JPH0994525A - Wood product of ultraviolet radiation resistance and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparency for realizing a good hand of wood and apply a building construction at normal temperature and an ultraviolet sealing by specifying respectively the diameters of fine particles and the content of nitrogen when an SiO2 film containing ultrafine particles of ZnO and TiO2 and also nitrogen is formed on a wood surface or a coated wood surface. SOLUTION: An SiO2 film containing ZnO and/or TiO2 ultrafine particles having average particles diameters of 0.005-0.1μm and nitrogen of 0.005-5% based on the atomic percentage is formed and on a wood surface or a coated wood surface. A composition formed by adding the ZnO and TiO2 ultrafine particles to a coating solution mainly composed of a polysilazane having number - average molecular weight of 1,000,000-50,000 and a main skeleton composed of a unit represented by the formula is applied to the wood surface and turned into ceramic to form the SiO2 film. In the formula, R<1> -R<3> represent respectively independent hydrogen atom, an alkyl, an alkenyl, a cycloalkyl, an aryl or groups other than these in which groups connected directly to silicon atoms are carbon atoms, an alkylsilyl, an alkylamino or an alkoxy and one of R<1> -R<3> is hydrogen atom.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to UV resistant wood products. More specifically, the present invention relates to a UV-resistant wood product obtained by making a coating composition containing polysilazane and ceramics ultrafine particles into a ceramic on a wood surface or a painted wood surface, and a method for producing the same.

[0002]

2. Description of the Related Art Wood is the state of the substrate surface (grain, grain,
In order to make the best use of the heather and to make it look more beautiful, transparent painting and colored painting are applied. However, a transparent coating film or a colored coating film applied outdoors is deteriorated and discolored by ultraviolet rays, and its aesthetics cannot be maintained for one year. In addition, there is a problem that it is vulnerable to impact, and its use is limited. A coating composition for imparting UV resistance to wood is disclosed in Japanese Patent Application Laid-Open No. Sho 5
9-135261 describes compositions based on specific alkyd resins.

[0003]

However, the above-mentioned alkyd resin is UV-cut by mixing a pigment, is not transparent, and does not bring out the texture of wood. An object of the present invention is to provide a wood product which is transparent and can make use of the texture of wood, can be applied at room temperature, can block ultraviolet rays, and can impart strength, and is provided with a coating suitable for preventing deterioration of wood. To provide.

[0004]

In order to achieve the above object, the present invention provides: (1) ZnO having an average particle size of 0.005 to 0.1 μm and / or
Another object of the present invention is to provide a UV-resistant wood product characterized by having a SiO ₂ film containing ultrafine particles of TiO ₂ and containing 0.005 to 5% of nitrogen in atomic percentage on the wood surface or painted wood surface. The present invention also includes (2) predominantly the general formula (I):

[0005]

Embedded image

(However, R ¹ , R ² , and R ³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a group other than these groups in which the group directly bonded to silicon is carbon. Represents an alkylsilyl group, an alkylamino group, and an alkoxy group, provided that R ¹ ,
At least one of R ² and R ³ is a hydrogen atom.) A coating solution mainly composed of polysilazane having a main skeleton composed of units represented by the following formula and having a number average molecular weight of 100 to 50,000 has an average particle size of 0.005. A UV-resistant wood product, characterized by applying a coating composition to which ZnO and / or TiO ₂ ultrafine particles of 0.1 μm to 0.1 μm are applied to a wood surface or a painted wood surface to make the composition a ceramic. A method of manufacturing the same is also provided.

The preferred embodiments of the present invention will be listed below. (3) The polysilazane is a perhydropolysilazane having a number average molecular weight of 200 to 10,000 (that is, R in the above formula (I)).
¹ = R ² = R ³ = H), and the UV resistant wood product of (1). (4) The average particle size of ZnO and / or TiO ₂ is 0.05.
(1) UV resistant wood products having a size of not more than μm.

(5) Polysilazane has a number average molecular weight of 2
Method for producing 00-10000 perhydropolysilazane is (that is, when the ^{R 1 = R 2 = R 3} = H in the formula (I)) (2). (6) The average particle size of ZnO and / or TiO ₂ is 0.05
The manufacturing method of (2) which is less than or equal to μm.

By making the filler ultrafine particles having an average particle size of 0.1 μm or less, more preferably 0.05 μm or less, visible light can be transmitted, and by selecting ZnO or TiO ₂ as ceramics, polysilazane can be obtained. Since it has excellent compatibility with, it is possible to obtain a desired dense, hard, and transparent ceramic film, and this ceramic coating film can easily be made a thick film of about 10 μm, and also has an ultraviolet (UV) absorption property. Since it is provided, it can be used as an ultraviolet absorbing transparent ceramic film.

It is difficult to obtain ultrafine ceramic particles having a small average particle diameter, and it is difficult to obtain a transparent ceramic film if the average particle diameter is large.
The lower limit of the average particle size of the ceramic ultrafine particles used is 0.
It is 005 μm, and preferably 0.01 μm. The upper limit is 0.1 μm, preferably 0.05 μm.

The effects of the present invention were obtained by using ultrafine ceramic particles of ZnO and TiO ₂ . Zn
O and TiO ₂ can be used as a mixture. Specifically, for example, Sumitomo Cement's ZnO dispersion ZS303 (particle size 0.
025 μm, 30 wt%, toluene solution) or TiO ₂ powder IT-UD (particle size 0.02 μm, high dispersion treatment type) manufactured by Idemitsu Kosan is preferable. In this case, it may be added to the xylene solution of silazane and appropriately stirred or ultrasonically dispersed, or dispersed by a ball mill. In addition, ZnO powder C-30 manufactured by Mitsubishi Materials and ZnO powder FINEX- manufactured by Sakai Kogyo Co., Ltd.
25, 50, 75 can be used. In this case, in order to disperse the agglomerated particles, a ball mill, a vibration mill,
Powerful processing by paint shaker, attritor, etc. is required. A dispersant may be added as appropriate.

The polysilazane to be used may be any polysilazane having at least a Si--H bond or an N--H bond in the molecule. Not only polysilazane alone but also a copolymer of polysilazane and another polymer or polysilazane and other It can also be used as a mixture with the compound of.

The polysilazanes to be used include those having a chain structure, a cyclic structure, or a crosslinked structure, or those having a plurality of these structures simultaneously in the molecule, and these can be used alone or in a mixture. The following are typical examples of polysilazane to be used, but the polysilazane is not limited thereto. Perhydropolysilazane is preferable from the viewpoint of hardness of the ceramic film.

The ^one having hydrogen atoms in R ¹ , R ² and R ³ in the general formula (I) is perhydropolysilazane,
The manufacturing method is described, for example, in Japanese Examined Patent Publication No. 63-16325, D.
Seyferth et al. Communication of Am. Cer. Soc., C-13,
Reported in January 1983. What is obtained by these methods is a mixture of polymers having various structures, but basically contains a chain portion and a cyclic portion in the molecule,

[0015]

Embedded image

It can be represented by the chemical formula: An example of the structure of perhydropolysilazane is as follows.

[0017]

Embedded image

In the general formula (I), R ¹ and R ² are hydrogen atoms,
A method for producing a polysilazane having a methyl group at R ³ is described in D.
Seyferth et al. Polym. Prepr., Am. Chem. Soc., Div. Po.
lym. Chem., 25 , 10 (1984). The polysilazane obtained by this method has a repeating unit of-
It is a chain polymer and a cyclic polymer of (SiH ₂ NCH ₃ ) —, and neither has a crosslinked structure.

In the general formula (I), R ¹ and R ³ are hydrogen atoms,
A method for producing a polyorgano (hydro) silazane having an organic group at R ² is described in D. Seyferth et al., Polym. Prepr., Am. Chem.
Soc., Div. Polym. Chem., 25 , 10 (1984), JP-A-6
It is reported in JP-A-1-89230 and JP-A-62-156135. The polysilazanes obtained by these methods include those having a cyclic structure with a degree of polymerization of 3 to 5 using-(R ² SiHNH)-as a repeating unit, and (R ³ SiHNH) _x [(R ² SiH) _1.5 N ]
_Some have the chain structure and the ring structure at the same time in the molecule represented by the chemical formula of _1-X (0.4 <x <1).

In formula (I), polysilazane having a hydrogen atom at R ¹ and an organic group at R ² and R ³ , and R ¹ and R ²
An organic group for R ³ and a hydrogen atom for R ³ is — (R ¹ R ²
SiNR ³ ) -is a repeating unit and the degree of polymerization is mainly 3
It has a cyclic structure of ~ 5. The polysilazane used is
As described above, it has a main skeleton composed of the unit represented by the general formula (I), but the unit represented by the general formula (I) may be cyclized as is clear from the above. When the moiety serves as a terminal group and such cyclization does not occur, the terminal end of the main skeleton can be a group similar to R ¹ , R ² or R ³ or hydrogen.

Among the polyorgano (hydro) silazanes are D. Seyferth et al. Communication of Am. Cer. Soc., C.
-132, July 1984. Some have a crosslinked structure in the molecule. An example is as follows.

[0022]

Embedded image

Further, it was reported in JP-A-49-69717.
R like¹SiX_ThreeAmmoni of (X: halogen)
A polysilazane having a cross-linked structure obtained by decomposition
(R ¹Si (NH)_X) Or R¹SiX_ThreeAnd R
² ₂SiX₂Obtained by co-ammonia decomposition of
Use of structured polysilazanes as starting materials
Can be.

[0024]

[Chemical 6]

Further, a polymetallosilazane containing a metal atom as shown in the following structure (in the formula, M which is a side chain metal atom may be crosslinked) can also be used as a starting material.

[0026]

[Chemical 7]

In addition, the repeating unit as reported in JP-A-62-195024 is [(SiH ₂ )
_n (NH) _m ] and [(SiH ₂ ) _r O] (wherein n, m and r are 1, 2 or 3, respectively), polysiloxazane described in JP-A-2-84437. Polyborosilazanes having excellent heat resistance, which are produced by reacting a polysilazane with a boron compound as reported, are reported in JP-A-63-81122, JP-A-63-191832, and JP-A-2-77427. Polymetallosilazanes produced by reacting such polysilazanes with metal alkoxides, JP-A-1-138108 and 1-1.
38107, 1-203429, 1-2034
No. 30, No. 4-63833, No. 3-320167, increased molecular weight (former 4 of the above publication), improved hydrolysis resistance (former 2), inorganic. High silazane polymer and modified polysilazane, JP-A-2-1
No. 75726, No. 5-86200, No. 5-33129.
No. 3 and No. 3-31326, a copolymerized silazane which is advantageous for thickening a film by introducing an organic component into polysilazane, JP-A-5-238827, and Japanese Patent Application No. 4-272.
No. 020, No. 5-93275, No. 5-214268.
No. 5,30,750, and No. 5,338,524, polysilazane can be applied to a metal such as plastics or aluminum in which a catalytic compound for promoting ceramization is added or added. Similarly, low temperature curing type polysilazane which is made into ceramics at a lower temperature can be used.

In the present invention, the following low temperature ceramized polysilazanes can be used. For example, a silicon alkoxide-added polysilazane described in Japanese Patent Application No. 4-39595 by the applicant of the present application may be mentioned. This modified polysilazane has the following general formula (II): Si (OR ⁴ ) ₄ (II) (wherein R ⁴ may be the same or different, Hydrogen atom, an alkyl group having 1 to 20 carbon atoms or an aryl group, wherein at least one R ⁴ is the above alkyl group or aryl group) obtained by heating and reacting with a silicon alkoxide. It is a silicon alkoxide-added polysilazane having an alkoxide-derived silicon / polysilazane-derived silicon atomic ratio in the range of 0.001 to 3 and a number average molecular weight of about 200 to 500,000.

Another example of the low temperature ceramic polysilazane is glycidol-added polysilazane described in Japanese Patent Application Laid-Open No. 6-122852 by the present applicant. The modified polysilazane obtained by reacting the polysilazane represented by the general formula (I) with glycidol has a glycidol / polysilazane weight ratio of 0.001.
And a glycidol-added polysilazane having a number average molecular weight of about 200,000 to 500,000.

As yet another example of the low temperature ceramic polysilazane, Japanese Patent Application No. 5-35604 filed by the present applicant.
The acetylacetonato complex-added polysilazanes described in the above specification are included. This modified polysilazane is
An acetylacetonato complex / polysilazane weight ratio obtained by reacting the polysilazane represented by the general formula (I) with an acetylacetonato complex containing nickel, platinum, palladium or aluminum as a metal is 0.0000.
It is an acetylacetonato complex-added polysilazane having a number average molecular weight in the range of 01 to 2 and about 200 to 500,000. The metal-containing acetylacetonate complex is a complex in which an anion acac ⁻ generated by acid dissociation from acetylacetone (2,4-pentadione) is coordinated to a metal atom, and generally has the formula (CH ₃ COCHCOCH ₃ ) _n M [Wherein, M represents an n-valent metal].

As yet another example of a suitable low temperature ceramized polysilazane, the applicant of the present application, JP-A-6-299.
The metal carboxylate-added polysilazanes described in JP-A-118 are mentioned. This modified polysilazane comprises polysilazane represented by the general formula (I), nickel,
Titanium, platinum, rhodium, cobalt, iron, ruthenium,
The metal carboxylate / polysilazane weight ratio obtained by reacting a metal carboxylate containing at least one metal selected from the group consisting of osmium, palladium, iridium and aluminum is in the range of 0.000001 to 2 and It is a metal carboxylate-added polysilazane having a number average molecular weight of about 200,000 to 500,000. This metal carboxylate is a compound represented by the formula (RCOO) _n M, in which R represents an aliphatic group or alicyclic group having 1 to 22 carbon atoms, and M represents the above metal. .

If the molecular weight of the polysilazane used is too small, the yield upon firing will be low, which is not practical. On the other hand, if the molecular weight is too large, the stability of the solution is low and a sound film cannot be obtained. For these reasons, the molecular weight of the polysilazane used is a number average molecular weight with a lower limit of 100 and preferably 500. The upper limit is 50,000, and preferably 10,000.

There is no effect if the addition amount of the ceramic ultrafine particles is small, and the lower limit of the addition amount of the ceramic ultrafine particles is 5
Parts by weight, preferably 15 parts by weight. On the other hand, if the amount is too large, voids are formed in the film, so the upper limit is 95.
Parts by weight, preferably 85 parts by weight. However, the total weight of polysilazane and ceramic ultrafine particles is 1
00 parts by weight.

The ceramic ultrafine particles should be uniformly dispersed in the polysilazane coating solution. As a method for uniformly dispersing, a high dispersion type (ZS-303,
In the case of IT-UD, etc., it is sufficient to carry out appropriate stirring, ultrasonic dispersion, and ball mill dispersion, but general ceramic ultrafine particles (C-30, F1NEX-29, 5).
In the case of (0,75, etc.), it is necessary to perform a strong dispersion treatment with a ball mill, a vibration mill, a paint shaker, an attritor, etc. in a silazane solution to which a commercially available dispersant has been added, if necessary, to obtain a uniform coating liquid. There is.

Examples of the solvent include aliphatic hydrocarbons, alicyclic hydrocarbons, hydrocarbon solvents of aromatic hydrocarbons, halogenated hydrocarbons such as halogenated methane, halogenated ethane and halogenated benzene, ketones, and aliphatic hydrocarbons. Ethers such as ether and alicyclic ether, and esters can be used.
Preferred solvents are methylene chloride, chloroform, carbon tetrachloride, bromoform, ethylene chloride, ethylidene chloride,
Halogenated hydrocarbons such as trichloroethane and tetrachloroethane, ethers such as ethyl ether, isopropyl ether, ethyl butyl ether, butyl ether, 1,2-dioxyethane, dioxane, dimethyldioxane, tetrahydrofuran, tetrahydropyran, cellosolve acetate, carbitol acetate, pentane Hexane, isohexane, methylpentane, heptane,
Hydrocarbons such as isoheptane, octane, isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, ethylbenzene, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2- Ketones such as heptanone, 4-heptanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, mesityl oxide, phorone, isophorone, methyl acetate, ethyl acetate, n-propyl acetate,
I-propyl acetate, n-butyl acetate, i-butyl acetate,
N-amyl acetate, i-amyl acetate, n-hexyl acetate,
Acetates such as i-hexyl acetate, cyclohexyl acetate and phenyl acetate, and similar propionates,
Butyric acid esters, valeric acid esters, dimethyl maleate, dimethyl malonate, dimethyl oxalate, diethyl oxalate, dimethyl phthalate, diethyl phthalate, and the like.

In the case of using these solvents, two or more kinds of solvents may be mixed in order to adjust the solubility of polysilazane and the evaporation rate of the solvent. The amount (ratio) of the solvent used is selected according to the coating method used so as to improve workability, and is also selected according to the required film thickness, and also depends on the average molecular weight of polysilazane, the molecular weight distribution and its structure. Can be mixed up to about 99% by weight, and preferably has a solid content concentration of 3 to 50.
It is possible to mix in the range of% by weight.

In the coating composition, if necessary, a filler dispersant, a leveling agent, an antifoaming agent, an antistatic agent, a pH adjusting agent, a surface modifier, a plasticizer, a drying accelerator, and a flow stop agent. May be added. The coating composition as described above is repeatedly applied to wood once or twice or more, and then a coating film made of silicon-nitrogen-oxygen system or silicon-nitrogen-oxygen-carbon system ceramic is formed.

The wood to which the coating composition is applied is not particularly limited and includes plywood, chipboard, softboard, hardboard and the like. The wood applied according to the present invention may be applied with a transparent coating or colored coating, or may not be applied. Further, there is no limitation on the shape of these woods, and it is possible to take a plate shape, a square shape, a hollow shape, and other complicated shapes. Those skilled in the art can appropriately select a method suitable for the shape of wood from the coating methods described below.

As a coating means for coating,
Usual application methods such as spin coating, dipping, roll coating, bar coating, brush coating, spray coating, and flow coating are used. In addition, for the adjustment of the base material of the wood before coating, as in the case of conventional coating, drying-removal of adhered contaminants-polishing-knotting-hole filling, etc. are sufficiently performed.

After coating by such a method and drying, the polysilazane containing ultrafine ceramic particles is cured by crosslinking, condensation, oxidation, hydrolysis by accelerating ceramization or sufficiently aging,
Forms a tough coating.

As for the conditions for promoting ceramization, since the working temperature is limited in the case of wood, polysilazane of the type that ceramizes at lower temperatures is used. Construction temperature is room temperature ~
It can be 180 ° C. The atmosphere may be oxygen, air, or an inert gas, but the air is more preferable. The low temperature ceramic type polysilazane has a Si—O bond or S at the low temperature as described above.
A tough coating mainly composed of i-N bonds can be formed. Since this SiO ₂ film is derived from polysilazane, it contains nitrogen in an atomic percentage of 0.005 to 5%.

When low-temperature ceramized polysilazane is used, after coating by the above method,
The heat treatment is performed at a temperature that does not damage the wood, preferably 150 ° C or lower. Generally, when the heat treatment is performed at 150 ° C. or higher, the properties of the wood are deteriorated, such as the wood being deformed and its strength being deteriorated. This heat treatment temperature can be appropriately set by those skilled in the art depending on the type of wood. The heating atmosphere may be either oxygen or air.

In the heat treatment at the above temperature, Si-
A film containing O, Si-N, Si-H, and N-H is formed. This film is still incompletely converted to ceramics. The film can be converted to ceramics by either or both of the two methods described below.

The treatment (aging) pressure in a humidified atmosphere is not particularly limited, but 1 to 3 atm is practically appropriate. The relative humidity is not particularly limited, but 30 to 100% RH is preferable. The temperature is effective at room temperature or higher, but is preferably room temperature to 120 ° C. Aging time is not particularly limited, but is 10 minutes to 30 minutes.
The day is realistically appropriate. By heat treatment in a humidified atmosphere, oxidation of low-temperature ceramic polysilazane or hydrolysis with water vapor proceeds, so that a dense film substantially composed of SiO ₂ can be formed at the low aging temperature as described above. . However, since this SiO ₂ film is derived from polysilazane, it contains 0.005 to 5% of nitrogen in atomic percentage. When the nitrogen content is more than 5%, the film is not sufficiently made into ceramics, and the desired effects (for example, ultraviolet ray prevention property and hardness) cannot be obtained. On the other hand, the nitrogen content is 0.00
It is difficult to make it less than 5%. The preferred nitrogen content is 0.1 to 3% in atomic percent.

Immerse in distilled water containing the catalyst. The catalyst is preferably an acid or a base, and the type thereof is not particularly limited, but examples thereof include triethylamine, diethylamine, monoethanolamine, diethanolamine,
Triethanolamine, n-exylamine, n-butylamine, di-n-butylamine, tri-n-butylamine, guanidine, piguanine, imidazole, 1,8
-Diazabicyclo- [5,4,0] -7-undecene,
Amines such as 1,4-diazabicyclo- [2,2,2] -octane; alkalis such as sodium hydroxide, potassium hydroxide, lithium hydroxide, pyridine, aqueous ammonia;
Inorganic acids such as phosphoric acid; lower monocarboxylic acids such as glacial acetic acid, acetic anhydride, propionic acid, propionic anhydride, or their anhydrides, lower dicarboxylic acids such as oxalic acid, fumaric acid, maleic acid, succinic acid or Anhydrides, organic acids such as trichloroacetic acid; perchloric acid, hydrochloric acid, nitric acid, sulfuric acid,
Sulfonic acid, paratoluenesulfonic acid, boron trifluoride and its complexes with electric donors, etc .; SnCl ₄ , ZnC
l ₂ , FeCl ₃ , AlCl ₃ , SbCl ₃ , TiCl
A Lewis acid such as ₄ and a complex thereof can be used. The preferred catalyst is hydrochloric acid. The content ratio of the catalyst is 0.01 to 50% by weight, preferably 1 to 10% by weight. The holding temperature is effective from room temperature to the boiling point. The holding time is not particularly limited, but 10 minutes to 30 days is practically appropriate.

By immersing the catalyst in distilled water containing a catalyst, the oxidation of the low temperature ceramized polysilazane or the hydrolysis with water is further accelerated by the presence of the catalyst, and at a low heating temperature as described above, substantially SiO ₂ It is possible to form a dense film of However, as described above, since this SiO ₂ film is derived from polysilazane, it also contains nitrogen in an atomic percentage of 0.005 to 5%.

In the present invention, Japanese Patent Application No. 6-
It is also possible to employ the ceramification method described in the specification of No. 236881. According to this method, the composition containing polysilazane is applied to wood, dried sufficiently, and then the coating solution is brought into contact with a mixed solution containing alkoxysilane and water (for example, by a dipping method or a spraying method) at room temperature. In the case of polysilazane also becomes a ceramic, and substantially SiO
_A dense film consisting of ₂ is obtained. This Japanese Patent Application No. 6-236
The alkoxysilane used in the method described in Japanese Patent No. 881 can be arbitrarily selected from the alkoxysilanes generally used for forming a SiO ₂ ceramic coating by a sol-gel method.

Suitable alkoxysilanes are Si (OR)
₄ [wherein each R independently represents an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkylamino group or an alkylsilyl group]. Preferred R is a methyl group, an ethyl group, a propyl group, a butyl group and an isopropenyl group. Among them, particularly preferred alkoxysilanes are tetramethoxysilane and tetraethoxysilane.

[0049] In this method, in addition to the above-mentioned alkoxysilane, in _{R 'n Si (OR) 4} -n [wherein, R each independently represents an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkylamino Group or an alkylsilyl group, R'independently represents a vinyl group, an epoxy group, an amino group, a methacryl group or a mercapto group in addition to the above R, and n is an integer of 1 to 2]. organoalkoxysilane represented, or _{R 'n (RO) 3-} n Si-
R ″ -Si (OR) _3-m R ′ _m [wherein each R independently represents an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkylamino group or an alkylsilyl group, and R ′ is , Each independently represents a vinyl group, an epoxy group, an amino group, a methacryl group or a mercapto group in addition to the above R, R ″ represents a divalent organic bonding group or —O—, and n is 0 to 3, m represents an integer of 0 to 3, provided that n
+ M is 4 or less] may be used. Those skilled in the art can appropriately select such organic groups R ′ and R ″ so that the final ceramic film obtained has a desired film quality (for example, moisture barrier property, oxygen barrier property). You can

Water (H) used in the reactive mixed solution
₂ O) includes ordinary ion-exchanged water, industrial water, filtered water,
Etc. can be used. However, it is preferable to use pure water in consideration of the film quality and the like of the obtained final ceramic coating. It is also possible to use hydrogen peroxide solution instead of water. The content ratio of alkoxysilane and water in the mixed solution is, based on volume, alkoxysilane / water = 0.
The range is preferably from 01 to 100, more preferably from 0.1 to 10. When this ratio is smaller than 0.01, the reaction by water is mainly performed, and the film quality of the obtained ceramic is deteriorated. On the other hand, when it is larger than 100, the hydrolysis rate of the alkoxysilane becomes slow. The reactivity of the mixed solution can be controlled by changing the ratio.

The thickness of the SiO ₂ film obtained by one application is preferably 1 to 5 μm, more preferably 1 to 2 μm.
Range. When the film thickness is thicker than 5 μm, cracking often occurs during heat treatment, and haze increases (hence the haze ratio is preferably 3% or less for a transparent film). On the other hand, if the film thickness is less than 1 μm, the desired effect, for example, desired anti-UV property and hardness cannot be obtained. This film thickness can be controlled by changing the concentration of the coating composition. That is, in order to increase the film thickness, the solid content concentration of the coating composition can be increased (the solvent concentration can be decreased). Further, the film thickness can be further increased by applying the coating composition a plurality of times.

Thus, when the coating composition of the present invention is fired, a high hardness and dense ceramic film having a hardness of 2H or more, further 4H or more (pencil hardness) is obtained, and the visible light transmittance thereof is 80% or more, Furthermore, it can be 95% or more.

Comparative Example 1 A wood protective colorant (Warshin Chemical Co., Ltd., Guardlac G-8 Maple) was applied to a well-prepared oak veneer (100 × 100 × 8), and the mixture was kept at room temperature (22 ° C.) for 3 hours. The sample dried for one day was designated as Comparative Sample-1. Example 1 (A) Low temperature type perhydropolysilazane PHP manufactured by Tonen
S-1 (Mn≈800) 20 wt% xylene solution. (B) Sumitomo Cement ZnO dispersion ZS-303 30
wt% toluene solution. Mix (A) and (B), stir with a stirrer for 3 hours,
The coating solution was uniform. The mixing ratio is 0 wt% and 60% of ZnO in the total solid content (polysilazane + ZnO).
wt% and 80 wt%. The total solid content is 20wt
Adjusted to xylene with xylene.

In order to measure the optical performance and hardness of the obtained coating liquid, a PET film (thickness of 75 μm) was applied by a flow coating method, and ZnO of 0 wt% (1-
1), ZnO 60 wt% (3-1), ZnO
The one having 80 wt% was defined as (4-1). Further, as a durability test for a wood sample, it was applied on Comparative Sample-1 by a brush coating method, and ZnO of 0 wt% was applied to (1-2), Zn.
The one having 60 wt% of O was designated as (3-2) and the one having 80 wt% of ZnO was designated as (4-2). And after coating each room temperature (21
Aged at -25 ° C and humidity of 60-80% for 1 week. The ceramic film thicknesses obtained were all about 2 μm. Table 1 shows the results of the optical performance and hardness, and Table 2 shows the results of the durability test.

Example 2 In the above coating liquid, ZnO of 0 wt% was PET.
Apply it to the film (75 μm) by the flow coating method and apply 1
After drying at 20 ° C for 1 hour, further 3 at 95 ° C / 80% RH
The one subjected to the time humidification treatment was designated as (2). The ceramic film thickness obtained was about 2 μm. The optical performance and hardness are shown in Table-1. Example 3 (D) TiO ₂ powder IT-UD manufactured by Idemitsu Kosan The powder of (D) was added and ultrasonically dispersed for 20 minutes to obtain a uniform coating liquid. The proportion of TiO ₂ in the total solid content was 25%. The concentration of total solids is 20%
It was adjusted with xylene so that The obtained coating liquid was applied to a PET film (75 μm) by a flow coating method, and this was applied at room temperature (21 to 25 ° C., humidity 60 to 80).
%), Which was aged for 1 week as (5). The ceramic film thickness obtained was about 2 μm. The optical performance and hardness are shown in Table-1.

The following equipment was used to measure the optical performance and hardness. UV cut ability measurement: Hitachi Ltd. U-4000 type self-recording spectrophotometer Transparency measurement: Nippon Denshoku Industries Ltd. 300A type haze meter Super UV tester: Dainippon Plastics SUV-W13 type Abrasion test: Taber abrasion tester, AB-101 type abrasion wheel CS-10 manufactured by Tester Sangyo Co., Ltd., load 500
g

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

EFFECTS OF THE INVENTION The ceramic film according to the present invention is substantially transparent, can take advantage of the texture of wood, can be applied at room temperature, and has an excellent UV-cutting ability. It is useful.

Claims (2)

[Claims] 1. Zn having an average particle size of 0.005 to 0.1 μm
O and / or TiO ₂Containing ultrafine particles of nitrogen
SiO containing 0.005 to 5% in percentage₂Membrane on wood surface
UV resistance characterized by having on the surface of painted wood
Wood products. 2. A compound represented by the general formula (I): (However, R ¹ , R ² and R ³ are each independently a hydrogen atom,
An alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a group other than these groups in which the group directly bonded to silicon is carbon, an alkylsilyl group, an alkylamino group, and an alkoxy group. However, at least one of R ¹ , R ² and R ³ is a hydrogen atom) and has a main skeleton composed of a unit represented by a unit represented by the following formula, and the number average molecular weight is 100 to 50,000. A coating composition, to which ZnO and / or TiO ₂ ultrafine particles having a particle size of 0.005 to 0.1 μm is added, is applied to a wood surface or a painted wood surface to convert the composition into a ceramic. Manufacturing method of UV resistant wood products.