JP2009209237A - Coating material for woodwork - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating material for woodwork, providing coated film properties capable of compensating for the surface hardness of a wood even if the wood is a soft wood such as cedar wood. <P>SOLUTION: The coating material for the woodwork is suitably used for the soft wood such as the cedar wood, and contains a synthetic resin as a main component and 0.5-25 pts.wt. wood powder having wood fiber with a cellulose structure based on the whole amount of the coating material for the woodwork. For example, the coating material for the woodwork is suitably used for undercoat of the soft wood, and is constituted as a two-pack type coating material for the woodwork, used by mixing a coating main agent containing a polyol resin as a main component, with a curing agent containing a polyisocyanate resin as a main component. In the case, the wood powder having the wood fiber with the cellulose structure is added to the coating main agent, and 0.5-25 pts.wt. of the wood powder is contained based on the whole amount of the coating material for the woodwork. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a paint for woodwork, and more particularly to a paint for woodwork that is suitably used for soft wood such as cedar.

A variety of synthetic resin paints mainly composed of synthetic resins are used as woodwork paints.
For example, in a two-component polyurethane resin paint, a curing agent mainly composed of a polyisocyanate resin having NCO groups is mixed with a paint principal component mainly composed of a polyol resin such as polyester, alkyd or acrylic having OH groups. This is a paint that forms a urethane bond and is cured and dried. This two-pack type polyurethane resin coating cures at room temperature and can form a very strong and tough coating film at low cost. Therefore, at present, this two-pack type polyurethane resin paint is widely used as a wood paint.
Japanese Patent Application Laid-Open No. 10-101993 JP-A-2-55464

  By the way, hard wood such as oak and zelkova is generally used for furniture. Soft soft wood such as cedar can not compensate for the strength, especially the physical properties against dents, even if the same paint and painting process as hard wood are applied. Specifically, when cedar is used for the table top plate, it is easy to dent, for example, easily dents with normal writing pressure. Therefore, soft soft wood such as cedar is used less frequently for furniture even when used for building materials.

  On the other hand, cedar wood is abundant as a domestic resource, and is a timber that can be stably supplied by afforestation. In recent cases, the impact on cedar pollinosis has also been sought because of the lack of deforestation and management. Therefore, it is desired that cedar is effectively used not only for building materials but also for general furniture such as tables.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the coating material for woodwork which has the coating-film performance which can supplement the surface hardness even if it is soft wood like cedar. .

  As a result of earnest research focusing on substances added to wood coating materials in order to broaden the range of use of soft wood such as cedar wood, the present inventor has achieved excellent hardness by adding wood flour. It discovered that a coating film was obtained and came to complete this invention.

That is, the woodworking paint according to the present invention is a woodworking paint which is preferably used for soft wood and has a synthetic resin as a main component, and wood powder having wood fibers having a cellulose structure with respect to the whole amount of the woodworking paint. It is contained in an amount of 0.5 to 25 parts by weight.
According to this, a hard coating film that supplements the surface hardness of soft wood such as cedar is formed by the same painting process as before without special equipment.

The woodworking paint according to the present invention is suitably used for undercoating soft wood, and is a two-part woodworking in which a curing agent mainly comprising a polyisocyanate resin is mixed with a coating material mainly comprising a polyol resin. A wood powder having a cellulose fiber of cellulose structure is added to the main paint, and the wood powder is contained in an amount of 0.5 to 25 parts by weight based on the total amount of the wood paint. .
According to this, a hard coating film that supplements the surface hardness of soft wood such as cedar is formed by the same painting process as before without special equipment.

  As described above, according to the present invention, when coated on wood by the same painting process as before, excellent coating performance of a hard material that can supplement the surface hardness of soft wood such as cedar is demonstrated. can do. Therefore, soft wood such as cedar can be effectively used not only for building materials but also for general furniture such as tables, and the range of use of soft wood can be widened.

Hereinafter, embodiments of the present invention will be described.
The woodworking paint according to the present embodiment is suitably used for soft wood and is a woodworking paint mainly composed of a synthetic resin, and the wood powder having wood fibers having a cellulose structure with respect to the total amount of the woodworking paint is 0. 5 to 25 parts by weight is contained. In addition, cedar is mentioned as a soft wood in which this woodworking paint is preferably used, but it is also preferably used in conifers such as pine and cypress.

  As the main component synthetic resin, for example, urethane resin, acrylic resin, epoxy resin, polyester resin, alkyd resin, amino resin, silicon resin, polybutadiene resin, phenol resin, fluorine resin, etc. are used alone or in combination of two or more thereof A combined resin system can be used. Further, any of a normal temperature type, a thermosetting type, and a UV curable type can be used as the resin curing mechanism.

  Any wood flour may be used as long as it has cellulosic wood fibers. For example, wood flour directly carved from wood, white wood fibers bleached, and the like can be used. Note that the purification of wood fibers is not particularly necessary.

  The magnitude | size of a wood fiber will not be specifically limited if the target coating-film hardness is obtained in a coated material. However, it is desirable that the wood fiber has an average fiber length of 100 to 300 μm. That is, when the average fiber length of the wood fibers is less than 100 μm, it may be difficult to secure a surface hardness that allows soft wood such as cedar to be used as furniture such as table tops. On the other hand, if the average fiber length of the wood fibers exceeds 300 μm, the surface of the painted eyebrows may be uneven, resulting in poor smoothness. Therefore, when the average fiber length of the wood fibers is 100 to 300 μm, the coating performance for forming a hard coating film with a smooth coated surface can be easily obtained. Furthermore, it is desirable that the average fiber thickness (diameter) of the wood fiber is 15 to 40 μm, and in that case, it is possible to easily obtain the coating performance that forms a hard coating film with a smooth coated surface.

  And the said wood powder contains 0.5-25 weight part with respect to the woodwork coating material whole quantity. That is, when the content of wood powder is less than 0.5 parts by weight with respect to the total amount of paint for woodwork, it may be difficult to secure a surface hardness that allows soft wood such as cedar to be used as furniture such as table tops. There is. On the other hand, when the content of the wood powder exceeds 25 parts by weight with respect to the total amount of the paint for woodwork, the surface of the coating layer may be uneven and it may be difficult to obtain a smooth coating film.

  Moreover, the paint form of this woodwork paint may be either a one-component type or a multi-component type. As the paint properties, any of an organic solvent type, a water-soluble type, a water dispersion type, and a combination type thereof can be applied. Furthermore, additives such as a dispersant, a pigment, an extender, a colorant, etc. that uniformly disperse the wood powder may be appropriately added to the paint depending on the target performance.

  Examples of the coating method include a spray coating method, a roller coating method, a flow coating method, a brush coating method, a dipping method, and the like. Although not particularly limited, the spray coating method is preferable from the viewpoint of workability. In addition, you may make it dilute suitably the paint for woodworking with thinner etc. at the time of painting.

  Moreover, the coating film thickness by the woodwork coating material is not specifically limited, However, It is desirable to set it as 100-300 micrometers with a dry coating film. That is, when the coating thickness is less than 100 μm, it may be difficult to secure a surface hardness that allows soft wood such as cedar to be used as furniture such as a table top. On the other hand, if the coating film thickness exceeds 300 μm, it may take a great deal of time in the painting work process, increase the cost, and induce various troubles (such as foaming) on the painting.

  Examples of the above woodworking paints include, for example, a two-component polyurethane resin paint, a moisture curable polyurethane resin paint, an oil-modified polyurethane resin paint, an unsaturated polyester resin paint, a UV curable paint, a phthalic resin paint, and an acid curable amino resin. Examples include alkyd resin paints and water-based paints.

  In particular, in a two-pack type polyurethane resin coating, a curing agent mainly composed of a polyisocyanate resin having NCO groups is mixed with a coating material mainly composed of a polyol resin such as polyester, alkyd or acrylic having OH groups. This is a paint that forms a urethane bond and is cured and dried. This two-pack type polyurethane resin coating cures at room temperature and can form a very strong and tough coating film at low cost. Therefore, when a two-component polyurethane resin paint is constructed as the woodwork paint of this embodiment, the best effect can be obtained in increasing the surface hardness of soft wood such as cedar by using it as an undercoat.

  When the woodworking paint of this embodiment is composed of a two-component polyurethane resin paint and is used as an undercoat for soft wood, it preferably has an OH number of 20 to 300 on the polyol side of the paint base, On the polyisocyanate side, TDI, HDI, MDI, IPDI polyisocyanate or mixtures thereof are used. Moreover, the said wood powder is added to a coating material main ingredient. At this time, for product management, it is better that the moisture contained in the wood flour is small. For example, the moisture content is preferably 6% or less. That is, the moisture contained in the wood flour reacts with the polyisocyanate of the curing agent when mixing the paint main agent and the curing agent, which may reduce the degree of urethane bonding and reduce the degree of curing of the resin. For the same reason, wood powder is mixed in the paint base.

  And when coating a two-component polyurethane resin paint, the mixing ratio of the paint main agent and the curing agent is preferably a weight ratio of 1: 1 from the viewpoint of workability, but is not particularly limited, and the desired performance and the like Accordingly, the mixing ratio can be set appropriately.

  As described above, according to the woodworking paint of the above embodiment, a hard coating film that compensates for the surface hardness of soft wood such as cedar is formed by the same painting process as before without special equipment. Is done. This is because when wood powder is added to the woodworking paint, the wood powder forms a three-dimensional network structure in the coating film, increasing the hardness of the coating film and at the same time, the wood of the object to be painted (for example, cedar, etc.) This is thought to be due to improved adhesion to soft wood. As a result, soft wood such as cedar can be effectively used not only for building materials but also for general furniture such as tables, and the range of use of soft wood can be widened.

  In addition, the woodworking paint of this embodiment is effective in that it can exhibit excellent coating performance of a hard material that can supplement its surface hardness when used for painting soft wood, but is not limited to this. It may be applied to hard wood such as oak.

  Next, the present invention will be described in detail by way of examples. In the following examples, a two-component polyurethane resin paint is configured as the woodwork paint. Moreover, the cedar material was used for the soft wood which is the coating object of this two-pack type polyurethane resin paint. This two-component polyurethane resin paint was used for undercoating of cedar.

(Examples 1-7)
The main component and curing agent of the two-component polyurethane resin paint were prepared as follows.
<Main paint>
For the isocyanate curable polyester resin (Dainok D210-80 manufactured by Dainippon Ink & Chemicals, Inc.), wood powder obtained by shaving cedar with an electric saw (the average fiber length of the wood fibers contained in this wood powder is 300 μm, An average fiber thickness of 20 μm) and butyl acetate were added and stirred with a dissolver to prepare a paint base.
<Curing agent>
Ethyl acetate was added to TDI polyisocyanate (Nihon Polyurethane Coronate L) and mixed to prepare a curing agent.
At the time of painting, the above-mentioned paint main agent and curing agent are mixed and used at a weight ratio of 1: 1. Therefore, the amount of wood powder that is 1/2 of the amount of the paint base material mixed is a ratio to the total amount of the two-component polyurethane resin paint.

(Comparative example)
A paint base and a curing agent for a two-component polyurethane resin paint were prepared in the same manner as in the above example except that the wood powder was not added to the paint base. The coating material of the comparative example is also used by mixing the coating agent and the curing agent at a weight ratio of 1: 1 at the time of painting.

  Table 1 below shows the blending amounts of the components of the coating agent and the curing agent in Examples 1 to 7 and Comparative Example. Table 1 also shows the blending ratio of the wood flour with respect to the total amount of the two-component polyurethane resin paint and the nonvolatile content in the total amount of the two-component polyurethane resin paint.

<Creation of cedar (soft wood) paint test board>
For each of the Examples and Comparative Examples, the obtained two-component polyurethane resin paint was applied to a single cedar material with a spray gun at a coating amount of 20 g / (30 cm) ² , and the same paint was applied after 2 hours. The coating was repeated with a spray gun so that the coating amount was 20 g / (30 cm) ² . At this time, coating was performed so that the dry coating thickness of the undercoat was 100 to 300 μm.

Next, 24 hours later, a sanding sealer for intermediate coating (a 2-part polyurethane resin paint of a comparative example with 5 parts by weight of zinc stearate added) was sprayed to a coating amount of 10 g / (30 cm) ^2. It was applied with a gun. After 5 hours, the coated surface was polished with a # 400 sandpaper so that it was flattened, and then the urethane flat of the top coating material (4 parts by weight of a matting agent such as silica was added to the two-component polyurethane resin paint of the comparative example) Was added with a spray gun so that the coating amount was 10 g / (30 cm) ² . Then, it dried for 7 days in the environment of 20-25 degreeC, and obtained the coating test board to a cedar single material.

<Performance evaluation>
About the Example and the comparative example, the coating-film performance evaluation described below was performed with respect to the obtained coating test board.
(1) Nail strength: Evaluated by the degree of biting at the time when the nail of the thumb was bitten into the surface and the nail was damaged when it was felt that the nail would break even if more force was applied. ”And“ 5 ”when the nail hardly bites in, and the evaluation values were taken in 1 to 5 stages.
(2) DuPont dent: Using a JIS K-5600 DuPont impact tester, the depth at which the coating surface was dropped from a height of 30 cm with a load of 300 g was measured with calipers. The tip at this time was a half-inch half-inch.
(3) Pencil hardness: JIS K5600 was evaluated by the presence or absence of a dent.
(4) Coin scratch: The coated surface was strongly pressed and scratched with a 10-yen coin to evaluate whether the indented mark became white. When it became white, it was evaluated as “×”, when it remained transparent, “◯”, and when slightly white, it was evaluated as “Δ”. At this time, scratches on the painted surface were not evaluated.
The above evaluation results are shown in Table 2.

<Evaluation of results>
From Table 2, the DuPont dents are less than half of the comparative examples in Examples 1 to 7, and the surface hardness against the dents due to the force from above is compensated even for soft wood cedar. I understand. In particular, in Examples 4 to 7 in which the content of the wood flour is 10 parts by weight or more, the resistance to dents is remarkably improved even when the cedar is made of soft wood. Moreover, in Examples 1-7, it turns out that the pencil intensity | strength is greatly improved rather than a comparative example, and a surface is hard to be damaged. In particular, in Examples 5 to 7 in which the content of wood powder is 15 parts by weight or more, the surface of the coating film is very hard even if it is a cedar material of soft wood. Moreover, the improvement of the pencil strength in Examples 1-7 is supported also from the test of nail | claw strength and a coin scratch.

As mentioned above, compared with the comparative example which has not added wood flour, the thing of Examples 1-7 has improved the resistance with respect to the force from the top, and even if it is a cedar material of soft wood, it is applied. It can be seen that the hardness on the surface is high. This is because when wood powder is added to the paint for woodworking, the wood powder forms a three-dimensional network structure in the coating film, increasing the hardness of the coating film and at the same time adhesion to the cedar of the object to be coated. This is thought to be due to the improvement of
Therefore, according to the two-component polyurethane resin paints (woodwork paints) of Examples 1 to 7, even a soft wood cedar material can be sufficiently used for furniture such as a table top.

Claims (2)

A woodworking paint that is suitably used for soft wood and has a synthetic resin as a main component,
A woodworking paint containing 0.5 to 25 parts by weight of a wood powder having cellulose fibers having a cellulose structure with respect to the total amount of the woodworking paint. A two-component woodworking paint that is suitably used for undercoating of soft wood, in which a curing agent mainly containing a polyisocyanate resin is mixed with a coating material mainly containing a polyol resin,
A woodworking paint in which wood powder having cellulosic wood fibers is added to the coating material, and the wood powder is contained in an amount of 0.5 to 25 parts by weight based on the total amount of the woodworking paint.