JPH0796103B2 - Solventless coating agent coating equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a solventless coating agent coating apparatus.

(Prior Art) In recent years, a solvent-free coating agent has been actively studied because of advantages such as safety, resource saving, and energy saving. In particular, solventless dry lamination and the like have already been put to practical use, and many solventless adhesives and coating devices have been supplied to the market.

Since this solventless coating agent is not diluted with a solvent,
It has a high viscosity and has been difficult to coat conventionally. In the case of the above-mentioned solventless dry lamination, the coating shown in Fig. 2 (Paper and Plastics, November 1981, pp. 1-34) is shown. A lot of engineering equipment is adopted.

(Problems to be Solved by the Invention) However, in the case of the conventional coating apparatus shown in FIG.
When the supply rolls 3 and 4 are rotated in the direction of the arrow, the boundary portion A between the supply rolls 3 and 4 and the solventless coating agent 22 and the air
It is easy to get air into. However, the viscosity of the solventless coating agent is generally high, it is difficult to remove air bubbles created by the entrained air, and a large amount is present in the supply section 23. Also mixed in.
This air bubble not only deteriorates the appearance of the product and reduces the commercial value, but especially in the case of a reactive coating agent in which the curing reaction of the solventless coating agent proceeds by a radical reaction, it is caused by oxygen. There is a problem that reaction will occur and it will not cure,
It is necessary to prevent the entrainment of air in the supply unit 23.

Therefore, it is an object of the present invention to provide a coating apparatus that does not cause air entrapment in the supply section of a reactive solventless coating agent.

(Means for Solving the Problems) The present invention provides a coating apparatus having two supply rolls, one or two of which is rotated in a direction of entraining air in a solventless coating agent. The present invention relates to a coating device for a solventless coating agent, characterized in that an auxiliary roll that rotates in the forward rotation direction is provided at the boundary between the solventless coating agent and air.

That is, in the apparatus of the present invention, as shown in FIG. 1, auxiliary rolls 5 and 6 are installed at the boundary between the supply rolls 3 and 4, the solventless coating agent 22 and the air, and these auxiliary rolls are respectively supplied. 3 and 4 are rotated in the forward rotation direction.

As shown in FIG. 1, at the boundary portion between the auxiliary rolls 5 and 6, the solventless coating agent 22 and the air, the auxiliary rolls are rotated in the opposite direction to the rotation direction of the supply rolls, and thus are rotated outward. , Air entrapment does not occur. Here, the auxiliary roll must be pressed with a certain pressure in order to prevent air from being entrained between the auxiliary roll and the supply roll 3 or 4. Therefore, if the supply roll is metal,
The auxiliary roll for the supply roll is a roll coated with rubber or synthetic resin, and when the supply roll is a roll covered with rubber or synthetic resin, the auxiliary roll is a metal roll or coated with rubber or synthetic resin. And roll it. The pressing pressure at this time has an optimum value depending on the coating conditions such as the diameter of each roll, the hardness of the rubber, the temperature, the rotation speed, and the viscosity of the solventless coating agent, so it should be determined for each condition. is there.

The rotation speed of the auxiliary roll does not necessarily have to be the same as that of the supply roll. If the rotation speed is too high, the solventless coating agent will be moved from the supply section to a portion different from the original coating agent transfer step. Therefore, a blade for scraping off the solventless coating agent may be provided, but it is more desirable to minimize the rotation speed so as not to move.
However, when the rotation is stopped, only a specific part is worn, so it should be rotated slightly.

Solventless in the solventless coating agent according to the present invention, methyl isobutyl ketone, methyl ethyl ketone, ketones such as acetone, xylene, aromatic compounds such as toluene, methanol, butanol, organic solvents such as alcohols such as propanol and It means substantially free of a solvent such as water. However, depending on the application of the coating agent, these solvents may be present, and these solvents are preferable,
20% by weight or less of the coating composition, particularly preferably 10% by weight
It may be present below, most preferably up to 5% by weight.

The reactive solventless coating agent according to the present invention, for a synthetic resin, includes a crosslinking agent that reacts with the synthetic resin, a curing agent, if necessary, a pigment, a dye, a plasticizer, an antioxidant, Antifoam,
A composition containing a leveling agent, a fungicide, an insect repellent, a fragrance, an ultraviolet absorber, a modifier such as a waterproofing agent, which does not substantially contain a solvent such as an organic solvent and water, and is to be coated. It is liquid and fluid at the time of coating, and is cured or non-fluidized by crosslinking, polymerization, addition condensation reaction or the like on the article to be coated after coating. Examples of the solventless coating agent include paints, adhesives, pressure-sensitive adhesives, coating agents, printing inks and the like.

The synthetic resin forming the reactive solventless coating agent has a reactive functional group or a reactive unsaturated bond at the terminal or side chain, and is reacted with a crosslinking agent, a curing agent, or the like, or heating, It causes a curing reaction by energy such as light, ultraviolet rays, and electron beams.

FIG. 3 is a side view of the coating apparatus of the present invention. When the adhesive film 20 is manufactured using this apparatus, the polyester film 18 is guided between the backup roll 1 and the supply roll 4 by the guide rolls 8 and 9. At the boundary between the supply rolls 3 and 4, the solventless coating agent 22 and the air,
Auxiliary rolls 5 and 6 are installed, respectively. As a result, the solventless coating agent 22 is supplied to the supply roll 4 without being entrained with air, and the coating agent is applied to the lower surface of the polyester film 18. The polyester film 18 coated with the coating agent is further guided by the guide roll 10 between the metal roll 15 and the rubber coating roll 7. The polyethylene film 19 is guided between the roll sets by the guide roll 11, laminated on the applied coating material, and irradiated with an electron beam in the electron beam irradiation device 21. here,
The coating agent is cured by electron beam irradiation. Next, the obtained film having a sandwich structure is guided to rolls 16 and 17, and then the polyethylene film is peeled off and wound up through a guide roll 12. On the other hand, the polyester film coated with the adhesive is wound up as adhesive tape 20 via the guide rolls 13 and 14.

In the drawings, 1, 3, 15 and 16 are metal rolls, and 2, 4, 7 and 17 are rubber coated rolls.

(Examples) Next, the present invention will be described in detail based on examples, but the present invention is not limited thereto.

Example 1 The coated surface was subjected to corona treatment so as to have a surface density of 50 dyne / cm or more.
A radiation-curable solventless adhesive was applied to a 38 μ thick polyester film at a rate of 10 g / m ² using the device shown in FIG. 3, and a polyethylene film with a thickness of 50 μ was laminated and then adhesive An adhesive film was prepared by irradiating with an electron beam so that the adhesive surface would be 4 Mrad.

Comparative Example Using the same device as in FIG. 3 except that the auxiliary roll was omitted,
An adhesive film was prepared in the same manner as in Example 1.

The number of bubbles and the curability of the adhesive films obtained in Examples and Comparative Examples were tested. The results are shown in the table below.

The number of bubbles was observed by enlarging the surface of the prepared adhesive film by 50 times with an optical microscope.

In addition, for the curability test, an SUS430BA plate with an adhesive film of 6 kg /
After applying pressure of 2 cm / min under pressure of 10 cm / cm ²
The surface of the SUS plate at the time of peeling at a speed of 60 m / min was visually observed with the naked eye while being treated at 65 ° C. for 7 days while applying pressure.

(Effects of the Invention) According to the present invention, by installing an auxiliary roll at the boundary between the roll, the coating agent, and the air, air entrapment in the solvent-free coating agent supply section is prevented, and no air bubbles are mixed. A good product can be obtained.

[Brief description of drawings]

FIG. 1 is a side view of a main part of a coating apparatus showing one embodiment of the present invention, FIG. 2 is a side view of a conventional coating apparatus, and FIG. 3 is a coating apparatus showing one embodiment of the present invention. FIG. Explanation of symbols 1 ... Backup roll, 2 ... Coating roll, 3,4 ... Supply roll, 5,6 ... Auxiliary roll, 18 ... Polyester film, 19 ... Polyethylene film, 20
…… Adhesive film, 21 …… Electron beam irradiation device, 22 …… Solventless coating agent, 23 …… Solventless coating agent supply section, A …… Air entrainment section

Claims (1)

[Claims] 1. A coating apparatus having two supply rolls, wherein any one or two of the rolls rotates in a direction in which air is drawn into the solventless coating agent. A coating apparatus for a solventless coating agent, characterized in that an auxiliary roll that rotates in the forward rotation direction is provided at the boundary portion.