JPS6238026B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminator for laminating two webs, for example, two types of plastic films or a plastic film and an aluminum foil.

In this type of laminator, generally, as shown in FIG. 1, after applying an adhesive 3 to a web 2 using a gravure coater 4, the web 2 is passed through a drying device 6 to dry the adhesive 3 with hot air. 2 glue 3
Another web 8 is pasted through the web.

What becomes a problem here is the content of the solvent in the adhesive 3 applied to the web 2 by the gravure coater 4. This solvent improves the transferability of the adhesive 3 to the web 2;
In other words, the content of solvent in the adhesive is essentially necessary and sufficient at 40 to 45%, although this greatly affects workability. In fact, manufacturers purchase adhesives with a solvent content adjusted to 40 to 45% of the resin content (polymer). However, in the conventional configuration in which the gravure roll 13 is immersed in the adhesive in the pan in the gravure coater 4, the viscosity of the adhesive increases over time due to volatilization of the solvent, resulting in poor coating accuracy.

Therefore, in the past, the solvent content was generally 40~
The reality is that adhesives with a solvent content of 70 to 75% are used by adding a solvent to the adhesive adjusted to 45%. That is, the diluted adhesive 3 is applied to the web 2 using a gravure coater 4,
g/m ² and after drying, the coating film of adhesive 3 is
It is assumed that it will be ^about 1.4g/m2.

First of all, this method is expensive because the solvent used is generally an organic solvent such as toluene. Pollution problems arise. Adhesive 3 after being applied to web 2
The drying process takes time, which means that the drying chamber becomes larger. There is a problem.

If an adhesive whose solvent content is adjusted in advance to 40 to 45% can be used as is, these conventional problems can be solved at once. This invention was proposed from this point of view, and its feature is that adhesive with an appropriate solvent content of 40 to 45% is supplied to the circumferential surface of the gravure roll. At the point.

Next, the details will be explained based on the drawings.
In FIG. 1, the laminator according to the present invention is summarized as follows.
a gravure coater 4 that applies an adhesive 3 to a web 2 continuously fed out from a raw roll 1;
A drying device 6 that passes the web 2 coated with the adhesive 3 through a drying chamber 5 and dries it with hot air; and a second web 8 that is continuously fed out from another raw roll 7 to the web 2 after the drying process. and a means 9 for laminating the webs through an adhesive 3, and the web after lamination is wound onto a take-up reel 10.

In FIG. 2, the gravure coater 4 consists of a back-up roll 11, a coating roll 12 which presses the web 2 between the rolls 11, and a gravure roll 13 which presses the roll 12. The gravure roll 13 is provided with a supply nozzle 16 for the adhesive 3 at a position downstream from the contact point 15 with the coating roll 12 in the roll rotation direction, and a supply nozzle 16 for the adhesive 3 is disposed at a position downstream from the contact point 15 in the roll rotation direction. A doctor blade 17 is provided to scrape off the excess portion 3a of the adhesive 3 supplied to the circumferential surface of the roll. And the supply nozzle 16
The adhesive 3 supplied to the circumferential surface of the gravure roll 13 is applied to the web 1 via the coating roll 12 by dislocation.

In FIG. 3, the supply nozzle 16 has a nozzle body 19 consisting of a hollow pipe with both ends closed, and has a length spanning the width direction of the gravure roll 13, and faces the roll circumferential surface closely with a slight clearance C. An adhesive outflow hole 20 is provided on the side of the nozzle body 19 facing the roll circumferential surface. The outflow holes 20 may be in the form of a slit that is opened in series over the longitudinal direction of the nozzle body 19, or may be in the shape of holes that are opened at predetermined intervals along the longitudinal direction.

The gravure coater 4 is attached with a sealed storage tank 21 for storing the adhesive 3.
The solvent content is adjusted to an appropriate value within the range of 40 to 45% by weight in the storage tank 21, and is fed from the tank 21 through the supply pipe line 22 to the supply nozzle 16 by the pump 23, and the nozzle body 19 It is supplied to the circumferential surface of the gravure roll 13 through the outflow hole 20 . The adhesive 3 is stored in a storage section 2 with a wedge-shaped cross section formed between the gravure roll 13 and the nozzle body 19.
5, the adhesive 3 moves along the circumferential surface of the roll 13 due to its own viscosity, forming a so-called boundary layer. The flow within the layer is caused by the roll 13
The adhesive 3 has a velocity component not only in the tangential direction but also in the radial direction.
Due to the shape of 5, the roller can easily and surely enter the groove on the circumferential surface of the roll. The optimum viscosity of the adhesive 3 at that time is within the range of 40 to 45% by weight, expressed as the solvent content.

The excess portion 3a of the adhesive 3 supplied to the circumferential surface of the gravure roll 13 is scraped off by a doctor blade 17 and collected in the storage tank 21. 29 in the diagram
is the recovery pipe.

An adhesive tank 30 and a solvent tank 31 are attached to the storage tank 21, and the adhesive 3 whose solvent content is adjusted to an appropriate value within the range of 40 to 45% by weight is piped from the adhesive tank 30. The storage tank 21 can be replenished via the line 32 , and the solvent 33 can be replenished from the solvent tank 31 into the storage tank 21 via the line 34 .

In the storage tank 21, the recovered surplus 3a of the adhesive 3 mentioned above and the new adhesive 3 to be replenished are stored.
and the solvent 33 is a stirrer 35 which also serves as a viscosity measuring element.
The mixture is mixed and stirred. The stirrer 35 is immersed in the stored adhesive 3b in the tank and is rotated by a motor 36.

Replenishment of the adhesive 3 into the storage tank 21 is performed by a liquid level control means comprising, for example, a float level switch 37 and a control valve 38 provided in the middle of the pipe line 32. That is, the level switch 37 detects a change in the liquid level of the adhesive 3 in the storage tank 21, and upon this detection, the control valve 38 is operated to control the amount of adhesive 3 flowing into the storage tank 21.

Replenishment of the solvent 33 to the storage tank 21 is carried out by using the stirring bar 35, a motor 36 that rotationally drives the stirring bar 35,
The control valve 4 provided in the middle of the above-mentioned solvent supply pipe 34
0 and the viscosity of the stored adhesive 3b is detected and controlled. That is, the viscosity of the storage adhesive 3b is proportional to the solvent content, and when the solvent content is 40 to 45% by weight,
Set a certain viscosity in the range of 3 and
The fact that the viscosity of b exceeds the set viscosity is detected by the rotational resistance of the stirrer 35, and the solvent 33 is replenished by operating the control valve 40 based on this detection signal. The amount of this new replenishment of the solvent 33 is equal to the amount of solvent volatilized from the recovered surplus portion 3a of the adhesive 3 supplied to the gravure roll 13.

In this case, the solvent content of the adhesive 3 supplied from the storage tank 21 to the gravure roll 13 via the supply nozzle 16 is controlled to an appropriate value within the range of 40 to 45% by weight. According to experiments conducted by the present inventor, when adhesive 3 with a solvent content of 43% by weight is applied to web 2 at a rate of approximately 2.8 g/m ² using gravure coater 4, the adhesive 3 after drying is approximately 1.4 g/m 2 . It became ^m2 . Further, the coating can be performed at high speed without any change from the conventional method, and the drying time of the applied adhesive 3 can be shortened by the amount of the solvent content reduced.

Although the illustrated example is as described above, the new adhesive 3 and solvent 33 can be supplied even if these supply pipes 32 and 34 are finally integrated into one and replenishment control is performed using one control valve. good. Needless to say, in most cases, the adhesive 3 and the solvent 33 are replenished into the storage tank 21 using a pump.

Furthermore, the adhesive 3 is temporarily stored between the gravure roll 13 and the supply nozzle 16, and the adhesive 3 is kneaded into the grooves on the circumferential surface of the gravure roll 13. Although it has been confirmed that the adhesive 3 has an extremely significant effect on the adhesion of the adhesive 3, the present invention is not limited thereto. It may be a form.

In addition, the web 2 may be in direct contact with the gravure roll 13, and the drying device 6 may also take various forms.

As explained above, according to the present invention, the excess portion 3a of the adhesive 3 supplied from the supply nozzle 16 to the circumferential surface of the gravure roll 13 is transferred to the doctor blade 17.
The new adhesive 3 containing the solvent is scraped off and collected in the storage tank 21.
In addition to replenishing the consumed amount, add solvent 3
3 is added again by controlling the inflow amount to compensate for the shortage, and the mixture is mixed and stirred using the stirrer 35. and tank 2
The viscosity, that is, the solvent content, of the stored adhesive 3b in 1 is set to a value suitable for application by gravure roll 13 (usually
The adhesive 3 with the solvent content kept at a constant value is supplied to the gravure roll 13 via the supply nozzle 16. Therefore, it is possible to ensure that the adhesive 3 is applied to the web 2 with high precision by the gravure coater 4 while feeding the web 2 at high speed, and to suppress unnecessary addition of solvent. 1. It is also possible to use a commercially available adhesive 3 with a solvent content of 40 to 45% by weight as is, and the amount of replenishing solvent 33 to be used is drastically reduced, resulting in cost reduction. Second, the drying device 6 and exhaust gas equipment can be smaller than conventional ones, and less thermal energy is required for drying.
Furthermore, the drying time can be shortened, which is advantageous in these respects as well.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic front view of a laminator according to the present invention, and FIGS. 2 and 3 are enlarged front views of essential parts thereof. 2...Web, 3...Adhesive, 3a...Excess amount of adhesive recovered from the gravure roll, 3b...
...Adhesive stored in storage tank, 4... Gravure coater, 6... Drying device, 8... Web, 9... Means for laminating webs together, 13... Gravure roll, 16... Supply nozzle, 17... ... Doctor blade, 19 ... Nozzle body, 20 ... Adhesive outflow hole, 21 ... Storage tank, 22 ... Adhesive supply pipe from storage tank, 25 ... Storage section, 30 ...
...Adhesive tank, 31...Solvent tank, 32...
Adhesive supply pipeline to the storage tank, 33...Solvent, 34...Solvent supply pipeline to the storage tank, 3
5... Stirrer, 36... Motor, 37... Level switch.

Claims (1)

[Scope of Claims] 1. A gravure coater 4 that applies an adhesive 3 containing a solvent to a continuously fed web 2, and a drying device 6 that dries the adhesive 3 applied to the web 2.
In the laminator, the gravure roll 13 of the gravure coater 4 is coated with the gravure roll 13 of the gravure coater 4. a supply nozzle 16 for supplying the adhesive 3 to the circumferential surface of the roll 13; and a surplus portion 3a of the adhesive 3 supplied to the circumferential surface of the roll 13;
A doctor blade 17 is provided to scrape off the
A recovery conduit 29 has a sealed storage tank 21 for storing the adhesive 3, and receives the excess portion 3a of the adhesive 3 scraped off from the peripheral surface of the gravure roll 13 by the doctor blade 17 into the storage tank 21.
, an adhesive supply pipe line 32 for receiving a new adhesive 3 containing a solvent, and a solvent supply pipe line 34 for receiving a solvent 33, respectively.
It has a means for mixing and stirring the stored adhesive 3b in the storage tank 21 with a stirrer 35, a means for controlling the liquid level of the stored adhesive 3b in the storage tank 21 by adjusting the inflow amount of new adhesive 3, and a stirring means. The viscosity of the adhesive 3b stored in the storage tank is detected by the rotational resistance of the child 35, and the solvent 3 is
3, and a means for controlling the viscosity to a set value by adjusting the inflow amount of the adhesive 3, and a pipe line 22 for supplying the adhesive 3 from the storage tank 21 to the supply nozzle 16. laminator. 2 The adhesive 3 supplied from the supply nozzle 16 to the circumferential surface of the gravure roll 13 has a solvent content of 40 to 45
The laminator according to claim 1, wherein the laminator is set to a predetermined value within a range of weight %.