JPS6242765A - Method for coating electrically conductive paint - Google Patents

Abstract

PURPOSE:To coat a low-viscosity electrically conductive paint on the surface of a plastic material by forming spiral grooves parallel to a coating roll and a stepping recessed groove communicating with the respective spiral grooves. CONSTITUTION:With respect to the method for coating an electrically conductive paint obtained by dispersing fine tin oxide particles in a solvent contg. a binder resin on the surface of a plastic material, plural spiral grooves 5 parallel to a coating roll 1 are provided at regular intervals and many recessed grooves 6 connecting the spiral grooves 5 are juxtaposed in parallel in the extending direction of the spiral grooves 5. The corner part 61 of the recessed groove 6 formed at the crossing part (a) with the spiral groove 5 and the linear part 62 of the recessed groove 6 is formed between respective grooves 5. Consequently, the paint flows obliquely in the spiral groove 5 and simultaneously flows in the cascade groove in longitudinal and lateral directions. Accordingly, a stripe pattern is not generated on the surface of the plastic material after transfer and the coating finish is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention applies a low-viscosity conductive paint, for example, a conductive paint made by dispersing ultrafine tin oxide particles in a solvent containing a binder resin, to the surface of a plastic material. Concerning a method for applying.

[Conventional technology]

A conductive paint is applied to the surface of a plastic material in order to reduce the electrical resistance value of the surface of the plastic material and prevent the adsorption of dust. As a means for applying conductive paint, there are air doctor coaters, blade coaters, rod coaters, knife coaters, which are originally used for printing,
There are various methods such as squeeze coater, reverse roll coater, gravure coke, casting, and spray coating, but each has its advantages and disadvantages, and the most ffi method is gravure coater.

The coating port used in the gravure coater has recesses formed on its surface that form various geometric patterns, and the transfer from the coating roll to the plastic material is performed as shown in Figure 4. While rotating the roll 1 around the rotational axis C-C, the plastic material P1, specifically, a plastic film, sheet or plate, is brought into contact with the surface of the application port 1 while rotating the roll 1 around the rotational axis C-C. This is done by sending it in a direction perpendicular to.

[Problem that the invention seeks to solve]

The gravure coater described above is originally used for printing, and is used to transfer highly viscous ink with tens of thousands of voids. When this gravure coater is used for full-surface solid printing, spotty striped patterns appear on the printed surface, but such striped patterns rarely pose a problem in the printing field. However, when a coating material such as a conductive coating material containing 60% or more of the solid content of inorganic tin oxide ultrafine particles is transferred to a plastic material using a coating roll for printing, the coating roll 1 contains If there is a difference in the coating finish depending on the shape of the recess, the electrical resistance value on the surface of the plastic material will not be uniform. Therefore, the occurrence of speckled striped patterns on the coated surface cannot be ignored.

Therefore, the inventors of the present invention searched for printing coating rolls engraved with various geometric patterns that would not cause striped patterns after transfer and would provide a good coating finish.

The applicator roll 1 shown in Fig. 5 has a plurality of diamond-shaped recesses 2 arranged in parallel in a spiral manner, the diagonal of which is longer in the direction of the axis of rotation (hereinafter referred to as the lateral direction) than the diagonal in the vertical direction perpendicular thereto. (hereinafter referred to as Combrest). Arrow A
indicates the rotation direction of the coating roll 1, that is, the plastic material (film, sheet, plate, etc.) to which the conductive paint is transferred.
) indicates the feeding direction. According to the combination shown in the figure, a spotted striped pattern appeared on the surface of the plastic material after transfer. The reason for this is thought to be as follows. That is, in the case of Combrest, the paint in the diamond-shaped recess 2 during transfer flows more easily in the horizontal direction indicated by arrow a in FIG. 6 than in the vertical direction indicated by the arrow already shown in FIG. The viscosity of conductive paints is significantly lower than that of printing inks, ranging from 50 to 300 centivoise. For this reason, the paint is transferred to the plastic material while spreading in the direction of lateral force a, and the surface of the plastic material after the transfer has shading of the paint in the vertical direction, resulting in a spotted striped pattern.

The coating finish of the coating roll 1 shown in FIG. 7 was also investigated. The applicator roll 1 shown in FIG. 7 has a plurality of diamond-shaped recesses 3 in which the vertical diagonal is longer than the horizontal diagonal (hereinafter referred to as "Elongate"). According to this, although a spot-like striped pattern did not appear as clearly as in the case of Combrest described above, slight shading of the paint occurred in the lateral direction on the surface of the plastic material after application. This is because the paint in the diamond-shaped recess 3 during transfer flows more easily in the vertical direction shown by the arrow in Figure 8 than in the horizontal direction shown by arrow a in Figure 8, so the paint spreads in the vertical direction. In other words, this is thought to be because the image is transferred to the plastic material while spreading in the feeding direction of the plastic material.

As described above, all of the coating rolls conventionally used for printing have had the problem that the paint has shading on the surface of the plastic material after transfer.

The present invention solves this problem by using a coating roll that combines the advantages of both Combrest and Elongate, and enables the application of conductive paint without striped patterns appearing on the surface of plastic materials. The purpose is to provide a method.

[Means for solving problems]

In order to solve the above problems, in the method of the present invention, a coating roll holding a conductive paint has the following configuration, a plastic material is brought into contact with the surface of the coating roll, and the plastic material is spread along the rotation axis of the coating roll. It is characterized by being sent in a direction perpendicular to.

Structure of the applicator roll It has a plurality of spiral grooves parallel to each other at regular intervals, and a large number of step-shaped grooves that interconnect these spiral grooves are arranged in parallel in the extending direction of the spiral grooves. Corner portions of the grooves are formed at intersections with the spiral grooves, and straight portions of the grooves are formed between the spiral grooves.

[For production]

According to the above means, during transfer, the low-viscosity conductive paint flows obliquely through the spiral groove, then enters the stepped groove and flows in the vertical and horizontal directions. That is, the plastic material flows in the vertical and horizontal directions while being deviated obliquely with respect to the feeding direction of the plastic material. Therefore, the vertical spread of the paint is the same as that of the above-mentioned Elongate, and the horizontal spread of the paint is the same as that of Combrest. Therefore, no shading of the paint occurs on the surface of the plastic material after transfer.

〔Example〕

As described above, the coating method of the present invention involves bringing the plastic material into contact with the surface of the coating roll holding the conductive paint and sending the plastic material in a direction perpendicular to the rotational axis of the coating roll. This method includes, for example,
The coating roll illustrated in FIG. 3 can be suitably used. This coating roll will be explained below.

FIG. 1 shows the groove shape formed on the surface of the coating roll 1 of the present invention. In the figure, the groove portion is indicated by a solid line.

Figure 2 is a partially enlarged view of Figure 1, Figure 3 is XX of Figure 2.
It is a sectional view along a line. As is clear from these, the coating roll 1 has a plurality of mutually parallel spiral grooves 5 at regular intervals, and step-like concave grooves that interconnect these spiral grooves 5. 6 are arranged in parallel in the direction in which the spiral grooves extend, and are formed between the spiral grooves. When the conductive paint was transferred onto a plastic material using such a coating roll 1, no ci-light of the paint occurred on the surface of the plastic material after the transfer. The reason for this is thought to be as follows.

That is, during transfer, the paint flows obliquely as shown by arrow C through the spiral grooves 5, and then enters the stepped grooves 6.
It flows in the longitudinal direction d and the lateral force direction e. In other words, the plastic material flows in the longitudinal direction d and the lateral force direction e while being shifted obliquely to the feeding direction A of the plastic material.

Further, the centrifugal force acting on the paint as the applicator roll l rotates helps spread the paint in the vertical direction d and the horizontal direction e.

C. Effects of the Invention] According to the method of the present invention, the following effects are achieved due to the structural characteristics of the coating roll used for its implementation. That is, when transferring conductive paint to a plastic material, the paint flows diagonally through a large number of spiral grooves and vertically and horizontally through a large number of stepped grooves, so that the paint spreads flatly. . Therefore, striped patterns caused by the shading of the paint do not occur on the surface of the plastic material after transfer, and the coating finish is good. Therefore, the surface electrical resistance of the plastic material coated with conductive paint becomes uniform in all parts, and even if the plastic material is required to be transparent, the transparency will not be impaired by the striped pattern and the product will be sold. You can get high value products.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the surface condition of the coating roll used in the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG.
4 is a perspective view showing the state when conductive paint is transferred from the applicator roll to the plastic material, FIG. 5 is an explanatory view showing the combination, and FIG. FIG. 7 is an explanatory diagram showing the paint flow in the recess of the Combrest, FIG. 7 is an explanatory diagram showing the elongate, and FIG. 8 is an explanatory diagram showing the paint flow in the recess of the elongate. 1... Application roll, 5... Spiral groove, 6... Concave groove,
61...Corner part of the groove, 62...Straight line part of the groove.

Claims (1)

[Claims] (1) A method of applying a low-viscosity conductive paint to the surface of a plastic material, in which a coating roll holding the conductive paint has the following configuration, and the plastic material is brought into contact with the surface of the coating roll. A method for applying a conductive paint, characterized in that the plastic material is fed in a direction perpendicular to the axis of rotation of a coating roll. Structure of the applicator roll It has a plurality of spiral grooves parallel to each other at regular intervals, and a large number of step-shaped grooves that interconnect these spiral grooves are arranged in parallel in the extending direction of the spiral grooves. Corner portions of the grooves are formed at intersections with the spiral grooves, and straight portions of the grooves are formed between the spiral grooves.