JPS6155444B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is a raw veneer in which the side edges of a small width raw veneer cut to a certain width are sequentially butted together so that the whole becomes a band shape, and these are connected in a webbing shape with threads. This invention relates to an improvement in the method of horizontally splicing boards.

Conventionally, as a method for horizontally joining green veneers cut to size, a method of gluing threads to green veneers arranged in a band shape with a urethane resin adhesive and joining the green veneers together is disclosed in JP-A-51-151312. It has already been proposed in public notices, etc.

However, when the urethane resin adhesive is cured by humidification, it takes a long time to achieve the desired adhesive strength, and therefore, simply bonding the threads to the surface of the veneer with the urethane resin adhesive will not allow the veneers to bond together. Since it is impossible to join the veneers together, and therefore it is impossible to move the veneers and join them horizontally continuously, we added a cut groove to the veneer, and applied the above thread and urethane resin adhesive to the cut groove. The first veneer bonding force is exerted by the physical adhesive force of the thread being inserted into the cut groove, creating a temporary temporary bonding state, and further bonding the temporarily bonded veneers. It was necessary to hold it in a stationary state and perform a curing process to harden the adhesive during that time.

Therefore, a device is required to cut grooves on the surface of the veneer, making the entire device expensive, and the fibers of the veneer, which are most important for the strength of the veneer, are cut in at least four locations, resulting in a significant decrease in strength. In addition, it required a large factory because it required space and time for curing, and had the disadvantage of low efficiency.

Although the present invention uses a urethane resin composition as an adhesive to join raw veneers together, it can be quickly and completely bonded, and there is no need to add grooves to the veneer, and the veneer itself 100% strength of
The purpose is to provide a method for horizontally joining green veneers that can be made into durable plywood by utilizing water-soluble veneers. After adding a curing agent and sequentially pulling out the dried threads, adding water to dissolve the curing agent, adding an adhesive made of a urethane resin composition between the threads and the raw veneer, and It is characterized by being bonded by applying pressure.

The present invention will now be described in more detail with reference to Examples. The fibers used are preferably heat-resistant fibers, such as Corderan and Jiyunron (both trade names) glass fibers, and these fibers are tied together or made into very thin fibers. A plurality of twisted threads are arranged together and a suitable molding adhesive (not for bonding the threads to a veneer) is added to form a tape or other suitable shape. Apply a water-soluble hardening agent such as acid and let it dry, or
or a water-soluble adhesive such as polyvinyl alcohol (not for bonding yarn to veneer)
A mixed solution of the above curing agent and the above-mentioned curing agent is applied substantially uniformly, and the dried yarn is wound onto a bobbin. This process is preferably carried out in an adhesive yarn manufacturing factory separate from the veneer factory.

Then, when the raw veneer is horizontally spliced, a small width of the raw veneer, which has been cut to a certain width in advance, is conveyed by a conveyor in a direction perpendicular to the fiber direction, and the side edges of the front and rear raw veneers are cut. On the other hand, the thread with a hardening agent wound on the bobbin mentioned above is passed through water while being sequentially pulled out, or when water is added by spraying steam or water, the surface of the thread is coated. The attached hardening agent dissolves, and in the case of coating mixed with polyvinyl alcohol, the hardening agent dissolves together with the polyvinyl alcohol.

In this curing agent dissolving step, the threads may be brought into pressure contact with the green veneer being transported and dissolved by the moisture contained in the green veneer itself.

A plurality of tanks containing the urethane resin composition are placed above the green veneer that is being transported in the form of a belt, and each tank is connected to the fibers on the band of raw veneer through a liquid guide tube. A urethane resin composition is connected to a nozzle or a coating roller facing at an appropriate interval in the direction, and the urethane resin composition is applied narrowly and continuously to the upper surface of the raw veneer, and this urethane resin composition is applied. When the hydrated yarn is guided and pressed into contact with the green veneer by heating or the like, the urethane resin composition rapidly reacts with the curing agent and hardens, and the yarn is bonded to the green veneer.

Next, to explain another bonding process, the yarn is pulled out from the bobbin, and water is added to the green veneer in the same manner as in the previous example while the yarn is in contact with or separated from the green veneer, and the urethane resin composition is The hydrated yarn is brought into pressure contact with the veneer by a shoe equipped with a heating means and the nozzle is attached between the yarn and the veneer, and then the urethane resin is applied directly above or from the side of the yarn. When the composition is ejected, the urethane resin composition rapidly reacts with the curing agent to be cured and bonded.

Note that a urethane resin composition may be added to the hydrated yarn and then pressed onto a strip-shaped veneer.

The green veneer thus bonded into a slat-like shape is cut into pieces with a fixed-length critter at the end of the conveyor, for example, a chain conveyor, in the bonding process, and then dried in a dryer.

As described above, when the side end surfaces of small width green veneers are brought together and connected into a band shape, the present invention adds a water-soluble hardening agent and sequentially pulls out the dried threads while adding water to the hardening agent. After melting, an adhesive made of a urethane resin composition is added between the threads and the green veneer, and they are bonded together under pressure. Using the urethane resin composition, it is possible to reliably bond and join within a short time, and there is no need to make cuts in the direction perpendicular to the fiber direction for temporary adhesion, that is, cuts to cut the fibers. The strength of the veneer is not reduced in the slightest, and the thick plate is stronger than the base.
It is also possible to bond and connect thin plates that could not be joined using conventional methods.

Furthermore, since a hardening agent is added to the yarn in advance,
At veneer manufacturing plants, all that is required is the addition of water to dissolve the hardening agent and the addition of a urethane resin composition.
At the veneer manufacturing factory, troublesome management work such as controlling the concentration and amount of hardening agent added to each individual piece can be omitted, making it possible to easily produce horizontally spliced veneers of stable quality even if one does not have advanced technology. Obtainable.

Moreover, even if the yarn breaks, it is only necessary to pull out the yarn and supply it to the crimping means, and the work efficiency can be significantly improved.

Claims (1)

[Claims] 1. When joining the side edges of small width green veneers together to form a band, add a water-soluble hardener and draw out the dried threads one by one while adding water to dissolve the hardening agent. A method for side-seaming green veneers, characterized in that an adhesive made of a urethane resin composition is applied between the threads and the green veneers, and the two are bonded together under pressure.