KR100676275B1 - Injection molding process - Google Patents

Abstract

An injection molding method is provided to reduce defects of a foam by performing a crosslinking process at the state where a functional foam unit is stable so that an invasion is prevented between a foam material and the functional foam unit. An injection molding method comprises a step of processing a pre-form at the state where a crosslinked foaming is suppressed; a step of preparing a mold including a cavity having a predetermined shape and a plurality of pins protruded from the cavity; a step of loading the pre-form on the pins of the mold; and a step of closing the mold, and foam molding a foam material and the pre-form loaded on the pins at the same time by injecting a foam material into the cavity of the mold.

Description

Injection molding process

1 is a schematic flow chart showing a preferred method of injection molding in accordance with the present invention.

2A to 2D are each a perspective view showing various configurations as an embodiment of the linear molded body according to the present invention.

Figure 3 is a schematic diagram showing the step of placing the linear molded body in the injection mold as an embodiment according to the present invention.

4A to 4C are cross-sectional views showing schematic correlations between the pins of the injection mold and the linear molded body placed as other embodiments according to the present invention.

Figure 5 is a schematic configuration showing the step of placing the linear molded body in the injection mold as another embodiment according to the present invention.

6A to 6D are cross-sectional views of various various composite foams obtained when the linear molded body disclosed in each of FIGS. 2A to 2D is produced using the injection mold disclosed in FIG. 4A.

Explanation of symbols on the main parts of the drawings

10, 11: linear molded body 100: composite foam

110: functional foam portion 220: upper mold

260: lower mold 262: mold cavity

263: groove 264: settlement means

265: support plate

Republic of Korea Patent Publication No. 2004-065070

The present invention relates to an injection molding method, and more particularly, to an injection molding method of a foam capable of being made of different physical properties at a desired position in the final foamed product.

Injection molding means that a foamed material made of a thermoplastic resin or the like is heated to a molten state, and a molten foamed material is injected into a cavity of a mold maintained at a constant temperature at high speed and high pressure to cool, and then the mold is rapidly cooled. It is a method of opening and obtaining a foam as a final product form, which includes the root shoe parts due to the advantage that the processing process can be simplified compared to the press molding method, thereby improving work efficiency and reducing time and economic loss. Is widely used in the production of foam products.

However, the injection molding method is different from the pressure molding method in which the mold is sealed by appropriately placing a solid foam material having a certain shape such as a sheet or pellet in the cavity and then sealing the mold to undergo a crosslinking process. The foamed product that can be finally realized by injection molding method is required because of the characteristic of forcedly injecting the foamed material in the molten state without the constant shape into the cavity through the foaming material injection path provided on one side of the mold. There is a limitation that can be made of a single physical property or of a single color.

In recent years, the demanding customers prefer foamed products having various functionalities or different colors by different properties for each part, rather than single or physically colored foam products, and this trend is increasing day by day. In order to maximize the productivity of the injection molding method and to realize the final foamed product having different physical properties or different colors for each part, the part that becomes the main body of the final foamed product is manufactured by injection molding, and Parts of each part having different properties (or different colors) are manufactured in a separate process by injection molding or press molding, and then placed through a series of processes in which each manufactured component is bonded to an appropriate position on the main body. Depending on the physical properties or And it manufactures foam products having different phases.

However, this composite method was introduced to take full advantage of the injection molding method of reducing the manufacturing cost due to high productivity, but in reality, a separate foaming process is required as well as a separate foaming process for producing parts for each part. Since it must be accompanied by the manufacturing equipment and labor accordingly had a disadvantage. In addition, the bonding process is performed by hand, and in the case of the injection process, the parts of each part may not be accurately adhered to the intended position, or in case of excessive use of the adhesive, the defect rate of the product may be increased and productivity may be lowered. The reality is that it does not live up to its original intention.

Korean Patent Laid-Open Publication No. 2004-065070 is proposed to implement a foam having different properties or colors for each part without a separate bonding process by improving the disadvantage of the injection molding method, the process using a low-temperature mold Formed cold inserts with different colors or properties in the form of cross-linked foam suppressed, the prepared cold inserts are placed in a desired position inside the injection mold, the mold is sealed, and the molten foam material is placed inside the mold. It is a technical feature of crosslinking and foaming a cold insert part and foaming material simultaneously by injecting into a crosslinking process for a predetermined time.

 At first glance, this technique allows a cold insert part of different physical properties or different colors to be crosslinked simultaneously with a foam material and a single mold. It is expected to reduce the manufacturing cost to some extent by taking full advantage of the injection molding method compared to the technology.

However, this technique adopts the method of placing the cold insert part at any position in the cavity of the mold without any fixing device, then sealing the mold and injecting the foam material. In consideration of the method of filling the cavity of the mold by injecting at a high speed, there is a problem that it is practically impossible to undergo a crosslinking process together with the foam material in a state where the cold insert is fixed at the original position by the foam material injected at high speed and high pressure. . Therefore, when performing injection molding by this technique, it is obvious that the cold insert part may be formed at a point other than the intended point, and thus securing the functionality of each part, which is the original purpose, will be difficult to achieve completely.

The present invention has been made to solve the above problems, an object of the present invention is to provide a method for producing a composite foam having different physical properties or different colors for each part by injection molding method.

It is another object of the present invention to provide an injection molding method in which a functional material placed at an arbitrary position according to the intention of an operator may undergo a crosslinking process at its original position without being affected by the foamed material injected at high speed and high pressure into the injection mold. In providing.

Another object of the present invention is to provide a molding method that can make the most of the productivity advantages of the injection molding method by allowing the foam to change the function of each part in one process without adding a separate bonding process. Is in.

The present invention relates to a method for producing a foam by injection molding a material in order to achieve the above object, the step of processing a linear molded body of any shape in the state in which cross-linked foam is suppressed, and the cavity formed of an arbitrary shape Preparing a mold comprising a plurality of pins as a settling means protruding at an arbitrary position of the cavity and the cavity; placing the linear molded body on the pins of the mold; And a step of simultaneously molding the foamed material and the linear molded body placed in the seating means by injection into the mold cavity.

Temporarily cooling the mold in the heated state is further added before the foam molding is completed and before the new linear molded body is placed in the pin of the mold.

Prior to placing the linear molded body on the pins of the mold, or before placing the linear molded body on the pins of the mold and closing the mold, the step of placing one or more linear molded objects of any shape in close contact with any part of the mold cavity may be carried out. It is characterized by being further added.

The linear molded body is characterized by consisting of a complex structure of different materials or colors.

In addition, all of the linear molded body, or any one or more selected from the linear molded body is characterized in that the thin film.

The pin of the mold is characterized in that it is provided in any one of the mold cavity portion selected from the upper mold and the lower mold constituting the mold, or both the cavity of the upper mold and the lower mold.

In addition, the pin of the mold is characterized in that the removable with respect to the cavity of the mold.

The pin is characterized in that provided on the support plate detachable to the groove portion formed in one or more of the cavity portion of the mold.

The foamed material injected into the linear molded body and the mold cavity is characterized in that it is made of any one selected from the same or different materials.

The linear molded body is formed of a different color from the foam material injected into the mold cavity.

The preferred technical configuration of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, detailed descriptions of technologies that are not related to the preferred technical configuration of the present invention or widely known in the related art will be omitted. do.

As disclosed in FIG. 1, the present invention basically includes processing a linear molded body having an arbitrary shape using a material, and placing the prepared linear molded body at an arbitrary position inside an injection mold having a cavity having an arbitrary shape. And sealing the injection mold and injecting the foaming material to crosslink the foamed product and the foaming material simultaneously.

The linear molding processing step is to prepare a molding material having an arbitrary shape in a state in which crosslinked foaming is suppressed.

The linear molded material according to the present invention as a molding material is not limited to any specific material as long as the material can be embodied as a foam by a molding method, which is the same as the foam material injected into an injection mold. Is the same kind of material or the content ratio is different) or any one selected from different materials, or includes a plurality of combinations of different materials from each other, of course. However, in consideration of the fact that the linear molded body constitutes the functional foam part in the composite foam according to the present invention, it is preferable to select in consideration of the functions to be performed in the composite foam as the final product. On the other hand, the linear molded body may further include any one or more selected from a variety of different types of pigments to produce a variety of color effects in appearance, and of course, the present invention further comprises a case where the linear molded body is made of a composite structure consisting of a variety of materials Does not exclude cases in which pigments of different colors are included.

The shape of the prepared linear molded body is preferably formed into a thin film having a predetermined surface roughness (surface roughness of a predetermined level or less), but the present invention is not limited thereto, and the linear molded body is widely used as a molding material in the related art. It does not exclude the case which consists of a sheet form, a pellet form, etc., and does not exclude the case where the linear molded object is formed in the composite structure of the individual linear molded objects which respectively have various shapes. Therefore, the shape of the linear molded body is performed in a composite foam as a final product, as well as in manufacturing aspects such as the ease of forming the interface to be described later, the easy configuration of the composite structure, the easy placement into the mold pin, rather than uniformly determined It is desirable to make a decision considering the functional aspects that should be taken.

In each of FIGS. 2A to 2D, various cases are disclosed in which the overall shape is a circular shape of a flat plate as an example of the linear molded body according to the present invention. Specifically, FIG. 2A discloses a single flat plate linear molded body 11, and FIG. 2B discloses a laminated structure 12 and 13 of flat plate linear molded parts formed of different materials (or different colors). 2c discloses a two-part structure 14, 15 of a flat circular linear molded body made of different materials (or different colors), and in FIG. 2d the same material (or the same color) in opposing pairs. Disclosed are four divided structures 16 and 17 of a flat plate linear molded object.

When the linear molded body is processed and prepared, the linear molded body is placed in a cavity of an injection mold having an arbitrary shape. The linear molded body 10 similar to the linear molded object having a flat plate shape shown in FIG. 2A is placed in the cavity of the injection mold. An example of placing is shown in FIG.

Injection mold (220, 260) according to the present invention includes a cavity portion 262 made of a shape corresponding to the shape of a variety of foam products made of a specific shape, and a plurality of settle means protruding from any position of the cavity portion It is preferable to make. The placing means is technical in that the linear molded body functions to be foamed without leaving the intended position in the cavity of the injection mold. The shape and structure of the seating means, whether the linear molded body is fixed in the seated position can be stably foamed, and how the shape of the seating means in the cavity volume of the mold affects the appearance of the final foamed product It will be desirable to determine whether or not to comprehensively consider. In FIG. 3, the case where the settlement means 264 which consists of a pin shape as an example of settlement means is provided in the cavity part of a metal mold | die is disclosed.

On the other hand, each of Figures 4a to 4c discloses some examples of injection molds that can be configured in different positions when the pin is adopted as an example of the settling means according to the present invention. In detail, FIG. 4A illustrates that the linear molding 10 includes a settled means 264 in the cavity 262 of the lower mold 260 so that one side surface of the linear molded body 10 is exposed to the outside. 4b shows a case in which the placing means 224 and 264 are provided in the upper and lower molds 220 and 260 so that the linear molded body can be formed in the center of the composite foam. One linear molded body is provided with upper and lower molds 220 and 260 in the upper and lower molds 220 and 260, respectively, so that the linear molded parts can be formed at one upper end of the composite foam and the other linear molded part is formed at the other lower end of the composite foam. Show the case.

As described above, since the linear molding constitutes a functional foam in the composite foam implemented according to the present invention, the position of the linear molded body in the composite foam is determined uniformly according to the contents of the work performed in consideration of various various functions. It can be changed in various ways. Therefore, at what position in the cavity of the injection mold is to be provided, whether the settlement means are to be provided at both the upper mold and the lower mold of the injection mold or at any one selected, In the case where both the upper mold and the lower mold of the mold are provided, whether or not to settle the mutually facing means, and if so, whether or not the gap is to be changed is a matter that can be freely changed. I never do that.

In addition, the present invention is described in any one of the steps selected before the step of placing the linear molded body of any shape in the settlement means of the mold, or the step of placing the linear molded body in the settlement means of the mold and before closing the mold. Similar to the example of Korean Patent Laid-Open Publication No. 2004-065070, the step of placing one or more linear molded parts formed in any shape in close contact with any part of the mold cavity is further excluded. The position of the linear molded body placed in this step is not particularly limited, but it is preferable to determine in consideration of the possibility that the linear molded object may be changed at the initial position by the high pressure foam material injected into the mold. Of course, the above-described description of the linear molded body may be applied to the linear molded object added at this step.

On the other hand, it is preferable that the fixing means of the mold is fixedly provided to the cavity of the injection mold in consideration of the function that the linear molded body can be foamed at the intended position without being flowed by the foam material injected at high speed and high pressure. Since the injection mold is continuously received from the external heat source during the working process and maintained above a certain temperature, the portion of the linear molded body placed in the seating means directly contacting the seating means is melted by high temperature heat and There is a possibility that the implementation of the intended functional foam part becomes difficult.

In order to accomplish this, the material of the placing means itself is selected from a material having a high hardness as well as having a very low thermal conductivity and integrally included in the injection mold, or made of the same or similar material as the mold. By forming grooves in the cavity of the mold so that the settled means can be used interchangeably, the settlement means are detachably formed with respect to each of the grooves so as to block heat transfer from the injection mold to the linear molded body in advance before the foam molding, or We propose a method of combining both of them.

In the first case, only the step of placing the linear molded body on the settled means provided in the mold cavity can be added, so that the productivity of the composite foam can be expected. In the second case, the removal means, which are kept at a high temperature in each injection process, must be removed, and then the insertion means, which are kept at room temperature (or a temperature that can prevent melting of the linear molded body), must be inserted and fixed in the cavity of the mold. Although the work is added, it is possible to block the heat transferred from the injection mold to the preform before the foam molding step, so that the effect can be realized in the exact shape in the intended position in the functional foam foam molding. On the other hand, the third combination, which takes advantage of these two methods, may be ideal, but it is easier to make molds than to determine them uniformly; It would be desirable to consider whether or not a combination.

In addition, in the present invention, when the placing means is detachably formed with respect to the cavity of the mold, as shown in FIG. 5, the groove 263 having an arbitrary shape is formed in the cavity 262 of the mold, and the placing means ( 264 does not exclude the case provided in the support plate 265 detachable from the groove 263. In this embodiment, it is expected that the linear molded body settling process can be made easier than in the case where each of the above-described settling means is detachable to the mold cavity.

It is preferable that the grooves 263 and the support plate 265 have the same shape, and the grooves 263 may be formed in plural numbers at arbitrary positions of the mold cavity 262. Of course, it can be formed in any one of the mold cavity or selected from the mold. In addition, even in this embodiment, the case where the placing means 264 is detachable with respect to the support plate 265 is not excluded, and the material of the placing means and the support plate is not particularly limited, but the material having high hardness as well as very low thermal conductivity. It is preferable that it consists of any one selected from among.

In addition, although the state in which the linear molded body is placed on the upper end of the mounting means is disclosed in the drawings, the present invention does not exclude the case in which the linear molded body is settled in the state penetrated by the mounting means. Of course, the case where the guide portion, such as a damper, is further provided in the cavity of the injection mold in order to prevent the linear molded body placed in the seating means by the foaming material from being released from the intended position.

Reference numeral 266, which is not described, refers to an injection path into which the foam material is injected.

On the other hand, in the conventional injection molding method, when the mold is heated to a high temperature of about 160 ° C to 180 ° C by an external heat source, when the foam material is injected into the cavity inside the closed mold and foamed, the mold is opened to open the final foamed product. After demolding, the mold is sealed again to repeat the above process. However, in the case where the linear molded body is placed in the settlement means of the mold maintained at a high temperature, a part of the linearly shaped body which is in contact with the settling means may be melted. Such melting is performed by the linear molded body originally intended in the cavity of the mold. There is a fear that implementation of the composite foam according to the present invention will be difficult as it leaves the position.

Therefore, the present invention further proposes a method in which a linear molded body is placed in the mold placing means after the mold is temporarily cooled to a temperature below a predetermined temperature after the foam molding step. Cooling of the mold can be assumed a method such as a water jacket which is widely used as a mold cooling means, but the present invention is not limited to this method as long as the mold can be cooled properly. In addition, the cooling temperature of the mold should be determined in consideration of efficient heat transfer to the mold, production efficiency, and the like, but is preferably made within the range of 40 ° C to 80 ° C.

When the linear molded body is properly placed in the settled means of the injection mold, the injection mold is sealed, and then the foam material is injected into the cavity of the injection mold made of any shape in which the linear molded object is placed through the injection path to provide a space for the linear molded object to occupy. Fill the cavity of the injection mold. Since the injection mold receives heat continuously from an external heat source, the linear molded body is placed in the seating means, and the foam material filling the part other than the space occupied by the linear molded object is simultaneously crosslinked in the filled position. After passing through a predetermined time, and then rapidly opening the injection mold is obtained a composite foam according to the present invention.

That is, the composite foam including a conventional foam and a functional foam having a certain function, such as a special physical property or color at any position of the foam, rather than a method of bonding and recombining it after a separate injection molding method It can be implemented by a single injection molding method.

6A to 6D each prepare a linear molded body disclosed in each of FIGS. 2A to 2D, and then inject a foam material made of a different material from each linear molded object by using an injection mold having a settling means as illustrated in FIG. 4A. An example of a composite foam foamed through a crosslinking process is shown.

According to a simple method as shown, each of the composite foam 100 according to the present invention, a functional foam 110 consisting of different physical properties (or colors) at a specific site is formed (FIG. 6a), or a layer at a specific site Alternatively, functional foams 120 and 130 formed of different physical properties (or colors) are formed (FIG. 6B), or a specific portion exposed to the outside is formed of various functional foams 140 or different physical properties (or colors). 150, 160, 170 are shown (FIG. 6C, 6D).

In the above, the present invention is limited to the preferred embodiments of the present invention. However, the present invention is not limited thereto, and various changes or modifications can be made without departing from the spirit thereof.

The present invention provides a foamed product manufactured by an injection molding method, wherein the functional foam formed at an arbitrary position is properly controlled so as to undergo a crosslinking process in a stable state without departing from the intended position, thereby forming a boundary between the foam material and the functional foam part boundary. There is an advantage that can significantly reduce the defective rate of the final foamed product by preventing the invasion phenomenon.

In addition, the present invention is to produce a foamed product having different physical properties or different colors in the desired position by different materials for each part by a single injection molding method without a separate foaming process and bonding process By making it possible to realize the productivity benefits of the injection molding method.

Claims (10)

A method of producing a foam by injection molding a material, Processing the linear molded body having an arbitrary shape in a state where crosslinked foaming is suppressed; Preparing a mold comprising a cavity having an arbitrary shape and a plurality of pins as settling means projecting from an arbitrary position of the cavity; Placing the linear molded body on a pin of the mold; Sealing the mold and injecting a foam material into the mold cavity to simultaneously foam-forming the foam material and the linear molded body placed in the settlement means; Injection molding method, characterized in that it can be produced by a single injection molding a composite foam having a different color or physical properties for each part. The method of claim 1, And temporarily cooling the mold in a heated state before the foam molding is completed and the new wire molded body is placed in the pin of the mold. The method of claim 1, Prior to placing the linear molded body on the pin of the mold, or before placing the linear molded body on the pin of the mold and closing the mold, the step of placing one or more linear molded objects of any shape in close contact with any part of the mold cavity may be carried out. Injection molding method, characterized in that further added. The method of claim 1, The preform is an injection molding method, characterized in that the composite structure of different materials or colors. The method of claim 4, wherein Injection molding method, characterized in that all of the linear molded body, or any one or more selected from the linear molded body is formed in a thin film shape. The method of claim 1, The pin of the mold is injection molding method characterized in that it is provided in any one of the mold cavity portion selected from the upper mold and the lower mold constituting the mold, or both the cavity of the upper mold and the lower mold. The method of claim 1, And the pin of the mold is detachably provided with respect to the cavity of the mold. The method of claim 7, wherein The pin is injection molding method, characterized in that provided in the support plate detachable to the groove portion formed in at least one cavity portion of the mold. The method of claim 1, The foaming material injected into the linear molded body and the mold cavity is injection molding method, characterized in that made of any one selected from the same or different materials. The method of claim 1, And the linear molded body is formed of a different color from the foamed material injected into the mold cavity.

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