KR20190122177A - One-component Photo-catalytic Coating Composition and Method of Preparing the Same - Google Patents

Abstract

The present invention relates to a one-component water dispersion polyurethane composition comprising TiO_2 photocatalyst, which maintains a uniform mixed state not generating precipitation even in a mixed state before coating on an object to be deposited and does not need a separate hardener even though fixing force to the object to be deposited is high.

Description

One-component photo-catalytic coating composition and method of preparing the same}

The present invention relates to a one-part photocatalyst coating composition and a method for preparing the same, specifically, a uniform curing agent in which a precipitate does not occur even in a mixed state before coating on an object to be deposited, and having a high fixing power to the object to be deposited, It is directed to a one-part photocatalyst coating composition and a method for preparing the same.

A substance that receives light from the outside and promotes a chemical reaction is called a photocatalyst, and a reaction carried out by such a catalyst is called a photochemical reaction or a photocatalytic reaction. Representative examples of catalysts or enzymes for promoting the photochemical reaction include organic compounds such as organometallic compounds and pigments and natural substances of chlorophyll.

In general, the photocatalyst is mainly a metal oxide or sulfur compound containing a transition metal. Representative metal compounds exhibiting a photocatalytic effect include ZnO, WO ₃ , SnO ₂ , ZrO ₂ , TiO ₂ , CdS, CdSe, and the like. In particular, TiO ₂ photocatalyst has the advantage that it can be used semi-permanently because it is inexpensive, harmless to human body, and excellent in durability.

It is well known that the photocatalytic material exerts a photocatalytic effect due to the following reaction mechanism. When a certain area of light energy is applied to the photocatalytic material, a large amount of electrons (e ⁻ ) are excited from the valence band to the conduction band, and a large amount of holes (h ^{+ in the} valence band) ) Is formed. In this case, the hole (h ⁺ ) reacts with water to produce radical hydroxide (OH ⁻ ), and in the reverse reduction reaction, oxygen in the air is reduced to generate active oxygen of the superoxide anion (O ₂ ⁻ ). Since radical hydroxide has high oxidation and reduction potential, it has an excellent effect on NO _x , SO _x , volatile organic compounds (VOCs) removal and various odor purification.

The application of photocatalyst is very diverse. For example, it can be used for exterior walls of buildings to remove harmful substances such as formaldehyde, which is a cause of sick house syndrome, and to decompose and deodorize pollutants generated in offices or indoor spaces. . Removal of various organic substances and hazardous gases through industrial oxidation, decomposition reaction of hardly degradable dye wastewater, application to road surface or road pavement for removal of nitrogen oxides emitted from vehicles, washer for self-cleaning effect, air cleaner Applications in refrigerators, refrigerators and the like.

The photocatalytic material must be stably fixed to the deposited object for long term use. Due to the property of the inorganic photocatalyst and the reactivity of the photocatalyst itself, the fixing force on the deposited object is lowered. Therefore, the application of the photocatalyst is very limited.

In general, the method of immobilizing the photocatalyst material may be classified into an organic binder mixing method, an inorganic binder mixing method, a photocatalyst direct fixing method, and a two-component fixing method.

The organic binder mixing method is a method in which a photocatalyst material is mixed with an organic binder, and the mixture is applied to a deposition target or laminated. However, this method has a disadvantage in that weatherability is not good because the organic binder component is decomposed by the redox reaction of the photocatalytic material.

The inorganic binder mixing method improves the disadvantages of the organic binder mixing method, and uses an inorganic binder component mixed with a photocatalytic material instead of the organic binder. In this case, the inorganic binder component is not easily decomposed by the photocatalytic reaction, but since the inorganic binder component surrounds the photocatalytic material exhibiting the photocatalytic effect, the photocatalytic effect is substantially reduced.

The photocatalytic direct fixing method is a method of directly fixing a photocatalytic material to the surface of an object to be deposited without using an organic binder or an inorganic binder. This method has a merit that the photocatalytic material is directly fixed to the deposition object, and since there is no foreign matter, that is, a binder component around or on the surface thereof, the photocatalytic effect can be best exhibited in theory. However, after spraying the photocatalytic material on the deposited object, expensive equipment must be used to directly fix the photocatalytic material to the deposited object, and there is a disadvantage that the type of the deposited object that can use this method is too limited.

The two-part fixing method is a further improvement of the conventional methods mentioned above. First, an inorganic binder is applied to the surface of the object to be deposited to form an inorganic binder layer, and then a photocatalytic material is sprayed onto the inorganic binder layer to form a photocatalytic material. This is how you fix it. This method has the advantage that the photocatalytic material is not buried by the binder component, but has a disadvantage in that an operation of forming the inorganic binder layer on the object to be deposited and again forming the photocatalytic layer thereon is performed. In addition, there is also a disadvantage that should be used to limit the deposition target to a specific range.

In this regard, Patent Document 1 discloses a photocatalyst coating composition including a surfactant, but most of the surfactants are organic substances, and have a problem in that the fixing force to the deposition target is pointed out as a problem of the organic binder.

Although the usefulness of the photocatalytic material is recognized as described above, there is a high need for a technology capable of improving the binding force with the deposited object without limiting the object to which the photocatalytic material can be applied.

Korean Patent Publication No. 10-1487758

The present invention is to solve the problems as described above, even in the mixed state before coating on the target object to maintain a uniform mixed state that does not generate a precipitate, one-component type that does not require a separate curing agent with improved fixing force to the target object It is an object to provide a photocatalyst coating composition and a method for producing the same.

A first aspect of the present invention for achieving the above object is a one-component type comprising a water-dispersed polyurethane and a photocatalytic material prepared using a monomeric diisocyanate compound, a polycarbonate diol compound, a compound for introducing a hydrophilic group It provides a photocatalyst coating composition.

The second aspect of the present invention

As a method of preparing a one-part photocatalyst coating composition,

a) mixing a monomeric diisocyanate compound, a polycarbonate diol compound, a compound for introducing a hydrophilic group, a photocatalytic material, and then proceeding to obtain a NCO-terminated prepolymer;

b) neutralizing by adding a neutralizing agent to the prepolymer of step a);

c) adding water to the neutralized prepolymer of step b) to perform phase transition;

d) injecting a chain extender into the solution of step c);

It provides a method for producing a one-part photocatalyst coating composition comprising.

As described above, the one-part photocatalyst coating composition and the preparation method thereof according to the present invention can effectively attach the one-part photocatalyst coating composition to the surface of the object to be deposited with only one coating, and have a high dispersibility, so that it is uniform. Since the coating layer can be formed, the photocatalytic effect can be improved.

In addition, when used in asphalt roads or cement roads, it is possible to increase the strength of the road to obtain the effect of increasing the life, the resistance to slip is improved.

In addition, the one-part photocatalyst coating composition of the present application has a high permeability, thereby providing an effect of not changing the existing color of the roadway.

1 is a photograph showing the results of Example 1 in Experimental Example 1.
2 is a photograph showing the results of Comparative Example 1 in Experimental Example 1.
3 is a graph showing the reduction rate of nitrogen oxides when the first embodiment is applied to asphalt.
Figure 4 is a graph showing the nitrogen oxide reduction rate when the photocatalyst composition is not applied to asphalt.
5 is a photograph comparing the precipitation of the photocatalyst composition.

In order to achieve the above effects, the one-part photocatalyst coating composition of the present application comprises a monomeric diisocyanate compound, a polycarbonate diol compound, a water-dispersed polyurethane and a photocatalyst material prepared using a compound for introducing a hydrophilic group. Provided is a one-part photocatalyst coating composition.

Conventionally, in order to fix the photocatalyst composition to the deposition target, a method of dispersing a photocatalytic material combined with a surfactant in a binder is added to the deposition target. In this case, the photocatalytic composition is easily separated due to a weak fixing force on the deposition target. There was a problem.

In order to solve such a problem, the one-part photocatalyst coating composition of the present application is prepared by adding a photocatalytic material during the synthesis of the water-dispersed polyurethane, whereby the photocatalytic material is adsorbed onto the water-dispersed polyurethane, thereby Fixation force is improved. Polyurethane has a very good initial adhesive force by providing a uniform and thin coating surface on the surface. In addition, it is possible to form a micelle structure with titanium dioxide to strongly adhere to the surface of the adherend together with titanium dioxide. Polyurethane is environmentally friendly and odorless, providing convenience for construction.

In the preparation of the photocatalyst coating composition according to the present invention, monomeric diisocyanate compounds are preferred to polyisocyanate compounds. Specific examples of the monomeric diisocyanate compound include toluene diisocyanate (TDI), diphenylmethane 4,4'-diisocyanate (Diphenylmethane 4, 4'-Diisocyanate, MDI), diphenylmethane 2,4'- Diphenylmethane 4, 4'- Diisocyanate, Hexamethylene Diisocyanate (HDI), Bis (4-isocyanatocyclohexyl) Methane, Isophorone Diisocyanate , IPDI) may be selected, and most preferably isophore diisocyanate may be used.

In preparing the photocatalyst coating composition according to the present invention, polycarbonate diol-based compounds are preferred, and their number average molecular weight is 500 to 5,000.

The compound for introducing a hydrophilic group for improving water dispersibility is a lower alcohol compound having an organic acid value, specifically, dimethylol propionic acid (DMPA) or dimethylol butanoic acid, and most preferably dimethylol propionic acid may be used. have.

In the finally prepared photocatalytic coating composition, the weight average molecular weight of the water-dispersed polyurethane is preferably 10,000 to 100,000 g / mol.

The photocatalytic material generates a large amount of electrons (e ⁻ ) and a large amount of holes (h ⁺ ) in the material when a certain area of light energy is applied, and materials existing around the material by the electrons and holes. It is a substance that causes redox reaction against. Such photocatalyst materials may be semiconducting metal oxides, sulfur compounds or selenium compounds.

For example, the photocatalyst material may be at least one selected from the group consisting of ZnO, WO ₃ , SnO ₂ , ZrO ₂ , TiO ₂ , CdS, CdSe, and the photocatalyst material is used when processed into a fine powder form, The surface area is widened to increase the reaction part, which is advantageous for reactivity.

It is preferable to use titanium dioxide (TiO ₂ ) as the photocatalyst material, and the titanium dioxide exists in three forms, anatase type, rutile type, and brookite type, depending on the crystal arrangement.

Practical and widely used forms are the anatase and rutile forms of TiO ₂ , which can be easily crystallized at low temperatures. The anatase type has good surface activity and is sensitive to photoactive reactions, and the rutile type has a good white brightness and hiding power.

In the present invention, the above crystalline forms may be used alone, or may be used by mixing with each other. Therefore, it may be more efficient to mix and use the crystalline forms as appropriate. The mixing ratio is not particularly limited, and may be determined in an appropriate ratio depending on the environment used. For example, the photocatalytic material is titanium dioxide (TiO ₂ ), and the anatase type and the rutile type are 2: 8 to 8: Can be used in ratio of 2.

On the other hand, the titanium dioxide is more than 0% by weight 5% by weight or less, preferably more than 0% by weight 2% by weight, most preferably more than 0% by weight 0.5% by weight based on the total weight of the one-part photocatalyst coating composition It may be included in the following range.

When the titanium dioxide is included in more than the above range of the photocatalyst composition, it is not preferable because the transmittance is lowered and the color of the road surface may be changed to white.

Plasticizers, colorants, antifoams, and dispersants may be added to the one-part photocatalyst coating composition as necessary.

Plasticizers include general plasticizers such as dioctyl phthalate, dibutyl phthalate, dioctyl adipate, diisodecyl phthalate and diisononyl phthalate and flame retardant plasticizers such as triphenyl phosphate, tricresyl phosphate and trisisopropyl phenyl phosphate. It can be used alone or in combination depending on the 5 to 20% by weight.

As the colorant, colorants such as carbon black, titanium dioxide, chromium oxide green, chromium green, or mixed pigments colored by mixing organic pigments may be used within the range of 2 to 10% by weight.

Defoamers and dispersants can be used as other additives, which can be used in the range of 0.05 to 2.0% by weight, respectively.

The present invention provides a method for preparing a one-part photocatalyst coating composition as follows.

a) mixing a monomeric diisocyanate compound, a polycarbonate diol compound, a compound for introducing a hydrophilic group, a photocatalytic material, and then proceeding to obtain a NCO-terminated prepolymer;

b) neutralizing the prepolymer of step a) by adding a neutralizing agent after cooling;

c) generating water by introducing water into the neutralized prepolymer of step b);

d) injecting a chain extender into the solution of step c).

The method for preparing the water-dispersed polyurethane according to the present invention is added in the step of preparing the prepolymer, and since the titanium dioxide and the micelle structure are initially formed and uniformly dispersed, it penetrates into the asphalt voids and is uniform on the surface. Providing a thin coating surface improves the holding power of the photocatalytic material to the deposition object.

The neutralizing agent may be ammonia, ethylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, triethanolamine, N-methyldiethanolamine, N-phenyldiethanolamine, dimethylethanolamine, diethylethanolamine, A mixture of any one or more selected from morpholines, preferably triethylamine can be used.

The chain extender is a mixture of any one or more selected from ethylene diamine (EDA), butylenediamine, hexanediamine, isoprondiamine, diethylene triamine, triethylene tetraamine, hydrazine hydrate, preferably Hydrazine hydrate can be used.

In the following, it will be described with reference to the embodiment according to the present invention, but for the easier understanding of the present invention, the scope of the present invention is not limited thereto.

<Example 1>

15-25 wt% of isophore diisocyanate, 60-80 wt% of polycarbonate diol (number average molecular weight 1000), 5-15 wt% of dimethylol propionic acid and 0.5 wt% of titanium dioxide, followed by nitrogen atmosphere at 4 at 80 ° C. The reaction is carried out for 5 hours to prepare a prepolymer having a cyanate group located at its terminal.

For Example 1, 3 mol of isophore diisocyanate, 1 mol of polycarbonate diol (number average molecular weight 1000), 0.6 mol of dimethylol propionic acid, and 0.5 wt% of titanium dioxide were mixed, and then reacted at 4 ° C. under nitrogen atmosphere at 80 ° C. for 5 hours. A prepolymer was prepared in which the cyanate group was located at the end.

After cooling the prepolymer to 40 ° C. to 50 ° C., it is neutralized by adding 0.6 mole of triethylamine.

While maintaining the temperature, the deionized water was added dropwise to the neutralized product for 30 minutes, followed by stirring. 1.1 mole of a 10% by weight aqueous solution of hydrazine monohydrate was added, and a chain bonding reaction was conducted while maintaining 30 ° C to 40 ° C to prepare a water-dispersed polyurethane.

Comparative Example 1

A water-dispersed polyurethane was prepared in the same manner as in Example 1, except that 1.0 wt% was added instead of 0.5 wt% of titanium dioxide in Example 1.

Experimental Example 1

Road discoloration measurement

Part of the asphalt road was not coated with a photocatalyst composition, and part of the asphalt road was coated with the water-dispersed polyurethane compound prepared in Example 1 and Comparative Example 1 on the asphalt road, and after 1 hour, the asphalt road surface was discolored.

An asphalt road photograph coated with the photocatalyst composition of Example 1 is illustrated in FIG. 1, and an asphalt road photograph coated with the photocatalyst composition of Comparative Example 1 is illustrated in FIG. 2.

1 and 2, in the case of Example 1 containing 0.5 wt% of titanium dioxide, the same color as that of the non-coated photocatalyst composition was shown because of high transmittance. However, in the case of Comparative Example 1 containing 1% by weight of titanium dioxide it can be seen that the road surface discolored white.

Experimental Example 2

Slip resistance

The photocatalyst composition prepared in Example 1 was added to the asphalt road to measure slip resistance, and the slip resistance of the asphalt road that was not treated with the photocatalyst composition was measured. Sliding resistance was measured by the British Tendulum Tester (BPT), a portable friction tester. The results are shown in Table 1 below.

Sample aridity Wet state Untreated photocatalyst composition 83 71 Treatment of the Photocatalyst Composition of Example 1 101 72

Referring to Table 1, it can be seen that when the photocatalyst composition including titanium dioxide is added, it is improved by about 25% in the dry state as compared with the case where the photocatalyst composition is not added.

Experimental Example 3

NOx Reduction Experiment

The photocatalyst composition prepared in Example 1 was added to the asphalt road to measure the nitrogen oxide adsorption rate, and the asphalt nitrogen oxide adsorption rate without the photocatalyst composition treatment was measured, and the results are shown in FIGS. 3 and 4.

3 and 4, the nitrogen oxide reduction rate of the asphalt was measured for 4,200 seconds, since the change in the reduction rate is less than 600 seconds and 3,600 seconds to 4,200 seconds after the start of the irradiation, from 600 seconds to 3,600 seconds after the start of the irradiation The reduction rate of nitrogen oxides was compared.

Figure 3 shows the nitrogen oxide reduction rate of the asphalt treated with the photocatalyst composition of Example 1, 24.5% nitrogen oxides were reduced. In addition, it can be seen that the amount of nitrogen oxide reduction proceeds rapidly in the early stage. FIG. 4 shows the nitrogen oxide reduction rate of the asphalt which was not treated with the photocatalyst composition of Example 1, indicating that the nitrogen oxides of 2.9% were reduced. This is simply analyzed by the result of NO _x adsorbed on the asphalt surface.

That is, when the asphalt catalyst is treated with the photocatalyst composition of Example 1, it can be seen that nitrogen oxide is significantly reduced in a short time.

Comparative Example 2

A 2 liter container was prepared, and 5 g of titanium dioxide (TiO ₂ ) was added to 500 g of colloidal silica, and the mixture was slowly stirred. Then, 150 g of dodecyl sulfonic acid was weighed in and then continuously stirred for 1 hour.

While the stirring was continued, 1000 g of deionized water was weighed again in the vessel, and after further stirring for 30 minutes, the reaction solution was finally obtained.

Experimental Example 4

Precipitation Test

After leaving the photocatalyst coating composition prepared in Example 1 and Comparative Example 2 in a reaction container for 24 hours, it was confirmed whether it was precipitated and the results are shown in FIG. 5.

Referring to FIG. 5, the photocatalyst composition prepared in Example 1 is present in a uniform color as a whole, and no precipitate is formed at the bottom. However, the photocatalyst composition prepared in Comparative Example 2 is the upper portion of the photocatalyst composition of Example 1 It looks clear and you can see that a deposit is formed on the bottom.

Therefore, the photocatalyst composition prepared in Example 1 does not sink even before it is applied to the road, so that the composition of the coating layer is uniformly distributed even after application, since the photocatalyst composition is applied to the entire portion of the road to which the photocatalyst composition is applied. Uniform photocatalytic effect can be obtained.

Those skilled in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (14)

A one-component photocatalyst coating composition comprising a monomeric diisocyanate compound, a polycarbonate diol compound, a water dispersion polyurethane prepared using a compound for introducing a hydrophilic group, and a photocatalytic material. The method of claim 1,
The monomeric diisocyanate compound may include toluene diisocyanate (TDI), diphenylmethane 4,4'-diisocyanate (Diphenylmethane 4, 4'-Diisocyanate, MDI), diphenylmethane 2,4'-diisocyanate (Diphenylmethane 4, 4'- Diisocyanate), Hexamethylene Diisocyanate (HDI), Bis (4-isocyanatocyclohexyl) Methane, IsophoroneDiisocyanate (IPDI) At least one of the one-component photocatalyst coating composition is selected. The method of claim 1,
The number average molecular weight of the polycarbonate diol compound is 500 to 5,000 1-part photocatalyst coating composition. The method of claim 1,
Compound for the introduction of the hydrophilic group is a one-component photocatalyst coating composition is a lower alcohol compound having an organic acid value. The method of claim 4, wherein
The lower alcohol compound having the organic acid value is dimethylol propionic acid (dimethylol propionic acid, DMPA) or dimethylol butanoic acid one-component photocatalyst coating composition. The method of claim 1,
The weight average molecular weight of the water-dispersed polyurethane is 10,000 ~ 100,000g / mol 1-component photocatalyst coating composition. The method of claim 1,
When the photocatalyst material is applied with a certain area of light energy,
Semiconducting metal oxides, sulfur compounds, or selenium compounds that generate a large amount of electrons (e ⁻ ) and a large amount of holes (h ⁺ ), and cause redox reactions to substances that exist around the material by the electrons and holes Phosphorus 1-part photocatalyst coating composition. The method of claim 7, wherein
The photocatalyst material is at least one type of photocatalyst coating composition selected from the group consisting of ZnO, WO ₃ , SnO ₂ , ZrO ₂ , TiO ₂ , CdS, CdSe. The method of claim 8,
The photocatalyst material is titanium dioxide (TiO ₂ ) one-component photocatalyst coating composition. The method of claim 9,
The titanium dioxide is a one-component photocatalyst coating composition is contained in the range of more than 0% by weight 5% by weight based on the total weight of the one-component photocatalyst coating composition. The method of claim 1,
A one-part photocatalyst coating composition in which a plasticizer, a colorant, an antifoaming agent, and a dispersant may be added as necessary to the one-part photocatalyst coating composition. A method for preparing a one-part photocatalyst coating composition according to any one of claims 1 to 11,
a) monomeric diisocyanate compound, polycarbonate diol compound, parent
Admixing a compound for introducing an aqueous group and a photocatalyst material and then proceeding to obtain a NCO-terminated prepolymer;
b) neutralizing by adding a neutralizing agent to the prepolymer of step a);
c) phase transition by adding water to the neutralized prepolymer of step b)
system; And
d) injecting a chain extender into the solution of step c);
Method for producing a one-part photocatalyst coating composition comprising a. The method of claim 12,
The neutralizing agent is ammonia, ethylamine, trimethylamine, triethylamine, triiso
Propylamine, tributylamine, triethanolamine, N-methyl diethanolamine, N-phenyl diethanol
A method for producing a one-part photocatalyst coating composition, which is a mixture of any one or more selected from amine, dimethylethanolamine, diethylethanolamine, and morpholine. The method of claim 12,
The chain extender is ethylene diamine (Ethylene Diamine, EDA), butylenediamine,
A method for producing a one-part photocatalyst coating composition, which is a mixture of any one or more selected from hexanediamine, isoprondiamine, diethylene triamine, triethylene tetraamine, and hydrazine hydrate.

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