CN1546584A - A kind of environment-friendly photocatalytic exterior wall paint and preparation method thereof - Google Patents

Abstract

The invention relates to an air purification photocatalytic exterior wall paint and a preparation method thereof. It belongs to the technical field of building material manufacturing technology. It is characterized in that the inorganic/organic composite emulsion is used as the film-forming material, and the photocatalyst _TiO2 is dispersed in it in the form of functional filler, and supplemented with auxiliary agents and other functional additives to prepare a water-based environmental protection coating cured at room temperature. Among them, the photocatalyst is mainly titanium dioxide composed of a single anatase phase or a mixed phase of anatase phase and rutile phase, and the surface is coated with different oxides to meet the needs of different systems, that is, surface-modified titanium dioxide. This photocatalytic exterior wall coating can effectively degrade pollutants in the atmosphere, such as NO, _SO2, etc., and play a role in purifying the atmosphere.

Description

A kind of environment-friendly photocatalytic exterior wall paint and preparation method thereof

technical field

The invention relates to an air purification photocatalytic exterior wall coating and a preparation method thereof. It belongs to the technical field of building material manufacturing technology.

Background technique

Titanium dioxide photocatalyst generates electrons with strong reduction activity and holes with strong oxidation activity under the irradiation of light waves with a wavelength not smaller than the band gap energy, and decomposes molecular substances in contact with semiconductors through oxidation-reduction activity. When this photocatalytic technology is applied in the field of air purification, it is used to degrade NO, SO ₂ , ammonia and other toxic and harmful gases of small organic molecules in the outdoor air.

Chinese patent CN1397377 proposes dissolving titanium alkoxide in an alcohol solvent, adding water and carbon black to make a coating slurry, coating it on a substrate by leaching, and obtaining a titanium dioxide photocatalytic film after repeated firing. The Chinese patent CN1354042 proposes a magnetron sputtering film-forming method, which uses a direct synthesis of pure metal titanium targets and oxygen to form films on carriers such as glass, metal, and ceramics. This kind of photocatalytic coating has high cost and limited application range. Japanese patent application publication level 4-334552 is to bond photocatalyst particles by heating and melting a kind of fluorinated high polymer; The photocatalyst powder is exposed from the adhesive layer, then heated to 300°C-900°C to melt the adhesive layer, and then cooled to solidify. These two preparation methods all involve high-temperature treatment on the surface of the substrate, so it is difficult to use for some materials that are not resistant to high temperature, such as plastic surfaces. Chinese patent 1427052A discloses a preparation method of nano-photocatalytic polyurethane coating. The coating is composed of nano-slurry and modified synthetic resin, but it needs to be cured by a curing agent, which is inconvenient for construction. International patent WO97/00134 discloses a photocatalytic carrier structure consisting of a photocatalyst layer, a carrier, and an intermediate bonding layer. The junction layer and photocatalyst layer must be heated to cure. Chinese patent 1422920A discloses a preparation method of a photocatalytic material assembled from variable-valence rare earth elements and layered nanostructure substances and an air-purifying exterior wall coating composition containing the material. The preparation method of the photocatalytic material is cumbersome and the production cost is high. High, affecting the practical promotion of this kind of coating. Chinese patent 1424365A discloses a method for preparing a nano-titanium dioxide photocatalytic bactericidal degradable coating. The coating uses silicate as a film-forming substance and sodium fluorosilicate as an inorganic curing agent, but it needs to be cured at room temperature for more than 48 hours, or 80 It is not suitable for large-scale exterior wall coating construction. Chinese patent 1450129 proposes to disperse titanium dioxide in a silica carrier, add acrylic resin, water and additives to form a light-irradiated catalytic coating, which cannot completely cover the color of the wall, and is not suitable for use as an air-purifying coating for exterior walls.

Contents of the invention

An object of the present invention is to provide a kind of exterior wall paint mainly composed of oxidation-resistant, weather-resistant inorganic and organic composite emulsion (renamed "and") titanium dioxide photocatalyst capable of purifying the atmosphere. Another object of the present invention is to provide a method for preparing the photocatalytic exterior wall paint.

The purpose of the present invention is achieved through the following technical solutions:

An environment-friendly photocatalytic exterior wall paint, mainly made of raw materials such as organic resin emulsion, inorganic binder, photocatalyst, pigment, filler, auxiliary agent or additive, is characterized in that the components of the photocatalytic exterior wall paint and The weight percentage is:

Organic emulsion 10-35% Silica sol 5-15%

Photocatalyst 2-15% Pigment, filler 10-20%

Auxiliary additives 1-2% Solvent water 20-30%;

Among them, the organic emulsion is: one or more mixed emulsions of organic fluorine emulsion, silicone emulsion, and polyacrylate emulsion;

The inorganic binder is: silica sol;

The photocatalyst is: anatase phase titanium dioxide, or titanium dioxide composed of a mixture of anatase phase and rutile phase; or surface-modified titanium dioxide;

The pigment is titanium dioxide, and the filler is heavy calcium carbonate, talcum powder, kaolin map, and aluminum silicate;

Auxiliaries or additives include: dispersant polycarboxylate, defoamer polysiloxane, wetting agent modified alkylphenol polyoxyethylene ether.

A kind of manufacturing method of environment-friendly photocatalytic exterior wall paint of the present invention is characterized in that, the method comprises the following process steps and procedures:

a. Put the photocatalyst titanium dioxide into a sand mill, add water and a certain amount of dispersant polycarboxylate, and mix and grind to make a slurry with a certain concentration; the concentration of the photocatalyst slurry is 10-40%, the best is 30%;

b. Add pigments, filler additives, and additives into a high-speed disperser, and add a certain amount of dispersant polycarboxylate to make a slurry;

c. Mix the organic polymer emulsion, silica sol, photocatalyst and the above slurry under low shear, add the thickener dropwise to reach the required viscosity, and stir for 1 hour to prepare the photocatalytic exterior wall coating.

In the process of making, the dosage of the photocatalyst is 30-40% of the mass of the composite emulsion.

In the photocatalytic exterior wall paint prepared by the method of the present invention, the photocatalyst is mainly composed of a single anatase phase or titanium dioxide composed of a mixed phase of anatase phase and rutile phase, and the requirements of different systems can be realized if the surface is modified.

The photocatalytic functional coating of the present invention is coated on the surface of the material, and can effectively degrade pollutants in the surrounding atmosphere, such as automobile exhaust NO, _SO2, etc., under the irradiation of rays with a wavelength not smaller than the energy of the band gap. Light sources for irradiation include sunlight, fluorescent lamps, black lights, halogen lamps, mercury lamps, and the like. The preferred light source wavelength is near ultraviolet 300-400nm. After testing, the glass plate coated with the photocatalytic coating prepared by the method of the present invention is put into the flow tube type reaction device, and the _SO2 /NO with a concentration of 5ppm is introduced into the reactor, and the flow rate is 40ml/min. The corresponding residence time of the gas is 3.75min, and the average removal rate of SO ₂ /NO is about 80% when the ultraviolet light source is connected.

After testing, the photocatalytic functional coating prepared by the method of the present invention meets the main standards of GB/T 9755-2001 "Synthetic Resin Emulsion Exterior Wall Coatings", and various tests and standards are shown in the following table.

Table Coating Properties Test items technical indicators state in container After stirring and mixing, there is no hard lump and it is in a uniform state Construction Brushing two coats without barriers Solid content (%) 48-50% Coating Appearance normal Drying time/h 1 water resistance 96h no abnormality Alkali resistance 48h no abnormality Scrub resistance, times 1000 passes Stain resistance (white and light color1 ⁾ )/% 17 Coating resistance to temperature denaturation (5 cycles) No abnormality contrast ratio 0.89 weather resistance 500h no blistering, no peeling, no cracks

Detailed ways

Specific embodiments of the present invention are now described in the following:

Embodiment 1: First take the anatase phase nano-titanium dioxide TiO ₂ (A), add appropriate amount of water and dispersant polycarboxylate, and sand grind for 6 hours at a speed of 4000 rpm in a sand mill to obtain 30% nano Photocatalyst dispersion.

Weigh 20 grams of water, 10 grams of pigment titanium dioxide, 15 grams of heavy calcium carbonate filler, 4 grams of talcum powder, 3 grams of kaolin, 1 gram of aluminum silicate, 1 gram of polysiloxane defoamer, and modified alkanes as wetting agent. Base phenol polyoxyethylene ether 2 grams, stirred at high speed for 1 hour, then added 6.67 grams of the above-mentioned photocatalyst dispersion liquid, and stirred at high speed for 30 minutes to obtain a mixed slurry, also called pigment paste.

Under low-speed stirring, 25 grams of organic fluorine emulsion and 11.33 grams of water were added to the above-mentioned pigment slurry, and after stirring and dispersing for 30 minutes, a photocatalytic exterior wall paint was obtained.

The paint of the above formula was coated on an asbestos cement board of 150mm×70mm×(4-6)mm, and dried at room temperature for 1 hour to become the photocatalytic coating (sample a) of the present invention.

Embodiment 2: The preparation method of this embodiment is the same as the previous embodiment. Adopt the same pigment slurry as embodiment one. Add 10 grams of organic fluorine emulsion, 12 grams of acrylic acid emulsion, 10 grams of silica sol, and 4.33 grams of water under low-speed stirring, and stir and disperse for 30 minutes to obtain a photocatalytic exterior wall paint.

The paint of the above formula was coated on an asbestos cement board of 150mm×70mm×(4-6)mm, and dried at room temperature for 1 hr to become the photocatalytic coating (sample b) of the present invention.

Embodiment 3: The preparation method of this embodiment is the same as the previous embodiment. Adopt the same pigment slurry as embodiment one. Add 18 grams of silicone emulsion, 12 grams of acrylic emulsion, and 6.33 grams of water under low-speed stirring, and disperse for 30 minutes to obtain a photocatalytic exterior wall paint.

The paint of the above formula was coated on an asbestos cement board of 150mm×70mm×(4-6)mm, and dried at room temperature for 1 hr to become the photocatalytic coating (sample c) of the present invention.

Comparative example 1: using the same pigment paste as in Example 1. Add 30 grams of styrene-acrylic emulsion and 6.33 grams of water under low-speed stirring, and stir and disperse for 30 minutes to obtain a photocatalytic exterior wall paint.

The paint of the above formula was coated on a 150mm×70mm×(4-6)mm asbestos cement board, and dried at room temperature for 1 hr to form a photocatalytic coating (sample d).

The photocatalytic coating samples (asbestos cement board samples a-d) obtained in the above examples and comparative examples were equidistantly exposed to a 300w ultraviolet lamp. The results are shown in Table 1:

Table 1 UV resistance test results sample UV resistance test phenomenon Embodiment 1 Embodiment 2 Embodiment 3 Comparative Example 1 abcd After 63 hours, there is no abnormality After 63 hours, after 63 hours without abnormality, after 3 hours without abnormality, the edge turns yellow and no cracking, after 5 hours, there is a slight cracking

The test shows that the paint aging phenomenon can be observed on the samples a-c of the present invention, indicating that its film-forming substances are not easy to degrade. However, sample d of Comparative Example 1, which did not use any weather-resistant emulsion, showed obvious yellowing, indicating that the film-forming substance was decomposed by the photocatalytic action of titanium dioxide in the anatase phase.

Embodiment 4: take self-made anatase phase nano-titanium dioxide TiO ₂ (A), add appropriate amount of water and dispersant polycarboxylate, and sand mill for 6 hours at a speed of 4000 rpm in a sand mill to obtain 30% Nano-photocatalyst TiO ₂ dispersion.

Weigh 10 grams of water, 10 grams of pigment titanium dioxide, 12 grams of heavy calcium carbonate filler, 3 grams of talcum powder, 2 grams of kaolin, 1 gram of aluminum silicate, 1 gram of polysiloxane defoamer, and modified alkanes as wetting agent. Base phenol polyoxyethylene ether 1 g, dispersant polycarboxylate 2 g, stir in a mixer at high speed for 1 hour, then add 20 g of the above-mentioned photocatalyst titanium dioxide dispersion, and stir at high speed for 30 minutes to obtain a mixed slurry, also known as pigment pulp.

Under low-speed stirring, 18 grams of silicone emulsion, 12 grams of acrylic emulsion, and 6.33 grams of water were added to the above-mentioned paste, and after stirring and dispersing for 30 minutes, a photocatalytic exterior wall paint was obtained.

The paint of the above formula was coated on a glass plate of 18 mm×250 mm, and dried at room temperature for 1 hr to become the photocatalytic coating (sample e) of the present invention.

Embodiment five: take self-made Al ₂ O ₃ /TiO ₂ (A) photocatalyst (i.e. surface-modified TiO ₂ , add appropriate amount of water and dispersant polycarboxylate, in a sand mill at 4000 rev/min Sand milling at a rotational speed for 6 hours to obtain a 30% nano photocatalyst dispersion, the catalyst TiO ₂ being covered with Al ₂ O ₃ .

Weigh 10 grams of water, 10 grams of titanium dioxide, 12 grams of heavy calcium carbonate, 3 grams of talcum powder, 2 grams of kaolin, 1 gram of aluminum silicate, 1 gram of antifoaming agent polysiloxane, and wetting agent modified alkylphenol 1 gram of polyoxyethylene ether and 2 grams of dispersant polycarboxylate were stirred in a mixer at high speed for 1 hour, then 20 grams of the above-mentioned photocatalyst dispersion was added, and stirred at high speed for 30 minutes to obtain a mixed slurry, also known as pigment slurry.

Under low-speed stirring, 18 grams of silicone emulsion, 12 grams of acrylic emulsion, and 6.33 grams of water were added to the above-mentioned paste, and after dispersing for 30 minutes, a photocatalytic exterior wall paint was obtained.

The paint of the above formula was coated on a glass plate of 18 mm×250 mm, and dried at room temperature for 1 hr to become the photocatalytic coating (sample f) of the present invention.

Comparative example two: get anatase phase titanium dioxide (P25, German Degussa company), add appropriate amount of water and dispersant polycarboxylate, sand mill 6 hours with the rotating speed of 4000 rev/mins in sand mill, get 30% Nano photocatalyst dispersion.

Weigh 10 grams of water, 10 grams of titanium dioxide, 12 grams of heavy calcium carbonate, 3 grams of talcum powder, 2 grams of kaolin, 1 gram of aluminum silicate, 1 gram of antifoaming agent polysiloxane, and wetting agent modified alkylphenol 1 gram of polyoxyethylene ether and 2 grams of dispersant polycarboxylate were stirred in a mixer at high speed for 1 hour, 20 grams of the above-mentioned photocatalyst dispersion was added, and stirred at high speed for 30 minutes to obtain a mixed slurry, also called pigment slurry.

Under low-speed stirring, 18 grams of silicone emulsion, 12 grams of acrylic emulsion, and 6.33 grams of water were added to the above-mentioned paste, and after dispersing for 30 minutes, a photocatalytic exterior wall paint was obtained.

The paint of the above formula was coated on a glass plate of 18 mm x 250 mm, and dried at room temperature for 1 hr to obtain sample g.

Put the sample eh of the embodiment and the comparative example in the flow-through tube reaction device respectively, pass _SO2 /NO with a concentration of 5ppm into the reactor, the flow rate is 40ml/min, the corresponding residence time of the gas is 3.75min, and the UV light source. The results show that samples e and f of the present invention have excellent SO ₂ /NO removal effects. The removal amount of SO ₂ /NO for sample e is 4 ppm, the removal amount of SO ₂ /NO for sample f is 4.5 ppm, and the removal amount of SO ₂ /NO for sample g of the comparative example is 2.4 ppm.

Claims (3)

1. an environment-friendly type photochemical catalysis exterior coating mainly adopts raw materials such as organic resin emulsion, mineral binder bond, photocatalyst, pigment, filler, auxiliary agent or additive to make, and it is characterized in that the component of this photochemical catalysis exterior coating and weight percentage are:

Organic emulsion 10-35% silicon sol 5-15%

Photocatalyst 2-15% pigment, filler 10-20%

Promoter additive 1-2% aqueous solvent 20-30%;

Wherein, organic emulsion is: the mixed emulsion of one or more of organic fluorine emulsion, organic silicon emulsion, polyacrylate dispersion;

Mineral binder bond is: silicon sol;

Photocatalyst is: anatase phase titanium dioxide, perhaps mix the titanium dioxide of forming with rutile mutually mutually by anatase octahedrite; Or the titanium dioxide of surface modification;

Pigment is titanium dioxide, and filler is water-ground limestone, talcum powder, high mountain range figure, pure aluminium silicate;

Auxiliary agent or additive have: the dispersant polycarboxylate class, defoamer is polysiloxane-based, wetting agent modification alkylphenol polyoxyethylene.

2. the manufacture method of a kind of environment-friendly type photochemical catalysis exterior coating according to claim 1 is characterized in that, this method comprises following each processing step and program:

A. photocatalyst titanium dioxide is put into sand mill, add entry and add the certain amount of dispersant polycarboxylate, mix grinding is made certain density slurries; The concentration of photocatalyst slurries is 10-40%, and the best is 30%;

B. pigment, filler auxiliary agent, additive are added in the high speed dispersion device, and add a certain amount of dispersant polycarboxylate, make slurry;

C. with organic polymer emulsion, silicon sol, photocatalyst and above-mentioned slurries, under low the shearing, mix, after the dropping thickening material causes required viscosity, stir and promptly can be made into the photochemical catalysis exterior coating in 1 hour.

3. the manufacture method of environment-friendly type photochemical catalysis exterior coating according to claim 2 is characterized in that described photocatalyst, and its consumption is the best with the 30-40% of composite emulsion.