CN104356935B - Waterborne organic silicon coating and preparation method thereof - Google Patents

Abstract

The invention discloses a water-based organic silicon coating. The components and weight percentages of the water-based organic silicon coating are: 2.00-40.00% of organic silicon emulsion, 12.00-40.00% of nano-silica sol, 0.50-5.00% of dispersant, wetting 0.10-1.50% of additives, 1.00-45.00% of fillers, 10.00-25.00% of pigments, 0.30-5.00% of thickeners, 0.00-1.50% of leveling agents, 0.30-3.00% of film-forming aids, 0.08-0.20% of fungicides and 0.00-0.50 defoaming agent; the balance is deionized water; wherein, the solid content of the organic silicon emulsion is 50%, and the nano-silica sol is epoxy silane modified silica sol. The invention also discloses a preparation method of the water-based organic silicon coating. The water-based organic silicon paint has low cost and good environmental protection performance, and its paint film has excellent adhesion and strength, and excellent heat resistance up to 750°C.

Description

Water-based organosilicon coating and preparation method thereof

technical field

The invention relates to the field of coatings, in particular to a water-based silicone coating and a preparation method thereof.

Background technique

Existing solvent-based silicone coatings include silicone resin liquid, fillers, pigments, additives, and organic solvents. The film-forming substance is silicone resin, and the film-forming substance is single. Due to the high content of the silicone resin liquid, the coating cost High; and due to the presence of organic solvents in solvent-based silicone coatings, the VOC content is high, toxic, pungent odor, poor environmental performance, flammable and explosive, and poor safety. In addition, the film formation of silicone coatings requires heating and baking, which wastes energy, and the heat resistance of the paint film is poor, and the performance of the paint film needs to be improved urgently.

Contents of the invention

The main purpose of the present invention is to provide a water-based organic silicon coating, aiming to solve the technical problems of the existing organic silicon coatings such as high cost, high VOC content, poor safety and environmental protection performance, need to be heated to form a film and poor heat resistance.

In order to achieve the above object, the invention provides a kind of water-based organic silicon coating, and the component of described water-based organic silicon coating and weight percentage thereof are:

Silicone emulsion 2.00-40.00%, nano-silica sol 12.00-40.00%, dispersant 0.50-5.00%, wetting agent 0.10-1.50%, filler 1.00-45.00%, pigment 10.00-25.00%, thickener 0.30-5.00% , leveling agent 0.00-1.50%, film-forming aid 0.30-3.00%, bactericide 0.08-0.20%, and defoamer 0.00-0.50; the balance is deionized water;

Wherein, the solid content of the silicone emulsion is 50%, and the nano silica sol is epoxy silane modified silica sol.

Preferably, the components of the waterborne silicone coating and their weight percentages are:

Silicone emulsion 25.36%, nano-silica sol 25.36%, dispersant 2.54%, wetting agent 0.85%, filler 18.60%, pigment 16.91%, thickener 2.54%, leveling agent 0.85%, film-forming aid 1.69%, 0.13% bactericide, 0.13% defoamer and 5.07% deionized water.

Preferably, the components of the waterborne silicone coating and their weight percentages are:

Silicone emulsion 30.67%, nano-silica sol 21.91%, dispersant 1.75%, wetting agent 0.70%, filler 17.53%, pigment 17.53%, thickener 1.75%, leveling agent 0.88%, film-forming aid 1.75%, Bactericide 0.13%, defoamer 0.13% and deionized water 5.26%.

Preferably, the components of the waterborne silicone coating and their weight percentages are:

Silicone emulsion 21.15%, nano-silica sol 29.61%, dispersant 2.54%, wetting agent 0.85%, filler 21.15%, pigment 12.69%, thickener 1.69%, leveling agent 0.85%, film-forming aid 2.54%, 0.08% bactericide, 0.08% defoamer and 6.77% deionized water.

Preferably, the filler includes kaolin, sericite powder and silica micropowder.

Preferably, the pigment is rutile titanium dioxide.

Preferably, the film-forming aid is dipropylene glycol butyl ether.

Preferably, the dispersant is potassium polycarboxylate, sodium polycarboxylate, ammonium polycarboxylate, or nonionic polyurethane oligomer.

In addition, in order to achieve the above object, the present invention also provides a preparation method of the above-mentioned water-based silicone coating, the preparation method of the water-based silicone coating comprises the following steps:

Preparation of epoxy silane modified silica sol;

Add silicone latex, dispersant, wetting agent, thickener, defoamer, bactericide and film-forming aid into the container, stir and mix evenly;

Continue to add fillers and pigments to the container, and disperse the solid particle size to ≤35um;

Continue to add epoxy silane modified silica sol to the container, stir and mix evenly;

Continue to add ion-free water and a leveling agent into the container to adjust the viscosity to prepare a water-based silicone coating.

Preferably, the preparation of epoxy silane modified silica sol specifically includes the following steps:

Add silica sol and bioactivator to the jacketed reactor, and stir at 0-90 rpm;

The epoxy silane is added into the jacketed reaction kettle by dropping, and reacted at 25-95° C. for 1-8 hours to prepare the epoxy-silane-modified silica sol.

The water-based organosilicon coating and the preparation method thereof of the present invention add epoxy silane modified silica sol to the organosilicon coating composition, the nano silica sol and the organosilicon latex together form a film-forming substance, which reduces the amount of the organosilicon emulsion, Since the cost of nano-silica sol is only 15-20% of the silicone emulsion, the cost of the coating is reduced. At the same time, the interaction between the nano-silica sol and the silicone latex improves the performance of the water-based silicone coating and further improves the adhesion of the paint film. Concentration, heat resistance and strength, so that the paint film of the water-based silicone coating has strong adhesion, good impact strength, good heat resistance, heat resistance up to 750°C and the film-forming performance of the water-based silicone coating is good, no need Heating and baking saves energy. In addition, since the film-forming of silica sol does not require film-forming aids, the amount of film-forming aids is reduced, so the VOC content of the water-based silicone coating is greatly reduced, which is conducive to environmental protection and has good safety and environmental protection performance.

detailed description

It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The invention provides a kind of water-based organic silicon coating, and the component of described water-based organic silicon coating and weight percentage thereof are:

Silicone emulsion 2.00-40.00%, nano-silica sol 12.00-40.00%, dispersant 0.50-5.00%, wetting agent 0.10-1.50%, filler 1.00-45.00%, pigment 10.00-25.00%, thickener 0.30-5.00% , leveling agent 0.00-1.50%, film-forming aid 0.30-3.00%, bactericide 0.08-0.20%, and defoamer 0.00-0.50; the balance is deionized water; among them, the solid content of silicone emulsion is 50% , Nano silica sol is epoxy silane modified silica sol.

The water-based organosilicon coating of the present invention forms a film-forming substance together with the organosilicon emulsion by adding epoxy-based silane-modified silica sol, and the modified group of the epoxy-based silane-modified silica sol and the molecular chain of the organosilicon emulsion form a physical The entangled and interpenetrating network, compared with the existing silicone coating, greatly improves the adhesion, strength, heat resistance and weather resistance of the paint film of the water-based silicone coating of the present invention, and its heat resistance is as high as 750 °C; in addition , because the cost of silica sol is far lower than the cost of silicone emulsion, therefore, the cost of water-based silicone coating of the present invention reduces; Since the film-forming of epoxy-based silane-modified silica sol does not need film-forming aids, it satisfies various Under the premise of the performance requirements of the paint film, the greater the proportion of epoxy silane modified silica sol, the lower the VOC content of the paint, the more economical the cost, the better the performance of the paint film, which is conducive to environmental protection, good safety and environmental protection performance and this Invented water-based silicone coatings are self-drying and film-forming, without heating and baking, easy to use, and energy-saving.

In a preferred embodiment, the silicone emulsion is MP-50E silicone emulsion.

In a preferred embodiment, the dispersant is polycarboxylate potassium salt, polycarboxylate sodium salt, polycarboxylate ammonium salt or nonionic polyurethane oligomer, and the dispersant is used for dispersing, suspending and stabilizing the organic silicon coating Pigments and fillers to improve the stability of coating systems.

In a preferred embodiment, the wetting agent is a nonionic wetting agent or an anionic wetting agent. Nonionic wetting agent is alkyl polyoxyethylene ether, polyoxyethylene alkylphenol ether, or polyoxyethylene fatty alcohol ether; anionic wetting agent is alkyl sulfate, alkyl sulfonate, fatty acid or phosphoric acid ester. Wetting agents are used for wetting, dispersing, anti-sedimentation and wetting of substrates for pigments and fillers in the coating system to increase the adhesion of the coating.

In a preferred embodiment, the filler includes kaolin, sericite powder and silica micropowder. The filler is silicate, and the nano-silica sol has better adhesion to it, so that the paint film of the water-based silicone paint has better weather resistance and strength.

In a preferred embodiment, the pigment is rutile titanium dioxide, composite inorganic pigment or water-based aluminum silver paste. Preferably, the pigment is rutile titanium dioxide.

In a preferred embodiment, the thickener is hydroxyethyl cellulose, hydroxypropyl cellulose, polyurethane thickener, or acrylic alkali swelling thickener. Thickeners are used to increase the viscosity of waterborne silicone coatings and improve the rheology of the coatings.

In a preferred embodiment, the leveling agent is polyurethane polyether or polyether polydimethylsiloxane. The leveling agent is used to improve the rheological properties of the coating, to improve the stability and coating performance of the coating, and to improve the quality of the coating film. Such as: prevent the precipitation of pigments and fillers during paint storage, avoid splashing and sagging of paint during painting, improve the leveling performance of the paint film, etc.

In a preferred embodiment, the film-forming aid is dipropylene glycol dimethyl ether (DPDM), dipropylene glycol methyl ether (DPM), dipropylene glycol butyl ether (DPNB) or diethylene glycol butyl ether acetate. Preferably, the coalescent is dipropylene glycol butyl ether. Due to the addition of silica sol, the amount of silicone emulsion is reduced, and the film formation of silica sol does not require a film-forming agent, which greatly reduces the use of film-forming aids, reduces VOC content, and further improves the environmental protection of water-based silicone coatings. sex.

In a preferred embodiment, the antifoaming agent is a mixture of silicone and mineral oil, a fatty acid salt or a derivative of silicone. Defoamers are used to remove harmful foams generated during the coating production process.

In a preferred embodiment, the fungicide is isothiazolinone or benzisothiazolinone, which can improve the anti-mold effect of the waterborne silicone coating, and further improve the stability of the waterborne silicone coating.

In a preferred embodiment, the composition and weight percentage of epoxy silane modified silica sol are:

Silica sol 68.00-98.00%, epoxy silane 0.50-21.00%, and bioactivator 0.00-0.35%. Wherein, the preparation method of epoxy silane modified silica sol is as follows:

Provide a jacketed reactor, add silica sol and bioactivator to the jacketed reactor, the jacketed reactor adopts frame stirring, and the speed is 0-90 rpm;

The epoxy silane is added dropwise into the jacketed reactor, the reaction temperature is 25-95° C., and the reaction time is 1-8 hours, and the epoxy silane-modified silica sol can be prepared.

Wherein, silica sol is acidic silica sol, alkaline silica sol, or neutral silica sol; Epoxy silane is preferably 3 ~ glycidyl ether methyl propyl trimethoxy silane, vinyl triethoxy silane, 3 ~ Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, or methyltrimethoxysilane.

The present invention also provides a kind of preparation method of waterborne organosilicon coating, comprises the steps:

Preparation of epoxy silane modified silica sol;

Add silicone latex, dispersant, wetting agent, thickener, defoamer, bactericide and film-forming aid into the container, stir and mix evenly; in a preferred embodiment, the container is a paint can;

Continue to add fillers and pigments to the container, and disperse the solid particle size to ≤35um; in a preferred embodiment, adding fillers and pigments is carried out under stirring, which is conducive to uniform dispersion of fillers and pigments, and high-speed dispersion The particle size of final solid particles is less than or equal to 35um;

Continue to add epoxy silane modified silica sol to the container, stir and mix evenly; in a preferred embodiment, adding epoxy silane modified silica sol is carried out under stirring;

Continue to add ion-free water and a leveling agent into the container to adjust the viscosity to prepare a water-based silicone coating.

In the preparation method of this waterborne organosilicon coating, the preparation method of epoxy silane modified silica sol is as follows:

Provide a jacketed reactor, add silica sol and bioactivator to the jacketed reactor, the jacketed reactor adopts frame stirring, and the speed is 0-90 rpm;

The epoxy silane is added dropwise into the jacketed reactor, the reaction temperature is 25-95° C., and the reaction time is 1-8 hours, and the epoxy silane-modified silica sol can be prepared.

Wherein, silica sol is acidic silica sol, alkaline silica sol, or neutral silica sol; Epoxy silane is preferably 3 ~ glycidyl ether methyl propyl trimethoxy silane, vinyl triethoxy silane, 3 ~ Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, or methyltrimethoxysilane.

Water-based organosilicon coating of the present invention and preparation method thereof are further described by the following examples:

Example 1

MP-50E silicone emulsion 30Kg, polycarboxylate potassium salt 3Kg, alkyl polyoxyethylene ether 1Kg, hydroxyethyl cellulose 3Kg, fatty acid salt 0.15Kg, isothiazolinone 0.15Kg, and dipropylene glycol butyl ether 2Kg Add the paint pot, stir and mix evenly; then, under stirring, sequentially add kaolin 7Kg, sericite powder 5Kg, silicon micropowder 10Kg and rutile titanium dioxide 20Kg, and disperse at a high speed until the particle size of the solid particles is ≤35um; then, while stirring Next, add 30Kg of epoxy silane-modified silica sol and mix evenly; finally, add 6Kg of deionized water and 1Kg of polyurethane polyether to adjust the viscosity to prepare a water-based silicone coating.

Example 2:

MP-50E silicone emulsion 35Kg, polycarboxylate potassium salt 2Kg, alkyl polyoxyethylene ether 0.8Kg, hydroxyethyl cellulose 2Kg, fatty acid salt 0.15Kg, isothiazolinone 0.15Kg, and dipropylene glycol butyl ether 2Kg, add it to the paint pot, stir and mix evenly; then, under stirring, add 7Kg of kaolin, 5Kg of sericite, 8Kg of silicon micropowder and 20Kg of rutile titanium dioxide in sequence, and disperse at a high speed until the particle size of the solid particles is ≤35um; then, Under stirring, add 25Kg of epoxy silane-modified silica sol and mix evenly; finally, add 6Kg of deionized water and 1Kg of polyurethane polyether to adjust the viscosity to prepare a water-based silicone coating.

Example 3

Mix MP-50E silicone emulsion 25Kg, polycarboxylate potassium salt 3Kg, alkyl polyoxyethylene ether 1Kg, hydroxyethyl cellulose 2Kg, fatty acid salt 0.1Kg, isothiazolinone 0.1Kg, and dipropylene glycol butyl ether 3Kg , add to the paint pot, stir and mix evenly; then, under stirring, sequentially add 10Kg of kaolin, 10Kg of sericite, 5Kg of silicon micropowder and 15Kg of rutile titanium dioxide, and disperse at a high speed until the particle size of the solid particles is ≤35um; then, while stirring Next, add 35Kg of epoxy silane-modified silica sol and mix evenly; finally, add 8Kg of deionized water and 1Kg of polyurethane polyether to adjust the viscosity to prepare a water-based silicone coating.

Performance parameters such as adhesion, impact strength and heat resistance of the paint film of the water-based silicone coating prepared by the above-described embodiments are shown in Table 1 below:

Table 1

Example 1 Example 2 Example 3 Adhesion Level 1 Level 1 Level 1 Impact strength (Kj/m ² ) 50 50 50 Heat resistance (℃) 750°C 750°C 750°C

Among them, the heat resistance test standard of the paint film is in accordance with GB1735-79, GB1732-79; the test standard of the impact strength of the paint film is in accordance with GB1732-79; the test standard of paint film adhesion is in accordance with GB/T9286.

It can be seen from the above that the paint film of the water-based silicone coating of the present invention has excellent adhesion and impact strength, and has excellent heat resistance, reaching 750°C.

The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the description of the present invention, or directly or indirectly used in other related technical fields, shall be the same as The theory is included in the patent protection scope of the present invention.

Claims (10)

1. a waterborne organic silicon coating, it is characterised in that component and the percentage by weight thereof of described waterborne organic silicon coating be:

Organic silicon emulsion 2.00～40.00%, Nano silica sol 12.00～40.00%, dispersant 0.50～5.00%, wetting agent 0.10～1.50%, filler 1.00～45.00%, pigment 10.00～25.00%, thickening agent 0.30～5.00%, levelling agent 0.00～1.50%, coalescents 0.30～3.00%, antibacterial 0.08～0.20% and defoamer 0.00～0.50；Surplus is deionized water；

Wherein, the solids content of described organic silicon emulsion is 50%, and described Nano silica sol is epoxy radicals silicone hydride modified silicasol.

2. waterborne organic silicon coating as claimed in claim 1, it is characterised in that component and the percentage by weight thereof of described waterborne organic silicon coating be:

The mixture 18.60% of organic silicon emulsion 25.36%, epoxy radicals silicone hydride modified silicasol 25.36%, polycarboxylic acids potassium salt 2.54%, alkyl polyoxyethylene ether 0.84%, Kaolin, sericite in powder and silicon powder, Rutile type titanium dioxide 16.90%, hydroxyethyl cellulose 2.54%, polyurethane polyethers 0.84%, dipropylene 1.69%, isothiazolone 0.13%, soap 0.13% and deionized water 5.07%.

3. waterborne organic silicon coating as claimed in claim 1, it is characterised in that component and the percentage by weight thereof of described waterborne organic silicon coating be:

The mixture 17.53% of organic silicon emulsion 30.68%, epoxy radicals silicone hydride modified silicasol 21.91%, polycarboxylic acids potassium salt 1.75%, alkyl polyoxyethylene ether 0.70%, Kaolin, sericite in powder and silicon powder, Rutile type titanium dioxide 17.53%, hydroxyethyl cellulose 1.75%, polyurethane polyethers 0.88%, dipropylene 1.75%, isothiazolone 0.13%, soap 0.13% and deionized water 5.26%.

4. waterborne organic silicon coating as claimed in claim 1, it is characterised in that component and the percentage by weight thereof of described waterborne organic silicon coating be:

Organic silicon emulsion 21.15%, Nano silica sol 29.61%, dispersant 2.54%, wetting agent 0.85%, filler 21.15%, pigment 12.69%, thickening agent 1.69%, levelling agent 0.85%, coalescents 2.54%, antibacterial 0.08%, defoamer 0.08% and deionized water 6.77%.

5. the waterborne organic silicon coating as described in claim 1 or 4, it is characterised in that described filler includes Kaolin, sericite in powder and silicon powder.

6. the waterborne organic silicon coating as described in claim 1 or 4, it is characterised in that described pigment is Rutile type titanium dioxide.

7. the waterborne organic silicon coating as described in claim 1 or 4, it is characterised in that described coalescents is dipropylene.

8. the waterborne organic silicon coating as described in claim 1 or 4, it is characterised in that described dispersant is polycarboxylic acids potassium salt, polycarboxylate sodium, polycarboxylic acids ammonium salt or non-ionic polyurethane oligomer.

9. the preparation method of the waterborne organic silicon coating as described in claim 1 to 8 any one, it is characterised in that the preparation method of described waterborne organic silicon coating comprises the steps:

Prepare epoxy radicals silicone hydride modified silicasol；

Organosilicon latex, dispersant, wetting agent, thickening agent, defoamer, antibacterial and coalescents are added in container, is uniformly mixed；

Continue to add filler and pigment in described container, and dispersing solid particle diameter is to≤35um；

Continue to add epoxy radicals silicone hydride modified silicasol in described container, be uniformly mixed；

Continue to add deionized water and levelling agent in described container, adjust viscosity, prepare waterborne organic silicon coating.

10. the preparation method of waterborne organic silicon coating as claimed in claim 9, it is characterised in that described epoxy radicals silicone hydride modified silicasol of preparing specifically includes following steps:

In jacket reactor, add Ludox and bio-activator, and be stirred under 0～90 rev/min of rotating speed；

Adopt dropping mode to add in jacket reactor by epoxy radicals silicone hydride, react 1～8 hour at 25～95 DEG C, prepare epoxy radicals silicone hydride modified silicasol.