JP7681832B2 - Molding method - Google Patents

Description

This disclosure relates generally to molding methods, and more specifically to molding methods for processing resin sheets.

Conventionally, methods of heating and molding a resin sheet are known. The method of manufacturing a container-shaped molded product described in Patent Document 1 involves heating a sheet material (resin sheet) made of a heat-meltable fluororesin and then vacuum-molding or vacuum-pressure molding into a predetermined container or box shape.

JP 2009-214412 A

The purpose of this disclosure is to provide a molding method that can easily process the surface of a resin sheet.

A molding method according to one aspect of the present disclosure is a molding method for a thermoforming sheet. The thermoforming sheet includes a thermoplastic resin sheet. The thermoforming sheet is a color-coded sheet including a plurality of regions, each having a different color, on the surface of the resin sheet. The molding method includes a heating step and a molding step. The heating step is a step of heating the color-coded sheet by irradiating it with light. The molding step is a step of pressing the color-coded sheet against a mold and processing it into a shape that conforms to the mold. In the molding method, in the heating step, unevenness is generated on the surface of the resin sheet due to differences in light absorptance of the plurality of regions.

The present disclosure has the advantage that the surface of the resin sheet can be easily processed.

FIG. 1 is a flow chart showing a molding method according to one embodiment. FIG. 2 is a perspective view of a resin sheet used as a material in the above molding method. FIG. 3 is a perspective view of a color-coded sheet produced from the resin sheet in the above molding method. FIG. 4 is a cross-sectional view of a color-coded sheet and two molds in the above molding method. FIG. 5 is a cross-sectional view of a color-coded sheet and two molds in the above molding method. FIG. 6 is a front view of the main body of a urinal manufactured by the above molding method.

The molding method according to the embodiment will be described below with reference to the drawings. However, the embodiment described below is merely one of the various embodiments of the present disclosure. The embodiment described below can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. In addition, each figure described in the embodiment described below is a schematic diagram, and the ratio of the size and thickness of each component in the figure does not necessarily reflect the actual dimensional ratio.

(1) Overview The molding method of this embodiment is a method of molding a resin sheet 2 (see FIG. 2) into a desired shape by sheet blow molding. In addition, in the molding method of this embodiment, the resin sheet 2 is molded into a desired shape, and unevenness is also formed on the surface 21 (see FIG. 2) of the resin sheet 2. Then, a pattern, letters, or the like becomes visible to a person due to shadows generated by the unevenness.

More specifically, as shown in Figs. 1 to 3, the molding method of this embodiment is a molding method for a thermoforming sheet. The thermoforming sheet includes a thermoplastic resin sheet 2. The thermoforming sheet is a color-coded sheet 1 that includes a plurality of regions, each of which has a different color, on the surface 21 of the resin sheet 2. The molding method includes a heating step (step ST1) and a molding step (steps ST3 to ST8). The heating step is a step in which the color-coded sheet 1 is heated by irradiating it with light. The molding step is a step in which the color-coded sheet 1 is pressed against a mold 5 (see Figs. 4 and 5) and processed into a shape that conforms to the mold 5.

When light is irradiated onto the color-coded sheet 1, differences in the light absorption rate of the multiple regions cause differences in the molding temperature for each region. As a result, the thickness of the resin sheet 2 differs from region to region, resulting in unevenness on the surface 21.

The molding method of this embodiment allows the surface 21 of the resin sheet 2 to be easily processed, thereby allowing patterns or letters, etc. to be applied to the surface 21 using uneven surfaces. In this way, the above molding method allows designs to be easily applied to the surface 21.

In addition, by changing the color applied to the surface 21, the molding temperature can be adjusted, and the thickness of each area of the resin sheet 2 can be freely controlled.

(2) Details The molding method of this embodiment will be described in more detail below.

In this embodiment, an example will be described in which a lattice pattern is applied by coloring to the surface 21 of the resin sheet 2 before it is heated (see FIG. 3). Then, when the resin sheet 2 is heated and stretched, the pattern is changed to a distorted lattice-like pattern consisting of projections and recesses (see FIG. 6). As a result, people can not only see the pattern by its color, but also by the shadows cast by the projections and recesses. Furthermore, people can still see the pattern even if the color applied by coloring is removed.

In addition, in this embodiment, an example will be described in which the main body 8 of a men's urinal (see Figure 6) is manufactured by molding a resin sheet 2.

The molding method may further include a coloring step in addition to the heating step and molding step described above. The coloring step is a step for forming the color-coded sheet 1 from the resin sheet 2. The coloring step is a step for coloring at least a part of the surface 21 of the resin sheet 2 so that the color varies from region to region in the surface 21.

2 illustrates the resin sheet 2 before the coloring process. The material of the resin sheet 2 is, for example, ASA (acrylate styrene acrylonitrile) resin. The surface 21 of the resin sheet 2 is flat. The color of the surface 21 is, for example, a white-based color. By coloring a part of the surface 21 in a black-based color, the surface 21 is colored into a white-based color and a black-based color as shown in FIG. 3. In other words, the surface 21 is colored into the color of the resin sheet 2 itself and a color darker than the color of the resin sheet 2 itself. Hereinafter, the region R1 of the surface 21 that is colored in the coloring process (or the region that is colored later in the coloring process) is referred to as the "colored region," and the other region R2 is referred to as the "non-colored region." The colored region is a lattice-shaped region. The non-colored region is a collection of multiple rectangular sections arranged in a matrix.

The coloring process of this embodiment includes a process of applying a black-based paint in a grid pattern to the surface 21 of the resin sheet 2 by a printing method. In other words, a member including at least the resin sheet 2 and the paint applied to the surface 21 of the resin sheet 2 is the color-coded sheet 1. In this way, the coloring process preferably includes a process of coloring at least a portion (colored area) of the surface 21 of the resin sheet 2 by a printing method. By using a printing method, the surface 21 of the resin sheet 2 can be easily colored into various patterns and character shapes. The printing method is preferably, for example, a screen printing method.

The multiple regions on the surface 21 of the resin sheet 2, each of which is a different color, include the above-mentioned colored regions and non-colored regions. In other words, the multiple regions include white-based regions (non-colored regions), which are the color of the resin sheet 2 itself. Furthermore, the multiple regions include black-based regions (colored regions).

At least one of the multiple regions (colored region) forms a repeating pattern. In other words, a repeating pattern is formed on the surface 21 of the resin sheet 2 by color coding. More specifically, at least one of the multiple regions (colored region) forms a lattice pattern. A repeating pattern is a pattern (figure) in which a specific shape appears repeatedly in a certain direction in a regular pattern.

Next, the heating process will be described. The heating process is a process in which the surface of the color-coded sheet 1 is heated by irradiating the color-coded sheet 1 with light. The resin sheet 2 becomes soft by heating, making it easier to shape in the molding process. The heating process is carried out, for example, before the molding process. The heating process may also be carried out, for example, during the molding process.

The heating process includes a process of irradiating light (infrared rays) from an infrared heater to the color-coded sheet 1. Examples of infrared heaters are halogen heaters and carbon heaters. The light irradiated from the infrared heater to the color-coded sheet 1 in the heating process is preferably far-infrared rays. In this case, the light is easily absorbed by the resin that constitutes the resin sheet 2.

When light is irradiated onto the color-coded sheet 1, differences in the light absorptance of the multiple regions cause differences in temperature between the regions. Specifically, the black-colored regions have a higher light absorptance than the white-colored non-colored regions, and therefore have a higher temperature.

The temperature difference between the different regions causes unevenness on the surface 21 of the resin sheet 2. That is, in areas where the light absorptance is relatively high, the temperature rise is large, so that the corresponding areas of the resin sheet 2 are significantly deformed and recessed. On the other hand, in areas where the light absorptance is relatively low, the temperature rise is small, so that the deformation amount of the corresponding areas of the resin sheet 2 is small. As a result, the areas where the light absorptance is relatively high are recessed more than the areas where the light absorptance is relatively low. Specifically, the black-colored areas are recessed more than the white-colored non-colored areas.

Next, the molding process will be described. In the molding process, the color-coded sheet 1 is processed so that the colored surface 21 of the resin sheet 2 becomes the front surface of the urinal body 8 (see Figure 6). The molding process includes a blowing process and a vacuuming process.

In the molding process of this embodiment, the color-coded sheet 1 is molded by the plug assist method. As shown in Figures 4 and 5, multiple (two) molds 5 are used in the molding process. The multiple molds 5 include a lower mold 6 and a plug 7. The lower mold 6 has a recess 61 into which at least a portion of the color-coded sheet 1 is inserted. The plug 7 can be inserted into the recess 61 so as to sandwich the color-coded sheet 1 between the plug 7 and the bottom surface of the recess 61. The plug 7 is positioned above the lower mold 6.

Prior to the molding process, a heating process is carried out (step ST1). In the heating process, the color-coded sheet 1 held by the clamp is heated and softened. After that, the color-coded sheet 1 is placed between the lower mold 6 and the plug 7 while still being held by the clamp (step ST2) (see FIG. 4).

Next, the blowing process is started (step ST3). In the blowing process, air is blown onto the color-coded sheet 1. That is, air is blown onto the color-coded sheet 1, stretching it. The air is blown up from below. The color-coded sheet 1 is deformed so that it covers the plug 7.

The plug 7 is then inserted into the recess 61 of the lower die 6 while pressing the color-coded sheet 1 (step ST4) (see FIG. 5). The plug 7 presses the color-coded sheet 1 against the lower die 6, adjusting the shape of the color-coded sheet 1. The blowing process is also performed at this time, so that the color-coded sheet 1 is pressed against the plug 7 by air, and is molded into a shape that matches the plug 7.

Next, the lower mold 6 is raised (step ST5). In parallel with raising the lower mold 6, a vacuuming process is carried out (step ST6). In the vacuuming process, air is sucked out from between the color-coded sheet 1 and the lower mold 6 through multiple holes provided in the lower mold 6, and the color-coded sheet 1 is brought into close contact with the lower mold 6.

Next, the color-coded sheet 1 is cooled and solidified (step ST7). Furthermore, the color-coded sheet 1 is released from the lower mold 6 (step ST8). After that, the processing of the color-coded sheet 1 is completed through processes such as deburring. In other words, a molded product (the urinal body 8) is manufactured using the color-coded sheet 1 as the material (see Figure 6).

Thus, in the molding method of this embodiment, the molding process includes a process of pressing the color-coded sheet 1 against the mold 5 by air blowing. The molding process also includes a process of sucking the color-coded sheet 1 into the mold 5 by vacuum drawing.

(Modification of the embodiment)
Modifications of the embodiment will be listed below. The following modifications may be implemented in appropriate combination.

The article manufactured by the molding method of the present disclosure is not limited to the urinal body 8. For example, containers, pipes, baskets, etc. may be manufactured by the molding method of the present disclosure.

In the coloring step, instead of the screen printing as the printing method, at least a part (colored area) of the surface 21 of the resin sheet 2 may be colored by inkjet printing. In addition, instead of the printing method, in the coloring step, the surface 21 may be colored by, for example, fixing a colored member (tape or cloth, etc.) to the surface 21 of the resin sheet 2, or by using a pen. In particular, it is preferable that the surface 21 is colored by fixing a sealant that can be peeled off after molding of the resin sheet 2 to the surface 21. In this case, by removing the sealant, a molded product without added color can be manufactured. The surface 21 may also be colored by ink or the like that can be removed by washing, etc.

The grid pattern on the surface 21 of the resin sheet 2 may be a pattern in which the positions of the colored areas (black areas) and the positions of the non-colored areas (white areas) are interchanged compared to the embodiment.

The surface 21 of the resin sheet 2 may be color-coded to form an irregular pattern instead of a repeating pattern.

The repeating pattern is not limited to a lattice pattern. The repeating pattern may be, for example, a honeycomb pattern. Alternatively, the repeating pattern may be, for example, a pattern in which triangles or parallelograms are closely packed together (plane tessellation). Alternatively, the repeating pattern may be a pattern created by repeatedly arranging a certain pattern.

The color coding of the surface 21 of the resin sheet 2 is not limited to white-based and black-based colors. For example, the surface 21 may be color coded using colors of red, blue, or green. The surface 21 may also be color coded using more than two colors.

In the coloring process, a pattern or the like may be applied only to a portion of the surface 21 of the resin sheet 2.

The flowchart shown in FIG. 1 is merely one example of the molding method according to the present disclosure, and the order of the steps may be changed as appropriate, and steps may be added or omitted as appropriate.

(summary)
The above-described embodiments and the like disclose the following aspects.

The molding method according to the first aspect is a molding method for a thermoforming sheet. The thermoforming sheet includes a thermoplastic resin sheet (2). The thermoforming sheet is a color-coded sheet (1) including a plurality of regions, each of which has a different color, on the surface (21) of the resin sheet (2). The molding method includes a heating step (step ST1) and a molding step (steps ST3 to ST8). The heating step is a step of heating the color-coded sheet (1) by irradiating it with light. The molding step is a step of pressing the color-coded sheet (1) against a mold (5) and processing it into a shape that fits the mold (5).

According to the above configuration, the degree of temperature rise in the heating process differs in the multiple regions depending on the difference in color (light absorptivity) of the surface (21) of the resin sheet (2). As a result, after the heating process is completed, the properties of the surface (21) of the resin sheet (2) change. For example, one of the multiple regions on the surface (21) of the resin sheet (2) becomes more recessed than another region. In this way, according to the above molding method, the surface (21) of the resin sheet (2) can be easily processed.

The molding method according to the second aspect further includes a coloring step as a step for forming the color-coded sheet (1) from the resin sheet (2) in the first aspect. The coloring step is a step of coloring at least a part of the surface (21) of the resin sheet (2) so that the color varies from region to region in the surface (21).

The above configuration allows for the provision of a color-coded sheet (1).

In addition, in the molding method according to the third aspect, in the second aspect, the coloring step includes a step of coloring at least a portion of the surface (21) by a printing method.

According to the above configuration, the surface (21) of the resin sheet (2) can be easily colored with various patterns and letter shapes by using a printing method.

In addition, in the molding method according to the fourth aspect, in any one of the first to third aspects, the heating step includes a step of irradiating the color-coded sheet (1) with infrared rays from an infrared heater.

The above configuration allows the color-coded sheet (1) to be locally heated.

In addition, in the molding method according to the fifth aspect, in any one of the first to fourth aspects, the multiple regions include white regions, which is the color of the resin sheet (2) itself.

With the above configuration, there is no need to color the areas that are to be left as white areas, so the amount of ink, etc. used for coloring can be reduced.

In addition, in the molding method according to the sixth aspect, in any one of the first to fifth aspects, the multiple regions include a black-colored region.

According to the above configuration, it is particularly easy to increase the temperature in the black-colored areas during the heating process. Therefore, the black-colored areas can be efficiently heated by the heating process.

In addition, in the molding method according to the seventh aspect, in any one of the first to sixth aspects, at least one of the multiple areas forms a repeating pattern.

The above configuration reduces the effort required to color at least a portion of the above area.

In addition, in the molding method according to the eighth aspect, in the seventh aspect, at least one of the multiple areas forms a lattice pattern.

The above configuration makes it easy to form tile-like resin molded products.

In addition, in the molding method according to the ninth aspect, in any one of the first to eighth aspects, the molding step includes a step of pressing the color-coded sheet (1) against the mold (5) by air blowing.

According to the above configuration, the color-coded sheet (1) can be attached closely to the mold (5). This reduces distortion of the resin sheet (2). In addition, distortion of the pattern on the surface (21) of the resin sheet (2) can be reduced.

In addition, in the molding method according to the tenth aspect, in any one of the first to ninth aspects, the molding step includes a step of sucking the color-coded sheet (1) into the mold (5) by vacuum drawing.

According to the above configuration, the color-coded sheet (1) can be attached closely to the mold (5). This reduces distortion of the resin sheet (2). In addition, distortion of the pattern on the surface (21) of the resin sheet (2) can be reduced.

Configurations other than the first aspect are not essential to the molding method and can be omitted as appropriate.

1. Color-coded sheet (thermoforming sheet)
2 Resin sheet 5 Mold 21 Surface ST1 Step (heating process)
ST3 to ST8 steps (molding process)

Claims (10)

A molding method for a thermoforming sheet, comprising the steps of:
The thermoforming sheet includes a thermoplastic resin sheet, and the surface of the resin sheet is a color-coded sheet including a plurality of regions each having a different color,
The molding method includes:
a heating step of heating the color-coded sheet by light irradiation;
A molding process of pressing the color-coded sheet against a mold and processing it into a shape that conforms to the mold ,
In the heating step, unevenness is generated on the surface of the resin sheet due to differences in light absorptance of the plurality of regions.
Molding method. As a process for forming the color-coded sheet from the resin sheet,
The method further includes a coloring step of coloring at least a portion of the surface of the resin sheet such that the plurality of regions on the surface have different colors.
The molding method according to claim 1. The coloring step includes a step of coloring at least the portion of the surface by a printing method.
The molding method according to claim 2. The heating step includes a step of irradiating the color-coded sheet with infrared rays from an infrared heater.
The molding method according to any one of claims 1 to 3. The plurality of regions includes a white region which is the color of the resin sheet itself,
The molding method according to any one of claims 1 to 4. The plurality of regions includes a black region.
The molding method according to any one of claims 1 to 5. At least one of the plurality of regions forms a repeating pattern.
The molding method according to any one of claims 1 to 6. At least one of the plurality of regions forms a lattice pattern.
The molding method according to claim 7. The molding step includes a step of pressing the color-coded sheet against the mold by air blowing.
The molding method according to any one of claims 1 to 8. The molding step includes a step of sucking the color-coded sheet into the mold by vacuum suction.
The molding method according to any one of claims 1 to 9.

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