JPS5829601A - Manufacture of veneer laminated board - 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 manufacturing veneer M-layer boards such as plywood and L V L, and its main purpose is to save the thermal energy required for drying the veneer and to improve the productivity of the laminate. The aim is to improve

Conventionally, plywood, L V L, etc. F board laminates are made from veneers obtained by peeling raw wood, which are forcibly dried to a moisture content of 15% or less, and then bonded again with a synthetic resin adhesive such as urea, melamine, or phenol. It was made by bonding with heat and pressure using a press or the like.

However, in the above conventional method, the process that requires the most thermal energy is the drying process of the veneer, so the production capacity of the laminate is generally determined by the capacity of the dryer, and the product cost is reduced to 1. Fuel costs were also very high.

In addition, most dryers are of the heat HA circulation type, which heats air by burning steam, hot water, or propane gas, and then blows the heated air onto the veneer surface to dry it. However, problems such as variation in moisture content within the veneer and drying shrinkage of the veneer have not been fully resolved.

Therefore, the present invention solves the above-mentioned problems by fundamentally changing the technical concept of the conventional method of manufacturing a veneer laminate.

In other words, the present invention cuts and shapes the veneer obtained by scraping raw wood into the required dimensions without forcing drying, and then /! li! They are laminated with a curable synthetic resin adhesive that can be bonded on a moist surface, and then pressed and bonded at room temperature to form a laminate, and then the laminate is heat-pressed to accelerate the curing of the adhesive described in Part 2. U.J., F.I.
The method for manufacturing veneer laminates is characterized by reducing the moisture content of the board to the level of the parallel moisture content in the atmosphere, and its most distinctive feature is the forced drying of a wet veneer with a high moisture content. After bonding using an adhesive that can be bonded on a wet surface, the laminate is heated and pressed to accelerate the curing of the adhesive, lower the moisture content of the laminate, and then dry the laminate.

The method of the great invention will be explained in more detail below.

First, lauan, powder, or other commonly used raw wood is peeled using a cutting machine such as a rotary lace, slicer, or half rotary to create a laminated material. 0.2-3.0m depending on configuration
It is about m. The small board should be forcibly dried using a dryer, etc.] Cut it to the required size while still wet, and then cut it to the required size and then dry it with plywood or lv1. , let's manufacture it.
Prepare a plan according to the product you are trying to manufacture. The moisture content is usually above the fiber saturation point. Then apply it to one or both sides of the veneer. l'l! Apply a wet surface bondable surface bondable synthetic resin adhesive. The synthetic resin adhesive capable of wet surface adhesion used in the present invention is a moisture-curing type urethane resin, a two-component urethane resin containing a polyol and a polyinone anar I compound, or a hardening agent made of polyamide, polysulfide, and aliphatic polyamine. Adhesives such as two-component Evokin resin, melamine, urea, phenol, benz'guanamine, acetoguanamine, and other powder adhesives with water removed from the resin can be used alone, or polyhinyl alcohol can be added to these powder adhesives. Adhesives mixed with re-wetting adhesives such as blood powder or starch, and also at specified temperatures (100°C to 120°C)
It is a microcapsule-containing thermosetting adhesive that hardens and exhibits adhesive strength when the temperature is below .

These adhesives are applied to the veneer using a coating device such as a spreader or sprayer.

Next, stack the required number of veneers. For example, when manufacturing plywood, an odd number of veneers are made into a set so that the fiber directions of the veneers are perpendicular, and in the case of L V L, multiple veneers are stacked as one silk so that the fiber directions of the veneers are parallel. Come together. Next, the first veneers were stacked together from several dozen sets to 2008n.
Tighten each piece under #J rule and glue. The pressing conditions are 5 to 10 kg/crA for about 30 minutes to 5 hours. For the clamping method, a device such as a cold press is used. Next, the bonded laminates are inserted between hot platens such as a Hoso i press and hot pressed. As a pressing device, a large number of narrow grooves are formed on the surface of the heating plate, or a pressing plate with a large number of narrow sizes such as a wire mesh is used to press the plate, allowing water vapor generated from the laminate to escape to the outside of the heating plate. During the tightening cycle, the laminate is initially heated under no pressure to generate as much water vapor as possible in the laminate, while gradually applying pressure.
The pressure is removed repeatedly and finally the load is applied to a predetermined pressure to prevent the occurrence of a puncture. An example of press conditions is shown in the drawing.

Note that the temperature of the heater is preferably in the range of about 100 to 120°C.

The following method is used to heat-press the laminate to accelerate the curing of the adhesive in the laminate, reduce the moisture content, and dry it to about 10 to 15%, which is approximately the equilibrium moisture content in the atmosphere. Obtain a board laminate.

As described above, the present invention has the following effects.

(1) Since drying is performed by directly applying heat without compaction using a heating device, the loss of heat required for drying veneers and laminates is less than that of drying with conventional dryers that use hot air, and it is more efficient.

(2) Since it is dried under pressure, the shrinkage loss in the width and length directions of veneers and laminates is smaller than that of conventional dryer drying, resulting in a high product yield.

(3) Since drying is performed under pressure, there are fewer cracks and cracks in veneers and laminates compared to conventional dryer drying, and the board surface is smooth and there is less variation in moisture content.

Examples of the present invention are not shown below.

Example ()) Lauan logs were stripped to obtain rotary veneers with a thickness of 1.3 mm for the core board and 0.6 mm for the front and car. The moisture content of the veneer was about 50-60%. Apply 100 g/m of moisture-curing urethane resin adhesive to both sides of the inner core board veneers of those veneers.
It was coated and layered with front and facing veneers on both sides so that the fiber directions were perpendicular to each other. Next, 200 veneers made of these
41 was pressed into one pile at a pressure of 10 kg/cnt-] at room temperature to obtain plywood with a high moisture content. Next, these plywoods were inserted into a hot press and hot-pressed under conditions of 110' CI2 kg/cnt using the press cycle shown in the drawings to produce plywood having the desired moisture content of 13%.

Example (2) A rotary veneer having a thickness of 2.0 parts was obtained by scraping hemlock logs. The moisture content of the veneer was about 40-50%. Powdered benzene guanamine resin adhesive 100% on the surface of the veneer.
50 parts by weight of adhesive mixed with 30 parts by weight of starch
B/n (coated and stacked 10 veneers so that the fiber directions were parallel. Then, 50 sets of these veneers were assembled into one
It was pressed as a heap under conditions of 12 kg/ca for 2 hours and room temperature to bind L V L with a high moisture content. Then, insert those L V L into a boll press and press the press cycle as shown in the drawing for 15 minutes - 120°C - 15kg/c
A 17VL with a desired moisture content of 4% was produced by hot pressing under the conditions of 1.

[Brief explanation of the drawing]

The drawings do not show one embodiment of the invention, but a hot press cycle. , Patent applicant Danya Sangyo Co., Ltd. II゛・1, Ritsu...,'

Claims (1)

[Claims] 1. After cutting and shaping the veneer obtained by peeling raw wood into the required dimensions without forced drying, the plying joint is bonded using a hardening synthetic resin adhesive that can be bonded on a wet surface. After the laminate is bonded under pressure to form a laminate under a vortex, the laminate is heat-pressed to accelerate the curing of the adhesive and reduce the moisture content of the laminate to the equilibrium moisture content in the atmosphere. Features: A manufacturing method for veneer laminates. 2. Manufacture of a veneer laminate according to claim 1, in which veneers obtained by peeling raw wood 1'flJ are stacked as a set of odd-numbered veneers so that the fiber directions are perpendicular to each other to form a plywood structure. Method. 3. The method for manufacturing a veneer laminate according to claim 1, wherein a plurality of veneers obtained by peeling raw wood are stacked in a 1:a ratio so that the fiber directions are parallel to form an LVL structure.