JPS61259776A - Method and apparatus for spraying hot melt type adhesive - Google Patents

Abstract

PURPOSE:To perform stable spraying, in spraying a hot melt type adhesive from a spray nozzle in a molten state, by using compressed air heated to predetermined temp. CONSTITUTION:The hot melt type adhesive melted in a hot melt applicator 1 under heating is extruded by compressed air sent from piping 8 and supplied to a gun 4 through a hose 3. The adhesive in the gun 4 is supplied to a spray nozzle 2 by the pressure of compressed air introduced into the gun 4 through piping 9. Compressed air introduced into a circulation heater 7 from piping 5 and heated thereby passes through a flexible hose 6 to be introduced into the spray nozzle 2 in a state heated to predetermined temp. by the heater 12 on the way of said hose 6 and injected from the nozzle 2 along with the hot melt type adhesive held to a molten state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus capable of stably spraying a hot melt adhesive.

[Conventional technology] Hot-melt type bonding whose main component is thermoplastic resin
□The adhesive is sprayed onto the object to make it adhere.
Since no organic solvent is required in this process, it is suitable for preserving the working environment. however.

The method and conditions for stably spraying hot melt adhesives have not been fully elucidated, and conventionally it has been difficult to stably spray hot melt adhesives.

For example, Japanese Patent Publication No. Sho 56-5389 describes a method for producing heat insulating materials using hot-melt adhesive, but this method uses hot-melt adhesive to prevent fibers from scattering; There is no description of the method of spraying the hot-melt adhesive or the equipment, and Japanese Utility Model Application Publication No. 58-136332 describes a surface material bonded to a glass wool mat using hot-melt M adhesive. The device itself is not described.

[Problems to be Solved by the Invention] As described above, in the past, methods and devices for stably spraying hot melt adhesives have not been sufficiently developed. It was not possible to spray evenly. Further, the hot melt adhesive could not exhibit sufficient adhesiveness, and the adhesive strength of the adhesive layer tended to be low.

[Means for Solving the Problems] The hot melt adhesive spraying method of the present invention uses compressed air heated to a predetermined temperature when spraying the molten hot melt adhesive from a spray nozzle. This is what I did.

Further, the hot melt adhesive spray device of the present invention includes:
In an apparatus equipped with a means for heating and melting a hot melt adhesive, a means for supplying compressed air, and a spray nozzle into which molten hot melt resin and compressed air are introduced from both of these means, heating the compressed air to a predetermined temperature. It is designed to provide a means for doing so.

[Function] In the present invention, the molten hot melt adhesive is sprayed from a spray nozzle by compressed air heated to a predetermined temperature, so the hot melt W adhesive is maintained in a viscosity range suitable for spraying. It is possible to perform a stable spray.

Further, in the present invention, the viscosity of the hot melt adhesive in a state in which it is attached to an object can also be adjusted, and it is also possible to make the adhesive force sufficient.

The present invention will be described in more detail below with reference to embodiments shown in the drawings.

FIG. 1 is a structural diagram of a hot-melt adhesive spraying device according to an embodiment of the present invention. This device includes a hot melt applicator l as a means for heating and melting a hot melt adhesive, a spray nozzle 2 such as a two-fluid nozzle (consisting of a nozzle 2a and a block 2b), and a spray nozzle 2 to which a molten state is applied. a hose 3 and a gun 4 as means for supplying the hot melt adhesive; a pipe 5 connecting a compressed air source (not shown) and the spray nozzle 2 to supply compressed air to the spray nozzle 2; A flexible hose 6, a circulation heater 7 as compressed air heating means provided at a point a between the piping 5 and the flexible hose 6, and compressed air supplied to the hot melt applicator l and the gun 4 from a compressed air source (not shown). It is configured with piping 8 and 9 for.

In the figure, □.lO and 11 are pressure gauges installed in the middle of the pipe 8.9. Further, 6a is an air flow control valve. 'Also, the circulation heater 7
In addition, a heater 2 that generates heat when energized and an asbestos ribbon for heat insulation (not shown) are wound around the flexible hose 6.

In the hot-melt adhesive spraying device configured as described above, the hot-melt adhesive is heated and melted in the hot-melt applicator 1. '''1°1 press
The molten hot melt adhesive introduced into the gun 4, which is dispensed and supplied into the gun 4 via the hose 3, is heated by the pressure of the compressed air introduced into the gun 4 via the piping 9. is supplied to the spray nozzle 2 by. On the other hand, the compressed air introduced into the circulation heater 7 from the piping 5 and heated passes through the flexible hose 6, further heated by the heater 12 along the way, and introduced into the spray nozzle 2. Then, it is ejected from the spray nozzle 2 together with the molten hot-melt adhesive introduced from the gun 4 into the spray nozzle z. The spray nozzle 2 may be of any type, such as an internal mixing type that mixes air and adhesive in the nozzle and then sprays it out, or an external mixing type that scatters the discharged adhesive with an air flow. You can also use things.

The spray nozzle 2 is provided with a sensor (not shown) that detects the temperature of the heated compressed air introduced from the flexible hose 6, and the detected value of this sensor is the amount of heat generated by the heater 12. A controller for suppressing (
(not shown) and is configured to be able to adjust the temperature of compressed air introduced into the spray nozzle 2 to a predetermined value. (Of course, the degree of heating by the circulation heater 7 may be adjusted to i [. Air can be used to spray from the spray nozzle 2, so hot melt when spraying)! The viscosity of the adhesive can be adjusted to a desired value, making it possible to perform stable spraying. Furthermore, by selecting the compressed air temperature during spraying so that the viscosity of the hot-melt adhesive when it is attached to the object is a viscosity suitable for adhesion, the adhesive force of the adhesive is also sufficient. I can do it. Note that this adhesive strength can be made even higher by adjusting the composition of the hot-melt adhesive, for example, the blending ratio of the tackifying resin.

In the present invention, the hot-melt adhesive mainly contains atactic polypropylene (APP), ethylene vinyl acetate (EVA), or vinyl acetate, and a tackifying resin such as petroleum-based synthetic resin. Preferably, it is added. Asphalt can also be used.

In the case of a hot melt adhesive using APP resin as the main component and adding petroleum-based synthetic resin as a tackifying resin, it is preferable to use one having the following viscosity characteristics, for example.

140° C., 1800-2700 cps 150° C., 1300-2000 cps 160° C., 1000-1500 cps Suitable examples of such materials include those sold by Matsumura Sekiyu Co., Ltd. as Moresco Melt S-151.

In addition, in the case of a hot melt adhesive mainly composed of such an APP resin, an appropriate viscosity during spraying can be obtained by setting the temperature of the air introduced into the spray nozzle to 175° C. or higher. In addition, if the temperature of the hot melt adhesive exceeds 180°C, thermal decomposition of the APP resin will occur, and the generated carbide may adhere to spray nozzles and cause nozzle clogging, so APP resin is the main component. In the case of a hot-melt adhesive, the maximum heating temperature of the resin is preferably 180°C or lower.

Next, the results of a spray test conducted using the apparatus shown in FIG. 1 will be explained.

Hot melt applicator: Nordson (HMQ type) Gunni Nordson H20A Hose: Nordson block: Shinchu processed product nozzle: Spray System Japan ■Curation Heater 2 Universal Heater ■5ACH325,2,
5kw Hot melt adhesive: Pine wood petroleum S-151 ('%□Compressed air pressure crab 4~6kg/cm''''
Pressure crab of hot melt adhesive: 0.8 to 1.5 kg/ctn' When spraying was performed under these conditions, the following was observed.

■ Good spraying is possible when the temperature of the air introduced into the block is 175°C or higher.

■ If the surface temperature of the block is below 170°C, the spray pattern will be distorted.

■ If the block surface temperature is below 150°C, it will not be possible to spray well, but the amount of hot melt adhesive dispensed should be 2
When doubled, the spray pattern becomes better.

■ The best spray pattern can be obtained when the surface temperature of the block is approximately 175°C.

■ If the heating temperature of the hot melt adhesive exceeds 180°C during mixing in the spray nozzle, thermal decomposition within the resin will begin, and the resulting carbides will likely clog the nozzle.

[Effects] As described above, according to the present invention, hot-melt adhesives can be stably sprayed. Furthermore, the adhesive force of the sprayed hot melt adhesive can be made sufficient.

Therefore, according to the present invention, the use of organic solvents can be eliminated in various processes such as the process of bonding skin agents to inorganic fiber products, which conventionally used organic solvents, and the work environment can be improved. can play.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of an apparatus according to an embodiment of the present invention. l...Hot melt applicator, 2...Spray nozzle, 3...Hose, 4...Gun, 6...Flexible hose, 7...Circulation heater.

Claims (5)

[Claims] (1) When hot-melt adhesive is heated and melted, introduced into a spray nozzle, and sprayed from the nozzle toward an object using compressed air, compressed air heated to a predetermined temperature is used as the compressed air. A hot melt adhesive spraying method featuring: (2) The hot-melt adhesive spraying method according to claim 1, wherein the object is an inorganic fiber product such as a glass wool mat. (3) The method for spraying a hot melt adhesive according to claim 1 or 2, wherein the hot melt adhesive contains atactic polypropylene as a main component and also contains a tackifying resin. (4) The hot melt adhesive according to claim 3, wherein the temperature of the compressed air is 170°C or higher, and the temperature of the hot melt adhesive when mixed with the compressed air is 180°C or lower. Spray method. (5) A spray nozzle connected to a compressed air supply means, a means for heating and melting the hot melt adhesive, and a means for feeding the molten hot melt adhesive from the heating and melting means to the spray nozzle. and heating means for heating compressed air supplied to the spray nozzle to a predetermined temperature.