JPS62136264A - Coating apparatus - Google Patents

Abstract

PURPOSE:To surely laminate front and back liners of a post-stage, by applying the coating agent with desired viscosity in a tank heated by a heater to core base paper before forming corrugation through a coating roll. CONSTITUTION:The coating agent 3 in a tank 30 heated by a first heater 34 to be held to a molten state is supplied to a first tank 1 by a pump 36 and the excessive coating agent goes over a partition 44 to flow in a second tank 46. Core base paper 10 is guided by a plurality of rolls and the coating agent 32 is applied to the side of a front liner laminating surface 10a by the rotation of the coating roll 50 partially immersed in the tank 42 and the coated base paper reaches a doctor 54. The core base paper 10 from which the excessive coating agent was scrapped off by the doctor 54 is guided to a single facer 20 to be corrugated under heating and the coating agent is lowered in its viscosity to be penetrated in the core base paper 10. After the molding of corrugation, an aqueous starch adhesive 27 is instantaneously applied to the apex of corrugation and a back liner 28 is laminated to the corrugated core base paper.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a coating device, and more particularly to a device for coating a moving corrugated board with a hot-melt coating agent.

2. Description of the Related Art Various apparatuses for applying hot-melt coating agents have been known for a long time, and an example of an apparatus for applying hot-melt coating agents to corrugated paperboard is a paperboard wax processing apparatus disclosed in Japanese Patent Publication No. 55-5389. A typical example is a corrugated paper manufacturing apparatus described in JP-A No. 57-64542.

Problems to be Solved by the Invention However, when a lipophilic hot-melt coating agent such as paraffin wax, petroleum resin, or polyethylene wax is used to coat corrugated core base paper, the subsequent process A major problem occurs in the liner bonding process.

In other words, since a water-based starch adhesive is used to attach the liner to the core, whether it is the front liner or the back liner, the coating agent repels the starch adhesive, which tends to result in poor bonding. There are drawbacks.

As a result of intensive research on coating equipment, the present inventor found that in the case of a water-repellent coating agent, the coating agent is applied to the surface of the center core on the side where the front liner is laminated, and then further applied between the corrugated rolls. It has been found that the bonding between the corrugated cardboard core and the front and back liners can be improved by reheating the corrugated cardboard core.

Accordingly, a first object of the present invention is to provide an apparatus for applying a hot-melt type coating agent to core base paper before step forming.

Another object of the present invention is to provide an apparatus capable of applying the above-mentioned coating agent evenly and in an appropriate amount.

Another object of the present invention is to provide a heating system that maintains a hot melt coating at an appropriate viscosity.

Yet another object of the present invention is to provide a system for circulating the coating agent.

The gist of the present invention that quickly achieves the above-mentioned objects is that, in a device that applies a hot-melt type coating agent to a moving corrugated board core, a tank for storing the molten coating agent and a tank for storing the molten coating agent are used. , a pump that sends out the molten coating agent in the tank, a first tank that retains the molten coating agent from the pump, and a molten coating agent in the first tank that is attached to the front liner of the core base paper. a coating roll that applies to the mating surface; a doctor that scrapes off excess coating agent that has been applied to the core base paper; a presser roll that is arranged between the doctor and the coating roll and is movable up and down; and the doctor The present invention is characterized by comprising a second tank for receiving the excess coating agent scraped off by the tank, and a partition for allowing the excess molten coating agent in the first tank to overflow into the second tank. It is a coating device.

Structure and operation of the invention FIGS. 1 and 2 are main part configuration diagrams showing an embodiment of the apparatus of the present invention.

In a corrugated board manufacturing machine, corrugated core base paper lO is fed out from a mill roll stand (not shown) and is passed through suction rolls 12 for tension control and first to fifth rollers.
It reaches the single facer 20 through the guide rolls 13° 14.15, 17.18 and the presser roll 16.

This single facer 20 mainly includes an upper roll 22,
It is composed of a lower roll 24 and a pressure roll 26, and each roll 22, 24°26 is normally heated to 160°C~
It is heated to 180°C. These upper and lower rolls 22
．． The core base paper 10 is changed into a corrugated core by being pressed and stepped between 24, and the back liner 28 is attached to the corrugated core using a water-based starch adhesive applied to the corrugated top of the corrugated core. They are combined to form a single-sided corrugated board 29 and reach a bridge (not shown).

On the other hand, the hot-melt type coating agent 32 stored in the tank 30 is heated by a first heater 34 placed inside or outside the tank 30, and for example, in the case of paraffin wax, it is heated to about 110°C. It is kept in a molten state. There are no particular limitations on this coating agent 32, but paraffin wax,
Heat-melting resins and waxes such as polyethylene wax, petroleum resin, and rosin can be used singly or in combination of two or more.

The coating agent 32 melted in the tank 30 is supplied to the first tank 42 of the vat 40 by a pump 36 serving as a transfer means, and the excess coating agent overflowing the first tank 42 exceeds the partition 44. and flows into the second tank 46.

A coating roll 50 is rotatably disposed in the first tank 42 with a portion thereof immersed therein.

The applicator roll 50 is driven by a motor (not shown) and rotates in the opposite direction (arrow B) or forward direction to the running direction (arrow A) of the core base paper 10, and each rotation speed is approximately It is controlled to have a directly proportional relationship. The contact pressure between the core raw paper IO and the coating roll 50 is not directly compressed by a pressure roll or the like, but is applied by a presser roll 16 arranged at a slight distance from the coater roll 50.
Since only 0 is lowered, it is quite low, so-called a kiss touch. In addition, the presser roll 16 is placed directly above the application roll 50, and the core base paper 10 is
Squeezing causes uneven coating and wrinkles, which is not good.

The presser roll 16 is used because there is a risk that the core base paper IO will stick to the application roll 50 when the corrugator is stopped.
Normally, the presser roll 16 is automatically controlled to be lowered only when the core base paper 10 is traveling.

Since the coating roll 50 is not equipped with a doctor, the coating amount mainly depends on the viscosity of the coating agent 32, and is small when the viscosity is low and large when the viscosity is high. To achieve proper coverage, the viscosity is controlled to about 20 to 100 cps (centivoise), preferably 20 to 50 cps. Since the coating agent 32 is of a hot melt type, the viscosity can be controlled by controlling the temperature of the coating agent 32. For example, in the case of paraffin wax, it is usually necessary to heat it to about 80° C. to 90° C. Note that the relationship between viscosity and temperature varies depending on the components and distribution of the coating agent 32, so the temperature is selected appropriately.

The coated core base paper IO reaches the doctor 54 via the presser roll I6. There is no particular limitation on the shape of this doctor 54, and a knife-type doctor, wire-wound rod-type doctor, etc. can be used. This doctor 54 is a core base paper I
The coating agent excessively attached to the O is scraped off and dropped into the second tank 46 below. This second tank 46 is
The coating agent overflowing from the tank 42 and the excess coating agent from the doctor 54 are collected and returned to the tank 30.

The bat 40 is heated by a second heater 48 to keep it warm. The second heater 48 is installed in the bat 4.
0 is also possible, but from the standpoint of thermal inertia, a more uniform temperature distribution can be obtained by heating from the outside of the bat 40.

Before reaching the single facer 20, the coating agent is still applied to the back liner bonding surface of the core paper 10 on the core base paper IO with the coating agent applied to the front liner bonding surface 10a in this way. It has not penetrated to tob. However, the core paper
Since O is heated at the same time as it is step-formed by the single facer 20, the coating agent is further heated, its viscosity decreases, and it penetrates into the inside of the core base paper 10. Immediately after step forming, a water-based starch adhesive 27 is applied to the top of the step of the core, and a front liner 28 is bonded thereto.

At this time, since the coating agent does not ooze out to the surface of the back liner bonding surface tob, complete adhesion can be achieved even with a water-based adhesive. Conversely, if the coating agent is applied from the back liner bonding surface 10b side, the single facer 2
Even if the coating agent penetrates into the core by heating at 0, a small amount of the coating agent still remains on the surface of the core, and the back liner cannot be laminated sufficiently with the single facer 20. The exact cause is unknown, but it is probably due to pressure roll 26.
This is probably because the time to be compressed between the lower roll 24 and the lower roll 24 is only a moment (for example, if the line contact width is 0.8 mm and the traveling speed is 150 m/min, the clamping time is 0.32 milliseconds). Guessed.

The single-sided corrugated cardboard 29 temporarily stored in the bridge is heated with a preheater in accordance with a conventional method, then a starch adhesive is applied to the top of the corrugated cardboard, and a front liner (not shown) is laminated with a double facer (not shown) to form double-sided corrugated cardboard. becomes. At this time, the corrugated cardboard runs while being compressed by the hot plate of the double facer and the campus belt, and at the same time is heated from the front liner side by the hot plate. (See, for example, Japanese Patent Publication No. 5B-13343 and Japanese Patent Publication No. 59-49194 for the conventional method for double-sided corrugated board).

The length of the hot plate varies depending on the model, but it usually has a length of about 5m to 15m, so sufficient heat is applied to the bonding area, and strong adhesion is achieved even on the side where the coating agent is applied, that is, the side where the front liner is bonded. I can do it.

FIG. 2 shows another embodiment of the device of the present invention, in which the bat 40 is composed of first to third tanks 42°46.43, and the second and third tanks 46°43 are connected to the first tank. They are arranged so as to sandwich the WI 42 between them. The molten coating agent 32 from the tank 30 is injected into the third tank 43 via the pump 36.

The coating agent stored in the third tank passes through the second partition 45 to the first tank.
The water flows into the tank 42. At this time, since the level lines of the second partition 45 are at the same height, the average flow along the axis of the application roll 50 (that is, the longitudinal direction of the second partition 45)
A coating agent is poured into the tank 42.

When the third tank 43 is provided, the flow of the coating agent in the first tank 42 becomes uniform, and even more uniform coating becomes possible.

"Noboru" J and orbit.

(b) As described above, in the apparatus of the present invention, since the coating agent is applied to the core base paper IO before corrugation, the coating agent is reheated by the upper and lower corrugation rolls 22 and 24, and is coated inside the core. It has the advantage of penetrating into

(b) Also, since it is first applied to the surface to which the front liner is to be bonded, there is no problem with the coating agent when bonding the back liner.

(c) The viscosity of the coating agent is adjusted to 34.4 by the first and second heaters.
Since the temperature can be easily controlled by raising the temperature at 8, the coating agent can be applied evenly and in an appropriate amount.

(Since a means for heating the coating roll is not particularly required, the structure is simple, there are few causes of failure, and maintenance is easy.

(n) The viscosity of the coating agent is adjusted by a heating system such as the first and second heaters 34 and 48, and the coating roll 5
Since the coating amount is controlled by 0, there is no need to add a doctor roll (also referred to as a metering roll) to the coating roll 50.

[Brief explanation of drawings]

The drawings illustrate embodiments of the apparatus of the present invention; FIG. 1 is a block diagram of main parts showing one embodiment, and FIG. 2 is a block diagram of main parts showing another embodiment. IO... Core base paper 10a... Front liner bonding surface 10b... Back liner bonding surface 16... Presser roll 30... Tank 32... Coating agent 36... Pump 40 ... Bat 42 ... First tank 44 ... Partition 46 ... Second tank 50 ... Application roll 54 ... Doctor Patent Applicant Kyokuto Fatty Acid Co., Ltd. 82 Plan 0 (to y)

Claims (1)

[Scope of Claims] A device for applying a hot-melt type coating agent to a moving corrugated board core base paper, comprising: (a) a tank for storing the molten coating agent; and (b) a molten coating agent in the tank. (c) a first tank for retaining the molten coating agent from the pump; and (d) applying the molten coating agent in the first tank to the front liner laminating surface of the core base paper. A coating roll for coating, (e) a doctor for scraping off excess coating agent applied to the core base paper, and (f) a presser roll disposed between the doctor and the coating roll and movable up and down. (g) a second tank for receiving the excess coating agent scraped off by the doctor; (f) allowing the excess molten coating agent in the first tank to overflow into the second tank. A coating device characterized by comprising a partition and.