JPH08290410A - Artificial lumber and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide an artificial lumber with high strength, particularly with high water absorption strength, and also provide a manufacture thereof. CONSTITUTION: This method is manufacture an artificial lumber by compression forming lumber powder having a binder added therein, wherein the lumber powder is crashed and sorted into a coarse grain lumber powder and a fine grain lumber powder having an average grain diameter of 1/3 to 1/10 of an average grain diameter of the coarse grain lumber powder, that is, a manufacture of high strength artificial lumber for accelerating the densest filling of mutual lumbers by adding a fine grain lumber powder of 10-60 pts.wt. to a coarse grain lumber powder of 100 pts.wt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is an industrially indispensable but inexpensive high-strength artificial wood substitute for high-strength wood such as pine, yakar and the like, which have a slow growing tendency in the world and tend to be manufactured. Regarding the method.

[0002]

2. Description of the Related Art As artificial wood, commercially available are particle boards made mainly from cut wood pieces, fiberboard made mainly from woven pulp. However, they are weak in strength, and in particular have extremely low water absorption strength, and therefore cannot be used as substitutes for high-strength wood for outdoor use, such as wood used in shipyards and pallets laid on the bottom of heavy loads.

[0003]

[Problems to be Solved by the Invention]

1) Improvement of strength, especially water absorption strength Conventional artificial wood is often used for interior wall materials of houses and furniture furniture, so high strength is not required so much, and water absorption strength is also a problem for indoor use. It wasn't.
As a result of actually purchasing a commercially available fiberboard having excellent strength and performing a strength test, the dry bending strength is 300-
Although it was 500 kg / cm ² , the water absorption strength could not be measured in a “battered” state where it was broken by hand after absorbing water. 2) Cost reduction and mass production The pine and yakar used for the above-mentioned deck boards are quite expensive, and there is a strong tendency to ban logging from the point of view of nature conservation at import destinations such as North America, making it difficult to obtain them. is there.

3) Reduction of Directional Deviation of Strength Natural wood has greatly different strengths in the direction of annual rings, that is, in the direction of the normal grain and the direction of the grain. As a result, a large amount of waste material is generated, and field workers are also very careful. It is an object of the present invention to solve the above problems and provide an artificial wood excellent in strength, especially water absorption strength, and a manufacturing method capable of manufacturing the artificial wood at a reduced cost.

[0005]

[Means for Solving the Problems] The above-mentioned object is a method for producing artificial wood by compression-molding wood powder to which a binder is added. 3-
Pulverize and classify into fine wood flour having an average particle size of 1/10,
A method for producing high-strength artificial wood, characterized in that 10 to 60 parts by weight of fine wood powder is added to 100 parts by weight of coarse wood powder to promote close packing of the wood powders, and a tree to which a binder is added In artificial wood obtained by compression-molding powder, the wood powder is 1/3 to 1/10 of the average particle size of the coarse wood powder with respect to 100 parts by weight of the coarse wood powder and the coarse wood powder. This can be achieved by high-strength artificial wood obtained by adding 10 to 60 parts by weight of fine wood powder having an average particle diameter to promote mutual close packing of wood powder.

The wood used as the raw material for the wood powder used herein may be of any type, including natural wood, waste wood generated from dismantled houses and sawmills, fallen trees, dead pine trees, cedar and lauan. Etc. are used, and examples of the thermosetting resin that is added as necessary include epoxy-based and polyester-based waste FRP. Further, among the wood flours, the average particle size distributions of the coarse grain wood powder and the fine grain wood powder are 100 to 500 μm and 10 respectively.
It is preferable to use those having a particle size of ˜50 μm, and particularly, it is necessary that the average particle size of the fine grain wood powder is 1/3 to 1/10 of the coarse grain wood powder. The average particle size of the thermosetting resin is preferably in the range of 3 to 30 μm, and the compounding amount thereof is preferably 30 to 70 parts by weight with respect to 100 parts by weight of the total amount of wood powder.

Further, in the present invention, the crushed coarse grain wood powder, crushed fine grain wood powder, and crushed thermosetting resin fine particles can be produced by one pass wet continuous crushing with one crusher. Such a crushing process is performed using, for example, a device (Mitsubishi Ultra Fine Mill-hereinafter referred to as UF mill) as shown in FIG. A UF mill has an inner cylinder and an outer cylinder equipped with a stirring blade, and the gap between them is filled with crushing balls.
Rotate the inner and outer cylinders individually or simultaneously,
It is a horizontal ultra-fine grain mill that continuously pulverizes and continuously discharges the supplied powder or powder slurry.

FIG. 4 illustrates an operation system in which the inner cylinder of the UF mill is independently rotated to perform wet continuous pulverization. The material to be crushed is continuously supplied from the raw material hopper 1 to the UF mill, and the slurry medium liquid (water in the case of the present invention) is continuously supplied from the tank 3 to the UF mill by the supply pump 4. The fine-grained slurry crushed by the crushing balls 7 filled in the gap between the UF mill outer cylinder 5 and the rotating UF mill inner cylinder 6 is separated from the crushing balls by the discharge slit 8 provided concentrically around the mill end. Only the pulverized powder is continuously discharged and collected in the product tank 9. According to this method, the coarsely pulverized wood powder, the finely pulverized wood powder, and the finely pulverized thermosetting resin are continuously pulverized by separate pulverizers, and are uniformly mixed and dispersed in the subsequent step, which is required for the production equipment. The cost can be reduced.

Furthermore, in a preferred embodiment of the present invention, in operating the UF mill, the feed port 10 for raw wood flour and FRP is arranged from the upstream side to the downstream side of the flow of the pulverized material in FIG. By changing the residence time in the mill and adjusting the crushed particle size, the crushed slurry of two types of raw materials (wood flour, FRP) and 3 particle sizes (2 types of wood flour, 1 type of FRP) It is possible to continuously manufacture one unit. Further, the uniform mixing and dispersion of the pulverized powder with three particle diameters can be continuously processed by one mill due to the random stirring effect of the inner cylinder of the UF mill, the outer cylinder stirring blades and the crushing balls.

[0010]

The present invention will be described in more detail below. (1) Improvement of strength, especially water absorption strength By mixing coarse-grained wood powder and fine-grained wood powder, fine-grained wood powder enters the voids of coarse-grained wood powder, so-called "closest packing structure" between wood powders. By forming it, the denseness is greatly improved, which improves the overall strength. Furthermore, by adding a thermosetting resin that is thinner than the fine wood powder, the resin powder enters the fine wood powder voids to further promote the close-packed structure, and at the same time the resin powder is hardened by the heat during compression molding. Strength and rigidity can be improved. An isocyanate-based binder having strong water repellency is used as a binder for adhering the wood powders to each other. Due to the water repellency of this binder and the denseness due to the close-packed structure, the water absorption rate of the final product can be greatly reduced and the water absorption strength is improved.

(2) Cost reduction and mass production In recent years, fallen trees due to typhoons and standing dead trees around large cities due to waste gas (SO ₃ etc.) have increased, and effective use is urgently required from the viewpoint of preventing secondary disasters. ing. In addition, the treatment of waste FRP ships, which are FRP products that are representative of thermosetting resins, and waste baths has become a major social issue. Since the present invention can use waste wood and waste FRP, which are generated in large quantities and have awaiting effective treatment, as main raw materials, they are inexpensive because they are artificial wood and can be mass-produced. It also has great social significance in terms of recycling. (3) Reduction of Directional Deviation of Strength Since the present invention is basically based on a uniform close packing structure of coarse grain wood powder, fine grain wood powder and FRP powder, the direction of strength does not greatly depend on the direction of the annual ring. Gender deviation can be significantly reduced.

<Optimal Particle Size Ratio and Optimal Mixing Ratio for Forming Closest Packing Structure> The optimum particle size ratio for closest packing can be theoretically studied in the case of a true sphere, but fibrous wood In the case of powder, theoretical examination was difficult and experimental examination was conducted. The curve [I] in Fig. 2 shows the average particle size (D ₅₀ ) _S of fine wood and the average particle size (D) of coarse wood.
Shows the relationship between the ₅₀₎ the ratio α _{[= (D 50) S / (} D 50) B ] and _B and prototype compressive strength ratio of the artificial timber. still,
The mixing ratio β of fine wood (fine wood / coarse wood), the amount of binder added, the molding conditions, etc. were all constant. The curve [II] shows the ratio of the average particle size (D ₅₀ ) _F and (D ₅₀ ) _S of the FRP powder. As is clear from FIG. 2, the strength is remarkably increased as α is decreased, and this is due to the effect of forming the close-packed structure in which the fine-grained wood enters the voids of the coarse-grained wood.
When FRP powder was mixed in, the strength was improved by about 40% due to its thermosetting effect. Furthermore, the appropriate value of α is 1/3 or less from the viewpoint of strength, 1/10 or more from the prevention of increase in crushing power,
That is, α = 1/3 to 1/10 was judged to be appropriate.

FIG. 3 shows the test of the influence of the mixture ratio β with α = 1/6 constant. In the curve [III] in which FRP powder was not mixed, β = 0.1 to 0.6 was judged to be appropriate.
The porosity at the time of filling the true sphere is 20 to 40%, but it is presumed that the wood powder is fibrous and the proper range is expanded due to compression molding. In the case of the FRP powder mixture curve [IV], the strength increases as the FRP powder mixture rate increases, but F
Since the crushing power of the RP powder is considerably large, the incorporation of 60% by weight or more causes a high cost, so β = 0.2 to 0.5 is appropriate.

[0014]

EXAMPLES The present invention will now be described in more detail with reference to examples. (Example 1) FIG. 1 is a flow sheet schematically showing the method of the present invention. As the waste wood, lauan wood generated at the time of demolishing a house was used as a raw material and pulverized into coarse wood powder having an average particle size of 150 μm and fine wood powder having an average particle size of 25 μm. The waste FRP was crushed 5 μm FRP powder from a waste tub discharged from households as coarse garbage. As the binder, a water-repellent isocyanate type (manufactured by Oshika Shinko Co., Ltd.) was used. The mixing ratio is 100 for coarse wood flour and 3 for fine wood flour.
0, FRP powder 30, and binder 5 (all in% by weight). After uniformly mixing and stirring these four types of materials, a heating compression molding machine (pressure 15 kg / cm ² , temperature 150 ° C.)
Made into artificial wood. The characteristics of the obtained artificial wood are shown in Table 1. Table 1 also shows the characteristic values of natural pine wood and commercial artificial wood.

[0015]

[Table 1]

(Embodiment 2) Using the UF mill shown in FIG. 5, the raw material hoppers 11, 12 and 13 are filled with FRP crushed raw material, wood flour raw material (for fine powder) and wood flour raw material (for coarse powder), respectively. did. As shown in FIG. 5, the positions of the supply ports for the various raw material powders were set to L _P , the distance from the discharge port in the flow direction of the crushed material,
It was installed so that it would be L _WS and L _WB . Since it is necessary to increase the residence time in the mill for finer pulverization, the position of the supply port is set to be L _P > L _WS > L _WB and apart from the discharge port. FIG. 6 shows a schematic diagram of each crushing characteristic when wood powder and FRP powder were crushed under the same operating conditions (mill rotation number, ball amount (rate), etc.) in a UF mill batch (batch type) crushing test. During batch grinding, finer powder is obtained as the grinding time is longer as shown in the figure. Required for artificial wood production,
Coarse grain wood grain size is D _WB , required crushing time is t _WB , fine grain wood grain size is D _WS , required crushing time is t _WS , FRP powder grain size is D _P ,
When the required crushing time is t _P , the required crushing time is t _WB :
_{t WS: t P = 1:} 4: was 8. These results are shown in FIG.
In order to reflect it in the conditions of continuous pulverization such as the above, the required pulverized particle size can be obtained by adjusting the required pulverizing time and the residence time in the mill. The ratio of batch crushing time should be set. Therefore, in order to make the particle size and the mixing ratio of the raw material powder shown in Table 2 below, UF
The position of the supply port of the three grinding raw mill L _WB: L _WS: L _P
= 1: 4: 8, the target artificial wood was dried and the slurry before molding was continuously produced by one-stage crushing.

[0017]

[Table 2]

[0018]

As described above, the artificial wood obtained by the method of the present invention has the following excellent properties: (1) The strength, especially the water absorption strength is remarkably excellent as compared with the conventional commercial artificial wood. ) It has almost the same strength as natural pine wood, the direction of strength is small, and it is better than natural pine wood at the weakest strength. (3) Waste wood such as fallen trees and standing dead trees is difficult to treat and society Waste FRP products in question (waste FRP ships, waste bathtubs)
Since it is used as the main raw material, it can be manufactured at low cost and has great social significance in terms of recycling waste. (4) In particular, when using a UF mill, the manufacturing cost can be significantly reduced (almost half of the conventional method).

[Brief description of drawings]

FIG. 1 is a flow sheet diagram showing an example of a manufacturing process according to a method of the present invention,

FIG. 2 is a graph showing the relationship between the average particle size ratio of raw materials and the strength ratio of artificial wood obtained by the method of the present invention.

FIG. 3 is a graph showing the relationship between the mixing ratio of raw materials and the strength ratio of artificial wood obtained by the method of the present invention,

FIG. 4 is a conceptual diagram showing a one-pass wet continuous crushing apparatus using a UF mill.

FIG. 5 is a schematic diagram illustrating a means for adjusting a pulverized particle size by changing the arrangement of raw material supply ports;

FIG. 6 is a graph showing respective grinding characteristics when wood powder and FRP powder are ground in a UF mill batch grinding test.

[Explanation of symbols]

 1: Raw material hopper 2: Feeder 3: Tank 4: Supply pump 5: UF mill outer cylinder 6: UF mill inner cylinder 7: Grinding ball 8: Discharge slit 9: Product tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Tsunoda 5-717-1, Fukahori-cho, Nagasaki-shi, Nagasaki Sanryo Heavy Industries Ltd. Nagasaki Research Institute

Claims (9)

[Claims] 1. A method for producing artificial wood by compression-molding wood powder to which a binder is added, wherein coarse wood powder and an average particle diameter of 1/3 to 1/10 of the average particle diameter of the coarse wood powder. High-strength characterized by crushing and classifying into fine grain wood powder having, and adding 10 to 60 parts by weight of fine grain wood powder to 100 parts by weight of coarse grain wood powder to promote close packing of the wood flour with each other. Manufacturing method of artificial wood. 2. The method for producing a high-strength artificial wood according to claim 1, wherein the thermosetting resin powder having an average particle diameter of 1/3 to 1/10 of the average particle diameter of the fine grain wood powder is added to increase the rigidity. . 3. A waste wood such as a fallen tree, a standing dead tree or a house dismantled timber is used as a wood powder raw material, and waste FRP generated in a large amount from a waste ship or a waste bath is used as a thermosetting resin raw material. 2. The method for producing a high-strength artificial wood according to 2. 4. A wood flour raw material is pulverized and classified into a coarse wood flour and a fine wood flour having an average child particle size of 1/10 to 1/3 of the average particle diameter of the coarse wood powder by a wet pulverization treatment. , Coarse grain 100
A heat having an average particle size of 1/10 to 1/3 of the average particle size of the fine grain wood powder is promoted by adding 10 to 60 parts by weight of the fine grain wood powder to the weight part to promote close packing of the fine grain wood powders. In a method for manufacturing artificial wood, which comprises adding a curable resin powder to increase rigidity, crushed coarse-grain wood powder / fine-grain wood powder and crushed thermosetting resin fine particles are continuously wet-processed in one pass with a single crusher. A method for producing high-strength artificial wood, characterized by: 5. The residence time inside the crusher is adjusted by installing a crushing raw material supply point to the crusher at an arbitrary position from the upstream side to the downstream side, and the FRP powder, the fine powder wood and the coarse powder wood are adjusted. The method for producing high-strength artificial wood according to claim 4, wherein the slurry uniformly mixed / dispersed is continuously wet-produced by one crusher in one pass. 6. The method according to claim 4 or 5, wherein waste wood such as fallen wood, standing dead tree or timber dismantled wood is used as a wood powder raw material, and waste FRP generated in a large amount from a waste ship or a waste bath is used as a thermosetting resin raw material. A method for producing the high-strength artificial wood described. 7. An artificial wood obtained by compression-molding wood powder to which a binder is added, wherein the wood powder is coarse-grain wood powder and the average grain size of the coarse-grain wood flour is 100 parts by weight of the coarse-grain wood flour. 1/3 of the diameter
A high-strength artificial wood obtained by adding 10 to 60 parts by weight of fine wood powder having an average particle diameter of ˜1 / 10 to promote close packing of wood powder. 8. The high-strength artificial wood according to claim 7, further comprising a thermosetting resin powder having an average particle diameter of 1/3 to 1/10 of the average particle diameter of fine wood powder. 9. A waste wood such as a fallen tree, a standing dead tree or a house dismantled timber is used as a wood powder raw material, and a large amount of waste FRP generated from a waste ship or a waste bath is used as a thermosetting resin raw material for a binder. Item 7. The high-strength artificial wood according to item 7 or 8.