JP6969192B2 - Coating equipment and coating method - Google Patents

Description

The present invention relates to a coating device and a coating method for a dry lamination adhesive used for packaging materials such as foods, beverages and pharmaceuticals.

Conventionally, there are various laminating methods for laminating paper, aluminum foil, plastic film and the like, but the dry lamination method is often used for packaging materials such as foods and pharmaceuticals.

In the dry lamination method, for example, an adhesive solution is applied to the surface on which a barrier film of a plastic film is formed, and after drying, the adhesive surface is uncured and has some adhesiveness (tackiness). , The second plastic film is pressure-bonded and wound up to complete the curing of the adhesive and laminated. When heat resistance is required for the retort packaging material, the "waist" of the packaging material is required. It is suitably used when the total thickness is limited. The merit of this method is that the second plastic film does not require breathability for transpiration, so it can be applied to the bonding of a wide range of films and metal foils, and has high heat resistance, water resistance and resistance as an adhesive function. It is possible to demonstrate chemical properties.

In the dry lamination adhesive coating method, the adhesive is diluted with an organic solvent to an appropriate viscosity and applied to the film. 3 and 4 show two typical examples of the dry lamination adhesive coating method. In FIG. 3, the adhesive stored in the adhesive pan by the adhesive pan method is applied to the first film with a gravure roll, dried in a drying zone such as an oven, and then pressure-bonded to the second film and wound up. The outline of the dry laminating apparatus is shown.

FIG. 4 shows a chamber doctor type coating device. The chamber doctor is arranged so that the tip edge of the doctor blade (not shown) and the tip edge of the seal plate (not shown) are in sliding contact with the surface of the plate cylinder roll, so that the groove portion of the chamber doctor body and the plate cylinder roll can be formed. , Surrounded by a seal member (not shown) attached to both ends of the chamber body, a doctor blade, and a seal plate, forms a closed space (coating liquid chamber) with respect to the outside, and supplies this space. The coating liquid is supplied by a pump, and the coating liquid can be supplied to the plate cylinder roll side.

However, in the adhesive pan method, the adhesive in the adhesive pan is not sealed, and the solvent evaporates and the viscosity tends to increase. Also, in the chamber doctor method. In addition, since the adhesive circulates between the adhesive storage tank and the chamber doctor, curing is easy to proceed. Therefore, both methods have a drawback that gelation and plate clogging are likely to occur.

By the way, the time from mixing the adhesive to a state where it can be applied until it becomes unusable due to hardening, gelling, etc. is called pot life (pot life), but the adhesive with a particularly short pot life. When is used, the above-mentioned change progresses rapidly, so that a situation in which coating cannot be performed occurs.

On the other hand, the adhesive needs to be aged at a temperature of about 40 ° C. in order to accelerate curing after being applied to a film or the like. Adhesives for particularly highly functional retort applications and highly resistant applications require aging for 3 to 5 days. Adhesives that can shorten the aging time have a trade-off relationship of short pot life and difficulty in handling.

In particular, the two-component mixed type adhesive is more advantageous than the one-component type in terms of adhesiveness, durability, wide range of application to various plastics, metal foils, etc. (universality), aging time, etc. The life is short, and gelation occurs within a few hours after the preparation of the main agent, curing agent, and solvent. Curing and gelation progress during production, production becomes impossible, and similar symptoms occur during idling. There is a problem that it is difficult to use.

It has been proposed to mix and use a two-component mixed adhesive which is advantageous in terms of durability, versatility, and aging time immediately before use (Patent Document 1). However, it is only proposed that the adhesive should be mixed and used immediately before use, and it is described specifically what kind of device can use a two-component mixed type adhesive having a short pot life. It has not been realized and has not been realized.

Japanese Unexamined Patent Publication No. 2-84482

The present invention has been made to solve the above problems, and an object thereof is to apply an adhesive having a short pot life without causing coating defects (gelation, plate clogging). It is an object of the present invention to provide a coating device and a coating method capable of performing.

In order to solve the above problems, the invention according to claim 1 is a coating apparatus for applying a two-component mixed adhesive for dry lamination, which is used by mixing a main agent, a solvent, and a curing agent, at a coating portion. There,
A mixing section for mixing the main agent, the solvent, and the curing agent is provided.
The mixing portion is connected in close proximity to the front of the coating portion .
The coating portion is a coating device characterized by being a die coater type.

The invention according to claim 2 is a coating apparatus for applying a two-component mixed adhesive for dry lamination, which is used by mixing a main agent, a solvent, and a curing agent, at a coating portion.
In the first mixing section, a mixed solution of the main agent and the solvent is produced.
The curing agent and the mixed solution are mixed in the second mixing section, and the mixture is mixed.
The second mixing portion is connected in close proximity to the front of the coating portion .
The coating portion is a coating device characterized by being a die coater type.

The invention according to claim 3, said die coater, a coating roll, a coating liquid ejected from the die coater according to claim 1-2, characterized in that it comprises a function for reducing the space enclosed by the housing part It is the coating device according to any one of the above.

The invention according to claim 4 is a coating method characterized by using the coating apparatus according to any one of claims 1 to 3.

According to the coating apparatus and coating method of the present invention, the main agent, solvent, and curing agent are mixed immediately before coating, instead of mixing the adhesive in advance, so that even an adhesive having a short pot life can be gelled. Can be applied without any need. Further, since the die coater is preferably applied to the coated portion, the flow of the adhesive is unidirectional, and thickening due to long-term circulation and poor coating due to gelation do not occur.

(A) is a schematic diagram illustrating the configuration of the main part of the coating device of the first embodiment according to the present invention, and (b) is a schematic diagram showing the mode when the decompression function is used in (a). It is a schematic diagram which illustrates the structure of the main part of the coating apparatus of 2nd Embodiment which concerns on this invention. It is a schematic diagram which illustrates the structure of the conventional dry laminating apparatus. It is a schematic diagram which illustrates the structure of the main part of the conventional coating apparatus.

Hereinafter, the coating apparatus and coating method according to the embodiment of the present invention will be described with reference to the drawings. The same components are designated by the same reference numerals unless there is a reason for convenience, and duplicate explanations are omitted. In each drawing, the thickness and proportions of the components may be exaggerated for readability. Further, the present invention is not limited to the following embodiments without departing from the spirit of the present invention.

FIG. 1A is a schematic view illustrating the configuration of the main part of the coating device 100 according to the first embodiment according to the present invention, and shows a mode including a decompression chamber 9 described later. As described above, the coating device 100 of the first embodiment has at least a main agent tank 1, a solvent tank 2, a curing agent tank 3, a mixing unit 4, a coating unit 5, a liquid feeding pump 6, and a liquid transfer. The tube 7 and the valve 8 of the above are the main components.

In the coating device 100 of the first embodiment, the main agent, the solvent, and the curing agent of the two-component mixed adhesive are mixed in the mixing unit 4, and the mixed coating liquid is applied to the film 16 in the coating unit 5. The mixing portion 4 is closely connected to the front of the coating portion 5. As described above, in the coating apparatus 100 of the first embodiment, the main agent, the solvent, and the curing agent are mixed immediately before the coating, instead of mixing the adhesive in advance, so that even an adhesive having a short pot life can be gelled or the like. Can be painted without doing.

The mixing unit 4 is a mixer, and may be a so-called dynamic mixer provided with a drive unit and a shaft. It may be a mixer.

The coating portion 5 is preferably of a die coater method. The main agent, solvent, and curing agent are supplied in advance by the liquid feeding pump 6 at a predetermined flow rate, mixed in the mixing unit 4, and then in the width direction of the coating roll 15 (perpendicular to the paper surface) from the slit type discharge port of the die coater. ) Is applied at a uniform flow rate. Therefore, the die coater method has good controllability and reproducibility of the coating film thickness, and no residual liquid of the coating liquid is generated, so that loss can be reduced.

Furthermore, by applying the die coater method, the flow of the adhesive becomes unidirectional, and thickening due to long-term circulation and poor coating due to gelation do not occur. In addition, since there is no retention part or evaporation part of the coating liquid, it is also excellent in terms of property stability of the coating liquid.

The space surrounded by the die coater, which is the coating portion 5, the coating roll 15, the coating liquid discharged from the die coater, and the housing portion 10 is connected to a decompression pump (not shown), and as shown in FIG. It is preferable that the decompression chamber 9 has a function capable of depressurizing. In the case of a non-decompression chamber, especially when coating with a thin film thickness, it is necessary to bring the discharge port of the die coater close to the film 16 to the same distance as the film thickness, which causes runout (variation) of the film 16 and the coating roll 15. Interference can occur, effectively making coating difficult.

On the other hand, when the distance between the discharge port of the die coater and the film 16 is widened to about several times the coating film thickness, the liquid pool 11 between the discharge port and the film 16 becomes large as shown in FIG. 1 (b). At the same time, the pressure at the lower part of the liquid pool 11 rises due to the flow of air accompanying the rise of the film 16. Therefore, by using the decompression chamber 9 as the space, the shape of the liquid pool 11 can be controlled, and even if the distance between the die coater and the film 16 is about 10 times the coating film thickness, a thin film is formed. It is possible to apply a thick coating.

The liquid feeding pump is preferably a pump that does not pulsate and can accurately transport the liquid. Use precision gear pumps, vane pumps, screw pumps, and other pumps according to the accuracy of the coating amount. Pumps that generate pulsation, such as diaphragm pumps, are not preferable, but they can be used if measures are taken to suppress pulsation so as not to affect coating. The pump works in conjunction with the discharge meter and mixes as much as necessary for coating. Each discharge amount of the pump is controlled, and each is always supplied at a predetermined constant ratio. When the production line is stopped, the supply is automatically controlled to be stopped.

The valve 8 can be opened and closed when the device is stopped, and only the path of the solvent 2 is opened and washed when the device is stopped, such as at the end of production, so that the valve of the required path can be opened and closed as needed.

FIG. 2 is a schematic view illustrating the configuration of the main part of the coating device of the second embodiment according to the present invention, and shows a mode including a depressurizing chamber 9. The coating device 200 of the second embodiment includes a first mixing unit 4-1 and a second mixing unit 4-2, and the first mixing unit 4-1 produces a mixed liquid of the main agent and the solvent, and the second In the mixing unit 4-2, the curing agent and the mixed solution are mixed. Therefore, the coating device 200 of the second embodiment includes a tank for a mixed liquid (reference numeral: 1 + 2) of the main agent and the solvent, and a pump for sending the liquid. Two valves (reference numerals: 8-1, 8-2) are provided in front of the first mixing unit 4-1 and in front of the second mixing unit 4-2. The functions of the valves 8-1 and 8-2 are the same as those of the coating device 100 of the first embodiment.

As the adhesive, the effect of the present invention is exhibited in a two-component mixed type adhesive such as a urethane-based adhesive, an acrylic-based adhesive, an olefin-based adhesive, and an epoxy-based adhesive. The coating apparatus and coating method of the present invention are particularly suitable when the reaction rate is high (the open time is short). Further, for an adhesive which is one liquid such as a cyanoacrylate type but has a high reaction rate, it is effective to apply the coating apparatus and coating method of the present invention which is sealed until coating.

The coating method of the present invention is a coating method using the coating apparatus 100 or 200 of the present invention. Therefore, it is a coating method in which a main agent, a solvent, a curing agent, or a mixed solution of a main agent and a solvent, and a curing agent are mixed immediately before coating.

1 ... Main agent or its tank 2 ... Solvent or its tank 1 + 2 ... Main agent and solvent mixed solution, or its tank 3 ... Hardener or its tanks 4, 4-1 and 4- 2 ... Mixing part 5 ... Coating part (preferably a die coater)
6, 6-1, 6-2 ... Liquid feeding pump 7 ... Tube 8, 8-1, 8-2 ... Valve 9 ... Decompression chamber 10 ... Housing part (for decompression) )
11 ... Liquid pool 15 ... Coating roll 16 ... Film 17 ... Film 100, 200 ... Adhesive coated film 100, 200 ... Coating apparatus of the present invention

Claims (4)

It is a coating device that coats a two-component mixed adhesive for dry lamination, which uses a mixture of a main agent, a solvent, and a curing agent, at the coating part.
A mixing section for mixing the main agent, the solvent, and the curing agent is provided.
The mixing portion is connected in close proximity to the front of the coating portion .
The coating device is characterized in that the coating portion is of a die coater type. It is a coating device that coats a two-component mixed adhesive for dry lamination, which uses a mixture of a main agent, a solvent, and a curing agent, at the coating part.
In the first mixing section, a mixed solution of the main agent and the solvent is produced.
The curing agent and the mixed solution are mixed in the second mixing section, and the mixture is mixed.
The second mixing portion is connected in close proximity to the front of the coating portion .
The coating device is characterized in that the coating portion is of a die coater type. The coating according to any one of claims 1 and 2 , further comprising a function of reducing the pressure in the space surrounded by the die coater, the coating roll, the coating liquid discharged from the die coater, and the housing portion. Engineering equipment. A coating method comprising the coating apparatus according to any one of claims 1 to 3.

Images