JPH0157631B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solvent-free laminator for producing laminated webs made of plastic film, paper, aluminum foil, etc. using a one-component or two-component urethane solvent-free adhesive. It is.

A first object of the present invention is to provide a control method that optimizes the amount of adhesive with a short pot life retained in the coating portion, particularly in the adhesive bank between the first and second rolls.

The second object of the present invention is to control the temperature of the area where the adhesive is transferred to the web at a constant level.
The object of the present invention is to provide a method for minimizing variations in coating amount.

Furthermore, the third object of the present invention is to improve the appearance of the coated surface, increase the coating speed, and reduce the variation in coating amount, especially when using a high viscosity one-component ester adhesive or two-component adhesive with a short pot life. The aim is to make it possible to expand the range of combinations of laminate webs.

FIG. 1 shows a conventional coating method using a two-component solvent-free adhesive. The coating part 8 consists of No. 1 roll 1 (rubber roll), No. 2 roll 2 (metsuki roll with warm water circulation), No. 3 roll 3 (rubber roll that was dropped during coating), and No. 4 roll 4 (warm water circulation). A group of four rolls (Tametsuki Roll), a dam 10 for mixing two liquids, a supply hose 11,
11', pump 12, 12', tank 13, 13'
It consists of a two-component adhesive supply device. In the coating section 8, the first web 5 to which the adhesive has been transferred is pressure-bonded by the second web 6 and the laminate section 9 to form a laminate web 7. In this conventional adhesive supply method, the pumps 12, 12' are synchronized with the coating speed to perform ratio operation, but in reality, the viscosity of the adhesive, the coating speed, and the relationship between the web and the adhesive Since the amount of coating changes due to the influence of complex factors such as wettability, it is necessary to constantly adjust the ratio between the pump and coating speed each time these factors change. If the ratio is not appropriate, the coating film will break due to insufficient adhesive, or adhesive will overflow from the dam. In the case of adhesives with a long pot life, excess or deficiency of these adhesives was not a major problem, but in the case of one-component polyester adhesives or two-component adhesives with short pot lives, the supply of adhesive Too much or too little will result in variations in the residence time of the adhesive in the coating area, resulting in serious product defects such as thickening of the adhesive, variations in the coating amount due to gelation, and the occurrence of coating streaks.
In the conventional method, the temperature of the adhesive transfer part, especially the part where the adhesive layer is split onto both the first web 5 and the third roll 3 according to the principle of film splitting, is the temperature of the adhesive (the temperature of the second roll 3). temperature), the temperature of the first web heated by the No. 4 roll 4, the amount of adhesive applied, the coating speed, the heat capacity of the first web, etc. It will change over time. The condition of this split portion has a particularly large effect on the appearance of the web, and if the split is not perfect, it may cause spots, orange peel, etc. This phenomenon is more likely to occur as the viscosity of the adhesive increases, so to prevent this, it is necessary to keep the temperature of the split part constant regardless of the amount of adhesive applied, coating speed, and heat capacity of the first web. There is. In any case, in conventional methods, when using high viscosity adhesives with short pot lives, residence time, failures caused by split points, etc. can affect coatable adhesives, coating speeds, laminated webs, etc. Since combinations and the like were limited, a method for producing high-quality laminate webs under a wider range of conditions was desired.

FIGS. 2 and 3 show embodiments of the present invention that can solve the above problems, and the details thereof will be explained below. Tanks 13, 13', pump 12,
12', supply hoses 11, 11', and a dam 10, the adhesive 14 is transferred onto the first web 5 by a coating section consisting of four rolls. Reference numeral 15 denotes an infrared heating device that emits far infrared rays with a wavelength of about 3 μm to heat the adhesive and the first web immediately before the transfer section. A radiation thermometer 16 detects the temperature of the adhesive 14 or the film split portion divided into the first web 5 and the third roll 3. The temperature of the split section detected by the radiation thermometer 16 is fed back to the infrared heating device via a temperature controller, and the output is controlled so that the temperature of the split section is constant. The radiation thermometer 16 has a small detection area and is equipped with a filter to selectively detect infrared rays with a wavelength of around 3 μm, and is capable of detecting only the temperature of the adhesive split portion. This prevents disturbances caused by reflections from the plating surface in step 4.

FIG. 3 shows an adhesive retention amount control device, which includes an inlet member 18, a mixer 19, a hot water channel 20, and an outlet 21.
The dam 10 having a dam 10 is disposed close to the arcuate portions of the first roll 1 and the second roll 2, and supplies adhesive and regulates the amount of retention in the adhesive bank 22. The state shown in FIG. 3 is a case where the amount of retention in the bank 22 is appropriate, and the adhesive interface is located on the dam 10 side from the phototube optical axis 17. When the optical axis 17 is completely formed, the pump drive device is controlled to operate the pumps 12, 12'. On the contrary, optical axis 17
is blocked by the adhesive interface, that is, when the adhesive interface exceeds the optical axis 17 and overflows from the dam 10, the pumps 12, 12' are controlled to be stopped. Usually, the second roll 2 is about the same as the first roll 1.
Because it rotates at 10 times the circumferential speed, the traction force of the adhesive acting between the roll and the dam is greater on the second roll, and due to the action of gravity, the number 1 roll and the dam are always connected. Adhesive overflows from the 10-space. Therefore, the optical axis 17 needs to be placed close to the dam 10 and the No. 1 roll 1.

With the above configuration, after directly detecting the temperature of the adhesive split portion with the radiation thermometer 16,
The output of the infrared heating device is controlled to keep the temperature of the split part constant, so even if the temperature of the first web, heat capacity, adhesive coating amount, and coating speed change, the temperature of the adhesive split part remains constant. is kept constant. The phototube optical axis 17 provided close to the No. 1 roll 1 and the dam 10 detects an increase or decrease in the retention amount of the adhesive bank 22 regulated by the No. 1 roll 1, the No. 2 roll 2, and the dam 10. The operation of the adhesive pump is controlled by
It is maintained optimally and consistently without being affected by coating speed, coating amount, or web wettability.

According to the present invention, the temperature of the adhesive transfer part, especially the adhesive split part, can be kept constant without being affected by the temperature of the first web, heat capacity, adhesive coating amount, and coating speed. Even if these factors change, the condition of the split portion remains constant. Therefore, the adhesive coated surface can be kept smooth. Therefore, there will be no unevenness, orange peel, or spots,
The appearance of the laminate web is extremely good. Particularly when using high viscosity adhesives such as ester-based or two-component adhesives, it is possible to achieve coating speeds and laminate compositions that were impossible with conventional methods due to unevenness, orange peel, and blobs. Even in this case, a laminate web with a good appearance can be obtained. In addition, excess or deficiency of the adhesive is detected by the phototube optical axis 17 placed close to the first roll 1 and the dam 10, and the supply of the pump is controlled, so that the amount of adhesive retained is kept optimal and constant. It will be done. As a result, even if a one-component ester adhesive or a two-component adhesive with a short pot life is used, the residence time is short, so the adhesive will not thicken or gel. When the adhesive thickens, the amount of coating increases, and when it gels, it not only increases the amount of coating, but also causes spots on the coated surface.
Orange peel occurs and causes product defects, but
According to the present invention, it is possible to prevent these problems caused by adhesives having a short pot life, and it is possible to stabilize the product and reduce the loss rate.

By optimally controlling the amount of adhesive retained and by controlling the temperature of the split part at a constant level, high-quality laminate webs can be produced using high-viscosity ester adhesives with short pot lives or two-component adhesives. It can be manufactured over a wide range and stably.

Although it is clear that the best method is to use the above two methods in combination, using either method alone is superior to the conventional method.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional coating method using a two-component solvent-free adhesive. FIG. 2 shows a coating control method for a solvent-free laminator according to the present invention. FIG. 3 shows an adhesive retention amount control device. In the diagram: - 1...1st roll, 2...2nd roll, 3...
3rd roll, 4...4th roll, 5...first web, 6...second web, 7...laminate web, 8...coating part, 9...laminate part, 10...dam, 11 , 11'... Supply hose, 12, 12'... Pump, 13, 13'... Tank, 14... Adhesive, 15... Infrared heating device, 16... Radiation thermometer, 17... Phototube optical axis .

Claims (1)

[Claims] 1. An adhesive supply dam is provided between the No. 1 roll and the No. 2 roll, and an infrared heating device is provided just before the transfer portion of the No. 3 roll, and the heating device is used to detect the temperature of the adhesive at the split portion. and a coating control method for a solvent-free adhesive laminator, which is controlled by the detected temperature. 2. An adhesive supply dam is provided between the No. 1 roll and the No. 2 roll, and an infrared heating device is provided immediately before the transfer section of the No. 3 roll, and an optical axis of a phototube is arranged close to the No. 1 roll and the dam. A coating control method for a solvent-free adhesive laminator, which detects the amount of adhesive and controls a pump that supplies adhesive to the dam.