CN1337416A - Prepn process of fluororubber modified polyacrylate emulsion - Google Patents

Abstract

The present invention relates to a preparation method of fluorine rubber modified polyacrylate emulsion. Firstly, a monomer mixture composed of methyl methacrylate, butyl acrylate and acrylic acid is prepared, and fluorine rubber is dissolved in the above monomer mixture, and then Dissolve the co-emulsifier in the above mixture to form an oil phase for later use; dissolve the nonionic emulsifier and anionic emulsifier in water to form a water phase, mix the oil phase and water phase, and stir at a high speed to form a fine emulsion; in the fine emulsion Add the initiator to the container, under the protection of nitrogen, add the miniemulsion, deionized water and the initiator, then drop the miniemulsion with the initiator into the container, finally add the initiator, adjust the pH value, and obtain the fluorine Rubber modified polyacrylate emulsion. Because the present invention has good bonding force with the base material, the surface performance of the paint film after film formation is good, and there is no pollution. Therefore, it can be used for surface modification of substrates in areas where stain resistance, heat resistance, water resistance, chemical resistance and non-stick properties are required.

Description

A kind of preparation method of polyacrylate emulsion modified by fluorine rubber

Technical field:

The invention relates to a preparation method of a polyacrylate emulsion modified by fluororubber (vinylidene fluoride-hexafluoropropylene copolymer), and specifically provides a modified polyacrylate emulsion using fluororubber as a modifier The emulsion and its preparation method provide the properties of the paint film prepared by using the modified emulsion, and belong to the field of polymer materials.

Background technique:

Polyacrylate emulsion uses water as the medium, which has the advantages of low cost, safe use, and less environmental pollution. Its film-forming material has the characteristics of flexibility, weather resistance, and good viscosity. Therefore, it has been widely used as a building material in decoration and interior and exterior walls. in paint. However, with the rise of high-rise buildings in cities, the waterproof, antifouling and appearance of buildings have been paid more and more attention, and higher requirements have been put forward for building exterior wall coatings.

In addition to high strength, elasticity and adhesion, high-performance exterior wall coatings must also have high weather resistance, water resistance, acid and alkali resistance, pollution resistance and good air permeability. It meets the requirements of modern coatings, while ordinary polyacrylate emulsion coatings are far from meeting these requirements. To solve these problems, it is necessary to modify the emulsion to improve its performance.

Fluoropolymers have many excellent properties, such as outstanding weather resistance, water resistance, oil resistance, chemical corrosion resistance, etc., and their paint films have good mechanical properties. But there are also three shortcomings:

1. Generally, fluororesins are difficult to dissolve, and organic solvents are used to cause environmental pollution. For example, PVDF resin is easy to crystallize and difficult to dissolve. When it is used as a coating, it is dissolved in a strong polar solvent. Polychlorotrifluoroethylene and polytetrafluoroethylene are even more difficult to dissolve in general solvents. In order to comply with the new regulations limiting solvent release, the requirement to further reduce the use of organic solvents in coatings has promoted the development and application of new solvent-free coatings, which is also to overcome the shortcomings of insolubility in conventional fluoropolymer coatings.

2. High temperature sintering. When fluoropolymers are used as coatings, high temperature sintering is required to form a dense film. Therefore, its use is greatly limited, especially when it is used in large-scale equipment or in outdoor construction.

3. Expensive. Fluoropolymer coatings, especially fluorine-containing emulsion coatings that dry at room temperature, have excellent performance, but are expensive and their use is limited.

The currently reported fluoropolymer coatings are mainly polyvinylidene fluoride: such as US patents US 3,34,222, 3,324,069, 4,383,075, 4,557,977, etc., which dissolve polyvinylidene fluoride in an organic solvent and mix with polyacrylate resin , and form a film after curing at high temperature. Because a large amount of organic solvents are used to cause environmental pollution, and high temperature curing is required, which is not conducive to construction.

Invention content:

The purpose of this invention is to propose a kind of preparation method of the polyacrylate emulsion modified by fluororubber, and further improve the performance of polyacrylate coating with fluororubber modified polyacrylate emulsion, so that it has higher weather resistance, Solvent resistance and anti-staining properties, etc., and can prevent the influence of solvents on the environment, the performance of the prepared coating is excellent and the price is much lower than that of fluoropolymers.

The preparation method of the polyacrylate emulsion modified by fluorine rubber proposed by the present invention comprises the following steps:

1. Prepare a monomer mixture composed of methyl methacrylate, butyl acrylate and acrylic acid, the ratio of which is 1:1:0.05～0.1, and then dissolve the fluororubber in the above-mentioned monomer mixture according to the ratio of 1:5～50 by weight in the mixture of solids, and then according to the ratio of 1:200~250, dissolve the co-emulsifier in the above mixture to form the oil phase for later use; according to the ratio of 1:50~70, dissolve the nonionic emulsifier and anionic emulsifier in water to form an aqueous phase, wherein the ratio of the nonionic emulsifier to the anionic emulsifier is 1:0.5-2, then the oil phase and the water phase are mixed and stirred at room temperature for 5-20 minutes;

2. Use a high-speed mixer to stir the above mixture at high speed to form a fine emulsion;

3. Adding an initiator in the miniemulsion, wherein the ratio of the amount of the initiator added to the total fluororubber is 1: 5-30;

4. Under the protection of nitrogen, add the miniemulsion, deionized water and initiator of the second step above into the container, wherein the ratio of the total amount of fluororubber to the miniemulsion is 1:4-60, and the ratio of the total amount of fluororubber to the deionized The ratio of ionized water is 1:4-40, the ratio of the total amount of fluorine rubber to the initiator is 4-40:1, stir and heat up to 60-90°C, after 1-3 hours of reaction, within 1-3 hours , drop the miniemulsion in the third step above into the container at a constant speed from a constant pressure funnel, the ratio of the total amount of fluororubber to the miniemulsion is 1:4-60, after the addition is completed, add an initiator, the amount of which is fluorine 1/5-1/30 of the total amount of rubber, after 1-3 hours of heat preservation, add ammonia water to adjust the pH value to 7.5-9.5, which is the fluororubber modified polyacrylate emulsion.

In the present invention, in order to achieve fine emulsification, a co-emulsifier is used; examples of the co-emulsifier include surfactants such as cetane and cetyl alcohol, but are not limited thereto.

In the present invention, a nonionic surfactant is used as the emulsifier; examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and the like, but are not limited thereto. More specifically, examples of polyoxyethylene alkyl ethers include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, and the like; polyoxyethylene alkylphenyl ethers include polyoxyethylene nonylbenzene Base ether, polyoxyethylene octyl phenyl ether, etc.

In the present invention, an anionic surfactant is used as an emulsifier, and examples of the anionic surfactant include alkyl sulfate, alkyl sulfonate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkylbenzene base ether sulfates, etc., but are not limited to these. More specifically, examples of alkyl sulfates include sodium lauryl sulfate and sodium cetyl sulfate; examples of alkyl sulfonates include sodium lauryl sulfate and cetyl sulfonic acid. Sodium; Examples of polyoxyethylene alkyl ether sulfates include sodium polyoxyethylene lauryl ether sulfate and polyoxyethylene cetyl ether ammonium sulfate; Examples of polyoxyethylene alkyl phenyl ether sulfates include Sodium polyoxyethylene nonylphenyl ether sulfate, polyoxyethylene octylphenyl ether ammonium sulfate, etc.

In the composition of the present invention, the acrylate monomers include methyl methacrylate, butyl acrylate, glycidyl acrylate, acrylic acid, styrene, etc., but are not limited thereto.

In the composition of the present invention, the fluoropolymer used has better solubility in acrylate monomers. In addition to vinylidene fluoride-hexafluoropropylene-based elastomers, vinylidene fluoride-based elastomers such as vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene, hexafluoropropylene-ethylene-based elastomers, tetrafluoroethylene- Ethylene-based elastomers, etc., but not limited to these.

In the composition of the present invention, the initiators include persulfate, azo and organic peroxy initiators, but are not limited thereto.

Because the present invention has good bonding force with the base material, the surface performance of the paint film after film formation is good, and there is no pollution. Therefore, it can be used for surface modification of substrates in areas requiring stain resistance, heat resistance, water resistance, chemical resistance and non-stick properties. For example, it is used in water-resistant and oil-resistant agents for building exterior walls, textiles, and leather products. The method of the invention also has the characteristics of low synthesis cost, low environmental pollution, convenient operation, etc., and is suitable for industrial production.

Detailed ways:

The technology of the present invention will be further described below by way of examples.

Embodiment 1: Preparation 1 of modified emulsion

Dissolve 1.0 g of fluororubber in a monomer mixture made of 20 g of methyl methacrylate, 20 g of butyl acrylate and 1.5 g of acrylic acid, and dissolve 0.2 g of oil-soluble co-emulsifier hexadecane in the above mixture to form Oil phase; dissolve 0.5 g of octylphenol polyoxyethylene ether and 0.5 g of sodium lauryl sulfate in 60 g of deionized water to form a water phase; mix the two phases and stir at room temperature for 10 minutes, and stir well The emulsion was put into an IKA-T25B high-speed pulverizer, stirred at a high speed of 23,000 rpm for 1 minute, and then stirred at a high speed of 16,000 rpm for 5 minutes to form a fine emulsion.

Under nitrogen protection, 1/3 of the miniemulsion, 30 g of deionized water and 0.2 g of initiator ammonium persulfate were added to the glass reactor. Stir and heat up to 74°C. After reacting for 2 hours, within 2 hours, the remaining miniemulsion containing 0.2 g of ammonium persulfate was added dropwise to the reactor at a constant speed within 2 hours. After the dropwise addition, add 0.2 g of ammonium persulfate and keep warm for two hours; after cooling down to 50°C, add ammonia water to adjust the pH value to 8-9, and then discharge.

There is no gel in the emulsion after polymerization, and the emulsion is coated on a glass slide, and after drying in an oven at 40° C. for 24 hours, visual observation finds that the resulting paint film has good transparency. ) to measure the contact angle of the paint film to water, the results are shown in Table 1.

Embodiment 2: Preparation 2 of modified emulsion

Dissolve 2.0 grams of fluororubber in the monomer mixture caused by 20 grams of methyl methacrylate, 20 grams of butyl acrylate and 1.5 grams of acrylic acid, and dissolve 0.2 grams of oil-soluble co-emulsifier hexadecane in the above mixture to form Oil phase; 0.4 grams of octylphenol polyoxyethylene ether and 0.6 grams of sodium lauryl sulfate were dissolved in 60 grams of deionized water to form an aqueous phase; the two phases were mixed and stirred at room temperature for 15 minutes, and the stirring The emulsion was put into an IKA-T25B high-speed pulverizer, stirred at a high speed of 23,000 rpm for 1 minute, and then stirred at a high speed of 16,000 rpm for 5 minutes to form a fine emulsion.

Under nitrogen protection, 1/3 of the miniemulsion, 30 g of deionized water and 0.2 g of initiator ammonium persulfate were added to the glass reactor. Stir and heat up to 76° C. After reacting for 2 hours, within 2 hours, the remaining miniemulsion containing 0.2 g of ammonium persulfate was added dropwise to the reactor at a constant speed within 2 hours. After the dropwise addition, add 0.2 g of ammonium persulfate and keep warm for two hours; after cooling down to 50°C, add ammonia water to adjust the pH value to 8-9, and then discharge.

There is no gel in the polymerized emulsion, and the emulsion is coated on a glass slide, and after drying in an oven at 40°C for 24 hours, visual observation shows that the obtained paint film has good transparency, and the contact angle of the paint film to water is measured, and the results are shown in Table 1.

Embodiment 3: Preparation 3 of modified emulsion

Dissolve 3.0 grams of fluororubber in the monomer mixture caused by 20 grams of methyl methacrylate, 20 grams of butyl acrylate and 1.5 grams of acrylic acid, and dissolve 0.2 grams of oil-soluble co-emulsifier hexadecane in the above mixture to form Oil phase; 0.6 grams of octylphenol polyoxyethylene ether and 0.4 grams of sodium lauryl sulfate were dissolved in 60 grams of deionized water to form an aqueous phase; the two phases were mixed and stirred at room temperature for 20 minutes, and the mixture was well stirred The emulsion was put into an IKA-T25B high-speed pulverizer, stirred at a high speed of 23,000 rpm for 1 minute, and then stirred at a high speed of 16,000 rpm for 5 minutes to form a fine emulsion.

Under nitrogen protection, 1/3 of the miniemulsion, 30 g of deionized water and 0.2 g of initiator ammonium persulfate were added to the glass reactor. Stir and heat up to 80° C. After reacting for 2 hours, within 2 hours, the remaining miniemulsion containing 0.2 g of ammonium persulfate was added dropwise to the reactor at a constant speed within 2 hours. After the dropwise addition, add 0.2 g of ammonium persulfate and keep it warm for 2.5 hours; after cooling down to 45°C, add ammonia water to adjust the pH value to 8-9, and discharge.

There is no gel in the polymerized emulsion, and the emulsion is coated on a glass slide, and after drying in an oven at 40°C for 24 hours, visual observation shows that the obtained paint film has good transparency, and the contact angle of the paint film to water is measured, and the results are shown in Table 1.

Embodiment 4: Preparation 4 of modified emulsion

Dissolve 4.0 grams of fluororubber in the monomer mixture caused by 20 grams of methyl methacrylate, 20 grams of butyl acrylate and 1.5 grams of acrylic acid, and dissolve 0.2 grams of oil-soluble co-emulsifier hexadecane in the above mixture to form Oil phase; dissolve 0.5 g of octylphenol polyoxyethylene ether and 0.5 g of sodium lauryl sulfate in 60 g of deionized water to form a water phase; mix the two phases and stir at room temperature for 10 minutes, and stir well The emulsion was put into an IKA-T25B high-speed pulverizer, stirred at a high speed of 23,000 rpm for 1 minute, and then stirred at a high speed of 16,000 rpm for 5 minutes to form a fine emulsion.

Under nitrogen protection, 1/3 of the miniemulsion, 30 g of deionized water and 0.2 g of initiator ammonium persulfate were added to the glass reactor. Stir and heat up to 78° C. After reacting for 2 hours, within 2.5 hours, the remaining miniemulsion containing 0.2 g of ammonium persulfate was added dropwise to the reactor at a constant speed within 2.5 hours. After the dropwise addition, add 0.2 g of ammonium persulfate and keep warm for two hours; after cooling down to 50°C, add ammonia water to adjust the pH value to 8-9, and then discharge.

The polymerized emulsion contained 0.38% gel (by weight, based on the total weight of the emulsion composition). The emulsion was coated on a glass slide, and after drying in an oven at 40°C for 24 hours, it was found by visual observation that the resulting paint film had good transparency. The contact angle of the paint film to water was measured, and the results are shown in Table 1.

Embodiment 5: Preparation 5 of modified emulsion

Dissolve 5.0 grams of fluororubber in the monomer mixture caused by 20 grams of methyl methacrylate, 20 grams of butyl acrylate and 1.5 grams of acrylic acid, and dissolve 0.2 grams of oil-soluble co-emulsifier hexadecane in the above mixture to form Oil phase; 0.5 g of octylphenol polyoxyethylene ether and 0.5 g of sodium lauryl sulfate were dissolved in 60 g of deionized water to form a water phase; the two phases were mixed and stirred at room temperature for 20 minutes, and the stirred The emulsion was put into an IKA-T25B high-speed pulverizer, stirred at a high speed of 23,000 rpm for 1 minute, and then stirred at a high speed of 16,000 rpm for 5 minutes to form a fine emulsion.

Under nitrogen protection, 1/3 of the miniemulsion, 30 g of deionized water and 0.2 g of initiator ammonium persulfate were added to the glass reactor. Stir and heat up to 72°C. After reacting for 2 hours, within 1.5 hours, the remaining miniemulsion containing 0.2 g of ammonium persulfate was added dropwise to the reactor at a constant speed within 1.5 hours. After the dropwise addition, add 0.2 g of ammonium persulfate and keep warm for two hours; after cooling down to 50°C, add ammonia water to adjust the pH value to 8-9, and then discharge.

There is 0.76% gel (weight, based on the total weight of the emulsion composition) in the polymerized emulsion, indicating that with the increase of the added amount of fluororubber, the system begins to become unstable. The emulsion was coated on a glass slide, and after drying in an oven at 40°C for 24 hours, it was found by visual observation that the resulting paint film had good transparency. The contact angle of the paint film to water was measured, and the results are shown in Table 1.

Embodiment 6: Preparation 6 of modified emulsion

Dissolve 6.0 grams of fluorine rubber in a monomer mixture composed of 20 grams of methyl methacrylate, 20 grams of butyl acrylate and 1.5 grams of acrylic acid, and dissolve 0.2 grams of oil-soluble co-emulsifier hexadecane in the above mixture to form Oil phase; 0.5 g of octylphenol polyoxyethylene ether and 0.5 g of sodium lauryl sulfate were dissolved in 60 g of deionized water to form a water phase; the two phases were mixed and stirred at room temperature for 20 minutes, and the stirred The emulsion was put into an IKA-T25B high-speed pulverizer, stirred at a high speed of 23,000 rpm for 1 minute, and then stirred at a high speed of 16,000 rpm for 5 minutes to form a fine emulsion.

Under nitrogen protection, 1/3 of the miniemulsion, 30 g of deionized water and 0.2 g of initiator ammonium persulfate were added to the glass reactor. Stir and heat up to 72°C. After reacting for 2 hours, within 1.5 hours, the remaining miniemulsion containing 0.2 g of ammonium persulfate was added dropwise to the reactor at a constant speed within 1.5 hours. After the dropwise addition, add 0.2 g of ammonium persulfate and keep warm for two hours; after cooling down to 50°C, add ammonia water to adjust the pH value to 8-9, and then discharge.

There is 0.69% gel (weight, based on the total weight of the emulsion composition) in the polymerized emulsion, indicating that the system is further unstable with the further increase of the added amount of the fluororubber. The emulsion was coated on a glass slide, and after drying in an oven at 40°C for 24 hours, it was found by visual observation that the resulting paint film had good transparency. The contact angle of the paint film to water was measured, and the results are shown in Table 1.

Comparative Example: Preparation of Unmodified Emulsion

Dissolve 0.5 g of octylphenol ethoxylate and 0.5 g of sodium lauryl sulfate in 60 g of deionized water, and dissolve 0.2 g of oil-soluble co-emulsifier hexadecane in 20 g of methyl methacrylate , 20 grams of butyl acrylate and 1.5 grams of acrylic acid monomer mixture. After the two phases are mixed, stir at room temperature for 10 minutes, put the stirred emulsion into the IKA-T25B high-speed pulverizer, stir at a speed of 23,000 rpm for 1 minute, and then stir at a speed of 16,000 rpm for 5 minutes , then the system is a miniemulsion.

Under nitrogen protection, 1/3 of the miniemulsion, 30 g of deionized water and 0.2 g of initiator ammonium persulfate were added to the glass reactor. The stirring speed was 270 rpm, and the temperature was raised to 74°C. After reacting for 2 hours, the remaining miniemulsion (containing 0.2 g of initiator ammonium persulfate) was added dropwise to the reactor from a constant pressure funnel within 2 hours. After the dropwise addition, add 0.2 g of initiator ammonium persulfate and keep warm for two hours; after cooling down to 50°C, add ammonia water to adjust the pH value to alkaline, and then discharge. The emulsion was coated on a glass slide, and after drying in an oven at 40°C for 24 hours, it was found by visual observation that the resulting paint film had good transparency. The contact angle of the paint film to water was measured, and the results are shown in Table 1.

It can be seen from the above examples that when the amount of fluororubber added is less than 3.0 g, there will be no gel in the emulsion and the system will have good stability.

Table 1 The contact angle of different emulsion paint films to water project comparative example Example 1 2 3 4 5 6 Contact angle/° 59.85 73.86 77.23 81.59 76.44 75.76 73.91

It can be clearly seen from Table 1 that the contact angle of the fluorine rubber modified polyacrylate emulsion paint film is much higher than that of the unmodified emulsion paint film, indicating that the hydrophobicity of the paint film surface has been greatly improved. In addition, the prepared emulsion has good stability and can be stored for a long time. The fluororubber modified polyacrylate emulsion of the invention can be applied to the finishing of building materials, fabrics and the like.

Claims (1)

1, a kind of preparation method of the polyacrylate emulsion of fluorine rubber modification, it is characterized in that the method comprises the following steps: (1) Prepare a monomer mixture composed of methyl methacrylate, butyl acrylate and acrylic acid, the ratio of which is 1:1:0.05-0.1, and then dissolve the fluororubber in the above-mentioned In the mixture of monomers, according to the ratio of 1:200~250, dissolve the co-emulsifier in the above mixture to form the oil phase for later use; according to the ratio of 1:50~70, dissolve the nonionic emulsifier and anionic emulsifier In water, form an aqueous phase, wherein the ratio of the non-ionic emulsifier to the anionic emulsifier is 1:0.5-2, then mix the oil phase and the water phase, and stir at room temperature for 5-20 minutes; (2) Using a high-speed mixer to stir the above-mentioned mixture at a high speed to become a fine emulsion; (3) Add initiator in the miniemulsion, wherein the ratio of the amount of initiator added to the total fluororubber is 1: 5-30; (4) Under the protection of nitrogen, add the above-mentioned second step miniemulsion, deionized water and initiator in the container, wherein, the ratio of fluororubber total amount and miniemulsion is 1: 4-60, fluororubber total amount and The ratio of deionized water is 1:4-40, the ratio of the total amount of fluororubber to the initiator is 4-40:1, stir and heat up to 60-90°C, after 1-3 hours of reaction, after 1-3 hours Inside, add the miniemulsion of the above third step into the container at a constant speed from the constant pressure funnel, the ratio of the total amount of fluororubber to the miniemulsion is 1: 4-60, after the addition is completed, add the initiator, and its consumption is 1/5-1/30 of the total amount of fluororubber, after 1-3 hours of heat preservation, add ammonia water to adjust the pH value to 7.5-9.5, which is the fluororubber modified polyacrylate emulsion.