JP6745747B2 - Wood part paint, method of manufacturing wood part paint and method of applying wood part paint - Google Patents

Description

TECHNICAL FIELD The present invention relates to a paint for wood parts containing a plant defibrated fiber and a coating method.

It is known that the wood, which is the object to be coated, does not sufficiently satisfy the durability of the coated film as compared with other objects to be coated (mortar, extruded plate, siding plate, etc.). On the other hand, in Patent Document 1, as a paint for wood, it contains a protective colloid aqueous solution, a lignophenol derivative, and an acrylic emulsion, and improves durability due to the water resistance and weather resistance of the lignophenol derivative. However, an aqueous paint for wood which can be used is described.

Further, it is known that plant defibrated fibers act as a viscosity modifier, an emulsion stabilizer, a water retention agent or an anti-settling agent when they are contained in a paint (resin composition). Patent Document 2 describes an aqueous resin composition containing cellulose nanofibers which are defibrated plants, a copolymer resin and water, and having good fluidity and storage stability.

In addition, although the technical fields are different, Patent Documents 3 and 4 describe surface coating methods for paper and the like containing cellulose nanofibers which are plant defibrated fibers.

JP, 2010-163490, A JP, 2016-033187, A International Publication No. 2007/088974 JP, 2014-050835, A

Wood has a property of absorbing moisture when the humidity is high and releasing water when the humidity is low (moisture absorbing/releasing property), and the wood itself has a property of repeating expansion and contraction (stretchability). The stretchability of the wood itself is not great in terms of its stretch length ratio, but it constantly stretches. For this reason, a coating film formed from a conventional water-based wood coating becomes difficult to follow the expansion and contraction of wood, minute cracks occur over time, water penetrates from the minute cracks, and changes in the surface state There is a problem that discoloration is generated.

Further, conventional aqueous resin compositions containing plant defibrated fibers, even though studied for good fluidity and storage stability, were not expected to be applied to wood. It was For this reason, conventional aqueous resin compositions containing plant defibrated fibers have not been studied up to the discoloration of the coating film when applied to wood.

The present invention has been made in view of the above points, a coating film formed from a paint for wood parts follows the expansion and contraction of the wood itself, thereby suppressing the infiltration of water into the wood, and It is an object of the present invention to provide a wood part paint capable of suppressing discoloration of a wood part coated body to which the part paint is applied.

The xylem coating composition of the present invention is characterized by containing a synthetic resin emulsion and plant defibrated fibers.

According to the wood part paint of the present invention, the wood part paint contains plant defibrated fibers, so that the coating film formed from the wood part paint is reinforced in elongation performance and has the following physical properties. It has an excellent elongation and can follow the expansion and contraction of wood due to moisture absorption and release. For this reason, it is possible to suppress the occurrence of fine cracks in the coating film formed from the paint for wood, it is possible to suppress the infiltration of water into the wood, and suppress the discoloration of the wood-coated body due to the infiltration of water. can do.

Here, in the above-mentioned coating material for xylem, the plant defibrated fibers may be cellulose nanofibers obtained by defibrating plant fibers containing cellulose and hemicellulose. According to this, the coating film formed from the xylem paint, in the film forming process, a network of plant defibrated fibers, that is, cellulose nanofibers is formed, and the coating film formed from the xylem paint is a coating film. Tear strength as a physical property can be made excellent. Therefore, the coating film formed from the paint for wood parts can further suppress the generation of fine cracks, suppress the infiltration of water into the wood, and prevent the discoloration of the wood part coated body due to the infiltration of water. Can be suppressed.

Moreover, in the said coating composition for wood parts, the said plant defibrated fiber can have an average length of 10,000 nm or less and an average width of 200 nm or less.

In addition, in the above-mentioned coating material for wood, the plant defibrated fiber may be a fiber that is defibrated by an enzyme and mechanically defibrated. According to this, the fibrillation of the plant fiber is carried out in combination with the defibration by the enzymatic treatment and the fibrillation by the mechanical treatment, whereby the defibration proceeds more than the defibration by the usual mechanical treatment, and the fibers are finely fibrillated. Can be plant defibrated fiber.

Further, in the above-mentioned paint for xylem, the plant defibrated fibers may be multi-branched. According to this, although the coating material for wood is excellent in elongation as a coating film physical property, since the plant defibrated fiber does not affect the viscosity of the coating for wood, it is excellent in handleability as a paint. Can be something.

Further, the above-mentioned paint for wood parts can be used for outdoor use. According to this, the coating film formed from the coating material for a wood part is excellent in the improvement of elongation and the effect of suppressing discoloration. Therefore, even for outdoor use, the wood-part paint can appropriately protect the wood part coated with the wood-part paint, and can suppress discoloration of the wood-part coated body.

Further, the coating method of the present invention is a method for coating a wood portion, and may include a coating step of applying the above-mentioned wood portion paint. According to this, a coating film formed from a coating material for xylem does not contain VOC (volatile organic compound) except that the coating material for xylem is contained in an additive such as a viscosity modifier. It has excellent elongation as a physical property. For this reason, the coating method of the present invention can protect the wood-coated body on which the wood-based paint is applied, while being friendly to the natural environment.

Further, the coating method of the present invention is a method for coating wood parts, in which a pretreatment step of applying a pretreatment agent containing a plant defibrated fiber dispersion liquid and a coating method of applying a paint containing a synthetic resin emulsion are performed. And a process. According to this, since the plant defibrated fiber dispersion is applied as a pretreatment before the coating process of the coating material containing the synthetic resin emulsion, the coating film formed from the coating material has enhanced elongation performance and physical properties of the coating film. The elongation rate is excellent. Therefore, the coating method of the present invention, the coating film formed from the coating material for wood, suppresses the generation of fine cracks, suppresses the infiltration of water into the wood, the wood coating body with the infiltration of water. Since it suppresses the discoloration of the wood, the wood can be painted with excellent durability.

According to the wood part paint of the present invention, a coating film formed from the wood part paint has excellent elongation as a coating film physical property and can follow the expansion and contraction of the wood itself. The painted wood part can be prevented from entering water and can be prevented from being discolored due to a change in surface condition.

It is an image figure of network formation of the cellulose nanofiber of the coating material for xylem of the present invention.

Hereinafter, embodiments of the present invention will be described. The wood coating composition of the embodiment is characterized by containing a synthetic resin emulsion and plant defibrated fibers.

The wood to which the wood coating is applied absorbs moisture when the humidity is high and releases water when the humidity is low (moisture absorption and release), and the property that the wood itself repeatedly expands and contracts (stretchability) And have. For this reason, a coating film formed from the wood part paint is required to have breathability corresponding to moisture absorption and desorption and extensibility corresponding to elasticity. The air permeability is satisfied by the air holes generated in the film forming process of a coating film if it is a coating film formed from a coating material containing a synthetic resin emulsion as a binder. This vent hole is a very small one that does not allow water to enter from the outside. The inventors of the present application have found that extensibility is satisfied when the coating material for xylem contains plant defibrated fibers. The wood-part paint of the embodiment has a synthetic resin emulsion, a defibrated fiber, and other additives to provide a coating film formed from the wood-part paint with air permeability and extensibility. You can As a result, the coating film formed from the paint for wood can suppress the generation of fine cracks, suppress the infiltration of water into the wood, and suppress the discoloration of the wood-coated body due to the infiltration of water. You will be able to.

A synthetic resin emulsion is a suspension (in which fine particles of a synthetic resin obtained by polymerizing a plurality of kinds of monomers (monomers) with a polymerization initiator to form a copolymer are dispersed in water by a surfactant (emulsifier) ( Emulsion). The synthetic resin emulsion forms a binder as a binder for the coating film by evaporating water, which is a medium, to fuse fine particles of the synthetic resin to form a film. The synthetic resin emulsion has air permeability ensured by the air holes through which water generated during the film formation process volatilizes. In addition, the paint for xylem containing a synthetic resin emulsion as a binder does not contain VOC (volatile organic compound) except water contained in an additive such as a viscosity modifier, as a medium. It can be environmentally friendly.

As the synthetic resin emulsion, a vinyl acetate emulsion, an ethylene vinyl acetate emulsion, an acrylic emulsion, an acrylic styrene emulsion, an acrylic silicone emulsion, an acrylic urethane emulsion, or the like can be used depending on the resin composition. Among these, acrylic emulsions, acrylic styrene emulsions, acrylic silicone emulsions, and acrylic urethane emulsions have excellent water resistance and can be preferably used. Furthermore, acrylic emulsions, acrylic silicone emulsions, and acrylic urethane emulsions have excellent weather resistance in addition to water resistance, and thus can be more preferably used.

The average particle size of the synthetic resin emulsion is preferably 50 to 500 nm. This is because the ventilation holes through which water generated in the film formation process of the synthetic resin emulsion volatilizes ensure the air permeability, and the coating composition for wood containing the synthetic resin emulsion can have excellent storage stability. .. When the average particle diameter of the synthetic resin emulsion is less than 50 nm, the resin film formed from the synthetic resin becomes dense and air permeability may not be secured. On the other hand, when the average particle diameter exceeds 500 nm, the synthetic resin emulsion becomes unstable, and the storage stability of the wood coating material containing the synthetic resin emulsion as a binder may be poor. More preferably, the average particle diameter of the synthetic resin emulsion is 100 to 300 nm.

The glass transition temperature (Tg) of the synthetic resin of the synthetic resin emulsion is preferably -20 to 5°C. Synthetic resin has flexibility that can follow the expansion and contraction of wood as a binder for a coating film formed from a paint for wood, and due to its moderate flexibility, little dirt adheres to the coating film. This is because the aesthetics of When the Tg of the synthetic resin is lower than -20°C, the binder of the coating film formed from the wood coating material becomes soft, and foreign matter such as dust is liable to adhere to the coating film, and the appearance of the coating film may not be maintained. On the other hand, when Tg is higher than 5° C., the binder of the coating film formed from the wood coating becomes hard, and the synthetic resin follows the expansion and contraction of wood as the binder of the coating film formed from the wood coating. However, the coating film may have fine cracks, and water may penetrate through the fine cracks, which may deteriorate the discoloration resistance. More preferably, the Tg of the synthetic resin is −15 to 0° C., and even more preferably, the Tg is −10 to −5° C. The Tg can be adjusted by adjusting the type and amount of the monomer used. The Tg can be obtained from a calculation formula of Fox (FOX) (formula (1) below). Wi represents the mass fraction of the monomer i, Tgi represents the Tg (° C.) of the monomer i, and the Tg of the monomer is the value described in Polymer Handbook (John Wiley & Sons). Known values such as can be used.

1/(273+Tg)=Σ(Wi/(273+Tgi)) (1)

The synthetic resin emulsion can be produced by using a general polymerization method. An example of the polymerization method is a pre-emulsion emulsion dropping polymerization method. The pre-emulsion emulsion dropping polymerization method is to prepare a pre-emulsion emulsion by stirring a monomer, a surfactant and water at a high speed, and to water adjusted to around 80° C. which is a place of polymerization, and a pre-emulsion emulsion. This is a method in which a polymerization initiator composed of a peroxide is added dropwise with stirring over about 100 minutes to polymerize. The combination of monomers can be selected depending on the resin composition and Tg. The synthetic resin emulsion may be a commercially available product. As a commercially available synthetic resin emulsion, an acronal series (manufactured by BASF Japan Co., Ltd.), a polytron series (manufactured by Asahi Kasei Chemicals Co., Ltd.), an AE series (manufactured by E-Tech Co., Ltd.) and the like can be used.

The plant defibrated fiber is a fiber in which bleached pulp processed from a plant is defibrated by an enzyme and mechanically defibrated. Bleached pulp processed from plants is pulp (plant fibers) obtained by digesting and bleaching plants (plant chips).

The plant from which the plant fiber is collected is not particularly limited, and examples thereof include conifers such as cedar and cypress, broad-leaved trees such as zelkova and oak, and herbs such as rice and millet. Among these, conifers and herbs that can be easily mechanically defibrated can be preferably used, and since conifers have a high yield of plant defibrated fibers, they can be more preferably used.

The plant defibrated fiber is made from a bleached pulp processed from a plant as a raw material, and the bleached pulp is a pulp (plant fiber) obtained by cooking and bleaching a plant (plant chip). The digestion of plants is to dissolve the plant fibers (pulping) by immersing the plant chips in an aqueous solution of caustic soda and performing heat treatment. For bleaching, plant fibers can be bleached by using a general bleaching method such as peracetic acid bleaching, oxygen bleaching, sodium hypochlorite bleaching, ozone bleaching and the like.

The plant defibrated fiber is a fiber in which bleached pulp processed from a plant is defibrated by an enzyme and mechanically defibrated. The fibrillation of the vegetable fiber is carried out in combination with the defibration by the enzyme treatment and the fibrillation by the mechanical treatment, whereby the fibrillation proceeds more than the defibration by the usual mechanical treatment, and the fiber can be finely fibrillated.

The defibration by the enzyme treatment is to defibrate the bleached pulp with an aqueous solution containing an enzyme so that the average fiber length is 1,000 to 100,000 nm and the average fiber width is 3 to 500 nm. .. As an example of the enzyme used for defibration, cellulase (XL), cellobiohydrolase (CBH), endoglucanase (EG), β-glucosidase (BGL) and the like can be used. Among these, cellulase or endoglucanase, which are excellent in fiber disintegration efficiency, can be more preferably used.

In mechanical defibration, bleached pulp defibrated by an enzyme is defibrated using a mechanical defibration machine such as a bead mill (ball mill), and the average fiber length is 100 to 10,000 nm and the average fiber width is 1 It is a multi-branched plant defibrated fiber having a size of ˜200 nm. Since the average length of the defibrated fiber is 100 to 10,000 nm, the coating material for wood part containing the defibrated fiber is excellent in handleability of the coating material and excellent in elongation as a coating film physical property. Is. When the average length of the plant defibrated fibers is less than 100 nm, the elongation as a coating film physical property may be poor. However, it does not cause cracks in the coating film and does not deteriorate the discoloration resistance of the wood-coated body. On the other hand, when the average length of the defibrated plant fibers exceeds 10,000 nm, the viscosity of the wood-part coating material becomes high, and the handleability may be poor. More preferably, the average length of the defibrated fibers is 500 to 5,000 nm. Regarding the average length of plant defibrated fibers, the longer the defibration time by the mechanical defibrator, the shorter the average length of the fibers. The average fiber length with respect to the defibration time of the mechanical defibrator differs depending on the individual individual defibrators. Therefore, the adjustment of the average length of the plant defibration fiber, to create a calibration curve of the average length of the fiber for the defibration time by the mechanical defibration machine in advance, from the calibration curve for the average length of the required fiber The defibration time can be obtained and adjusted. The average length (width) of the plant defibrated fibers was obtained by photographing the sample defibrated fibers using a stereoscopic microscope or an electron microscope and measuring 100 of the photographed images to determine the average value. The plant defibrated fiber is preferably a multi-branched plant defibrated fiber. A coating film formed from a paint for wood part containing a multi-branched plant defibrated fiber is easily entangled with the multi-branched plant defibrated fiber and coating film components, so that the tensile strength is reinforced and the physical properties of the coating film are This is because the tear strength can be excellent. The plant defibrated fiber is apt to be hyperbranched by the combined use of defibration by enzyme treatment and defibration by mechanical treatment. And the width of the plant defibrated fiber is preferably 1 to 200 nm. This is because the plant defibrated fibers in this width have many branches due to multi-branching, and it is easy to form a network of cellulose nanofibers described later. More preferably, the width of the defibrated plant fibers is 3 to 100 nm.

The plant defibrated fiber is preferably a cellulose nanofiber obtained by defibrating a plant fiber containing cellulose and hemicellulose. According to this, in the film forming process of the coating film formed from the wood part paint, the plant defibrated fibers form a network of cellulose nanofibers and are formed from the wood part paint as shown in FIG. The coating film may have excellent tear strength as a coating property. Therefore, the coating film formed from the paint for wood parts can further suppress the generation of fine cracks, suppress the infiltration of water into the wood, and prevent the discoloration of the wood part coated body due to the infiltration of water. It can be suppressed. It is assumed that the network of cellulose nanofibers is formed by connecting cellulose and hemicellulose by the hydrophobic and hydrophilic functional groups of hemicellulose.

When plant defibrated fiber is contained in a paint for wood, it forms a fine network in the paint, and the elongation performance of the paint film formed from the paint for wood is reinforced, and the elongation as a physical property of the paint is improved. It has a high rate and can follow the expansion and contraction of wood due to moisture absorption and release. Further, since the plant defibrated fiber stabilizes the interface of the coating film and the interface of the wood base, the wood-coated body coated with the wood-based paint can suppress the infiltration of water, and the surface condition It is possible to suppress the discoloration due to the change of.

The content of the plant defibrated fiber in the paint for wood is preferably 0.1 to 5 mass% in terms of nonvolatile content. This is because it is possible to improve the elongation as a physical property of the coating film without deteriorating the viscous handleability of the paint for wood parts. If the content of plant defibrated fibers in the coating material for wood is less than 0.1% by mass, the elongation as a coating film physical property may not be sufficiently improved. On the other hand, if it exceeds 5% by mass, the viscosity of the coating material for wood parts tends to be high, resulting in poor handleability. More preferably, the defibrated fiber content of the paint for xylem is 0.2 to 2% by mass, and further preferably 0.5 to 1.5% by mass.

Other additives may be contained in the wood part paint, if necessary. Other additives include wetting agents, dispersants, viscosity modifiers, defoamers, antifreezing agents, antiseptics, antifungal agents, antialgae agents, film-forming aids, plasticizers, color pigments, extender pigments, dyes, and luster. There are erasers. It is necessary to select and use these additives that do not reduce the elongation of the coating film formed from the wood part paint and do not impair the weather resistance. In particular, since the color pigment sometimes impairs the weather resistance (discoloration resistance) of the coating film depending on its type, it is preferable to use an inorganic color pigment that is difficult to inhibit the weather resistance of the coating film.

The wood part paint can be produced by mixing a synthetic resin emulsion, plant defibrated fiber, other additives and diluting water. For the mixing, a stirrer such as a general-purpose mixer or dissolver can be used so that the plant defibrated fibers and the like are uniformly dispersed.

The wood part can be painted by using a general-purpose paint tool such as a spray, a roller or a brush. Immediately after coating, the coating surface (coating film) can be wiped and rubbed with a cloth to give a uniform thickness, and the coating film formed from the wood coating has an elongation as a coating property. Can be better.

Next, as a second embodiment, as a pretreatment step, a mode in which the plant defibrated fiber dispersion liquid is applied to the wood as a pretreatment agent and a coating material containing no plant defibrated fibers is applied will be described.

The second embodiment, as a pretreatment step when applying a coating material containing a synthetic resin emulsion, by applying a plant defibrated fiber dispersion, to enhance the elongation performance of the coating film formed from the coating material, It is intended to improve the elongation as a physical property of the coating film. Since the plant defibrated fiber dispersion (pretreatment agent) does not contain a binder component, when the coating containing the synthetic resin emulsion after applying the pretreatment agent is applied, the plant defibrated fibers are integrated with the coating. Turn into. The plant defibrated fiber forms a fine network in the paint and reinforces the elongation performance of the formed coating film. Moreover, since the plant defibrated fiber stabilizes the interface of the coating film and the interface of the wood base, the wood-coated body coated by the method of the second embodiment can suppress the infiltration of water, It is possible to suppress discoloration associated with a change in surface condition. Incidentally, the stabilization, because the plant defibrated fiber has hemicellulose, by the hydrophobic and hydrophilic functional groups of hemicellulose, the plant defibrated fiber is easy to integrate with the paint, easy to be familiar with the wood base It is supposed that.

Hereinafter, the present invention will be described in more detail with reference to examples. In the example, the coating for wood is made to contain plant defibrated fibers and is applied to xylem as the first embodiment. As a pretreatment step, a plant defibrated fiber dispersion (pretreatment agent) is applied to xylem. However, a form in which a paint containing no plant defibrated fiber is applied will be described as a second embodiment. The test examples 2 to 13, 15, 16, 22 to 33, 35 and 36 are examples, and the test examples 1, 14, 21 and 34 are comparative examples.
<First Embodiment>
The first embodiment is a test piece obtained by coating wood (cedar wood, hemlock wood) with a wood part paint (paints 1 to 13) containing a synthetic resin emulsion and plant defibrated fibers. is there.

The processing of the plant defibrated fiber was performed as follows. Sugi chips were used as a raw material for the plant defibrated fiber, and the sugi chips were digested and bleached to obtain bleached pulp (vegetable fiber). Then, different defibration was applied to the bleached pulp to prepare a plurality of types of plant defibrated fibers. Specifically, the plant defibrated fibers were obtained by subjecting bleached pulp to defibration with different enzymes and mechanical defibration to obtain plant defibrated fibers CNF2-4 and CNF6-8. Table 1 shows the conditions for defibration and mechanical defibration of CNF2-4 and CNF6-8 by enzymes. CNF2 is a plant defibrated fiber that has been mechanically defibrated without being enzymatically defibrated. Note that these plant defibrated fibers are cellulose nanofibers containing cellulose and hemicellulose. In addition, in the description of the enzyme types in Table 1, EG is endoglucanase and XL is cellulase XL-531.

Enzymatic defibration is performed by immersing bleached pulp in an enzyme solution of the concentration and type shown in Table 1, and mechanical defibration is performed using a bead mill (zirconia bead mill) under the conditions (time) shown in Table 1. And defibrated.

The wood part paint was prepared as follows. The paints for wood parts were prepared by changing the types of plant defibrated fibers (CNF2-4, CNF6-8) and the compounding amounts thereof to prepare paints 1-13 having the compositions shown in Table 2. The characteristics of the raw materials in the formulations listed in Table 2 are listed below. Synthetic resin emulsion (acrylic silicone emulsion, Tg: -8°C, nonvolatile content: 45%, average particle diameter: 200 nm, viscosity: 800 mPa·s), defoaming agent (ether-based defoaming agent, nonvolatile content: 20%) , Wetting agent (nonionic surfactant-based wetting agent, nonvolatile content: 20%), color pigment (inorganic coloring pigment mixture, nonvolatile content: 50%).

In the test example, a coating material 1 to 13 was applied to a material made of cedar wood or Tsuga wood under the conditions shown in Table 3 to prepare a test body. Although not shown in Table 3, the coating amount of the coating material for wood part is 80 g/m ² for the first time and 60 g/m ² for the second time in common. An accelerated weather resistance test (JIS K 5600-7-7: xenon weatherometer method) assuming outdoor use was performed on these coated test bodies to evaluate the weather resistance. The weather resistance was evaluated by obtaining the color difference (JIS Z 8730:2000: color display method-color difference of object color) before and after the accelerated weathering test of 1,000 hours. The color difference ΔE ^* ab is less than 2.0, ⊚, the color difference ΔE ^* ab is more than 2.0 and less than 4.0, the one is 4.0 or more and less than 5.0, and the more than 5.0. Was evaluated as x. The larger the numerical value of the color difference ΔE ^* ab is, the more the color difference before and after the test occurs (discoloration), and the color difference ΔE ^* ab of less than 5.0 was regarded as the effect of suppressing discoloration. The color difference ΔE ^* ab was obtained from a calculation formula (Equation (2) below) by measuring the L ^* a ^* b ^* color specification using a commercially available colorimeter. In addition, ΔL ^* is a difference between L ^* before and after the test, Δa ^* is a difference between a ^* before and after the test, and Δb ^* is a difference between b ^* before and after the test.

ΔE ^* ab=((ΔL ^* ) ² +(Δa ^* ) ² +(Δb ^* ) ² ) ^1/2 ...(2)

Test Example 1 is a test example in which the coating material 1 containing no plant defibrated fiber was applied to a material made of cedar wood. Since the paint 1 is a wood part paint containing no plant defibrated fiber, the discoloration suppressing effect could not be confirmed. It is presumed that the coating film formed from the coating material 1 was not reinforced in the elongation performance, did not satisfy the elongation rate as the physical properties of the coating film, and had fine cracks. Then, it is considered that water penetrated into the wood-coated body through minute cracks and discoloration occurred due to the change of the surface condition.

Test examples 2 to 13 are test examples in which paints 2 to 13 containing plant defibrated fibers subjected to different defibration conditions were applied to a material made of cedar wood. These had a discoloration suppressing effect. Since the paints 2 to 13 are wood part paints containing plant defibrated fibers, the coating film formed from these has enhanced elongation performance and satisfies the elongation rate as the physical properties of the coating film. It is considered that the infiltration of water into the water was prevented and discoloration was suppressed in the evaluation of weather resistance.

Test Example 14 is a test example in which the coating material 1 containing no plant defibrated fiber was applied to a material made of Tsuga material. Since the paint 1 was a wood part paint containing no plant defibrated fiber, it did not have a discoloration suppressing effect as in Test Example 1. It is presumed that the coating film formed from the coating material 1 was not reinforced in the elongation performance, did not satisfy the elongation rate as the physical properties of the coating film, and had fine cracks. Then, it is considered that water penetrated into the wood-coated body through minute cracks and discoloration occurred due to the change of the surface condition.

Test examples 15 and 16 are test examples in which coating materials 4 and 5 containing plant defibrated fibers were applied to a material made of Tsuga material. These had a discoloration suppressing effect. Since the paints 4 and 5 are wood part paints containing plant defibrated fibers, the coating film formed from this has enhanced elongation performance and satisfies the elongation rate as the physical properties of the coating film. It is considered that the infiltration of water was prevented and discoloration was suppressed in the evaluation of weather resistance.
<Second Embodiment>
In the second embodiment, the plant fibrillated fiber dispersion liquid (pretreatment agent) shown in Table 4 is applied to the xylem as a pretreatment step, and a coating 1 containing no plant defibrated fiber (Paint 1 shown in Table 2 is used. ) Is applied to make a test body. The plant defibrated fibers CNF2-4 and CNF6-8 described in Table 4 are the same as those described in Table 1, and the pretreatment agent contains these plant defibrated fibers in content (wt %). It was adjusted by diluting with water so that the values would be the same.

In the test example, the pretreatment agents 2 to 4 and 6 to 8 shown in Table 4 were applied to a material made of cedar wood or Tsuga wood, and the paint 1 shown in Table 2 was applied under the conditions shown in Table 5. And made it a test body. Although not shown in Table 5, in common, the coating amount of the pretreatment agent was 150 g/m ² for both the first and second treatments, and the coating amount for the wood part was the same for the first treatment. It is 80 g/m ² and the second time is 60 g/m ² .

With respect to these coated test bodies, an accelerated weather resistance test was performed in the same manner as in the first embodiment to evaluate the weather resistance.

Test Example 21 is the same as Test Example 1 described above, and is a test example in which the pretreatment agent was not applied to the material made of cedar wood and the coating material 1 containing no plant defibrated fiber was applied. Since the paint 1 is a wood part paint containing no plant defibrated fibers and no pretreatment agent was applied, the discoloration suppressing effect could not be confirmed. It is presumed that the coating film formed from the coating material 1 was not reinforced in the elongation performance, did not satisfy the elongation rate as the physical properties of the coating film, and had fine cracks. Then, it is considered that water penetrated into the wood-coated body through minute cracks and discoloration occurred due to the change of the surface condition.

Test examples 22 to 33 are test examples in which a pretreatment agent was applied to a material made of cedar wood by changing the type and the number of times of application, and the coating material 1 containing no plant defibrated fiber was applied, and the effect of suppressing discoloration was confirmed. did it. Although the paint 1 is a wood part paint that does not contain plant defibrated fibers, a pretreatment agent that contains plant defibrated fibers is applied as a pretreatment. For this reason, the plant defibrated fiber of the pretreatment agent is dissolved in the solvent of the paint, the plant defibrated fiber is mixed and integrated with the paint, the formed coating film has enhanced elongation performance, It is considered that the elongation was satisfied, the infiltration of water into the wood-coated body was prevented, and the discoloration was suppressed in the evaluation of weather resistance.

Test Example 34 is the same as Test Example 14 described above, and is a test example in which the pretreatment agent was not applied to the material made of Tsuga material and the coating material 1 containing no plant defibrated fiber was applied, and the discoloration suppressing effect was obtained. Could not be confirmed. Since the coating material 1 is a coating material for wood parts that does not contain defibrated fibers and is not coated with a pretreatment agent, the coating film formed from this coating does not have enhanced elongation performance and has an elongation rate as coating film physical properties. It is presumed that it was not satisfied and fine cracks had occurred. Then, it is considered that water penetrated into the wood-coated body through minute cracks and discoloration occurred due to the change of the surface condition.

Test Examples 35 and 36 are test examples in which the pretreatment agent was applied to the material made of Tsuga material with a different number of times of application and the coating material 1 containing no plant defibrated fiber was applied, and the effect of suppressing discoloration can be confirmed. It was Although the coating material 1 is a wood part coating material containing no plant defibrated fibers, a pretreatment agent containing plant defibrated fibers is applied as a pretreatment, and thus the coating film formed from these is Test Example 22. Similar to No. 33, the elongation performance is reinforced, the elongation as a coating film physical property is satisfied, water is prevented from entering the wood-coated body, and discoloration is suppressed in the evaluation of weather resistance. Conceivable.

Claims (8)

A synthetic resin emulsion, and a wood part paint containing plant defibrated fibers ,
The content of the plant defibrated fiber is 0.1 to 5 mass% in terms of nonvolatile content,
The glass transition temperature (Tg) of the synthetic resin of the synthetic resin emulsion is −20 to 5° C.,
A paint for wood, which is characterized by not containing an extender pigment . The average particle diameter of the said synthetic resin emulsion is 50-500 nm, The coating material for the wood part of Claim 1 characterized by the above-mentioned. Said plant fibrillated fibers, wherein the plant fibers containing cellulose and hemicellulose Ri cellulose nanofibers der that is defibrated, average length 10,000nm or less, the average width and wherein the at 200nm or less Item 1. A paint for wood parts according to item 1. The coating composition for xylem according to claim 1, wherein the plant defibrated fibers are multi-branched. The paint for wood parts according to claim 1, which is for outdoor use. The method for producing a paint for xylem according to claim 1, wherein the synthetic resin emulsion and the defibrated fiber are mixed.
The plant defibrated fiber is a fiber for producing a paint for xylem, characterized in that the bleached pulp is defibrated by an enzyme, and the bleached pulp defibrated by the enzyme is a mechanically defibrated fiber. The said enzyme is cellulase (XL) or endoglucanase (EG), The manufacturing method of the wood coating material of Claim 6 characterized by the above-mentioned. A method of coating the xylem, the method for coating a wood coating material characterized in that it comprises a coating step of applying a wood paint according to claim 1.

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