CN118813100A - Preparation technology of wear-resistant fluorinated silicone polyacrylate modified acrylic resin coating - Google Patents

Abstract

The invention belongs to the technical field of acrylic resins, and more particularly to the preparation process of wear-resistant fluorinated silicon polyacrylate modified acrylic resin coatings, using double-ended (2-bromoisobutyrate propyl) polysiloxane, cuprous bromide, 2,2'-bipyridyl, acrylate monomer, styrene-based perfluoroalkyl monomer, etc. as raw materials, to prepare fluorinated silicon polyacrylate. Adding to water-based acrylic resin, the compatibility between polysiloxane and acrylic resin can be improved, and polysiloxane is evenly dispersed in the acrylic resin coating matrix, improving the water resistance, salt spray resistance, impact resistance, flexibility and wear resistance of the coating. Fluorinated silicon polyacrylate contains a phenyl perfluoroalkyl structure, and a benzene ring has a large rigidity, which is introduced into a polysiloxane molecular chain, and has higher mechanical properties such as friction resistance, and the perfluoroalkyl structure can also improve the water resistance and salt spray resistance of acrylic resin coatings.

Description

Preparation technology of wear-resistant fluorinated silicone polyacrylate modified acrylic resin coating

Technical Field

The invention belongs to the technical field of acrylic resins, and in particular relates to a preparation process of a wear-resistant fluorine-containing silicon polyacrylate modified acrylic resin coating.

Background Art

Water-based acrylic resin coatings have fast curing speed, low pollution, excellent weather resistance, and are widely used. At present, the modification methods of acrylic resins are mainly copolymerization modification, blending modification, grafting modification, etc. For example, when acrylic resins are polymerized, adding functional monomers such as styrene, fluorine-containing monomers, silicon-containing monomers, etc. can improve the water resistance, salt spray resistance, mechanical properties, etc. of acrylic resin coatings. Alternatively, adding inorganic fillers or organic polymer fillers directly to acrylic resins can also improve the performance of acrylic resin coatings.

Polysiloxane is a kind of organic silicon polymer, which has the characteristics of high bond energy, high hardness, high thermal decomposition temperature, and good heat resistance, water resistance, corrosion resistance and wear resistance; it is widely used in acrylic resin, polystyrene, silicone rubber and other materials. However, the polarity difference between polysiloxane and acrylic resin is very large, and the two are incompatible. Usually, polysiloxane and acrylic resin are combined by chemical grafting or copolymerization.

Atom transfer radical polymerization (ATRP) has the advantages of wide applicable monomers, good controllability, high reaction activity, etc., and is mainly used to prepare polymers such as block copolymers and graft polymers. The present invention introduces fluorinated polyacrylate molecules at the end of polysiloxane in the ATRP polymerization reaction to improve the comprehensive performance of acrylic resin coatings.

Summary of the invention

1. Technical issues to be solved

In view of the deficiencies in the prior art, the present invention provides a preparation process for a wear-resistant fluorinated silicone polyacrylate-modified acrylic resin coating, which solves the problems of poor wear resistance and water resistance, poor mechanical properties, and the like of acrylic resin coatings.

(II) Technical solution

Preparation process of wear-resistant fluorinated silicone polyacrylate modified acrylic resin coating:

Step S1, add toluene, double-terminated (2-bromoisobutyrate propyl) polysiloxane, catalyst cuprous bromide, ligand 2,2'-bipyridine into a reaction bottle, introduce nitrogen to deoxygenate, then add acrylate monomer and the structural formula A styrene-based perfluoroalkyl monomer, wherein n is any integer from 4 to 8; then an ATRP polymerization reaction is carried out in a nitrogen atmosphere, after the reaction, the solution is poured into ethanol for precipitation, filtered, washed with ethanol, and dried to obtain a fluorinated silicone polyacrylate. The preparation reaction formula is as follows:

Step S2, adding water-based acrylic resin, fluorinated silicone polyacrylate, dispersant, and defoamer into water, and dispersing at high speed to obtain a wear-resistant fluorinated silicone polyacrylate modified acrylic resin coating.

Preferably, the mass of the acrylate monomer and the styrene perfluoroalkyl monomer in S1 are 30-70% and 25-60% of the mass of the double-terminated (2-bromoisobutyrate propyl) polysiloxane, respectively.

Preferably, the acrylate monomer is methyl acrylate or methyl methacrylate.

Preferably, the temperature of the ATRP polymerization reaction in S1 is 80-90° C., and the reaction time is 36-48 h.

Preferably, the mass of the fluorine-containing silicon polyacrylate in S2 is 5-30% of the mass of the water-based acrylic resin.

Preferably, the preparation process of double-terminal (2-bromoisobutyrate propyl) polysiloxane is as follows: add toluene, double-terminal hydroxypropyl silicone oil, 2-bromoisobutyl bromide, and catalyst triethylamine to a reaction bottle, wherein the mass of 2-bromoisobutyl bromide is 35-40% of the mass of double-terminal hydroxypropyl silicone oil; first react at 0-5°C for 30-60min, then react at 20-30°C for 24-36h, distill under reduced pressure, add water, stir and stand for stratification, separate and dry the oil phase to obtain double-terminal (2-bromoisobutyrate propyl) polysiloxane. The preparation reaction formula is as follows:

Preferably, the preparation process of the styrene-based perfluoroalkyl monomer is as follows: add chloroform, 3-isopropenyl-α,α-dimethylbenzyl isocyanate, perfluoroalkylethanol, and catalyst dibutyltin dilaurate to a reaction bottle, wherein the mass of perfluoroalkylethanol is 125-220% of the mass of 3-isopropenyl-α,α-dimethylbenzyl isocyanate; heat to 40-55°C, react for 3-6h, distill under reduced pressure, and recrystallize the product with chloroform to obtain a styrene-based perfluoroalkyl monomer. The preparation reaction formula is as follows:

Preferably, the structural formula of perfluoroalkylethanol is n is any integer between 4 and 8.

(III) Beneficial technical effects

The invention utilizes 2-bromoisobutyl bromide to react with the hydroxyl group of double-terminal hydroxypropyl silicone oil for esterification to obtain double-terminal (2-bromoisobutyrate propyl) polysiloxane, and uses the double-terminal (2-bromoisobutyrate propyl) polysiloxane as a macromolecular initiator to efficiently and controllably initiate methyl acrylate and styrene-based perfluoroalkyl monomers for ATRP atom transfer radical polymerization in a catalytic system of cuprous bromide catalyst and 2,2'-bipyridine ligand, thereby realizing the introduction of phenyl- and perfluoroalkyl-containing polyacrylate molecular chains at the end of the polysiloxane.

The present invention adds fluorinated silicone polyacrylate to acrylic resin coating, and the polysiloxane chain segment of the fluorinated silicone polyacrylate is grafted with the polyacrylate molecular chain, which significantly improves the compatibility between the polysiloxane and the acrylic resin. The polysiloxane has good flexibility, wear resistance, water resistance and corrosion resistance, and is evenly dispersed in the acrylic resin coating matrix, thereby improving the water resistance, salt spray resistance, impact resistance, flexibility and wear resistance of the coating.

The polysiloxane grafted polyacrylate molecular chain of the present invention contains a phenyl perfluoroalkyl structure. The benzene ring has greater rigidity and is introduced into the polysiloxane molecular chain to make the polysiloxane have higher mechanical properties such as friction resistance. At the same time, the perfluoroalkyl structure can also improve the water resistance and salt spray resistance of the acrylic resin coating.

DETAILED DESCRIPTION

The acrylic resin in the embodiment of the present invention is of the brand J-676. The anti-dispersant is an organic silicon dispersant of the brand BYK-346; the defoamer is of the brand XH-5020.

The structural formula of double-terminal hydroxypropyl silicone oil is: Hubei Langbowan Biopharmaceuticals, catalog number LBW-0094.

Example 1

(1) Add 60 mL of toluene, 6 g of double-terminal hydroxypropyl silicone oil, 2.3 g of 2-bromoisobutyl bromide, and 1.4 g of catalyst triethylamine to a reaction bottle, react at 0°C for 60 min, then react at 25°C for 24 h, distill under reduced pressure, add water, stir and stand to separate, separate and dry the oil phase to obtain double-terminal (2-bromoisobutyrate propyl) polysiloxane.

(2) Add 15 mL of chloroform, 2 g of 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and 2.5 g of perfluorobutyl alcohol (structural formula: CAS No. 2043-47-2), 0.14g catalyst dibutyltin dilaurate, heated to 40°C, reacted for 5h, distilled under reduced pressure, and the product was recrystallized with chloroform to obtain a styrene-based perfluoroalkyl monomer. The structural formula is

(3) 80 mL of toluene, 10 g of double-terminated (2-bromoisobutyrate propyl) polysiloxane, 11 mg of catalyst cuprous bromide, and 26 mg of ligand 2,2'-bipyridine were added to the reaction bottle, and nitrogen was introduced to deoxygenate. Then, 3 g of methyl methacrylate and 2.5 g of styrene-based perfluoroalkyl monomer were added. Then, ATRP polymerization was carried out at 80 ° C in a nitrogen atmosphere for 36 h. After the reaction, the solution was poured into ethanol for precipitation, filtered, washed with ethanol, and dried to obtain fluorinated silicone polyacrylate.

(4) Add 100 g of water-based acrylic resin, 5 g of fluorinated silicone polyacrylate, 0.2 g of dispersant, and 0.6 g of defoamer into 200 mL of water, and disperse at high speed to obtain a wear-resistant fluorinated silicone polyacrylate-modified acrylic resin coating.

Example 2

(1) Add 80 mL of toluene, 6 g of double-terminal hydroxypropyl silicone oil, 2.4 g of 2-bromoisobutyl bromide, and 1.1 g of catalyst triethylamine to a reaction bottle, react at 0°C for 60 min, then react at 20°C for 36 h, distill under reduced pressure, add water, stir and stand to separate, separate and dry the oil phase to obtain double-terminal (2-bromoisobutyrate propyl) polysiloxane.

(2) Add 20 mL of chloroform, 2 g of 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and 3.5 g of perfluorohexylethanol (structural formula: CAS number is 647-42-7), 0.12g of catalyst dibutyltin dilaurate, heated to 55°C, reacted for 3h, distilled under reduced pressure, and the product was recrystallized with chloroform to obtain a styrene-based perfluoroalkyl monomer. The structural formula is

(3) 100 mL of toluene, 10 g of double-terminated (2-bromoisobutyrate propyl) polysiloxane, 19 mg of cuprous bromide catalyst, and 44 mg of ligand 2,2'-bipyridine were added to a reaction flask, and nitrogen was introduced to deoxygenate. Then, 5 g of methyl methacrylate and 4.2 g of styrene-based perfluoroalkyl monomer were added. Then, ATRP polymerization was carried out at 90 ° C in a nitrogen atmosphere for 36 h. After the reaction, the solution was poured into ethanol for precipitation, filtered, washed with ethanol, and dried to obtain fluorinated silicone polyacrylate.

(4) Add 100 g of water-based acrylic resin, 20 g of fluorinated silicone polyacrylate, 0.5 g of dispersant, and 0.3 g of defoamer into 200 mL of water, and disperse at high speed to obtain a wear-resistant fluorinated silicone polyacrylate-modified acrylic resin coating.

Example 3

(1) Add 50 mL of toluene, 6 g of double-terminal hydroxypropyl silicone oil, 2.1 g of 2-bromoisobutyl bromide, and 1.3 g of catalyst triethylamine to a reaction bottle, react at 5° C. for 30 min, then at 30° C. for 24 h, distill under reduced pressure, add water, stir and stand to separate, separate and dry the oil phase to obtain double-terminal (2-bromoisobutyrate propyl) polysiloxane.

(2) Add 20 mL of chloroform, 2 g of 3-isopropenyl-α, α-dimethylbenzyl isocyanate, and 4.4 g of perfluorooctylethanol (structural formula: CAS No. 678-39-7), 0.12g catalyst dibutyltin dilaurate, heated to 50°C, reacted for 6h, distilled under reduced pressure, and the product was recrystallized with chloroform to obtain a styrene perfluoroalkyl monomer. The structural formula is

(3) 130 mL of toluene, 10 g of double-terminated (2-bromoisobutyrate propyl) polysiloxane, 25 mg of cuprous bromide catalyst, and 63 mg of ligand 2,2'-bipyridine were added to the reaction flask, and nitrogen was introduced to deoxygenate. Then, 7 g of methyl acrylate and 6 g of styrene-based perfluoroalkyl monomer were added. Then, ATRP polymerization was carried out at 80 ° C in a nitrogen atmosphere for 48 h. After the reaction, the solution was poured into ethanol for precipitation, filtered, washed with ethanol, and dried to obtain fluorinated silicone polyacrylate.

(4) Add 100 g of water-based acrylic resin, 30 g of fluorinated silicone polyacrylate, 0.2 g of dispersant, and 0.8 g of defoamer into 200 mL of water, and disperse at high speed to obtain a wear-resistant fluorinated silicone polyacrylate-modified acrylic resin coating.

The difference between Comparative Example 1 and Example 1 is that no fluorine-containing silicone polyacrylate is added to the acrylic resin.

(1) Add 100 g of water-based acrylic resin, 5 g of fluorinated silicone polyacrylate, 0.2 g of dispersant, and 0.6 g of defoamer to 200 mL of water, and disperse at high speed to obtain an acrylic resin coating.

The difference between Comparative Example 2 and Example 1 is that double-terminal hydroxypropyl silicone oil is added to the acrylic resin.

(1) Add 100 g of water-based acrylic resin, 5 g of double-terminal hydroxypropyl silicone oil, 0.2 g of dispersant, and 0.6 g of defoamer to 200 mL of water, and disperse at high speed to obtain a modified acrylic resin coating.

The difference between Comparative Example 3 and Example 1 is that no styrene perfluoroalkyl monomer is added when preparing the silicon-containing polyacrylate.

(1) Add 80 mL of toluene, 10 g of double-terminated (2-bromoisobutyrate propyl) polysiloxane, 11 mg of cuprous bromide catalyst, and 26 mg of ligand 2,2'-bipyridine into a reaction flask, introduce nitrogen to deoxygenate, then add 3 g of methyl methacrylate, and then carry out ATRP polymerization reaction at 80°C in a nitrogen atmosphere for 36 hours. After the reaction, pour the solution into ethanol for precipitation, filter, wash with ethanol, and dry to obtain silicon-containing polyacrylate.

(2) Add 100 g of water-based acrylic resin, 5 g of silicon-containing polyacrylate, 0.2 g of dispersant, and 0.6 g of defoamer into 200 mL of water, and disperse at high speed to obtain a wear-resistant silicon-containing polyacrylate-modified acrylic resin coating.

The difference between Comparative Example 4 and Example 1 is that when preparing fluorine-containing silicon polyacrylate, hexafluorobutyl acrylate (structural formula: ) instead of the styryl perfluoroalkyl monomer.

(1) Add 80 mL of toluene, 10 g of double-terminated (2-bromoisobutyrate propyl) polysiloxane, 11 mg of catalyst cuprous bromide, and 26 mg of ligand 2,2'-bipyridine into a reaction flask, introduce nitrogen to deoxygenate, then add 3 g of methyl methacrylate and 2.5 g of hexafluorobutyl acrylate, and then carry out ATRP polymerization reaction at 80°C in a nitrogen atmosphere for 36 hours. After the reaction, pour the solution into ethanol for precipitation, filter, wash with ethanol, and dry to obtain fluorinated silicone polyacrylate.

(2) Add 100 g of water-based acrylic resin, 5 g of fluorinated silicone polyacrylate, 0.2 g of dispersant, and 0.6 g of defoamer into 200 mL of water, and disperse at high speed to obtain a wear-resistant fluorinated silicone polyacrylate-modified acrylic resin coating.

The coating is poured on the surface of the substrate, the curing temperature is 70℃, and the curing time is 8h. Water resistance is tested according to GB/T1733-1993. The impact resistance of the paint film is tested according to GB/T 1732-2020. Salt spray resistance is tested with reference to GB/T1771-2007. Flexibility is tested according to GB/T 1731-2020.

Pour the coating on the tinplate surface and cure it at 70℃ for 8h to make a paint film sample. Use a paint film abrasion tester to test the wear resistance of the paint film. The weight is 500g, the wear speed is 100r/min, and the number of wear turns is 200. Record the wear loss mass △m. △m＝m ₁ -m ₂ . m ₁ is the mass of the paint film sample before wear. m ₁ is the mass of the paint film sample after wear. The smaller the wear loss mass, the better the wear resistance. The test results are shown in the following table.

It can be seen from the above table that Comparative Example 1 is an ordinary acrylic resin coating with water resistance ≧432h, salt spray resistance ≧336, impact resistance of 20cm, flexibility of 2mm, and abrasion loss mass of 68.5mg.

Fluorine-containing silicon polyacrylate is added in each embodiment, and the water-resistant time and salt-fog-resistant time are improved, and the impact resistance reaches 50-60mm, the flexibility is 0.5-1mm, and the wear loss quality also decreases significantly, showing excellent water-resistant and salt-fog-resistant performance, as well as good mechanical properties and wear resistance. Mainly attributed to the polysiloxane segment grafted with the polyacrylate molecular chain in the fluorine-containing silicon polyacrylate, the compatibility between polysiloxane and acrylic resin is significantly improved, and polysiloxane has good flexibility, wear resistance and water-resistant and anti-corrosion properties, and is evenly dispersed in the acrylic resin coating matrix, improving the water resistance, salt-fog resistance, impact resistance, flexibility and wear resistance of the coating. And the polyacrylate molecular chain grafted with polysiloxane contains a phenyl perfluoroalkyl structure, and the benzene ring has a large rigidity, which is introduced into the polysiloxane molecular chain, so that the polysiloxane has higher mechanical properties such as friction resistance, and the perfluoroalkyl structure can also improve the water resistance and salt-fog resistance of the acrylic resin coating.

In Comparative Example 2, double-terminal hydroxypropyl silicone oil is added to the acrylic resin. The polarity of the silicone oil and the acrylic resin is very different, and the two are incompatible. Compared with Comparative Example 1, the double-terminal hydroxypropyl silicone oil cannot effectively improve the water resistance, salt spray resistance, impact resistance, flexibility and wear resistance of the acrylic resin.

In Comparative Example 3, when preparing the silicon-containing polyacrylate, no styrene perfluoroalkyl monomer is added, and the silicon-containing polyacrylate does not contain a phenyl perfluoroalkyl structure, resulting in the acrylic resin coating having lower water resistance and abrasion resistance than Example 1.

In Comparative Example 4, when preparing fluorinated silicone polyacrylate, hexafluorobutyl acrylate was used instead of styrene-based perfluoroalkyl monomer. The obtained fluorinated silicone polyacrylate did not contain a rigid benzene ring structure, and the abrasion loss mass of the acrylic resin coating was greater than that of Example 1, and the wear resistance was poor.

Claims (10)

1. The preparation process of the wear-resistant fluorine-containing silicon polyacrylate modified acrylic resin coating is characterized by comprising the following steps of:

S1, adding toluene, double-end (2-bromoisobutyric acid ester propyl) polysiloxane, cuprous bromide and 2,2' -bipyridine into a reaction bottle, introducing nitrogen to remove oxygen, and then adding an acrylic ester monomer, wherein the structural formula is Wherein n is any integer from 4 to 8; then carrying out ATRP polymerization reaction in a nitrogen range, precipitating after the reaction, filtering, washing and drying to obtain fluorine-containing silicon polyacrylate;

and S2, adding the aqueous acrylic resin, the fluorine-containing silicon polyacrylate, the dispersing agent and the defoaming agent into water, and dispersing at high speed to obtain the wear-resistant fluorine-containing silicon polyacrylate modified acrylic resin coating.

2. The preparation process of the wear-resistant fluorine-containing silicon polyacrylate modified acrylic resin coating according to claim 1, wherein the mass of the acrylic monomer and the styrene-based perfluoroalkyl monomer in the S1 is 30-70% and 25-60% of the mass of double-end (2-bromoisobutyric acid ester propyl) polysiloxane respectively.

3. The process for preparing the wear-resistant fluorine-containing silicon polyacrylate modified acrylic resin coating according to claim 2, wherein the acrylic monomer is methyl acrylate or methyl methacrylate.

4. The process for preparing the wear-resistant fluorine-containing silicon polyacrylate modified acrylic resin coating according to claim 1, wherein the temperature of the ATRP polymerization reaction in S1 is 80-90 ℃ and the reaction time is 36-48h.

5. The process for preparing the wear-resistant fluorine-containing silicon polyacrylate modified acrylic resin coating according to claim 1, wherein the mass of the fluorine-containing silicon polyacrylate in the S2 is 5-30% of the mass of the aqueous acrylic resin.

6. The process for preparing the wear-resistant fluorosilicone polyacrylate modified acrylic resin paint according to claim 2, wherein the process for preparing the double-ended (2-bromoisobutyric acid ester propyl) polysiloxane is as follows: toluene, double-end hydroxypropyl silicone oil, 2-bromoisobutyl acyl bromide and triethylamine are added into a reaction bottle, the reaction is carried out for 30 to 60 minutes at 0 to 5 ℃, then the reaction is carried out for 24 to 36 hours at 20 to 30 ℃, the reduced pressure distillation, the separation and the drying are carried out, and the double-end (2-bromoisobutyric acid ester propyl) polysiloxane is obtained.

7. The process for preparing the wear-resistant fluorine-containing silicon polyacrylate modified acrylic resin coating according to claim 6, wherein the mass of the 2-bromoisobutyl acyl bromide is 35-40% of the mass of the double-end hydroxypropyl silicone oil.

8. The process for preparing the wear-resistant fluorinated silicone polyacrylate modified acrylic resin coating according to claim 2, wherein the process for preparing the styryl perfluoroalkyl monomer is as follows: adding chloroform, 3-isopropenyl-alpha, alpha-dimethylbenzyl isocyanate, perfluoroalkyl alcohol and dibutyl tin dilaurate into a reaction bottle, heating to 40-55 ℃, reacting for 3-6h, distilling under reduced pressure, and recrystallizing to obtain styryl perfluoroalkyl monomers.

9. The process for preparing a wear-resistant fluorosilicone polyacrylate modified acrylic resin paint according to claim 8, wherein the mass of the perfluoroalkyl alcohol is 125-220% of the mass of the 3-isopropenyl-alpha, alpha-dimethylbenzyl isocyanate.

10. The process for preparing the wear-resistant fluorinated silicone polyacrylate modified acrylic resin coating according to claim 9, wherein the structural formula of the perfluoroalkyl alcohol isN is any integer from 4 to 8.