JP2023118669A - Wooden chip lamina board and manufacturing method thereof - Google Patents

Abstract

To provide a wooden board which has superior surface smoothness than conventional OSB and which can be suitably used as a substrate serving as a decorative board by adhering a decorative material directly on itself.SOLUTION: A wood chip lamina board 1 has an average value of 40 μm or less of a maximum height showing surface roughness defined by Japanese Industrial Standards JIS B 0601:2013 and a maximum value of 50 μm or less. A first wood chip lamina group consisting of an aggregation of wood chip laminas 2 having a thickness of 0.6 mm or less and a second wood chip lamina group consisting of the aggregation of wood chip laminas 3 having the thickness of greater than 0.6 mm or more are prepared, 68 wt% or more, preferably 70 wt% or more, of the first wood chip lamina group to a total amount of the first and second wood chip lamina groups is mixed to obtain a raw material wood chip lamina, adhesive agent is applied, mixed, aggregated on the raw material wood chip lamina, integrated by hot pressing and manufactured. The wood chip lamina board can be suitably used as a substrate serving as a decorative board 5 by adhering a decorative material 4 such as a veneer or decorative sheet directly on itself.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a wood slice board and a manufacturing method thereof.

Oriented strand boards (OSB) are known as wooden boards obtained by mixing small pieces or thin pieces of wood with an adhesive, accumulating them, and integrating them under heat and pressure. OSB is a type of structural panel stipulated by JAS, and is standardized as a type of particle board by JIS. Consideration is also being given to using it as a base material for plates.

Japanese Patent Publication No. 2007-521163

Conventional OSB is generally made by laminating a large number of wood slices with a thickness of 0.7 to 1.2 mm in a mutually overlapping state with a thermosetting resin adhesive interposed therebetween, and then pressing this laminate at a high temperature to form a plate. However, due to the uneven distribution of the adhesive and the unevenness of the press load, it often appears on the surface in a state where some of the wood flakes are curled up, resulting in poor surface smoothness. Therefore, it has been practically difficult to directly attach a decorative material such as a veneer or a decorative sheet to the surface of the OSB. Therefore, when OSB is used as a substrate for a decorative board, a surface material having excellent surface smoothness such as MDF is adhered to the surface of the OSB, and then a decorative material such as a veneer or a decorative sheet is adhered to form a decorative board. However, the use of OSB alone as a base material for decorative boards has not hitherto been carried out.

Therefore, the problem to be solved by the present invention is to provide a wood board with improved surface smoothness, and a base material for making a decorative board by directly adhering a decorative material such as a veneer or a decorative sheet thereon. is to make it available as

In order to solve this problem, the invention according to claim 1 of the present application is a wood slice board obtained by mixing and accumulating wood slices and an adhesive and integrating them by heat and pressure, The average maximum height indicating surface roughness defined in B 0601:2013 is 40 μm or less and the maximum value is 50 μm or less.

The invention according to claim 2 of the present application provides a first group consisting of an aggregate of wooden slices having a thickness of 0.6 mm or less, and a first group consisting of an aggregate of wooden slices having a thickness of more than 0.6 mm. A second group of wooden slices is prepared, and the first group of wooden slices is used in an amount of 68% by weight or more with respect to the total compounding amount of the first group of wooden slices and the second group of wooden slices. This is a method of manufacturing a wooden board, characterized in that a raw material wooden board is prepared, an adhesive is applied to and mixed with the raw material wooden board, the raw material wooden board is accumulated, and the raw material wooden board is integrated by heat and pressure.

The invention according to claim 3 of the present application is characterized in that, in the method for manufacturing a wooden slice board according to claim 2, the first group of wooden slices contains shavings generated when the wooden slices are obtained. do.

The invention according to claim 4 of the present application is a wooden plank manufactured by the manufacturing method according to claim 2 or 3.

According to the present invention, surface smoothness is significantly improved over conventional OSB, and it has surface smoothness comparable to or equivalent to MDF, which is known to have good surface smoothness, and various physical properties An excellent wood-cutting plate is provided. Therefore, as a base material for directly adhering a decorative material such as a board or a decorative sheet on the board to form a decorative board, the wooden thin board according to the present invention can be suitably used in place of conventionally used MDF or the like. can be used.

1 is a side view schematically showing a wood flake plate according to the present invention; FIG. 1 is a side view schematically showing a decorative board using the wooden flake board according to the present invention as a base material; FIG. It is a figure which shows the measuring point of the surface roughness test in a test example.

TECHNICAL FIELD The present invention relates to a wood flake board obtained by mixing wood flakes and an adhesive, accumulating them, and integrating them under heat and pressure. FIG. 1 is a cross-sectional view showing this wood slice plate 1 alone, where reference numeral 2 indicates wood slices with a thickness of 0.6 mm or less, and reference numeral 3 indicates wood slices with a thickness of more than 0.6 mm. FIG. 2 is a cross-sectional view of a decorative board 5 obtained by using this wooden board 1 as a base material and applying a decorative material 4 thereon.

Wood slices are prepared by thinly cutting hardwood or coniferous raw wood with a flaker. Wood slices may be obtained from broadleaf trees and conifers that can be reforested.

The moisture content of the wood flakes is preferably 15% by weight or less, and the wood flakes are dried until the water content falls below this moisture content before entering the manufacturing process of the wood flakes. If the water content exceeds 15% by weight, an extremely high-density layer tends to form on the surface of the wooden board, requiring a long time for pressing during pressure molding. The moisture content of the wood shavings can be obtained from the formula (m ₁ -m ₀ )×100/m ₀ in accordance with Japanese Industrial Standard JIS A 5905-2003 6.4. Here, m ₁ is the mass (g) of the wood slice sample before drying, and m ₀ is the mass (g) when the wood slice sample is placed in an air dryer at 103 ° C. and has a constant weight. be.

The wood flake used for the wood flake board preferably has a length of 10 to 200 mm and a width of 1 to 5 mm. If the length of the wood slice exceeds 200 mm, it curls when dried, and if it is heat-pressed in the curled state, it causes local cavities and poor adhesion, resulting in punctures and poor strength. cause.

As mentioned above, the conventional OSB uses wood flakes with a thickness of 0.7 to 1.2 mm. A first wooden slice group and a second wooden slice group consisting of an aggregate of wooden slices having a thickness of more than 0.6 mm are prepared, and the first wooden slice group and the second wooden slice group are prepared. 68% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more of the first group of wood flakes is mixed with the adhesive. That is, where A is the weight of the first group of wooden slices and B is the weight of the second group of wooden slices, A/(A+B)≧68%, preferably ≧70%, more preferably ≧80%. Mix and use. This point will be described in detail later with reference to test examples, but the reason for classifying the first group of wooden slices and the second group of wooden slices with the thickness of 0.6 mm as the branching point is as follows. be.

That is, as described above, conventional OSB is expected to be used mainly as a structural panel, and it is also expected to be used as a base material for making a decorative board by attaching a decorative material such as a veneer or a decorative sheet to the surface. Therefore, wooden slices with a thickness of 0.6 mm or more, mainly 0.7 to 1.2 mm, which can be manufactured at a relatively low cost and with high productivity, were used as raw materials for OSB. On the other hand, in order to improve the surface smoothness for use as a base material for decorative boards, it is naturally expected that the thickness of the wood flakes used as raw materials should be reduced. The thinner the thickness, the more bulky it becomes, making it difficult to manage and increasing the cost, so it was not generally manufactured. Also, if an attempt is made to manufacture an OSB using only thin wood slices with a thickness of 0.6 mm or less, the mat will not be stable in the production line, and will tilt, crumble, or topple over, causing the line to stop. there were. Therefore, in the present invention, while using wood flakes having a thickness of more than 0.6 mm (thickness of 0.7 to 1.2 mm) that have been generally manufactured in the past, thinner wood flakes are used to a certain extent. The present inventors have noted that by blending or mixing, it is possible to efficiently produce a wood-cut thin board having surface smoothness that can be suitably used as a base material for a decorative board at a relatively low cost.

Furthermore, the wood flakes having a thickness of 0.6 mm or less, which constitute the first wood flake group, are assumed to have an average thickness of about 0.35 mm, and are compressed to 1/2 the thickness by hot pressing. , or if the wood flakes bite into each other by 1/2 thickness, the average depth of unevenness on the surface of the obtained wood flake board is assumed to be about 0.175 mm. When using this wood flake board as a base material for a decorative board, the decorative material such as a veneer or a decorative sheet attached to its surface generally has a thickness of 0.2 mm or more. Even if the surface has an unevenness of about 0.175 mm, it can be absorbed by attaching a decorative material having a thickness exceeding the depth of the unevenness, and the unevenness is less likely to appear on the decorative surface. On the other hand, when the upper limit of the thickness of the wood flakes constituting the first wood flake group is larger (for example, 0.7 mm), the unevenness appearing on the surface of the obtained wood flake board becomes a decorative material. The thickness is approximately the same as or greater than the thickness of the decorative board, and even if the decorative material is attached, the unevenness of the surface cannot be absorbed and the unevenness appears on the decorative surface, which greatly impairs the commercial value of the decorative board. . For this reason, when classifying the first wooden slice group and the second wooden slice group, the thickness of 0.6 mm is used as the standard, and the wooden slices with a thickness of 0.6 mm or less are classified as the first wooden slice group, Wood flakes with a thickness of more than 0.6 mm were taken as the second wood flake group.

Thermosetting resins such as urea resins, melamine urea resins, phenol resins, polyurethane resins, and epoxy resins can be used alone or in appropriate mixtures as adhesives to be applied to the wood slices. A polyurethane resin or a melamine urea resin is used from the viewpoint of shortening the press time during molding and improving the water resistance of the molded product. As the polyurethane resin, an isocyanate compound having two or more isocyanate groups in the molecule, such as crude diphenylmethane-4,4'-diisocyanate ("Sumidule 44V20" manufactured by Sumika Covestro Urethane Co., Ltd.) can be used.

The amount of the adhesive to be used is preferably 4 to 30 parts by weight in solid content with respect to 100 parts by weight of the absolute dry weight of the wood slice. If the amount of adhesive solids is less than 4 parts by weight per 100 parts by weight of the absolute dry weight of the wood flakes, the bending strength of the wood flakes will decrease and the board will not be suitable as a base material for decorative boards. If it exceeds, the amount becomes excessive and the rigidity becomes more than necessary, which is economically disadvantageous. More specifically, when an isocyanate compound is used as the adhesive, the solid content is preferably 4 to 12 parts by weight, and when a melamine urea resin is used, the solid content is preferably 15 to 25 parts by weight.

Next, a method for manufacturing a wooden plank according to the present invention will be described. As described above, the first wooden slice group consisting of an aggregate of wooden slices with a thickness of 0.6 mm or less, and the second wooden slice group consisting of an aggregate of wooden slices with a thickness of more than 0.6 mm. 70% by weight or more, more preferably 80% by weight or more of the first group of wooden flakes, based on the total amount of the first group of wooden flakes and the second group of wooden flakes. After preparing the raw material wood flakes by mixing so as to obtain the above-mentioned adhesive, the above-mentioned adhesive is applied to the surface and mixed. A spray method can be used as the coating method. For example, the raw wood flakes are put into a rotating drum that rotates at a low speed, and the adhesive is sprayed when the raw wood flakes naturally fall from the rotating drum. method can be adopted.

Next, the raw wood slice coated with the adhesive is shaped into a mat, and hot-pressed with a press. The thermosetting adhesive is hardened by the heat during thermocompression molding, and the raw wood slices are strongly bonded to each other to produce a wood slice board. The hot pressing temperature is generally 150-230° C., depending on the type of adhesive used.

As demonstrated by the following test examples, the wood shavings produced in this way have significantly improved surface smoothness compared to OSB according to the prior art, and the density distribution is 0.3 to 0.3. 0.95 g/cm ³ , a bending strength of 25 to 100 MPa, and a peel strength of 0.3 to 3.0 MPa. It can be suitably used as a base material for Regarding the density distribution of the wood flakes, the formation of a high-density layer on the surface of the wood flakes can be effectively prevented by using raw wood flakes with a moisture content of 15% by weight or less. In addition, the density distribution can be set within the range of 0.3 to 0.95 g/m ³ by adjusting the timing and pressure of bringing the hot plate into contact with the wood slice mat during hot pressing. , wood flakes with a uniform density distribution are produced.

EXAMPLES Examples and comparative examples of the present invention will be described below with reference to test examples. In this test example, sample A (mainly wood slices with a thickness of 0.1 to 0.6 mm), which is cut from a Japanese cypress log with a flaker and has a thickness of 0.6 mm or less, is obtained. A sample B having a thickness of 0.7 to 1.2 mm was obtained. The length and width of the wooden slices used as samples A and B were the same, and the length was 10 to 200 mm and the width was 1 to 50 mm. Then, these samples A and B were mixed at weight ratios of 80%, 70%, 68%, 66%, 64%, 62%, 60%, 50% and 30% of the total weight (A+B). The raw wood shavings were prepared by changing them in 9 ways, and the adhesive consisting of crude diphenylmethane-4,4'-diisocyanate was applied by the above-mentioned spray method to make a mat. ² for 9 minutes to obtain specimens 1 to 9 of 300 mm×300 mm×thickness 12 mm.

For comparison, MDF, which is known to have excellent surface smoothness, and OSB according to the prior art (only sample B was used as a raw wood slice) were used as Comparative Examples A to D. Comparative Examples A and B are MDF that is actually marketed as a floor substrate, and Comparative Examples C and D are OSB that is actually marketed as a structural panel. The dimensions of Comparative Examples A to D were also 300 mm×300 mm×12 mm in thickness, similar to the specimen.

For each of these test specimens 1 to 9 and Comparative Examples A to D (hereinafter collectively referred to as "test specimens"), the surface shape was measured by a surface roughness measuring instrument (JIS B 0651: 2001, surf test SJ-310, manufactured by Mitutoyo Corporation). As shown in FIG. 3, the test piece with a plane size of 300 mm×300 mm was divided into 9 areas of 100 mm×100 mm, and the center of each area was set as points 1 to 9. Specifically, a measuring instrument was placed on the surface of each test piece, and the stylus set at each measuring point moved in a linear range of 15 mm in length, and the uneven shape was automatically formed at a pitch of 0.01 mm. by measuring. Measurement of the uneven shape is performed by calculating the maximum height (JIS B 0601: 2013, the distance from the bottom of the deepest recess to the top of the highest protrusion Rz = Rv + Rq) within this measurement range, and then measuring at each measuring point. Table 1 shows the average and maximum measured maximum heights.

Table 2 shows the results of visual evaluation of the surface state when a decorative sheet was directly adhered to each of these test samples 1 to 9 and comparative examples A to D. In this table, ○ indicates that the surface of the decorative sheet has no unevenness on the surface of the substrate and a good surface condition is observed, and X indicates that the surface of the decorative sheet has unevenness on the surface of the substrate and is defective. It shows that the surface state was observed.

As can be seen from the results shown in Table 1, as the weight blending ratio of sample A increases, the average value and maximum value of the maximum height Rz of the surface unevenness tend to decrease. All of the bodies 1 to 9 are the largest compared to the conventional OSB (Comparative Examples C and D: both have extremely large average and maximum values of the maximum height Rz, indicating that the surface has large unevenness) The average value and maximum value of the height Rz are small, and although the surface smoothness is improved, the weight blending ratio of the sample A is 66% or less. , B). On the other hand, in the test specimens 1 to 3 in which the weight blending ratio of sample A was 68% or more, surface smoothness close to that of MDF (specimens A and B) was obtained, and in particular, the weight blending ratio of sample A was It was confirmed that 70% or more (specimens 1 and 2) had surface smoothness substantially equal to that of MDF (comparative examples A and B).

Moreover, as can be seen from the results shown in Table 2, all of these test specimens 1 to 3 had good surface conditions when the decorative sheet was directly adhered thereon. From these results, the wood-cut flake board manufactured with the weight blending ratio of sample A being 68% or more, more preferably 70% or more, is suitable for use as a base material for decorative board in place of MDF. It has been proven.

In the above test examples, the maximum weight blending ratio of sample A was 80% (test sample 1), but from the results shown in Table 1, if more sample A was blended, the maximum surface height Rz The average and maximum values of are smaller, and surface smoothness equal to or greater than that of MDF (specimens A and B) is obtained. be. However, the production of wood flakes with a thickness of 0.1 to 0.6 mm is inferior to the production of wood flakes with a thickness of 0.7 mm or more, and the cost increases. Excessive blending is impractical. In addition, by mixing a certain amount or more of the sample B, which is made of relatively thick wood flakes, the weight of the sample B plays a role of sinking the mat as a whole, so that the mat is stable in the production line and does not tilt. , it is possible to prevent the line from stopping due to collapsing or falling. From these points of view, it is preferable that the weight blending ratio of Sample A is 95% or less.

In addition, in the above test examples, as described above, not only wood flakes with a thickness of 0.1 to 0.6 mm, but also wood powder and debris that inevitably occur when obtaining these thin wood flakes A sample A is prepared by mixing shaving powder with a thickness of less than 0.1 mm. The shaving powder contained in sample A can be obtained without the need for separation work from wood shavings with a thickness of 0.1 to 0.6 mm after obtaining sample A, so workability and cost merits Not only is it improved, but raw material loss can be reduced. Furthermore, when the shaving powder is mixed in the raw wood shavings, the shaving powder enters the gaps between the wood shavings during hot pressing and fills the gaps. It contributes to improving various physical properties as well as improving the properties.

Although the present invention has been described in detail above with reference to test examples, the present invention can be modified or changed in various ways within the scope of the invention defined by the description of the claims.

1 Wood thin plate (base material)
2 Wood slices with a thickness of 0.6 mm or less 3 Wood slices with a thickness of more than 0.6 mm 4 Decorative material 5 Decorative board

Claims (4)

A wood thin plate obtained by mixing and accumulating wood thin pieces and an adhesive and integrating them by heat and pressure, and having a maximum height exhibiting surface roughness defined by Japanese Industrial Standard JIS B 0601:2013. A wooden plank having an average value of 40 μm or less and a maximum value of 50 μm or less. A first wooden slice group consisting of an aggregate of wooden slices with a thickness of 0.6 mm or less and a second wooden slice group consisting of an aggregate of wooden slices with a thickness of more than 0.6 mm are prepared. , the first wood flake group is blended in an amount of 68% by weight or more with respect to the total amount of the first wood flake group and the second wood flake group to form a raw wood flake, and the raw wood flake is adhered to the raw wood flake. A method for producing a wooden plank, characterized by applying and mixing agents, accumulating them, and integrating them under heat and pressure. 3. The method of manufacturing a wooden plank according to claim 2, wherein said first group of wooden planks contains shavings generated when the wood planks are obtained. A wooden plank manufactured by the manufacturing method according to claim 2 or 3.