JP2004195897A - Injection foamed molded product and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection foamed molded product having good dimensional precision in its terminal part and capable of being manufactured at a low cost, and its manufacturing method. <P>SOLUTION: This injection foamed molded product is manufactured by injecting a foamable resin raw material in a mold and subsequently opening the mold slighly. A resin non-foamed part 12 having the length corresponding to the slightly opened part of the mold is formed to the terminal part of the product and a resin foamed part is bent/expanded toward the resin non-foamed part 12 from the boundary part P of the resin non-foamed part 12 to form a horizontal terminal part. Further, an injected product having the resin non-foamed part 12 protruded to the terminal part by the slightly opened length by the recessed part 3 for forming the resin non-foamed part 12 provided to the upper end part of a male mold 2 and the resin foamed part is subsequently bent/expanded toward the resin non-foamed part 12 from the boundary part P of the resin non-foamed part 12 at the time of slight opening of the mold so that the terminal part forms a horizontal surface. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to an injection-foam molded article having good dimensional accuracy in a terminal portion and capable of being manufactured at low cost, and a method for manufacturing the same.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. 8-294925
2. Description of the Related Art Conventionally, injection foam molded articles have been excellent in light weight and cost performance, and are widely used as interior parts for automobiles such as door trims, as shown in Patent Document 1, for example. As a method of manufacturing such an injection foamed molded product, a foamed resin material is injected into a mold in a state in which a mold including a pair of detachable cavity molds and a core mold is closed, and then one of the molds is slightly removed. Generally, a method is used in which the foamed resin material is foamed along the inner surface of the mold by opening the mold.
[0004]
However, as shown in FIG. 4, when the mold is slightly opened after injecting the foamed resin material, the end a of the female mold (cavity mold) 21 and the end b of the male mold (core mold) 22 move. There was a phenomenon in which a gap was formed only for the mold opening (α). As a result, when assembled as an interior material, there has been a problem that a gap is formed between the components and other components or the components interfere with each other, and the appearance is significantly reduced.
In order to solve this, as shown in FIG. 5, a core mold 23 which can move up and down is provided in the male mold 22 and the core mold 23 is raised in synchronization with the opening of the mold. It has been studied to prevent the end portions a and b from coming apart. However, in this case, there is a problem that the production cost of the mold is extremely high and the number of days for producing the mold is long, so that the mold is not practically used.
[0005]
[Problems to be solved by the invention]
The present invention solves the above-described conventional problems, and has excellent dimensional accuracy and excellent appearance quality in the terminal portion, and can be manufactured at low cost and in a short period of time, thereby greatly reducing the production cost. It has been completed for the purpose of providing an injection-foam molded article and a method for producing the same.
[0006]
[Means for Solving the Problems]
The injection foam molded article of the present invention made to solve the above-mentioned problem is that, after injecting the foamed resin material into a mold having a pair of male and female molds which can be freely separated and opened, one of the molds is slightly opened. An injection-foamed molded product manufactured by foaming a foamed resin material along the inner surface of a mold, wherein a resin unfoamed portion corresponding to a slightly open length is formed at a terminal portion, and a boundary portion of the resin unfoamed portion. The resin foamed portion bends and bulges toward the resin non-foamed portion from the starting point to form a horizontal terminal portion.
In addition, the method for producing an injection-foam molded article of the present invention comprises, after injecting a foamed resin raw material into a mold having a pair of male and female molds which can be freely separated and separated, slightly opening one of the molds to reduce the foamed resin raw material. In the method for producing an injection-foam molded article in which a foam is formed along an inner surface of a mold, a resin unfoamed portion protruding by an opening length at a terminal portion by a concave portion for forming a resin unfoamed portion provided at an upper end of the male mold. The exhibit is formed, and then the resin foamed portion is bent and expanded toward the resin non-foamed portion side from the boundary portion of the resin non-foamed portion at the time of opening, and the terminal portion forms a horizontal plane. is there.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
The drawings show a case where the present invention is applied to molding of a door trim for an automobile. FIG. 1 is a cross-sectional view showing a main part of an injection foam molded product obtained by the present invention, and FIG. 2 shows a main part of a molding die. FIG. 3 is a sectional view showing the molding step.
In the figure, 1 is a female mold (cavity mold), 2 is a male mold (core mold), and after injecting the foamed resin material into a molding die composed of a pair of male and female molds, one of the molds (illustrated in FIG. In this method, the female mold 1) is slightly opened, the foamed resin material is applied to the inner surface of the mold and foamed to produce an injection foamed molded product, which is the same as the conventional one.
[0008]
In the present invention, a concave portion 3 for forming a resin non-foamed portion is provided at an upper end portion of the male mold 2, and the resin non-foamed portion 12 protruding from the edge portion by a slight opening length is provided by the concave portion 3. An injection product 10a having the same shape is formed. Then, when the resin foam portion is bent and expanded toward the resin non-foam portion from the boundary portion P of the resin non-foam portion 12 at the time of slightly opening, the terminal portion forms a horizontal plane. It is characterized by the following points.
In other words, the present inventor has formed a resin unfoamed portion 12 at the edge portion by protruding, and when the mold is slightly opened, the resin foamed portion 12 starts from the boundary portion P of the resin unfoamed portion 12 as a starting point. The present inventors have found that the foam is formed while being bent and swollen toward the part side, and the present invention has been accomplished.
That is, as shown in FIG. 3, if a resin non-foamed portion 12 having a height (α) and a predetermined width (s) of the mold is formed at the edge portion by the concave portion 3, The foamed portion 12 follows the opened mold when the mold is opened and maintains the shape as it is, and the resin foamed portion bends toward the resin non-foamed portion from the boundary portion P and foams. The edge portion is drawn from the boundary portion P as a starting point without swelling downward by α as in the related art, thereby forming a horizontal terminal portion.
[0009]
According to the findings of the present inventor, when the contact distance with the mold is 1.5 mm or less, the resin is cooled and solidified by the mold to form a resin unfoamed portion. In the present invention, the opening dimension (α) of the mold is as small as about 1 mm, so that the shape of the concave portion 3 has the same height as the opening dimension (α), and the width (s) is 1.5 mm or less. What is necessary is just to design so that it may become.
[0010]
Next, the manufacturing process of the present invention will be described. After injecting the foamed resin raw material into a mold composed of a pair of male and female molds 1 and 2 which can be separated and separated, one of the molds is slightly opened slightly to expand the foamed resin. It is the same as the conventional method in the production method of the injection foam molded article in which the raw material is attached to the inner surface of the mold and foamed.
In the present invention, as shown in the left diagram of FIG. 3, the resin mold projecting from the edge by the slightly opened length by the resin non-foamed portion forming recess 3 provided at the upper end of the male mold 2. An injection product 10a having a foam part 12 is molded. Next, the resin is foamed by slightly raising the female mold 1, and the resin foamed part is bent and expanded toward the resin non-foamed part from the boundary P of the resin non-foamed part 12 at the time of this slight opening. The terminal section forms a horizontal plane (see the right diagram in FIG. 3).
[0011]
As shown in FIG. 1, the entire surface of the injection foam molded article manufactured as described above is covered with a skin layer 11, and a resin unfoamed portion 12 is formed at the terminal portion for a slight open length. In addition, the resin foam portion bends and bulges toward the resin non-foam portion side from the boundary portion P of the resin non-foam portion 12 as a starting point to form a horizontal terminal portion. There is no gap in the terminal part due to the mold opening (α). Therefore, when assembled as an interior material, it is possible to eliminate all the problems that a gap is formed between other parts or interference and the appearance is remarkably reduced, and it is possible to move up and down in the mold. It is possible to manufacture the mold at low cost and in a short period of time without having to separately provide a core mold.
[0012]
【The invention's effect】
As is clear from the above description, the present invention has excellent appearance quality with good dimensional accuracy in the terminal portion, and can produce the mold at low cost and in a short period of time, thereby greatly reducing the production cost. Things.
Therefore, the present invention greatly contributes to industrial development as an injection-foam molded article and a method for producing the same, which have eliminated the conventional problems.
[Brief description of the drawings]
FIG. 1 is a sectional view of a main part showing an embodiment of the present invention.
FIG. 2 is a sectional view of a main part of a molding die.
FIG. 3 is an explanatory view showing a molding step of the present invention.
FIG. 4 is a sectional view showing a conventional example.
FIG. 5 is a sectional view showing another conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Female type 2 Male type 3 Concave part 12 Resin unfoamed part P Boundary part

Claims (2)

After injecting the foamed resin material into a mold consisting of a pair of male and female molds that can be freely separated and opened, one of the molds is slightly opened, and the foamed resin material is attached to the inner surface of the mold and foamed. In addition, a resin unfoamed portion corresponding to the slightly open length is formed in the terminal portion, and the resin foamed portion bends and bulges toward the resin unfoamed portion side from the boundary portion of the resin unfoamed portion as a starting point, and the horizontal portion is formed. Injection-foam molded article characterized by forming a flexible terminal portion. After injecting a foamed resin material into a molding die composed of a pair of male and female molds that can be separated from each other, one of the molds is slightly opened, and the foamed resin material is attached to the inner surface of the mold and foamed. In the above, an injection product having a resin non-foamed portion protruding by an opening length at an edge portion by a concave portion for forming a resin non-foamed portion provided at the upper end portion of the male mold is formed, A method for producing an injection-foamed molded product, wherein a resin foamed portion is bent and bulged from a boundary portion of a foamed portion toward a resin non-foamed portion, and a terminal portion forms a horizontal plane.

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