Wood substrate, decorative material and manufacturing method thereof

Abstract

To provide a woody base material free from a harmful substance that might act as a potential cause of a sick house syndrome, and having practical water proofness, a decorative material equipped with the woody base material and a manufacturing method of the woody base material.SOLUTION: A woody base material 10 includes: a woody material 4 having at least one of forms of powder and chip; and a thermoplastic resin composition 5. A standardization C-H area calculated using an expression (1) from an absorption spectrum obtained at a Fourier-type infrared spectroscopic measurement is within a range of 0.07 to 1.00: A standardization C-H area=SC-H / (SO-H+SC-OH) ... (1). In the expression (1), SC-H is a peak area value derived from a CH2 group and a CH3 group, SO-H is a peak area value derived from an OH group and SC-OH is a peak area value derived from a C-OH group, respectively.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wood substrate, a decorative material, and a method for manufacturing a wood substrate. [Background technology]

[0002] Wood substrates are made by heating and pressurizing a mixture of wood materials such as wood flour, wood chips, and wood fiber with an adhesive. These wood substrates are called particle boards, medium-density fiberboards, etc., depending on the type of wood material, and are used in a wide range of applications, including as underlayment for floors and walls, as well as for building materials and furniture.

[0003] Conventionally, adhesives for wood substrates have been made using urea resin adhesives, melamine resin adhesives, or phenol resin adhesives, along with curing agents containing formaldehyde. Formaldehyde is a harmful substance that can cause sick building syndrome, so its emission from wood substrates has become a problem, and various measures to reduce the amount of emission have been considered. However, with conventional technologies, it has been difficult to completely suppress formaldehyde emission.

[0004] In response to this, a method has been proposed in the past for producing fiberboards by using an adhesive whose main components are powdered sugars and powdered polycarboxylic acids as formaldehyde-free adhesives, mixing this with plant fibers, and molding it under heat and pressure (see paragraph

[0017] of Patent Document 1).Also, a method has been proposed for producing laminates containing wood substrates using an adhesive consisting of polyvinyl alcohol and water as a formaldehyde-free adhesive (see paragraph

[0015] and Figure 1 of Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-55620 [Patent Document 2] Patent No. 5553279 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the wood substrates using the above-mentioned conventional adhesives are not practically sufficient in terms of mechanical properties such as bending strength and water resistance. Therefore, an object of the present invention is to provide a wood substrate that does not contain harmful substances that cause sick house syndrome and has practical water resistance, a decorative material that includes this wood substrate, and a method for manufacturing this wood substrate. [Means for solving the problem]

[0007] A wood substrate according to one embodiment of the present invention comprises a wood material in at least one of powder and chip form and a thermoplastic resin composition, and is characterized in that the normalized C-H area calculated from the absorption spectrum obtained by Fourier infrared spectroscopy using the following formula (1) is in the range of 0.07 to 1.00. Standardized CH area=S C-H / (S O―H +S C-OH )...Equation (1)

[0008] Here, in equation (1), S C-H Wavenumber: 2700-3000cm -1 The area value of the peaks derived from the CH2 and CH3 groups in the vicinity, S O-H is a wave number of 3000-3500 cm -1 The area value of the peak derived from the OH group in the vicinity, S C-OH Wavenumber: 900-1200cm -1 The area values ​​of the peaks derived from the C-OH groups in the vicinity are shown.

[0009] Furthermore, a wood substrate according to one aspect of the present invention is characterized in that the normalized CH area is in the range of 0.08 to 0.35. Furthermore, a wood substrate according to one embodiment of the present invention is characterized in that the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) is within the range of 95 / 5 to 70 / 30.

[0010] Furthermore, a wood substrate according to one embodiment of the present invention is characterized in that the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) is within the range of 85 / 15 to 70 / 30. Furthermore, a wood substrate according to one aspect of the present invention is characterized in that the wood material contains a mushroom bed as a raw material.

[0011] Furthermore, a wood substrate according to one aspect of the present invention is characterized in that the thermoplastic resin composition contains polyethylene. In addition, a wood substrate according to one aspect of the present invention is characterized in that the thermoplastic resin composition contains an acid-modified polyolefin. Furthermore, a wood substrate according to one embodiment of the present invention is characterized in that the content of the acid-modified polyolefin is in the range of 3 to 40 parts by mass per 100 parts by mass of the total thermoplastic resin composition.

[0012] A decorative material according to one aspect of the present invention is characterized in that it comprises the above-mentioned wood substrate and a decorative substrate laminated thereon.

[0013] A method for producing a wood substrate according to one embodiment of the present invention includes a step of heating and pressurizing a raw material mixture containing a wood material in at least one of powder and chip form and a powdered thermoplastic resin composition to form a wood substrate. The wood substrate is characterized in that the normalized C-H area, calculated from the absorption spectrum obtained by Fourier transform infrared spectroscopy using the following formula (1), is in the range of 0.07 to 1.00. Standardized CH area=S C-H / (S O―H +S C-OH )...Equation (1)

[0014] Here, in equation (1), S C-H Wavenumber: 2700-3000cm -1 The area value of the peaks derived from the CH2 and CH3 groups in the vicinity, S O-H is a wave number of 3000-3500 cm -1 The area value of the peak derived from the OH group in the vicinity, S C-OHWavenumber: 900-1200cm -1 The area values ​​of the peaks derived from the C-OH groups in the vicinity are shown.

[0015] In addition, in one embodiment of the present invention, the method for producing a wood substrate is characterized in that the step of producing the powdered thermoplastic resin composition includes the steps of kneading multiple types of thermoplastic resin compositions by an extrusion method, and pulverizing the kneaded thermoplastic resin composition to form a powder. [Effects of the Invention]

[0016] According to one aspect of the present invention, it is possible to provide a wood substrate that does not contain harmful substances that cause sick building syndrome and has practical water resistance, a decorative material that includes this wood substrate, and a method for manufacturing this wood substrate. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram illustrating a method for manufacturing a wood substrate according to an embodiment of the present invention. FIG. [Figure 2] 1 is a schematic cross-sectional view showing the structure of a wood substrate according to a first embodiment of the present invention. [Figure 3] This is the infrared absorption spectrum of a typical wood material. [Figure 4] 1 shows an infrared absorption spectrum of a wood base material according to a first embodiment of the present invention. [Figure 5] FIG. 3 is a schematic cross-sectional view showing the structure of a decorative material according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc., differ from the actual ones. Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the materials, shapes, structures, etc. of the components to those described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims.

[0019] [First embodiment] A schematic diagram illustrating a method for manufacturing a wood substrate according to an embodiment of the present invention is shown in Figure 1. A metal plate 2 is placed on the bottom of a jig 1 for manufacturing a wood substrate, which has a storage compartment cut out to a predetermined size (for example, a 10 cm x 10 cm square), and a release film 3 is placed on top of that.

[0020] Next, a raw material mixture 6 containing a wood material 4 in at least one of powder and chip form and a powdered thermoplastic resin composition 5 is placed in the storage section of the wood substrate manufacturing jig 1, and a release film 3 is placed on the raw material mixture 6. Next, a thickness adjusting metal plate 7 is placed on the jig 1 for manufacturing a wooden substrate, and the raw material mixture 6 is pressed down from above with a metal weight 8 via a release film 3 .

[0021] Finally, a press top plate 9 set under predetermined conditions is heated and pressurized from above the raw material mixture 6 via a metal weight 8, forming the wood substrate 10 according to this embodiment. FIG. 2 is a schematic cross-sectional view showing the structure of the wood substrate 10 according to this embodiment. The wood substrate 10 is called particle board, medium density fiberboard, or the like depending on the type of wood material 4, and is used in a wide range of applications such as underlayment for floors and walls, fittings, and furniture.

[0022] The wood base material 10 does not contain harmful substances such as formaldehyde that cause sick house syndrome, and therefore the emission of harmful substances such as formaldehyde that cause sick house syndrome from within the wood base material 10 can be suppressed. The wood material 4 and the thermoplastic resin composition 5 that constitute the wood substrate 10 will be described below.

[0023] (wood material 4) The wood material 4 is in the form of at least one of powder and chips. Here, the terms "powder" and "chip" do not generally have definitions for size or shape. In this embodiment, they refer to a material having a size (average particle size) ranging from several tens of microns to several centimeters. To ensure stable production of the wood substrate 10, it is desirable for the average particle size of the wood material 4 to be in the range of 1 to 5 mm.

[0024] Examples of the wood material 4 include wood flour, wood fiber, and wood crushed into chips, and examples of the raw material include thinned wood, sawdust, and waste wood. Furthermore, materials other than wood can also be used as the wood material 4, such as bamboo, hemp, coconut fiber, and walnut shells, as long as they contain cellulose components similar to wood.

[0025] A suitable raw material for the woody material 4 is, for example, used mushroom beds, which are generated in large quantities during mushroom cultivation. A mushroom bed is a culture medium used for mushroom cultivation, and is made by mixing wood chips and sawdust with nutrients such as wheat bran and rice bran. It is estimated that around 300,000 tons of mushroom beds are discarded annually in Japan after mushroom cultivation, making them a promising source of biomass, but recycling is currently not progressing well. Therefore, using these as a woody raw material (woody material 4) would be beneficial in reducing the environmental burden.

[0026] As for the wood substrate 10 containing a mushroom bed, the mushroom bed may be used alone as the wood material 4, or the mushroom bed may be mixed with other wood materials 4. Here, "wood substrate containing a mushroom bed" means a wood substrate 10 in which the proportion of the mushroom bed to the volume of the entire wood material 4 is in the range of 1% to 100%.

[0027] (Manufacturing method of wood material 4) For example, when attempting to obtain wood material 4 from waste wood, it contains many foreign objects such as concrete fragments, metal fragments, and paper. Foreign objects can be removed by known methods, such as magnetic sorting, air sorting, and gravity sorting. Furthermore, large particles are adjusted in size by known methods, such as cutting and crushing, to generally be in the range of several tens of microns to several centimeters. To ensure stable production of wood substrate 10, it is desirable for the average particle size of wood material 4 to be in the range of 1 to 5 millimeters. Furthermore, when attempting to obtain the wood material 4 from a mushroom bed, it is preferable to sterilize it using a known method before use.

[0028] (mass ratio of wood material 4 to thermoplastic resin composition 5) The mass ratio of the wood material 4 to the thermoplastic resin composition 5 (wood material / thermoplastic resin composition) is preferably in the range of 95 / 5 to 70 / 30. If the content of the wood material 4 is greater than the above value (95 / 5), sufficient bending strength cannot be imparted to the wood base material 10. On the other hand, if the content of the wood material 4 is less than the above value (70 / 30), the wood base material 10 is likely to deform when heated and pressurized, which is undesirable.

[0029] The mass ratio of the wood material 4 to the thermoplastic resin composition 5 (wood material / thermoplastic resin composition) is more preferably in the range of 85 / 15 to 70 / 30. By keeping the content of the wood material 4 within the above range, a wood substrate 10 with greater bending strength can be obtained. The wood base material 10 may be made up of two or more layers, rather than a single layer, and the mass ratio of the wood material 4 to the thermoplastic resin composition 5 may be varied for each layer.

[0030] (Thermoplastic resin composition 5) The thermoplastic resin composition 5 is a powdery composition with an average particle size of several tens of microns to one millimeter. Various materials, such as polyester, polyamide, polyolefin, ethylene-propylene-diene rubber, ethylene vinyl acetate, and silicone rubber, can be used as the thermoplastic resin composition 5. However, polyethylene is preferred in terms of the mechanical strength and water resistance of the wood substrate 10. The particle size of the thermoplastic resin composition 5 is not particularly limited, but a particle size similar to that of the wood material 4 is preferable for ease of mixing. If the particle size of the thermoplastic resin composition 5 is too small, it will slip through the wood material 4 and accumulate at the bottom, while if it is too large, it will accumulate on top of the wood material 4, resulting in an uneven wood substrate 10. Therefore, the particle size (average particle size) of the thermoplastic resin composition 5 is preferably in the range of 30 microns (μm) to 300 microns (μm).

[0031] The thermoplastic resin composition 5 may be used alone or in combination with several other types. From the viewpoint of the mechanical strength of the wood substrate 10, it is desirable for the thermoplastic resin composition 5 to contain 50 to 100 parts by mass of polyethylene per 100 parts by mass of the total thermoplastic resin composition 5. It is more desirable for the thermoplastic resin composition 5 to contain 80 to 100 parts by mass of polyethylene.

[0032] The polyethylene added to the thermoplastic resin composition 5 is not particularly limited, and can be appropriately selected from existing materials such as high-density polyethylene (polyethylene with a specific gravity of approximately 0.92 to 0.96), low-density polyethylene (polyethylene with a specific gravity of approximately 0.91 to 0.92), very low-density polyethylene (polyethylene with a specific gravity of less than 0.9), and linear low-density polyethylene (polyethylene with a specific gravity of less than 0.94), taking into consideration the reactivity during heating and pressure application and the fluidity of the raw material mixture 6. Of the above materials, it is more desirable to use high-density polyethylene in order to obtain a wood substrate 10 with high bending strength.

[0033] The polyethylene used in this embodiment may be biomass-derived polyethylene. Biomass-derived polyethylene is obtained by polymerizing a monomer containing biomass-derived ethylene. Since biomass-derived ethylene is used as the raw material monomer, the polymerized polyethylene is biomass-derived. Note that the raw material monomer for polyethylene may not contain 100% by mass of biomass-derived ethylene.

[0034] The material to be mixed into the thermoplastic resin composition 5 is not particularly limited, but examples thereof include acid-modified resins and organic peroxides.

[0035] (acid-modified resin) The acid-modified resin is used to improve the adhesion between the wood material 4 and the thermoplastic resin composition 5. When the main component of the thermoplastic resin composition 5 is polyethylene, the acid-modified resin is preferably an acid-modified polyolefin because of its ease of compatibility (high compatibility). In particular, maleic acid-modified polyethylene is preferably used as the acid-modified resin. Here, the "main component" refers to a component that accounts for 50% by mass or more of the total mass of the thermoplastic resin composition 5.

[0036] (Amount of acid-modified resin added) The amount of acid-modified resin added is preferably in the range of 3 to 40 parts by mass per 100 parts by mass of the total thermoplastic resin composition. If the amount of acid-modified resin added is less than 3 parts by mass, the effect of improving the adhesion between the wood material 4 and the thermoplastic resin composition 5 is insufficient, and sufficient strength cannot be imparted to the wood substrate 10. If the amount of acid-modified resin added exceeds 40 parts by mass, the effect of improving adhesion is limited, and only a slight improvement can be confirmed. The amount of the acid-modified resin added is more preferably within the range of 5 parts by mass to 20 parts by mass relative to 100 parts by mass of the entire thermoplastic resin composition.

[0037] (organic peroxide) The organic peroxide may be used to radically crosslink the raw material mixture 6 when the raw material mixture 6 is heated and pressurized. The organic peroxide is not particularly limited, and may be appropriately selected from existing materials such as peroxyketal, dialkyl peroxide, diacyl peroxide, and peroxyester in consideration of reactivity and stability.

[0038] The organic peroxide is a type of radical crosslinking agent, and examples thereof include hydroperoxides, diacyl peroxides, peroxydicarbonates, peroxyesters, peroxycarbonates, dialkyl peroxides, and ketone peroxides.

[0039] (additives) An additive such as wax may be mixed into the thermoplastic resin composition 5. Adding wax as an additive further improves the water resistance of the wood substrate 10. In addition, an additive such as wax also serves as a lubricant to uniformly mix the wood material 4 and the thermoplastic resin composition 5, or multiple types of thermoplastic resin compositions 5.

[0040] (Method of producing thermoplastic resin composition 5) The thermoplastic resin composition 5 can be prepared in powder form by a known method. When multiple types of materials are mixed into the thermoplastic resin composition 5, they are mixed by a known method. For example, if a polyethylene powder and an acid-modified polyolefin powder are mixed, a process such as freeze-pulverization is not required when pulverizing the thermoplastic resin composition 5, and a powder of the thermoplastic resin composition 5 can be easily obtained.

[0041] Furthermore, the thermoplastic resin composition 5 can be prepared by powdering resin pellets produced by a known method using a known method such as mechanical crushing or freeze crushing. When mixing a thermoplastic resin composition containing a mixture of resin pellets and powder, the resin pellets and powder may be mixed and then crushed, or the resin pellets may be crushed and then mixed with the powder.

[0042] The thermoplastic resin composition 5 can be prepared by, for example, heat-mixing multiple types of thermoplastic resin pellets using a single-screw kneader or a batch kneader, followed by mechanical pulverization or freeze-pulverization. For example, polyethylene pellets and acid-modified polyolefin pellets can be heat-mixed in a single-screw kneading extruder, pelletized, and freeze-pulverized to obtain a powder of the thermoplastic resin composition 5. That is, multiple types of thermoplastic resin compositions 5 can be kneaded by extrusion to obtain a powder of the thermoplastic resin composition 5. Furthermore, mixing multiple types of powdered thermoplastic resin compositions allows the thermoplastic resin compositions to be mixed more uniformly, resulting in a wood substrate 10 with excellent in-plane uniformity of bending strength.

[0043] (wood base material 10) The wood substrate 10 is formed by heating and pressurizing a raw material mixture 6 containing a wood material 4 in at least one of powder and chip form and a powdered thermoplastic resin composition 5, and is adjusted so that the normalized C—H area calculated from the absorption spectrum obtained by Fourier infrared spectroscopy is within the range of 0.07 to 1.00.

[0044] Here, we will explain Fourier infrared spectroscopy. First, infrared spectroscopy is a measurement method that obtains information about the chemical structure and state of a substance by measuring the infrared light absorbed by the substance, utilizing the principle that the amount of infrared light, which is light with a wavelength of 2.5 μm to 25 μm, absorbed by the substance changes based on the vibration and rotational motion of the substance's molecules. Specifically, the measurement method involves irradiating the substance with infrared light from a light source, generating an interference wave by combining the split transmitted light and reflected light, and calculating the light intensity of each wavenumber component from the signal intensity of the interference wave to measure the infrared spectrum. In particular, in this embodiment, the interference wave is calculated using the Fourier transform method, and measurement is performed by Fourier infrared spectroscopy, a method for measuring infrared spectra. A graph in which the wavenumber obtained by the above method is plotted on the horizontal axis and the measured absorbance (or transmittance) on the vertical axis is called an infrared absorption spectrum (or infrared transmission spectrum), and a unique pattern is observed for each substance. In this case, the absorbance on the vertical axis changes in peak intensity at a given wavenumber in proportion to the concentration and thickness of the substance, and in the case of crystalline substances, the amount of crystalline or amorphous parts, so quantitative analysis can also be performed from the height and area of ​​the peak.

[0045] As an example, Figure 3 shows the infrared absorption spectrum of a typical wood material 4. Wood material 4 has a peak due to OH groups derived from cellulose at wavenumbers of 3000 to 3500 cm. -1 The C-OH group peak appears around the wavenumber of 900 to 1200 cm -1 The peak area values ​​are S O-H、 S C-OH The baseline shown by the dashed line is used as the background for correction. In other words, the ranges enclosed by the solid and dashed lines in Figure 3 represent the peak area values ​​of the OH group and the C-OH group. In this embodiment, the peak area value was calculated by averaging values ​​obtained by measuring at 10 different measurement positions within the same sample.

[0046] 4 shows an example of the infrared absorption spectrum of the wood substrate 10 of this embodiment. In addition to the peaks derived from the wood material 4, peaks derived from the CH2 and CH3 groups derived from the thermoplastic resin composition 5 appear at wavenumbers of 2700 to 3000 cm. -1 The peak area is S C-H The baseline shown by the dashed line is used as the background for correction. In other words, the ranges enclosed by the solid and dashed lines in Figure 4 represent the peak area values ​​of the OH group, the C-OH group, the CH2 group, and the CH3 group.

[0047] From each peak area value, the composition ratio of the wood substrate 10 is adjusted using the following formula (1) so that the normalized CH area falls within the range of 0.07 to 1.00. Standardized CH area=S C-H / (S O―H +S C-OH )...Equation (1)

[0048] If the normalized C-H area is less than 0.07, the proportion of the wood material 4 is too high, making it difficult to impart the bending strength required for practical use. On the other hand, if the normalized C-H area exceeds 1.00, the proportion of the thermoplastic resin composition 5 is too high, making the wood substrate more likely to deform when heated and pressurized, which is undesirable. Furthermore, if the wood material 4 and the thermoplastic resin composition 5 are not mixed uniformly, the normalized C-H area may locally exceed 1.00. If the wood material 4 and the thermoplastic resin composition 5 are not mixed uniformly, the bending strength of the wood substrate 10 will vary, which is undesirable.

[0049] The normalized CH area is preferably in the range of 0.08 to 0.35. If the normalized CH area is within this range, it is possible to obtain a good wood substrate 10 that has higher bending strength and is less likely to deform.

[0050] (Method of manufacturing wood base material 10) Various known methods can be used for heating and pressurizing when manufacturing the wood substrate 10, but press molding using a frame mold as shown in FIG. 1 is suitable for manufacturing the wood substrate 10. The heating temperature is usually in the range of 120°C to 250°C, and must be above the melting point of the thermoplastic resin composition 5. However, if the heating temperature exceeds 250°C, significant thermal degradation of the wood material 4 may occur. The pressure applied is usually 10 kgf / cm. 2 More than 400kgf / cm 2 The value is within the following range and is appropriately set depending on the desired density of the wood substrate 10.

[0051] The density and shape of the wood substrate 10 obtained as described above are determined appropriately depending on the application. 3 More than 1.2g / cm 3 Within the following range, especially 0.6 g / cm 3 More than 1.1g / cm 3 The following ranges are preferred. A lower density of the wood substrate 10 makes it easier to handle when processing it into a decorative material, but a higher density of the wood substrate 10 allows for a harder wood substrate and decorative material. The wood substrate 10 can be made into a multi-layer structure with two or more layers, rather than a single layer, with different densities for each layer.

[0052] The method for producing the wood substrate 10 may use the release film 3 shown in Fig. 1. The material of the release film 3 may be any material that does not adhere to the thermoplastic resin composition 5, the metal plate 2, and the metal weight 8, and a fluorine film or the like is preferably used.

[0053] A metal plate 2 and a metal weight 8 that have been subjected to a non-stick treatment may be used instead of the release film 3. The non-stick treatment may be any treatment that makes the thermoplastic resin composition 5 less likely to adhere, and a fluorine coating or the like is preferably used.

[0054] [Second embodiment] The second embodiment will be described with reference to FIG. The second embodiment is a decorative material 12 in which a decorative layer 11 having a design property is laminated on the wood substrate 10 according to the first embodiment described above with reference to FIG. According to this embodiment, by laminating the design layer 11, which is a designable substrate, on the wood substrate 10, it is possible to impart designability.

[0055] That is, the wood base material 10 can be used as a decorative material by itself, but to give the wood base material 10 even more excellent design properties, a design layer 11 such as paper or film with a design such as a picture may be laminated onto the wood base material 10 to form a decorative material 12, as shown in Figure 5.

[0056] <Other effects> (1) The wood substrate 10 of this embodiment includes a wood material 4 in at least one of powder and chip form, and a thermoplastic resin composition 5, and has a normalized C—H area calculated from an absorption spectrum obtained by Fourier infrared spectroscopy using the following formula (1) in a range of 0.07 to 1.00. Standardized CH area=S C-H / (S O―H +S C-OH )...Equation (1)

[0057] Here, in equation (1), S C-H Wavenumber: 2700-3000cm -1 The area value of the peaks derived from the CH2 and CH3 groups in the vicinity, S O-H is a wave number of 3000-3500 cm -1 The area value of the peak derived from the OH group in the vicinity, S C-OH Wavenumber: 900-1200cm -1 The area values ​​of the peaks derived from the C-OH groups in the vicinity are shown.

[0058] With this configuration, the thermoplastic resin composition 5 is used as an adhesive instead of formaldehyde, which causes sick house syndrome, so it is possible to provide a wood substrate 10 that does not emit harmful substances. Furthermore, since the wooden substrate 10 contains the thermoplastic resin composition 5, the high water resistance of the thermoplastic resin composition 5 itself can impart excellent water resistance to the wooden substrate 10.

[0059] (2) The wood substrate 10 of this embodiment may have a normalized CH area calculated from an absorption spectrum obtained by Fourier infrared spectroscopy in the range of 0.08 to 0.35. With this configuration, it is possible to provide a favorable wood substrate 10 that has a higher bending strength and is less likely to deform.

[0060] (3) In the wooden substrate 10 of this embodiment, the mass ratio of the wooden material 4 to the thermoplastic resin composition 5 (wood material / thermoplastic resin composition) may be within a range of 95 / 5 to 70 / 30. With this configuration, it is possible to reliably provide a wood substrate 10 with high bending strength.

[0061] (4) In the wooden substrate 10 of this embodiment, the mass ratio of the wooden material 4 to the thermoplastic resin composition 5 (wood material / thermoplastic resin composition) may be within the range of 85 / 5 to 70 / 30. With this configuration, it is possible to reliably provide a wood substrate 10 with greater bending strength.

[0062] (5) The wood substrate 10 of this embodiment may contain a mushroom bed as a raw material in the wood material 4. With this configuration, it is possible to provide a wood substrate 10 that is beneficial in reducing the environmental impact.

[0063] (6) The wooden substrate 10 of this embodiment may contain polyethylene in the thermoplastic resin composition 5. This configuration can provide a wood substrate 10 with both good bending strength and water resistance. Furthermore, if biomass-derived polyethylene is included, a wood substrate 10 that is beneficial in reducing environmental impact can be provided.

[0064] (7) The thermoplastic resin composition 5 of the wood substrate 10 of this embodiment may contain an acid-modified polyolefin. With this configuration, it is possible to provide a wood substrate 10 with better bending strength.

[0065] (8) The wooden substrate 10 of this embodiment may contain an acid-modified polyolefin in the thermoplastic resin composition 5 in an amount of 3 to 40 parts by mass per 100 parts by mass of the entire thermoplastic resin composition. With this configuration, it is possible to reliably provide a wood substrate 10 with better bending strength.

[0066] (9) The decorative material 12 of this embodiment is obtained by laminating a decorative layer 11 having a design on the wooden substrate 10 of this embodiment. With this configuration, it is possible to provide a decorative material 12 that has better bending strength and water resistance than conventional decorative materials.

[0067] [Example] Below, examples 1 to 20 of wood base materials according to the first embodiment of the present invention and comparative example 1 will be explained. However, the present invention is not limited to the following examples 1 to 20.

[0068] Example 1 The thermoplastic resin composition of Example 1 was a single high-density polyethylene resin (HDPE) pellet. The resin pellet was mechanically pulverized to obtain a powdery thermoplastic resin composition having an average particle size of 100 μm, which was the base resin. The wood material used was a washed and dried mushroom bed (average particle size 2 mm) after harvesting. The wood material and the thermoplastic resin composition were dry mixed in a mass ratio (wood material / thermoplastic resin composition) of 85 / 15 to obtain a raw material mixture for the wood substrate.

[0069] This raw material mixture was placed in an aluminum mold and heated and pressed in a heat press to obtain the wood substrate of this example (pressing conditions: 40 kgf / cm 2 , 200℃ 10 min, substrate thickness: 10 mm, substrate density: 0.8 g / cm 3 ).

[0070] As described above, the wood substrate of this example is manufactured without using harmful substances such as formaldehyde that cause sick building syndrome, and therefore the wood substrate of this example can suppress the emission of harmful substances such as formaldehyde that cause sick building syndrome.

[0071] Example 2 In Example 2, the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) was changed from "85 / 15" in Example 1 to "90 / 10," and otherwise the wood substrate was obtained in the same manner as in Example 1.

[0072] Example 3 In Example 3, the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) was changed from "85 / 15" in Example 1 to "70 / 30," and otherwise the wood substrate was obtained in the same manner as in Example 1.

[0073] Example 4 The thermoplastic resin composition of Example 4 was a low-density polyethylene resin (LDPE) pellet alone, but the wood substrate was obtained in the same manner as in Example 1.

[0074] Example 5 The thermoplastic resin composition of Example 5 was a linear low-density polyethylene resin (LLDPE) pellet alone, but otherwise the wood substrate was obtained in the same manner as in Example 1.

[0075] Example 6 The components and masses of the thermoplastic resin composition of Example 6 are as follows. (1) High-density polyethylene resin 97 parts by mass (2) Acid-modified polyolefin: 3 parts by mass The above (1) and (2) were heated and kneaded in a batch kneader, and then mechanically pulverized to obtain a powdery thermoplastic resin composition. Except for this, a wood base material was obtained in the same manner as in Example 1.

[0076] Example 7 The components and masses of the thermoplastic resin composition of Example 7 are as follows. (1) High-density polyethylene resin 80 parts by mass (2) Acid-modified polyolefin 20 parts by mass The above (1) and (2) were heated and kneaded in a batch kneader, and then mechanically pulverized to obtain a powdery thermoplastic resin composition. Except for this, a wood base material was obtained in the same manner as in Example 1.

[0077] Example 8 The components and masses of the thermoplastic resin composition of Example 8 are as follows. (1) High-density polyethylene resin 60 parts by mass (2) Acid-modified polyolefin 40 parts by mass The above (1) and (2) were heated and kneaded in a batch kneader, and then mechanically pulverized to obtain a powdery thermoplastic resin composition. Except for this, a wood base material was obtained in the same manner as in Example 1.

[0078] Example 9 The components and masses of the thermoplastic resin composition of Example 9 are as follows. (1) High-density polyethylene resin 100 parts by mass (2) 1.5 parts by mass of organic peroxide (trade name: Perhexa C, manufactured by NOF Corporation) The above (1) and (2) were heated and kneaded in a batch kneader, and then mechanically pulverized to obtain a powdery thermoplastic resin composition. Except for this, a wood base material was obtained in the same manner as in Example 1.

[0079] Example 10 The components and masses of the thermoplastic resin composition of Example 10 are as follows. (1) High-density polyethylene resin 90 parts by mass (2) Acid-modified polyolefin 10 parts by mass (3) 1.5 parts by mass of organic peroxide (trade name: Perhexa C, manufactured by NOF Corporation) The above (1) to (3) were heated and kneaded in a batch kneader, and then mechanically pulverized to obtain a powdery thermoplastic resin composition. Except for this, a wood substrate was obtained in the same manner as in Example 1.

[0080] Example 11 The components and masses of the thermoplastic resin composition of Example 11 are as follows. (1) High-density polyethylene resin powder 90 parts by mass (2) Acid-modified polyolefin powder 10 parts by mass (3) 1.5 parts by mass of organic peroxide (trade name: Perhexa C, manufactured by NOF Corporation) A powdery thermoplastic resin composition was obtained by dry-mixing the above (1) to (3). Except for this, a wood substrate was obtained in the same manner as in Example 1.

[0081] Example 12 The thermoplastic resin composition of Example 12 was a polypropylene resin (PP) pellet alone. The resin pellets were mechanically crushed to obtain a powdery thermoplastic resin composition. A wood substrate was obtained in the same manner as in Example 1.

[0082] Example 13 The components and masses of the thermoplastic resin composition of Example 13 are as follows. (1) Polypropylene resin powder 90 parts by mass (2) Acid-modified polyolefin powder 10 parts by mass The polypropylene resin powder was obtained by mechanically crushing resin pellets in the same manner as in Example 12. The above (1) and (2) were dry-mixed to obtain a powdery thermoplastic resin composition. A wood substrate was obtained in the same manner as in Example 1 except for the above.

[0083] Example 14 In Example 14, the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) was changed from "85 / 15" in Example 1 to "65 / 35," and otherwise the wood substrate was obtained in the same manner as in Example 1.

[0084] Example 15 In Example 15, the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) was changed from "85 / 15" in Example 1 to "96 / 4," and otherwise the wood substrate was obtained in the same manner as in Example 1.

[0085] Example 16 The thermoplastic resin composition of Example 16 was a single polypropylene resin (PP) pellet. The resin pellets were mechanically crushed to obtain a powdered thermoplastic resin composition. The wood material of Example 16 was made by washing and drying wood chips (average particle size 2 mm). Other than that, the wood substrate was obtained in the same manner as in Example 15.

[0086] Example 17 The wood base material of Example 17 was obtained in the same manner as in Example 12, except that washed and dried wood chips (average particle size 2 mm) were used.

[0087] Example 18 The thermoplastic resin composition of Example 18 was a polypropylene resin (PP) pellet alone. The resin pellets were mechanically crushed to obtain a powdery thermoplastic resin composition. A wood substrate was obtained in the same manner as in Example 15.

[0088] Example 19 The wood base material of Example 19 was obtained in the same manner as in Example 15, except that washed and dried wood chips (average particle size 2 mm) were used.

[0089] Example 20 The components and masses of the thermoplastic resin composition of Example 20 are as follows. (1) Polypropylene resin powder 80 parts by mass (2) Acid-modified polyolefin powder 20 parts by mass The polypropylene resin powder was obtained by mechanically pulverizing resin pellets in the same manner as in Example 12. The above (1) and (2) were dry-mixed to obtain a powdery thermoplastic resin composition. Furthermore, wood chips (average particle size 2 mm) that had been washed and dried were used as the wood material for Example 20. A wood substrate was obtained in the same manner as in Example 15, except for the above.

[0090] (Comparative Example 1) In Comparative Example 1, a wood substrate was obtained in the same manner as in the case of particle board. Specifically, the wood material and adhesive were mixed using a drum blender, and the mixture was allowed to fall naturally and dispersed without applying external forces such as pressure or suction. Urea resin adhesive was used as the adhesive, and the wood material and adhesive were mixed at a mass ratio (wood material / adhesive) of 85 / 15. The mixture was then compacted to obtain the wood substrate of this comparative example.

[0091] (Evaluation of wood substrates) For the above Examples 1 to 20 and Comparative Example 1, Fourier infrared spectroscopy (normalized CH area measurement), mechanical strength, water resistance, and substrate deformation were evaluated.

[0092] (Fourier infrared spectroscopy: normalized CH area measurement) Fourier-type infrared spectroscopy was performed using a PerkinElmer Fourier-type infrared spectrometer (Spectrum Spotlight 400) at 4000 cm -1 From 400cm -1 The absorption spectrum was obtained. The normalized CH area was calculated from the obtained absorption spectrum using the following formula (1). Standardized CH area=S C-H / (S O―H +S C-OH )...Equation (1)

[0093] Here, in equation (1), S C-H Wavenumber: 2700-3000cm -1 The area value of the peaks derived from the CH2 and CH3 groups in the vicinity, S O-H is a wave number of 3000-3500 cm -1 The area value of the peak derived from the OH group in the vicinity, S C-OH Wavenumber: 900-1200cm -1The area values ​​of the peaks derived from the C-OH groups in the vicinity are shown. In Fourier infrared spectroscopy, a sample is considered to pass if the normalized CH area is within the range of 0.07 to 1.00.

[0094] (mechanical strength) The mechanical strength was measured by bending strength according to the method of JISA5908. The measured value (unit: N / mm 2 The evaluation criteria for mechanical strength for the above-mentioned materials are as follows, based on the JIS standard values. The mechanical strength was evaluated according to the following three-level criteria: "good", "△", and "×", with "good" and "△" being acceptable and "×" being unacceptable. 〇:13 or more (pass) △: 8 or more but less than 13 (pass) ×: Less than 8 (fail)

[0095] (water resistance) Water resistance was measured by measuring the water absorption thickness swelling rate in accordance with JISA 5908. The evaluation criteria for water resistance for the measured value (unit: %) were set as follows, based on the standard values ​​of the JIS. The evaluation criteria for water resistance were as follows: 3 levels of "good", "△", and "×", with "good" and "△" being acceptable and "×" being unacceptable. 〇: Less than 8 (pass) △: 8 or more but less than 12 (pass) ×: 12 or more (fail)

[0096] (Substrate deformation) Substrate deformation is a state in which the substrate surface is partially swollen, and is mainly caused by the accumulation of gas generated inside the substrate during pressing. Since substrate deformation is clearly reflected by the condition of the substrate edge, the appearance of the substrate edge was visually evaluated. The evaluation criteria for substrate deformation were as follows: 3 levels of "good", "△", and "×", with "good" and "△" being pass and "×" being fail. 〇: No voids (pass) △: Traces of voids (pass) ×: Voids present (failed)

[0097] (Evaluation results) The evaluation results for the wood substrates are as shown in Table 1 below. In the examples in the table, the "raw material blend ratio" indicates the mass ratio (wood material / thermoplastic resin composition), and in the comparative examples in the table, the "raw material blend ratio" indicates the mass ratio (wood material / adhesive).

[0098] [Table 1]

[0099] (Evaluation results of Fourier infrared spectroscopy) Only Comparative Example 1 failed the evaluation of Fourier infrared spectroscopy. As in Examples 1 to 20, wood substrates containing polyolefin in the thermoplastic resin composition exhibited a peak intensity of 2700 to 3000 cm -1 The normalized CH area is large because it has a characteristic peak around 2700-3000 cm. The normalized CH area calculated for wood material alone is 0.05. -1 The peak caused by the adhesive of Comparative Example 1 is hardly detected in the vicinity.

[0100] Comparing Examples 1 to 20, Example 14, which contains the largest amount of thermoplastic resin composition, has the largest normalized C—H area, and Examples 15, 16, and 18 to 20, which contain the smallest amount of thermoplastic resin composition, have the smallest normalized C—H area.

[0101] (Mechanical strength evaluation results) The mechanical strength was acceptable for all of Examples 1 to 20 and Comparative Example 1. Of these, 12 examples, 2, 4, 5, 8, 12, 13, and 15 to 20, had evaluation results that included "Fair." In Examples 2, 15, 16, and 18 to 20, the proportion of wood material was high, which is thought to have reduced the mechanical strength. In Examples 4 and 5, LDPE and LLDPE were used as the base resin, respectively, which is thought to have reduced the mechanical strength compared to HDPE. In Example 8, 40 parts of acid-modified polyolefin was blended, which is thought to have reduced the mechanical strength. In Examples 12 to 13 and 17, PP was used as the base resin, which is thought to have reduced the mechanical strength compared to HDPE.

[0102] (Water resistance evaluation results) The only example that failed the water resistance test was Comparative Example 1. The conventional method using an adhesive is inferior in water resistance to Examples 1 to 20 of the present invention. Comparing Examples 1 to 20, 13 examples, including Examples 1 to 5, 11 to 12, and 15 to 20, are marked with "△". Examples 1 to 5, 12, and 15 to 19 are material formulations that do not contain either acid-modified polyolefin or organic peroxide, and are thought to have insufficient (slightly inferior) water resistance. Examples 11 and 20 are material formulations that contain both acid-modified polyolefin and organic peroxide, but when mixing the thermoplastic resin composition, it is not heated and kneaded, but is mixed in powder form. Powder mixing does not result in complete uniform mixing, and is thought to have resulted in insufficient (slightly inferior) water resistance. Example 14 is a material formulation that does not contain either acid-modified polyolefin or organic peroxide, but because the proportion of the thermoplastic resin composition is high, water resistance was good.

[0103] (Evaluation results of substrate deformation) In terms of substrate deformation, all of Examples 1 to 20 and Comparative Example 1 passed the test. Of these, only two, Examples 3 and 14, received an evaluation result that included "Fair." It is believed that the substrate deformation was more likely to occur in Example 3 because Example 3 contained 30 parts of the thermoplastic resin composition and in Example 14 contained 35 parts.

[0104] (Overall evaluation results) As a comprehensive evaluation result, Examples 1 to 20 were "passed" in all evaluation items, and as is clear from Table 1, it was shown that the wood substrate of the present invention has excellent mechanical strength and water resistance, and there is no problem with substrate deformation. Furthermore, since the wood substrate of the present invention does not contain harmful substances that cause sick building syndrome, it can suppress the emission of harmful substances that cause sick building syndrome, such as formaldehyde. [Explanation of symbols]

[0105] 1... Jig for making wood substrate, 2... Metal plate (bottom), 3... Release film, 4... Wood material, 5... Thermoplastic resin composition, 6... Raw material mixture, 7... Metal plate for adjusting thickness, 8... Metal weight, 9... Press top plate, 10... Wood substrate, 11... Design layer, 12... Decorative material

Claims

1. A wood substrate comprising a wood material in at least one of powder and chip form and a thermoplastic resin composition, a normalized C-H area calculated from an absorption spectrum obtained by Fourier infrared spectrometry using the following formula (1) is in the range of 0.07 or more and 1.00 or less, The thermoplastic resin composition contains an acid-modified polyolefin, the content of the acid-modified polyolefin is in the range of 20 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the total thermoplastic resin composition, The average particle size of the wood material is in the range of 1 mm to 5 mm, A wood substrate characterized in that the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) is within the range of 95 / 5 to 70 / 30 (excluding 80 / 20). Normalized C-H area = S Ｃ－Ｈ / (S Ｏ―Ｈ +S Ｃ－ＯＨ ) ・・・Formula (1) (Here, in formula (1), S Ｃ－Ｈ Wave number is 2700-3000 cm －１ Nearby CH ２ Group, CH ３ The area value of the peak derived from the group, S Ｏ－Ｈ Wave number is 3000-3500 cm －１ The area value of the peak derived from the OH group in the vicinity, S Ｃ－ＯＨ Wave number is 900 to 1200 cm －１ The area of ​​the peak derived from the C—OH group in the vicinity is shown.)

2. A wood substrate comprising a wood material in at least one of powder and chip form and a thermoplastic resin composition, a normalized C-H area calculated from an absorption spectrum obtained by Fourier infrared spectrometry using the following formula (1) is in the range of 0.07 or more and 1.00 or less, The thermoplastic resin composition contains an acid-modified polyolefin, the content of the acid-modified polyolefin is within the range of 20 parts by mass or more and 40 parts by mass or less (excluding 25 parts by mass) relative to 100 parts by mass of the entire thermoplastic resin composition; A wood substrate characterized in that the average particle size of the wood material is in the range of 1 mm to 5 mm. Normalized C-H area = S Ｃ－Ｈ / (S Ｏ―Ｈ +S Ｃ－ＯＨ ) ・・・Formula (1) (Here, in formula (1), S Ｃ－Ｈ Wave number is 2700-3000 cm －１ Nearby CH ２ Group, CH ３ The area value of the peak derived from the group, S Ｏ－Ｈ Wave number is 3000-3500 cm －１ The area value of the peak derived from the OH group in the vicinity, S Ｃ－ＯＨ Wave number is 900 to 1200 cm －１ The area of ​​the peak derived from the C—OH group in the vicinity is shown.)

3. 2. The wood substrate according to claim 1, wherein the normalized C-H area is in the range of 0.08 to 0.

35.

4. The wood substrate according to claim 2, characterized in that the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) is within the range of 95 / 5 to 70 / 30.

5. The wood substrate according to claim 2, characterized in that the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) is within the range of 85 / 15 to 70 / 30.

6. 6. The wood substrate according to claim 1, wherein the wood material contains a mushroom bed as a raw material.

7. 7. The wood substrate according to claim 1, wherein the thermoplastic resin composition contains polyethylene.

8. 8. The wood substrate according to claim 1, wherein the wood substrate does not contain a thermosetting resin.

9. 8. The wood substrate according to claim 1, wherein the wood substrate does not contain a thermosetting resin such as a phenol resin, a urea resin, a melamine resin, or a urea-melamine resin.

10. A decorative material comprising the wood substrate according to any one of claims 1 to 9 and a decorative substrate laminated thereon.

11. The method includes a step of heating and pressurizing a raw material mixture containing a wood material in at least one of powder and chip form and a powdered thermoplastic resin composition to form a wood substrate, The wood base material has a normalized C-H area calculated from an absorption spectrum obtained by Fourier infrared spectroscopy using the following formula (1) in the range of 0.07 to 1.00, The thermoplastic resin composition contains an acid-modified polyolefin, the content of the acid-modified polyolefin is in the range of 20 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the total thermoplastic resin composition, The average particle size of the wood material is in the range of 1 mm to 5 mm, A method for producing a wood substrate, wherein the mass ratio of the wood material to the thermoplastic resin composition (wood material / thermoplastic resin composition) is within the range of 95 / 5 to 70 / 30 (excluding 80 / 20). Normalized C-H area = S Ｃ－Ｈ / (S Ｏ―Ｈ +S Ｃ－ＯＨ ) ・・・Formula (1) (Here, in formula (1), S Ｃ－Ｈ Wave number is 2700-3000 cm －１ Nearby CH ２ Group, CH ３ The area value of the peak derived from the group, S Ｏ－Ｈ Wave number is 3000-3500 cm －１ The area value of the peak derived from the OH group in the vicinity, S Ｃ－ＯＨ Wave number is 900 to 1200 cm －１ The area of ​​the peak derived from the C—OH group in the vicinity is shown.)

12. The method includes a step of heating and pressurizing a raw material mixture containing a wood material in at least one of powder and chip form and a powdered thermoplastic resin composition to form a wood substrate, The wood base material has a normalized C-H area calculated from an absorption spectrum obtained by Fourier infrared spectroscopy using the following formula (1) in the range of 0.07 to 1.00, The thermoplastic resin composition contains an acid-modified polyolefin, the content of the acid-modified polyolefin is within the range of 20 parts by mass or more and 40 parts by mass or less (excluding 25 parts by mass) relative to 100 parts by mass of the entire thermoplastic resin composition; A method for producing a wood substrate, wherein the average particle size of the wood material is in the range of 1 mm to 5 mm. Normalized C-H area = S Ｃ－Ｈ / (S Ｏ―Ｈ +S Ｃ－ＯＨ ) ・・・Formula (1) (Here, in formula (1), S Ｃ－Ｈ Wave number is 2700-3000 cm －１ Nearby CH ２ Group, CH ３ The area value of the peak derived from the group, S Ｏ－Ｈ Wave number is 3000-3500 cm －１ The area value of the peak derived from the OH group in the vicinity, S Ｃ－ＯＨ Wave number is 900 to 1200 cm －１ The area of ​​the peak derived from the C—OH group in the vicinity is shown.)

13. The step of producing the powdery thermoplastic resin composition includes: A step of kneading a plurality of types of thermoplastic resin compositions by an extrusion method; a step of pulverizing the kneaded thermoplastic resin composition into a powder; The method for producing a wood substrate according to claim 11 or 12, comprising:

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