High-adhesion water-based vinylidene chloride copolymer emulsion for metal surface and preparation method thereof

A technology of vinylidene chloride and high adhesion, applied in the direction of coating, etc., can solve the problems of restricting the application of vinylidene chloride resin, poor adhesion of metal substrates, and decreased coating adhesion, so as to improve the barrier performance of resin, Improves resin adhesion and facilitates migration

Active Publication Date: 2020-09-25

TIANJIN CHENGJIAN UNIV

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AI-Extracted Technical Summary

Problems solved by technology

Water-based vinylidene chloride coatings can be prepared by dispersing vinylidene chloride copolymer emulsion with functional additives, pigments and fillers. This type of coating has good properties such as moisture resistance, abrasion resistance, oil resistance, chemical corrosion resistance and flame retardancy. The adhesion on the metal substrate is not good, and the paint film is easy to fall off in a large area, which seriously restricts the application of vinylidene chloride resin in the field of metal anti-corrosion coatings

[0003] Copolymerization of vinylidene chloride with acrylate and ot...

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Abstract

The invention discloses a high-adhesion water-based vinylidene chloride copolymer emulsion for a metal surface and a preparation method of the high-adhesion water-based vinylidene chloride copolymer emulsion. The preparation method comprises the following steps of: fully stirring vinylidene chloride, acrylate, an emulsifier and water to form a pre-emulsified liquid, adding part of the pre-emulsified liquid and a functional monomer into a reactor, initiating a polymerization reaction by adopting a redox system, reacting at constant temperature for a period of time, adding the residual pre-emulsified liquid into the reactor at one time, and continuously reacting to obtain the emulsion resin. The emulsion disclosed by the invention is good in storage stability and uniform in particle size, and the resin is extremely strong in adhesive force on a metal surface, has relatively good barrier property and corrosion resistance, and can be used as matrix resin for a metal substrate anticorrosivecoating.

Application Domain

Coatings

Technology Topic

Functional monomerEmulsion +8

Examples

Experimental program(6)

Example Embodiment

[0018] The preparation method of the high-adhesion aqueous vinylidene chloride copolymer emulsion for metal surfaces of the present invention includes the following steps:

[0019] (1) Add vinylidene chloride, butyl acrylate, emulsifier and water into the pre-emulsification tank, stir and emulsify under ice bath conditions to obtain a pre-emulsion, wherein the mass percentage of vinylidene chloride and butyl acrylate is (75 ~85)%: (15-25)%, the emulsifier is sodium dodecyl sulfonate and alkyl glycoside, the amount is 1.0% to 2.5% of the total mass of vinylidene chloride and butyl acrylate, and the amount of water is partial 75% to 115% of the total mass of vinyl chloride and butyl acrylate;

[0020] (2) Add 20% of the mass of the pre-emulsion to the reactor, then add the molecular weight regulator and functional monomer, the reaction system is evacuated and filled with nitrogen, repeated three times, the reaction system is heated to 35°C, and the initiator persulfuric acid is added Potassium and sodium thiosulfate initiate a polymerization reaction at a constant temperature. After a period of reaction, the remaining pre-emulsion solution is added at one time, and the reaction is continued to prepare a vinylidene chloride copolymer emulsion.

[0021] The molecular weight regulator is one of 2-mercaptobutyric acid, ethyl 3-mercaptobutyrate, and 3-mercaptohexanol butyrate, and its dosage is 0.05% to 0.25 of the total mass of vinylidene chloride and butyl acrylate %.

[0022] The functional monomer is a combination of methacrylic acid, sodium 4-styrene sulfonate and 2-hydroxyethyl methacrylate phosphate. The amount of functional monomer is based on the total mass of vinylidene chloride and butyl acrylate. 3.5%~6.4%, the mass percentage of methacrylic acid, sodium 4-styrene sulfonate and 2-hydroxyethyl methacrylate phosphate is (25~35)%: (25~35)%: (35~ 45)%.

[0023] In the step (2), the polymerization process is divided into two stages. In the first stage, the 20% pre-emulsion and the functional monomer are copolymerized under the action of a molecular weight regulator, and the reaction is kept at a constant temperature for at least 3 hours. The emulsion is polymerized.

[0024] The amount of the emulsifier sodium dodecyl sulfonate and alkyl glycoside is 1.0% to 2.5% of the total mass of vinylidene chloride and butyl acrylate monomers, wherein the mass of sodium dodecyl sulfonate and alkyl glycoside An example of the percentage is (45-50)%: (50-55%), and the amount of water used is 85%-105% of the total mass of vinylidene chloride and butyl acrylate.

[0025] The vinylidene chloride copolymer emulsion has an emulsion-like appearance, a viscosity of 175-350 mPa·s at 25° C., a pH of 1.7-2.5, and a solid content of 50% to 55%.

[0026] The high-adhesion aqueous vinylidene chloride copolymer emulsion prepared by the method for preparing the high-adhesion aqueous vinylidene chloride copolymer emulsion for metal surfaces.

[0027] Among them, the mass percentage example of vinylidene chloride and butyl acrylate is preferably (78-82)%: (18-22)%, that is, the percentage example is "vinylidene chloride accounts for the total amount of vinylidene chloride and butyl acrylate Percentage: the percentage of butyl acrylate in the total mass of vinylidene chloride and butyl acrylate".

[0028] The molecular weight regulator is 2-mercaptobutyric acid, ethyl 3-mercaptobutyrate, 3-mercaptohexanol butyrate, and the amount used is preferably 0.15-0.22% of the total mass of vinylidene chloride and butyl acrylate monomers.

[0029] The functional monomers are methacrylic acid, sodium 4-styrene sulfonate and 2-hydroxyethyl methacrylate phosphate, and the amount used is preferably 4.5-5.0% of the total mass of vinylidene chloride and butyl acrylate monomers, Examples of the mass percentages of methacrylic acid, sodium 4-styrene sulfonate and 2-hydroxyethyl methacrylate phosphate are (25 to 35%): (25 to 35%): (35 to 45%), Preferably, it is (27-29)%: (30-32)%: (39-41)%.

[0030] The adhesion-enhancing aqueous vinylidene chloride copolymer resin prepared by the method of the invention has an emulsion appearance, a viscosity of 175-350 mPa·s (25° C.), a pH value of 1.7-2.5, and a solid content of 50-55%.

[0031] Diethylene glycol butyl ether is used as the film-forming aid, BYK346 is the leveling agent, which is added to the emulsion prepared according to the scheme of the present invention, wherein the added amount of the film-forming aid and leveling agent is 2 to 5% of the emulsion mass respectively And 0.25~0.35%, stir and disperse uniformly to prepare water-based vinylidene chloride varnish, spray it on the surface of sandblasted steel plate, with a wet film thickness of 120μm, bake at 60°C for 30 minutes, curing at room temperature for 7 days, and test the performance of the varnish film. Adhesion is 85kg·cm -2 ·A (GB/T 5210-1985), hardness of 1H (GB/T6739-1996), impact resistance of 50kg·cm (GB/T 1732-1993), salt spray test 600 hours, no blistering Rust (GB/T 1771-91).

Example Embodiment

[0032] Example 1

[0033] Dissolve 0.95g sodium dodecyl sulfonate and 1.00g alkyl glycoside in 100mL deionized water, stir until the emulsifier is completely dissolved, add 78.00g vinylidene chloride and 22.00g butyl acrylate under ice bath conditions, and emulsify with high speed stirring For 45 minutes, a pre-emulsion was obtained.

[0034] Secondly, 40.39g of the above-mentioned pre-emulsion was transferred to the reactor, and then 0.18g 2-mercaptobutyric acid, 1.26g methacrylic acid, 1.30g sodium 4-styrene sulfonate and 1.42g 2-hydroxyethyl methyl were added. Acrylate phosphate, fill the reactor with inert gas to eliminate oxygen (three times), increase the temperature to 35℃, add 0.25g potassium persulfate dissolved in 1mL water and 0.20g sodium thiosulfate dissolved in 1mL water, and polymerize at constant temperature For 3 hours, add the remaining pre-emulsified liquid at once, react at constant temperature for 7 hours, cool down, and filter out to obtain a vinylidene chloride copolymer emulsion: solid content is 51%, viscosity is 195mPa·s (25°C), and pH is 2.0. The average particle size is 125nm.

[0035] The vinylidene chloride copolymer emulsion in Example 1 was used to prepare water-based vinylidene chloride coating formulations, as shown in Table 1.

[0036] The preparation method is as follows:

[0037] First add No. 1 (emulsion in Example 1) and No. 2 raw materials into the mixing tank, stir at medium speed with a high-speed mixer for 30 minutes, then add raw materials 3-8 in order, stir for 45 minutes, and finally filter, discharge, and pack . The prepared water-based vinylidene chloride paint is gray, has no mechanical impurities, has a pH of ~2.5, a solid content of 62%, and a viscosity of 100 seconds (coating-4 cups). Spray the coating on the surface of the sandblasted steel plate, the sprayed wet film thickness is 120μm, dried and cured at 60°C to form a film, after curing at room temperature for 7 days, the adhesion is 55kg·cm -2 ·A (GB/T 5210-1985), no blistering and no rust on the board surface for 600 hours of salt spray resistance test (GB/T 1771-91).

[0038] Table 1 Water-based paint formula:

[0039] Serial number composition Mass percentage/% 1 The emulsion in Example 1 45.00 2 Pigment paste 50.00 3 Defoamer BYK028 0.15 4 Substrate wetting agent Tego270 0.25 5 Leveling agent Tego Glide410 0.25 6 Thickener Tego ViscoPlus 3000 0.50 7 Lauryl ester 1.50 8 Deionized water 2.35 total 100.00

Example Embodiment

[0040] Example 2

[0041] Dissolve 0.90g sodium dodecyl sulfonate and 0.95g alkyl glycoside in 90mL deionized water, stir until the emulsifier is completely dissolved, add 80.00g vinylidene chloride and 20.00g butyl acrylate under ice bath conditions, and emulsify with high speed stirring For 45 minutes, a pre-emulsion was obtained.

[0042] Secondly, 38.37g of the above-mentioned pre-emulsified liquid was transferred to the reactor, and then 0.20g ethyl 3-mercaptobutyrate, 1.45g methacrylic acid, 1.50g sodium 4-styrene sulfonate and 2.00g 2-hydroxyethyl methyl were added. Acrylate phosphate, fill the reactor with inert gas to eliminate oxygen, raise the temperature to 35°C, add 0.20g potassium persulfate dissolved in 1mL water and 0.18g sodium thiosulfate dissolved in 1mL water, polymerize at constant temperature for 4 hours, Add the remaining pre-emulsion at one time, react at a constant temperature for 6 hours, cool down, and filter to obtain a vinylidene chloride copolymer emulsion: solid content is 54%, viscosity is 265mPa·s (25°C), pH value is 2.5, average particle size It is 142nm.

[0043] Using the vinylidene chloride copolymer emulsion in Example 2, paint and plate according to the scheme of Example 1, with an adhesion of 83kg·cm -2 ·A (GB/T 5210-1985), no blistering and no rust on the surface of the salt spray test for 800 hours (GB/T 1771-91).

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PUM

Property	Measurement	Unit
Viscosity	175.0 ~ 350.0	mPa·s
Viscosity	0.0 ~ 195.0	mPa·s
The average particle size	125.0	nm
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Easy to migrate
Small molecular weight

High-adhesion water-based vinylidene chloride copolymer emulsion for metal surface and preparation method thereof

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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