting-point wax in step S3 is carnauba wax (melting point 85 °C), and the particle size DV90 of the third wax micropowder is 37 μm detected by a laser particle size analyzer.
[0044] Preparation of the sand pattern wax in Example 2
[0045] The difference from Example 1 is that: the high-melting-point wax in step S1 is polytetrafluoroethylene wax (melting point 230 °C), the particle size DV90 of the first wax micropowder is 8 μm detected by a laser particle size analyzer, the medium-melting-point wax in step S2 is high-density oxidized polyethylene wax (melting point 140 °C), the particle size DV90 of the second wax micropowder is 23 μm detected by a laser particle size analyzer, the low-melting-point wax in step S3 is carnauba wax (melting point 85 °C), and the particle size DV90 of the third wax micropowder is 28 μm detected by a laser particle size analyzer.
[0046] Preparation of the sand pattern wax in Example 3
[0047] The difference from Example 1 is that: the high-melting-point wax in step S1 is polytetrafluoroethylene wax (melting point 230 °C), the particle size DV90 of the first wax micropowder is 8 μm detected by a laser particle size analyzer, the medium-melting-point wax in step S2 is high-density oxidized polyethylene wax (melting point 140 °C), the particle size DV90 of the second wax micropowder is 24 μm detected by a laser particle size analyzer, the low-melting-point wax in step S3 is carnauba wax (melting point 85 °C), and the particle size DV90 of the third wax micropowder is 28 μm detected by a laser particle size analyzer.
[0048] Preparation of the sand pattern wax in Example 4
[0049] The difference from Example 1 is that: the high-melting-point wax in step S1 is polytetrafluoroethylene wax (melting point 230 °C), the particle size DV90 of the first wax micropowder is 8 μm detected by a laser particle size analyzer, the medium-melting-point wax in step S2 is high-density oxidized polyethylene wax (melting point 140 °C), the particle size DV90 of the second wax micropowder is 24 μm detected by a laser particle size analyzer, the low-melting-point wax in step S3 is low-density oxidized polyethylene wax (melting point 100 °C), and the particle size DV90 of the third wax micropowder is 28 μm detected by a laser particle size analyzer.
[0050] Preparation of Sand Pattern Wax in Example 5
[0051] The difference from Example 1 is that the high melting point wax in step S1 is polytetrafluoroethylene wax (melting point 210°C), and the DV90 of the particle size of the first wax fine powder detected by a laser particle size analyzer is 8 μm; the medium melting point wax in step S2 is polypropylene wax (melting point 150°C), and the DV90 of the particle size of the second wax fine powder detected by a laser particle size analyzer is 24 μm; the low melting point wax in step S3 is low density oxidized polyethylene wax (melting point 110°C), and the DV90 of the particle size of the third wax fine powder detected by a laser particle size analyzer is 28 μm.
[0052] Preparation of Sand Pattern Wax in Example 6
[0053] The difference from Example 1 is that the high melting point wax in step S1 is polytetrafluoroethylene wax (melting point 210°C), and the DV90 of the particle size of the first wax fine powder detected by a laser particle size analyzer is 8 μm; the medium melting point wax in step S2 is polypropylene wax (melting point 140°C), and the DV90 of the particle size of the second wax fine powder detected by a laser particle size analyzer is 24 μm; the low melting point wax in step S3 is polyethylene wax (melting point 110°C), and the DV90 of the particle size of the third wax fine powder detected by a laser particle size analyzer is 28 μm.
[0054] Preparation of Sand Pattern Wax in Example 7
[0055] The difference from Example 1 is that the high melting point wax in step S1 is polytetrafluoroethylene wax (melting point 210°C), and the DV90 of the particle size of the first wax fine powder detected by a laser particle size analyzer is 8 μm; the medium melting point wax in step S2 is polypropylene wax (melting point 140°C), and the DV90 of the particle size of the second wax fine powder detected by a laser particle size analyzer is 24 μm; the low melting point wax in step S3 is carnauba wax (melting point 110°C), and the DV90 of the particle size of the third wax fine powder detected by a laser particle size analyzer is 28 μm.
[0056] Preparation of Sand Pattern Wax in Example 8
[0057] The difference from Example 1 is that the high melting point wax in step S1 is polytetrafluoroethylene wax (melting point 200°C), and the DV90 of the particle size of the first wax fine powder detected by a laser particle size analyzer is 8 μm; the medium melting point wax in step S2 is polyamide wax (melting point 150°C), and the DV90 of the particle size of the second wax fine powder detected by a laser particle size analyzer is 24 μm; the low melting point wax in step S3 is carnauba wax (melting point 80°C), and the DV90 of the particle size of the third wax fine powder detected by a laser particle size analyzer is 28 μm.
[0058] Preparation of Sand Pattern Wax in Example 9
[0059] The differences from Example 1 are as follows: The high melting point wax in step S1 is polytetrafluoroethylene wax (melting point 200°C). The DV90 of the particle size of the first wax fine powder detected by a laser particle size analyzer is 8 μm. The medium melting point wax in step S2 is high density oxidized polyethylene wax (melting point 130°C). The DV90 of the particle size of the second wax fine powder detected by a laser particle size analyzer is 24 μm. The low melting point wax in step S3 is polyethylene wax (melting point 100°C). The DV90 of the particle size of the third wax fine powder detected by a laser particle size analyzer is 28 μm.
[0060] Comparative Example 1
[0061] The raw material is polytetrafluoroethylene wax (melting point 230°C), which is made into wax fine powder. The DV90 of the particle size of this wax fine powder detected by a laser particle size analyzer is 28 μm.
[0062] Comparative Example 2
[0063] The raw material is polypropylene wax (melting point 170°C), which is made into wax fine powder. The DV90 of the particle size of this wax fine powder detected by a laser particle size analyzer is 28 μm.
[0064] Comparative Example 3
[0065] The raw material is polyethylene wax (melting point 120°C), which is made into wax fine powder. The DV90 of the particle size of this wax fine powder detected by a laser particle size analyzer is 28 μm.
[0066] Comparative Example 4
[0067] The high melting point wax in step S1 is polytetrafluoroethylene wax (melting point 230°C). The DV90 of the particle size of S1 detected by a laser particle size analyzer is 8 μm. The medium melting point wax in step S2 is polyamide wax (melting point 150°C). The DV90 of the particle size of the second wax fine powder detected by a laser particle size analyzer is 28 μm.
[0068] Comparative Example 5
[0069] The high melting point wax in step S1 is polytetrafluoroethylene wax (melting point 230°C). The DV90 of the particle size of S1 detected by a laser particle size analyzer is 8 μm. There is no substance in the medium melting point wax layer in step S2. The low melting point wax in step S3 is polyethylene wax (melting point 120°C). The DV90 of the particle size of the third wax fine powder detected by a laser particle size analyzer is 28 μm.
[0070] Comparative Example 6
[0071] The high melting point wax in step S1 is polytetrafluoroethylene wax (melting point 230°C). The DV90 of the particle size of S1 detected by a laser particle size analyzer is 8 μm.
[0072] The types and parameters of the raw materials in Examples 1 - 9 and Comparative Examples 1 - 6 are shown in Table 1.
[0073] Table 1 Types and Parameters of Sand Pattern Wax Raw Materials
[0074]
[0075]
[0076] Note: The particle size mentioned refers to the particle sizes of the first wax micro-powder, the second wax micro-powder and the sand pattern wax prepared respectively according to the steps.
[0077] First, to test the application of the sand pattern wax prepared in the examples and comparative examples of the present invention in actual industrial coatings, the sand pattern waxes prepared in Examples 1-9 and Comparative Examples 1-6 were applied to conventional industrial coatings (Coating System 1) to test the coating properties, as shown in Examples 10-15. Then, to prove that the sand pattern wax prepared by the present invention can be adapted to a variety of coating main materials and formulation systems, the same batch of sand pattern wax (Example 5) prepared in this application was applied to different industrial coatings (Coating Systems 1-3), and compared with Coating Systems 4 and 6 containing sand pattern agents and Coating System 5 containing wax additives (low-density oxidized polyethylene wax powder), as shown in Example 16. The specific component compositions of Coating Systems 1-6 are shown in Table 2.
[0078] Table 2 Component Compositions of Different Coating Systems
[0079]
[0080] Application of the Sand Pattern Wax in Example 10 to Industrial Coatings
[0081] The sand pattern waxes of Examples 1-9 and Comparative Examples 1-6 were taken respectively. The mass percentage of the sand pattern wax in the total coating system was 5%. After being mixed evenly with other components in Coating System 1, an appropriate amount of deionized water was added to dilute to a suitable viscosity and then spray-coated. After leveling for 15 min, it was baked at 80 °C for 60 min, and the roughness, pencil hardness and impact resistance of the coating were tested, as shown in Table 2.
[0082] Table 3 Coating Property Test Data of the Sand Pattern Wax under the Curing Conditions of 80 °C with an Addition Amount of 5%
[0083]
[0084]
[0085] Application of the Sand Pattern Wax in Example 11 to Industrial Coatings
[0086] Take the sand pattern waxes of Examples 1-9 and Comparative Examples 1-6 respectively. The mass percentage of the sand pattern wax in the total coating system is 5%. After mixing it evenly with other components in Coating System 1, add an appropriate amount of deionized water to dilute it to a suitable viscosity and then spray for construction. After leveling for 15 minutes, bake at 130 °C for 15 minutes, and test the roughness, pencil hardness and impact resistance of the coating, as shown in Table 3.
[0087] Table 4 Test data of coating properties under the curing condition of 130 °C with 5% addition amount of sand pattern wax
[0088]
[0089] Application of Sand Pattern Wax in Industrial Coatings in Example 12
[0090] Take the sand pattern waxes of Examples 1-9 and Comparative Examples 1-6 respectively. The mass percentage of the sand pattern wax in the total coating system is 5%. After mixing it evenly with other components in Coating System 1, add an appropriate amount of deionized water to dilute it to a suitable viscosity and then spray for construction. After leveling for 15 minutes, bake at 185 °C for 5 minutes, and test the roughness, pencil hardness and impact resistance of the coating, as shown in Table 4.
[0091] Table 5 Test data of coating properties under the curing condition of 185 °C with 5% addition amount of sand pattern wax
[0092]
[0093]
[0094] Application of Sand Pattern Wax in Industrial Coatings in Example 13
[0095] Take the sand pattern waxes of Examples 1-9 and Comparative Examples 1-6 respectively. The mass percentage of the sand pattern wax in the total coating system is 5%. After mixing it evenly with other components in Coating System 1, add an appropriate amount of deionized water to dilute it to a suitable viscosity and then spray for construction. After leveling for 15 minutes, bake at 240 °C for 5 minutes, and test the roughness, pencil hardness and impact resistance of the coating, as shown in Table 5.
[0096] Table 6 Test data of coating properties under the curing condition of 240 °C with 5% addition amount of sand pattern wax
[0097]
[0098] Application of Sand Pattern Wax in Industrial Coatings in Example 14
[0099] Respectively take the sand pattern waxes of Examples 1-9 and Comparative Examples 1-6. The mass percentage of the sand pattern wax in the total coating system is 1%. After mixing evenly with other components in Coating System 1, add an appropriate amount of deionized water to dilute to a suitable viscosity and then spray for construction. After leveling for 15 minutes, bake at 130°C for 15 minutes, and test the roughness, pencil hardness and impact resistance of the coating, as shown in Table 6.
[0100] Table 7 Coating performance test data when the addition amount of sand pattern wax is 1% under the curing condition of 130°C
[0101]
[0102] Application of Sand Pattern Wax in Industrial Coatings in Example 15
[0103] Respectively take the sand pattern waxes of Examples 1-9 and Comparative Examples 1-6. The mass percentage of the sand pattern wax in the total coating system is 10%. After mixing evenly with other components in Coating System 1, add an appropriate amount of deionized water to dilute to a suitable viscosity and then spray for construction. After leveling for 15 minutes, bake at 130°C for 15 minutes, and test the roughness, pencil hardness and impact resistance of the coating, as shown in Table 7.
[0104] Table 8 Coating performance test data when the addition amount of sand pattern wax is 10% under the curing condition of 130°C
[0105]
[0106] It can be seen from the coating performance test data of Examples 1-9 and Comparative Examples 1-6 recorded in Table 2 and Table 7 that the sand pattern wax of the present invention can form a stable sand pattern effect within the range of 1% to 10% addition amount. Among them, the comprehensive performance is the best when the addition amount is 5%: the pencil hardness ≥ 2H (reaching 4H in some working conditions), and the positive impact strength ≥ 50 cm passes; although the roughness is slightly lower at a low addition amount (1%), the hardness and impact performance remain good; no uneven texture or performance decline occurs at a high addition amount (10%).
[0107] In addition, it can also be seen from the table that when the curing temperature is lower than the melting point of the low-melting-point wax layer (such as 80 °C), the coating roughness is the highest (Ra 12.34 - 22.16 μm), presenting a rough sand pattern; when it is between the melting points of the low-melting-point and medium-melting-point wax layers (such as 130 °C), the roughness drops to Ra 5.94 - 14.37 μm, forming a medium sand pattern; when it is between the melting points of the medium-melting-point and high-melting-point wax layers (such as 185 °C), the roughness drops to Ra 1.99 - 2.77 μm, presenting a delicate sand pattern; when it is higher than the melting point of the high-melting-point wax layer (such as 240 °C), the roughness is the lowest (Ra 0.51 - 0.98 μm), presenting an extremely delicate sand pattern or no distinct particle texture. This indicates that the present invention can achieve the regulation of the full-gradient sand pattern effect from rough to extremely delicate by precisely controlling the relative relationship between the curing temperature and the melting points of each layer of wax. Compared with the comparative examples (single wax layer or lack of intermediate layer), the sand pattern wax with a three-layer structure designed by the present invention has significant advantages: the roughness of the three-layer sand pattern wax in the examples is more uniform under the same conditions, and the pencil hardness and impact resistance are better, reflecting the improvement of the comprehensive performance of the coating by the multi-layer melting point gradient design.
[0108] Application of the sand pattern wax of Example 16 in various industrial coating systems
[0109] Take the sand pattern wax of Example 5 and mix it evenly with other components in Coatings 1 - 3 respectively. After diluting the coating systems 1 - 3 mixed with the sand pattern wax of the present invention and the coating systems 4 - 6 for comparison with an appropriate amount of deionized water to a suitable viscosity, spray and construct. After leveling for 15 min, bake at 130 °C for 15 min, and test the roughness, pencil hardness and impact resistance of the coating, as shown in Table 8.
[0110] Table 9 Coating performance test data of different systems with sand pattern wax added under the curing condition of 130 °C
[0111]
[0112] The data in Table 9 show that when the sand pattern wax of the present invention is applied to different coating systems, under the curing condition of 130 °C, each film thickness shows an appropriate medium sand pattern effect (Ra 7.2 - 8.5 μm), as well as excellent high hardness (3H) and impact resistance (passing the forward impact), which is significantly better than the traditional sand pattern agent system (Coating System 6). Although the effects of Coating System 4 and Coating System 3 are equivalent in terms of roughness, pencil hardness and impact performance tests, the film appearance of System 3 is more delicate and uniform than that of System 4 by visual observation. It shows that the sand pattern wax of the present invention can replace the traditional sand pattern agents (Coating Systems 4 and 6) or wax additives (Coating System 5), and has broad applicability.
[0113] The above specific implementation manners have further elaborated in detail the object, technical solution and beneficial effects of the present application. It should be understood that the above are only the specific implementation manners of the present application and are not used to limit the protection scope of the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solution of the present application shall be included within the protection scope of the present application.
Claims
1. A method for applying sand-grain wax in industrial coatings, characterized in that, It includes the following steps: 1) Uniformly mix the sand pattern wax with the industrial coating to obtain a coating composition; 2) After diluting the coating composition with a low-viscosity solvent, uniformly spray it on the surface of the substrate to form a coating; 3) Level the coating at room temperature; 4) Cure the leveled coating; Among them, the sand pattern wax has a multi-layer structure, which sequentially includes from the inside to the outside: a high-melting-point wax layer, a medium-melting-point wax layer, and a low-melting-point wax layer with melting point ranges of 200-350°C, 120-200°C, and 50-120°C respectively; the high-melting-point wax layer, the medium-melting-point wax layer, and the low-melting-point wax layer are combined through a molten interface; Among them, the sand pattern effect is controlled by adjusting the curing temperature: when rough sand pattern is required, the curing temperature is lower than the melting point of the low-melting-point wax layer; when medium sand pattern is required, the curing temperature is higher than the melting point of the low-melting-point wax layer but lower than the melting point of the medium-melting-point wax layer; when delicate sand pattern is required, the curing temperature is higher than the melting point of the medium-melting-point wax layer but lower than the melting point of the high-melting-point wax layer; when extremely delicate sand pattern is required, the curing temperature is higher than the melting point of the high-melting-point wax layer.
2. The application method according to claim 1, wherein The addition amount of the sand pattern wax is 1% - 10% of the total mass of the industrial coating.
3. The application method according to claim 1, wherein No additional sand pattern agent and wax additive are added to the industrial coating.
4. The application method according to claim 1, wherein The film thickness of the cured coating is 30 - 50μm.
5. The application method according to claim 1, wherein, The high-melting-point wax layer uses polytetrafluoroethylene wax; the medium-melting-point wax layer uses any one of high-density oxidized polyethylene wax, polypropylene wax, polyamide wax, or oxidized polyethylene wax; the low-melting-point wax layer uses any one of carnauba wax, low-density oxidized polyethylene wax, paraffin wax, microcrystalline wax, beeswax, montan wax, or Fischer-Tropsch wax.
6. The application method according to claim 1, wherein The thicknesses of the high-melting-point wax layer, the medium-melting-point wax layer, and the low-melting-point wax layer respectively account for 20% - 30%, 50% - 60%, and 10% - 20% of the total thickness of the sand pattern wax.
7. The application method according to claim 1, wherein The particle size DV90 of the sand pattern wax is 20 - 45μm.
8. The application method according to claim 1, characterized in that, The difference between the melting point of the medium-melting-point wax layer and the melting point of the high-melting-point wax layer is ≥50°C, and the difference between the melting point of the low-melting-point wax layer and the melting point of the medium-melting-point wax layer is ≥30°C.
9. The application method according to claim 1, characterized in that The surface roughness of the cured coating is 0.2 - 30Ra / μm, the pencil hardness is ≥2H, and the positive impact strength is ≥50cm.
10. The application method according to claim 1, wherein, In step 2), the low-viscosity solvent is deionized water; in step 3), the leveling time is 10 - 20min; in step 4), the curing method is baking.