CN105017871B - A kind of antiultraviolet exterior coating and preparation method thereof - Google Patents

Abstract

The invention discloses an anti-ultraviolet exterior wall paint and a preparation method thereof. The preparation method first coats a layer of acrylate polymer on the surface of nano-titanium dioxide to obtain nano-titanium dioxide/acrylate polymer composite emulsion, then fully mixes the composite emulsion with acrylate polymer exterior wall emulsion, and then adds pigments, fillers and additives and water. The coating coats a layer of acrylate polymer on the surface of nano-titanium dioxide, which significantly improves the dispersion and stability of nano-titanium dioxide in the coating, avoids the formation of nano-titanium dioxide aggregates, and the UV protection performance of the aggregates will be greatly reduced or even absent. The paint not only has the characteristics of excellent water resistance, alkali resistance and scrub resistance of acrylate polymer exterior wall paint, but also improves its hardness and anti-ultraviolet performance, prolongs the service life of the paint, and has a simple preparation method and low production cost. Low, conducive to industrial production.

Description

A kind of anti-ultraviolet exterior wall paint and preparation method thereof

technical field

The invention relates to an exterior wall coating, in particular to an anti-ultraviolet exterior wall coating and a preparation method thereof; it belongs to the technical field of material synthesis and coating preparation technology.

Background technique

Light, heat, water, oxygen, inorganic salts, organic solvents and pollutants in the environment are the main factors that promote the degradation of film-forming substances. Among these factors, solar ultraviolet radiation is the most important and most common factor leading to the degradation of film-forming substances. From the moment the exterior wall paint is used, it begins its irreversible degradation process. Therefore, it is necessary to enhance the anti-ultraviolet performance of exterior wall coatings. The simplest and most effective method is to add additives with anti-ultraviolet properties to exterior wall coatings, mainly organic ultraviolet shielding agents and inorganic ultraviolet shielding agents.

Currently widely used organic UV shielding includes o-hydroxybenzophenone, o-hydroxybenzotriazole, o-hydroxybenzotriazine, salicylate, benzoate, cinnamate and oxalanilide, etc., but adding organic There are many disadvantages of UV shielding agents to improve the UV protection performance of coatings. Firstly, the organic UV screener has certain toxicity; secondly, the organic UV screener has selective absorption of ultraviolet rays; finally, as time goes on, the UV protection performance of the organic UV screener will gradually weaken or even disappear.

Inorganic UV shielding agents mainly include nano-titanium dioxide, nano-silicon dioxide and nano-zinc oxide. Nano-titanium dioxide has attracted much attention because of its stable chemical properties, non-toxicity, low price and strong ultraviolet shielding performance.

Nano-titanium dioxide has strong ultraviolet shielding performance, and the smaller the particle size, the stronger the ultraviolet shielding performance. Submicron titanium dioxide hardly shields ultraviolet rays. The ultraviolet shielding performance of nano titanium dioxide is determined by its absorption ability and scattering ability. The absorption of nano-titanium dioxide to ultraviolet light is mainly due to its semiconducting properties. Under the irradiation of ultraviolet rays, electrons are excited and then transition from the valence band to the conduction band, which causes the absorption of ultraviolet rays. Nano-titanium dioxide not only has the ability to absorb ultraviolet rays, but also has the ability to scatter ultraviolet rays. Ultraviolet rays are essentially an electromagnetic wave. When ultraviolet rays act on nano-titanium dioxide in the medium, because the size of nano-titanium dioxide particles is smaller than the wavelength of ultraviolet rays, the electrons in nano-titanium dioxide particles are forced to vibrate (the vibration frequency is the same as the frequency of the incident light wave), It becomes a secondary wave source and emits electromagnetic waves in all directions, which is the scattering of ultraviolet rays.

At present, there have been examples of using nano-titanium dioxide in anti-ultraviolet exterior wall coatings. Chinese invention patent application CN102604498A adds rutile nano-titanium dioxide to the water-based exterior wall latex paint to improve the UV protection performance of the exterior wall latex paint. The particle size of the rutile nano-titanium dioxide used is 20nm, and the specific surface area is large. It is very easy to agglomerate in the material, and the agglomerates will greatly reduce the anti-ultraviolet performance of rutile nano-titanium dioxide. Moreover, the compatibility between rutile nano-titanium dioxide and polymers is poor, gaps will be generated at the interface, and air will enter. Under the irradiation of ultraviolet light, the photocatalysis of rutile nano-titanium dioxide will degrade the surrounding polymers.

Chinese invention patent application CN102134424A first prepares composite powder of Mg-Al hydrotalcite and nano-titanium dioxide, and then disperses it in styrene-acrylic exterior wall paint, and the obtained paint has a certain anti-ultraviolet performance. Although the combination of hydrotalcite and nano-titanium dioxide will enhance the anti-ultraviolet performance of nano-titanium dioxide, the compatibility problem between nano-titanium dioxide and polymers remains unsolved. The dispersibility and stability of nanoparticles in coatings are the key issues to be solved by nano coatings.

Contents of the invention

The object of the present invention is to provide an exterior wall coating with excellent UV protection performance, excellent hardness and scrub resistance of the paint film, aiming at the above-mentioned deficiencies of the anti-ultraviolet exterior wall coating.

The purpose of the present invention is also to provide a preparation method of an anti-ultraviolet exterior wall coating with low production cost, simple process and easy industrial production.

To achieve the above object, the present invention is achieved through the following technical solutions:

A kind of anti-ultraviolet exterior wall paint, its raw material comprises the following components in parts by mass:

Acrylate polymer emulsion 25～40

Nano titanium dioxide/acrylate polymer composite emulsion 5～15

Pigment and filler 15～25

Antifreeze 1.2～1.5

Wetting agent 0.1～0.2

Coalescing agent 1.2～1.8

Dispersant 0.3～0.6

Defoamer 0.1～0.4

Thickener 0.1～0.4

Preservative 0.1～0.3

pH adjuster 0.1～0.2

Deionized water 20～40

The acrylate polymer emulsion is styrene-acrylic emulsion, pure acrylic emulsion, ethylene-acrylic emulsion, tert-acrylic emulsion or silicon-acrylic emulsion with a solid content of 40%;

The nano-titanium dioxide/acrylate polymer composite latex latex particles take nano-titanium dioxide as the core and acrylate polymer as the core-shell structure of the shell, and are prepared according to the following steps:

(1) Preparation of modified nano titanium dioxide

In terms of parts by mass, mix 0.25-5 parts of nano-titanium dioxide with 20-200 parts of solvent, then ultrasonically disperse, add 0.1-5 parts of silane coupling agent, react at 60-80°C for 1-6 hours, centrifuge, and wash with absolute ethanol , centrifuged, washed, and dried to obtain modified nano-titanium dioxide; the solvent is methanol, ethanol, isopropanol or acetone; the silane coupling agent is γ-methacryloxypropyltrimethoxy One of silane, vinyltrimethoxysilane or vinyltriethoxysilane;

(2) Preparation of Nano Titanium Dioxide/Acrylic Ester Polymer Composite Emulsion

In terms of parts by mass, disperse 0.25-5 parts of modified nano-titanium dioxide in a mixture of 20-50 parts of acrylate monomer and 0.5-2 parts of co-emulsifier, ultrasonically disperse it, add it to the aqueous emulsifier solution, and emulsify The amount of the agent is 0.5-2 parts, the amount of deionized water is 40-80 parts, stir, ultrasonically disperse, heat up to 60-80°C, add 0.25-5 parts of initiator, keep warm for 2-6 hours, and obtain nano-titanium dioxide/acrylic acid Ester polymer composite emulsion; the acrylate monomer is methyl methacrylate, tert-butyl methacrylate, acrylamide, butyl acrylate, 2-ethyl acrylate, hydroxyethyl acrylate, methacrylic acid and one or more of acrylic acid; the co-emulsifier is hexadecane, cetyl alcohol, n-pentanol or cyclohexanol; the emulsifier is sodium oleate, sodium lauryl sulfate, Sodium dodecylbenzenesulfonate, Tween 80, Tween 20, Alkylphenol Ethoxylate-10 sorbitan monostearate, polyoxyethylene sorbitan trioleate and polyoxyethylene sorbitan trioleate One or more of ethylene sorbitan monostearate; the initiator is one of hydrogen peroxide, potassium persulfate, ammonium persulfate or potassium persulfate-sodium bisulfite.

Preferably, the pigments and fillers are one or more of titanium dioxide, heavy calcium powder, talcum powder, barium sulfate, mica powder and kaolin; the antifreeze is ethylene glycol or propylene glycol; The wet agent is PE-100, ethanol, propylene glycol or glycerin.

Preferably, the ultrasonic dispersion after mixing 0.25-5 parts of nano-titanium dioxide with 20-200 parts of solvent is ultrasonic dispersion with a power of 400-800W for 5-30 minutes.

Preferably, the drying is at 50-100° C. for 12-24 hours.

Preferably, the ultrasonic dispersion of the nano-titanium dioxide/acrylate polymer composite emulsion is dispersed at an ultrasonic power of 400-800W for 10-60 minutes; the stirring of the nano-titanium dioxide/acrylate polymer composite emulsion is prepared at a speed of Stir for 5-30 minutes at 100-400 rpm.

Preferably, the dispersant is sodium lauryl sulfate, polyoxyethylene alkylphenyl ether, 2-amino-2-methyl-1-propanol, sodium oleate, sodium polyacrylate or polyisobutylene cis Sodium salt of butenedioic acid; coalescent is ethylene glycol, propylene glycol, hexylene glycol, propylene glycol butyl ether, ethylene glycol butyl ether, methyl benzyl alcohol or ethylene glycol butyl ether acetate.

Preferably, the defoamer is butanol, 1,2-propylene glycol, octanol, tributyl phosphate, emulsified dimethyl silicone oil, emulsified benzyl silicone oil, polyoxyethylene polyoxypropylene pentaerythritol ether or polyoxyethylene Ethylene polyoxypropanolamine ether.

Preferably, the thickener is dibutyl phthalate, hydroxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, xanthan gum, XG-60, XG-903, SN-612 or TT-935.

Preferably, the preservative is one of BIT, BIT/MIT, CMIT/MIT or DBNPA; the pH regulator is one of AMP-95, ammonia, sodium hydroxide or potassium hydroxide or Various.

The preparation method of described anti-ultraviolet exterior wall paint, comprises the steps:

(1) preparing nano-titanium dioxide/acrylate polymer composite emulsion;

(2) Prepare the anti-ultraviolet exterior wall coating according to the following steps:

1) Weigh the material according to the formula, add deionized water, wetting agent, dispersant, pH stabilizer and defoamer in sequence under stirring at 500-1500rpm, and stir fully for 10-60min to obtain the prepolymer material;

2) Under stirring at 500-1500rpm, add the formulated amount of pigments and fillers to the pre-polymerized material, mix evenly, and stir at 1000-2000rpm for 30-90min to obtain a dispersion slurry of pigments and fillers;

3) Fully disperse the nano-titanium dioxide/acrylate polymer composite emulsion in the acrylate polymer exterior wall emulsion, slowly add the antifreeze agent into the above mixed emulsion under stirring at 300-600rpm, stir for 10-30min, and mix the obtained mixed solution Add pigment and filler dispersion slurry, then add defoamer and film-forming aid under stirring at 500-1000rpm, and stir for 10-60min;

4) Adjust the pH to 8-9 with a pH regulator, add a thickener, and stir at 500-1000 rpm for 10-60 minutes to obtain an anti-ultraviolet exterior wall coating.

Compared with the prior art, the present invention has the following outstanding effects:

1) In the anti-ultraviolet exterior wall paint of the present invention, a layer of acrylate polymer is coated on the surface of nano-titanium dioxide, which can enhance its compatibility with the polymer, excellent dispersion in the paint, excellent stability, and maintain nanoscale dispersion.

2) Adding nano-titanium dioxide/acrylate polymer composite particles with a core-shell structure to the anti-ultraviolet exterior wall paint of the present invention can not only enhance the anti-ultraviolet performance of the paint, but also enhance the hardness, strength and wear resistance of the paint.

3) In the anti-ultraviolet exterior wall paint of the present invention, the nano-titanium dioxide/acrylate polymer composite particle shell layer adopts the film-forming substance acrylate polymer commonly used in exterior wall paint, which will not affect the scrub resistance of the dry film.

4) The anti-ultraviolet exterior wall paint of the present invention does not contain toxic ultraviolet shielding agents, which is beneficial to environmental protection and construction safety.

Description of drawings

Fig. 1 is the TEM image of the nano-titanium dioxide/acrylate polymer composite emulsion in Example 1.

Fig. 2 is the SEM image of the nano-titanium dioxide/acrylate polymer composite emulsion in Example 1.

Fig. 3 is the SEM-EDS picture of the nano-titanium dioxide/acrylate polymer composite emulsion in Example 1.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments do not constitute a limitation on the protection scope of the present invention.

Example 1

In terms of parts by mass, the formula of the anti-ultraviolet exterior wall paint consists of:

Styrene Acrylic Lotion 25

Nano titanium dioxide/acrylate polymer composite emulsion 5

Titanium dioxide 5

Heavy Calcium Powder 20

Ethylene glycol 1.5

PE100 0.2

Ethylene glycol 1.8

Sodium Lauryl Sulfate 0.6

Butanol 0.4

Dibutyl phthalate 0.1

BIT 0.2

AMP-95 0.1

Ammonia 0.1

Deionized water 40

Prepare UV-resistant exterior paints as follows:

(1) Preparation of Nano Titanium Dioxide/Acrylic Ester Polymer Composite Emulsion

1) Preparation of modified nano titanium dioxide

In terms of parts by mass, mix 5 parts of nano-titanium dioxide with 200 parts of ethanol, 800W ultrasonic dispersion for 35 minutes, add 5 parts of vinyltriethoxysilane, react at 80°C for 6 hours, centrifuge, wash with absolute ethanol, centrifuge and wash Repeat 3 times, and bake at 100° C. for 12 hours to obtain modified nano-titanium dioxide.

2) Preparation of nano-titanium dioxide/acrylate polymer composite emulsion

In terms of parts by mass, 5 parts of modified nano-titanium dioxide were dispersed in a mixed solution of 25 parts of acrylamide, 25 parts of butyl acrylate and 2 parts of cetyl alcohol, ultrasonically dispersed at 400W for 60 minutes, and then added to sodium oleate and Wen 80 aqueous solution, wherein the amount of sodium oleate is 1.3 parts, the amount of Tween 80 is 0.7 parts, the amount of deionized water is 80 parts, 400rpm stirring for 30min, 400W ultrasonic dispersion for 10min, transferred to a four-necked flask, heated to At 60°C, add 0.5 part of ammonium persulfate and keep it warm for 6 hours to obtain a nano-titanium dioxide/acrylate polymer composite emulsion.

(2) Preparation of anti-ultraviolet exterior wall coating

1) Weigh the material according to the formula, add deionized water, PE-100, sodium lauryl sulfate, AMP-95, butanol in sequence under stirring at 1500rpm, and stir thoroughly for 10 minutes to obtain a prepolymer material.

2) Under stirring at 1500rpm, add the formulated amount of titanium dioxide and talc powder to the above prepolymer material, mix well and then stir at a high speed of 2000rpm for 30min to obtain a dispersion slurry of pigments and fillers.

3) Fully disperse the nano-titanium dioxide/acrylate polymer composite emulsion in the styrene-acrylic emulsion, slowly add ethylene glycol into the above-mentioned mixed emulsion under stirring at 600rpm, stir for 10min, add the obtained mixed solution into the pigment and filler dispersion slurry, and then Add butanol and ethylene glycol under stirring at 1000rpm, and stir for 10min.

4) Adjust the pH to 8 with ammonia water, add dibutyl phthalate, and stir at 1000 rpm for 10 minutes to obtain an anti-ultraviolet exterior wall coating.

Example 2

In terms of parts by mass, the formula of the anti-ultraviolet exterior wall paint consists of:

Pure acrylic emulsion 30

Nano titanium dioxide/acrylate polymer composite emulsion 7

Titanium dioxide 6

Mica powder 17

Ethylene glycol 1.5

Ethanol 0.2

Propylene glycol 1.7

Polyoxyethylene alkylphenyl ether 0.5

1,2-Propanediol 0.3

Hydroxymethylcellulose 0.3

BIT/MIT0.3

AMP-95 0.1

Ammonia 0.1

Deionized water 35

Prepare UV-resistant exterior paints as follows:

(1) Preparation of Nano Titanium Dioxide/Acrylic Ester Polymer Composite Emulsion

1) Preparation of modified nano titanium dioxide

In terms of parts by mass, mix 3.2 parts of nano-titanium dioxide with 150 parts of isopropanol, disperse with 400W ultrasonic for 20 minutes, add 1.2 parts of vinyltrimethoxysilane, react at 70°C for 3.5h, centrifuge, wash with absolute ethanol, and centrifuge 1. Washing was repeated 3 times, and the modified nano titanium dioxide was obtained after drying at 50° C. for 24 hours.

2) Preparation of nano-titanium dioxide/acrylate polymer composite emulsion

In terms of parts by mass, 3.2 parts of modified nano-titanium dioxide were dispersed in a mixed solution of 40 parts of methyl methacrylate and 1.8 parts of hexadecane, 500W ultrasonic dispersion was performed for 50 minutes, and sodium lauryl sulfate and Tween 80 In the aqueous solution, the amount of sodium lauryl sulfate is 1.2 parts, the amount of Tween 80 is 0.6 parts, and the amount of deionized water is 80 parts. Stir at 100rpm for 25min, 600W ultrasonic dispersion for 20min, transfer to a four-necked flask, and heat up to 75° C., add 0.4 parts of potassium persulfate, and keep warm for 3 hours to obtain a nano-titanium dioxide/acrylate polymer composite emulsion.

(2) Preparation of anti-ultraviolet exterior wall coating

1) Weigh the material according to the formula, add deionized water, ethanol, polyoxyethylene alkylphenyl ether, AMP-95, and 1,2-propanediol in sequence under stirring at 1300rpm, and stir thoroughly for 20 minutes to obtain a prepolymer material.

2) Under stirring at 1300rpm, add the formulated amount of titanium dioxide and mica powder to the above prepolymer material, mix well and then stir at a high speed of 1700rpm for 40min to obtain a dispersion slurry of pigments and fillers.

3) Fully disperse the nano-titanium dioxide/acrylate polymer composite emulsion in the pure acrylic emulsion, slowly add ethylene glycol into the above-mentioned mixed emulsion under stirring at 500rpm, stir for 10min, add the obtained mixed solution into the pigment and filler dispersion slurry, and then Add 1,2-propanediol and propylene glycol under stirring at 800 rpm, and stir for 20 minutes.

4) Adjust the pH to 8 with ammonia water, add hydroxymethyl cellulose, and stir at 800 rpm for 20 minutes to obtain an anti-ultraviolet exterior wall coating.

Example 3

In terms of parts by mass, the formula of the anti-ultraviolet exterior wall paint consists of:

Ethylene Propylene Emulsion 33

Nano titanium dioxide/acrylate polymer composite emulsion 9

Titanium dioxide 7

Kaolin 14

Ethylene glycol 1.5

Propylene glycol 0.2

Hexylene glycol 1.8

2-Amino-2-methyl-1-propanol 0.5

Octanol 0.3

Hydroxyethylcellulose 0.2

BIT 0.3

Ammonia 0.1

AMP-95 0.1

Deionized water 32

Prepare UV-resistant exterior paints as follows:

(1) Preparation of Nano Titanium Dioxide/Acrylic Ester Polymer Composite Emulsion

1) Preparation of modified nano titanium dioxide

In terms of parts by mass, mix 2.25 parts of nano-titanium dioxide with 110 parts of methanol, 600W ultrasonic dispersion for 10 minutes, add 2.25 parts of γ-methacryloxypropyltrimethoxysilane, react at 60°C for 3.5h, centrifuge, and use Washing with absolute ethanol, centrifugation and washing were repeated 3 times, and drying at 75° C. for 18 hours to obtain modified nano titanium dioxide.

2) Preparation of nano-titanium dioxide/acrylate polymer composite emulsion

In terms of parts by mass, 2.25 parts of modified nano-titanium dioxide were dispersed in a mixed solution of 20 parts of acrylate, 14.1 parts of tert-butyl methacrylate, 0.9 parts of acrylic acid and 1.25 parts of n-amyl alcohol, 800W ultrasonic dispersion for 30min, and added to Sodium oleate aqueous solution, wherein the amount of sodium oleate is 1.25 parts, the amount of deionized water is 70 parts, stirred at 250rpm for 20min, 800W ultrasonic dispersion for 20min, transferred to a four-necked flask, heated to 70°C, added 0.3 part of peroxide Hydrogen, heat preservation for 4 hours, to obtain nano-titanium dioxide/acrylate polymer composite emulsion.

(2) Preparation of anti-ultraviolet exterior wall coating

1) Weigh the material according to the formula, add deionized water, propylene glycol, 2-amino-2-methyl 1-propanol, AMP-95, octanol in sequence under stirring at 1100rpm, and stir thoroughly for 30 minutes to obtain a prepolymer material.

2) Under stirring at 1100rpm, add the formulated amount of titanium dioxide and kaolin to the above prepolymer material, mix well and then stir at a high speed of 1500rpm for 50min to obtain a dispersion slurry of pigments and fillers.

3) Fully disperse the nano-titanium dioxide/acrylate polymer composite emulsion in the ethylene-propylene emulsion, slowly add ethylene glycol into the above-mentioned mixed emulsion under stirring at 450rpm, stir for 20min, add the obtained mixed solution into the pigment and filler dispersion slurry, and then Add octanol and hexanediol under stirring at 750rpm, and stir for 30min.

4) Adjust the pH to 8 with ammonia water, add hydroxyethyl cellulose, and stir at 750 rpm for 30 minutes to obtain an anti-ultraviolet exterior wall coating.

Example 4

In terms of parts by mass, the formula of the anti-ultraviolet exterior wall paint consists of:

Tert-acrylic emulsion 35

Nano titanium dioxide/acrylate polymer composite emulsion 11

Titanium dioxide 7

Barium sulfate 12

Propylene glycol 1.2

Glycerin 0.1

Propylene glycol butyl ether 1.5

Sodium oleate 0.4

Tributyl phosphate 0.2

Methylcellulose 0.2

CMIT/MIT0.2

AMP-95 0.1

Sodium hydroxide 0.1

Deionized water 31

Prepare UV-resistant exterior paints as follows:

(1) Preparation of Nano Titanium Dioxide/Acrylic Ester Polymer Composite Emulsion

1) Preparation of modified nano titanium dioxide

In terms of parts by mass, mix 2 parts of nano-titanium dioxide with 150 parts of ethanol, 400W ultrasonic dispersion for 30 minutes, add 1.8 parts of vinyltriethoxysilane, react at 65°C for 4 hours, centrifuge, wash with absolute ethanol, centrifuge and wash Repeat 3 times, and bake at 70° C. for 18 hours to obtain modified nano-titanium dioxide.

2) Preparation of nano-titanium dioxide/acrylate polymer composite emulsion

In terms of parts by mass, 2 parts of modified nano-titanium dioxide are dispersed in a mixture of 20 parts of methyl methacrylate, 18.8 parts of 2-ethyl acrylate, 1.2 parts of acrylic acid and 0.5 parts of cetyl alcohol, 400W Ultrasonic dispersion for 20 minutes, added to the aqueous solution of sodium lauryl sulfate, wherein the amount of sodium lauryl sulfate is 1.2 parts, the amount of deionized water is 70 parts, stirred at 200 rpm for 17 minutes, 800W ultrasonic dispersion for 40 minutes, transferred to the four The flask was heated up to 70° C., 0.35 parts of ammonium persulfate was added, and the temperature was kept for 4 hours to obtain a nano-titanium dioxide/acrylate polymer composite emulsion.

(2) Preparation of anti-ultraviolet exterior wall coating

1) Weigh the materials according to the formula, add deionized water, PE-100, sodium oleate, AMP-95, and tributyl phosphate in sequence under stirring at 1000 rpm, and stir thoroughly for 40 minutes to obtain a prepolymer material.

2) With stirring at 1000rpm, add the formulated amount of titanium dioxide and barium sulfate to the above prepolymer material, mix well and then stir at 1500rpm for 70min to obtain a dispersion slurry of pigment and filler.

3) Fully disperse the nano-titanium dioxide/acrylate polymer composite emulsion in the tertiary acrylic emulsion, slowly add the antifreeze agent into the above-mentioned mixed emulsion under stirring at 400rpm, stir for 30min, add the obtained mixed solution into the pigment and filler dispersion slurry, and then Add tributyl phosphate and propylene glycol butyl ether under stirring at 750 rpm, and stir for 40 minutes.

4) Adjust the pH to 9 with sodium hydroxide, add methyl cellulose, and stir at 750 rpm for 40 minutes to obtain an anti-ultraviolet exterior wall coating.

Example 5

In terms of parts by mass, the formula of the anti-ultraviolet exterior wall paint consists of:

Silicone acrylic emulsion 38

Nano titanium dioxide/acrylate polymer composite emulsion 13

Titanium dioxide 6

Kaolin 9

Propylene Glycol 1.5

PE-100 0.2

Ethylene glycol butyl ether 1.5

Sodium polyacrylate 0.3

Emulsified simethicone 0.1

Xanthan gum 0.1

CMIT/MIT0.1

AMP-95 0.1

Potassium hydroxide 0.1

Deionized water 30

Prepare UV-resistant exterior paints as follows:

(1) Preparation of Nano Titanium Dioxide/Acrylic Ester Polymer Composite Emulsion

1) Preparation of modified nano titanium dioxide

In terms of parts by mass, mix 0.9 parts of nano-titanium dioxide with 50 parts of ethanol, 700W ultrasonic dispersion for 10 minutes, add 1 part of vinyltrimethoxysilane, react at 60°C for 3.5 hours, centrifuge, wash with absolute ethanol, centrifuge and wash Repeat 3 times, and bake at 60° C. for 20 hours to obtain modified nano-titanium dioxide.

2) Preparation of nano-titanium dioxide/acrylate polymer composite emulsion

In terms of parts by mass, disperse 0.9 parts of modified nano-titanium dioxide in a mixed solution of 15 parts of methyl methacrylate, 14.1 parts of tert-butyl methacrylate and 0.5 parts of hexadecane, 500W ultrasonic dispersion for 35min, and add to ten Dialkyl sodium sulfate aqueous solution, wherein the amount of emulsifier is 1.2 parts, the amount of deionized water is 60 parts, stirred at 300rpm for 15min, ultrasonically dispersed at 700W for 30min, transferred to a four-necked flask, heated to 75°C, added 0.25 parts of Potassium sulfate, heat preservation for 4 hours, to obtain nanometer titanium dioxide/acrylate polymer composite emulsion.

(2) Preparation of anti-ultraviolet exterior wall coating

1) Weigh the material according to the formula, add deionized water, PE-100, sodium polyacrylate, AMP-95, and emulsified dimethyl silicone oil in sequence under stirring at 500 rpm, and stir thoroughly for 50 minutes to obtain a prepolymer material.

2) With stirring at 500 rpm, add the formulated amount of titanium dioxide and kaolin to the above-mentioned prepolymer material, mix well, and stir at 1000 rpm for 80 minutes to obtain a dispersion slurry of pigments and fillers.

3) Fully disperse the nano-titanium dioxide/acrylate polymer composite emulsion in the silicon-acrylic emulsion, slowly add propylene glycol into the above mixed emulsion under stirring at 300rpm, stir for 30min, add the obtained mixed solution into the pigment and filler dispersion slurry, and then add the mixed solution at 500rpm Add emulsified simethicone and ethylene glycol butyl ether under stirring, and stir for 50 minutes.

4) Adjust the pH to 8.5 with potassium hydroxide, add xanthan gum, and stir at 500 rpm for 50 minutes to obtain an anti-ultraviolet exterior wall coating.

Example 6

In terms of parts by mass, the formula of the anti-ultraviolet exterior wall paint consists of:

Styrene Acrylic Lotion 40

Nano titanium dioxide/acrylate polymer composite emulsion 15

Titanium dioxide 6

Talc 15

Propylene glycol 1.2

PE-100 0.2

Ethylene glycol butyl ether acetate 1.2

Sodium polyisobutylene maleate 0.3

Polyoxyethylene polyoxypropanolamine ether 0.4

TT-935 0.4

DBNPA 0.2

AMP-95 0.05

Ammonia 0.05

Deionized water 20

Follow the steps below to prepare a UV-resistant exterior paint

(1) Preparation of Nano Titanium Dioxide/Acrylic Ester Polymer Composite Emulsion

1) Preparation of modified nano titanium dioxide

In terms of parts by mass, mix 0.25 parts of nano-titanium dioxide with 20 parts of methanol, 500W ultrasonic dispersion for 5 minutes, add 0.1 part of vinyltrimethoxysilane, react at 60°C for 1 hour, centrifuge, wash with absolute ethanol, repeat centrifugation and washing 3 times, after baking at 80° C. for 16 hours, the modified nano-titanium dioxide was obtained.

2) Preparation of nano-titanium dioxide/acrylate polymer composite emulsion

In terms of parts by mass, disperse 0.25 parts of modified nano-titanium dioxide in 10 parts of methyl methacrylate, 10 parts of 2-ethyl acrylate and 0.5 parts of cyclohexanol mixture, 600W ultrasonic dispersion for 10 minutes, add In sodium dodecylbenzenesulfonate and polyoxyethylene sorbitan trioleate aqueous solution, wherein the amount of sodium dodecylbenzenesulfonate is 0.3 parts, polyoxyethylene sorbitan trioleate The amount of deionized water is 0.2 parts, the amount of deionized water is 40 parts, stirred at 200 rpm for 5 minutes, 600W ultrasonic dispersion for 10 minutes, transferred to a four-necked flask, heated to 80 °C, added 0.25 parts of potassium persulfate-sodium bisulfite, and kept for 2 hours. A nanometer titanium dioxide/acrylate polymer composite emulsion is obtained.

(2) Preparation of anti-ultraviolet exterior wall coating

1) Weigh the material according to the formula, add deionized water, PE-100, polyisobutylene maleate sodium salt, AMP-95, polyoxyethylene polyoxypropanolamine ether in sequence under stirring at 750rpm, and stir fully for 60min. A prepolymerized material is obtained.

2) With stirring at 750 rpm, add the formulated amount of titanium dioxide and talcum powder to the above prepolymer material, mix evenly, and stir at 1250 rpm for 90 minutes to obtain a dispersion slurry of pigment and filler.

3) Fully disperse the nano-titanium dioxide/acrylate polymer composite emulsion in the styrene-acrylic emulsion, slowly add propylene glycol into the above-mentioned mixed emulsion under stirring at 600rpm, stir for 30min, add the obtained mixed solution into the pigment and filler dispersion slurry, and then Add polyoxyethylene polyoxypropanolamine ether and ethylene glycol butyl ether acetate under rapid stirring, and stir for 60 minutes.

4) Adjust the pH to 9 with ammonia water, add TT-935, and stir at 700 rpm for 60 minutes to obtain an anti-ultraviolet exterior wall coating.

Test instruction

Example 1 prepares nano-titanium dioxide/acrylate polymer composite emulsion and anti-ultraviolet exterior wall paint to test:

TEM: Dilute the sample with deionized water to a solid content of about 0.3%, drop it on a 400-mesh carbon-coated copper grid, and use it for TEM testing after natural drying. A transmission electron microscope TECNAI 12 (FEI Electron Optics Co., Ltd., Netherlands) was used, and the accelerating voltage was 80KV during operation.

SEM: Dilute the sample with deionized water to a solid content of about 0.3%, drop it on the tinfoil on the conductive adhesive, and use it for SEM test after natural drying. A NOVA NANOSEM 430 high-magnification scanning electron microscope from the Netherlands was used, with an accelerating voltage of 20KV, a scanning period of 100s, a pulse count rate of 2000cps, and a working distance of 34mm.

EDS: EDS is connected to SEM.

The UV protection performance of the paint film is tested by an accelerated aging instrument. The UV light source is a UVA-340nm lamp tube, and the radiation intensity is 0.60W/m ² ;

Determine the hardness of the paint film according to GB/T 6739-2006;

Determination of water resistance of paint film according to GB 5209-1985;

Determine the alkali resistance of the paint film according to GB 9274-1988;

The scrub resistance of the paint film was determined according to GB/T9266-88.

It can be seen from Figure 1 that the nano-titanium dioxide is all distributed on the acrylate polymer microspheres, and the dispersion is excellent. It can be seen from Figure 2 that the surface of the acrylate polymer is smooth, and the nano-titanium dioxide is not on its surface, and Figure 3 shows that the composite microspheres The titanium element contained in the ball indicates that the nano-titanium dioxide is distributed inside the acrylate polymer microsphere, and its structure is a core-shell structure with the nano-titanium dioxide as the core and the acrylate polymer as the shell.

Table 1 Performance test results of UV-resistant exterior wall coatings

The data in table 1 shows that the coating of the present invention has good storage stability, and the hardness of the paint film is high, which is conducive to resisting physical damage; water resistance, acid and alkali resistance and scrub resistance are excellent; the anti-ultraviolet performance has surpassed the superior product The standard (600h).

The detection conditions all exceed the standard of high-quality products. Compared with the Chinese invention patent application CN102134424A, the coating obtained in CN102134424A has begun to yellow and pulverize after more than 200 hours. In this prior art, nano-titanium dioxide is directly added to the coating. The diameter is small, the relative area is large, and the surface is rich in hydroxyl groups, which are easy to agglomerate in the coating, and the ultraviolet shielding performance of the agglomerates is greatly reduced. The performance of the product obtained by the invention is far better than that of CN102134424A.

What needs to be emphasized is that the present invention not only coats a layer of acrylate polymer on the surface of nano-titanium dioxide, but also controls the coating process and the entire anti-ultraviolet exterior wall coating formula system rationally, so that the surface of nano-titanium dioxide is coated and then coated. Added to the exterior wall paint, the acrylate polymer on the surface of nano-titanium dioxide participates in the film formation of the exterior wall paint. This synergistic effect not only makes the paint film excellent in UV protection, but also improves the hardness and scrub resistance of the paint film. See Table 1 for specific performance testing.

Claims (10)

1. a kind of antiultraviolet exterior coating, it is characterised in that according to the mass fraction, its raw material includes following component：

Acrylate polymer emulsion 25~40

Nano titanium oxide/acrylate polymer complex emulsions 5~15

Color stuffing 15~25

Antifreezing agent 1.2~1.5

Wetting agent 0.1~0.2

Coalescents 1.2~1.8

Dispersant 0.3~0.6

Defoamer 0.1~0.4

Thickener 0.1~0.4

Preservative 0.1~0.3

PH adjusting agent 0.1~0.2

Deionized water 20~40

Described acrylate polymer emulsion be admittedly containing 40% styrene-acrylic emulsion, pure-acrylic emulsion, vinyl acetate emulsion, tertiary acrylic emulsion or Silicone acrylic emulsion；

Described nano titanium oxide/acrylate polymer complex emulsions latex particle with nano titanium oxide as core, propylene Acid ester polymer is the core shell structure of shell, is prepared as follows：

(1) modified nano-titanium dioxide is prepared

According to the mass fraction, ultrasonic disperse after 0.25~5 part of nano titanium oxide is mixed with 20~200 parts of solvents, adds 0.1 ~5 parts of silane couplers, 60~80 DEG C of 1~6h of reaction, centrifugation, with absolute ethanol washing, centrifugation, washing, drying is modified Nano titanium oxide；Described solvent is methyl alcohol, ethanol, isopropanol or acetone；Described silane coupler is γ-metering system One kind in acryloxypropylethoxysilane trimethoxy silane, vinyltrimethoxy silane or VTES；

(2) nano titanium oxide/acrylate polymer complex emulsions are prepared

According to the mass fraction, by 0.25~5 part of modified nano-titanium dioxide be dispersed in 20~50 parts of acrylate monomers and 0.5~ In 2 portions of mixed liquors of assistant for emulsifying agent, ultrasonic disperse is added in emulsifier aqueous solution, and wherein the amount of emulsifying agent is 0.5~2 part, The amount of deionized water is 40~80 parts, stirring, and ultrasonic disperse is warming up to 60~80 DEG C, adds 0.25~5 part of initiator, insulation 2 ~6h, obtains nano titanium oxide/acrylate polymer complex emulsions；Described acrylate monomer is methyl methacrylate Ester, Tert-butyl Methacrylate, acrylamide, butyl acrylate, acrylic acid-2-ethyl ester, hydroxy-ethyl acrylate, metering system One or more in acid and acrylic acid；Described assistant for emulsifying agent is hexadecane, hexadecanol, n-amyl alcohol or cyclohexanol；Described Emulsifying agent is enuatrol, lauryl sodium sulfate, neopelex, Tween 80, polysorbas20, alkylphenol-polyethenoxy The sorbitan monostearate of ether -10, polyoxyethylene 20 sorbitan trioleate and polyoxyethylene sorbitan list are hard One or more in resin acid ester；Described initiator is hydrogen peroxide, potassium peroxydisulfate, ammonium persulfate or potassium peroxydisulfate-sulfurous One kind in sour hydrogen sodium.

2. antiultraviolet exterior coating according to claim 1, it is characterised in that described color stuffing is titanium dioxide, weight One or more in calcium powder, talcum powder, barium sulfate, mica powder and kaolin；Described antifreezing agent is ethylene glycol or propane diols； Described wetting agent is PE-100, ethanol, propane diols or glycerine.

3. antiultraviolet exterior coating according to claim 1, it is characterised in that described by 0.25~5 part of nano-silica It is that power is 400~800W ultrasonic disperses, 5~30min to change ultrasonic disperse after titanium mixes with 20~200 parts of solvents.

4. antiultraviolet exterior coating according to claim 1, it is characterised in that the drying is in 50~100 DEG C of bakings 12~24h.

5. antiultraviolet exterior coating according to claim 1, it is characterised in that described to prepare nano titanium oxide/the third The ultrasonic disperse of olefine acid ester polymer complex emulsions is all for 400~800W disperses 10~60min in ultrasonic power；The preparation The stirring of nano titanium oxide/acrylate polymer complex emulsions be rotating speed be 100~400rpm under the conditions of stirring 5~ 30min。

6. antiultraviolet exterior coating according to claim 1, it is characterised in that described dispersant is dodecyl sulphur Sour sodium, polyoxyethylene alkyl phenyl ether, 2-amino-2-methyl-1-propanol, enuatrol, Sodium Polyacrylate or polyisobutene are along fourth Enedioic acid sodium salt；Coalescents are ethylene glycol, propane diols, hexylene glycol, propandiol butyl ether, butyl glycol ether, xylyl alcohol or second Glycol monobutyl ether acetate.

7. antiultraviolet exterior coating according to claim 1, it is characterised in that described defoamer is butanol, 1,2- Propane diols, octanol, tributyl phosphate, emulsification dimethicone, emulsification polymethylphenyl siloxane fluid, polyoxyethylene polyoxypropylene pentaerythrite Ether or polyoxyethylene polyoxy propyl alcohol amidogen ether.

8. antiultraviolet exterior coating according to claim 1, it is characterised in that described thickener is phthalic acid Dibutyl ester, hydroxymethyl cellulose, hydroxyethyl cellulose, methylcellulose, xanthans, XG-60, XG-903, SN-612 or TT- 935。

9. antiultraviolet exterior coating according to claim 1, it is characterised in that described preservative is BIT, BIT/ One kind in MIT, CMIT/MIT or DBNPA；Described pH adjusting agent is in AMP-95, ammoniacal liquor, NaOH or potassium hydroxide One or more.

10. the preparation method of the antiultraviolet exterior coating described in any one of claim 1-9, it is characterised in that including following step Suddenly：

(1) nano titanium oxide/acrylate polymer complex emulsions are prepared；

(2) it is prepared according to the following steps antiultraviolet exterior coating：

1) material is weighed by formula, sequentially adding deionized water, wetting agent, dispersant, pH under 500~1500rpm stirrings adjusts Section agent, defoamer, are sufficiently stirred for 10~60min, obtain prepolymerization material；

2) under 500~1500rpm stirrings, the color stuffing of formula ratio is added in the prepolymerization material, after being well mixed 1000~2000rpm stirs 30~90min, obtains color stuffing dispersion pulp；

3) nano titanium oxide/acrylate polymer complex emulsions are well dispersed in acrylate polymer exterior wall emulsion In, antifreezing agent is slowly added in above-mentioned mixed emulsion under 300~600rpm stirrings, 10~30min is stirred, it is mixed what is obtained Close liquid and add color stuffing dispersion pulp, then addition defoamer, coalescents under 500~1000rpm stirrings, stirring 10~ 60min；

4) pH to 8~9 is adjusted with pH adjusting agent, adds thickener, 500~1000rpm to stir 10~60min, obtain UV resistance Line exterior coating.