KR20230102401A - Coating material for wood - Google Patents

Abstract

The present invention relates to a coating agent for wood, and includes a crosslinking agent selected from the group consisting of water-based acrylic resin emulsion, rosin and oxazoline-based compounds, carbodiimide-based compounds, aziridine-based compounds and hydrazine-based compounds and having reactivity with a carboxyl group. It is about.
According to the present invention, since rosin is contained in the wood coating composition, adhesion, mold resistance, and gloss are improved, and even when rosin is contained, resin components are crosslinked by a crosslinking agent, so that degradation of properties over time is suppressed and durability is improved. improve

Description

Coating material for wood}

The present invention relates to a coating agent for wood, and more particularly, to a coating agent composition for wood with improved durability of the coating agent.

Wood is used as a material for houses or furniture in the form of raw wood or processed plywood.

Wood coating agents are generally applied to the surface of wood and penetrate into the wood to prevent decay, deformation, and cracking of wood and to express natural pattern texture.

Paints used as wood coatings are generally classified into oil-based paints and water-based paints.

Since oil-based paints use organic solvents such as hydrocarbons and ketones as solvents, the risk of fire is high and harmful to the human body and the atmospheric environment.

Water-based paints use water instead of organic solvents and are safe. There are emulsion paints and water-soluble baking resin paints, but they have disadvantages such as inferior outdoor exposure, water resistance, and mold resistance compared to oil-based paints.

An example of a water-based paint is shown in Korean Patent Registration No. 1289641 filed by the present inventor.

It is described that when the water-based paint according to the above patent is applied to wood, the effect of preventing cracking of wood appears.

However, improvement of various characteristics is still required.

An object of the present invention is to improve the properties by using specific components in a coating composition for wood in order to solve the above-mentioned disadvantages and meet the needs.

In order to achieve the above object, the present invention, in terms of solid content of the aqueous acrylic resin emulsion, 20 to 30% by weight, 5 to 10% by weight of rosin, 3 to 7% by weight of a crosslinking agent reactive to a carboxyl group, dipropylene glycol monomethyl ether 1 to 5% by weight of a surfactant containing at least one component selected from the group consisting of sodium dodecylbenzenesulfonate, sodium lauryl sulfate and octylphenol ethoxylate, and 1 to 5% by weight of a water-soluble containing water An eco-friendly water-based wood coating agent based on the present invention is provided.

In addition, the present invention is a water-based acrylic resin emulsion, a group consisting of rosin, a crosslinking agent reactive with a carboxyl group, dipropylene glycol monomethyl ether, sodium dodecylbenzenesulfonate, sodium lauryl sulfate and octylphenol ethoxylate It provides a method for preparing by mixing a surfactant and water containing at least one component selected from among.

In addition, the present invention is a surfactant containing at least one component selected from the group consisting of rosin, dipropylene glycol monomethyl ether, and sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and octylphenol ethoxylate in water. rosin emulsion mixed and emulsified; water-based acrylic resin emulsion; And a crosslinking agent having reactivity to the carboxyl group; it provides a method for preparing by mixing.

According to the present invention, since rosin is contained in the wood coating composition, adhesion, mold resistance, and gloss are improved, and even when rosin is contained, resin components are crosslinked by a crosslinking agent, so that degradation of properties over time is suppressed and durability is improved. improve

The present invention is a wood coating agent comprising a water-based acrylic resin emulsion, rosin, and a crosslinking agent selected from the group consisting of oxazoline, carbodiimide, aziridine, and hydrazine compounds and having reactivity with a carboxyl group.

The present invention improves adhesion, flexibility and antibacterial properties by adding rosin to a water-based acrylic resin from the viewpoint of environmental protection and hygiene.

At this time, by adding a crosslinking agent having reactivity with the carboxyl group, the preservation stability of the coating agent is improved, and the durability of the coating film is improved so that the properties are maintained even after the lapse of time.

The water-based acrylic resin emulsion of the present invention may be prepared by various known methods.

For example, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, normal butyl (meth) acrylate, isobutyl (meth) acrylate, lauryl (meth) acrylate, ester 30 to 70 parts by weight of an acrylic acid ester monomer selected from the group consisting of aryl (meth) acrylate, butyl acrylate, beta-hydroxybutyl (meth) acrylate, di (ethylene glycol) mono (meth) acrylate, styrene , 10 to 50 parts by weight of an aromatic vinyl monomer selected from the group consisting of α-methylstyrene, trans-β-methylstyrene, β-methylstyrene, 4-methylstyrene, etc., fumaric acid ester or modified methacrylamide to promote adhesion 10 to 60 parts by weight of a monomer mixture containing 1 to 10 parts by weight of an acrylic monomer and 0.5 to 4 parts by weight of an organic acid monomer selected from acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, etc., and ammonium persulfate and sodium persulfate An acrylic resin emulsion can be prepared by preparing an addition polymerization mixture by mixing 0.1 to 1 part by weight of a radical polymerization initiation catalyst selected from potassium persulfate and the like, and adjusting the pH of the mixture to 8 to 10.

The obtained acrylic emulsion resin preferably has a glass transition temperature of 40 to 90 °C. If the glass transition temperature is less than 40 ° C, the tack free property is lowered, and if it exceeds 90 ° C, the coating film is hard and the flexibility is poor. In addition, when a coating film aid is used to produce a uniform coating film, the amount used increases, resulting in poor workability.

The water-based acrylic resin emulsion of the present invention, in the form of an emulsion, has compatibility with other resin components, can increase the solid content, and has excellent transparency. On the other hand, it has poor water resistance and a discontinuous film is formed, so it is easy to deteriorate the adhesive strength with wood.

The water-based acrylic resin emulsion of the present invention preferably contains 20 to 30% by weight in the coating agent in terms of solid content. If it is less than 20% by weight, the wood protection function is not expressed and it is difficult to form a coating film, and if it is more than 30% by weight Doing so may reduce adhesion.

In the present invention, rosin is further added to compensate for this and improve physical properties and adhesiveness.

Pine Resin refers to the balsam secreted when trees in the pine family are damaged. Resin can be obtained, for example, by wounding a tree of the Pinaceae family. Resin is a colorless and transparent liquid when it is secreted from trees, but has a high viscosity that becomes cloudy and sticky over time. Such rosin is known to contain 70 to 75% by weight of rosin made of resin acids such as abietic acid, 18 to 22% by weight of turpentine, and 5 to 7% by weight of water or other impurities. .

Since rosin is composed of the above components, it is possible to provide a waterproofing agent composition having excellent adhesiveness, waterproofness and moisture resistance. In addition, it exhibits gloss, and the essential oil component constituting rosin exhibits antibacterial and bactericidal properties, thereby providing an antiseptic effect.

As the rosin used in the present invention, for example, rosin distributed in the art may be purchased and used, or obtained by scratching a tree of the Pinaceae family, and may be used after removing suspended matter and the like through filtration.

The rosin of the present invention is preferably contained in an amount of 5 to 10% by weight in the coating agent. If it is less than 5% by weight, the properties due to rosin do not appear and the coating film does not become hard, and if it exceeds 10% by weight, the water-based acrylic resin and rosin Phase separation from each other may reduce mechanical strength and durability.

In the present invention, since a crosslinking agent is added and used together, the resin acid, the acrylic resin, and the crosslinking agent constituting the rosin are integrated by crosslinking, so that the coating composition does not phase separate, so the storage stability is improved and the formed coating film is hardened to improve durability.

The crosslinking agent of the present invention is a crosslinking agent having reactivity to the carboxyl group of rosin, and is at least one selected from the group consisting of oxazoline-based compounds, carbodiimide-based compounds, aziridine-based compounds and hydrazine-based compounds. From this point of view, oxazoline-based compounds and carbodiimide-based compounds are more preferred.

The oxazoline compound, for example, 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-isopropyl-2-oxazoline, 2-n-propyl-2-oxazoline, 2 -vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, etc. Commercially available products include EPOCROS (Nippon Catalyst Co., Ltd.) and the like.

Examples of the carbodiimide-based compound include Carbodilite (Nisshinbo Chemical Inc.) as a commercial product.

Examples of the aziridine-based compound include 1-(methylene di-p-phenylene) bis-3,3-aziridinyl urea, 1,1'-(hexamethylene) bis-3,3-aziridinyl urea, and ethylene bis. -(2-aziridinylpropionate), 2,4,6-triaziridinyl 1,3,5-triazine, etc., and Chemitite (Nippon Catalyst Co., Ltd.) are commercially available.

Examples of the hydrazine-based compound include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, and fumaric acid dihydrazide. Hydrazide, itaconic acid dihydrazide, etc. are mentioned.

The crosslinking agent can improve the preservation (storage) stability of the water-based coating agent and the adhesiveness and durability of the coating film.

The crosslinking agent of the present invention is preferably contained in an amount of 3 to 7% by weight in the coating agent. If it is less than 3% by weight, the crosslinking reaction is insufficient and it is difficult to form a high molecular weight, so the durability of the coating film is reduced, and if it exceeds 7% by weight, it is cured. The excessive amount of adhesiveness deteriorates and the coating film becomes hard, which is economically undesirable.

By using dipropylene glycol monomethyl ether as a component of the coating composition of the present invention, waterproofness is improved and lubricity is provided, thereby facilitating the coating operation and improving adhesion to wood.

Dipropylene glycol monomethyl ether of the present invention is preferably contained in an amount of 1 to 5% by weight in the coating agent. If the content is less than 1% by weight, the adhesion to wood is reduced, and if it exceeds 5% by weight, the hydrophobic property is strongly expressed. and the solubility deteriorates.

A surfactant containing at least one component selected from the group consisting of sodium dodecylbenzenesulfonate, sodium lauryl sulfate and octylphenol ethoxylate may be used as a component of the coating composition of the present invention.

As a result, aggregation of components constituting the coating agent is suppressed, storage stability is improved, and a uniform coating film can be formed.

The surfactant of the present invention is preferably contained in an amount of 1 to 5% by weight in the coating agent. If it is less than 1% by weight, storage stability may decrease, and if it exceeds 5% by weight, the water resistance of the coating film may decrease.

The wood coating agent of the present invention comprises the steps of preparing a water-based acrylic resin emulsion; and at least one selected from the group consisting of water, rosin, a crosslinking agent reactive with a carboxyl group, dipropylene glycol monomethyl ether, and sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and octylphenol ethoxylate in the aqueous acrylic resin emulsion. Adding and mixing a surfactant containing one or more components, 20 to 30% by weight in terms of solid content of the aqueous acrylic resin emulsion, 5 to 10% by weight of rosin, 3 to 7% by weight of a crosslinking agent reactive to carboxyl groups, dipropylene It can be prepared by including the step of preparing a composition consisting of 1 to 5% by weight of glycol monomethyl ether, 1 to 5% by weight of a surfactant, and the balance of water.

In addition, preparing a water-based acrylic resin emulsion; A rosin emulsion obtained by mixing and emulsifying a surfactant containing rosin, dipropylene glycol monomethyl ether, and at least one component selected from the group consisting of sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and octylphenol ethoxylate in water. preparing; And mixing the water-based acrylic resin emulsion, rosin emulsion, and a crosslinking agent having reactivity to carboxyl groups, in terms of solid content of the water-based acrylic resin emulsion, 20 to 30% by weight, 5 to 10% by weight of rosin, reactive to carboxyl groups 3 to 7% by weight of a crosslinking agent, 1 to 5% by weight of dipropylene glycol monomethyl ether, 1 to 5% by weight of a surfactant, and the remaining amount of water.

However, in any case, it may not be easy to disperse, mix, and sufficiently emulsify the acrylic resin and rosin in an aqueous system.

Conventionally, a rosin emulsion can be made using an anionic or nonionic emulsifier, but this may cause a lot of aggregates and insufficient emulsification. In addition, the emulsifier (surfactant) combines with moisture to reduce the adhesive strength and physical properties of the coating film, which makes it difficult to use for a long time.

In order to provide an aqueous wood coating agent with improved emulsification and storage stability, the present invention uses polyoxyethylene tridecyl ether sodium phosphate (for example, trade name "Rhodafac RS-610", etc. ), sodium dodecyl diphenyl ether sulfonate (for example, trade name "DowFax8390", etc., manufactured by Dow Chemical) and sodium dilauroylglutamic acid lysine (for example, trade name "Pellicer", etc., Asahi Kasei Fine-Chem) An emulsifier selected from (a)) may be used.

The emulsifier is a multi-chain polyhydrophilic compound, which contains at least two hydrophobic chains and hydrophilic groups in a molecule, thereby improving emulsification, dispersibility, and mixing with the acrylic resin emulsion in the coating agent, and the characteristics of the coating agent of the present invention Deterioration, in particular, deterioration of durability can be suppressed.

The emulsifier is preferably added at a ratio of 1 to 2 parts by weight relative to 100 parts by weight of rosin. If it is less than 1 part by weight, it is difficult to express emulsification, and if it exceeds 2 parts by weight, water resistance is reduced.

Due to the use of the emulsifier, a sufficient emulsifying effect can be expressed with a smaller amount than conventional anionic or nonionic emulsifiers.

The wood coating agent prepared by mixing the rosin emulsion of the present invention with the acrylic resin emulsion has good water whitening resistance and maintains adhesiveness and transparency even over time in a moisture or humid environment, so it has good design and durability. this can be improved.

The rosin emulsion can be prepared by a conventional high-pressure emulsification method.

The high-pressure emulsification method is a method formed by making rosin into a liquid phase using an organic solvent, mixing an emulsifier and water, performing fine emulsification using a high-pressure emulsifier, and removing the organic solvent.

Hereinafter, the present invention will be described in more detail through the following Examples and Comparative Examples.

These Examples and Comparative Examples are only for explaining the present invention in more detail, and it is to those skilled in the art that the subject matter of the present invention is not limited by these Examples according to the subject matter of the present invention. It will be self-explanatory.

[Production Example]

A thermometer, condenser, stirrer, and temperature increasing device were attached to a 2-liter four-necked glass flask.

620 g of deionized water, 30 g of sodium lauryl sulfate, and 28 g of octylphenol ethoxylate were added thereto, and the temperature was raised to 80°C.

In a separate container, 251 g of deionized water, 30 g of sodium lauryl sulfate, 28 g of octylphenol ethoxylate, 492 g of methyl methacrylate, 102 g of ethyl acrylate, 61 g of methacrylic acid, 2 g of azobisisobutylnitrile was added and stirred to emulsify to obtain an emulsion.

After putting 20 g of the emulsion into a flask and synthesizing a seed, emulsion polymerization was performed while uniformly dropping 987 g of the remaining emulsion into the flask for 3 hours. The non-volatile content (solid content) of the acrylic resin emulsion thus synthesized was 45% by weight, viscosity 200 cps, glass transition temperature 82°C, and pH 9.

[Example 1]

150 g of rosin was dissolved in 150 g of toluene, and 45 g of dipropylene glycol monomethyl ether, 45 g of sodium dodecylbenzenesulfonate, and 240 g of hot water at 60 ° C were added and mixed, emulsified in a high-pressure emulsifier, and reduced to obtain toluene. It was removed to prepare a rosin emulsion with a solid content of 50%.

A wood coating agent was prepared by mixing 1,000 g of the acrylic resin emulsion of Preparation Example, 480 g of the rosin emulsion, and 225 g of an oxazoline-based crosslinking agent (Epocross K-2010 E (solid content: 40% by weight), Japanese catalyst).

[Example 2]

The same method as in Example 1 was used except for using 225 g of a carbodiimide-based crosslinking agent (Carbodilite E-02 (solid content: 40% by weight), Nisshinbo Chemical Inc.) instead of the oxazoline-based crosslinking agent in Example 1. Thus, a wood coating agent was prepared.

[Example 3]

A wood coating agent was prepared in the same manner as in Example 1, except that 90 g of an aziridine-based crosslinking agent (Chemitite PZ-33 (99% by weight solids), Japanese catalyst) was used instead of the oxazoline-based crosslinking agent in Example 1. manufactured.

[Example 4]

In Example 1, 150 g of rosin was dissolved in 150 g of toluene, 45 g of dipropylene glycol monomethyl ether, 45 g of sodium dodecylbenzenesulfonate, sodium polyoxyethylene tridecyl ether phosphate (trade name “Rhodafac RS-610 ", Solvaylation (formula) 2 g and 242 g of hot water at 60 ° C were added and mixed, emulsified in a high-pressure emulsifier, and reduced pressure to remove toluene to prepare a rosin emulsion with a solid content of 50%. Except for using, A wood coating agent was prepared using the same method as in Example 1.

[Example 5]

In Example 1, 150 g of rosin was dissolved in 150 g of toluene, 45 g of dipropylene glycol monomethyl ether, 45 g of sodium dodecylbenzenesulfonate, sodium dilauroylglutamic acid lysine (trade name “Pericea (registered trademark) ) 2 g of "L-30" manufactured by Asahi Kasei Finechem Co., Ltd.) and 242 g of hot water at 60 ° C. were added and mixed, emulsified in a high-pressure emulsifier, and reduced pressure to remove toluene to prepare a rosin emulsion with a solid content of 50%. A wood coating agent was prepared using the same method as in Example 1, except that it was used.

[Example 6]

In Example 1, 150 g of rosin was dissolved in 150 g of toluene, 45 g of dipropylene glycol monomethyl ether, 45 g of sodium dodecylbenzenesulfonate, sodium dodecyl diphenyl ether sulfonate (trade name "DowFax8390" Dow Chemical The same method as in Example 1, except that 2 g and 242 g of hot water at 60 ° C. were added and mixed, emulsified in a high-pressure emulsifier, and reduced to remove toluene to prepare a rosin emulsion with a solid content of 50%. A wood coating was prepared using

[Comparative Example 1]

A wood coating agent was prepared in the same manner as in Example 1, except that the crosslinking agent was not used in Example 1.

Various evaluations were performed on the wood coating agents of the Examples and Comparative Examples as follows, and the results are shown in Table 1.

(Assessment Methods)

1. Mold resistance

In accordance with the test method of KS J 3201, it is evaluated according to the rating table below.

At this time, the most common mold (Aspergillus niger) on wood is used.

<Rating table>

Grade 0: The strain does not grow.

Grade 1: less than 10% growth on the specimen,

Grade 2: 10 to 30% growth on the specimen.

Grade 3: 30 to 60% growth on the specimen.

Grade 4: Growth greater than 60% on the specimen.

2. Accelerated weathering

Evaluate the state of the coating according to the test method of KS M 5000.

3. Immersion releasability

Evaluate the state of the coating film according to the test method of KS F 2160.

4. Water resistance adhesion

The coated wood is immersed in room temperature water for 24 hours and completely dried.

The adhesiveness of the tape and the coating was measured by alternating 10 sheaths at 1 mm intervals horizontally and vertically on the coating of the dried coated wood.

5. Transparency

After the coating agent is applied on the wood once, the transparency is evaluated by observing whether the wood grain is clearly visible.

<Transparency Evaluation Criteria>

○: Wood grain is visible, ×: Wood grain is not visible

6. Storage stability

After putting the coating agent in a glass container, sealing it, and leaving it in a constant temperature room at 23° C. for 3 months, the occurrence of precipitate is visually evaluated.

<Evaluation Criteria>

○: Good storage stability (no precipitate)

△: Slightly inferior to storage stability (a small amount of sediment can be confirmed)

×: poor storage stability (a large amount of sediment can be confirmed)

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 comparative example mold
resistance 0 rating 0 rating 0 rating 0 rating 0 rating 0 rating 0 rating Promotion
weather resistance No whitening, cracks or peeling after 4,000 hours No whitening, cracks or peeling after 4,000 hours No whitening, cracking, or peeling after 4,000 hours No whitening, cracking, or peeling after 4,000 hours No whitening, cracks or peeling after 4,000 hours No whitening, cracks or peeling after 4,000 hours White nights and cracks after 1,000 hours immersion
exfoliation clear clear clear clear clear clear 0.5 mm
crack occurrence Domestic consumption
adhesiveness 0/100 0/100 0/100 0/100 0/100 0/100 10/100 transparency ○ ○ ○ ○ ○ ○ ○ save
stability △ △ △ ○ ○ ○ ×

From Table 1, it is confirmed that the examples are superior in accelerated weather resistance, immersion peelability, and water-resistant adhesiveness compared to those of the comparative examples. that is confirmed

On the other hand, the rosin emulsions of Examples 4 to 6 were visually observed to have a good emulsified state. In addition, the residue obtained by filtering the rosin emulsion with a 150 mesh wire mesh was less than 0.1% by weight, indicating that the formation of aggregates in the rosin emulsion was suppressed and the emulsion stability was good.

Accordingly, it is confirmed that the wood coating agent of the present invention in which the rosin emulsion is added and mixed has excellent emulsification and miscibility, thereby improving storage stability.

Claims (6)

20 to 30% by weight in terms of solid content of the aqueous acrylic resin emulsion, 5 to 10% by weight of rosin, 3 to 7% by weight of a crosslinking agent reactive to carboxyl groups, 1 to 5% by weight of dipropylene glycol monomethyl ether, sodium dodecylbenzene A water-soluble, water-soluble, eco-friendly water-based wood coating agent containing 1 to 5% by weight of a surfactant containing at least one component selected from the group consisting of sulfonate, sodium lauryl sulfate, and octylphenol ethoxylate, and the remaining amount of water. According to claim 1,
The crosslinking agent is an aqueous wood coating agent, characterized in that selected from the group consisting of oxazoline-based compounds, carbodiimide-based compounds, aziridine-based compounds and hydrazine-based compounds. According to claim 2,
The oxazoline-based compound is 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-isopropyl-2-oxazoline, 2-n-propyl-2-oxazoline, 2-vinyl- Characterized in that it is selected from 2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline and 2-isopropenyl-4-methyl-2-oxazoline Water-based wood coatings. Preparing a water-based acrylic resin emulsion; and
At least one selected from the group consisting of water, rosin, a crosslinking agent reactive to a carboxyl group, dipropylene glycol monomethyl ether, and sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and octylphenol ethoxylate in the aqueous acrylic resin emulsion By adding and mixing the surfactant containing the above components,
20 to 30% by weight in terms of solid content of the aqueous acrylic resin emulsion, 5 to 10% by weight of rosin, 3 to 7% by weight of a crosslinking agent reactive to carboxyl groups, 1 to 5% by weight of dipropylene glycol monomethyl ether, the above surfactant 1 A method for producing a water-based wood coating comprising the step of preparing a composition consisting of ~5% by weight and the balance of water. Preparing a water-based acrylic resin emulsion;
A rosin emulsion obtained by mixing and emulsifying a surfactant containing rosin, dipropylene glycol monomethyl ether, and at least one component selected from the group consisting of sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and octylphenol ethoxylate in water. preparing; and
The water-based acrylic resin emulsion, rosin emulsion, and a crosslinking agent reactive to the carboxyl group are included and mixed,
20 to 30% by weight in terms of solid content of the aqueous acrylic resin emulsion, 5 to 10% by weight of rosin, 3 to 7% by weight of a crosslinking agent reactive to carboxyl groups, 1 to 5% by weight of dipropylene glycol monomethyl ether, 1 to 10% surfactant A method for producing a water-based wood coating agent comprising the step of preparing a composition consisting of 5% by weight and the balance of water. According to claim 5,
In the step of preparing the rosin emulsion, an emulsifier selected from sodium polyoxyethylene tridecyl ether phosphate, sodium dodecyl diphenyl ether sulfonate and sodium dilauroylglutamic acid lysine is further added to the water-based wood coating agent manufacturing method .