This application claims the benefit of Japanese Patent Application No. 2018-239100, filed on Dec. 21, 2018, the entire disclosure of which is incorporated by reference herein.
The present disclosure relates to a molding sheet, a manufacturing method of the molding sheet, and a manufacturing method of a shaped object.
Technology is known, such as in Examined Japanese Patent Application Publication No. S59-35359, that, after forming an image from a material having high light absorbance on a surface of a thermally expandable sheet including thermally expandable microspheres (thermal expansion material), then manufactures a sheet, that is, a shaped object, forming a three-dimensional image by irradiation of the thermally expandable sheet with light and causing swelling by selective heating of an image portion.
Per the description in Examined Japanese Patent Application Publication No. S59-35359, height of a swollen portion, that is, a convexity, is controlled by a density (or concentration) of the image formed on the surface of the thermally expandable sheet. When the thermally expandable microspheres (thermal expansion material) formed by microencapsulation of a low boiling-point substance with a thermoplastic resin are heated to a temperature higher than a maximum expansion temperature, that is, a temperature at which particle size becomes maximum, the microcapsules shrink relative to the maximum particle size. Therefore, when a difference between a temperature of heating by a dense portion of the image and the maximum expansion temperature of the thermal expansion material is small, the thermal expansion material is heated to a temperature higher than the maximum expansion temperature so that the thermal expansion material shrinks, and such shrinkage may lower the height of the convexity below a desired height.
A high convexity cannot be formed when the image is formed lightly in order to avoid heating the thermal expansion material to a temperature higher than the maximum expansion temperature. However, when a thermally expandable sheet is prepared with a thermal expansion material that has a higher maximum particle size and a higher maximum expansion temperature, an expansion initiation temperature (temperature at which expansion of the thermal expansion material starts), is high, and the range of the density of the image for control of the height of the convexity narrows.
In consideration of the aforementioned circumstances, an objective of the present disclosure is to provide a molding sheet, a manufacturing method of the molding sheet, and a manufacturing method of the shaped object such that height of a convexity of the manufactured shaped object is easily controlled. Moreover, another objective of the present disclosure is to provide a molding sheet, a manufacturing method of the molding sheet, and a manufacturing method of the shaped object that enable increasing height of the convexity of the manufactured shaped object.
In order to achieve the aforementioned objectives, a molding sheet according to a first aspect of the present disclosure includes a base and a thermal expansion layer laminated onto a first main surface of the base. The thermal expansion layer includes a first thermal expansion material and a second thermal expansion material. A maximum expansion temperature of the second thermal expansion material is higher than a maximum expansion temperature of the first thermal expansion material.
In order to achieve the aforementioned objectives, a manufacturing method, of a molding sheet for manufacturing a shaped object by expansion of at least a portion of a thermal expansion layer arranged on one surface of a base, is a manufacturing method including a step of forming the thermal expansion layer on the one surface of the base. The first thermal expansion material and a second thermal expansion material are used in the step of forming the thermal expansion layer. A maximum expansion temperature of the second thermal expansion material is higher than a maximum expansion temperature of the first thermal expansion material.
In order to achieve the aforementioned objectives, a manufacturing method of a shaped object according to a third aspect of the present disclosure is a manufacturing method of a shaped object using a molding sheet including a base and a thermal expansion layer arranged on one surface of the base. The thermal expansion layer includes a first thermal expansion material and a second thermal expansion material. A maximum expansion temperature of the second thermal expansion material is higher than a maximum expansion temperature of the first thermal expansion material. The manufacturing method includes: laminating onto one surface of the molding sheet a thermal conversion layer for conversion of electromagnetic waves into heat, and irradiating the thermal conversion layer with the electromagnetic waves to expand the thermal expansion layer.
A more complete understanding of this application can be obtained when the following detailed description is considered in conjunction with the following drawings, in which:
A molding sheet according to an embodiment of the present disclosure is described below with reference to drawings.
A molding sheet 10 of the present embodiment is used in the manufacture of a shaped object 100. The shaped object 100 is used is used for decorative sheeting, wallpaper, or the like. In the present disclosure, the term “shaped object” refers to a sheet that includes unevennesses shaped (formed) on a predetermined surface, and the unevennesses form geometrical shapes, characters, patterns, decorations, or the like. The term “decorations” refers to objects that appeal to the aesthetic sense through visual and/or tactile sensation. The term “shaped (or molded)” refers to the forming of an object that has a shape, and is to be construed to also include concepts such as decoration and ornamentation by forming decorations. Moreover, although the shaped object 100 of the present embodiment is a three-dimensional object that includes unevennesses on a predetermined surface, to distinguish this three-dimensional object from three-dimensional objects formed using a so-called 3D printer, the shaped object 100 of the present embodiment is called a 2.5-dimensional (2.5D) object or a pseudo-three-dimensional (pseudo-3D) object. The technique used to manufacture the shaped object 100 of the present embodiment is called 2.5D printing or pseudo-3D printing.
Molding Sheet
The molding sheet 10 is firstly described with reference to
The base 20 of the molding sheet 10 has a first main surface 22 onto which the thermal expansion layer 30 is laminated and a second main surface 24 on the side opposite to the first main surface 22. The base 20 supports the thermal expansion layer 30. The base 20 is formed, for example, in a sheet-like shape. Examples of the material of the base 20 include thermoplastic resins such as polyolefin resins (polyethylene (PE), polypropylene (PP), or the like) and polyester resins (polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or the like). The type of material of the base 20 and the thickness of the base 20 are selected according to the intended application of the shaped object 100.
The thermal expansion layer 30 of the molding sheet 10 includes a binder 31, and a first thermal expansion material 32a and a second thermal expansion material 33a dispersed in the binder 31. In the present embodiment, the weight ratio of the binder 31 to the first thermal expansion material 32a to the second thermal expansion material 33a is 2:1:1, that is, the ratio of the weight of the total of the first thermal expansion material 32a and the second thermal expansion material 33a to the weight of the binder 31 is 1:1.
Any thermoplastic resin, such as a vinyl acetate-type polymer or an acrylic-type polymer, may be used as the binder 31. The first thermal expansion material 32a and the second thermal expansion material 33a are thermally expandable microcapsules, for example. The thermally expandable microcapsules are microcapsules that encapsulate a foaming agent including propane, butane, or another low boiling point substance in shells made from a thermoplastic resin. The shells of the thermally expandable microcapsules are formed from a thermoplastic resin such as, for example, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid ester, polyacrylonitrile, polybutadiene, and copolymers thereof.
As illustrated in
Similarly to the first thermal expansion material 32a, upon heating to a temperature greater than or equal to the expansion initiation temperature Ts2 and less than or equal to the maximum expansion temperature Tm2, the second thermal expansion material 33a expands to a state in which the particle size is a certain particle size corresponding to the temperature of heating. Upon heating to a temperature higher than the maximum expansion temperature Tm2, after expansion up to the state in which the particle size is maximum, the second thermal expansion material 33a shrinks down to a state in which the particle size corresponds to the temperature of heating. In the present embodiment, the maximum expansion temperature Tm2 of the second thermal expansion material 33a is higher than the maximum expansion temperature Tm1 of the first thermal expansion material 32a. The expansion initiation temperature Ts2 of the second thermal expansion material 33a is higher than the expansion initiation temperature Ts1 of the first thermal expansion material 32a and is lower than the maximum expansion temperature Tm1 of the first thermal expansion material 32a. Specifically, the average particle size of the second thermal expansion material 33a is 12 μm to 18 μm, for example. The expansion initiation temperature Ts2 of the second thermal expansion material 33a is 105° C. to 115° C., and the maximum expansion temperature Tm2 is 145° C. to 155° C., for example. Moreover, the maximum particle size of the second thermal expansion material 33a is larger than the maximum particle size of the first thermal expansion material 32a.
The thermal expansion layer 30 of the molding sheet 10 expands due to expansion of the first thermal expansion material 32a and the second thermal expansion material 33a. Due to expansion of the thermal expansion layer 30, a below-described convexity 110 is formed on a surface 35 that is at the side opposite to the base 20 side.
Manufacturing Method of Molding Sheet
In the mixing step (step S11), the base 20, the binder 31, the first thermal expansion material 32a, and the second thermal expansion material 33a are prepared. Thereafter, the mixed liquid for forming the thermal expansion layer 30 is formed by mixing together of the binder 31, the first thermal expansion material 32a, and the second thermal expansion material 33a.
In the coating step (step S12), a coating device is used to coat the prepared mixed liquid onto the first main surface 22 of the base 20. The coating device is a device such as a bar coater, a roll coater, a spray coater, or the like.
In the drying step (step S13), the mixed liquid coated upon the first main surface 22 of the base 20 is dried. Due to such operation, the thermal expansion layer 30 is formed on the first main surface 22 of the base 20. The molding sheet 10 is manufactured in the above-described manner. The coating step (step S12) and the drying step (step S13) may be repeatedly performed in order to obtain a prescribed thickness of the thermal expansion layer 30.
Shaped Object
Manufacture of the shaped object 100 from the molding sheet 10 is described next with reference to
The shaped object 100 is a sheet-like shaped object. The shaped object 100 has unevenness due to the convexity 110 on the surface. The configuration of the base 20 of the shaped object 100 is similar to configuration of the base 20 of the molding sheet 10, and thus the thermal expansion layer 30 and the thermal conversion layer 130 of the shaped object 100 are described below.
As illustrated in
A thermal conversion layer 130 of the shaped object 100 includes a thermal conversion material. The thermal conversion layer 130 is provided in order to form the convexity 110 on the thermal expansion layer 30. The thermal conversion layer 130 is laminated onto the thermal expansion layer 30 in a pattern corresponding to the convexity 110. The thermal conversion layer 130 converts irradiated electromagnetic waves to heat and releases the converted heat. Such operation heats the thermal expansion layer 30 of the molding sheet 10, expands the first thermal expansion material 32a and the second thermal expansion material 33a, and forms the convexity 110 on the thermal expansion layer 30. The height h of the formed convexity 110 depends on a heat amount, that is, thermal energy, imparted to the thermal expansion layer 30, that is, the first thermal expansion material 32a and the second thermal expansion material 33a. In the present embodiment as described below, the height h of the convexity 110 is controlled by control of the heat amount imparted to the thermal expansion layer 30 in accordance with a density of the thermal conversion layer 130.
The thermal conversion material included in the thermal conversion layer 130 converts the absorbed electromagnetic waves to heat. Examples of the thermal conversion material include carbon black, metal hexaboride compounds, and tungsten oxide compounds. Carbon black, for example, absorbs and converts visible light, infrared light, or the like to heat. Metal hexaboride compounds and tungsten oxide compounds absorb and convert near-infrared light to heat. Among the metal hexaboride compounds and the tungsten oxide compounds, lanthanum hexaboride (LaB6) and cesium tungsten oxide are preferably used from the perspectives of obtaining high light absorptivity in the near-infrared region and high transmittance in the visible light spectrum.
Manufacturing Method of Shaped Object
The manufacturing method of the shaped object 100 is described next with reference to
In the thermal conversion layer laminating step (step S20), a printing device prints an ink including the thermal conversion material onto the thermal expansion layer 30 of the molding sheet 10 in a pattern corresponding to the convexity 110. Due to such operation, as illustrated in
In the expansion step (step S30), the thermal conversion layer 130 is irradiated with the electromagnetic waves having a prescribed energy, while moving at a prescribed speed at least one of the molding sheet 10 onto which the thermal conversion layer 130 is laminated or a non-illustrated irradiation unit for irradiating the thermal conversion layer 130 with the electromagnetic waves. The thermal conversion layer 130 converts the irradiated electromagnetic waves to heat and releases the converted heat. In the present embodiment, the first thermal expansion material 32a and the second thermal expansion material 33a expand due to the heat released from the thermal conversion layer 130 to form the expanded first thermal expansion material 32b and the expanded second thermal expansion material 33b. Due to such operation, the thermal expansion layer 30 expands and thus forms the convexity 110. The shaped object 100 can be manufactured by the above-described operation.
Height of Convexity
Here, the height h of the convexity 110 of the thermal expansion layer 30 and the density of the thermal conversion layer 130 are described with reference to
Moreover, the density of the thermal conversion layer 130 is controlled by a dot density, that is, by the density of the thermal conversion material, printed in the thermal conversion layer laminating step (step S20). In the present embodiment, the density occurring in the state in which the thermal conversion layer 130 is printed at a maximum dot density is taken to be a density value of the thermal conversion layer equal to “100”. In the expansion step (step S30), due to irradiation of the thermal conversion layer 130 with the electromagnetic waves having a prescribed (fixed) energy, the density of the thermal conversion layer 130 is proportional to the heat amount imparted to the thermal expansion layer 30.
As illustrated in
As illustrated in
Furthermore, the maximum value of height of the convexity 110 is larger for the molding sheet 10 of the present embodiment in comparison to the Comparative Examples 1 and 2. Therefore, the molding sheet 10 can increase the height h of the convexity 110.
In the aforementioned manner, due to the thermal expansion layer 30 including the first thermal expansion material 32a having the maximum expansion temperature Tm1 and the second thermal expansion material 33a having the maximum expansion temperature Tm2 that is higher than the maximum expansion temperature Tm1, the molding sheet 10 can control the height h of the convexity 110 in the region in which the heat amount imparted to the thermal expansion layer 30 is high. The molding sheet 10 can control the height h of the convexity 110 even in the region in which a low heat amount is imparted to the thermal expansion layer 30. Therefore, for a wider range of the heat amount imparted to the thermal expansion layer 30, the molding sheet 10 can control the height h of the convexity 110 and can easily control the height h of the convexity 110. Further, the molding sheet 10 can further increase the height h of the convexity 110.
Moreover, as illustrated in
Although embodiments of the present disclosure are described above, various types of modifications are possible for the present disclosure within a scope that does not depart from the gist of the present disclosure.
For example, the shaped object 100 may be manufactured in a roll shape from a roll-like molding sheet 10.
The material included in the base 20 is not limited to thermoplastic resins. The material included in the base 20 may be paper, fabric, or the like. The thermoplastic resin included in the base 20 is not limited to polyolefin resins and polyester resins. The thermoplastic resin included in the base 20 may be a polyamide resin, a polyvinyl chloride (PVC) resin, a polyimide resin, or the like.
The ratio of the total of the weight amounts of the first thermal expansion material 32a and the second thermal expansion material 33a to the weight amount of the binder 31 is not limited to 1:1. From the standpoint of stability of the shape of the convexity 110, the ratio of the total of the weight amounts of the first thermal expansion material 32a and the second thermal expansion material 33a to the weight amount of the binder 31 is preferably 9:1 to 1:1. Moreover, the weight ratio of the first thermal expansion material 32a to the second thermal expansion material 33a is not limited to 1:1. The weight ratio of the first thermal expansion material 32a to the second thermal expansion material 33a is preferably 0.2 to 4, inclusive. In the case in which the weight ratio of the second thermal expansion material 33a is less than 0.2, the settling of the convexity 110 due to shrinkage of the expanded first thermal expansion material 32b becomes greater than the swelling of the convexity 110 due to expansion of the second thermal expansion material 33a, and the height h of the convexity 110 decreases. Moreover, in the case in which the weight ratio of the second thermal expansion material 33a is larger than 4, the heat amount for starting to increase the height h of the convexity 110 increases, and the range of the heat amount for controlling the height h of the convexity 110 narrows.
Moreover, the expansion initiation temperature Ts2 of the second thermal expansion material 33a is preferably lower than the maximum expansion temperature Tm1. When the expansion initiation temperature Ts2 of the second thermal expansion material 33a is higher than the maximum expansion temperature Tm1 of the first thermal expansion material 32a, the settling of the convexity 110 due to shrinkage of the expanded first thermal expansion material 32b is greater than the swelling of the convexity 110 due to expansion of the second thermal expansion material 33a, and the height h of the convexity 110 tends to decrease. Although the maximum particle size of the second thermal expansion material 33a may be smaller than the maximum particle size of the first thermal expansion material 32a, in order to suppress the settling of the convexity 110 due to shrinkage of the expanded first thermal expansion material 32b, the maximum particle size of the second thermal expansion material 33a is preferably larger than the maximum particle size of the expanded first thermal expansion material 32b.
In addition to the first thermal expansion material 32a and the second thermal expansion material 33a, the thermal expansion layer 30 may include one additional other thermal expansion material, or may include a plurality of such other thermal expansion materials. For example, the thermal expansion layer 30 may include a thermal expansion material that has a maximum expansion temperature higher than the maximum expansion temperature Tm2 of the second thermal expansion material 33a, and has an expansion initiation temperature higher than the expansion initiation temperature Ts2 of the second thermal expansion material 33a and lower than the maximum expansion temperature Tm2.
In the embodiments, the thermal conversion layer 130 is laminated onto the thermal expansion layer 30. The thermal conversion layer 130 may be laminated onto the second main surface 24 of the base 20. Moreover, the thermal conversion layer 130 may be laminated to a release layer provided upon the thermal expansion layer 30. Due to such configuration, the release layer can be pealed away from the shaped object 100, and the thermal conversion layer 130 can be removed from the shaped object 100.
Another layer of a freely-selected material may be formed between each layer of the molding sheet 10 and the shaped object 100. For example, an adhesive layer may be formed, between the base 20 and the thermal expansion layer 30, for greater adhesion between the base 20 and the thermal expansion layer 30. The adhesive layer includes a surface modifier, for example.
Moreover, a color image may be printed onto the shaped object 100. For example, a color ink layer representing the color image and including the four colors of cyan, magenta, yellow, and black may be laminated onto the thermal expansion layer 30 of the shaped object 100.
The printing device for printing the thermal conversion layer 130 is not limited to an inkjet printer. For example, the printing device may be a laser printer.
The method of manufacture of the shaped object 100 from the molding sheet 10 is not limited to the manufacturing method of the embodiments. For example, the convexity 110 may be formed by heating the thermal expansion layer 30 by irradiating the molding sheet 10 with laser light or with irradiation light from an infrared lamp. Moreover, the convexity 110 may be formed by heating the thermal expansion layer 30 by a thermal print head on which are arrayed electrical heaters or heating resistor elements. In such manufacturing methods, the thermal conversion layer 130 is not laminated onto the molding sheet 10.
The foregoing describes some example embodiments for explanatory purposes. Although the foregoing discussion has presented specific embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of the invention is defined only by the included claims, along with the full range of equivalents to which such claims are entitled.
Number | Date | Country | Kind |
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2018-239100 | Dec 2018 | JP | national |