KR20130124601A - Method for photocatalyst coating on plastic - Google Patents

Abstract

The present invention relates to a manufacturing method which simply manufactures plastic coated with a photocatalyst within a short time at low temperatures by using microwave irradiation in a processing method for coating the photocatalyst of a titanium oxide precursor including titanium oxide nanoparticles and nickel oxide primers used for coating plastic with a photocatalyst. In the photocatalyst coated on the plastic, electrons and holes excited by ultraviolet ray and visible ray are separated and used in a chemical reaction without recombination, thereby increasing process efficiency more than two times in comparison with the conventional method. Additionally, plastic degradation due to the photocatalyst can be prevented. [Reference numerals] (AA) Titanium dioxide layer;(BB) Particle titanium dioxide layer;(CC) Nickel oxide layer

Description

Photocatalyst coated plastics {Method for photocatalyst coating on plastic}

The present invention relates to a manufacturing method for coating a photocatalyst on a plastic. More particularly, the present invention relates to a coating of nickel oxide primer on plastics and a method of coating a titanium oxide photocatalyst, and more particularly to titanium oxide containing nickel oxide primer and nanoparticle titanium oxide used to coat photocatalysts on plastics. The present invention relates to a method for coating a photocatalyst of a precursor, which is simply prepared at a low temperature within a relatively short time using microwave irradiation.

In general, when a photocatalyst receives light, the chemical state of the surface is changed to

It is a term that refers to a material that exhibits a catalytic function of promoting a reaction.

   The photocatalytic properties of titanium dioxide, a semiconductor material, are affected by UV light

It is derived from the movement of electrons from the valence band to the conduction band.

Materials currently studied to have activity as photocatalysts include metal oxides such as TiO, ZnO, NbO, WO, SnO, ZrO, composite metal oxides including SrTiO, KTaO, NiKNO17 including a plurality of metals thereof, CdS, Metal sulfides such as ZnS, metal chalcogenites such as CdSe, GaP, CdTe, MoSe, WSe, and the like. Among them, titanium oxide is preferably used in terms of excellent light efficiency and light corrosion resistance, and is harmless and inexpensive. .

The principle of such a photocatalyst is described with reference to FIG. 1 as follows. Anatase of titanium oxide used as a photocatalyst is a semiconducting metal oxide and has a bandgap energy of 3.2 eV or more or 400 nm or less. Thus, when the corresponding photon energy is incident, the energy is absorbed to form an electron hole pair, and the excited holes react with water by a strong oxidative force to generate OH radicals, which decompose the organic material. Done. The reaction process of the photocatalyst is as follows.

    The generated energy of the OH radical is equivalent to 120 Kcal / mol of the organic compound

 Several kinds of C-C bonds, C-H bonds, C-N bonds, C-O bonds, O-H bonds and N-H bonds

It is larger than the binding energy. The photocatalyst thus breaks down this bond. That is, since organic matters can be easily decomposed, they are widely used for the removal and sterilization of contaminants, harmful substances or germs.

    However, the ability to decompose organic matter, which is a characteristic of photocatalysts,

In production it appears to be a big limitation. In other words, by oxidizing organic matter,

Degradation is a disadvantage for producing products. In other words,

The energy generated by the photocatalyst's OH radicals can be found in various ways, including C-C bonds, C-H bonds, C-N bonds, C-O bonds, O-H bonds and N-H bonds.

Since it is larger than the binding energy, when the photocatalyst is coated directly on the plastic

When the photocatalyst comes into contact with the binder, the reaction of oxidizing and decomposing the plastic and the binder

 It occurs, discoloration occurs, the plastic and the photocatalyst is separated and the photocatalytic efficiency is inferior.

In Korea Patent 10-2010-0075850 styrene acrylic copolymer binder (styrene

various polymer materials such as acrylic copolymer binder)

And fixed to the plastic. However, using these polymeric materials as binders

In the prepared photocatalyst plastic, the binder is oxidized and decomposed by the coated photocatalyst after 1 to 3 years. As a result, the photocatalyst-coated plastic and the binder are discolored, thereby decreasing transparency. In addition, the photocatalyst oxidizes the binder to generate space, which causes the photocatalyst to be separated from the binder, the photocatalyst is separated from the plastic, and the photocatalyst properties of the coated photocatalyst are deteriorated.

        In Korean Patent 10-2009-0124425, as a binder of the photocatalyst,

A method for preparing a photocatalyst with methyltrimethoxysilane or methyltriethoxysilane has been proposed. The use of such silicone-based silanes as a binder for photocatalysts does not provide good performance of the photocatalyst because the silanes surround the photocatalysts, and the silanes do not have good adhesion with plastics.

    Korean Patent 10-0330955 describes vinyl esters and / or vinyl ethers.

Fluorinated polymers or silicon-based polymers containing copolymers of fluoroolefins are used as binders. In this case, the site of fluoroolefin contact

It is not decomposed by the photocatalyst. However, photocatalysts are vinyl esters and / or vinyl

Sites in contact with the ether are degraded. That is, such a binder is a single polymer

Although it has better photocatalytic degradation resistance than using a binder, the photocatalyst of the binder

Decomposition is not completely solved. Also with vinyl esters and / or vinyl ethers

Since the binder surrounds the photocatalyst in the fluorinated polymer or the silicon-based polymer containing the copolymer of fluoroolefin, there is a problem in that the efficiency of the photocatalyst is lowered because there is less protruding portion to the outside.

    Korean Patent 2003-0038744 mentions coating a photocatalyst after coating 80 nm SiOC with a primer by CVD deposition. Such a primer of SiOC can protect the surface of the plastic from the photocatalyst and increase the efficiency of the photocatalyst.

However, before coating the photocatalyst, the CVD was performed to coat SiOC with a primer. This treatment requires expensive equipment. So the production cost is high. In addition, the treatment of the primer by CVD requires post-production of the primer in an amorphous form and later crystallization. In addition, the plastic and the primer fall off when bending the photocatalyst-treated plastic due to poor adhesion with the plastic.

    In Japanese Patent Laid-Open No. 9-190514, a titanium precursor is coated on a plastic.

After that, the photocatalyst was fired on the plastic by microwave irradiation. Such

Firing through microwave irradiation can cause the photocatalyst to fire on the plastic at low temperatures.

It has advantages. However, these photocatalysts can be directly

The coating has a problem in that the photocatalyst also oxidizes the surface of the plastic for the same reason as mentioned above, so that the photocatalyst and the plastic are separated, and thus the efficiency of the photocatalyst continues to drop over time.

    As mentioned above products that need to be used at low temperatures, such as plastic

Due to the limitation of the characteristics of oxidizing the polymer material, which is an advantage and disadvantage of the photocatalyst above,

Photocatalyst coated on plastic has no commercialized product due to durability

It is true.

There are several problems to be solved in loading photocatalysts in plastics.

a) Photocatalyst should adhere well with plastic

b) the photocatalyst should not be recessed on the binder so that the photocatalytic activity is not reduced.

c) The photocatalytic activity should not deteriorate plastics by decomposition.

d) The firing temperature of the photocatalyst should be below the heat distortion temperature of the plastic.

e) Photocatalysts should be able to exhibit the performance of photocatalysts in the UV and visible light.

It relates to a method for producing a photocatalyst coated on a plastic according to the present invention. More specifically, it has a two-layered structure in which a primer coating layer of nickel oxide and a coating layer of titanium oxide to which nanoparticles of titanium oxide are added onto a plastic are microwave-fired.

The photocatalyst manufacturing method of coating nickel oxide with a primer on a plastic according to the invention has the following effects.

    The photocatalyst coated on the nickel oxide coated plastic of the two-layer structure according to the present invention is

 Electrons and holes excited by ultraviolet rays and visible light do not recombine with each other,

By contributing to the chemical action, the treatment efficiency is improved by about 2 times or more compared to the conventional.

And it can prevent the plastic from deteriorating due to the photocatalyst. Since the photocatalyst binder is used as the titanium oxide sol, the efficiency of the photocatalyst is high because both the titanium oxide and the titanium oxide binder of the nanoparticles exhibit the effect of the photocatalyst. And since the binder is used as titanium oxide, the efficiency can be prevented by wrapping nano titanium oxide. In addition, since the binder of the nano titanium oxide is composed of anatase and rutile type, the binder is effective not only in ultraviolet light but also in some visible light. By firing the oxide precursor with microwaves, the photocatalyst can be coated without deformation of the plastic.

1 is a view showing the principle of operation of a general photocatalyst
2 is a view showing the structure of a photocatalyst coated on a plastic according to the present invention
Figure 3 is a flow chart showing the manufacturing process of the photocatalyst coated on the plastic according to the present invention
4 is a decomposition reaction measurement result of the photocatalyst coated on the plastic according to the present invention
Showing drawings

The photocatalyst manufacturing method and features coated on the plastic according to the present invention are as follows.

The first step is to prepare a plastic and to clean the surface of the plastic,

Coating a nickel oxide primer on the second step plastic,

The third step is the step of firing the nickel oxide coated on the plastic by microwave,

The fourth step is titanium oxide containing nanoparticles of titanium oxide on the calcined nickel oxide

Coating the precursor

The fifth step consists in firing the titanium oxide precursor layer containing the coated titanium oxide nanoparticles with microwaves.

    The photocatalyst structure coated on the plastic according to the present invention having the characteristics as described above

Referring to the accompanying drawings 2 as follows. First, the concept of the present invention is the structure of the photocatalyst coated on the plastic is titanium oxide (TiO) containing nanoparticles of titanium oxide

 It has a two-layer structure in which a nickel oxide (NiO) coating layer is formed between the coating layer and the plastic.

Improve the efficiency of the photocatalyst, prevent the photocatalyst from oxidizing the plastic,

It has a performance of photocatalyst in visible light.

    3 is a photocatalyst coated on a plastic having a two-layer structure according to the present invention.

The manufacturing method will be described as follows.

    In the first step, the plastic substrate to be coated with the photocatalyst is prepared using alcohol, acetone,

Wash clean with deionized water. In this case, the reason why the plastic should be cleaned is that the adhesion of the oxide coating is deteriorated when there is a foreign matter on the surface of the plastic, and the transparency decreases when there is a foreign matter. In addition, the cleaning operation may be omitted for the continuous operation. The plastics are PE (polyethylene), PP (polypropylene), EVA (polyethylene vinyl acetate), PET (polyethylene terephthalate), PVC (polyvinylchloride), PC (polycarbonate), PMMA (polymethacrylate) ), PI (Polyimide), PBT (Polybutylene Terephthalate), Polyamide, Polyurethane, etc. made of a polymer form is used. In addition, it includes a polymer film and fibers that can be supplied in a continuous roll form, it can be used as a material made of paper, wood, metal and the like.

    In the second step, a nickel oxide sol is made and coated on the plastic. Nickel chloride (NiO) primer is used as nickel chloride. Nickel acetate, Nickel carbonate, Nickel hydroxide, Nickel nitrate, Nickel sulfamate, Nickel sulfate, Nickel citrate and the like can also be used. The nickel oxide coating here shows that the anatase type titanium oxide has a bandgap of 3.2 eV but the nickel oxide has a bandgap of 4.0 eV, so that the photocatalyst coated on the plastic has an electron-hole pair excited by incident light Separation by the difference in energy levels of titanium oxide increases the probability that holes will participate in chemical reactions, thereby improving photocatalytic efficiency by more than two times. Solvents used in steps 2 and 4 include water, methanol, ethanol, isopropanol, 1-methoxypropanol, butanol, ethylhexyl alcohol, terpineol, ethylene glycol, glycerin, ethyl acetate, butyl acetate, and methoxypropyl Acetate, carbitol acetate, ethyl carbitol acetate, methyl cellosolve, butyl cellosolve, diethyl ether, tetrahydrofuran, dioxane, methyl ethyl ketone, acetone, dimethylformamide, 1-methyl-2-pyrroli It is also possible to use any one or more selected from pig, dimethyl sulfoxide, hexane, heptane, paraffin oil, mineral spirit, toluene, xylene, chloroform and acetonitrile. In addition, the method of coating the nickel oxide and titanium oxide precursor on the plastic in the second and fourth steps uses a three-stage roll coating. In addition, the coating, such as spray, three-stage roll coating, comma roll, gravure coating, three-stage roll coating, inkjet coating, knife coating, Meyer bar coating, etc. may use a known coating means or may be used as a special coating method It is not limited.

    The liquid is applied immediately after coating the nickel oxide sol coated on the plastic in the third step

A film of state is obtained. The coated nickel oxide sol is fired in microwave. In this microwave irradiation, since microwaves irradiate the inside and outside of the nickel oxide uniformly, the nickel oxide becomes a uniform temperature rise and the nickel oxide is fired to obtain a solid oxide crystalline coating film. The primer having an inorganic structure irradiated with the microwaves undergoes a hydrolytic condensation reaction between hydrolyzable groups over time during the formation of the coating film, thereby increasing the crosslinking density of the inorganic structure of the resulting coating film and providing a coating film having excellent solvent resistance and the like. Can be formed. This reaction does not affect the substrate when irradiating microwaves to the oxide precursor, and the crosslinking density is further increased to obtain a primer layer excellent in long-term weather resistance. However, since the microwave irradiation does not raise the temperature of the surface of the plastic, the nickel oxide can be fired so that the plastic material does not change. In addition, microwave irradiation provides good adhesion to plastics for nickel oxide. The microwave irradiation apparatus uses microwaves having a bandwidth of 300 MHz to 300 GHz. More preferably, microwaves with a bandwidth of 2.45 GHz are used. A photocatalyst-coated plastic manufacturing method characterized by firing a primer of titanium oxide (NiO) and titanium oxide (TiO) precursor by microwave.

    In the fourth step, a sol of titanium oxide is first made, and nanoparticle titanium oxide is added thereto. The addition of such nanoparticle titanium oxide is for widening the surface area of titanium oxide protruding outward. The larger the surface area protruding to the outside of the photocatalyst, the higher the efficiency of the photocatalyst. In addition, the nanoparticles of titanium oxide are composed of anatase and rutile type mixture. Thus, the rutile titanium oxide containing nanoparticles exhibits a photocatalytic effect even in part of visible light. Here, the nano titanium oxide particles may be a mixture of anatase type and rutile type, or may be used alone or anatase or rutile type.

    Titanium oxide sol containing nanoparticles on nickel oxide coated on plastic in the fifth step

Immediately after coating (sol), a liquid film is obtained. This coated titanium oxide sol

Firing with microwaves. This microwave irradiation shows that the microwave

By uniformly irradiating the inside and the outside, the titanium oxide becomes a uniform temperature rise, and the titanium oxide is calcined to obtain a solid oxide crystalline coating film. However, since the microwave irradiation does not raise the temperature of the surface of the plastic, it is possible to fire the titanium oxide so that the plastic material does not change.

    4 is a decomposition reaction measurement of a two-layered photocatalyst according to the present invention prepared as described above

A graph showing the results: methylorange decomposition, a kind of dyeing wastewater

It is the result evaluated by reaction. It can be seen that the decomposition reaction rate of the titanium oxide coating film containing nickel oxide-titanium oxide nanoparticles, which is a two-layer structure, is significantly improved compared to the photocatalyst coated with only one layer of titanium oxide, nickel oxide coated with a pre-polymer, and titanium oxide coated. have.

none

Claims (5)

A nickel oxide (NiO) primer coating layer formed on a plastic, a method of firing the nickel oxide primer by microwave, a titanium oxide (TiO) coating layer containing titanium oxide (TiO) nanoparticles on the nickel oxide coating layer and titanium oxide nano In the manufacturing method for firing the titanium oxide coating layer containing the particles with a microwave
It has the following work steps.
A first step of preparing and washing the plastic;
Coating a primer of nickel oxide (NiO) on the plastic;
A third step of firing the coated nickel oxide (NiO) primer by microwave
Of titanium oxide (TiO) comprising nanoparticles of titanium oxide on the coated nickel oxide
A fourth step of coating the precursor;
A precursor of titanium oxide (TiO) comprising the nanoparticles of the coated titanium oxide
Photocatalyst comprising the fifth step of firing with microwave
Manufacturing method of coated plastic
The method of claim 1,
In the manufacturing method using nickel oxide (NiO) used in the second step as a primer, the primer layer of nickel oxide (NiO) is preferably niobium oxide (NbO: 3.4 eV), tin oxide (SnO: 3.5 eV), A manufacturing method comprising an oxide semiconductor film containing at least one metal oxide selected from the group consisting of aluminum oxide (AlO:> 5eV), zinc oxide (ZnO: 3.3eV) and zirconium oxide (ZrO: 5.0eV)
The method of claim 1, wherein
Method of manufacturing a method characterized in that the firing of the nickel oxide (NiO) primer and titanium oxide (TiO) precursor by microwave in the third and fifth steps
The method of claim 1,
In the fifth step, the precursor of titanium oxide (TiO) is titanium propoxide (titanium () propoxide), titanium isopropoxide (titanium () isopropoxide), titanium diisopropoxide (titanium () diisopropoxide), titanium butoxide Titanium () butoxide, Titanium () ethooxide, and Titanium (IV) methoopoxide, Titanium tetrachloride, Titanium nitride, Titanium boride, Titanium (IV) oxysulfate, Titanium (IV) sulfide One or more selected from the group consisting of may be used.
The method of claim 1,
In the fourth step, anatase type titanium oxide 80% and rutile type titanium oxide 20%
Titanium oxide nanoparticles consisting of a mixture are used. In addition, anatase or rutile type titanium oxide can also be used here. Also of titanium oxide particles
How to use the size from 1nm to 400nm size.

Example 1
(a) Nickel Oxide Synthesis
To 50 moles of isopropyl alcohol, 0.2 moles of nickel chloride were added and the mixture was heated at 90 degrees for 30 minutes.
Mix. Thereafter, 0.4 mol of distilled water is added, followed by mixing for 30 minutes. this
The coating solution is coated on the polyester film. And 2.45Hz with microwave,
Irradiate at 700 Watts for 10 minutes.
(b) Nanoparticle-containing Titanium Oxide Synthesis
To 50 moles of isopropyl alcohol, add 0.2 moles of isopropyl titanium and mix for 30 minutes.
do. Thereafter, 0.01 mol of hydrochloric acid is added to mix for 30 minutes. Thereafter, 0.8 mol of distilled water is added, followed by mixing for 30 minutes. After adding 5 grams of nanoparticle titanium oxide of 80% anatase type and 20% rutile type, the mixture was mixed for 2 hours. The coating solution is coated on a nickel oxide coated polyester film and irradiated with microwave at 2.45 GHz, 700 Watt, for 10 minutes.

Comparative Example 1
To 50 moles of isopropyl alcohol, add 0.2 moles of isopropyl titanium and mix for 30 minutes.
do. Thereafter, 0.01 mol of hydrochloric acid is added to mix for 30 minutes. Thereafter, 0.8 mol of distilled water is slowly added, followed by mixing for 30 minutes. The coating solution is roll-coated on a nickel oxide coated polyester film and irradiated with microwave at 2.45 Hz at 700 Watts for 10 minutes.

Comparative Example 2
To 50 moles of isopropyl alcohol, 0.2 moles of nickel chloride was added, and at a temperature of 90 degrees for 30 minutes.
Mix. Thereafter, 0.01 mol of hydrochloric acid is added to mix for 30 minutes. Thereafter, 0.8 mol of distilled water is added, followed by mixing for 30 minutes. This coating solution is roll coated on a polyester film. And microwave for 10 minutes at 2.45 GHz, 700 Watts.
Do it.
To 50 moles of isopropyl alcohol, add 0.2 moles of isopropyl titanium and mix for 30 minutes.
do. Thereafter, 0.01 mol of hydrochloric acid is added to mix for 30 minutes. Then distilled water
After adding 0.8 mol, mix for 30 minutes. This coating solution is coated with nickel oxide
10 minutes at 2.45Hz, 700Watt by microwave after roll coating on polyester film
Investigate while

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