JPH06316036A - Production of composite board - Google Patents

Abstract

PURPOSE:To produce a composite board wherein such a fault is solved as the composite board is warped in an arm-shape by setting the water content of an MDF (medium duty fiber board) lower than the water content of a conifer plywood and utilizing shrinkage difference attended with the change in the water content thereof in the case of heating and pressurizing the MDF and the conifer plywood. CONSTITUTION:A composite board applied to building materials is produced by laminating both a conifer plywood constituted of many sheets of conifer veneers 3-5 and an MDF (medium duty fiber board) 1 through an adhesive and thereafter heating and pressurizing them. In the case, the water content of the MDF 1 is set lower than the water content of the conifer plywood and shrinkage difference attended with the change in the water content thereof is utilized. By the way, the water content of the MDF 1 is set to <=3% and the water content of the conifer plywood is set to an air-dried state. Thereby the composite board has the sufficient characteristics as the substitute material of lauan plywood and also such a fault is solved as the composite board is warped in an arm-shape. Therefore the manufacturing method for the composite board deals with reckless deforestation of raw lumber of lauan and the global environment is protected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite board used as a building material or a furniture material and a method for manufacturing the composite board.

[0002]

2. Description of the Related Art In recent years, a large amount of lauan plywood has been used as a floor base material for which the amount of use has increased significantly.
This is closely related to the fact that raw raw wood growing in the rainforest region has been supplied more stably and cheaply compared to other materials even if there is a slight wave until recently.

Moreover, the lauan plywood produced from this lauan log has a smooth surface, dimensional stability against moisture,
Bending strength, ease of processing, light weight, durability, supply stability, price stability, material color stability, etc. were all excellent materials.

However, in recent years, there has been a growing demand for protection of the global environment, and the rapid depletion of tropical rainforests due to the deforestation of raw raw trees and other reasons has come to be accused of the world.

Therefore, the use of particle board, MDF (medium fiber board), softwood plywood, etc. has been studied as a material to replace Lauan plywood, but none of them has been replaced with Lauan plywood.

[0006] For example, in a particle board, dimensional stability against moisture, bending strength, easiness of processing, lightness, etc. are far below those of Lauan plywood. In addition, MDF, which has recently attracted attention, is far superior to Lauan plywood in terms of surface smoothness, but it is expensive and has very poor dimensional stability against moisture. It was still insufficient to secure it. Further, since the softwood plywood has the same structure as the Lauan plywood, dimensional stability, bending strength, ease of processing, and
Since it is possible to plant trees, it has excellent supply stability, etc., and is a material that is relatively close to Lauan plywood, but most conifers have many nodes and the difference in hardness (soft fall and spring wood) on the surface. However, the flatness of the surface was very poor, and it was difficult to directly adhere the name wood veneer or the decorative paper to the surface of the softwood plywood.

As described above, the particle board, M
Since it is very difficult to use DF, softwood plywood or the like alone instead of Lauan plywood, attempts have been made to use the above materials in combination. For example, MDF was heat-pressure-bonded to the surface of a softwood plywood or a thin particle board via an adhesive. However, in all cases, the four laps were warped upward after heat-pressing and tended to be just like a bowl. In this way, when the composite plate warped in a bowl shape is used as a floorboard, the surface is made up and the four edges are actually processed and nailed or glued, and the butt surface rises and becomes uneven, There was a defect that the makeup of the raised portion was worn away by abrasion, and the base material was exposed only in that portion, which was very unsightly.

Since the hot-pressing method warps like a bowl, it has been attempted to manufacture a composite plate by the cold-pressing method, but the adhesive used for the cold-pressing method is expensive, and moreover, to bond softwood by the cold-pressing method. Since a large amount of adhesive is required, the price of the composite plate becomes higher and higher, and there is a drawback that the adhesive protrudes from the edges. Further, the cold pressing method is much worse than the hot pressing method from the viewpoint of productivity, and there is a drawback in that when the surface of the manufactured composite plate is coated with the top coating material and dried, it also warps into a bowl shape.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a composite plate which has sufficient characteristics as an alternative material for lauan plywood and which eliminates the above-mentioned disadvantage of warping like a bowl. To do.

[00010]

In order to achieve the above object, the present invention is to laminate the MDF and the softwood plywood via an adhesive, and heat and pressurize the MDF so that the water content of the MDF is the water content of the softwood plywood. The present invention relates to a method for producing a composite plate, which is characterized in that it is set lower than the rate and the difference in shrinkage due to changes in the water content thereof is utilized. It should be noted that a nameplate veneer may be previously adhered to the surface of the MDF which is the uppermost layer, in which case the water content of the nameplate veneer attached MDF itself should be set lower than the water content of the softwood plywood. is necessary. Further, in order to manufacture the above composite board, MDF and softwood plywood may be laminated with an adhesive and heat pressed, but the above MD
Alternatively, F and a plurality of softwood veneers may be laminated with an adhesive, and the composite plates may be manufactured by hot pressing at once.

The present invention will be described below with reference to the accompanying drawings. 1 to 4 are perspective views showing respective manufacturing steps of the composite plate of the present invention. Reference numeral 1 is an MDF, and the thickness is preferably about 2 to 3 mm from the economical point of view, but the thickness is not limited to this. Further, as a raw material for MDF, there are a material using a softwood material, a material using a hardwood material, and a material using a mixture thereof, but any material may be used in the present invention. Also, MDF has a melamine type,
There are phenol-type, urea-type MDF, etc., but when used as a floor base plate, melamine-type or phenol-type MDF having excellent water resistance and heat resistance is preferable.
Of course, when used in places such as wall boards and ceiling boards that do not require much water resistance, urea type MDF
Good. The MDF is previously dried in a hot platen or a drying oven so that the water content is preferably 3% or less. Even if the water content of MDF exceeds 3%, the object of the present invention can be sufficiently achieved if there is a difference between the water content of MDF and that of softwood plywood. However, from the viewpoint of productivity, it is better to make it 3% or less. Because MD
This is because it is easier to control in terms of production when the water content of F is 3% or less, in other words, when it is close to an absolutely dry state. In FIGS. 3 and 4, the name wood veneer 2 is attached to the surface before drying, and in this case as well, the name wood veneer MDF is dried so that the water content is preferably 3% or less. When the nameplate veneer 2 is pasted on the surface in this way, there is an advantage that the plane tensile strength becomes larger than that when it is pasted. This is after drying the MDF and pasting the name wood veneer 2 on its surface,
This is probably because the surface of MDF is slightly deteriorated by heat. 3, 4 and 5 are softwood veneers, these veneers are
Although the fiber directions are shown as being orthogonal to each other, the present invention is not limited to this.

The softwood veneers 4, 5 and 6 may be in the form of plywood as shown in FIGS. 1 and 3 in the production of the composite plate, but as shown in FIGS. 2 and 4. The MDF 1 and the three softwood veneers 3, 4, and 5 may be combined into one composite sheet with an adhesive. When laminated and hot pressed, the water content of the softwood veneer is preferably almost air-dried even if there is some difference depending on the adhesive used. Here, the air-dry state refers to 6 to 15% although there are regional differences. This water content is also not limited to the air-dried state, but varies depending on the water content of MDF. However, it goes without saying that the air-dry state is preferable in view of productivity. Also,
The heat and pressure conditions are 110 ° C to 130 ° C, and pressure is 6 to 10 kg.
/ Cm ² , and the time is about 3 to 10 minutes, which is the same as or close to the conventional hot-pressing conditions during plywood manufacturing.

In the present invention, it is important that the water content of the MDF to be laminated is set lower than that of the softwood plywood, preferably 3% or less. By doing so, the composite plate produced does not warp in a bowl shape, but is in a substantially smooth state or in a slightly inverted bowl shape.

[0014]

Example 1 A melamine-type MDF made of a coniferous tree having a thickness of 2.7 mm as a raw material was dried in a heating plate at a temperature of 120 ° C. for 20 minutes to have a water content of 2%. Separately, the thickness is 1.
7mm radius tapin, 3.2mm thick as core plate
Radia tapain of 1.7 mm thick as a back plate, and a pressure of 8 mm is applied to the radial tapain via a urea melamine resin adhesive.
A softwood plywood having a water content of 12% was manufactured by hot pressing for 4 minutes under a hot pressing condition of kg / cm ² and a temperature of 120 ° C. The MDF adjusted to the above water content and the softwood plywood are laminated, and a pressure of 8 kg / cm ² and a temperature of 120 are applied via a urea melamine resin adhesive.
The size is 945mm × 1840mm after hot pressing at ℃ for 7 minutes.
The composite plate of 1 was formed, and this was divided into three to obtain the desired composite plate. The warp of this composite plate was measured 48 hours after production, and was 2.0 mm in the longitudinal direction and 1.0 m in the width direction.
Although it was warped like an inverted bowl, it was almost smooth as a whole. Incidentally, the numerical value indicating the ratio of the warp is a plus when the central portion is convex when the composite plate is placed on a horizontal plane, the distance between the central portion in the longitudinal direction and the horizontal plane, the central portion in the width direction and the horizontal plane. Was measured.

[0015]

[Example 2] A melamine-type MDF made of a coniferous tree having a thickness of 2.7 mm was adhered with a wood veneer having a thickness of 0.3 mm on the surface of the MDF, and the MDF was attached to the hot plate at a temperature of 120 ° C for 25 minutes. It was dried to a water content of 2%. Separately, the front plate has a thickness of 1.7 mm of radial tapine, the core plate has a thickness of 3.2 mm, and the back plate has a thickness of 1.
A softwood plywood having a water content of 12% was produced by pressing 7 mm of radia-tapain via a urea melamine resin adhesive under a pressure of 8 kg / cm ² and a temperature of 120 ° C. for 4 minutes.
The MDF adjusted to the above water content and the softwood plywood were laminated via a urea melamine resin adhesive, and the pressure was 8 kg / cm.
² , the size is 945mm by hot pressing at 120 ℃ for 7 minutes
A composite plate of x1840 mm was formed, and this was divided into three parts to obtain a desired composite plate. When the warp of this composite plate was measured after 48 hours, it was 4.0 mm in the longitudinal direction and 2.0 in the width direction.
mm Although it was warped like an inverted bowl, it was almost smooth as a whole.

[0016]

Example 3 A desired composite board was obtained in the same manner as in Example 1 except that a softwood plywood having a water content of 8% was used in place of the softwood plywood having a water content of 12% used in the first embodiment. When the warp of this composite plate was measured after 48 hours, it was found to be 3.0 mm in the longitudinal direction and 1.0 mm in the width direction in the shape of an inverted bowl, but it was almost smooth as a whole.

[0017]

Example 4 Instead of the coniferous plywood having a water content of 12% used in Example 1, a front plate, a core plate and a back plate each have a thickness of 1.7 mm, 3.2 mm and 1.7 mm and a water content of 12 respectively.
% Radia-tapine veneer is used, MDF and three pieces of Radia-tapine veneer are laminated with an adhesive, and pressure is 8 k.
A desired composite plate was obtained in the same manner as in Example 1 except that hot pressing was performed at g / cm ² and a temperature of 120 ° C. for 8 minutes. The warp of this composite plate was measured after 48 hours and found to be 2.0 in the longitudinal direction.
mm, and 0 in the width direction.

[0018]

[Example 5] A desired composite material was prepared in the same manner as in Example 2 except that the MDF laminated with wood veneer was dried in a hot air drying oven at a temperature of 120 ° C for 60 minutes to give a water content of 1.0%. I got a plate. The warp of this composite plate after 48 hours was 3.0 mm in the longitudinal direction and 2.0 mm in the width direction, and was warped in an inverted bowl shape, but it was almost smooth as a whole.

[0019]

[Embodiment 6] In Embodiment 2, the softwood plywood has a single plate thickness constitution of a front plate 3.2 mm, a core plate 3.2 mm, and a back plate 3.2.
A desired composite plate was obtained in the same manner as in Example 2 except that the thickness was changed to mm. The warp of this composite plate after 48 hours was 3.0 mm in the longitudinal direction and 1.0 mm in the width direction, and was warped in an inverted bowl shape, but it was almost smooth as a whole.

[0020]

[Example 7] In Example 2, the thickness of the MDF was set to 2.0.
A desired composite plate was obtained in the same manner as in Example 2 except that the thickness was changed to mm. The warp of this composite plate after 48 hours was 5.
Although it was warped like an inverted bowl at 0 mm and 3.0 mm in the width direction, it was almost smooth as a whole.

[0021]

[Example 8] Instead of the MDF having a water content of 2% used in Example 1, an MDF having a water content of 4% was used, and a softwood plywood having a water content of 11% was used instead of the softwood plywood having a water content of 12%. A desired composite plate was obtained in the same manner as in Example 1 except for the above.
When the warp of this composite plate was measured after 48 hours, it was found to be 2.0 mm in the longitudinal direction and 2.0 mm in the width direction in an inverted bowl shape, but it was almost smooth as a whole.

[0022]

[Embodiment 9] Instead of the MDF veneer with a moisture content of 2% used in Example 2, a MDF veneer with a moisture content of 6% was used.
A desired composite board was obtained in the same manner as in Example 2 except that a softwood plywood having a water content of 16% was used instead of the softwood plywood having a water content of 12%. When the warpage of this composite plate was measured after 48 hours, it was found to be 2.0 mm in the longitudinal direction and 1.0 mm in the width direction in the shape of an inverted bowl, but it was almost smooth as a whole.

[0023]

Comparative Example 1 In Example 1, the water content of MDF was 8%.
A composite plate was obtained in the same manner as in Example 1 except that When the warp of this composite plate was measured after 48 hours, it was -3.0 mm in the longitudinal direction and -8.0 mm in the width direction, and it was warped like a bowl. In addition, when the central portion was concave, the composite plate was turned to the back, and the values obtained by measuring the distance between the central portion in the longitudinal direction and the horizontal plane and the distance between the central portion in the width direction and the horizontal plane were given a minus sign.

[0024]

[Comparative Example 2] A composite board was obtained in the same manner as in Example 2 except that the water content of the MDF laminated with wood veneer was changed to 4% and the water content of the softwood plywood was changed to 6%. When the warpage of this composite plate was measured after 48 hours, it was -2 in the longitudinal direction.
It was 8.0 mm and -7.0 mm in the width direction, and was warped like a bowl.

[0025]

INDUSTRIAL APPLICABILITY As described above, the composite plate of the present invention has an advantage that a composite plate slightly warped in an inverted bowl shape or almost smooth can be obtained without using a hardwood veneer.

[Brief description of drawings]

FIG. 1 is a perspective view showing a manufacturing process of a composite plate according to the present invention.

FIG. 2 is a perspective view showing another manufacturing process of the composite plate according to the present invention.

FIG. 3 is a perspective view showing another manufacturing process of the composite plate according to the present invention.

FIG. 4 is a perspective view showing another manufacturing process of the composite plate according to the present invention.

[Explanation of symbols]

 1 MDF 2 Name wood veneer 3, 4, 5 Conifer veneer

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[Procedure amendment]

[Submission date] October 16, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

Claims (8)

[Claims] 1. When MDF and softwood plywood are laminated via an adhesive and heated and pressed, the water content of MDF is set lower than the water content of softwood plywood so that the water content changes. A method for manufacturing a composite plate, which utilizes the shrinkage difference involved. 2. The water content of MDF is set to 3% or less, and the water content of the softwood plywood is set to an air dry state.
A method for producing the composite plate described. 3. A name tree veneer attached MDF having a name tree veneer adhered to its surface and a softwood plywood are sequentially laminated with an adhesive,
When this is heated and pressed, the water content of the MDF attached to the name wood veneer is set to be lower than the water content of the softwood plywood, and the difference in shrinkage due to the change in the water content is used to produce a composite board. Method. 4. The method for producing a composite board according to claim 3, wherein the water content of the MDF attached to the name wood veneer is 3% or less, and the water content of the softwood plywood is air-dried. 5. The MDF and a plurality of softwood veneers are laminated via an adhesive, and when the MDF is heated and pressed, the water content of the MDF is set lower than that of the softwood veneer, A method for manufacturing a composite board, which utilizes a difference in shrinkage due to a change in water content of. 6. The water content of MDF is set to 3% or less, and the water content of the softwood veneer is set to an air dry state.
A method for producing the composite plate described. 7. A nameplate veneer-attached MD, in which a nameplate veneer-attached MDF and a plurality of softwood veneers are laminated one after another with an adhesive, and heat and pressure are applied to the same.
A method for producing a composite board, characterized in that the water content of F is set to be lower than the water content of a softwood veneer, and the difference in shrinkage due to changes in the water content is utilized. 8. The method for producing a composite board according to claim 7, wherein the water content of the MDF attached to the name wood veneer is 3% or less and the water content of the conifer veneer is air-dried.