CN105693939A - Preparation method of SMA modified cationic acrylate emulsion for primers - Google Patents

Abstract

The invention relates to a preparation method of SMA modified cationic acrylate emulsion for primer, which mainly comprises imidized SMA quaternary ammonium salt, carboxyl-containing acrylic acid monomer, hydroxyl-containing acrylic acid monomer, free-radical polymerized acrylic acid The monomer is formed by cationic microemulsion; the SMA modified cationic acrylate emulsion for the primer prepared by the present invention can effectively improve the temperature resistance and alkali resistance of the paint film due to the introduction of imidized SMA functional resin , wear resistance, compatibility, water resistance and excellent adhesion, and the particle size of the emulsion reaches the nanometer level (≤150nm), so the modified cationic acrylate emulsion is a nano-microemulsion with strong penetration It can react with alkaline substances to form a coating film with high density and strong sealing ability, which can effectively improve the pan-alkali resistance and salting-out resistance of the coating film; it is widely used in sealing primers for interior and exterior walls and water-based wood sealing Primer, water-based ink, sizing agent, adhesive, etc.

Description

A kind of preparation method of SMA modified cationic acrylate emulsion for primer

technical field

The invention relates to a preparation method of a modified acrylate emulsion, in particular to an SMA modified cationic acrylate emulsion for a primer.

Background technique

Ordinary acrylic sealing primers are generally prepared from anionic emulsions. At present, acrylic copolymer emulsions widely used in China usually use methacrylic acid as a monomer to enhance adhesion, but there are some problems such as poor adhesion and weak alkali resistance. Disadvantages: The emulsifiers used are usually sodium lauryl sulfate and nonylphenol polyoxyethylene ether, and the particle size of the emulsion produced by anion is relatively large (generally, the particle size of the emulsion is 0.1-10 μm), and the surface tension is very large , it is difficult to penetrate into the small capillary pores inside the substrate, so the effect of the back cover can only be achieved by relying on the compactness of the coating film on the surface of the substrate; the film-forming mechanism of the acrylic sealing primer belongs to physical film-forming, and polymers cannot The chemical reaction to form a film is only based on the evaporation of its own water, and the polymer particles are softened under the action of the film-forming additives and then extruded to form a film, so the paint film is not tight, and the gaps are larger and more (good air permeability); The air permeability of the latex paint film also becomes the factor for the occurrence of paint film disadvantages such as alkali return and salting out. After being sprayed with water, the water penetrates into the paint film and dissolves the soluble salt and soluble alkali at the same time. The water migrates to the surface of the substrate and reacts with CO ₂ to form salts. During the migration process, as the water evaporates, the dissolved substances continue to crystallize and precipitate. If the crystals are between the paint film and the substrate, it will easily lead to the peeling off of the paint film. If it crystallizes on the surface of the paint film, it will form efflorescence and salting out.

The use of cationic acrylic sealing primer has small surface tension and strong permeability to the substrate. Both alkaline substances and temperature can promote the cross-linking reaction of cationic emulsion, so the new wall surface with strong alkalinity will make it more effective. Good film-forming effect can play a better sealing effect and improve the alkali resistance and salting-out resistance of the coating film.

CN102050918B discloses a soap-free emulsion polymerization method of a cationic polyacrylate finishing agent, using diallyl dimethyl ammonium chloride as an emulsifier, butyl acrylate and methyl methacrylate to prepare a cationic polyacrylate by soap-free emulsion polymerization Acrylic leather finishing agent, the latex particle size of the emulsion is about 800nm; it is applied in the leather finishing process, and the tensile strength, water absorption, dry and wet rubbing fastness of the leather are comparable to those of the commercially available cationic polyacrylate emulsion. Similar to leather but with increased elongation at break.

CN103265655A discloses a reactive cationic polyacrylate emulsion and its preparation method and application, belonging to the field of papermaking technology and printing and packaging technology; including styrene accounting for 40-45% of the total monomer amount, and butyl acrylate accounting for the total monomer amount 40-45% of total monomers, acrylamide accounts for 5-12% of total monomers, diallyl dimethyl ammonium chloride accounts for 5-12% of total monomers, protective colloid polyvinyl alcohol accounts for total monomers 0.1-0.6% of total monomers, cetyltrimethylammonium chloride accounts for 1-5% of total monomers, alkylphenol polyoxyethylene ether-10 accounts for 1-5% of total monomers, allyl oxide 5-9% nonylphenol polyoxyethylene, and 0.5-1.2% initiator potassium persulfate to prepare cationic polyacrylate emulsion; the reactive cationic polyacrylate emulsion of the present invention has good stability and can improve paper strength And paper water resistance.

CN101475661B discloses the preparation of a kind of fluorosilicone/or oil-modified acrylate copolymer cationic emulsion, and this emulsion is by acrylate alkyl ester and (meth) acrylate alkyl ester, ethylene carbonate, comprises aromatic substituted olefin, functional monomer : such as N-hydroxyalkylacrylamide, fluoroalkyl (meth)acrylate, vinyl/or acryloyloxyethyltrialkoxysilane or polymerizable acryloyloxyalkylurethane oil, (meth) Base) acryloyloxyethyl trialkyl ammonium chloride or (meth) dimethylaminoethyl acrylate and crosslinking agent, etc., in the presence of cationic surfactants and nonionic surfactants, obtained by emulsion polymerization . The cationic emulsion has excellent performance and is widely used in paper products, plastics, leather finishing agents and high-grade paints.

Contents of the invention

Imidated SMA quaternary ammonium salt is a polymerizable cationic polymer surfactant, which has good reactivity with active monomers such as styrene and acrylic monomers; cationic/nonionic microemulsion polymerization is used to introduce acyl Imidated SMA functional resin, modified cationic acrylate emulsion can effectively improve the temperature resistance, alkali resistance, abrasion resistance, compatibility, water resistance and excellent adhesion of the paint film, and the particle size of the emulsion It reaches the nanoscale (≤150nm), so the imidized SMA cationic acrylate emulsion is a nano-microemulsion with strong permeability and can react with alkaline substances to form a coating with high density and sealing Strong, can effectively improve the pan-alkali resistance and salting-out resistance of the coating film.

In order to solve the technical problems described above, the present invention takes the following technical solutions: the present invention relates to a SMA modified cationic acrylate emulsion for a primer, which consists of: 7% to 15% of imidized SMA quaternary ammonium salt, Carboxyl-containing acrylic monomer 2-8%, hydroxyl-containing acrylic monomer 2-8%, radical polymerized acrylic monomer 20-40%, OP-10 emulsifier 1-4%, cationic initiator 0.2-0.6 %, 50-65 parts of deionized water.

Wherein, the carboxyl-containing acrylic acid monomer is one of acrylic acid or methacrylic acid; the hydroxyl-containing acrylic monomer is 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxy acrylate At least one of -hydroxybutyl ester, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate or N-methylolacrylamide; the The free radical polymerized acrylic monomer is at least two or more of methyl methacrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, acrylonitrile, acrylamide or dimethylaminoethyl methacrylate monomer.

The cationic initiator is one of azobisisobutylamidine hydrochloride (AIBA) and azobisisobutylimidazoline hydrochloride (AIBI).

The present invention proposes a kind of preparation method of the SMA modified cationic acrylate emulsion that primer is used, and its preparation method comprises the steps:

a. In a reaction vessel equipped with a speed-regulating stirrer, a reflux tube, a dropping funnel and a thermometer, add imidized SMA quaternary ammonium salt, 20-30% of mixed monomers, and OP-10 emulsifier according to the formula and 60-80% deionized water, heated to 60°C until completely dissolved, and emulsified under high-speed stirring to obtain a pre-emulsion;

b. Fill in N ₂ , heat up to 80°C, and add 20% cationic initiator aqueous solution (3% mass ratio) dropwise under stirring at a certain speed, and react for 0.5-1h;

c. Keep the temperature at 81-83°C, add the remaining 70-80% of the mixed monomer and the remaining 80% of the ion initiator aqueous solution dropwise at a constant speed. React for 0.5 hours, cool down to 60°C, add the remaining water, cool to 40°C, filter and package, and obtain SMA-modified cationic acrylate emulsion for primer with a solid content of 40±2% and a particle size of ≤150nm.

The SMA modified cationic acrylic ester emulsion that the primer that the present invention makes is used, owing to introducing imidization SMA functional resin, can effectively improve the temperature resistance of paint film, alkali resistance, abrasion resistance, compatibility, Water resistance and excellent adhesion, and the particle size of the emulsion reaches the nanometer level (≤150nm), so the modified cationic acrylate emulsion is a nano-microemulsion, which has strong permeability and can react with alkaline substances , the formed coating film has high density and strong sealability, which can effectively improve the pan-alkali resistance and salt-out resistance of the coating film; it is widely used in interior and exterior wall sealing primers, water-based wood sealing primers, water-based inks, and sizing agents , Adhesives, etc.

detailed description

EXAMPLES Materials were prepared according to the component formulations in Table 1.

Table 1: three embodiment component formulations (mass parts)

raw material name Example 1 Example 2 Example 3 Methyl methacrylate 20 19 20 Imidated SMA quaternary ammonium salt 8.6 9.5 10 Butyl acrylate 6.8 7.2 6.4 Methacrylate 2.4 - 2.4 acrylic acid - 2.4 -

2-Hydroxyethyl Acrylate - 2.8 - N-Methylolacrylamide 2.6 - 2.4 Emulsifier OP-10 2.0 2.0 2.0 AIBA - - 0.3 AIBI 0.3 0.3 - Deionized water 57.3 56.8 56.5

Example 1:

The present invention proposes a kind of preparation method of the SMA modified cationic acrylate emulsion that primer is used, and its preparation method comprises the steps:

a. In a reaction vessel equipped with a speed-regulating stirrer, a reflux pipe, a dropping funnel and a thermometer, add 8.6 parts of imidized SMA quaternary ammonium salt, 25% of mixed monomers, 2 parts of OP-10 emulsifier and 70% deionized water, heated to 60°C until completely dissolved, and emulsified under high-speed stirring to obtain a pre-emulsion;

b. Fill with N ₂ , raise the temperature to 80°C, add 2 parts of AIBI aqueous solution (3% mass ratio) dropwise under stirring at a certain speed, and react for 0.5 to 1 hour;

c. Keep the temperature at 81-83°C, add the remaining 75% of the mixed monomer and the remaining 8 parts of AIBI aqueous solution dropwise at a uniform speed, and after the drop is completed within 1.5-2hr, raise the temperature to 88°C, and keep the temperature for 0.5hr. Cool down to 60°C, add the remaining water, cool to 40°C, filter and package, and obtain a SMA-modified cationic acrylate emulsion for primers with a solid content of 40.7%, a particle size of ≤128nm, and a pH value of 5.0.

The preparations of Example 2 and Example 3 were carried out with reference to the steps in Example 1.

The basic properties of the SMA-modified cationic acrylate emulsion used for the primer prepared by the present invention were tested according to relevant national standards, and the test results are shown in Table 2.

Table 2: Properties of SMA-modified cationic acrylate emulsions for primers

The SMA-modified cationic acrylate emulsion used in the primers prepared in the three embodiments and the cationic acrylate emulsion (comparative example) on the market are made into coating films, which are detected according to relevant national standards, and the coating film properties are compared and tested , and the test results are shown in Table 3.

Table 3: Film Properties of Cationic Acrylate Emulsion

Although the present invention has been described in detail and examples have been cited, for those of ordinary skill in the art, it is obvious that various solutions, modifications and changes that can be made according to the above description should be included within the scope of the claims .

Claims (4)

1. A SMA-modified cationic acrylate emulsion for primer, characterized in that: it consists of: 7-15% of imidized SMA quaternary ammonium salt, 2-8% of carboxyl-containing acrylic acid monomer, hydroxyl-containing 2-8% of acrylic acid monomer, 20-40% of free-radical polymerized acrylic monomer, 1-4% of OP-10 emulsifier, 0.2-0.6% of cationic initiator, and 50-65 parts of deionized water. 2. the SMA modified cationic acrylate emulsion that a kind of primer as claimed in claim 1 is used is characterized in that: the described acrylic acid monomer containing carboxyl is a kind of acrylic acid or methacrylic acid; The acrylic acid monomer of hydroxyl group is 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, At least one of 2-hydroxybutyl methacrylate or N-methylol acrylamide; the free radical polymerized acrylic monomer is methyl methacrylate, ethyl methacrylate, butyl acrylate, methyl acrylate At least two or more monomers of butyl acrylate, acrylonitrile, acrylamide or dimethylaminoethyl methacrylate. 3. the SMA modified cationic acrylate emulsion that a kind of primer as claimed in claim 1 is used, is characterized in that: described cationic initiator is azobisisobutylamidine hydrochloride (AIBA) and azobis One of isobutimidazoline hydrochloride (AIBI). 4. the preparation method of the SMA modified cationic acrylate emulsion that a kind of primer as claimed in claim 1,2,3 is characterized in that: described preparation method comprises the steps: a. In a reaction vessel equipped with a speed-regulating stirrer, a reflux tube, a dropping funnel and a thermometer, add imidized SMA quaternary ammonium salt, 20-30% of mixed monomers, and OP-10 emulsifier according to the formula and 60-80% deionized water, heated to 60°C until completely dissolved, and emulsified under high-speed stirring to obtain a pre-emulsion; b. Fill in N ₂ , heat up to 80°C, and add 20% cationic initiator aqueous solution (3% mass ratio) dropwise under stirring at a certain speed, and react for 0.5-1h; c. Keep the temperature at 81-83°C, add the remaining 70-80% of the mixed monomer and the remaining 80% of the ion initiator aqueous solution dropwise at a constant speed. React for 0.5 hours, cool down to 60°C, add the remaining water, cool to 40°C, filter and package, and obtain SMA-modified cationic acrylate emulsion for primer with a solid content of 40±2% and a particle size of ≤150nm.