A method of making and using a coating material for pretreatment of polycarbonate substrates for functional plating

Abstract

The application discloses a coating material for pretreatment of a polycarbonate substrate functional coating, which is composed of alcohol-soluble acrylic oligomer, siloxane monomer, adhesion promoter, solvent 1, catalyst, other additives, and the alcohol-soluble acrylic oligomer is composed of methyl methacrylate, hydroxypropyl acrylate, styrene, methyl glycidyl methacrylate, vinyl triethoxysilane, solvent 2 and initiator; the coating can effectively enhance the adhesion and weather resistance between the substrate and the coating layer, obviously improve the coating effect, and the coating prepared has good adhesion, weather resistance, heat resistance, boiling water resistance between the coating and the substrate, excellent gloss, leveling property, no shrinkage hole and no particle on the surface, excellent adhesion, gloss and mirror effect between the coating layer and the coating after coating, and good use effect. The coating can effectively enhance the transition between the substrate and the coating layer, enhance the adhesion and weather resistance, and obviously improve the coating effect.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical coating materials and application technology, specifically relating to the preparation and application method of a coating material for pretreatment of functional coating on polycarbonate substrate. Background Technology

[0002] Polycarbonate (PC) is an engineering plastic with excellent comprehensive performance due to its outstanding impact toughness, transparency, dimensional stability, good mechanical strength, electrical insulation, wide operating temperature range, good creep resistance, weather resistance, low water absorption, non-toxicity, and self-extinguishing properties, making it an important material for transparent parts. To meet the increasing functional requirements of transparent PC parts, a coating is generally applied to its surface. These functional coatings mainly include gold films, indium tin oxide (ITO), antimony tin oxide (ITO), and laminates of two or more types. However, due to the difference in thermal expansion coefficients between the PC substrate and the film material, thermal stress can occur in the film. Excessive stress can cause the film to crack or even peel off. Furthermore, PC is injection molded, and mold release agents may be used during the injection molding stage to improve demolding efficiency and yield. This can result in mold release agent contamination on the surface, affecting subsequent processes and the overall surface finish after coating, causing phenomena such as oil spots, oil patches, pinholes, and crater-like defects. Therefore, surface treatment is required before PC coating. For example, in patent CN200510035829.6, the steps of sandblasting and cleaning are used to improve the adhesion between the coating and the PC substrate. Another example is the use of an oil stain removal agent and a solvent-free UV primer, which covers the oil stains by forming a film, has good leveling, and does not affect the gloss of the coating.

[0003] Existing PC coating pretreatment processes mainly include physical and chemical methods, both of which have certain shortcomings or defects. For example, physical treatment uses sandblasting and cleaning processes, which require specialized sandblasting equipment, increasing coating costs. Similarly, chemical treatment methods, such as oil stain removal agents and UV primers, are complex processes and require specialized UV curing equipment, which also increases coating costs. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing and using a coating material for pretreatment of functional coatings on polycarbonate substrates; a silicone-modified alcohol-soluble acrylic resin coating for coating polycarbonate substrates, which requires no special treatment of the substrate. The coating is directly applied to the surface of the PC substrate using a flow coating or spray coating process, and a PC coating base layer can be formed at room temperature (heat). This coating has good adhesion, weather resistance, heat resistance, and water resistance (the coating adhesion can still reach 5B after boiling in water for 8 hours). The coating also has excellent gloss and leveling properties, and the surface is free of pinholes and particles. After the coating is applied, the film layer and the coating layer have excellent adhesion, gloss, and mirror effect. The coating solvent system is environmentally friendly, the construction process is simple and easy to operate, and no additional treatment processes or equipment are required, effectively reducing the cost of coating materials and demonstrating good performance and economic value.

[0005] This invention provides a coating material for functional pretreatment of polycarbonate substrates, comprising the following components by weight percentage:

[0006]

[0007] The alcohol-soluble acrylic oligomer is self-made.

[0008] The alcohol-soluble acrylic oligomer comprises the following components by mass percentage:

[0009]

[0010] The solvent 2 is selected from at least one of ethanol, n-propanol, isopropanol, n-butanol, and isobutanol.

[0011] The initiator is selected from one or two of benzoyl peroxide (BPO), dilauroyl peroxide (LPO), tert-butyl peroxide-2-ethylhexanoate (TBPO), diisopropyl peroxide dicarbonate (IPP), and tert-butyl peroxypentanoate (BPP).

[0012] The preparation method of the alcohol-soluble acrylic acid oligomer:

[0013] Step 1: Add 30% MMA, 30% HPA, 20% ST, 10% GMA, 10% VTEO and 70% Solvent 2 to the reactor, stir and heat to about 75-80℃, and keep at this temperature for 0.5h.

[0014] Step 2: Add the remaining 70% MMA, 70% HPA, 80% ST, 90% GMA, 90% VTEO, and 30% solvent 2, along with the initiator, dropwise at a rate of 60 ml / min. After the addition is complete, keep the system at 75-80°C for 4 hours to allow it to react. Then, cool the system to obtain the alcohol-soluble acrylic oligomer.

[0015] The siloxane monomer is selected from at least one of methylphenyldiethoxysilane, phenyltriethoxysilane, methyltriethoxysilane, and dimethyldiethoxysilane.

[0016] The adhesion promoter is self-made.

[0017] Solvent 1 is a mixture of ethanol and at least one of n-propanol, isopropanol, n-butanol, and isobutanol in a mass ratio of 1:1 to 2:1. The purpose is to improve the solvent's dissolution effect and increase the evaporation gradient, which can effectively improve the surface condition of the coating. The solvent does not participate in the actual preparation process.

[0018] The catalyst is selected from at least one of phosphoric acid, sulfuric acid, hydrochloric acid, acetic acid, and formic acid.

[0019] The other adjuvants are selected from at least one of BYK-358, BYK-306, Deqian 411, Dow Corning 5211, and Henkel F60.

[0020] Method for preparing coating materials for pretreatment of functional coatings on polycarbonate substrates:

[0021] Alcohol-soluble acrylic oligomer, siloxane monomer, adhesion promoter, and solvent 1 are added to a reaction flask and stirred. The catalyst is added dropwise and the reaction is continued for 2-3 hours. Then the temperature is raised to reflux and kept at reflux for 1 hour. After cooling to room temperature, other additives are added to obtain a coating material for pretreatment of functional coating on polycarbonate substrate.

[0022] Method of using the coating material for pretreatment of functional coating on polycarbonate substrate:

[0023] The prepared coating material for pretreatment of functional coating on polycarbonate substrate is directly coated onto polycarbonate substrate using flow coating or spray coating process. After leveling and surface drying for about 20 minutes, it is directly placed in a constant temperature drying oven at 120℃ for 2-3 hours or dried at room temperature for at least 48 hours to obtain the coating material for pretreatment of functional coating on polycarbonate substrate, and then the coating can be carried out.

[0024] Beneficial effects

[0025] This invention provides a coating material for pretreatment of functional coatings on polycarbonate substrates. The preparation and use of this coating have the following advantages:

[0026] A self-made alcohol-soluble acrylic oligomer was prepared, and the alcohol-soluble acrylic oligomer was modified with a siloxane monomer. A self-made adhesion promoter was introduced. The operation was simple, and a one-component resin coating was prepared. It is convenient and safe to use, and the coating solvent system is environmentally friendly.

[0027] The coating application process is simple and easy to operate, requiring no additional processing techniques or equipment, effectively reducing the cost of coating materials and possessing good economic value.

[0028] The prepared coating exhibits excellent adhesion, weather resistance, heat resistance, and water resistance to the substrate. It also possesses excellent gloss and leveling properties, with no pinholes or particles on the surface. Furthermore, after recoating, the film layer and the coating itself maintain excellent adhesion, gloss, and a mirror-like finish, demonstrating good performance. This coating itself is not used as a primary functional coating or application material on the substrate surface; its ultimate purpose is to effectively improve the transition between the substrate and the coating layer, enhance adhesion and weather resistance, significantly improve the coating effect, reduce coating costs, and increase economic efficiency. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] Preparation of alcohol-soluble acrylic oligomers: Step 1: Add 45g MMA, 90g HPA, 4g ST, 2g GMA, 2g VTEO, and 210g isopropanol to a reactor, stir and heat to about 75℃, and maintain this temperature for 0.5h. Step 2: Add the remaining 105g MMA, 210g HPA, 16g ST, 18g GMA, 18g VTEO, 90g isopropanol, and 1.0g IPP dropwise at a rate of 60ml / min. After the addition is complete, maintain the system at 75℃ for 4h, then cool to obtain alcohol-soluble acrylic oligomer D1.

[0032] Example 2

[0033] Preparation of alcohol-soluble acrylic oligomers: Step 1: Add 33g MMA, 66g HPA, 6g ST, 4g GMA, 4g VTEO, and 180g isopropanol to a reactor, stir and heat to about 75℃, and maintain this temperature for 0.5h. Step 2: Dropwise add the remaining 66g MMA, 102g HPA, 14g ST, 14g GMA, 15g VTEO, 80g isopropanol, and 1.5g LPO, controlling the dropping rate at 60ml / min. After the addition is complete, maintain the system at 75℃ for 4h, then cool to obtain alcohol-soluble acrylic oligomer D2.

[0034] Example 3

[0035] Preparation of the undercoat for polycarbonate substrate coating: 44g D1, 30g methyltriethoxysilane, 5g adhesion promoter and 70g solvent 1 (ethanol:isopropanol = 1:1) were added to a reaction flask and stirred. 0.1g hydrochloric acid was added dropwise and the reaction was continued for 2.5h. Then the temperature was raised to reflux and kept at reflux for 1h. After cooling to room temperature, 0.1g BYK-306 was added to obtain coating material DY-1 for pretreatment of functional coating on polycarbonate substrate.

[0036] Example 4

[0037] Preparation of the undercoat for polycarbonate substrate coating: 60g D2, 40g phenyltriethoxysilane, 20g dimethyldiethoxysilane, 7g adhesion promoter and 100g solvent 1 (ethanol: n-butanol = 2:1) were added to a reaction flask and stirred. 0.15g hydrochloric acid was added dropwise and the reaction was continued for 2.5h. Then the temperature was raised to reflux and kept at reflux for 1h. After cooling to room temperature, 0.15g BYK-358 was added to obtain coating material DY-2 for pretreatment of functional coating on polycarbonate substrate.

[0038] Example 5

[0039] Application method of the undercoat coating for polycarbonate substrate: The prepared undercoat coatings D1 and D2 for polycarbonate substrate are directly coated onto the polycarbonate substrate using a flow coating process (no other treatment of the polycarbonate substrate is required). After leveling and surface drying for 20 minutes, the coating is placed directly in a constant temperature drying oven at 120℃ for 2 hours to cure. The coating for pretreatment of functional coating of polycarbonate substrate is obtained, and then vacuum coating is performed.

[0040] Technical effects of the present invention

[0041] The adhesion and adhesion after boiling were tested according to ASTM D3359 standard for the coatings prepared in the examples. After coating, the surface condition of the coating and the coated film were observed. The results are shown in the table below:

[0042]

[0043] As can be seen from the table above, the present invention has achieved good technical results.

[0044] This disclosure has been described with reference to the foregoing embodiments; however, these embodiments are merely examples for implementing this disclosure. It must be noted that the disclosed embodiments do not limit the scope of this disclosure. On the contrary, any changes and modifications made without departing from the spirit and scope of this disclosure are within the scope of patent protection of this disclosure.

Claims

1. A method of using a coating material for pretreatment of a polycarbonate substrate for functional plating, characterized by: The prepared polycarbonate substrate functional coating pretreatment primer is coated on the polycarbonate substrate by flow coating or spraying process, and then the substrate is placed in a constant temperature drying oven at 120℃ for 2-3h after leveling and drying for 20min, to obtain a polycarbonate substrate coating primer, and then the coating process can be carried out; The polycarbonate substrate functional coating pretreatment coating material comprises the following components in percentage by mass: Alcohol-soluble acrylic oligomer 10%~40% Siloxane monomer 5%~40% Adhesion promoter 2%~7% Solvent 1 40%~70% Catalyst 0.05%~0.1% Other additives 0.05%~0.1% The solvent 1 is a mixture of ethanol and at least one of n-propanol, isopropanol, n-butanol and isobutanol in a mass ratio of 1:1~2:

1. The alcohol-soluble acrylic oligomer comprises the following components in percentage by mass: Methyl methacrylate 10~20% Hydroxypropyl acrylate 20~40% Styrene 1~6% Methyl glycidyl methacrylate 1~6% Vinyl triethoxysilane 1~6% Solvent 2 25~65% Initiator 0.1~0.3%, The preparation method of the alcohol-soluble acrylic oligomer is as follows: 30% of methyl methacrylate, 30% of hydroxypropyl acrylate, 20% of styrene, 10% of methyl glycidyl methacrylate, 10% of vinyl triethoxysilane and 70% of solvent 2 are added into a reactor, stirred and heated to 75-80℃, and kept for 0.5h; the remaining 70% of methyl methacrylate, 70% of hydroxypropyl acrylate, 80% of styrene, 90% of methyl glycidyl methacrylate, 90% of vinyl triethoxysilane and 30% of solvent 2 and an initiator are added dropwise, the dropping speed is controlled at 60ml / min, after the dropping is completed, the system is kept in an environment of 75-80℃ for 4h, and then cooled to obtain the alcohol-soluble acrylic oligomer. The siloxane monomer is at least one of methylphenyldiethoxysilane and phenyltriethoxysilane.

2. The method of using a coating material for pretreatment of a polycarbonate substrate for functional plating according to claim 1, characterized in that: The solvent 2 is at least one of ethanol, n-propanol, isopropanol, n-butanol and isobutanol; and the initiator is one or two of dibenzoyl peroxide, dilauryl peroxide, tert-butyl peroxy-2-ethylhexanoate, diisopropyl peroxydicarbonate and tert-butyl peroxypivalate.

3. The method of using a coating material for pretreatment of polycarbonate substrates for functional plating according to claim 1, characterized in that: The catalyst is at least one of phosphoric acid, sulfuric acid, hydrochloric acid, acetic acid and formic acid.

4. The method of using a coating material for pretreatment of a polycarbonate substrate for functional plating according to claim 1, characterized in that: The other additives are one or more of BYK-358, BYK-306, Decon 411, Dow Corning 5211 and Hanse F60.

5. The method of using a coating material for pretreatment of polycarbonate substrates for functional plating according to claim 1, characterized in that: The polycarbonate substrate functional coating pretreatment coating material is prepared by the following method, including the following steps: alcohol-soluble acrylic oligomer, siloxane monomer, adhesion promoter, solvent 1 are added into a reaction bottle and stirred, the catalyst is added dropwise and continuously reacted for 2-3h, then heated to reflux, kept at reflux for 1h, cooled to room temperature and added with other additives, to obtain the polycarbonate substrate functional coating pretreatment coating material.

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