JPH0576419B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a single facer for manufacturing single-sided corrugated board, which is one unit of a corrugator, which is corrugated board manufacturing equipment.

(Prior Art) A conventional general single facer employs the structure shown in FIG. 3. In the figure, 1 is an upper roll, 2 is a lower roll, 3 is a hollow pressure roll, 4 is a glue roll, 5 is a doctor roll, 6 is a glue container, 7 is glue, 8 is core paper, and 8a is a wave-shaped 9 shows a liner, and 10 shows a single-sided corrugated cardboard.

First, the manufacturing process of single-sided corrugated board 10 using a single facer with the above configuration will be explained. The core paper 8 is supplied to the upper roll 1 side, is bitten by the interlocking part of the upper roll 1 and the lower roll 2, and is undulated. It is formed into a shape and becomes a corrugated core paper 8a. Next, the corrugated core paper 8a is transferred with the rotation of the lower roll 2, the glue 7 in the glue container 6 is scooped up by the glue roll 4, and the glue film is adjusted by the doctor roll 5. Gluing is applied to the top of the corrugated core paper 8a. At the same time, the liner 9 supplied to the pressure roll 3 side and the corrugated core paper 8a glued to the top of the corrugation join and adhere at the pressing portions of the lower corrugation roll 2 and pressure roll 3 to form a single-sided corrugated board 10.

In the conventional single facer having the above structure, the upper roll 1 is pressed against the lower roll 2, and the pressure roll 3 is pressed against the lower roll 2. The former is used to pressurize the corrugated core paper 8 to form tiers, and the latter is used to apply heat to rapidly raise the temperature of the commonly used liquid starch paste attached to the top of the tiers of the corrugated core paper 8a to gel it. The purpose is to press the heated pressure roll 3 with high pressure using the heated steam introduced into the hollow part 3a of the pressure roll 3 as a heat source to promote heating by heat conduction.

In addition, the lower roll 2, together with the upper roll 1, has tooth-shaped steps processed on the outer surface of the roll at equal pitches, while the pressure roll 3 has a smooth surface, so that each of the lower rolls 2 is The structure is such that the top of the step hits the surface of the pressure roll 3 at high cycles. That is, the main component of the upper roll 1, the lower roll 2, and the pressure roll 3 is the cycle of the number of teeth of the upper and lower rolls 1 and 2, that is, the number of revolutions of the corrugating rolls N x the number of teeth Z, and the vibration eigenvalue of the roll system vibrates with the number of teeth. When several cycles of NZ match, resonance occurs and the three rolls vibrate violently. During such resonance, especially the stepped portions of the pressure roll 3 and the lower roll 2 collide violently, so a large collision load is applied to the corrugated core paper 8a and the liner 9, which are sandwiched between the two rolls 2 and 3. Depending on the phase of the vibration, the linear pressure between the lower roll 2 and the pressure roll 3 may be insufficient, leading to insufficient adhesive strength and poor bonding.

Furthermore, the collision between the lower roll 2 and the pressure roll 3 generates a large amount of noise, which is an important problem for single facers.

Further, in the above conventional structure, glue is applied to the corrugated top part of the corrugated core paper 8a, and the glue is applied at a gelling temperature (usually 60° C. As a method of raising the temperature to a temperature close to 30°F (°C), indirect heat is provided by using the hollow part 3a of the pressure roll 3 as a heat source and heating the glue part by heat conduction and heat transfer via the flesh part of the pressure roll 3 and the liner 9. means are adopted. However, this method not only raises the temperature of the roll meat and paper that do not need to be heated, but also leads to a loss of thermal energy.Especially when the machine is operated at high speed, the supply of heat decreases, causing the glue to deteriorate. It becomes impossible to raise the temperature to the gelation temperature, resulting in poor adhesion. That is,
As long as the above-mentioned conventional structure was adopted, there was a limit to how high the speed could be increased.

(Problems to be Solved by the Invention) The present invention solves the vibration problems of the conventional single facer, such as noise and material paper breakage, and also solves the problems of the conventional single facer, such as noise and material paper breakage. This was proposed for the purpose of improving heating means, and from the viewpoint that the presence of pressure rolls is the fundamental cause of the vibration and thermal energy loss mentioned above, a new and efficient method was proposed that eliminated the pressure rolls. The aim is to provide a single facer that uses a heating and bonding method.

(Means for Solving the Problems) Therefore, the present invention comprises an upper roll and a lower roll that interlock with each other for corrugating the core paper, and a gluing device that applies glue to the top of the corrugation of the core paper after the corrugation. In a single facer, the liner is applied to a considerably wide desired circumferential surface of the lower roll through the corrugated core paper, and surface pressure is applied by an endless belt or a spray container for spraying static pressure gas. By providing a means for applying pressure, and arranging a grid electrode near the surface pressure applying portion of the lower roll and applying a high frequency voltage between adjacent electrodes,
The adhesive is dielectrically heated under uniform pressure to adhere the core paper and liner, and this is a means to solve the problem.

(Function) Since the single facer of the present invention has the above-mentioned configuration, first of all, we will talk about the means of pressure contact between the liner and the core paper. Since a substantially uniform pressure is applied, there is no external force that would cause rigid body vibration of the roll due to point high pressure caused by the pressure roll as in the conventional case.

Furthermore, several grid electrodes that cooperate with the pressure contact means are arranged close to the lower roll, and a high frequency voltage is applied between adjacent electrodes, that is, between the (+) pole and the (-) pole. Application of such a high frequency voltage generates an electric field between adjacent electrodes. This electric field enables dielectric heating.

In particular, the dielectric capacity of water in glue and paper is 20 to 30 times higher in water, so the electric field generated is concentrated in the glue part. In other words, the temperature of the paper hardly rises, and only the temperature of the glue portion rises rapidly, causing gelation.

In other words, with this method, for the target part to be heated,
Rather than the conventional heating method that utilizes heat conduction/transfer, it uses a method that induces internal self-heating.

(Examples) Hereinafter, the present invention will be described in detail based on Examples of the present invention. FIG. 1 is a schematic side sectional view of a single facer showing a first embodiment of the present invention.

In the figure, 1 is the upper roll, 2 is the lower roll, 4 is the glue roll, 5 is the doctor roll, 6 is the glue container, 7 is the glue, 8 is the core paper, and 8a is bitten by the upper and lower rolls 1 and 2. corrugated core paper formed into a corrugated shape, 9
1 is a liner, and 10 is a single-sided corrugated board formed by laminating a corrugated core paper 8a and a liner 9. The above is similar to the conventional portions shown in FIG. 3, which are denoted by the same reference numerals.

11 is the corrugated core paper 8a of the lower roll 2 and the liner 9
Rod-shaped grid electrodes 12 having a length approximately equal to the roll length of the lower roll 2 are arranged in the axial direction at appropriate intervals close to the circumferential surface over the bonding area of the electrodes. A spray container for supplying static pressure gas for pressurizing the liner 9,
The grid electrode 11 is disposed opposite to the side opposite to the lower roll. Reference numeral 13 denotes a guide roll for guiding the liner 9 between the lower roll 2 and the grid electrode 11.

When this device having such a configuration is operated, the core paper 8 is moved to the upper and lower rolls 1 and 2 as in the conventional case.
After being bitten into the corrugated core paper 8a and formed into the corrugated core paper 8a, the glue 7 is applied to the corrugated top part of the corrugated core paper 8a by the gluing roll 4, and the corrugated core paper 8a is bonded to the liner 9 that is fed separately. However, at this bonding part, the spray container 1
Since gas is discharged from behind the liner 9 toward the bonding section, this pressure causes the liner 9 to
The corrugated core paper 8a and the corrugated core paper 8a are firmly attached to each other through the glue applied to the top of the step.

Further, in the grid electrode 11 disposed close to the lower roll 2, for example, there is a gap between the adjacent electrodes.
Since a high frequency voltage of 30 to 300 MHz is applied, the glue placed in the electric field generated by this generates self-heating and rapidly heats up and becomes a gel.

In general, dielectric heating is performed by applying E.
It generates radiation proportional to ε・tanδ・f (ε: relative dielectric constant, tanδ: dielectric loss coefficient, f: frequency, E: electric field strength), of which ε・tanδ takes a value specific to the dielectric material. The above values are significantly different between the water content in glue and paper, with water content being 20 to 30 times higher than paper content.

Therefore, the generated electric field will be concentrated in the glue part, and the temperature of the paper will hardly rise, and only the temperature of the glue part will rise rapidly.

Incidentally, according to experiments conducted by the present inventors, it has been found that the adhesive area rises to 60 to 80°C within an application time of 0.2 to 0.5 seconds, but the paper does not rise by even 0.5°C.

FIG. 2 shows a second embodiment of the present invention, in which a rotating belt 14 having the same peripheral speed as the lower roll 2 is connected to the lower roll 2 in order to press the liner 9 against the corrugated core paper 8a. The roll surface is placed in pressure contact with a part of the circumferential surface of the roller. This belt 14 allows the sheets 9 and 8 to be spread over a fairly wide circumferential surface of the lower roll 2.
It becomes possible to uniformly press the parts a. Further, the grid electrode 11 is disposed in the loop of the endless belt 14 close to the circumferential surface of the lower roll 2, as in the previous embodiment, and causes the same temperature-rising gelation effect as described above.

(Effects of the Invention and Ideas) As described above in detail, according to the present invention, the core paper and the liner can be efficiently bonded by heating by dielectrically heating the sheet by applying a high frequency voltage between adjacent electrodes. At the same time, the surface pressure application means consisting of an endless belt or a container for supplying static pressure gas can apply almost uniform pressure over a fairly wide circumference, making it possible to avoid the high pressure associated with conventional pressure rolls. Since the external force that causes rigid body vibration is eliminated, the generation of noise can be eliminated and the breakage of the material paper can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a single facer showing an embodiment of the present invention, Fig. 2 is a side sectional view of a single facer showing another embodiment of the invention, and Fig. 3 is a side sectional view of a conventional single facer. FIG. Description of main parts of the figure 1... Upper roll, 2... Lower roll, 8... Core paper, 9... Liner, 11... Grid electrode, 12... Shot container, 14... Belt.

Claims (1)

[Claims] 1. In a single facer, which is composed of an upper roll and a lower roll that interlock with each other to form tiers of core paper, and a gluing device that applies glue to the top of the tier of the core paper after tier formation, the liner is pasted through the core paper after tier formation. A means for applying surface pressure consisting of an endless belt or a spray container for spraying static pressure gas is provided over a fairly wide desired peripheral surface of the lower roll, and the surface pressure is applied to the lower roll. The core paper and liner are bonded by dielectrically heating the glue under uniform pressure by arranging grid electrodes near the parts and applying a high frequency voltage between adjacent electrodes. A single phaser.