JP5457772B2 - Method for imparting antibacterial effect to wooden building materials - Google Patents

Description

  The present invention relates to a method for imparting a good antibacterial effect with excellent safety to a wooden building material such as flooring, furniture, and joinery by a simple method.

  In recent years, there has been a growing trend toward safety and health for various things around us. One example is consumer behavior such as selecting natural products while avoiding synthetic chemical substances.

  The same is true in the living environment, and there is a growing tendency to prefer building materials that use natural materials such as wooden building materials, avoiding building materials that use synthetic resins. On the other hand, consumer cleanliness / safety orientation, which is not always compatible, is also increasing, and products with antibacterial treatment are increasingly preferred.

  The same tendency can be seen in the finish painting of wooden building materials.For example, there is a possibility that a small child may touch or lick on a daily basis on the floor etc. Moreover, the function which suppresses miscellaneous bacteria is also calculated | required.

Conventionally, imparting an antibacterial effect to the painted surface of such wooden building materials has been performed by mixing a chemically synthesized disinfectant into the paint.
For example, as a typical example of such a technique, Patent Document 1 discloses a method in which an antibacterial metal such as silver, cuprous, or zinc is mixed in a synthetic resin paint for wood and applied to a decorative board or the like. Yes.

However, in the method of applying a synthetic resin to a wooden building material, such as the method described in the document, the texture of the wood is impaired because a strong synthetic resin coating film is formed on the surface.
In addition, when the antibacterial effect decreases over time, it is not easy to repaint the synthetic resin coating film again.
Furthermore, in the method described in Patent Document 1, a chemically synthesized disinfectant is used, which is contrary to the trend of consumer preference for emphasizing the recent safety and environmental impact. .

As natural antibacterial active substances, natural fatty acids, fatty acid derivatives and fatty acid esters are known (Non-Patent Document 1).
Non-patent documents 2 to 4 also describe antibacterial activity of long chain fatty acids or long chain fatty acid esters.

Japanese Patent Laid-Open No. 6-198607 JP 2003-290714 A

Kabara J.J., Vrable R., Lie Ken Jie M.S.F., Antimicrobial Lipids: Natural and Synthetic Fatty Acids and Monoglycerides, Lipids, Vol. 12, No. 9, 753-759, 1977 Kabara J.J. et al., Fatty Acids and Derivatives as Antimicrobial Agents, Antimicrobial Agents and Chemotherapy, Vol. 2, No. 1, 23-28, 1972 Conley A.J. et al., Antimicrobial Action of Esters of Polyhydric Alcohols, Antimicrobial Agents and Chemotherapy, Vol. 4, No. 5, 501-506, 1973 Kabara J.J. et al., Antimicrobial Action of Isomeric Fatty Acids on Group A Streptococcus, Journal of Medicinal Chemistry, Vol. 16, No. 9, 1060-1063, 1973

However, in the method of mixing a disinfectant into the synthetic resin paint, the texture specific to wood is lost due to the resin coating film formed on the surface of the wooden building material.
Synthetic disinfectants and synthetic resin coatings are not necessarily accepted by recent consumers who are more natural materials oriented, even if they are relatively safe. Furthermore, the antibacterial activity of the long chain fatty acid or the long chain fatty acid ester is only the activity confirmed by the petri dish test, and the antibacterial activity in the wooden building material is not known.

Accordingly, an object of the present invention is to provide an antibacterial effect by a safer means while maintaining the texture of wood in a wooden building material.
Another object of the present invention is to provide a wooden building material using a natural material to which an antibacterial effect is imparted by safer means.

  The present inventors have intensively studied to solve the above problems, and surprisingly, certain natural fats and oils have an activity of imparting an antibacterial effect to the wooden building materials without interfering with the texture of the wooden building materials. As a result of further finding out, the present invention has been completed.

That is, the present invention relates to a method for imparting an antibacterial effect to a wooden building material, the method including a step of applying a composition containing cocoon oil to the wooden building material.
Furthermore, the present invention relates to the method, wherein the composition further comprises a desiccant.
The present invention also relates to the above method, wherein the cocoon oil is stand oil and / or boiled oil.

The present invention also relates to the above method, wherein the composition consists only of refined camellia oil.
The present invention also relates to the above method, wherein the antibacterial effect is a bactericidal effect against gram positive bacteria and gram negative bacteria.
Furthermore, this invention relates to the wooden building material provided with the antimicrobial effect by the said method.
Furthermore, the present invention relates to a composition for imparting an antibacterial effect to a woody building material containing cocoon oil.
And this invention relates to the said composition which is the shape of a coating material.

According to the method of the present invention, an antibacterial effect can be imparted using natural vegetable oils and fats excellent in safety while maintaining the texture of wood.
Further, even if the antibacterial effect is lost over time, it can be reapplied very easily by such a method, and the antibacterial effect can be imparted again. That is, the method of the present invention is excellent in convenience.

Moreover, according to the method of the present invention, the composition further includes a desiccant, so that the drying property is higher, the permeability of the antibacterial active substance is improved, and the surface of the wooden building material is physically protected. Therefore, an effect that the usability is more excellent is exhibited.
Among the methods of the present invention, according to the method in which the cocoon oil is stand oil and / or boiled oil, the drying property of the cocoon oil is further improved, and thus the effect of further improving the ease of use is exhibited.
Further, among the methods of the present invention, according to a method in which the composition is composed only of refined camellia oil, there is an effect that the composition is more easily prepared.
Among the methods of the present invention, according to the method in which the antibacterial effect is a bactericidal effect against Gram-positive bacteria and Gram-negative bacteria, a bactericidal effect against a wide range of bacteria such as Staphylococcus aureus and Escherichia coli can be imparted.

In the wooden building material of the present invention, the effects of maintaining the texture of wood, excellent safety and antibacterial properties are exhibited.
Furthermore, according to the composition of this invention, the effect that a high antimicrobial effect can be provided to a wooden building material is show | played.
And according to the composition which is the shape of a coating material among the compositions of this invention, the effect that a high antibacterial effect can be provided to a wooden building material is show | played more easily.

  As described above, according to the present invention, it is possible to impart an antibacterial effect to a wooden building material without impairing the texture of wood, particularly wood. Moreover, according to the present invention, the antibacterial effect can be imparted extremely easily and repeatedly.

  In addition, coconut oil is a natural fat and oil classified as vegetable dry oil. As vegetable dry oil or semi-dry oil, flaxseed oil, safflower oil, soybean oil, tung oil, dehydrated castor oil Also known are walnut oil, sunflower oil, sesame oil, rapeseed oil, nutka oil, cottonseed oil and the like. However, no antibacterial activity has been reported for these oils and fats, including camellia oil.

The present invention will be further described based on its embodiments.
In the present specification, “wood texture” refers to, for example, the appearance and feel of wood. The “wood part” means a real wood part excluding a resin part, particularly a real wood part relating to appearance and touch.
In the present specification, the “woody building material” means a building material substantially composed only of natural materials such as wood and wood.
In the present specification, the “antibacterial effect” means an action of suppressing or killing bacterial growth, and the degree thereof is not considered.

The composition used in the present invention is not particularly limited as long as it contains camellia oil. The amount of cocoon oil in the composition is not limited, and for example, it is 10 to 100% by weight, preferably 15 to 90% by weight, more preferably 20% by weight, based on the whole composition. ~ 80% by weight.
Camellia oil is a natural oil that belongs to vegetable dry oil and semi-dry oil. Therefore, the method of the present invention makes it possible to reduce the load and influence on the environment and the human body by using cocoon oil, and further provides a dry property and imparts an antibacterial effect to the wooden building material. As a method that can be easily implemented.

In addition, camellia oil is a vegetable oil rich in sesame, and its main component is _C18 unsaturated fatty acid ester (triglyceride) of oleic acid ester, linoleic acid ester and linolenic acid ester. It is also known that camellia oil contains minerals such as iron, calcium and magnesium, and luteolin. As the cocoon oil used in the present invention, refined cocoon oil is preferable.

  The straw oil used in the present invention is preferably heat-treated with stand oil, boiled oil or the like in order to further improve the drying property. Stand oil is oil that has been superheated and polymerized at a high temperature in a state where air is shut off, and boiled oil is oil that is heated while blowing air or in contact with air. Therefore, the cocoon oil in the present invention includes cocoon oil that has been subjected to a process for making it stand oil or boiled oil.

  In addition, the cocoon oil used in the present invention may be subjected to chemical modification such as epoxidation for the purpose of further increasing the reactivity within a range not impairing the object of the present invention.

In the method of imparting an antibacterial effect to the wood of the present invention, it is preferable to add a desiccant such as a fatty acid metal salt to the camellia oil from the viewpoint of improving the drying property. Examples of such fatty acid metal salts include cobalt naphthenate, cobalt octylate, manganese naphthenate, manganese octylate, lead naphthenate, octyl lead, zinc naphthenate, zinc octylate, calcium naphthenate, calcium octylate. , Zirconium naphthenate, zirconium octylate and the like. These desiccants may be used individually by 1 type, and may be used in combination of 2 or more type.
In the present invention, the amount of the desiccant in the composition is not limited, and examples include 0.05% to 10% by weight, preferably 0.1% to 5% by weight based on the entire composition. More preferably, it is 0.2 wt% to 3 wt%.

  In the present invention, it is needless to say that such a desiccant does not impart an antibacterial effect, but only uses the antibacterial effect of cocoon oil.

  In the method of the present invention, it is preferable to use a diluent in order to improve workability and improve the permeability of the antibacterial active substance to wood. The diluent is preferably an isoparaffin solvent from the viewpoint of safety and convenience.

In the method of the present invention, it is preferable to use wax as a component of the composition for protecting the surface of the wooden building material. There is no particular limitation on the wax used in the method of the present invention, and an example thereof is beeswax.
Among the methods of the present invention, those in which the composition comprises cocoon oil, desiccant, wax and diluent are preferred, and those in which the composition consists of cocoon oil, desiccant, wax and diluent are more preferred.
In the present invention, the amount of the wax in the composition is not limited, and examples include 0.5% to 20% by weight, preferably 1% to 10% by weight, and more. Preferably it is 2 to 5% by weight.
In the present invention, the amount of the diluent in the composition is not limited, and may be appropriately selected in consideration of the type and amount of other components in the composition, the properties of the composition, and the like.

In the method of the present invention, examples of the method for applying the composition to wood include coating treatment, immersion treatment, and forced impregnation treatment.
The application treatment is a treatment for applying the vegetable oil to the surface of the wood to be treated. As the application method, various known methods such as waste cloth, brush, spray, roll coater and the like can be employed without particular limitation.
The dipping treatment is a treatment in which wood to be treated is dipped in the vegetable oil and fat. For example, wood is dipped in a wood protective agent placed in a container.

  The forced impregnation treatment is a treatment for forcibly impregnating (injecting) the vegetable oil into the wood to be treated. As the forced impregnation treatment, various known methods such as a pressure reduction method, a pressure method, a pressure reduction method, a hot bath method, a hot and cold repeated method, a submerged roll press method, and the like can be employed without particular limitation.

  Further, in the various processing methods described above, the same type of processing may be repeated, or two or more different types of processing may be combined and sequentially performed.

In the method of the present invention, the treatment amount of the composition necessary for imparting good antibacterial properties to the wooden building material is the one treatment amount per unit area because the purpose is to ensure the antibacterial properties of the surface. expressed. Such processing amount, preferably a 10 to 50 g / ^{m 2,} more preferably from 20 to 40 g / ^{m 2.} In addition, this processing amount shows the residual amount after wiping off the excess fat on the surface after processing.

In the method of the present invention, it is preferable to dry the treated wooden building material.
As a method for drying the wooden building material after the treatment, various known drying methods can be used without particular limitation in the painting of wood and the like, and natural drying, hot air drying and the like can be mentioned. Further, as disclosed in Patent Document 2, it is also possible to use a method in which the temperature of the resin is increased by rotating the heating roll while pressing it after coating.

  It is also known that fats and oils become aldehydes such as formaldehyde when dried (oxidized). Therefore, in the method of the present invention, after the above-described coating treatment, immersion treatment, forced impregnation treatment, etc., the excess resin is wiped off with a waste cloth or the like for the purpose of suppressing the generation of formaldehyde or the like and further improving the drying property. Is preferred.

  Bacteria that are targets of the method of the present invention are not particularly limited, and both gram positive bacteria and gram negative bacteria are suitable targets. The method of the present invention in which the antibacterial effect is a bactericidal effect against Gram-positive bacteria and Gram-negative bacteria is preferable since antibacterial activity by fatty acids and fatty acid esters has been recognized only against Gram-positive bacteria (Non-patented) Literature 2-4).

  In the present invention, the wood (treated wood) to which the antibacterial effect is imparted may be a solid wood obtained by sawing softwood or hardwood, a laminated wood, or various woody materials. Examples of the wood material include plywood, veneer laminate (LVL), particle board, MDF, and the like.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

[Evaluation of antibacterial properties]
Antibacterial evaluation was performed according to the JIS Z 2801 film adhesion method.
Sample preparation The sample solution was uniformly applied to copy paper (plain paper) so as to be about 0.2 ml per 5 cm ² and then dried at room temperature for 24 hours.

Preparation of Test Bacteria Solution The test bacteria that had been pre-cultured in NA medium at 30 ° C. for 18 hours were diluted with sterilized purified water so that the number of bacteria became 2.5 to 10 × 10 ⁵ / ml. What added the NB culture medium so that it might become a density | concentration 1/500 was made into the fungus | bacteria liquid for inoculation.
The test operation test piece was put in a petri dish, 0.4 ml of the test bacterial solution was inoculated, covered with a polyethylene film cut to 40 mm × 40 mm, and left for 24 hours in an environment of 30 ° C. and 95% relative humidity.

  After 24 hours, 10 ml of SCDLP medium was added to each dish, and the bacteria adhering to the film and the test piece were thoroughly washed out in the dish, and the number of viable bacteria in 1 ml of this solution was measured using SA medium. An empty petri dish inoculated with only the test bacterial solution was used as a control.

Medium composition
1) Normal bouillon medium (NB medium)
Meat extract 3.0g
Peptone 10.0g
Sodium chloride 5.0g
Purified water 1000 ml
pH 7.1

2) Ordinary agar medium (NA medium)
Meat extract 5.0g
Peptone 10.0g
Sodium chloride 5.0g
Agar 15.0g
Purified water 1000 ml
pH 7.1

3) Standard agar medium (SA medium)
Yeast extract 2.5g
Tryptone 5.0g
Glucose 1.0g
Agar 15.0g
Purified water 1000 ml
pH 7.1

4) SCDLP medium casein pept 17.0g
Soybean peptone 3.0g
Sodium chloride 5.0g
Dipotassium hydrogen phosphate 2.5g
Glucose 2.5g
Lecithin 1.0g
Polysorbate 80 7.0g
Purified water 1000 ml
pH 7.0

The following two types of bacteria were used for the test bacteria test solution. Escherichia coli IFO 3972 was used as a gram-negative bacterium, and Staphylococcus aureus subsp . Aureus IFO 12732 was used as a gram-positive bacterium.

Example 1
The composition of Example 1 was obtained using refined cocoon oil as cocoon oil.

(Example 2)
A composition prepared by adding a desiccant, a wax, and a diluent from a boiled refined camellia oil as a raw material was designated as Example 2. The composition of the paint (composition) was as follows, and the entire paint was 100 parts by weight.
Boiled refined camellia oil: 20 parts by weight Beeswax: 2 parts by weight Metal soap desiccant: 0.2 parts by weight Isoparaffin solvent: remainder

(Comparative Example 1)
A sample obtained by inoculating an empty petri dish with only the test bacterial solution was used as Comparative Example 1 (control).

[Results and discussion]
The results are shown in Tables 1 and 2 below.
(Result: E. coli)

(Result: Staphylococcus aureus)

However,
Antibacterial activity value = (number of viable bacteria of blank (or control) after 24 hours)-(number of viable bacteria of antibacterial agent-added product after 24 hours).

As shown in Tables 1 and 2, from the test piece coated with Example 1 or 2, almost no viable cell count was detected after 24 hours for any of the test bacteria.
When the antibacterial activity value, which is a criterion for antibacterial performance, was determined according to JIS standards using the control bacterial solution (Comparative Example 1) as a reference, it showed a good antibacterial efficacy of 5.0 or more, 5.0.
Therefore, it is judged that both the compositions of Examples 1 and 2 have sufficient antibacterial performance.

  Moreover, when the composition of Example 1 or 2 was applied to oak and dried, a good wood texture was maintained.

  In Example 1, since the antimicrobial activity was shown by the test composition, it was clarified that the antibacterial effect exists in the cocoon oil itself. In Example 2, a good antibacterial effect was also confirmed in the test composition. Accordingly, it has been clarified that a composition (paint) containing cocoon oil suitable for imparting an antibacterial effect to a wooden building material without impairing the original antibacterial effect of cocoon oil is provided.

  As described above, according to the present invention, excellent safety and a good antibacterial effect can be imparted by a simple method without impairing the texture of wooden building materials such as flooring, furniture, and joinery. In particular, the present invention imparts antibacterial activity to both gram-positive bacteria (such as Staphylococcus aureus) and gram-negative bacteria (E. coli), which is a very special effect from the viewpoint of the antibacterial spectrum.

  The fatty acid composition of coconut oil is 20 parts by weight of oleic acid, 13 parts by weight of linoleic acid, 60 parts by weight of linolenic acid, and the rest. On the other hand, the fatty acid composition of linseed oil often used for paints and the like is 22 parts by weight of oleic acid, 16 parts by weight of linoleic acid, 52 parts by weight of linolenic acid, and the rest. However, it was confirmed that linseed oil has no antibacterial activity.

  According to the present invention, in a wooden building material, a method for imparting an antibacterial effect while maintaining the texture of wood, a composition for such a method, and a wooden building material having an antibacterial effect and maintaining the texture of wood Is provided. Therefore, the present invention greatly contributes to the development of the wooden building material manufacturing industry and related industries.

Claims (6)

  A method for imparting an antibacterial effect to a wooden building material, the method comprising a step of applying to the wooden building material a composition containing straw oil and not containing water.   The method of claim 1, wherein the composition further comprises a desiccant.   The method according to claim 1 or 2, wherein the cocoon oil is stand oil and / or boiled oil.   The method of claim 1, wherein the composition consists only of refined camellia oil.   The method according to any one of claims 1 to 4, wherein the antibacterial effect is a bactericidal effect against gram positive bacteria and gram negative bacteria.   A wooden building material provided with an antibacterial effect by the method according to claim 1.