CN100368445C - Preparation method and application of organosilicon acrylate/nanometer clay composite emulsion - Google Patents

Abstract

The invention discloses a method for preparing organosilicon acrylate/nanometer clay composite emulsion by in-situ emulsion polymerization and its application. Dissolve the reactive emulsifier in distilled water, then add clay, acrylate monomer and organosilicon monomer, stir and emulsify for 1 to 2 hours to obtain a stable emulsion; raise the temperature of the emulsion, and then make a solution made of initiator and distilled water Add it dropwise into the emulsion, react for 3-5 hours, raise the reaction temperature to 80-90°C, continue the reaction for 1-2 hours; then lower the temperature to 30-40°C, adjust the pH value to 8-9, and you can get organic Silicon acrylate/nano clay composite emulsion; the composite viscosity and thixotropy of the organosilicon acrylate/nano clay composite emulsion synthesized by the present invention are increased, the storage stability of the emulsion and the heat resistance of the coating film are improved, and the comprehensive performance of the coating is improved. Excellent, can be used in the preparation of high-grade exterior wall paint.

Description

Preparation method and application of organosilicon acrylate/nanometer clay composite emulsion

technical field

The invention relates to a method for preparing organosilicon acrylate/nanometer clay composite emulsion by in-situ emulsion polymerization and its application in the preparation of high-grade exterior wall paint.

Background technique

Since the beginning of the 21st century, the development and application of nanomaterials has become a research hotspot, and the application in coatings is one of many research directions. Nanoparticles have special properties such as surface effect, small size effect, quantum size effect, and macroscopic quantum tunneling effect. After they are used in coatings, the optical properties, magnetic properties, electrical properties, and mechanical properties of the coating can be significantly improved. Or display new functions, which can greatly improve the grade and market competitiveness of coating products.

New water-based coatings represented by silicone-modified acrylic resins are comparable to traditional solvent-based coatings in terms of film-forming properties, adhesion, and weather resistance. But silicone-acrylic emulsion also has some problems, for example, organosilicon monomer is easy to hydrolyze and cross-link in the emulsion system to form a gel, which reduces the yield and makes the film-forming property of the emulsion worse; the rheological properties of the system are poor, making coating, Coating is more difficult. The emergence and application of nanomaterials and nanotechnology have played a huge role in promoting the performance of latex coatings. Nanoclay has good thixotropy, thickening and thickening effects, and is often used as a coating additive to improve the thixotropy, viscosity and mechanical strength of the system, and can increase the stability of the coating.

At present, the methods for preparing nanoclay/polymer composites mainly include intercalation method, blending method, sol-gel method, in-situ polymerization method and radiation method. The in-situ polymerization method not only realizes the uniform dispersion of inorganic nanoparticles in the polymer matrix, but also maintains the nano-characteristics of the particles, and is a common method for preparing nanocomposite emulsions. Chinese invention patent applications "98103038" and "01133347" respectively reported the preparation of polystyrene/clay nanocomposites and polyacrylate/clay nanocomposites by in-situ emulsion polymerization. However, it does not relate to the composite emulsion of silicone acrylate and nanoclay.

Contents of the invention

In order to solve the deficiencies in the above-mentioned prior art, the primary purpose of the present invention is to provide a method for preparing silicone acrylate/nanoclay composite emulsion by in-situ emulsion polymerization. The composite emulsion prepared by this method not only improves the composite emulsion of the emulsion Viscosity and coating film heat resistance, and has many excellent properties.

Another object of the present invention is to provide the application of the above-mentioned preparation method in preparing high-grade exterior wall paint.

The object of the present invention is achieved through the following technical solutions: a preparation method of organosilicon acrylate/nano clay composite emulsion, comprising the following process steps and process conditions:

(1) Dissolve 2 to 3 parts of reactive emulsifier in 100 to 130 parts of distilled water, then add 0.5 to 2.5 parts of clay, 80 to 120 parts of acrylate monomer and 8 to 12 parts of silicone monomer, stir and emulsify for 1 ~2 hours, a stable emulsion was obtained.

(2) Raise the temperature of the emulsion system to 70-80°C, then add a solution made of 0.2-0.8 parts of initiator and 8-12 parts of distilled water dropwise into the emulsion, and after 3-5 hours of reaction, raise the reaction temperature to 80 ~90°C, continue to react for 1-2 hours; then lower the temperature to 30-40°C, and adjust the pH value to 8-9 with a pH regulator to obtain a silicone acrylate/nanoclay composite emulsion.

The above-mentioned substances are all measured in parts by weight.

In order to better realize the present invention, the reactive emulsifier in the step (1) is sodium alkyl vinyl sulfonate. The acrylate monomer is acrylic acid or methacrylic acid, alkyl methacrylate and alkyl acrylate; the alkyl methacrylate in the acrylate monomer is 46 to 51 parts, and the alkyl acrylate in the acrylate monomer is 48-53 parts of ester, 1 part of acrylic acid or methacrylic acid in the acrylate monomer; the alkyl methacrylate includes methyl methacrylate, ethyl methacrylate or butyl methacrylate, etc.; The alkyl acrylate includes methyl acrylate, ethyl acrylate or butyl acrylate. The clay is organically treated with quaternary ammonium salts. The organosilicon monomer is vinyltriethoxysilane or vinyltrimethoxysilane or the like. In the described step (2), the initiator is potassium persulfate or ammonium persulfate and the like. The pH regulator is a weak base such as ammonia or triethanolamine. The silicone acrylate/nanometer clay composite emulsion is transparent with blue light.

Application of the organosilicon acrylate/nanometer clay composite emulsion prepared by the above method in preparing high-grade exterior wall paint.

In the present invention, the clay organically treated with quaternary ammonium salt is selected as an inorganic component, dispersed in organosilicon monomers and acrylate monomers, and the organosilicon acrylate/nanometer clay composite emulsion is obtained through emulsion polymerization. The clay of the present invention is a class of non-metallic layered silicate minerals, the main structural units are silicon-oxygen tetrahedrons and aluminum-oxygen octahedrons arranged two-dimensionally, the two are connected by common oxygen atoms, and the inner surface of the clay layer has Negative charges, interlayer cations Na ⁺ , Mg ²⁺ , Ca ²⁺ etc. are exchangeable cations. The used nano-clay Claytone II of the present invention is the product of Rockwood Specialties company, is to be raw material with montmorillonite, through ion exchange reaction, makes quaternary ammonium chloride replace the sodium ion in raw material, thereby makes montmorillonite by hydrophilicity Inorganic clays become hydrophobic organoclays. The reactive emulsifier of the present invention is sodium alkyl vinyl sulfonate. Compared with the low molecular weight emulsifier, there are both hydrophilic and lipophilic emulsifying groups and functional groups that can participate in free radical polymerization in the molecular structure of the reactive emulsifier. group. In the process of emulsion polymerization, it not only acts as an emulsifier but also participates in the polymerization reaction of monomers to bind to the molecular chain of the emulsion polymer, and binds to the polymer chain by covalent bonds instead of physical adsorption. After the reaction, As a part of the copolymer, the stability to water and ultraviolet light is greatly improved; the dispersion medium for in-situ polymerization is water.

Compared with the prior art, the present invention has the following advantages and beneficial effects: the technical scheme of the present invention is simple in process, does not pollute the environment, the obtained nano-composite emulsion has higher viscosity and thixotropy, and the comprehensive performance of the coating is excellent.

Detailed ways

The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

Example 1

Dissolve 2 g of sodium alkyl vinyl sulfonate emulsifier in 120 ml of distilled water, then add 0.5 g of clay (Claytone II) (clay treated with quaternary ammonium salt), 100 g of acrylate monomer (acrylate monomer For methyl methacrylate, butyl acrylate and acrylic acid, the weight ratio of methyl methacrylate in the acrylate monomer: butyl acrylate: acrylic acid is 46:53: 1) and 10 grams of vinyltriethoxysilane, Stir and emulsify for 1 hour to obtain a stable emulsion, raise the temperature of the emulsion system to 80°C under normal pressure, add a solution made of 0.4 g of potassium persulfate and 10 ml of distilled water dropwise into the emulsion, react for 3 hours, and raise the reaction temperature to to 90°C and continue the reaction for 1 hour. After the reaction is finished, the temperature is lowered to 30-40° C., and the pH value is adjusted to 8-9 with ammonia water to obtain a transparent organosilicon acrylate/nano-clay composite emulsion with blue light. The properties of emulsion and coating film are shown in Table 1.

Example 2

With embodiment 1, wherein adding clay (Claytone II) (the clay of quaternary ammonium salt organic treatment) is 1.0 grams. The emulsion and coating properties of the composite emulsion are shown in Table 1.

Example 3

With embodiment 1, wherein adding clay (Claytone II) (the clay of quaternary ammonium salt organic treatment) is 1.5 grams. The emulsion and coating properties of the composite emulsion are shown in Table 1.

Example 4

With embodiment 1, wherein adding clay (Claytone II) (the clay of quaternary ammonium salt organic treatment) is 2.0 grams. The emulsion and coating properties of the composite emulsion are shown in Table 1.

Example 5

With embodiment 1, wherein adding clay (Claytone II) (the clay of quaternary ammonium salt organic treatment) is 2.5 grams. The emulsion and coating properties of the composite emulsion are shown in Table 1.

Example 6

Dissolve 2.5 grams of alkyl vinyl sulfonate sodium emulsifier in 120 milliliters of distilled water, then add 1.0 grams of clay (Claytone II) (clay treated with quaternary ammonium salts), 100 grams of acrylate monomer (acrylate monomer Ethyl methacrylate, methyl acrylate and methacrylic acid, the weight ratio of ethyl methacrylate in the acrylate monomer: methyl acrylate: methacrylic acid is 51:48:1) and 10 grams of vinyl triethyl Oxysilane, stirred and emulsified for 1 hour to obtain a stable emulsion, the emulsion system was heated to 70°C under normal pressure, and a solution made of 0.2 grams of potassium persulfate and 10 ml of distilled water was added dropwise to the emulsion and reacted for 3 hours. The reaction temperature was raised to 90°C and the reaction was continued for 1 hour. After the reaction is finished, the temperature is lowered to 30-40° C., and the pH value is adjusted to 8-9 with ammonia water to obtain a transparent organosilicon acrylate/nano-clay composite emulsion with blue light. The properties of emulsion and coating film are shown in Table 1.

Example 7

Dissolve 3 g of sodium alkyl vinyl sulfonate emulsifier in 120 ml of distilled water, then add 2.0 g of clay (Claytone II) (clay treated with quaternary ammonium salt), 100 g of acrylate monomer (acrylate monomer For butyl methacrylate, ethyl acrylate and acrylic acid, the weight ratio of butyl methacrylate in acrylate monomer: ethyl acrylate: acrylic acid is 50:49:1) and 10 grams of vinyltriethoxysilane, Stir and emulsify for 1 hour to obtain a stable emulsion, raise the temperature of the emulsion system to 80°C under normal pressure, add a solution made of 0.6 g of potassium persulfate and 10 ml of distilled water dropwise into the emulsion, react for 3 hours, and raise the reaction temperature to to 90°C and continue the reaction for 1 hour. After the reaction, the temperature is lowered to 30-40° C., and the pH value is adjusted to 8-9 with ammonia water to obtain a transparent organosilicon acrylate/nano-clay composite emulsion with blue light. The properties of emulsion and coating film are shown in Table 1.

Example 8

Dissolve 3 g of sodium alkyl vinyl sulfonate emulsifier in 120 ml of distilled water, then add 2.5 g of clay (Claytone II) (clay treated with quaternary ammonium salt), 100 g of acrylate monomer (acrylate monomer For methyl methacrylate, butyl acrylate and acrylic acid, the weight ratio of methyl methacrylate in the acrylate monomer: butyl acrylate: acrylic acid is 46:53: 1) and 10 grams of vinyltriethoxysilane, Stir and emulsify for 1 hour to obtain a stable emulsion, raise the temperature of the emulsion system to 80°C under normal pressure, add a solution made of 0.8 g of potassium persulfate and 10 ml of distilled water dropwise into the emulsion, react for 3 hours, and raise the reaction temperature to to 90°C and continue the reaction for 1 hour. After the reaction, the temperature was lowered to 35° C., and the pH value was adjusted to 8-9 with ammonia water to obtain a transparent organosilicon acrylate/nano-clay composite emulsion with blue light. The properties of emulsion and coating film are shown in Table 1.

Example 9

Dissolve 3 g of sodium alkyl vinyl sulfonate emulsifier in 130 ml of distilled water, then add 2.0 g of clay (Claytone II) (clay treated with quaternary ammonium salt), 80 g of acrylate monomer (acrylate monomer For butyl methacrylate, ethyl acrylate and acrylic acid, the weight ratio of butyl methacrylate in the acrylate monomer: ethyl acrylate: acrylic acid is 50:49:1) and 8 grams of vinyl triethoxysilane, Stir and emulsify for 1.5 hours to obtain a stable emulsion, raise the temperature of the emulsion system to 75°C under normal pressure, add a solution made of 0.6 g of ammonium persulfate and 10 ml of distilled water dropwise into the emulsion, react for 4 hours, and raise the reaction temperature to to 85°C and continue the reaction for 1 hour. After the reaction, the temperature was lowered to 40° C., and the pH value was adjusted to 8-9 with ammonia water to obtain a transparent organosilicon acrylate/nano-clay composite emulsion with blue light.

Example 10

Dissolve 3 g of sodium alkyl vinyl sulfonate emulsifier in 100 ml of distilled water, then add 2.5 g of clay (Claytone II) (clay treated with quaternary ammonium salt), 120 g of acrylate monomer (acrylate monomer For methyl methacrylate, butyl acrylate and acrylic acid, methyl methacrylate in the acrylate monomer: butyl acrylate: the weight ratio of acrylic acid is 46: 53: 1) and 12 grams of vinyltrimethoxysilane, stirring Emulsified for 2 hours to obtain a stable emulsion. The emulsion system was heated up to 70°C under normal pressure, and a solution made of 0.8 grams of potassium persulfate and 8 milliliters of distilled water was added dropwise to the emulsion, reacted for 5 hours, and the reaction temperature was raised to 80°C, the reaction was continued for 1 hour. After the reaction, the temperature was lowered to 30° C., and the pH value was adjusted to 8-9 with triethanolamine to obtain a transparent organosilicon acrylate/nano-clay composite emulsion with blue light.

comparative example

Dissolve 2 grams of alkyl vinyl sulfonate sodium emulsifier in 120 milliliters of distilled water, then add 100 grams of acrylate monomer (acrylate monomer is methyl methacrylate, butyl acrylate and acrylic acid, in acrylate monomer Methyl methacrylate: butyl acrylate: the weight ratio of acrylic acid is 46:53:1) and 10 grams of vinyltriethoxysilane, stirred and emulsified for 1 hour to obtain a stable emulsion, and the emulsion system was heated at normal pressure To 80°C, a solution made of 0.4 g of potassium persulfate and 12 ml of distilled water was added dropwise to the emulsion, and reacted for 3 hours, then the reaction temperature was raised to 90°C, and the reaction was continued for 1 hour. After the reaction, the temperature is lowered to below 40°C (30-40°C), and the pH value is adjusted to 8-9 with ammonia water to obtain a transparent silicone acrylate emulsion with blue light. The properties of emulsion and coating film are shown in Table 1.

Table 1 Silicone acrylate/nanoclay composite emulsion properties and coating properties

Adhesion (level) Impact strength (kg.cm) Flexibility (nm axis) Pencil hardness Gloss water resistance Alkali resistance Ca²⁺ stability Surface tension/mN/m Composite viscosity/Pa.s Thermal decomposition temperature (℃) Average particle size (nm) Comparative Examples 2 50 1 B 153.9 10d no exception pass pass 52.0 0.01 333 143 Example 1 1 50 1 B 181.6 10d no exception pass pass 47.7 0.10 350 146 Example 2 1 50 1 B 157.1 10d no exception pass pass 45.4 0.14 352 149 Example 3 1 50 1 B 162.4 10d no exception pass pass 41.6 0.15 355 150 Example 4 1 50 1 HB 181.9 10d no exception pass pass 41.5 0.80 356 149 Example 5 2 50 1 B 169.3 10d no exception pass pass 41.5 2.0 358 156 Example 6 1 50 1 B 170.5 10d no exception pass pass 44.9 0.15 353 151 Example 7 1 50 1 B 177.6 10d no exception pass pass 42.3 0.78 356 149 Example 8 2 50 1 B 168.7 10d no exception pass pass 41.8 1.18 359 153 Example 9 1 50 1 B 178.0 10d no exception pass pass 42.0 0.76 355 147 Example 10 2 50 1 B 167.7 10d no exception pass pass 41.8 2.20 360 157

Claims (8)

1. A preparation method of organosilicon acrylate/nanometer clay composite emulsion, comprising following process steps and process conditions: (1) Dissolve 2 to 3 parts of reactive emulsifier in 100 to 130 parts of distilled water, then add 0.5 to 2.5 parts of clay, 80 to 120 parts of acrylate monomer and 8 to 12 parts of silicone monomer, stir and emulsify for 1 ~2 hours, a stable emulsion is obtained; (2) Raise the temperature of the emulsion to 70-80°C, then add a solution made of 0.2-0.8 parts of initiator and 8-12 parts of distilled water dropwise into the emulsion, and after reacting for 3-5 hours, raise the reaction temperature to 80-80°C. 90°C, continue to react for 1-2 hours; then lower the temperature to 30-40°C, and adjust the pH value to 8-9 with a pH regulator to obtain a silicone acrylate/nano-clay composite emulsion; the clay is a quaternary ammonium salt Organically treated clay; the acrylate monomer in the step (1) is acrylic acid or methacrylic acid, alkyl methacrylate and alkyl acrylate; All the above-mentioned substances are measured in parts by weight. 2. The preparation method of the organosilicon acrylate/nanoclay composite emulsion according to claim 1, characterized in that: the reactive emulsifier in the step (1) is sodium alkyl vinyl sulfonate. 3. the preparation method of organosilicon acrylate/nano clay composite emulsion according to claim 1, is characterized in that: in described acrylate monomer, the alkyl methacrylate is 46～51 parts, and the alkyl acrylate is 48-53 parts, 1 part of acrylic acid or methacrylic acid. 4. the preparation method of silicone acrylate/nanometer clay composite emulsion according to claim 1, is characterized in that: described alkyl methacrylate is methyl methacrylate, ethyl methacrylate or methacrylic acid Butyl acrylate; the alkyl acrylate is methyl acrylate, ethyl acrylate or butyl acrylate. 5. the preparation method of organosilicon acrylate/nanometer clay composite emulsion according to claim 1, is characterized in that: in described step (1), organosilicon monomer is vinyltriethoxysilane or vinyltrimethoxy base silane. 6. The preparation method of the organosilicon acrylate/nanoclay composite emulsion according to claim 1, characterized in that: in the step (2), the initiator is potassium persulfate or ammonium persulfate. 7. The preparation method of the organosilicon acrylate/nanoclay composite emulsion according to claim 1, characterized in that: the pH regulator in the step (2) is ammonia water or triethanolamine. 8. The preparation method of the silicone acrylate/nano-clay composite emulsion according to claim 1, characterized in that: the silicone acrylate/nano-clay composite emulsion is transparent with blue light.