Description

METHOD FOR MANUFACTURING A FORM

Technical Field

[1] The present invention relates to a method of manufacturing foam, and, more particularly, to a method of manufacturing foam, which can form arbitrarily-shaped foam patterns having various material properties on a surface of the foam through only one foaming process. Background Art

[2] Recently, foam products obtained by crosslinking and foaming various resins, such as polyethylene (PE), ethylene-vinyl acetate (EVA), and the like, have been widely used in all industrial fields. These foam products have advantages in that they have low specific gravity, high elasticity and high shock-absorbing capacity, and can be formed into any desired shapes using specific molds. Accordingly, the use thereof is gradually increasing.

[3] In the case where various foam products come onto the market, when it is determined that the foam products have substantially the same function, the significant factor that stimulates customers to buy a specific product is whether or not that product has an excellent external visual appearance that differentiates it from other products. Therefore, companies that produce foam products continually make various attempts to impart visual effects that differentiate their products from other products in order to increase the competitiveness of their products.

[4] One of the most general methods of imparting visual effects to foam is a method of separately forming foam pieces having different colors or peculiar shapes, and then bonding the formed foam pieces to each other using separate adhesion means, thereby finally obtaining foam having different colors or various patterns depending on the region thereof. However, this method has a problem in that, since foam pieces having different colors or shapes depending on the region thereof must be separately manufactured, the number of expensive molds, which are tools for molding, must be increased, and thus the cost of manufacturing a single final foam product is excessively high. Further, this method has a problem in that, as the colors and patterns of foam pieces to be manufactured are various, additional processes therefor are performed, so that the productivity of the product is greatly decreased. Moreover, this method has problems in that the integrity of final foam products can be greatly decreased because the separately manufactured foam pieces must be bonded to each other using an adhesion means, and the durability of foam is decreased because the bonded surface between the individually manufactured foam pieces can be separated upon long-term

use thereof.

[5] Another of the most general methods of imparting visual effects to foam is a method of forming specific colors and patterns on a predetermined area or a whole area of the external surface of foam by coating the area of the external surface of foam to which visual effects are to be imparted, using ink, paint, or the like. However, this method has a problem in that a large number of processes for applying aqueous coating materials having high fluidity to the predetermined area of the external surface of the foam or the entire external surface of the foam must necessarily be performed, thus decreasing productivity. Moreover, this method has problems in that many inferior products may be produced depending on the level of skill due to the difficulty of performing coating work. Furthermore, even after the coating work is perfectly performed, since the coating film formed on the predetermined area of the surface of foam may be changed in color or contaminated due to careless handling or due to friction and contact between the coating film and other objects, inferior products may be additionally produced.

[6] Korean Unexamined Patent Application Publication No. 10-2002-0085143 proposes one of technologies having been made to improve the problems occurring in the prior. The publication discloses a method of manufacturing foam, in which the regions of the manufactured foam have colors and material properties different from each other, or are imparted with various patterns through only a single foaming process, by fundamentally departing from a method of manufacturing foam by individually manufacturing the foam pieces and then bonding them to each other or a method of manufacturing foam having various colors and patterns by applying coating materials on the surface thereof, which have been commonly used to impart visual effects to the foam. However, this technology is problematic in that an entire region of foam is treated to impart any region of foam with a color or material property. Thus, when only the surface of foam, rather than all of the foam, is to be treated, the process thereof is somewhat complex, and thus it is difficult to complete desired work by implementing this process.

[7]

Disclosure of Invention Technical Problem

[8] Accordingly, the present invention has been made to overcome the above problems occurring in the prior art, and an object of the present invention is to provide a method of manufacturing foam, which provides patterns having arbitrary colors, material properties, or shapes on a surface of the foam, without performing an additional adhering or coating process.

Technical Solution

[9] In order to accomplish the above object, the present invention provides a method of manufacturing foam, including the steps of preparing a body molding material having a predetermined shape, which is present in a condition of suppressing crosslinking and foaming thereof, at least one pattern molding material having a predetermined pattern, which is present in a condition of suppressing crosslinking and foaming thereof, and a cover molding material, which is present in a condition of suppressing crosslinking and foaming thereof; joining the pattern molding material to one surface of the cover molding material; placing the cover molding material, combined with the pattern molding material, and the body molding material into a mold; and simultaneously crosslinking and foaming the molding materials placed in the mold after closing the mold.

[10] The method is characterized in that the step of placing is performed using one selected from among a process of placing the cover molding material combined with the pattern molding material into the mold having a predetermined shape such that one surface of the cover molding material comes into close contact with an inner surface of the mold and then placing the body molding material in the remaining space other than a space occupied by the cover molding material in the mold, a process of placing the body molding material in a cavity of the mold having a predetermined shape and then inserting and placing the cover molding material joined with the pattern molding material in a space between the outer surface of the body molding material and the inner surface of the mold, and a method of combining another surface of the cover molding material, which is not combined with the pattern molding material, to the outer surface of the body molding material and then placing the combined molding materials into a cavity of the mold having a predetermined shape.

[11] Further, the present invention provides a method of manufacturing foam, including the steps of preparing at least one pattern molding material having a predetermined pattern, which is present in a condition of suppressing crosslinking and foaming thereof, and a cover molding material, which is present in a condition of suppressing crosslinking and foaming thereof; joining the pattern molding material to one surface of the cover molding material; placing the cover molding material joined with the pattern molding material into the mold having a predetermined shape such that one surface of the cover molding material comes into contact with an inner surface of the mold; injecting a foaming material into the remaining space other than a space occupied by the cover molding material in the mold, after closing the mold; and simultaneously crosslinking and foaming the injected foaming material and the molding materials.

[12] The method is characterized in that a plurality of pattern molding material is joined to one surface of the cover molding material. [13] The method is characterized in that the color of the pattern molding material is different from that of the cover molding material. [14] The method is characterized in that one or both of the cover molding material and the pattern molding material are the same as or different from the body molding material. [15] The method is characterized in that one or both of the cover molding material and the pattern molding material are formed to have a thin film shape. [16]

Advantageous Effects

[17] The present invention has an advantage in that a foam including a foamed surface having various patterns and colors can be realized through a single foaming process, and thus various foam products, which satisfy consumers' demands, can be produced.

[18] Further, the present invention has an advantage in that, when foam patterns are formed on the surface of a foam, no additional joining process or coating process is required, so that the process of manufacturing foam is greatly simplified, thereby producing foam products having various functions and appearances at low cost. Brief Description of the Drawings

[19] FIG. 1 is a view showing a process of joining pattern molding materials to a cover molding material;

[20] FIG. 2 is a view showing a configuration in which pattern molding materials are joined to a cover molding material shown in FIG.l;

[21] FIG. 3 is a sectional view showing the configuration of FIG. 2, taken along the line

A-A';

[22] FIG. 4 is a view showing a process of foaming molding materials using a mold according to an embodiment of the present invention;

[23] FIG. 5 is a view showing a process of foaming molding materials using a mold according to another embodiment of the present invention; and

[24] FIGS. 6 to 8 are perspective views showing various foam manufactured using a method of manufacturing foam according to the present invention.

[25] * Description of the elements in the drawings *

[26] 12 : body molding material

[27] 14 : cover molding material

[28] 16 : pattern molding material

[29] 100 : foam

[30] 160, 180 : foam pattern

[31]

Best Mode for Carrying Out the Invention

[32] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Here, the detailed description of obvious facts in the related art will be omitted.

[33] The method of manufacturing foam according to the present invention basically includes the steps of preparing molding materials, joining the molding materials, placing the molding materials into a mold, and crosslinking and foaming the molding materials at the same time.

[34] Specifically, the step of preparing the molding materials is a step of individually preparing a body molding material, which is to be formed into a body of a final foam product, a cover molding material, which is to be formed into a cover for covering the body of the final foam product, and a pattern molding material, which is to be joined to one surface of the cover molding material thus exhibiting pattern on the surface of the final foam product, under the condition of suppressing crosslinking and foaming thereof, respectively. Methods of preparing each of the molding materials is not limited to any specific preparation method, as long as each of the molding materials can be realized under the condition of suppressing crosslinking and foaming thereof, and each of the molding materials may be prepared using any one of molding methods commonly known in the related field, such as injection molding, press molding, vacuum molding, combined molding method and the like.

[35] Further, the molding materials may be made of materials that are the same as or different from each other. Of course, there is also a case where some of the molding materials are made of the same material and the other of the molding materials are made of different materials. Further, there are also a case where the molding materials have the same color or different colors, and a case where some of the molding materials have the same color, and the other of molding materials have different colors. In this case, it goes without saying that there is also a case where the pattern molding materials include plural types of material and have different colors from each other.

[36] Since the shape of the body molding material may be variously changed depending on the shape of the final foam product, the shape thereof is not limited to any specific shape as long as it is precisely measured such that it can be realized into the shape of the final foam product. However, since molding materials, which are present under the condition of suppressing crosslinking and foaming thereof, have a certain level of hardness, it is preferred that the body molding material have a shape which enables the body molding material to be easily placed in a cavity of a mold for crosslinking and foaming. The cover molding material is a cover for covering the whole area or a

specific area of an outer surface of the body molding material, constituting the body of the final foam product. The shape of the cover molding material is not limited, but it is preferred that the shape, if possible, be planar. Particularly, it is more preferred that the cover molding material be of a thin film shape having a flat surface and uniform surface roughness under the condition of suppressing crosslinking and foaming thereof. The pattern molding material constitutes a part which is joined to one surface of the cover molding material and is exposed from the surface of the final foam product. Since the shape of the pattern molding material can be arbitrarily selected from among various patterns or characters depending on the purpose, the shape thereof is not particularly limited, and the pattern molding material may be formed into a thin film shape as with the cover molding material.

[37] Meanwhile, the cover molding material and the pattern molding material may be separately prepared in a desired size or shape in respective manufacturing processes, and then used. Alternatively, molding materials having a predetermined size may be prepared in advance, the prepared cover molding material and pattern molding material may be suitably cut into sizes required respectively in the respective manufacturing processes, and then the cut molding materials may be used as the cover molding material and the pattern molding material.

[38] FIG. 1 shows an example of a process of joining pattern molding materials to a cover molding material, including preparing a thin film shaped cover molding material 14 and two stripe-shaped pattern molding materials 16 having a different color from that of the cover molding material 14 under the condition of suppressing crosslinking and foaming thereof, respectively, and then joining the pattern molding materials 16 to one surface of the cover molding material 14, FIG. 2 shows a configuration in which the pattern molding materials 16 are joined to an upper surface of the cover molding material 14 shown in FIG.l, and FIG. 3 shows the sectional configuration taken along the line A-A'in FIG. 2.

[39] Meanwhile, when the pattern molding materials are joined to the cover molding material, the process of joining the pattern molding materials to the cover molding material may be not easily performed because the cover molding material has a certain level of hardness hardness. In the present invention, a process of heating the cover molding material within a temperature range in which deformation of the shape of the cover molding material due to the melting does not occur, and then joining the pattern molding materials to the cover molding material may be included.

[40] After one or more pattern molding materials are joined to one surface of the cover molding material, both the molding materials are placed on the inner surface of a mold having a predetermined shape. In the present invention, when the molding materials are placed into the mold, a process of placing one or more cover molding materials,

joined with the pattern molding material, into the mold such that one surface of the cover molding materials, combined with the pattern molding material, comes into close contact with an inner surface of the mold, and then placing the body molding material in the remaining space other than a space occupied by the cover molding material in the mold, may be used. However, the present invention is not limited thereto. Further, in the present invention, a process of joining the other surface of one or more cover molding material, which is not joined with the pattern molding material, to an outer surface of the body molding material and then placing the resulting joined molding materials into a mold, or a process of placing the body molding material into a mold and then inserting and placing one or more cover molding materials, combined with the pattern molding material, in the space between the outer surface of the body molding material and the inner surface of the mold, may be used.

[41] Further, where the cover molding material including the pattern molding materials combined thereto, and the body molding material, are placed in a mold, the cover molding material may be combined to all of the upper, lateral and lower surfaces of the body molding material, or may be combined to any one of the upper, lateral and lower surfaces of the body molding material.

[42] FIG. 4 shows a process of placing molding materials into the inner surface 22 of a mold 20, and specifically shows a process of placing a rectangular body molding material 12 and a cover molding material 14 shown in FIGS. 2 and 3 in the cavity of the mold 20. Here, after the molding materials are suitably placed in the mold, the mold 20 is closed with a mold 40 and then heated, and thus the molding materials are simultaneously crosslinked and foamed, thereby realizing foam 100 including foam patterns 160 having different colors formed on the surface thereof, as shown in FIG. 6,. That is, foam, on which various patterns and colors are formed, can be manufactured through only one foaming process without performing an adhering process or a coating process. Meanwhile, in this embodiment, the cover molding material and the body molding material are made of the same material. In this case, the cover molding material is integrated with the body molding material through a crosslinking and foaming process in a mold, thereby constituting part of the foam body.

[43] FIG. 7 shows another embodiment of foam which can be realized by joining pattern molding materials having various patterns to a cover molding material, according to the present invention, and shows an oblique line shaped foam pattern 163 and an asteroid foam pattern 164, which are formed on one of the outer surfaces of a foam body 140, and a foam pattern 162 which is formed on a bottom surface and lower end of lateral surfaces among the outer surfaces of the foam body 140 and has material properties different from the foam body. FIG. 8 shows a further embodiment of a foam which can be realized according to the method of the present invention, and shows a

foam pattern 180 protruding from one of the outer surfaces of a foam body 140 to the outside. Here, since the cover molding material is made of the same material as the body molding material, only the pattern and color of the pattern molding material is exhibited on the surface of the foam.

[44] Meanwhile, where the shape of a mold is variously changed, for example, by providing unevenness on the inner surface of the mold, protruding patterns, as shown in FIG. 8, may be obtained, or depressed patterns, which are not shown, may be obtained.

[45] Meanwhile, the present invention does not exclude a step of remolding or suitably cutting the foam obtained through the crosslinking and foaming step. Here, since the step of remolding or cutting foam is widely used in the related field, a specific description thereof will be omitted.

[46] In addition to the above embodiments, the present invention further provides a method of manufacturing foam, including the steps of preparing molding materials, combining the molding materials to each other, placing the molding materials into a mold, injecting foaming materials into the mold, and crosslinking and foaming the foaming materials and the molding materials. Hereinafter, this method of manufacturing foam of the present invention will be described in detail. However, in the description of this embodiment, elements that are the same as in the above mentioned embodiments will not be described.

[47] First, a cover molding material and pattern molding materials are suitably prepared under the condition of suppressing crosslinking and foaming thereof, the pattern molding materials are joined to one surface of the cover molding material, and then the cover molding material 14, combined with the pattern molding materials, is placed on the inner surface 62 of a mold 60 having a predetermined shape, as shown in FIG. 5. FIG. 5 shows a process of manufacturing foam using the pattern molding materials and cover molding material shown in FIG. 1 and 2.

[48] After one surface of the cover molding material 14 joined with the pattern molding materials 16 is placed in close contact with the inner surface 62 of the mold 60, the mold 60 is closed with a mold 80, and then foaming material is injected into the mold 60 through an injection hole 82 formed in the mold. The foaming material injected through the injection hole 82 is charged into the remaining space other than a space occupied by the one or more cover molding materials joined with pattern molding materials in the mold. After the foaming material are completely charged therein, the injected foaming material and the molding materials are simultaneously crosslinked and foamed by heating the mold, thereby obtaining the foam shown in FIG. 6, as in the above mentioned embodiments. The foaming materials are not particularly limited, as long as they can be crosslinked and foamed.

[49] As described above, although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.