JP2002355608A - Method for manufacturing colored spheres - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing colored spheres of which the surfaces are partially colored and coated at a low cost. SOLUTION: Spheres are bonded to a work surface and the surfaces of the spheres on the side opposite to the work surface are coated with a color paint by screen printing and, after the color paint is dried, the spheres are again peeled from the work surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a large amount of spheres (hereinafter referred to as "colored spheres") in two or more colors at low cost.

[0002]

2. Description of the Related Art Colored spheres rotatably held on a substrate are used as pixels, and the spheres are rotated by an electric or magnetic field to change the color directed to the surface. Various proposals have been made. Since these display images and characters with reflected light, their eyes are less tiring than CRTs and backlight-type liquid crystals that emit light, and they are compared with other reflective light type display devices or media such as electrophoresis. It has features such as easy acquisition of contrast.

[0003] Colored spheres are prepared by combining two or more kinds of resins and waxes having different colors in a molten state and manufacturing them into spheres by flying, dropping, hot cutting, etc. A method of forming a material having a color different from the sphere on the surface as a thin film by vapor deposition or sputtering on a part of the surface, or applying a colored paint different from the sphere (including white, the same applies hereinafter) has also been proposed. I have.

[0004]

However, in the method using two or more kinds of resins and waxes having different colors, the material is greatly restricted in order to finish them in a spherical shape so that they are not mixed, and the spherical magnet is colored. It is difficult to use this method.

On the other hand, a method of forming a material having a color different from that of a sphere as a thin film on the surface by vapor deposition or sputtering or the like has large restrictions on the material and is costly. Also, since a thin film is formed, periodic cleaning is required, which further increases the production cost.

On the other hand, the method of producing colored spheres by coating is advantageous in terms of material restrictions and cost, but
In the method of using a spray or the method of half-embedding and coating the sphere, periodic cleaning is necessary because the colored paint adheres to parts other than the sphere, and a large amount of waste is generated. It was insufficient for mass production at low cost.

An object of the present invention is to eliminate the disadvantages of the prior art and to provide a method for producing colored spheres in large quantities at low cost.

[0008]

As a result of intensive studies to achieve the object of the present invention, a step of attaching a sphere to a work surface, and a step of applying a color paint to a surface of the sphere opposite to the work surface by stencil printing. It has been found that a large amount of colored spheres can be produced inexpensively by producing the spheres by using a production method having a step of coating the spheres and a step of removing the spheres from the working surface again after drying the colored paint. In other words, by attaching the sphere to the work surface, the direction in which the surface of the sphere faces can be fixed,
In this state, if the paint is applied to the surface of the sphere opposite to the working surface by stencil printing, it is possible to control the amount of coating so as not to apply a certain amount of colored paint, so the entire spherical surface is colored The coating material can be applied only in one direction of the spherical surface without the coating material turning. According to the above method, a simple and low-cost production method can be used, and continuous production is possible, so that the production amount per unit time can be increased.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The work surface (work surface on which a sphere is attached) used in the present invention can adopt various forms according to the production equipment, but is effective for efficient production. Examples of the form include a sheet shape, a plate shape, a film shape, a belt shape, a roll shape, a drum shape, and the like.

[0010] The work surface on which the spheres are attached is coated with
It is necessary that the sphere can be removed again after drying. When the sphere is a magnet, it is preferable to use a work surface having magnetism, and it is preferable that the work surface is uniformly N-pole or S-pole because the magnetic poles of the sphere have the same orientation. When the sphere is other than a magnet, the sphere is attached by suction,
A method of sticking or adhering the sphere with a means that can be separated later can be used.

In order to attach the sphere by suction, a method may be adopted in which a large number of holes are provided in the work surface, and the back surface is suctioned by a generally known suction device. When the sphere is peeled off, the suction may be stopped or the pressure may be increased.

Examples of the sticking or adhering means capable of peeling the sphere later include, for example, (i) a pressure-sensitive adhesive or adhesive having such an adhesive or adhesive strength as to enable mechanical peeling of the sphere; A substance whose adhesive strength or adhesive strength is reduced by heating, cooling, irradiation of ultraviolet rays, electron beams, or the like, or (iii) a substance which is dissolved by a solvent or a solution which does not dissolve a dried colored coating material or whose adhesive strength or adhesive strength is reduced And the like are previously provided on the surface. When an adhesive substance such as an adhesive is used, the spheres need to be brought into contact with each other at a timing at which the adhesive force can be exhibited, such as before the solvent evaporates or hardens.

As the pressure-sensitive adhesive or adhesive having the above-mentioned (i) adhesive or adhesive strength capable of mechanically peeling the sphere, a conventionally known pressure-sensitive adhesive or adhesive is used depending on the material of the sphere. I just need. It is effective to reduce the amount of the pressure-sensitive adhesive or the adhesive or to reduce the contact area in order to suppress the adhesive force or the adhesive force.

Examples of the substance (ii) whose adhesive strength or adhesive strength is reduced by heating or cooling, irradiation of ultraviolet rays or electron beams, etc. include substances which foam by heating and substances whose adhesiveness is reduced by ultraviolet rays. Can be

As a substance which is dissolved by a solvent or a solution which does not dissolve the colored paint of the above (iii) or which has reduced adhesive strength or adhesive strength, for example, when a colored paint which does not dissolve in water after drying is used, Adhesive substances such as a water-soluble resin and a water-swellable water-based emulsion resin, and substances that exhibit reversible adhesive or adhesive changes upon water swelling / drying are exemplified.

[0016] Among these, an adhesive having an adhesive strength enough to mechanically peel off the sphere, an adhesive substance soluble in a solvent or solution that does not dissolve the coloring paint, a solvent or solution that does not dissolve the coloring paint A substance whose adhesive strength or adhesive strength is reversibly changed by swelling / drying due to swelling / drying is particularly effective because the work surface or the work surface and the tacky substance or the adhesive substance can be used repeatedly.

In order to form the work surface by applying the above-mentioned pressure-sensitive adhesive or adhesive to the base material of the work surface, a generally known coating method can be used. Reverse roll coater, gravure coater, blade coater, air knife coater, bar coater,
Various coaters such as a rod coater and a die coater can be used.

In order to attach the sphere to the work surface, there are a method of dropping, extruding or spraying the sphere at a desired angle, and a method of bringing the work surface into contact with a place where the sphere is stored.

A simple example of attaching a sphere to a work surface is as follows. That is, the work surface coated with an adhesive or an adhesive is placed facing upward, and the sphere is dropped and adhered from above to sprinkle the sphere. When the sphere rides on the work surface in a single layer or more, the surplus sphere not adhering to the adhesive or the adhesive can be dropped and removed by slightly vibrating the work surface from side to side. If an adhesive containing a solvent is used, it is further dried with a drier or the like.

FIGS. 1A and 1B are cross-sectional views showing one example of these steps for continuously attaching a sphere to a work surface. 1 is a work surface, 2 is a sphere, 3 is a backup roll, 4 is a sphere supply port, 5 is a blade, and 6 is an ink pan. FIG. 1A shows a case where the sphere 2 is dropped obliquely from the inclined sphere supply port 4 and adheres to the work surface 1 running along the backup roll 3. The sphere that has fallen without performing is returned to the sphere supply port 4. In this case, the spheres 2 are more likely to adhere to the work surface 1 when the work surface 1 is run obliquely upward from the lower side as shown in the figure. FIG. 1B shows a state in which a flexible or flexible blade 5 is provided at the tip of the sphere supply port 4.
A case in which a sphere falling from the surface is guided and attached to the work surface 1 by the blade 5 is shown. Work surface 1 in this case
Is designed to run obliquely from the upper side to the lower side, contrary to the case of (a). FIG. 1C shows a state in which the spheres 2 are accommodated in the ink pan 6, the backup roll 3 is arranged at a position where the spheres 2 can come into contact with the spheres 2, and the work surface 1 is run along the backup roll 3. 2 shows a case where the sphere 2 is attached to the work surface 1. In the above example, a continuous film-shaped / belt-shaped work surface substrate is used, but a sphere can be attached to a substrate of another shape in a similar manner.

The colored paint used for coloring may be any paint having a desired color when the sphere is a magnet ball. On the other hand, when it is desired to impart electrical and magnetic properties by coating, it is necessary to use a paint that exhibits those properties.

A method of applying a colored paint to the surface of the sphere opposite to the working surface by stencil printing may be any mechanism that exudes the paint from a large number of fine holes and transfers the paint to the sphere. The typical thing is screen printing. Further, the device may not be included in the category of “printing machine” as long as the device has the same mechanism. In the case of the present invention, the colored paint may be uniformly exuded over the entire area where the sphere is attached. The form of the microporous surface of the screen or the like can be selected as required, such as a plane shape, a cylindrical shape, and a semicircular shape.

When a magnetic paint is used as the coloring paint and magnetism is imparted to the sphere, it is preferable to magnetize the sphere after applying and drying the coloring paint and before peeling the sphere from the work surface. This makes it possible to align the central axis of the coating surface and the magnetization axis in parallel or at a desired angle.

[0024]

EXAMPLES The present invention will be described in detail with reference to the following examples, which are intended to specifically explain the effects of the present invention, and do not limit the present invention.

<Example 1> [Materials] * Work surface substrate: PET film having a thickness of 100 μm * Sphere: Tuftic AR650LX- manufactured by Toyobo Co., Ltd.
W (white crosslinked acrylic fine particles with an average particle diameter of 130 μm) * Paint applied to spheres: metallic iron magnetic component (DM-86, manufactured by Dowa Mining Co., Ltd.) and vinyl chloride / vinyl acetate / vinyl alcohol copolymer (MR- 110, manufactured by Nippon Zeon Co., Ltd.) * A paint for forming a working surface and a sphere release coating: a 5% by weight aqueous solution of Poval PVA-205 (polyvinyl alcohol) manufactured by Kuraray Co., Ltd.

Using the above materials, colored spheres were produced through the following steps.

[Step] (1) Adhesive work surface forming step: The above polyvinyl alcohol aqueous solution is applied to the sheet-like work surface base material using a bar coater # 44, and a dry thickness of about 5 μm is applied to one side of the base material. A work surface was formed.

(2) Step of attaching sphere to work surface:
Before the polyvinyl alcohol aqueous solution was completely dried, the spheres were dropped from above the working surface using a sieve, and a substantially uniform single-layer sphere-adhered layer could be formed. Thereafter, it was sufficiently dried with hot air.

(3) Step of coating the sphere with a paint: The one obtained in the above (2) (work surface base material having the sphere adhered to the work surface) is set on a screen printing machine, and the surface of the sphere is set. The above paint was applied in the same procedure as in ordinary printing. Then, it was taken out of the printing press and dried with hot air.

(4) Step of peeling the sphere from the work surface:
The sphere obtained from the above (3) (work surface base material obtained by applying a colored paint to the surface of a sphere adhered to the work surface) is immersed in water to dissolve poval, and the sphere is peeled from the work surface. Let it go. The separated spheres were collected with a filter. Further, the work surface base material from which the spheres were peeled could be reused in this step.

Through the above steps, a large amount of white resin spheres partially coated with a black magnetic paint could be produced by a low-cost coating method.

[0032]

As described above, according to the present invention, a large amount of colored spheres whose surfaces are partially colored can be produced at low cost.

[Brief description of the drawings]

FIG. 1 shows an example of a process of attaching a sphere to a work surface according to the present invention, wherein (a) shows a case where the sphere is dropped obliquely, (b) shows a case where the sphere is contacted diagonally, and (c) FIG. 4 is a process diagram showing a case where a work surface is brought into contact with an ink pan containing a sphere.

[Explanation of symbols]

 Reference Signs List 1 work surface 1a work surface base material 2 sphere 3 backup roll 4 sphere supply port 5 blade 6 ink pan

Continued on front page F-term (reference) 4D075 AC45 AC71 AC78 AC93 BB24Z DA11 DA31 DB31 DB43 DC18 DC24 EB15 EB19 EC01 EC11

Claims (2)

[Claims] 1. A method for producing a colored sphere by partially applying a color to the surface thereof, comprising the steps of: adhering the sphere to a work surface; and applying a color paint to the surface of the sphere opposite to the work surface by stencil printing. And a step of peeling the sphere from the working surface again after drying the colored paint. 2. The method for producing a colored sphere according to claim 1, wherein the stencil printing is screen printing.