JP2002127104A - Highly durable plywood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide highly durable plywood which has a fire prevention property and an antiseptic property and is good in dimensional stability. SOLUTION: A surface of wood veneer 2 is coated with cement paste containing cement based inorganic powder and thermosetting resin. A plurality of sheets of wood veneer 2 wherein the surfaces are respectively coated with the cement paste, are laminated to provide the plywood 1 which is cured by compacting and hardening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly durable plywood.

[0002]

2. Description of the Related Art Plywood is manufactured by laminating a plurality of pieces of wood veneer coated with an adhesive such as urea resin or phenol resin so that the fiber directions are alternately orthogonal to each other, and hot pressing. It is flammable and rotable, and has a large water absorption thickness swelling rate and water absorption linear expansion rate. Means for improving the disadvantages of the plywood include a structure in which a non-combustible and anticorrosive material layer is provided on the surface of the plywood (Japanese Patent Laid-Open No. Hei 10-237982). There has been provided a configuration in which the layers are laminated and bonded with an adhesive composed of a molecular weight phenol resin (Japanese Patent Application Laid-Open No. 8-332603).

[0003]

SUMMARY OF THE INVENTION Non-combustible only on the surface of plywood
Those provided with the anticorrosion material layer do not have sufficient incombustibility and anticorrosion properties, cannot be said to have sufficiently improved decay properties, and hardly improve the water absorption thickness swelling rate and the water absorption linear expansion rate. In addition, when a hole is punched in the surface of a veneer veneer and laminated and bonded with an adhesive composed of a low-molecular-weight phenol resin and a high-molecular-weight phenol resin, the low-molecular-weight phenol resin is impregnated and injected into the veneer from the side wall of the hole. Although the strength is improved and the dimensional stability is excellent, the flammability and decay property are not improved.

[0004]

According to the present invention, as a means for solving the above-mentioned conventional problems, a surface of a veneer veneer (2, 12) is coated with a cement paste containing a cement inorganic powder and a thermosetting resin. Further, the present invention provides a highly durable plywood (1, 11) obtained by laminating a plurality of wood veneers (2, 12) whose surfaces are coated with the cement paste and curing them by press hardening. The cement paste contains a cement-based inorganic powder and a thermosetting resin.
It is desirable that the wood veneer (2,12) has a large number of through holes (2A, 12A).
Are provided, and the cement paste is provided with the through holes (2A,
It is desirable to penetrate through 12A) and anchor to the upper and lower veneer veneers (2, 12). Further, it is desirable that fluff (2B, 12B) for anchoring exists on the surface of the wood veneer (2, 12).

[0005]

According to the present invention, a cement paste hardened layer (3, 13) exists between each veneer veneer (2, 12). The cement component in the hardened cement paste layer (3, 13) imparts incombustibility and antiseptic properties to the plywood (1, 11), and the thermosetting resin imparts strength and dimensional stability to the plywood (1, 11). Is given.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below.
The wood veneer used in the present invention is used for ordinary plywood manufactured by stripping raw wood thinly with a rotary lace or the like, and has a thickness of usually about 2 to 4 mm. If desired, the wood veneer may be provided with a large number of through-holes for penetrating the adhesive, and the surface may be made fluffy by a rotary brush, a belt sander or the like in order to enhance the anchoring effect of the adhesive.

Examples of the cement-based inorganic powder used in the cement paste of the present invention include Portland cement, blast furnace slag cement, silica cement, fly ash cement, alumina cement and the like. Examples of the thermosetting resin include a urethane resin, a melamine resin, a thermosetting acrylic resin, a urea resin, a phenol resin, an epoxy resin, a thermosetting polyester, and a urethane resin prepolymer produced by the synthetic resin in place of the above synthetic resin. And epoxy resin prepolymer, melamine resin prepolymer, urea resin prepolymer, phenol resin prepolymer, diallyl phthalate prepolymer, acrylic oligomer, polyvalent isocyanate and the like.

The cement-based inorganic powder and the thermosetting resin (solid content) are usually mixed in a weight ratio of 70:30 to 85:15 to form a paste using water as a medium. The water content is usually 40 to 60% by weight.

In order to manufacture a plywood, the above cement paste is usually applied to the surface of the veneer veneer in an amount of 50 g / m ^{2 to} 100 g / m ² , and a plurality of the veneer veneers are laminated and pressed. Let it cure. The pressing condition is usually 0.8 to 1.2M press pressure.
Pa, the pressing time is 3 to 7 minutes, and the pressing temperature is 100 to 140 ° C.

In the case of laminating the above-mentioned wood veneers, it is usually desirable that the fiber directions are alternately orthogonal to each other. Cement paste penetrates through holes and anchors to the upper and lower wood veneers to improve interlayer adhesion strength and dimensional stability.

Further, if fuzz is present on the surface of the wood veneer, the fuzz is anchored to the cement paste coating layer, and the interlayer adhesion strength and dimensional stability are improved.

[Example 1] Larch was used as a single veneer (2) having a thickness of 3.0 mm by rotary lace. After the surface of the wood veneer (2) is fuzzed (2B) with a belt sander, 5 cm is applied to the entire surface of the wood veneer (2) with a punching roll.
A large number of through holes (2A) having a diameter of 1 to 1.5 mm were provided at intervals. Portland cement: phenol resin (solid content) = 80: 20 weight ratio cement paste (water content 50%) was applied on the front and back surfaces of the wood veneer (2) at an application amount of 50 g / m ² . Three pieces of the above-mentioned wood veneer (2) are laminated and pressed at a pressure of 1.0M.
The plywood (1) was produced by pressing at 120 ° C. for 5 minutes at Pa and natural curing for 1 week.

In the plywood (1), when the cement paste is applied, the cement paste slightly penetrates into the through holes (2A) of the wood veneer (2). 2A) penetrates almost completely. The structure of the obtained plywood (1) is shown in FIG. In the plywood (1) shown in Fig. 1, the hardened cement paste layer (3)
(2) It intervenes and further penetrates through holes (2A) of each veneer veneer (2) and anchors to the upper and lower veneer veneers (2, 2). Further, the fuzz (2B) on the surface of each veneer (2) is anchored to the cement paste hardened layer (3).

[Example 2] When laminating larch wood as a single veneer (12) having a thickness of 3.0 mm with a rotary lace and fuzzing (12B) with a belt sander, three wooden veneers (12) are laminated. The three wood veneers (12) in the center are punched rolls and used as a wood veneer (12) provided with a large number of through holes (12A) (hole diameter is the same as in Example 1). A wood veneer (12) without a hole (12A) was used. Portland cement: isocyanate resin (solid content) = 75: 25 weight ratio cement paste (50% water content) was applied on the front and back surfaces of the three wood veneers (12) at an application amount of 50 g / m ² . . Three pieces of the above-mentioned wood veneer (12) are laminated, pressed at a pressure of 1.0 MPa for 5 minutes, then cured at 80 ° C. for 10 hours, and then further cured for 1 hour.
After natural curing for a week, plywood (11) was produced.

In the plywood (11), as in the first embodiment, the cement paste penetrates almost completely into the through hole (12A) of the central wood veneer (12) by pressing pressure at the time of pressing. The hardened cement paste layer (13) does not penetrate the wood veneer (12). FIG. 2 shows the structure of the obtained plywood (11). In the plywood (11) shown in FIG. 2, a hardened cement paste layer (13) is interposed between the wood veneers (12) and further penetrates through the through hole (12A) of the wood veneer (12) at the center. It is anchored on the upper and lower timber veneers (12,12). Further, the fuzz (12B) on the surface of each wood veneer (12) is anchored to the hardened cement paste layer (13).

Table 1 shows the measurement results of the physical properties of the plywoods (1, 11) of Examples 1 and 2. Larch plywood having a thickness of 9 mm was used as a comparative example.

[0017]

[Table 1]

According to Table 1, the bending strength and Young's modulus of the plywood (1,11) of the present invention are slightly larger than those of the conventional plywood, and the dimensional stability (water absorption thickness swelling ratio, water absorption line swelling ratio) of the plywood of the conventional plywood is high. It is remarkably improved as compared with the above, and it is recognized that fire resistance is also high.

[0019]

The highly durable plywood of the present invention has strength equal to or higher than that of the conventional plywood, has much higher dimensional stability than the conventional plywood, and has fire resistance and antiseptic properties. Also rich.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a plywood according to a first embodiment.

FIG. 2 is a cross-sectional view of a plywood according to a second embodiment.

[Description of Signs] 1,11 Plywood 2,12 Wood veneer 2A, 12A Through hole 2B, 12B Fluff 3,13 Hardened cement paste layer

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2B200 AA01 BA11 BA18 CA11 CA13 CA20 DA04 EA06 EC18 EE13 EF11 FA24 FA31 HA03 HB20 4F100 AE01B AK01B AK33B AP01A AP01C BA08 BA10A BA10C DC11A DC11C DD07A DD07JEJBEJ07J20EJ07 JL04 YY00B

Claims (4)

[Claims] 1. A surface of a veneer veneer is coated with a cement paste containing a cement-based inorganic powder and a thermosetting resin, and a plurality of veneer veneers whose surfaces are coated with the cement paste are laminated and pressed and cured. Characterized by high durability plywood 2. The highly durable plywood according to claim 1, wherein the cement paste contains a cement-based inorganic powder and a thermosetting resin in a weight ratio of 70:30 to 85:15. 3. The wood veneer according to claim 1, wherein the veneer has a plurality of through-holes, and the cement paste penetrates through the through-holes and is anchored on upper and lower veneer veneers. Highly durable plywood 4. A highly durable plywood according to claim 1, wherein the surface of said veneer has fluff for anchoring.