JPS62271724A - Melt painting method - Google Patents

Abstract

PURPOSE:To perform melt painting for a long period of time inexpensively and simply in a state that there is no change in quality of resin, by a method wherein a powder material and/or a grain material is fused or fluidized in order between intermeshing screws, a molten or fluidized thing is stretched into a sheetlike state between painting hot rolls and applied to the surface of a base by the painting roll. CONSTITUTION:Rolls supplying a powder and/or grain material into an accumulation part 8a of intermeshing screws 6a, 7a and an accumulation part 8b of intermeshing screws 6b, 7b and constituting the intermeshing screws 6a, 7a perform heterodirectional rotations in the direction of arrows. With this construction, the powder and/or grain material is heated, melted and turned into a liquid melt while being moved toward the central part of the rolls 4, 5 gradually. The powder and/or grain material melted through a heating action is shifted to painting hot roll parts 9, 10, which has been provided on the central part of the rolls 4, 5 and possess smooth surface, and turned into a sheetlike molten or liquidized thing suitable for the painting. The obtained sheetlike molten or fluidized thin 11 is applied continuously to the surface of a base 12 which is being carried by a supporting roll 13 provided close by the lower part of the painting roll.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] This invention involves melt-coating powder and/or granules that are solid at room temperature and have heat-melting or thermoplastic properties onto a substrate. A melt-coating method for melt-coating protective film-forming agents, pressure-sensitive adhesives, adhesives, and other resinous substances onto base materials.

In particular, the present invention relates to a novel coating method that can be widely applied to plate-like or sheet-like substrates of uniform thickness, and can be widely used in fields such as two-surface coating and lamination.

[Conventional technology]

Coating a resin that has been molten or fluidized (plasticized) by heat onto a base material using a heated roll has been widely practiced, especially in the field where melt adhesives are used. A device that combines an adhesive melting tank and a wheel or transfer roll has been widely used and is widely used for adhesives, laminations, etc.

We also have equipment such as fountain coaters and coating guns that combine slit nozzles and melting tanks.

Coating using an extruder is also conventionally known.

Among these methods, the method using a hot roll is the simplest method that allows direct transfer of a molten or fluid material onto a substrate, and is capable of coating a large area at low cost.

On the other hand, as shown in JP-A-59-177159, a hot-melt adhesive in the form of powder is supplied to an adhesive pool partitioned by a pair of heating rolls and a weir plate, and the adhesive is heated and melted. A melt coating method has also been proposed in which the coating material is formed into a sheet between the rolls and transferred onto the surface of the material to be coated.

[Problem that the invention seeks to solve]

In the above-mentioned known methods, when using a melting tank, it is difficult to avoid deterioration and discoloration of the resin component due to long-term heating due to the formation of wet liquid areas.

In particular, there have been problems with the application of resins that have properties such as thermal decomposition and thermosetting properties and poor heat stability.

In addition, the method using an extruder, which has the characteristic of being able to melt or fluidize powder and/or granules in a short time, requires a large area of equipment and is expensive, so it cannot be used in all cases. That wasn't necessarily the case.

Furthermore, in the melt coating method disclosed in JP-A-59-177159, the melted state of the resin adhering to the coating roll is uneven, unmelted powder and/or granules are mixed, and Because the ratio is unstable, the coated surface obtained is not smooth, and the thickness of the coated film varies significantly.In the case of particles with a large particle size, the particles tend to remain unmelted, increasing the coating speed. The drawback was that it could not be done.

At present, no technology has been available for melt-coating a hot-melt or thermoplastic resin at low cost and easily for a long period of time without alterations such as thermal deterioration or thermosetting.

[Means for solving problems]

In view of the current situation, this invention is the result of numerous studies on a melt coating method using a hot roll method that does not use a melting tank method, with the aim of providing a method that enables inexpensive, simple, and stable coating. When melt-coating the obtained powder and/or granules, which are solid at room temperature and have heat-melting or thermoplastic properties, on a substrate, the following steps (a) to (C) are sequentially carried out. It is characterized by the fact that it is carried out.

(a) A step of transporting and supplying the powder and/or granules between a pair of meshing screws each equipped with a temperature-adjustable heating means.

(b) The supplied powder and/or granules are sequentially melted or fluidized between the meshing screws, and the melted or fluidized powders and/or granules are connected coaxially with the meshing screws. A step of feeding between two coating heating rolls equipped with temperature-adjustable heating means.

(C) The molten or fluid obtained in the above step is spread into a sheet between the two coating heat rolls, and the base material is conveyed close to one of the coating heat rolls. The process of applying it to the surface.

In the method of this invention, what is the powder or/and granule that is solid at room temperature and has heat-melting or thermoplastic properties?

- a resin that is solid near room temperature (about 25°C) and becomes molten or fluid at a predetermined heating temperature;
Powder and/or granule composed of other materials (hereinafter referred to as
This powder and/or granule that is solid at room temperature and has heat-melting or thermoplastic properties is simply referred to as powder or granule. The particles of the granular material preferably have a maximum diameter of 20111 or less,
In this case, the particle size refers to the particle size after dispersion when the particles are loosely aggregated.

As the means for transporting and supplying the powder or granular material in the step (a), there is used a device that is suitable for the characteristics of the powder or granular material and the amount of transportation, and is equipped with a function that enables good constant M transportation.

Devices for such transportation and supply include, for example, a reciprocating feeder using a plunger, etc., a vibrating feeder using an electromagnetic vibrator, an endless belt feeder, a table feeder using a rotary table, and a complete screw feeder.

Pneumatic feeder, bucket 7) type feeder.

There are roll feeders using mensch rolls, rotary feeders, etc.

Furthermore, the pair of meshing screws in step (a) are formed by carving one or more grooves on the surface of the metal roll, and meshing the grooves by rotating them in different directions. This has the function of sequentially transporting the powder and granules supplied from one side of the meshing screw to the other side, and gradually melting or fluidizing the powder and granules during this time.

The granular material receiver has heating means for controlling the temperature from the time it is placed until it is melted or fluidized.

Specifically, this temperature-adjustable heating means uses steam from the inside or outside of the meshing screw.

The temperature is controlled by heating or cooling with a heat medium such as water, hot water, or circulating oil, or by heating with electricity such as an electric or electromagnetic heater.

Note that the temperature adjustment by the heating means may be performed in appropriate steps in the length direction of the meshing screw, and may be adjusted for each zone.

The pair of meshing screws may have different diameters, or the pitches of one or more grooves formed on the surface may be changed according to the respective diameters.

The heating rolls for coating in steps (b) and (C) consist of a set of two heating rolls, one of which is a coating roll and the other of which is a doctor roll, etc., and the distance between these rolls can be finely adjusted to coat the substrate. The film thickness of the resin is set to a predetermined thickness when coating the resin.

The molten or fluid powder formed into a sheet by this heated coating roll is applied onto a base material that is conveyed close to one of the coating rolls in step (C). .

The material of the pair of coating heat rolls may be any heat-resistant material, but heat-resistant resin, rubber, etc. are preferable for the coating rolls as the two surface materials for film-forming transfer of molten or fluid materials. The doctor rolls are preferably made of metal, ceramics, or heat-resistant resin rubber, and it is preferable that the two heating rolls for coating have mutually different peripheral speeds of rotation.

Each of the steps (a) to (c) can be carried out continuously using a single coating device that has functions suitable for each step, minimizing the installation area.

In other words, for a coating heat roll consisting of a set of two rolls,
The pair of meshing screws are configured to be coaxially connected to their ends, preferably both ends, and rotated synchronously, and the powder supply device is coupled to the meshing screws. By doing so, the powder and granules from the powder and granule supply device are supplied to the meshing screw, and the powder and granules are gradually turned into a molten state or fluidized state toward the coating heat roll coaxially connected with the meshing screw, and then the coating is applied. It is fed to an industrial heat roll to be spread into a sheet and then applied onto a substrate.

[For production]

Specifically, the method of the present invention includes pumps 2a and 2b installed at both ends of the coating W1 as shown in the attached drawings.
The powder and granular material A inside is fed to the powder and granular material feeder 3a.

3b, a set of two meshing screws 6a, 6b and 7a equipped with temperature-adjustable heating means at both ends;
7b is supplied to the ends of reservoirs 8a and 8b by meshing,
The meshing screw 6a.

By rotating 6b and 7a, 7b.

The supplied powder and granular material is connected to the meshing screw 6a.

Coating heat roll 9 coaxially connected to 6b, 7a, 7b
, 10 while being sequentially melted or fluidized to form a melt or fluid B.

In this case, if a method using meshing screws is adopted for transporting, heating and melting or fluidizing the powder or granular material A, the self-cleaning action of the meshing screws will cause almost no wetting of the melted or fluid material B, and the supplied powder or granule will Since A can be constantly moved and transported sequentially in the direction of the coating hot roll 9 and 10 without delay,
Heat denaturation of the resin can be kept to a minimum.

The molten or fluidized material B melted or fluidized by the above method is transferred to the coating hot roll consisting of the coating roll 9 and the doctor roll 10 to form a sheet 611 and onto the base material 12. Coating roll 9. The screw 5a engages the doctor roll 10 together.
, 5b and 7a, 7b, by providing a temperature-adjustable heating means, the temperature of the molten or fluid B can be maintained at a predetermined temperature and coating can be easily performed.

The molten or fluid material B of powder and granules supplied to a set of two heat rolls constituting the coating heat rolls 9 and 10 is passed through a meshing screw 6a composed of a set of two rolls in the preceding stage.
, 6b and ? a, 7b because it is continuously supplied in a molten or fluid state.

9. An unmelted or non-fluid solid material is transferred to a heating roll for coating.
It can be continuously and stably applied to the substrate 12 without adhering to the substrate 10.

Although the coating roll 9 and the doctor roll 10 are normally rotated in different directions, they can also be rotated in the same direction under specific conditions such as when the supply amount and viscosity of the melted or fluidized resin are low.

In this case, one meshing screw 5a, 5 on the supply side
b is the coating roll 9 and the other meshing screw? a,
7b is coaxially connected to the doctor roll 10, so the meshing screw and the coating roll or doctor roll always rotate in the same direction.

Coating to the base material 12 is carried out by supporting the base material 12 with a support roll 13 provided close to the coating roll 9, and applying the melted or fluidized material B to the coating roll 9 to form a film in the form of a sheet. It can be easily coated by conveying it in contact with.

〔Example〕

Hereinafter, an example of an apparatus for implementing the method of the present invention will be specifically described with reference to the drawings.

Coating device 1 which is an example for carrying out the method of this invention
As shown in FIG. 1, the meshing screw 6a is composed of a set of two screws equipped with a temperature-adjustable heating means;
? a, 6b, 7b, a set of two coating heat rolls 9.10 equipped with temperature-adjustable heating means coaxially connected to the meshing screws, and one of the coating heat rolls 9. It is comprised of a support roll 13 provided in parallel at a position close to the bottom, and hoppers 2a and 2b provided on one side of the meshing screw.

The pumpers 2a and 2b are arranged at the upper portions of both ends of the coating device 1, and screw-type powder feeders 3a and 3b are directly connected to the lower portions thereof, respectively.

a meshing screw 6a composed of a set of the two screws;
7'a, 6b, 7b, and the two coating heat rolls 9, 10 that are coaxially connected to this meshing screw are composed of a pair of rolls 4.5 with different diameters. .5 has screw-like grooves carved on the outer circumferential surface of each of its both ends, and engages with the screw portions 6a, 6b and 7a, 7.
It forms b.

That is, the meshing screw portions 6a and 7a and the meshing screw portions 6b and 7b are configured to mesh with each other, and the recesses formed at the upper portions of these mutually meshing portions are used to supply powder and granules and a molten material made by melting the same. Reservoir 8
a, 8b.

Further, in the center of the roll 4.5, coating hot roll parts 9 and 10 having smooth surfaces and having no screw-like grooves are formed.

That is, one roll 4 has a meshing screw 6a,
A coating roll 9 is integrally and coaxially formed in the center of one roll 6b, and a doctor roll 10 is integrally and coaxially formed in the center of the meshing screws 7a and 7b of the other roll 5.

Both ends of the roll 4.5 having such a structure, namely the interlocking screw parts 5a, 6b and 7a.

At the base end of 7b, there is a heating means 14a whose temperature can be adjusted.
14b, and a hose 15 for circulating the heating medium.

The temperature-adjustable heating means 14a, 14b.

Specifically, steam, water, hot water, and circulating oil are used as the heating medium for the meshing screws and rolls, and an electric or electromagnetic heater can also be used instead.

These heating means 14a, 14b, meshing screw parts 6a, 6b, 7a, 7b and coating heat roll part 9.1
0 has a structure that allows heating to a predetermined temperature in each zone provided at an appropriate step from receiving the powder to melting and coating, and naturally meshing screw parts 6a, 6b, 7a
, 7b, the coating heat roll parts 9, 10, etc., when the temperature thereof rises above a predetermined temperature, it is possible to lower the temperature by cooling them.

The melt coating apparatus 1 having such a configuration has a meshing screw 5a, as explained in the operation section.

By supplying the powder to the reservoirs 8a and 6b of 7a and the reservoir 8b of 7b, and rotating the rolls 4.5 constituting the meshing screw in different directions in the direction of the arrow, the powder gradually flows into the roll 4. While moving toward the center of the .5, it is heated and melted to become a liquid melt.

The granular material melted by the heating action is further transferred to roll 4.
Coating hot roll parts 9 and 10 with smooth surfaces provided in the center of 5
It becomes a sheet-like molten or fluid material suitable for coating.

The obtained sheet-like molten or fluid material 11 is conveyed to a base material 12 by a support roll 13 provided in parallel and close to the bottom of the coating roll 9, as shown in FIG.
Continuously applied to the surface of

〔Effect of the invention〕

The melt coating method of the present invention, which consists of the steps described above, can successfully and easily melt coat various types of synthetic resins, which have conventionally had problems in thermal stability, onto base materials. It has many advantages as described in the following.

■ The process time for melting and feeding powder and granular materials such as heat-melting resins is short, so deterioration due to heat is less likely to occur.

■ Since there is no wet part of the powder or granules during operation, heating and melting is performed evenly, and the resin etc. are not easily denatured by heat even during long hours of operation.

(2) Since the resin is directly and continuously supplied in a molten or fluid state to the hot roll for coating, it is possible to continuously perform clean and complete coating.

(2) Since the apparatus for carrying out the method of the present invention is handled in the process zone, it is easy to clean the apparatus after work, and there is no need to replace parts due to blockage of powder or granules.

Furthermore, since the melt coating method of the present invention has the above-mentioned advantages, it also has features such as being applicable to the uses described below.

■ Melt coating or lamination of resins whose viscosity decreases significantly due to thermal decomposition.

■ Melt coating or lamination of resins that are highly colored due to thermal denaturation.

■ Melt coating or lamination of reactive real-melt adhesives or adhesives.

■ Applying adhesive to the core cell edge when bonding the honeycomb core and surface material during the manufacture of honeycomb core sand inch structures.

[Brief explanation of drawings]

FIG. 1 is a simplified perspective view showing an example of a coating apparatus for carrying out the method of the present invention, and FIG. 2 is a sectional view taken along the line ■--■ in FIG. 1... Coating device 2a, 2b... Hopper 3a, 3b... Powder feeder 6a, 6b, 7a, 7b... Engaging screw 8a, 8b... Reservoir 9... Coating Doctor roll, 10...Doctor roll 11
...Sheet-like molten or fluid object 12...Base material, 13...Support rolls 14a, 14b
...Heating means

Claims (1)

[Claims] When melting or fluidizing powders and/or granules that are solid at room temperature and have heat-melting or thermoplastic properties on a substrate, each of the following (a) to (c) is applied. A melt coating method characterized by sequentially performing the steps. (a) A step of transporting and supplying the powder and/or granules between a pair of meshing screws each equipped with a temperature-adjustable heating means. (b) The supplied powder and/or granules are sequentially melted or fluidized between the meshing screws, and the melted or fluidized powders and/or granules are connected coaxially with the meshing screws. A step of feeding between two coating heating rolls equipped with temperature-adjustable heating means. (c) The melted or fluid obtained in the above step is spread into a sheet between the two coating hot rolls, and the base material is conveyed close to one of the coating hot rolls. The process of applying it to the surface.