Water-based coating for speaker and preparation method thereof

Abstract

The present invention relates to the field of coating technology, and discloses a water-based coating for a speaker and a preparation method. The water-based coating for a speaker of the present invention includes 70-90 parts by weight of an acrylate monomer, 10-30 parts by weight of a styrene-based functional monomer, 0.5-0.7 parts by weight of an initiator, etc.; the styrene-based functional monomer contains multiple hydrophilic carboxyl groups, which imparts excellent hydrophilicity to the acrylic resin, and the water-based coating is not stratified and has good storage stability. The styrene-based functional monomer contains a carbamate group and a phthalic acid structure, so that the acrylic resin coating forms a very strong coordination interaction with the tinplate surface, and simultaneously contains multiple carboxyl groups, which form hydrogen bonds and other interactions with the hydroxyl groups on the wood surface, thereby improving the bonding strength and adhesion of the coating to the metal substrate and the wood surface, and can be applied to aspects such as speakers made of wood or metal materials.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, in particular to a water-based coating for a speaker and a preparation method thereof. Background Art

[0002] Speakers are a common household appliance. The shell material of high-end speakers is mainly solid wood or metal, which has good sound transmission performance and sound absorption effect, and is high strength and texture. It is usually necessary to apply a layer of paint on the surface of the solid wood or metal shell to play an anti-corrosion, waterproof, weather-resistant and other properties to protect the solid wood or metal shell of the speaker. Among them, acrylic resin paint has good color, gloss, film-forming properties and chemical resistance, and is widely used.

[0003] Water-based acrylic resin coatings use water as a solvent and are environmentally friendly. However, the preparation process typically requires the addition of water-based monomers such as acrylic acid and hydroxyethyl acrylate. However, traditional water-based acrylic resin coatings suffer from low adhesion to substrates such as solid wood and metal, and poor heat resistance of the paint film. Chinese patent CN117534797B discloses a fluorosilicone-modified acrylic resin, a smear-resistant coating, and a preparation method thereof. Using styrene, aliphatic polyurethane acrylate, a carboxyl-containing acrylic monomer, and a fluorosilicone-functional monomer as raw materials, the resulting acrylic resin coating exhibits advantages such as excellent smear resistance, high temperature resistance, wear resistance, and toughness. However, the patent does not address the low adhesion of acrylic resin coatings to wood and metal substrates. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a water-based paint for speakers and a preparation method, which solves the problems of poor adhesion, heat resistance and weather resistance of acrylic resin paint.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a water-based paint for speakers and a preparation method thereof, comprising the following raw materials: 70-90 parts by weight of acrylate monomer, 10-30 parts by weight of styrene-based functional monomer, 0.3-0.5 parts by weight of sodium bicarbonate, 2.6-3.4 parts by weight of emulsifier, 0.5-0.7 parts by weight of initiator, 0.3-0.5 parts by weight of defoamer, 0.2-0.3 parts by weight of leveling agent, and 18-25 parts by weight of color paste; the preparation method of the water-based paint for speakers is: adding Add acrylate monomer, styrene functional monomer, sodium bicarbonate and emulsifier, stir and prepare monomer solution; take 20-30% volume of monomer solution, heat to 65-80°C in nitrogen atmosphere, add dropwise an aqueous solution containing initiator, react for 40-60 minutes, then add the remaining 70-80% volume of monomer solution, add more aqueous solution containing initiator, react for 3-4 hours, cool, add dropwise a neutralizer to adjust the pH to 6.5-7.5, add defoamer, leveling agent and color paste, stir and disperse, and obtain water-based coating for speaker.

[0006] Furthermore, the acrylate monomer is any one or more of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate.

[0007] Furthermore, the emulsifier is any one or more of sodium lauryl sulfate, sodium lauryl sulfonate, sodium dodecylbenzenesulfonate, and OP-10.

[0008] Furthermore, the initiator is potassium persulfate or ammonium persulfate.

[0009] Furthermore, the neutralizing agent is triethylamine or an ammonia solution with a mass fraction of 10-30%.

[0010] Furthermore, the preparation method of the styrene-based functional monomer is as follows: 100 parts by weight of 3-isopropenyl-a,a'-dimethylbenzyl-isocyanate, 92-128 parts by weight of 4-hydroxyphthalic acid, and 0.4-0.7 parts by weight of dibutyltin dilaurate are added to N,N-dimethylformamide, stirred at 60-80°C for 3-5 hours, added with saturated sodium chloride solution, extracted with dichloromethane, allowed to stand for separation, and after separation, the organic layer is dried over anhydrous sodium sulfate to remove water, filtered, and the filtrate is rotary evaporated, the product is washed with petroleum ether, and then recrystallized in dichloromethane to obtain a styrene-based functional monomer.

[0011] The present invention adopts the above-mentioned technical solution, which has the beneficial technical effect of copolymerizing an acrylate monomer such as butyl acrylate with a styrene-functional monomer to produce a water-based coating. The styrene-functional monomer contains multiple hydrophilic carboxyl groups, which impart excellent hydrophilicity to the acrylic resin, resulting in a water-based coating that does not delaminate and has excellent storage stability.

[0012] The styrene-based functional monomer of the present invention contains a carbamate group and a phthalic acid structure, which enables the acrylic resin coating to form a strong coordination and other interaction forces with the tinplate surface. At the same time, it contains multiple carboxyl groups, which form hydrogen bonds and other interaction forces with the hydroxyl groups on the wood surface, thereby improving the bonding strength and adhesion between the coating and the metal substrate and the wood surface. The coating can be applied to wooden or metal speakers and the like.

[0013] The invention polymerizes styrene-based functional monomers and acrylate monomers and then introduces heat-resistant polystyrene block molecular chains into acrylic resin molecular chains, which is beneficial to increasing the initial thermal decomposition temperature of the coating and improving the heat and weather resistance of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the styrene-based functional monomer. DETAILED DESCRIPTION

[0015] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as limiting the present invention.

[0016] Example 1

[0017] (1) Add 50g of 3-isopropenyl-a,a'-dimethylbenzyl-isocyanate, 52g of 4-hydroxyphthalic acid, and 0.3g of dibutyltin dilaurate to 700mL of N,N-dimethylformamide, stir and react at 65℃ for 5h, add saturated sodium chloride solution, extract with dichloromethane, stand and separate, dry the organic layer with anhydrous sodium sulfate to remove water, filter, rotary evaporate the filtrate, wash the product with petroleum ether, and then recrystallize from dichloromethane to obtain a styrene-based functional monomer. The preparation reaction formula is as follows:

[0018] .

[0019] Figure 1 The chemical shift values ​​of the styrene functional monomer in the H NMR spectrum are 1 H NMR (CDCl 3 ) δ: 11.07 (2H), 8.39 (1H), 7.99 (1H), 7.53 (3H), 7.32 (2H), 6.49 (1H), 5.34 (1H), 4.98 (1H), 2.57 (3H), 1.63 (6H).

[0020] (2) Add 230g of methyl methacrylate, 580g of butyl acrylate, 90g of 2-ethylhexyl methacrylate, 100g of styrene-based functional monomer, 3.7g of sodium bicarbonate, 9.5g of sodium lauryl sulfate, and 19g of OP-10 to 1.8L of water, and stir to prepare a monomer solution; take 25% volume of the monomer solution, heat it to 70℃ in a nitrogen atmosphere, add 50mL of an aqueous solution containing 1.7g of ammonium persulfate, and react for 60min, then add the remaining 75% volume of the monomer solution, add 150mL of an aqueous solution containing 3.6g of ammonium persulfate, and react for 3h, cool it, add 25% by mass ammonia solution to adjust the pH to 7, add 4.2g of defoamer (model BYK-019), 2.3g of leveling agent (model Aidico UH-420), and 210g of iron red 8811 water-based color paste, stir and disperse, and obtain a water-based coating for speakers.

[0021] Example 2

[0022] (1) Add 50 g of 3-isopropenyl-a,a'-dimethylbenzyl isocyanate, 64 g of 4-hydroxyphthalic acid, and 0.2 g of dibutyltin dilaurate to 700 mL of N,N-dimethylformamide, stir and react at 60 °C for 5 h, add saturated sodium chloride solution, extract with dichloromethane, let stand and separate, dry the organic layer with anhydrous sodium sulfate, filter, and rotary evaporate the filtrate. Wash the product with petroleum ether and then recrystallize it from dichloromethane to obtain a styrene-based functional monomer.

[0023] (2) Add 220g methyl methacrylate, 545g butyl methacrylate, 85g 2-ethylhexyl acrylate, 250g styrene-based functional monomer, 3-5g sodium bicarbonate, 9g sodium dodecylbenzenesulfonate, and 17g OP-10 to 1.5-2L water, and stir to prepare a monomer solution; take 30% volume of the monomer solution, heat it to 75℃ in a nitrogen atmosphere, add 70mL of an aqueous solution containing 2g of ammonium persulfate, and react for 40min, then add the remaining 70% volume of the monomer solution, add 100-200mL of an aqueous solution containing 5g of ammonium persulfate, and react for 4h. After cooling, add triethylamine to adjust the pH to 7, add 5g of defoamer (model BYK-019), 2.3g of leveling agent (model Aidico UH-420), and 250g of iron red 8811 water-based color paste, stir and disperse, and obtain a water-based coating for speakers.

[0024] Example 3

[0025] (1) Add 50 g of 3-isopropenyl-a,a'-dimethylbenzyl isocyanate, 46 g of 4-hydroxyphthalic acid, and 0.35 g of dibutyltin dilaurate to 600 mL of N,N-dimethylformamide, stir and react at 80 °C for 3 h, add saturated sodium chloride solution, extract with dichloromethane, let stand and separate, dry the organic layer with anhydrous sodium sulfate, filter, and rotary evaporate the filtrate. Wash the product with petroleum ether and then recrystallize it from dichloromethane to obtain a styrene-based functional monomer.

[0026] (2) Add 210g methyl acrylate, 520g butyl acrylate, 65g 2-ethylhexyl acrylate, 200g styrene-based functional monomer, 3-5g sodium bicarbonate, 10g sodium dodecylsulfonate, and 19g OP-10 to 1.5-2L water, and stir to prepare a monomer solution; take 25% volume of the monomer solution, heat it to 80℃ in a nitrogen atmosphere, add 50-70mL of an aqueous solution containing 2g of ammonium persulfate, and react for 40min, then add the remaining 75% volume of the monomer solution, add 100-200mL of an aqueous solution containing 4.6g of ammonium persulfate, and react for 3h, cool it, add 10% by mass ammonia solution to adjust the pH to 7.5, add 3g defoamer (model BYK-019), 3g leveling agent (model Aidico UH-420), and 180g iron red 8811 water-based color paste, stir and disperse, and obtain a water-based coating for speakers.

[0027] Example 4

[0028] (1) Prepare a styrene-based functional monomer according to the method of Example 1.

[0029] (2) Add 170g of methyl acrylate, 510g of butyl methacrylate, 70g of 2-ethylhexyl methacrylate, 250g of styrene-based functional monomer, 3-5g of sodium bicarbonate, 11.5g of sodium lauryl sulfate, and 22.5g of OP-10 to 1.5-2L of water, and stir to prepare a monomer solution; take 20% volume of the monomer solution, heat it to 75℃ in a nitrogen atmosphere, add 70mL of an aqueous solution containing 1.7g of potassium persulfate, and react for 40min, then add the remaining 80% volume of the monomer solution, add 100-200mL of an aqueous solution containing 4.8g of potassium persulfate, and react for 3h, cool it, add 30% by mass ammonia solution to adjust the pH to 6.5, add 5g of defoamer (model BYK-019), 2g of leveling agent (model Aidico UH-420), and 215g of iron red 8811 water-based color paste, stir and disperse, and obtain a water-based coating for speakers.

[0030] Example 5

[0031] (1) Prepare styrene-based functional monomers according to the method of Example 1.

[0032] (2) Add 155g of methyl methacrylate, 485g of butyl acrylate, 60g of 2-ethylhexyl acrylate, 300g of styrene-based functional monomer, 3-5g of sodium bicarbonate, 10g of sodium lauryl sulfate, and 20g of OP-10 to 1.5-2L of water, and stir to prepare a monomer solution; take 25% volume of the monomer solution, heat it to 65°C in a nitrogen atmosphere, add 70mL of an aqueous solution containing 1.4g of ammonium persulfate, react for 60min, then add the remaining 75% volume of the monomer solution, add 150mL of an aqueous solution containing 3.6g of ammonium persulfate, react for 4h, cool, add triethylamine to adjust the pH to 7, add 4.6g of defoamer (model BYK-019), 2.5g of leveling agent (model Aidico UH-420), and 235g of iron red 8811 water-based color paste, stir and disperse, and obtain a water-based coating for speakers.

[0033] Comparative Example 1

[0034] (1) Add 230g of methyl methacrylate, 580g of butyl acrylate, 90g of 2-ethylhexyl methacrylate, 100g of acrylic acid, 3.7g of sodium bicarbonate, 9.5g of sodium lauryl sulfate, and 19g of OP-10 to 1.8L of water, and stir to prepare a monomer solution; take 25% volume of the monomer solution, heat it to 70℃ in a nitrogen atmosphere, add 50mL of an aqueous solution containing 1.7g of ammonium persulfate, and react for 60min, then add the remaining 75% volume of the monomer solution, add 150mL of an aqueous solution containing 3.6g of ammonium persulfate, and react for 3h, cool it, add 25% by mass ammonia solution to adjust the pH to 7, add 4.2g of defoamer (model BYK-019), 2.3g of leveling agent (model Aidico UH-420), and 210g of iron red 8811 water-based color paste, stir and disperse, and obtain a water-based coating for speakers.

[0035] Comparative Example 2

[0036] (1) Add 230g of methyl methacrylate, 580g of butyl acrylate, 90g of 2-ethylhexyl methacrylate, 100g of styrene, 3.7g of sodium bicarbonate, 9.5g of sodium lauryl sulfate, and 19g of OP-10 to 1.8L of water, and stir to prepare a monomer solution; take 25% volume of the monomer solution, heat it to 70℃ in a nitrogen atmosphere, add 50mL of an aqueous solution containing 1.7g of ammonium persulfate, react for 60min, then add the remaining 75% volume of the monomer solution, add 150mL of an aqueous solution containing 3.6g of ammonium persulfate, react for 3h, cool, add 4.2g of defoamer (model BYK-019), 2.3g of leveling agent (model Aidico UH-420), and 210g of iron red 8811 water-based color paste, stir and disperse, and obtain a coating for speakers.

[0037] Comparative Example 3

[0038] (1) Add 230g of methyl methacrylate, 580g of butyl acrylate, 90g of 2-ethylhexyl methacrylate, 100g of 4-vinylbenzoic acid, 3.7g of sodium bicarbonate, 9.5g of sodium lauryl sulfate, and 19g of OP-10 to 1.8L of water, and stir to prepare a monomer solution; take 25% volume of the monomer solution, heat it to 70℃ in a nitrogen atmosphere, add 50mL of an aqueous solution containing 1.7g of ammonium persulfate, and react for 60min, then add the remaining 75% volume of the monomer solution, add 150mL of an aqueous solution containing 3.6g of ammonium persulfate, and react for 3h, cool it, add 25% by mass ammonia solution to adjust the pH to 7, add 4.2g of defoamer (model BYK-019), 2.3g of leveling agent (model Aidico UH-420), and 210g of iron red 8811 water-based color paste, stir and disperse, and obtain a water-based coating for speakers.

[0039] Comparative Example 4

[0040] (1) Add 50 g of 3-isopropenyl-a,a'-dimethylbenzyl-isocyanate, 26.9 g of phenol, and 0.3 g of dibutyltin dilaurate to 600 mL of N,N-dimethylformamide, stir and react at 65 °C for 5 h, add saturated sodium chloride solution, extract with dichloromethane, let stand and separate, dry the organic layer with anhydrous sodium sulfate, filter, and rotary evaporate the filtrate. Wash the product with petroleum ether and then recrystallize it from dichloromethane to obtain a styrene functional monomer with the structural formula: .

[0041] (2) Add 230g of methyl methacrylate, 580g of butyl acrylate, 90g of 2-ethylhexyl methacrylate, 100g of styrene-based functional monomer, 3.7g of sodium bicarbonate, 9.5g of sodium lauryl sulfate, and 19g of OP-10 to 1.8L of water, and stir to prepare a monomer solution; take 25% volume of the monomer solution, heat it to 70℃ in a nitrogen atmosphere, add 50mL of an aqueous solution containing 1.7g of ammonium persulfate, react for 60min, then add the remaining 75% volume of the monomer solution, add 150mL of an aqueous solution containing 3.6g of ammonium persulfate, react for 3h, cool, add 4.2g of defoamer (model BYK-019), 2.3g of leveling agent (model Aidico UH-420), and 210g of iron red 8811 water-based color paste, stir and disperse, and obtain a coating for speakers.

[0042] Place the coating at room temperature for 3-6 months and observe the storage stability of the coating.

[0043] The paint was sprayed on the surface of tinplate and poplar veneer respectively, baked at 90℃ for 6 hours to form a paint film, and the adhesion grade was tested according to the method specified in GB T 9286-2021.

[0044] Pencil hardness is tested according to the method specified in GB / T 6739-2022.

[0045] The paint film was subjected to thermal performance testing in a thermogravimetric analyzer with a heating rate of 10°C / min and a test temperature of 30-700°C.

[0046] Table 1 Performance test of coatings

[0047]

[0048] As shown in the above table, after the water-based paint of embodiment 1-5 has been stored for 3-6 months, the coating is not stratified, mainly because the styrene-functional monomer added contains multiple hydrophilic carboxyl groups, has given the excellent wetting property of acrylic resin, and the water-based paint is not stratified, and has good storage stability.And the adhesion grade on tinplate and poplar veneer surface all reaches 1 to 0 level, mainly because the styrene-functional monomer contains carbamate group and phthalic acid structure, forms very strong interaction forces such as coordination with the tinplate surface, contains multiple carboxyl groups simultaneously, forms interaction forces such as hydrogen bond with the hydroxyl of timber surface, thereby improves bonding strength and the sticking power of coating and metal substrate and timber surface.And after the styrene-functional monomer and acrylate monomer polymerization, the thermostable polystyrene block molecular chain is incorporated in the acrylic resin molecular chain, is conducive to improving the thermostable of coating, shows higher initial thermal decomposition temperature.

[0049] Comparative Example 1 uses conventional acrylic acid as a water-based monomer, which does not contain a carbamate group and a phthalic acid structure. It has low interaction force and bonding strength with tinplate and wood surfaces, resulting in poor adhesion, and has a low initial thermal decomposition temperature and poor heat resistance.

[0050] In Comparative Example 2, styrene was added, and the acrylic resin did not contain a hydrophilic carboxyl group, resulting in poor hydrophilicity of the coating. The coating was easily delaminated after storage, and did not contain a carbamate group and a phthalic acid structure. The interaction force and bonding strength between the coating and the tinplate and wood surfaces were low, and the adhesion was poor.

[0051] Comparative Example 3 uses 4-vinylbenzoic acid as the functional monomer. After long-term storage (6 months), the coating is easy to delaminate and has poor storage stability. It does not contain carbamate groups and phthalic acid structures. The interaction force and bonding strength between the coating and the tinplate and wood surfaces are low, and the adhesion is poor.

[0052] The styrene functional monomer of Comparative Example 4 does not contain a hydrophilic carboxyl group, resulting in poor hydrophilicity of the coating, easy stratification, poor storage stability, and no phthalic acid structure. The interaction force and bonding strength with tinplate and wood surfaces are low, and the adhesion is poor.

[0053] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A water-based paint for a speaker, characterized in that: The water-based paint for the speaker comprises the following raw materials: 70-90 parts by weight of acrylate monomer, 10-30 parts by weight of styrene-based functional monomer, 0.3-0.5 parts by weight of sodium bicarbonate, 2.6-3.4 parts by weight of emulsifier, 0.5-0.7 parts by weight of initiator, 0.3-0.5 parts by weight of defoamer, 0.2-0.3 parts by weight of leveling agent, and 18-25 parts by weight of color paste; The water-based paint for the speaker further includes a neutralizer; The preparation method of the styrene-based functional monomer comprises: adding 3-isopropenyl-α,α-dimethylbenzyl isocyanate, 4-hydroxyphthalic acid, and dibutyltin dilaurate to N,N-dimethylformamide, adding a saturated sodium chloride solution after the reaction, extracting with dichloromethane, standing to separate the layers, drying the organic layer with anhydrous sodium sulfate to remove water, filtering, rotary evaporating the filtrate, washing the product with petroleum ether, and then recrystallizing it in dichloromethane to obtain the styrene-based functional monomer; The preparation method of the water-based coating for the speaker comprises the following steps: adding an acrylate monomer, a styrene-based functional monomer, sodium bicarbonate, and an emulsifier to water, and stirring to prepare a monomer solution; taking 20-30% by volume of the monomer solution, heating it to 65-80° C. in a nitrogen atmosphere, dripping an aqueous solution containing an initiator, reacting for 40-60 minutes, then adding the remaining 70-80% by volume of the monomer solution, further adding an aqueous solution containing an initiator, reacting for 3-4 hours, cooling, dripping a neutralizer to adjust the pH to 6.5-7.5, adding a defoaming agent, a leveling agent, and a color paste, and stirring and dispersing to obtain the water-based coating for the speaker.

2. The water-based paint for a speaker according to claim 1, characterized in that: The acrylic acid ester monomer is any one or more of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate.

3. The water-based paint for a speaker according to claim 1, characterized in that: The emulsifier is any one or more of sodium lauryl sulfate, sodium lauryl sulfonate, sodium dodecylbenzenesulfonate, and OP-10.

4. The water-based paint for a speaker according to claim 1, characterized in that: The initiator is potassium persulfate or ammonium persulfate.

5. The water-based paint for a speaker according to claim 1, characterized in that: The neutralizing agent is triethylamine or an ammonia solution with a mass fraction of 10-30%.

6. The water-based paint for a speaker according to claim 1, characterized in that: The amount of the 3-isopropenyl-α,α-dimethylbenzyl isocyanate is 100 parts by weight, the amount of 4-hydroxyphthalic acid is 92-128 parts by weight, and the amount of dibutyltin dilaurate is 0.4-0.7 parts by weight.

7. The water-based paint for a speaker according to claim 1, characterized in that: In the preparation of the styrene-based functional monomer, the reaction is stirred at 60-80° C. for 3-5 hours.

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