KR20110134967A

KR20110134967A - Synthetic wood with thermal barrier and antifouling property and preparation method thereof

Info

Publication number: KR20110134967A
Application number: KR1020100054626A
Authority: KR
Inventors: 김태진; 위유환; 정광희
Original assignee: 뉴엔텍(주)
Priority date: 2010-06-10
Filing date: 2010-06-10
Publication date: 2011-12-16

Abstract

PURPOSE: A synthetic wood with a thermal blocking function and a contamination preventing function and a manufacturing method thereof are provided to block an infrared ray of the sun to prevent a temperature increase, thereby preventing cracks and damage of a synthetic wood due to repetitive expansion and contraction. CONSTITUTION: Titanium dioxide particles are dispersed in a titanium dioxide photo catalyst solution. Titanium alkoxide and silicon alkoxide are hydrolyzed and peptized in liquid to form the titanium dioxide photo catalyst solution. The titanium dioxide photo catalyst solution and antimony tin-oxide are mixed to manufacture a photo catalyst complex coating composition. The photo catalyst complex coating composition is coated on the surface of a synthetic wood.

Description

Synthetic wood with thermal barrier and antifouling property and preparation method

The present invention relates to a synthetic wood having a heat shielding and anti-pollution function, and a method for manufacturing the same, wherein antimony tin oxide particles that block heat (infrared rays) and titanium dioxide particles having a photocatalytic activity to prevent contamination are formed on the surface of the synthetic wood. The coating layer is combined to prevent breakage and deformation due to thermal expansion and contraction of the synthetic wood, and at intervals considering the thermal expansion of the synthetic wood during construction, it solves the problem of unsightly appearance and prevents contamination of the surface of the synthetic wood. Provides synthetic wood.

Natural wood is generally difficult to supply raw materials in view of the weakness of moisture, pests and durability when used as interior materials of buildings and the depletion of wood resources and consequently international nature protection. Preservative wood preservative treated natural wood to replace these natural wood to some extent solved the problems of weak moisture resistance, disease resistance and durability of natural wood through antiseptic treatment, but phthalates, formaldehyde, nonyl Phenolic and arsenic pentoxide are banned due to the environmental and human health problems, and arsenic or quaternary ammonium compounds in use are also eluted in small amounts. Recently, synthetic resins are mixed with wood materials. Are manufactured and supplied actively.

Such synthetic wood is sawdust or wood chips, as well as synthetic resin is put into the mixer at the same time in the form of granules, each of the materials put in the granule form is processed to a predetermined size through the grinding process and then mixed with each other through the heating process. That is, during the heating process, the synthetic resin is mixed with each other through the stirring process, sawdust, wood chips, etc. added with the synthetic resin in the molten and molten state, these mixed materials are manufactured from synthetic wood through the extrusion method It was common to be.

However, such synthetic wood has a higher thermal expansion rate than natural wood, so when it is used for interior and exterior building materials, the damage progresses over time due to repetition of shrinkage and expansion. In order to prevent this, the joint part between the synthetic wood and the synthetic wood is spaced at regular intervals. Since the construction needs to be spaced above, there is a problem that the construction hassle and appearance is not good, and as time passes, the surface of the synthetic wood is contaminated by organic compounds or dust, and thus the contaminated surface is not washed well. .

An object of the present invention is to block the heat supplied to the synthetic wood to prevent damage and deformation due to thermal expansion and contraction of the synthetic wood in advance, there is no need to widen the gap between the synthetic wood during construction, It is to provide a synthetic wood and a method for producing the same that the surface is not contaminated well and washed well even if the surface is contaminated.

Synthetic wood having a thermal barrier and anti-fouling function of the present invention, the photocatalyst comprising an antimony tin oxide particle having an average particle size of 5 to 20 nm, titanium dioxide particles having an average particle size of 5 to 30 nm and a polysiloxane binder on the surface of the synthetic wood. A composite coating layer is formed.

In addition, the method for producing a composite wood having a thermal barrier and anti-fouling function of the present invention comprises the steps of preparing a titanium dioxide photocatalyst solution in which titanium dioxide particles are dispersed by hydrolyzing and bridging titanium alkoxide and silicon alkoxide in a liquid phase in the presence of an acid; Preparing a photocatalyst composite coating composition by mixing the titanium dioxide photocatalyst solution and antimony tin oxide; And applying the photocatalyst composite coating composition to the surface of the synthetic wood.

In the method for producing a composite wood having a thermal barrier and anti-fouling function of the present invention, the step of preparing the titanium dioxide photocatalyst solution is 8-30% by weight of titanium alkoxide, 5-15% by weight of silicon alkoxide, 2-6% by weight of acid and After mixing 50 to 80% by weight of water is characterized in that the heating while stirring for 4 to 10 hours at 50 ~ 80 ℃.

In the method for producing a synthetic wood having a thermal barrier and anti-fouling function of the present invention, the antimony tin oxide is antimony salt and tin so that the molar ratio of antimony and tin to 0.5 to 9.5 to 1.5: 8.5 to 50 to 80% by weight of a basic solution The salt is characterized in that the antimony tin oxide containing solution sintered after mixing 20 to 50% by weight.

In the method for producing a composite wood having a thermal barrier and anti-fouling function of the present invention, the step of preparing the photocatalyst composite coating composition is a mixture of 70 to 90% by weight of the antimony tin oxide containing solution and 10 to 30% by weight of titanium dioxide photocatalyst solution It is characterized by stirring for 3 to 10 hours.

Synthetic wood with heat shielding and pollution prevention function manufactured by the method of the present invention can prevent the temperature rise by blocking the infrared rays of sunlight can prevent cracks, breakage due to repeated expansion and contraction, and during construction You can make the beauty and beauty more easy without the need for spacing. In addition, UV rays can be used to decompose contaminants on the surface of synthetic wood or change the surface of synthetic wood to hydrophilicity to remove contaminants by rainwater. It has the advantage of preventing discoloration.

1 shows the results of X-ray diffraction analysis of the titanium dioxide photocatalyst of Preparation Example 1.
2 is an electron scanning microscope (TEM) photograph of the titanium dioxide photocatalyst of Preparation Example 1. FIG.
Figure 3 shows the X-ray diffraction analysis of the antimony tin oxide of Preparation Example 2.
4 is an electron scanning microscope (SEM) photograph of the antimony tin oxide of Preparation Example 2. FIG.
5 is an methylene blue decomposition photo of glass beads coated with the photocatalytic composite composition of Experimental Example 2.

Synthetic wood having a thermal barrier and anti-fouling function of the present invention, a photocatalyst comprising an antimony tin oxide particle having an average particle size of 5 to 20 nm, titanium dioxide particles having an average particle size of 1 to 30 nm and a polysiloxane binder on the surface of the synthetic wood. The composite coating layer is formed.

The photocatalytic composite coating layer of the present invention comprises an infrared absorbing material. In sunlight, visible light and ultraviolet rays are absorbed by infrared rays and include antimony tin oxide, indium tin oxide, and aluminum zinc oxide, but indium tin oxide Aluminum zinc oxide can be applied to expensive devices such as solar cells and display devices due to the high manufacturing cost, but it is limited in price to be used for synthetic wood, and also antraquione, phthalocyanine, Naphtocyanine-based, Diimmonium-based, and Naphtophthalocyanine-based organic compounds also have the effect of absorbing near-infrared rays. Because of the disadvantage of low transparency, antimony tin oxide is preferable as the infrared absorbing material of the present invention, More preferably, 5-20 nm antimony tin oxide particles are used for infrared absorption.

The photocatalytic composite coating layer of the present invention includes a photocatalyst. Photocatalyst is a semiconductor material that absorbs light beyond the band gap, and electrons and holes are generated on the surface. Water and oxygen abundantly exist around us by electrons (e-) and holes (h +). It is converted into hydroxyl radical (OH ·) or active oxygen (O ₂ ⁻ ) with very high oxidative activity, and these are harmful organic substances such as formaldehyde, volatile organic compounds, odor causing substances, pollutants, environmental hormones, etc. It has a function of oxidizing and decomposing and removing. Materials exhibiting photocatalytic action include various metal oxides and complex oxides such as titanium dioxide (TiO2), zinc oxide (ZnO), tin dioxide (SnO2), nickel oxide (NiO), and iron oxide (Fe2O3), among which titanium dioxide It is preferable at the point of high photocatalytic activity, good acid / alkali resistance, and no harm to a human body. More preferably, the average particle size of titanium dioxide should be 30 nm or less, more preferably 5 to 30 nm, resulting in high photocatalytic activity due to quantum size effect, and improved transparency and dispersibility. In addition, transition metals such as platinum (Pt), rhodium (Rh), tin (Sn), nickel (Ni), copper (Cu) or oxides thereof are added to the titanium dioxide particles to recombine electrons and holes. This disappearance time can be delayed to increase the activity of the photocatalyst.

The photocatalytic composite coating layer of the present invention comprises a polysiloxane binder. The use of a binder is essential for the photocatalyst composite coating layer to be bonded to the synthetic resin surface.

As a binder, organic-based adhesives have good adhesion, but decomposition proceeds due to photocatalytic action. Therefore, inorganic binders such as water glass and silane are mainly used, and fluororesins are relatively stable to photocatalysts, but adhesion is relatively low and expensive.

Water glass or silane-based binders have low adhesion because they are physically bonded, and the binder partially or completely covers titanium dioxide particles, thereby degrading activity because light, water, and oxygen, which are essential for the photocatalytic reaction, do not come into contact with the photocatalytic surface. There is a disadvantage that the substrate can be decomposed by the photocatalyst due to the contact of the material with the photocatalyst. The polysiloxane binder of the present invention is a silicon alkoxide is produced by the hydrolysis and polycondensation reaction is stable to the photocatalyst and chemically reacts with the hydroxyl group on the surface of the synthetic wood to form a bond to form a coating layer having strong adhesion.

Synthetic wood formed on the surface of the photocatalytic composite coating layer of the present invention is selectively absorbed by the antimony tin oxide particles having an average particle size of 5 ~ 20 nm of sunlight and the average particle size 1 ~ 30 nm by the remaining visible and ultraviolet portion Since the photocatalytic activity is expressed in the titanium dioxide particles, the photocatalytic activity is remarkably enhanced as compared with the use of the titanium dioxide particles alone.

Synthetic wood having a thermal barrier and anti-fouling function of the present invention comprises the steps of preparing a titanium dioxide photocatalyst solution in which titanium dioxide particles are dispersed by hydrolyzing and bridging titanium alkoxide and silicon alkoxide in a liquid phase in the presence of an acid; Preparing a photocatalyst composite coating composition by mixing the titanium dioxide photocatalyst solution and antimony tin oxide; And applying the photocatalyst composite coating composition to a surface of synthetic wood.

The preparation step of the titanium dioxide photocatalyst solution of the present invention is a mixture of 8 to 30% by weight of titanium alkoxide, 5 to 15% by weight of silicon alkoxide, 2 to 6% by weight of acid and 50 to 80% by weight of water at 50 to 80 ℃ Heat with stirring for 10 hours. Preferably, 10 to 20% by weight of titanium alkoxide, 7 to 12% by weight of silicon alkoxide, 3 to 4% by weight of acid and 70 to 80% by weight of water are mixed and then heated at 60 to 80 ° C. with stirring for 6 to 8 hours. The titanium alkoxide, silicon alkoxide, acid and water are mixed, and the titanium alkoxide and silicon alkoxide are reacted with water and acid through hydrolysis and peptization by heating while stirring. The titanium alkoxide has a particle size of 30 Anatase-type titanium dioxide particles of less than or equal to nm were prepared, and at the same time, silicon alkoxide hydrolysis and polycondensation reaction were carried out to be converted to polysiloxane, and a titanium dioxide photocatalyst solution containing polysiloxane was added to the surface of the synthetic wood without addition of a binder. It also acts as a binder.

The titanium alkoxide is titanium propoxide, titanium isopropoxide or titanium buthoxide, and silicon alkoxide is silicon ethoxide.

The acid is also nitric acid (HNO 3), hydrochloric acid (HCl), sulfuric acid (H 2 SO 4), paratoluenesulfonic acid or acetic acid (CH 3 COOH), preferably nitric acid, and the water is preferably deionized water.

The antimony tin oxide of the present invention is a sintered antimony tin oxide after mixing 20-50 wt% of the antimony salt and tin salt in a 50 to 80% by weight of the basic solution to the molar ratio of antimony and tin to 0.5: 9.5 to 1.5: 8.5 Preference is given to using oxide containing solutions.

As the solvent of the antimony tin oxide-containing solution, water or an organic solvent may be used alone, or a mixture of boiling points different from each other may be used. Examples of the organic solvent include alcohols such as methanol, ethanol, isopropanol, butanol, 1,2-butanediol, 1,4-butanediol, ketones such as methyl ethyl ketone, isobutyl ketone and methyl isobutyl ketone, benzene, toluene, xylene and the like. Benzenes may be used. The solvent is added to the basic solution adjusted to pH 9-12, preferably 10-11, by adding antimony salt and tin salt, followed by sintering at 200-500 ° C.

In preparing the photocatalytic composite coating composition of the present invention, 70 to 90 wt% of the antimony tin oxide-containing solution and 10 to 30 wt% of the titanium dioxide photocatalyst solution are mixed and stirred for 3 to 10 hours.

The photocatalyst composite coating composition prepared above is coated on the surface of the synthetic wood and dried to prepare a synthetic wood having a heat shielding and pollution prevention function of the present invention. Synthetic wood of the present invention is a photocatalyst composite coating layer comprising a surface of the antimony tin oxide particles having an average particle size of 5 ~ 20 nm, titanium dioxide particles having an average particle size of 1 ~ 30 nm and a polysiloxane binder.

Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples and Preparation Examples. The following examples are only illustrative for the purpose of illustrating the present invention, and the scope of the technical spirit of the present invention is not limited thereto.

Preparation Example 1 Preparation of Titanium Dioxide Photocatalyst Solution

Anatase type titanium dioxide photocatalyst solution in which polysiloxane is formed as a binder by mixing 80 g of titanium isopropoxide, 50 g of silicon ethoxide and 20 g of nitric acid for 6-8 hours at a temperature of 60-80 ° C. in 400 ml of distilled water. Was prepared.

When the titanium dioxide photocatalyst solution was dried and subjected to X-ray diffraction analysis, it was found that a photocatalyst having excellent activity as an anatase titanium dioxide crystal structure was prepared (FIG. 1).

The particle size and shape of the titanium dioxide contained in the titanium dioxide photocatalyst solution were investigated using an electron scanning microscope (TEM). Particle size of the prepared photocatalyst was about 25 -30 nm, it was irradiated in an elliptical form (Fig. 2).

Preparation Example 2 Preparation of Antimony Tin Oxide Solution

300 ml of distilled water and 300 ml of 1,4-butanediol were adjusted to pH 11 using caustic soda. A solution of 375 g of tin tetrachloride (SnCl 4 · 5H 2 O) and 25 g of antimony trichloride (SbCl 3) was added to an ultrasonic cleaner for 2 hours, and ultrasonically applied to make a white colloidal solution sufficiently dispersed. The white colloidal mixture thus prepared was placed in a autoclave and heated at a rate of 5 ° C./min to 300 ° C. in a nitrogen atmosphere for crystallization, and then maintained for 4 hours to prepare an antimony tin oxide-containing solution.

The antimony tin oxide-containing solution was dried and subjected to X-ray diffraction analysis. As a result, peaks representing the (110), (101), (200), (211), and (301) planes were found in JCPDS card NO. Consistent with the results of 72-1147, it was investigated that pure tin oxide was prepared (FIG. 3).

The particle size and shape of the antimony tin oxide were investigated by using an electron scanning microscope (SEM). The particle size of the prepared antimony tin oxide was 5 ~ 20 nm or less, it was irradiated in the spherical form (Fig. 4).

Preparation Example 3 Preparation of Photocatalyst Composite Coating Composition

30 g of the titanium dioxide photocatalyst solution of Preparation Example 1 and 70 g of the antimony tin oxide containing solution of Preparation Example 2 were mixed and sufficiently stirred for 5 hours to prepare a photocatalyst composite coating composition.

Example 1:

The photocatalyst composite coating composition of Preparation Example 3 was coated on the composite wood of 2 cm × 10 cm × 100 cm using a high volume low pressure, and the coating was performed twice in total, once in the width direction, and at the room temperature. Drying over time to prepare a synthetic wood having a photocatalytic composite coating layer formed. The thickness of the photocatalyst composite coating layer coating film was 5 μm.

Comparative Example 1:

Titanium dioxide photocatalyst solution of Preparation Example 1 was coated on synthetic wood of 2 cm × 10 cm × 100 cm using a high volume low pressure, once in a horizontal direction and a total of two times, and at room temperature Drying over time to prepare a synthetic wood having a photocatalyst coating layer. The thickness of the photocatalyst coating layer coating film was 2 μm.

Experimental Example 1: Thermal Cutoff Effect

After preparing five dried specimens by coating the photocatalyst composite coating composition prepared in Preparation Example 3 on a glass plate, a thermal cut test was conducted using a Solar Transmission & BTU Power Meter, and summarized in Table 1 below.

Number of tests Thermal cutoff rate (%) One 72 2 71 3 68 4 71 5 69

The difference in the thermal barrier rate of the test result was judged to be due to the throughput of the photocatalytic composite coating composition coated on the glass surface because of the human coating, and the thermal barrier rate was about 70%.

Experimental Example 2: Methylene Blue Degradation Effect

The photocatalyst composite coating composition prepared in Preparation Example 3 was coated on glass beads and dried, and then a methylene blue decomposition experiment was performed to investigate the degradation activity of the contaminants. 20 ml of 20 ppm methylene blue solution was poured into each of two sares, and then, glass beads coated with a photocatalytic composite coating composition and 20 g of pure glass beads, respectively, were added thereto and exposed to sunlight. After 6 hours, methylene blue of pure glass beads remained blue (left of FIG. 5), but methylene blue was decomposed and changed to colorless in glass beads coated with the photocatalytic composite coating composition (right of FIG. 5). .

Experimental Example 3 Formaldehyde Degradation Effect

In a 1 L container, a 10 × 10 cm glass plate coated with a photocatalyst in Preparation Example 3 and 2 μl of formaldehyde were injected, and 20 W black light was irradiated, and the content of formaldehyde was measured by a gas detection tube method. Two hours after the start of the test, formaldehyde was removed 83%.

Experimental Example 4: Evaluation of Hydrophilicity

The hydrophilicity evaluation of the synthetic wood coated with the photocatalytic composite composition prepared in Example 1 and the synthetic wood not coated with any material (Comparative Example 2) was carried out. Distilled water was put in a syringe and dropped on the synthetic wood of Comparative Example 2, and the contact angle between the synthetic wood and the water droplet was measured by a microscope. The contact angle of the synthetic wood of Example 1 coated with the photocatalytic composite composition was 9 degrees, indicating high hydrophilicity. It appeared to be visible and maintained after 200 hours.

Experimental Example 5 Evaluation of Thermal Expansion Rate

The length of the thermally expanded synthetic wood (mm) was measured after exposure to 100 hours of synthetic wood with a length of 100 cm when stored for 12 hours in a state where sunlight was blocked.

division Inflated length (mm) Example 1 0.7 Comparative Example 1 3.4 Comparative Example 2 3.6

Although the composite wood of Comparative Example 2 which was coated only with the non-coated Synthetic Wood or the titanium dioxide photocatalyst solution could not inhibit thermal expansion, the composite wood coated with the photocatalytic composite composition of the present invention had a significantly higher thermal expansion rate. It was confirmed that the decrease.

Claims

Synthetic wood having a thermal barrier and anti-fouling function formed on the surface of the composite wood, a photocatalytic composite coating layer comprising an antimony tin oxide particle having an average particle size of 5 to 20 nm, titanium dioxide particles having an average particle size of 5 to 30 nm, and a polysiloxane binder.

Preparing a titanium dioxide photocatalyst solution in which titanium dioxide particles are dispersed by hydrolyzing and peptizing titanium alkoxide and silicon alkoxide in a liquid phase in the presence of an acid;
Preparing a photocatalyst composite coating composition by mixing the titanium dioxide photocatalyst solution and antimony tin oxide; And
Method of manufacturing a synthetic wood having a thermal barrier and anti-fouling function comprising the step of applying the photocatalyst composite coating composition on the surface of the synthetic wood.

The method of claim 2, wherein the preparing of the titanium dioxide photocatalyst solution is performed by mixing titanium alkoxide 8-30 wt%, silicon alkoxide 5-15 wt%, acid 2-6 wt% and water 50-80 wt%. Method of producing a synthetic wood having a heat shield and anti-fouling function, characterized in that the heating while stirring at 80 ℃ 4 to 10 hours.

The antimony tin oxide according to claim 2, wherein the antimony tin oxide is mixed with 20-50 wt% of the antimony salt and the tin salt such that the molar ratio of antimony and tin is 0.5: 9.5-1.5: 8.5 to the basic solution of 50-80 wt%. A method for producing a composite wood having a heat shielding and antifouling function, which is a sintered antimony tin oxide containing solution.

The method of claim 4, wherein the preparing of the photocatalyst composite coating composition comprises mixing 70 to 90 wt% of an antimony tin oxide-containing solution and 10 to 30 wt% of a titanium dioxide photocatalyst solution, and then stirring the train for 3 to 10 hours. However, and a method for producing a synthetic wood having a pollution prevention function.