Water-based conductive primer-topcoat coating for plastic base material and application of water-based conductive primer-topcoat coating

Abstract

The invention relates to a water-based conductive primer-topcoat coating for a plastic substrate. The coating is prepared from a plurality of raw materials such as a water-based polyolefin emulsion, a water-based inorganic lithium silicate modified pure acrylate multipolymer self-crosslinking emulsion, a dispersing agent, a neutralizing agent and a thickening agent. The water-based polyolefin emulsion is used as matrix resin, and a coating film and plastic have excellent adhesive force; a coating film of the water-based inorganic lithium silicate modified pure acrylate multipolymer self-crosslinking emulsion has better dry rate, hardness, weather resistance and various liquid medium resistance; by adding a small amount of hydroxyl multi-arm carbon nanotubes, a carboxyl multi-arm carbon nanotube conductive material coating film has conductivity; and by adding the silica powder, the coating film has excellent hardness and heat and humidity resistance. According to the invention, the waterborne property of the conductive primer-topcoat coating for the plastic substrate is realized, the general adhesive force of PP, PC and ABS is excellent, the conductivity of a coating film is realized by using a multi-arm carbon nanotube material for the first time, and the resistance value of the coating film is below 104 omega.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings for plastic parts and production processes, and relates to a water-based conductive bottom-and-top all-in-one coating for a plastic substrate composed of a water-based polyolefin emulsion, a water-based inorganic lithium silicate-modified pure acrylate multi-polymer self-crosslinking emulsion, a multi-arm carbon nanotube conductive material, a pigment, and a filler, and a preparation method thereof. Background Art

[0002] At present, most of the plastic parts in my country are still painted with traditional solvent-based paints. With the gradual and strict control of environmental protection laws and regulations, it is imperative to use water-based systems for plastic parts painting. Water-based paints have strict requirements on construction technology and must have good coating process conditions. Therefore, it is necessary to build a production line suitable for water-based plastic coatings. This also means that the coating production of plastic parts will inevitably be centralized and scaled in the future. The present invention is a kind of water-based conductive bottom-to-bottom coating for plastic substrates. Under the premise of meeting the requirements of environmental protection laws and regulations, the water-based coating film of plastic substrates PP, PC, and ABS has excellent electrostatic conductivity. It is a pure water-based coating that does not contain any organic solvents. The present invention mainly eliminates static electricity for military plastic equipment and provides durable protection in complex and harsh outdoor environments.

[0003] The use of water-based polyolefin emulsion can ensure good adhesion between the primer and the plastic substrate.

[0004] A water-based inorganic lithium silicate-modified pure acrylic ester multi-polymer self-crosslinking emulsion is selected to improve hardness, water resistance, weather resistance and other medium resistance properties.

[0005] By adding multi-arm carbon nanotube conductive materials, a conductive base and surface integrated paint film with excellent conductive properties is achieved.

[0006] The product is further optimized by adding silica powder, which improves the hardness and moisture and heat resistance. Summary of the invention

[0007] The purpose of the present invention is to realize the water-based conductive bottom-surface integrated coating for plastic substrates, ensure good matching performance with plastic substrates, and electrostatic spraying is also possible due to the conductive performance of the paint film. The coating is composed of water-based polyolefin emulsion, water-based inorganic lithium silicate modified pure acrylate multi-copolymer self-crosslinking emulsion, dispersant, neutralizer, thickener, pigment, multi-arm carbon nanotube conductive material, and silicon powder.

[0008] To achieve the above purpose, the present invention discloses the following technical contents: A water-based conductive primer-and-surface all-in-one coating for a plastic substrate, characterized in that the coating is composed of the following raw materials in parts by weight: Main raw material ratio (1) Preparation of conductive slurry Deionized water 50 Wetting and dispersing agent TEGO 750W 40 Hydroxyl multi-arm carbon nanotubes CNT202 5 Carboxyl multi-arm carbon nanotubes CNT302 5 (2) Preparation of pigment and filler slurry Deionized water 50 Wetting and dispersing agent TEGO 750W 10 U Carbon Black 10 Silicon powder 1250 mesh 30 (3) Dilution of thickener Thickener AP-16 50 Deionized water 50 (4) Harmony Water-based polyolefin emulsion BW5800 40-50 Dimethylethanolamine 0.1-0.2 Deionized water 10-15 Waterborne inorganic lithium silicate modified pure acrylate Multi-polymer self-crosslinking emulsion AS-86H2 5-10 Main raw material ratio (1) Dispersed conductive water slurry 4-8 Main raw material ratio (2) Dispersed pigment and filler water slurry 15-20 Deionized water 5-10 Main raw material ratio (3) diluted thickener AP-16 0.2-0.5 Description of the above ingredients: The water-based polyolefin emulsion is BW5800 from Mitsubishi Chemical Corporation, the water-based inorganic lithium silicate modified pure acrylate multi-copolymer self-crosslinking emulsion is AS-86H2 from Jingzhou Aishi Environmental Protection New Materials, the hydroxyl multi-arm carbon nanotube conductive material is CNT202 from Beijing Dekedaojin Technology Co., Ltd., the carboxyl multi-arm carbon nanotube conductive material is CNT302 from Beijing Dekedaojin Technology Co., Ltd., the wetting and dispersing agent is Tego750W from Digo, the carbon black is U carbon black from Orion, the silicon micropowder is 1250 mesh silicon micropowder from Chuzhou Ge Rui, the thickener is AP-16 from Mingling, and the amine neutralizer is dimethylethanolamine from Yangzi Petrochemical.

[0009] The present invention further discloses a method for preparing a water-based conductive primer-and-surface coating for a plastic substrate, which is characterized by the following steps: (1) Preparation of conductive slurry Add deionized water to a stainless steel basin, stir at a low speed of 300-500 rpm, then add a wetting and dispersing agent Digo 750W and stir for 10 minutes, add hydroxyl multi-arm carbon nanotube nanotubes CNT202 and carboxyl multi-arm carbon nanotube nanotubes CNT302, then switch to a high speed of 800-1000 rpm and stir for 30 minutes, use a sand mill to grind and disperse until the color paste fineness is less than 20 μm, then filter out for use; (2) Preparation of pigment and filler slurry Add deionized water to a stainless steel basin, stir at a low speed of 300-500 rpm, add the wetting and dispersing agent Digo 750W and stir for 10 minutes, then switch to a high speed of 800-1000 rpm, add U carbon black, add 1250 mesh silica powder, stir for 30 minutes, use a sand mill to grind and disperse until the color paste fineness is less than 20μm, then filter it out for use; (3) Dilution of thickener Add thickener AP-16 to a stainless steel basin, stir at a low speed of 300-500 rpm, add deionized water and stir for 15 minutes before use; (4) Blending: Add various raw materials in the following order Add water-based polyolefin emulsion BW5800 to the paint mixing tank and stir at a low speed of 300-500 rpm. Then add dimethylethanolamine, water-based inorganic lithium silicate modified pure acrylic ester multi-polymer self-crosslinking emulsion AS-86H2, main raw material ratio (1) dispersed conductive water slurry, main raw material ratio (2) dispersed pigment and filler water slurry, main raw material ratio (3) diluted thickener to adjust viscosity, change to a high speed of 800-1000 rpm and stir for 30 minutes. After all performances are qualified, use a filter to package.

[0010] The present invention uses water-based polyolefin emulsion BW5800 as a main resin, which has good adhesion to plastic substrates PP, PC, and ABS; by adding water-based inorganic lithium silicate modified pure acrylic ester multi-copolymer self-crosslinking emulsion AS-86H2, the hardness, water resistance, weather resistance and other medium resistance properties are further improved; by adding hydroxyl multi-arm carbon nanotube nanotube CNT202 and carboxyl multi-arm carbon nanotube nanotube CNT302, the paint film is conductive; by selecting Digo 750W dispersant, the hydroxyl multi-arm carbon nanotube nanotube CNT202 and carboxyl multi-arm carbon nanotube nanotube CNT302 are extremely well dispersed and have good storage stability; by adding silicon micropowder 1250 mesh, the hardness and moisture and heat resistance are improved; by adding an amine neutralizer, the pH value of the coating can be effectively controlled and the storage stability can be improved; by adding an alkali swelling thickener AP-16, the viscosity and storage stability of the coating can be effectively controlled in the case of adding a small amount. The conductive coating for plastic substrate prepared using the above raw materials is a water-based product that complies with environmental protection regulations. It has good adhesion to the plastic substrate and has excellent hardness, moisture and heat resistance, and resistance to various liquid media. It also has excellent conductive properties and can be applied by electrostatic spraying.

[0011] The present invention further discloses the application of a water-based conductive bottom-and-top integrated coating for plastic substrates in the electrostatic spraying construction of plastic parts. In particular, the application of water-based protective coatings for military plastic materials. Experimental results show that the coating film of the product of the present invention is flat and smooth, has a good appearance, and has excellent hardness, moisture and heat resistance, and resistance to various liquid media; and has excellent conductive properties, which can realize electrostatic spraying construction. In particular, in the field of military plastics, it can maintain the excellent performance of the coating under harsh conditions such as large temperature differences, high humidity, rain and snow in the field.

[0012] The present invention is described in more detail as follows: The method for preparing a water-based conductive primer-and-surface coating for a plastic substrate of the present invention comprises the following steps: (1) Preparation of conductive slurry Add deionized water to a stainless steel basin, stir at a low speed of 300-500 rpm, then add the wetting dispersant Digo 750W and stir for 10 minutes, add hydroxyl multi-arm carbon nanotubes CNT202 and carboxyl multi-arm carbon nanotubes CNT302, then switch to high speed 800-1000 rpm and stir for 30 minutes, use a sand mill to grind and disperse until the color paste fineness is less than 20μm, then filter it out for use; (This step is based on multiple comparisons in the screening of dispersants, and Digo 750W is selected for its excellent performance in wetting dispersion and reducing viscosity and grinding efficiency. The multi-arm carbon nanotubes are dispersed and ground separately to make the conductive effect more outstanding, and the grinding temperature is strictly controlled to be below 50℃) (2) Preparation of pigment and filler slurry Add deionized water to a stainless steel basin, stir at a low speed of 300-500 rpm, add the wetting and dispersing agent Digo 750W and stir for 10 minutes, then switch to a high speed of 800-1000 rpm, add U carbon black, add 1250 mesh silica powder, stir for 30 minutes, use a sand mill to grind and disperse until the color paste fineness is less than 20μm, then filter it out for use; (3) Dilution of thickener Add thickener AP-16 to a stainless steel basin, stir at a low speed of 300-500 rpm, add deionized water and stir for 15 minutes before use; (this step prevents excessive addition of thickener stock solution) (4) Blending: Add various raw materials in the following order Add water-based polyolefin emulsion BW5800 to the paint mixing tank and stir at a low speed of 300-500 rpm, then add dimethylethanolamine, water-based inorganic lithium silicate modified pure acrylic ester multi-polymer self-crosslinking emulsion AS-86H2, main raw material ratio (1) dispersed conductive water slurry, main raw material ratio (2) dispersed pigment and filler water slurry, main raw material ratio (3) diluted thickener to adjust viscosity, switch to high speed 800-1000 rpm and stir for 30 minutes. After all performances are qualified, use a filter to package. (In this step, you only need to pay attention to the need to neutralize the water-based polyolefin emulsion BW5800 and adjust the pH value to 8-9, and strictly control the mixing temperature below 50°C) Main raw material ratio (1) Preparation of conductive slurry Deionized water 50 Wetting and dispersing agent TEGO 750W 40 Hydroxyl multi-arm carbon nanotubes CNT202 5 Carboxyl multi-arm carbon nanotubes CNT302 5 (2) Preparation of pigment and filler slurry Deionized water 50 Wetting and dispersing agent TEGO 750W 10 U Carbon Black 10 Silicon powder 1250 mesh 30 (3) Dilution of thickener Thickener AP-16 50 Deionized water 50 (4) Harmony Water-based polyolefin emulsion BW5800 40-50 Dimethylethanolamine 0.1-0.2 Deionized water 10-15 Waterborne inorganic lithium silicate modified pure acrylate Multi-polymer self-crosslinking emulsion AS-86H2 5-10 Main raw material ratio (1) Dispersed conductive water slurry 4-8 Main raw material ratio (2) Dispersed pigment and filler water slurry 15-20 Deionized water 5-10 Main raw material ratio (3) diluted thickener AP-16 0.2-0.5 The invention aims at the large-scale production of plastic parts after the current coating is replaced with an aqueous system, and can also be electrostatically sprayed, and the paint film has excellent conductivity; the selected aqueous polyolefin emulsion BW5800 has excellent adhesion to plastic substrates PP, PC, and ABS; the selected aqueous inorganic lithium silicate modified pure acrylic ester multi-copolymer self-crosslinking emulsion AS-86H2 has ultra-high hardness, water resistance, weather resistance and other medium resistance; the selected hydroxyl multi-arm carbon nanotube nanotube CNT202 and carboxyl multi-arm carbon nanotube nanotube CNT302 realize the conductivity of the paint film, and because of their special structure and small addition amount, any color of paint can be realized; part of silicon micropowder filler is also added in the formula, and its silicon dioxide structure improves the hardness and moisture and heat resistance; the purpose of adding an amine neutralizer is to adjust the pH value of the system to be controlled at 8-9; the thickener AP-16 used is an alkali swelling type, and the viscosity of the system can be adjusted to a qualified level when the addition amount is very small.

[0013] Compared with the prior art, the water-based conductive primer-top integrated coating for plastic substrates disclosed in the present invention and its application have the following positive effects: The paint film is made of water-based polyolefin emulsion and water-based inorganic lithium silicate modified pure acrylic ester multi-polymer self-cross-linking emulsion, which makes the adhesion between the paint film and the substrate stronger, improves the hardness, water resistance, weather resistance, moisture and heat resistance and other media resistance, so that the coating remains stable in complex and harsh environments.

[0014] Hydroxyl multi-arm carbon nanotubes and carboxyl multi-arm carbon nanotubes are used in combination as conductive media in water-based paints. Due to their special structure, a relatively low addition amount can make the paint film excellently conductive. DETAILED DESCRIPTION

[0015] The present invention is described below by specific embodiments. Unless otherwise specified, the technical means used in the present invention are methods known to those skilled in the art. In addition, the embodiments should be understood as illustrative rather than limiting the scope of the present invention, and the essence and scope of the present invention are limited only by the claims. For those skilled in the art, various changes or modifications to the material composition and dosage in these embodiments, without departing from the essence and scope of the present invention, also belong to the protection scope of the present invention.

[0016] The raw materials and reagents used in the present invention are all commercially available, among which the water-based polyolefin emulsion BW5800 was purchased from Mitsubishi Chemical Corporation, the water-based inorganic lithium silicate modified pure acrylic ester multi-polymer self-crosslinking emulsion AS-86H2 was purchased from Jingzhou Aishi Environmental Protection New Materials, the hydroxyl multi-arm carbon nanotube conductive material CNT202 and the carboxyl multi-arm carbon nanotube conductive material CNT302 were purchased from Beijing Dekedaojin Technology Co., Ltd., the wetting and dispersing agent Tego750W was purchased from Digao Company, U carbon black was purchased from Orion Company, silicon micropowder 1250 mesh was purchased from Chuzhou Ge Rui Company, the thickener AP-16 was purchased from Mingling Company, and the amine neutralizer dimethylethanolamine was purchased from Yangzi Petrochemical. Example

[0017] A water-based conductive primer-top coating for plastic substrates Main raw material ratio: (1) Preparation of conductive slurry Deionized water 50 Wetting and dispersing agent TEGO 750W 40 Hydroxyl multi-arm carbon nanotubes CNT202 5 Carboxyl multi-arm carbon nanotubes CNT302 5 (2) Preparation of pigment and filler slurry Deionized water 50 Wetting and dispersing agent TEGO 750W 10 U Carbon Black 10 Silicon powder 1250 mesh 30 (3) Dilution of thickener Thickener AP-16 50 Deionized water 50 (4) Harmony Water-based polyolefin emulsion BW5800 50 Dimethylethanolamine 0.2 Deionized water 10 Waterborne inorganic lithium silicate modified pure acrylate Multi-polymer self-crosslinking emulsion AS-86H2 8 Main raw material ratio (1) Dispersed conductive water slurry 6 Main raw material ratio (2) Dispersed pigment and filler slurry 20 Deionized water 5 Main raw material ratio (3) diluted thickener AP-16 0.3 Example

[0018] A method for preparing water-based conductive primer-top coating for plastic substrate (1) Preparation of conductive slurry Add deionized water to a stainless steel basin, stir at a low speed of 300-500 rpm, then add a wetting dispersant, Digo 750W, and stir for 10 minutes. Add hydroxyl multi-arm carbon nanotubes CNT202 and carboxyl multi-arm carbon nanotubes CNT302, and then switch to a high speed of 800-1000 rpm for stirring for 30 minutes. Use a sand mill to grind and disperse the color paste until the fineness is 20 μm, then filter it out for use. (2) Preparation of pigment and filler slurry Add deionized water to a stainless steel basin, stir at a low speed of 300-500 rpm, add the wetting and dispersing agent Digo 750W and stir for 10 minutes, then switch to a high speed of 800-1000 rpm, add U carbon black, add 1250 mesh silica powder, stir for 30 minutes, use a sand mill to grind and disperse until the color paste fineness is 20 μm, then filter out for use; (3) Dilution of thickener Add thickener AP-16 to a stainless steel basin, stir at a low speed of 300-500 rpm, add deionized water and stir for 15 minutes before use; (4) Blending: Add various raw materials in the following order Add water-based polyolefin emulsion BW5800 to the paint mixing tank and stir at a low speed of 300-500 rpm, add dimethylethanolamine to adjust the pH to 8.5, and then add water-based inorganic lithium silicate modified pure acrylic ester multi-polymer self-crosslinking emulsion AS-86H2, the main raw material ratio (1) dispersed conductive water slurry, the main raw material ratio (2) dispersed pigment and filler water slurry, the main raw material ratio (3) diluted thickener to adjust the viscosity to 80ku, change to a high speed of 800-1000 rpm and stir for 30 minutes. After all the spray test performances are qualified, use a filter to package.

[0019]

[0020]

[0021] Example 3

[0022] Example 4 Comparison of resistivity of conductive carbon black with the same spray film thickness

[0023] Compared with conductive carbon black, the added amount is small, the cost is low, and the resistivity of conductive carbon black does not decrease significantly after it drops to a certain value.

[0024] Example 5 Comparison of resistivity with conductive mica powder at different film thicknesses

[0025] Compared with conductive mica powder, even when the spray film thickness is very thin, the resistivity is still very low and the conductivity is excellent. Conductive mica powder needs to ensure a certain film thickness to form conductivity.

[0026] Conclusion: The present invention is a water-based conductive bottom-and-top coating for plastic substrates. The coating film has excellent adhesion to plastics; better drying rate, hardness, weather resistance, resistance to various liquid media, and extremely stable coating in complex environments; the present invention realizes the complete water-based conductive bottom-and-top coating for plastic substrates, the product does not contain any organic solvents, and for the first time uses multi-arm carbon nanotube materials to achieve conductivity of the coating film, and the coating film has a resistance value of 10 at a thickness of less than 10μm. 4 Below Ω, the protective coating of military plastic materials has been made water-based.

Claims

1. A water-based conductive primer-and-surface coating for a plastic substrate, characterized in that The coating is composed of the following raw materials in parts by weight: Main raw material ratio (1) Preparation of conductive slurry Deionized water 50 Wetting and dispersing agent TEGO 750W 40 Hydroxyl multi-arm carbon nanotubes CNT202 5 Carboxyl multi-arm carbon nanotubes CNT302 5 (2) Preparation of pigment and filler slurry Deionized water 50 Wetting and dispersing agent TEGO 750W 10 U Carbon Black 10 Silica powder 1250 mesh 30 (3) Dilution of thickener Thickener AP-16 50 Deionized water 50 (4) Harmony Water-based polyolefin emulsion BW5800 40-50 Dimethylethanolamine 0.1-0.2 Deionized water 10-15 Waterborne inorganic lithium silicate modified pure acrylate Multi-polymer self-crosslinking emulsion AS-86H2 5-10 Main raw material ratio (1) Dispersed conductive water slurry 4-8 Main raw material ratio (2) Dispersed pigment and filler water slurry 15-20 Deionized water 5-10 Main raw material ratio (3) diluted thickener AP-16 0.2-0.

5.

2. The method for preparing a water-based conductive primer-and-surface coating for a plastic substrate according to claim 1, characterized in that Proceed as follows: (1) Preparation of conductive slurry Add deionized water to a stainless steel basin, stir at a low speed of 300-500 rpm, then add a wetting and dispersing agent Digo 750W and stir for 10 minutes, add hydroxyl multi-arm carbon nanotube nanotubes CNT202 and carboxyl multi-arm carbon nanotube nanotubes CNT302, then switch to a high speed of 800-1000 rpm and stir for 30 minutes, use a sand mill to grind and disperse until the color paste fineness is less than 20 μm, then filter out for use; (2) Preparation of pigment and filler slurry Add deionized water to a stainless steel basin, stir at a low speed of 300-500 rpm, add the wetting and dispersing agent Digo 750W and stir for 10 minutes, then switch to a high speed of 800-1000 rpm, add U carbon black, add 1250 mesh silica powder, stir for 30 minutes, use a sand mill to grind and disperse until the color paste fineness is less than 20μm, then filter it out for use; (3) Dilution of thickener Add thickener AP-16 to a stainless steel basin, stir at a low speed of 300-500 rpm, add deionized water and stir for 15 minutes before use; (4) Blending: Add various raw materials in the following order Add water-based polyolefin emulsion BW5800 to the paint mixing tank and stir at a low speed of 300-500 rpm. Then add dimethylethanolamine, water-based inorganic lithium silicate modified pure acrylic ester multi-polymer self-crosslinking emulsion AS-86H2, main raw material ratio (1) dispersed conductive water slurry, main raw material ratio (2) dispersed pigment and filler water slurry, main raw material ratio (3) diluted thickener to adjust viscosity, change to a high speed of 800-1000 rpm and stir for 30 minutes. After all performances are qualified, use a filter to package.

3. Use of the water-based conductive primer-top coating as claimed in claim 1 for coating plastic substrates on plastic parts.

4. Application of the water-based conductive primer-top coating for plastic substrates as described in claim 1 in water-based protective coatings for military plastic materials.

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