JP2000093880A - Application of hot-melt adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply the thin film of a hot-melt adhesive excellent in makeup property by spraying a molten hot-melt adhesive on the surface of a heated roller and transferring the adhesive on the roller surface to the surface of a material to be coated. SOLUTION: When a hot-melt adhesive, or the like, are applied on a wood, or the like, in mist coating, or the like, the original sheet of a skin material 1 is successively delivered, guided by a guide roller 13 and supplied between a roller 8 and an impression-cylinder roller 10. Meanwhile, the hot-melt adhesive sent from an adhesive feeder 2 through a pipeline 4 under pressure is jetted from the nozzle of a slot spray device 3 by the pressure air supplied from its source 5 through a solenoid valve 6 and applied on the surface of the roller 8 heated by a heater 9. The adhesive applied on the roller 8 surface is transferred on the skin material 1, the skin material 1 is stuck on a substrate 11 moving on the roller 12 of a conveyor, and a product is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying a hot-melt adhesive, and more particularly to a method for producing a hot-melt adhesive in a production process such as a decorative sticking process to wood and a transfer foil bonding process.
(Reactive polyurethane) The present invention relates to a method of applying a hot melt adhesive or the like in an extremely thin film.

[0002]

2. Description of the Related Art It is widely used in the industry to bond laminated members, such as films, having different functions with a hot melt adhesive therebetween to produce a laminated material.
For example, when producing decorative laminated wood as a building material, a skin material and a core material having a decorative pattern printed on the film surface in advance, such as a laminated material, MDF (Medium Densi).
There is known a method of producing a decorative laminated material by laminating an aluminum material or the like with a hot melt adhesive interposed therebetween.

As a conventional example, a typical example of a method of applying a hot melt adhesive in a production process of a decorative laminated wood will be described with reference to FIG. FIG. 2A shows a method for applying a hot melt adhesive by a coating die apparatus, and FIG. 2B shows a method for spray applying a hot melt adhesive using a slot spray apparatus.

First, in a method of applying a hot melt adhesive by a coating die apparatus shown in FIG.
Reference numeral 1 denotes a raw material of a film-like skin material on which a decorative pattern is printed in advance, reference numeral 22 denotes a hot melt adhesive supply device, and reference numeral 33 denotes a coating die device. As the coating die device 33, for example, JP-A-62-14
An apparatus known in Japanese Patent No. 4777 is used. The adhesive supply device 22 and the coating die device 33 are connected by a conduit 24 such as a hose. Reference numeral 31 denotes a base material such as wood serving as a core material. The base material 31 moves on a conveyor roll 32 in the direction of an arrow. 28 and 29 are guide rolls of the skin material 21, and 30 is a press roll.

Next, the operation will be described. The raw material of the skin material 21 is successively sent out, and the guide roll 29 and the press roll 3
When the temperature is between 0, the hot melt adhesive fed from the adhesive supply device 22 through the pipe 24 is extruded from the coating die device 33 and applied to the bonding surface of the skin material 21. Then, the skin material 21 to which the adhesive has been applied comes into contact with the base material 31 moving on the roll 32 of the conveyor, and is adhered to the base material 31 by the pressing force of the pressing roll 30 to form a product.

Next, a method for spray-coating a hot-melt adhesive using the slot sprayer shown in FIG. 2B will be described. Reference numeral 21 denotes a raw material of a film-like skin material having a decorative pattern printed on the surface in advance. Reference numeral 22 denotes a hot melt adhesive supply device, and reference numeral 23 denotes a slot spray device. As the slot spray device 23, for example, a device known in JP-A-6-170308 is used. Adhesive supply device 22 and slot spray device 2
3 is connected by a conduit 24 such as a hose. Reference numeral 25 denotes a pressure air source, which is connected to the slot spray device 23 via a conduit 27 via an electromagnetic valve 26. Reference numeral 31 denotes a base material such as wood serving as a core material.
2 move on the top in the direction of the arrow. 28 and 29 are skin materials 21
And 30 denotes a press roll.

Next, the operation will be described. When the raw material of the skin material 21 is sequentially sent out and comes between the guide rolls 28 and 29, the hot melt is pressure-fed from the adhesive supply device 22 through the pipe 24. The adhesive and the pressurized air supplied from the pressurized air source 25 via the electromagnetic valve 26 form a fibrous form from the nozzle of the slot spray device 23 and eject it onto the adhesive surface of the skin material 21 in a non-contact state. You. Then, the skin material 21 to which the hot melt adhesive is applied comes into contact with the base material 31 moving on the roll 32 of the conveyor, and is adhered to the base material 31 by the pressing force of the pressing roll 30 to be a product.

[0008]

The above-mentioned prior art has the following problems. That is, in the method of applying the hot melt adhesive by the coating die device shown in FIG. 2A, the applied thickness of the adhesive is inevitably increased. In particular, PUR (reactive polyurethane) hot melt adhesives are used in the range of 120 to 13
It is used in a heated and melted state at about 0 ° C.
Since it is relatively high at 00 to 30,000 cps, the coating thickness is about 30 μm in the current coating die apparatus. From the viewpoint of cosmetics and reduction of adhesive consumption, more thin film coating is required.

In the method for applying a hot melt adhesive by a slot spray device shown in FIG.
Although it can be applied in a relatively thin film form, the application method is fibrous, so if you look at the applied surface extremely finely, for example, if you look at it in a microscopic view, the applied surface of the adhesive will be uneven. Therefore, the unevenness appears on the surface of the skin material after the skin material is bonded, and a satisfactory quality has not been obtained particularly in a product requiring aesthetics. This phenomenon is particularly apparent when a PUR hot melt adhesive is used, and becomes more conspicuous as the thickness of the skin material decreases.

Under these circumstances, the present inventors have found a method of applying a hot-melt adhesive that is thin and yet has excellent aesthetics, which has been impossible with the improvement of the method of applying the adhesive. It is a thing. That is, an object of the present invention is to provide a method for applying a hot melt adhesive which is thin and excellent in cosmetics. Another object of the present invention is to provide a method for applying a hot melt adhesive, which is most suitable for thin film application of a PUR hot melt adhesive.

[0011]

In order to solve the above-mentioned problems, the present invention adopts the following method. That is,
First, a melt of a hot melt adhesive is spray-coated on the heated roll surface, and then the hot melt adhesive applied on the roll surface is transferred and applied to the surface of the object to be coated. Was applied. Further, in the method for applying a hot-melt adhesive described above, a method for applying a hot-melt adhesive using a PUR hot-melt adhesive as the hot-melt adhesive is employed.

[0012]

Next, an embodiment of the present invention will be described. In the present invention, first, a hot melt adhesive melt is spray-coated on the heated roll surface, so that the molten hot melt adhesive is present on the roll surface while maintaining high fluidity. Therefore, the coating surface having irregularities and undulations indicated by the fibrous coating state just after the coating is smoothed due to the fluidity. This smoothing phenomenon is called leveling in the art. Then, it is sufficiently smoothed on the heated roll surface, that is, is leveled, and is then transferred and applied to an object to be coated (skin material). After that, it is bonded to the adherend (substrate).

[0013] As a thin film coating method, compared with the extrusion coating method using a coating die apparatus described in the prior art,
The spray application method is much better. Moreover, according to the method of the present invention, the adhesive is smoothed on the surface of the heating roll and then applied to the object to be coated (skin material). As a result, the product after lamination has excellent cosmetic quality. And, compared with the extrusion coating method using the coating die device, there is obtained an advantage that the consumption of the adhesive can be reduced. Further, even in the application of a PUR hot melt adhesive having a relatively high viscosity, a thin film can be applied, so that the bonded product is excellent in cosmetics.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for applying a hot melt adhesive according to the present invention will be specifically described below with reference to the drawings. That is, FIG. 1 is a diagram showing an embodiment of a method for applying a hot melt adhesive to which the present invention is applied. In the figure, reference numeral 1 denotes a raw material of a film-like skin material on which a decorative pattern is printed in advance, 2 denotes a hot melt adhesive supply device, 3 denotes a slot spray device, and 3 denotes a slot spray device.
A known type was used in JP-A-6-170308. The adhesive supply device 2 and the slot spray device 3 are connected by a pipe 4 such as a hose. Reference numeral 5 denotes a pressure air source, and the pressure air source 5 is connected to the slot spray device 3 by a pipe 7 via an electromagnetic valve 6.

Reference numeral 8 denotes a roll, and the roll 8 used in this embodiment has a surface formed of heat-resistant silicone rubber. Reference numeral 9 denotes a half-moon-shaped heating device that covers the surface of the roll 8, and an infrared irradiation device is used as the heating device 9 in this embodiment. Reference numeral 10 denotes an impression cylinder roll, 11 denotes a base material such as wood, and the base material 11 moves on a conveyor roll 12 in the direction of an arrow. Reference numeral 13 denotes a guide roll for guiding the skin material 1.

Next, the operation will be described. The raw material of the skin material 1 is sequentially sent out and guided by the guide rolls 13.
It is supplied between the roll 8 and the impression cylinder roll 10. The hot melt adhesive pressure-fed from the adhesive supply device 2 to the slot spray device 3 via the conduit 4 is applied to the slot spray device by the action of pressure air supplied from the pressure air source 5 via the solenoid valve 6. The fiber 3 is jetted out of the nozzle of the device 3 and applied to the surface of the roll 8 sufficiently heated by the heating device 9.

The hot melt adhesive applied to the surface of the roll 8 is sufficiently smoothed until it comes into contact with the skin material 1 supplied between the roll 8 and the impression roll 10, that is, the leveling proceeds and complete The surface of the skin material 1 is formed as a film surface having a uniform thickness, and is transferred and applied to the skin material 1. The skin material 1 to which the hot melt adhesive has been applied meets a base material 11 such as wood moving on a conveyor roll 12 and is bonded to the base material 11 by the pressing force of the impression cylinder roll 10 to be a product. .

In the present embodiment, the surface of the roll 8 made of heat-resistant silicon rubber is irradiated with infrared rays for 120-120.
A test was conducted in which the skin material 1 on which a decorative pattern was printed in advance and wood as a core material were bonded using a PUR hot melt adhesive while heating at 150 ° C. A stable smooth coating was obtained with an adhesive coating thickness of 10 μm or less, and an extremely excellent appearance after bonding was obtained.

Although the hot melt adhesive is applied to the skin material 1 in the embodiment, it may be applied to the base material 11 side. Furthermore, although infrared irradiation was used as a heating means for the roll, the invention is not limited to this. For example, a method of blowing hot air or a method of circulating a heating medium inside the roll may be used.

[0020]

As described above, according to the present invention, there is provided a method for applying a hot-melt adhesive, which was impossible in the past, is a thin film, has excellent cosmetic properties, and further reduces the consumption of the adhesive. can do.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for applying a hot melt adhesive according to the present invention.

FIG. 2 is a diagram illustrating a conventional method of applying a hot melt adhesive.

[Explanation of symbols]

1 ... skin material, 3 ... slot spray device, 8 ... roll,
9: heating device, 10: impression cylinder roll, 11: base material.

Claims (2)

[Claims] 1. A hot melt adhesive is first spray-coated on a heated roll surface, and then the hot-melt adhesive applied on the roll surface is transferred and applied to the surface of the object to be coated. A method for applying a hot melt adhesive. 2. The method for applying a hot melt adhesive according to claim 1, wherein the hot melt adhesive is a PUR hot melt adhesive.