JPS5870796A - Production of fiberboard having multilayer structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a fiberboard having a multilayer structure with excellent impact resistance, bending resistance, tensile strength, etc. by wet papermaking.

Traditionally, wood fiberboards have been made from so-called 7℃ mechanical pulp (TMP), which is made by steaming wood chips and then defibrating them using a disc refiner, and has excellent heat insulation properties and workability. In addition, it is possible to manufacture relatively thick products in just one round of papermaking, and by changing conditions such as press pressure during manufacturing, it can be used for insulation materials, construction materials, furniture panels, packaging materials, and bases for various molding materials. However, fiberboard made only of thermomechanical pulp has poor bending and impact resistance compared to other wood materials at the same specific gravity. Therefore, in order to obtain the desired strength, it is necessary to use a thicker material or a material with a higher specific gravity. Development of a board is desired.

On the other hand, as a method to eliminate the strength defects of wood fiberboards, it is also common to manufacture mechanical valves by mixing long fiber materials with excellent tensile strength such as hemp fibers and synthetic fibers. It has been proposed that when papermaking a fiber mat made by mixing and dispersing a long fiber material into a mechanical pulp, conditions such as the papermaking speed may be changed depending on the amount of the long fiber material added, and the type and amount of bicedar etc. Troublesome operations such as changing the fiberboard are required, and the strength performance of the obtained fiberboard only improves gradually depending on the amount of the fiberboard mixed, and no dramatic improvement can be expected.

Furthermore, for various industrial materials such as building materials, furniture materials, packaging materials, molding base materials, etc., it may not be sufficient to simply improve the strength, depending on the application and the area of use. Various properties such as smoothness, bendability, bending resistance, and surface impact resistance are often required), and it is possible to form a fiberboard with physical properties that meet these required performances in a one-step production-like process. It was extremely difficult to do so.

In order to eliminate such drawbacks and problems, the present invention forms a laminated mat by combining a wet mat formed from a mechanical pulp with a fibrous slurry mainly made of long fiber material, The present invention provides a method for producing a fiberboard having a novel multilayer structure that satisfies the above requirements by laminating, heating, pressing, and integrating a plurality of mats without drying them.

The embodiments of the present invention will be explained with reference to the drawings.
As shown in the figure, a wet mat (1) of a desired thickness is formed by forming a slurry (1a) mainly composed of thermomechanical pulp using a circular mesh paper machine, and at the same time, the surface of the formed mat is In addition, a fibrous slurry (2
a) are combined and a long fiber material layer (
A laminated mat (8) provided with 2) is formed.

Slurry mainly composed of thermomechanical pulp (1&)
If necessary, a small amount of binder or starch is added as a binder, and a small amount of a fibrous material such as waste paper or synthetic fiber, or a sizing agent such as wax or the like is also added.

As for the paper-combining method, as shown in the figure, in addition to the method of pouring the fibrous slurry (block) directly onto the wet mat (1) and combining the paper-sheets, there is also a method of forming the paper using a separate fourdrinier machine, etc. A method may be adopted in which a wet sheet of long fiber material is placed on the wet mat (1) and then kneaded together.

Also, when combining paper like this, wet mat (1)
, and a suitable adhesive (4) at the interface with the long fiber material layer (2).
may be applied with a sprayer (5) or the like to increase the bonding strength between the two.

Next, the thus laminated mat (8) is cut into appropriate lengths, and without drying, the cut laminated mats (21a) (3a) are stacked one on top of the other. The laminated body (6) is inserted between the hot platens (7) and (8) of a hot press, and is heated and pressed to integrate the laminated body (6).

At this time, the lamination state of the plurality of laminated mats (8a) (3a) can be arbitrarily determined depending on the purpose of use of the fiberboard to be obtained, and further depending on the long fiber material used to combine the fiberboards. For example, long fiber materials such as kraft pulp with long fiber length and strong tensile strength can be used. When trying to obtain a material with excellent surface smoothness and bending strength by using Calpulp, as shown in Figure 1, multiple layers of long fiber material (2) are placed on the top side. Mat (8
a) (8a) are stacked together, or as shown in Figure 2, the laminated mat (8a/aa) of the outermost layer is laminated with the long fiber material layers (2) (2) on the outer side, and heated and pressed. It is something that unifies. In this case, if a laminated mat made of synthetic fibers alone or mixed with kraft pulp or the like is used as the long fiber material, a fiberboard with improved surface water resistance and absorbency can be obtained.

Furthermore, as shown in Fig. 3, the long fiber material layer <2) (2)
The laminated mats (aa) and (aa) may be laminated and integrated, with each mat facing the inner surface. In particular, when a material that irritates the skin such as glass fiber is used as the long fiber material, the long fiber material layer (2) is obtained.
It is preferable for handling to form a fiberboard having a structure in which (2) is arranged on the inner surface side.

After overlapping the laminated mats (8a) (8a), as described above, they are inserted between the Hontsu and Dobres heating plates ()) (8) and heated and pressed until the specific gravity becomes 0.4 to 10. Unlike when dry fiberboard is pressed and bonded, each laminated mat (
8a) The fibers at the interface of (8a) become entangled and integrated due to the movement of water, etc., and the fibers forming each laminated mat (8a) (85L) are combined. Mechanical,
A fiberboard with a multilayer structure in which the interlayers are integrated by intertwining of fibers can be obtained.

In addition, when stacking multiple laminated mats (8a),
The laminated mats (8a) are laminated by applying an adhesive to the interface of the laminated mats (8a), and then heated and pressed.
The bonding strength between a) and (3a) is further increased, and the strength performance can be further improved.

Furthermore, the thickness of the long fiber material layer (2) of the laminated mat is '
The supply speed of the slurry (2a) can be freely determined depending on the use of the fiberboard, so it is not particularly limited, but at least 60 f/.

It is preferable to combine the sheets in the above manner, as this prevents the formation of irregularities and increases the strength.

Next, specific examples and comparative examples of the present invention will be shown.

Example A slurry prepared by mixing 98 parts of thermomechanical pulp (TMP), 2 parts of phenolic resin, and 15 parts of sulfuric acid was made into paper using a circular mesh paper machine, and the amount of fiber was made into g.
o o o A wet mat of 7wt was formed, and on this wet mat, a pulp slurry prepared by mixing 98 parts of softwood kraft pulp, 2 parts of phenolic resin, and 15 parts of sulfuric acid was mixed in an amount Z 00'. /,
The laminated mats obtained by cutting the mats into appropriate sizes are stacked with the long fiber material layer facing upward without drying, and heated to 18 cm by hot pressing.
After heating and pressurizing for 1 minute at 0°C and 20'//,
Heat and press for 9 minutes at 0℃ and 5 to 5 to make specific gravity 0.8, thickness &5
A fiberboard consisting of four layers of snow (mechanical pulp thickness 2-5XS, long fiber material layer thickness α25X2) was obtained.

On the other hand, as Comparative Example A, a slurry mainly composed of the thermomechanical pulp, that is, thermomechanical pulp (
TMP) 98m, 2 parts of phenolic resin, 15% of sulfuric acid
A wet mat made from only a slurry of
．． A 5M fiberboard was formed. Also, as a comparative example B, thermomechanical pulp (TMP) was used.
) 89.1 parts, 19 parts of softwood kraft pulp, 2 parts of phenolic resin, and 15 parts of sulfuric acid soap were mixed to prepare a wet mat with a fiber content of 4400'/. A fiberboard having a specific gravity of 0.8 and a thickness of 5 cm was formed by heating and pressing under the following conditions.

The physical properties of Examples and Comparative Examples A and B thus obtained are shown below. However, in the example, the long fiber material layer was placed on the tension side for testing.

Example aa 845 14. )4 Comparative example A
aa 272 101 Comparative example B aa
295 111 As is clear from the table above, the fiberboards obtained in the Examples of the present invention are superior to the two-fiberboards of Comparative Examples A and B in terms of both bending strength and impact resistance. It showed the physical properties.

As described above, the present invention provides a wet mat made of thermomechanical pulp, on at least one side of which is coated with a fibrous material mainly consisting of a long fiber material consisting of kraft pulp, cotton fiber, synthetic fiber, glass wool alone or in a mixture thereof. A method for producing a fiberboard having a multilayer structure, which comprises: mixing slurry to form a laminated mat, and then laminating a plurality of the laminated mats without drying them and heat-pressing them to integrate them. Therefore, it is possible to easily obtain a fiberboard with excellent strength and impact resistance by integrating thermomechanical pulp and long fiber material layers in multiple layers. By placing the layer on the surface, it is possible to form a fiberboard with excellent surface appearance, smoothness, and bending processability, while by placing the long fiber material layer as the inner layer, it is possible to form a fiberboard with excellent bending resistance. , it is possible to easily obtain a fiberboard having physical properties that meet the desired performance.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a simplified side view showing the manufacturing process thereof, and FIGS. 2 and 3 are explanatory diagrams showing different overlapping states of the laminated mat. (1) Wet mat, (2) Long fiber material layer, (8a) Fist/laminate mat, (6) Φ laminate. Patent applicant Daiken Kogyo Co., Ltd. Representative Patent Attorney Abe Nakao 1
Inkstone E=====Yo) Pe Z Iris) A j degree

Claims (1)

[Scope of Claims] ■' At least one side of a wet mat made from mechanical pulp in a paper machine is mainly made of a long-fiber material consisting of kraft pulp, cotton fiber, synthetic fiber, or clay wool alone or in a mixture thereof. A fiberboard having a multilayer structure characterized in that a fibrous slurry is mixed together to form a laminated mat, and then a plurality of the laminated mats are laminated without drying and heat-pressed and integrated. Production method. (2) A method for manufacturing a fiberboard having a multilayer structure according to claim 1, characterized in that the laminated MAPTs are laminated and integrated by applying an adhesive to their interfaces. (2) Manufacturing a fiberboard having a multilayer structure according to claim 1 or 2, characterized in that at least one of the long fiber material layers of the laminated mat is laminated and integrated so that it is on the outside surface side of the filter. Method. (2) A method for manufacturing a fiberboard having a multilayer structure according to claim 1 or 2, characterized in that the laminated mat is laminated and integrated so that the long fiber material layer faces the inner surface. ■Claims 1, 2, and 3 are characterized in that they are heated and pressed until the overall specific gravity becomes 0.4 to 10.
A method for producing a fiberboard having a multilayer structure according to item 1 or 1.