JPH0450809B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a lightweight top plate,
Specifically, the present invention relates to a method for manufacturing a lightweight top plate for a table, desk, etc., whose core material is a synthetic resin foam having screw receiving pieces made of wood inside.

[Prior Art] Top plates for tables, desks, etc. that use synthetic resin foam as a core material are lightweight and preferred; Since it is necessary to directly fix it, a foam core material is not suitable and it is difficult to put it into practical use.

Therefore, the present applicant previously proposed a lightweight top plate in which screw receiving pieces made of wood were embedded in a core material of a synthetic resin foam (see Utility Model Application No. 154022/1983). According to this top plate, the legs can be fixed with wood screws, bolts, etc., and it is preferable as a practical and lightweight top plate. When manufacturing this lightweight top plate, a pair of upper and lower surface plates are usually installed parallel to each other with an interval between them, and a screw receiving piece made of wood is temporarily installed on the inside of one of the plates using adhesive or the like. After that, a method of injecting a foamable synthetic resin into the resin, foaming it, and curing it is considered.

However, in this manufacturing method, during foaming after injection of the synthetic resin, especially during secondary foaming, the foaming around the screw receiving piece becomes uneven.
There is a drawback that the surface plate is deformed. In short, the area where the screw receiver piece is buried has less foaming than other zones, and the adhesiveness between the foamed synthetic resin and the wood that is the screw receiver piece is good, so as a result, the screw receiver piece is buried. The surface of the top plate on the opposite side to which it was glued dented as if it had been sucked in, making it impossible to obtain a horizontal top plate. Even if this dent is slight, when used as a top plate, its commercial value will be significantly reduced.

[Problems to be solved by the invention and means for solving the problem] In view of the above-mentioned circumstances, the inventors of the present invention have investigated various ways to prevent dents in the top plate near the screw receiving pieces that occur when synthetic resin is foamed, and have found that it is possible to inject foamable synthetic resin. We have previously discovered that by providing a release layer on the adhesive surface and upper surface of the screw receiving piece, deformation of the top plate of the screw receiving piece during foaming can be prevented, and we have completed the present invention.

[Structure of the Invention] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. is a surface plate, 3 is a synthetic resin foam layer, 4 is a screw receiving piece,
5 indicates a peripheral end member.

In the present invention, a synthetic resin foam layer 3 is filled as a core material between a pair of upper and lower surface plates 1 and 2 provided in parallel with an interval, and the inner layer corresponding to the leg attachment part is made of wood. This is a lightweight top plate with embedded screw receiving pieces 4, which are usually of the type that attach the legs of tables, desks, etc. with wood screws or bolts.
Its thickness is, for example, about 20 to 40 m/m.

In this top board, the upper and lower surface plates 1 and 2 are usually made of plywood or a material made by laminating plywood and melamine decorative board with a thickness of 2.5 to 6 m/m. , 2 may not necessarily be the same. The screw receiving piece 4 is made of a wooden material such as a piece of wood or laminated plywood, and is made of a material that can be fixed with a screw or bolt. The size of the screw receiving piece 4 is such that it fits within the upper and lower surface plates and is large enough to sufficiently secure the legs. The screw receiving pieces 4 may be attached to either the upper or lower surface plates 1 or 2, but usually,
It is preferable to attach it to the lower surface plate 2. Also,
The screw receiving pieces 4 are installed at locations corresponding to the locations where the legs are attached, and are usually 4 to 8 locations.

As the synthetic resin foam filled between the upper and lower surface plates 1 and 2, a semi-rigid or rigid polyurethane resin is typically used. Taking the case of polyurethane resin as an example, the foam layer 3 is formed using a conventional method, for example, using a polyvalent isocyanate such as tolylene diisocyanate or diphenylmethane diisocyanate and a polyol such as polyester polyol or polyether polyol. ,
Further, a catalyst and a foaming agent are mixed, and this mixture is injected to form a urethane resin, and at the same time, it is foamed and cured. Examples of catalysts used in this case include tertiary catalysts such as triethylenediamine and dimethylethanolamine.
and organic metal salts such as tin octoate and dibutyltin laurate. Further, examples of the foaming agent include low-boiling halogenated hydrocarbons such as trichloromonochloromethane, water, and the like, and in this case, it is preferable to use, for example, a silicone-based foam stabilizer in combination. The foaming ratio of the resin in the synthetic resin foam layer 3 varies depending on its use, but is generally about 15 to 25 times.

In order to manufacture the above-mentioned top plate, first,
Usually, upper and lower surface plates 1 and 2 are provided in a frame-like molding frame, and, for example, a screw receiving piece 4 is temporarily installed at a predetermined location inside the lower surface plate 2 to form a top plate base.
At this time, it is usually preferable to temporarily install the screw receiving piece 4 using an adhesive.

Then, a foamable synthetic resin is injected into the interior of the top plate base formed in this way, and is foamed and hardened inside to obtain the desired lightweight top plate.In the present invention, this foamable synthetic resin is This is characterized in that a release layer 9 is provided on the upper surface of the screw receiving piece 4 prior to injection of the synthetic resin. That is, due to the releasability imparting treatment on the surface of the screw receiving piece 4, when the injected synthetic resin foams, the top plate 1 is not attracted and the top plate surface is not deformed. The reason for this is that even if the foaming of the upper synthetic resin near the screw receiving piece 4 is small, the resin and the surface of the screw receiving piece 4 do not adhere firmly, so the surface plate is not sucked inward. Note that the surface plates 1 and 2 are strongly adhered to the foam layer 3 by the adhesive force caused by the foaming of the injected resin, and become an integral body.

Examples of the mold release layer 9 provided here include kraft paper, metal foil, plastic film, mold release agent, etc. Among them, kraft paper is pasted in advance before cutting the screw receiving piece and mold release agent is used. It is preferable to use it in combination with not only the effectiveness but also the workability. Furthermore, as the mold release agent, those used for molding ordinary synthetic resins, such as silicone wax type, can be preferably used.

A foamable synthetic resin is injected into the top board base material, and after the synthetic resin is foamed and cured, the top board is removed from the molding frame according to a conventional procedure. Then, if necessary, a suitable peripheral member 5 made of wood or synthetic resin is provided on the peripheral edge thereof, thereby completing the product top plate.

When attaching the legs 8 to the lightweight top plate obtained by the present invention, for example, as shown in FIG. The legs 8 can be fixed by screwing the wood screws 7 into the screw receiving pieces 4 through the through holes provided in the holes.

[Effect] According to the present invention, a beautiful top plate with a flat surface can be manufactured by an extremely simple operation of pasting, for example, kraft paper on the surface of the screw receiving piece when injecting the foamable synthetic resin. can.

[Examples, etc.] Reference example: The upper part is made of lauan plywood with a thickness of 2.5m/m and a thickness of 1m/m.
A pair of upper and lower surface boards (180cm long x 60cm wide) with a composite board pasted with a 2.5m/m thick melamine decorative board and a lower part made of 2.5m/m thick lauan plywood are spaced 2cm apart to form a picture frame. At the same time, after fixing screw receiving pieces (length 8 cm x width 4 cm x height 1.5 cm) made of wood pieces to the four internal corners of the lower surface board with adhesive, add tolylene diisocyanate 92 to the inside of the molding frame. Part, polyester polyol
100 parts and a foaming mixture containing triethylenediamine as a catalyst and water as a blowing agent,
By leaving the mixture for 5 minutes, the polyurethane resin was formed, foamed, and cured. Approximately 24 hours later, the manufactured lightweight top plate was removed from the molded frame and the condition of the top plate surface was observed. At all four locations near the surface of the upper surface plate where the screw receiver pieces were glued.
It was slightly deformed.

Example In the method of the reference example, kraft paper with an adhesive on one side was pasted on the top surface of all four screw receiving pieces, and a lightweight top plate was manufactured in exactly the same manner as in the example. As a result, a beautiful top plate with a flat surface over the entire surface was obtained. In addition, in this method, a lightweight top plate was manufactured in the same manner by attaching aluminum foil or polypropylene film instead of kraft paper, or applying a silicone-based wax type release agent to the top surface of the screw receiving piece. Similarly, a good top plate was obtained which was flat and had no dents.

[Brief explanation of drawings]

Fig. 1 is a partial perspective view showing an example of the top plate manufactured by the present invention as a partial cross-sectional view, and Fig. 2 is a partial cross-sectional view showing an example of the case where legs are attached to the top plate of Fig. 1. 1 and 2 are surface plates,
3 is a synthetic resin foam layer, 4 is a screw receiving piece, and 9 is a release layer.

Claims (1)

[Scope of Claims] 1. A foamed synthetic resin is placed inside a top plate base formed by temporarily installing a screw receiving piece made of wood on the inside of one of a pair of upper and lower surface plates arranged in parallel at intervals. A method for producing a lightweight top plate using a synthetic resin foam as a core material by injecting, foaming, and curing the lightweight top plate, characterized in that a release layer is provided on the upper surface of the screw receiving piece. . 2. The manufacturing method according to claim 1, wherein the release layer is kraft paper. 3. The manufacturing method according to claim 1, wherein the release layer is a plastic film. 4. The manufacturing method according to claim 1, wherein the release layer is a metal foil. 5. The manufacturing method according to claim 1, wherein the mold release layer is a waxy mold release agent. 6. The manufacturing method according to claim 1, wherein the synthetic resin foam is a semi-rigid or rigid polyurethane resin.