JP2006341486A - In-mold molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-mold molding machine which is excellent in transfer properties to the angular part of a resin molding and effective to prevent a defective appearance by the adhesion of dust to the inside of a mold and an in-mold molding method. <P>SOLUTION: The in-mold molding machine 10 for the decorative resin molding 1 comprises an injection molding mold comprising a cavity mold 20 and a core mold 30 and a gas supply means ejecting gas toward a decorative film 40 inserted between the cavity mold 20 and the core mold 30. A gas ejection opening 33 is the angular part 1a of a resin body to be injection-molded and arranged to eject the gas toward a decorative film 40 part corresponding to a decorative part. The gas supply means gasifies fluid generated by using a super critical fluid generator etc., and can be adjusted at a prescribed temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-mold molding apparatus that decorates the surface of a resin body simultaneously with injection molding of the resin body and a method for manufacturing an in-mold molded product.

In-mold molding is a technique in which a decorative film is brought into close contact with a cavity, and a pattern portion on the decorative film is transferred to a resin molded product simultaneously with molding.
However, if the concave and convex shape of the shape part to be decorated of the resin molded product is complicated and the corner of the corresponding cavity is acute, even if the decorative film is brought into close contact with the cavity surface by vacuuming etc. There is a problem in that the decorative film does not stretch that much, or the transfer ink does not stretch, resulting in unevenness and sharpness in the decorative pattern.
In order to improve the transferability of the corners, decorative films and inks that are easy to stretch have been actively developed, but there is also a problem that molding defects frequently occur due to severe restrictions on molding conditions. there were.
Moreover, dust and dust adhering to the decorative film are brought into the mold as they are, which is one of the causes of molding defects.
Japanese Patent No. 3150759 discloses a technique in which a pressurized gas is applied to a molten resin to prevent wrinkles due to sink marks or the like in the thick corners of the resin molded product, but the decorative film has little elongation. However, the problem remained in that transfer unevenness occurred at the corners.
In addition, there is a method of heating the printing surface film part to be molded with a heater before inserting the mold into the mold, but since the film stretches, there is a problem such as inaccuracy and loss of movement time in the mold. There was a problem of cooling, and there was a limit to deep drawing.

Japanese Patent No. 3150759

  In view of the above technical problem, the present invention is an in-mold molding apparatus and an in-mold molding method that are excellent in transferability to corners of resin molded products and effective in preventing appearance defects due to dust adhering to the mold. The purpose is to provide

A first technical gist of the present invention is an in-mold molding apparatus for a decorative resin molded product, which is an injection molding die composed of a cavity die and a core die, and an additive inserted between the cavity die and the core die. A gas supply means that blows out toward the decorative film, and the gas outlet is disposed at a corner of the resin body to be injection-molded and discharged toward the decorative film portion corresponding to the decorative portion. It is characterized by being made.
Here, it is preferable that the gas supply means gasifies the fluid generated using a supercritical fluid generator or the like and adjusts it to a predetermined temperature.

The blowing direction (discharge direction) of the gas outlet is directed to the corner of the cavity surface when the decorative film is sandwiched between molds and clamped, so that the gas blown from the gas outlet can be The purpose is to intensively apply to the corner equivalent portion of the decorative film transferred to the corner portion.
In other words, since this corner-corresponding portion is positioned between the vicinity of the cavity surface corner and the core mold, the gas body is blown toward the corner-corresponding portion between them by blowing toward the cavity surface corner It is.
In this manner, the corner-corresponding portion is locally softened by blowing the gas intensively.
For example, if the cavity mold is provided with a suction hole leading to the cavity, and the vacuum suction is performed before the molten resin is injected, the degree of adhesion between the decorative film and the cavity surface is improved as compared with the conventional one. It adheres smoothly.
Further, in some cases, a product having a large cutout shape other than the corner may require a large elongation in the decorative film and the ink, and it is also an object of the present invention to provide a gas outlet at the site. One.
As the gas to be sprayed, a gasified supercritical fluid is used, which has a high permeability to the decorative film and quickly softens and modifies the film. A so-called hydrophilic effect is obtained.
Examples of such gas include carbon dioxide and nitrogen.
Further, when the gas temperature is heated to about 80 to 200 ° C., it penetrates faster and is effective.

Before inserting the decorative film between the cavity mold and the core mold, if there is a gas blowing means for blowing gas on both sides of this decorative film, dust etc. adhering to the decorative film is put in the mold Prevent it from being brought in.
Moreover, when a gas temperature shall be 30 degreeC or more, a decorating film will be heated preliminarily.

  An in-mold molding method using such an apparatus includes a step of inserting a decorative film between the molds of an injection mold composed of a cavity mold and a core mold, and a position for decorating a corner of a resin body to be injection molded. It has the process of spraying a permeable gas on the decorating film corresponding to, and the process of injecting molten resin.

  In the in-mold molding apparatus according to the present invention, after the decorative film for transferring the pattern to the corner of the resin molded product is accurately positioned and fixed in the mold, it is inert and permeable from the gas outlet provided in the core. Blow high gas immediately before in-mold molding to soften / modify the corner equivalent part, and in-mold molding can be performed with as close contact as possible to the corner of the cavity, so inject high temperature resin Thus, transfer defects at the corners of the resin molded product can be effectively prevented.

In addition, since dust and dust on the film surface can be removed by blowing gas toward the double-sided film surface of the decorative film before in-mold molding, it prevents appearance defects due to adhesion of dust and dust in the mold. To do.
In addition, by preliminarily heating the decorative film, the molding time can be shortened, and productivity can be improved.

A schematic view of the vicinity of an injection mold of the in-mold molding apparatus according to the present invention is shown in FIG.
FIG. 1 (a) shows a longitudinal sectional view, FIG. 1 (b) shows a plan view, and illustrations of injection devices and the like other than the main parts near the parting line of the molding die are omitted.
The in-mold molding apparatus 10 arranges a core mold (movable mold) 30 and a cavity mold (fixed mold) 20 constituting an injection mold, and drives the core mold 30 to open and close up and down.
Between the core mold 30 and the cavity mold 20, the decorative film 40 is passed sideways using a film supply device (not shown) so as to intermittently feed the pattern portion 40 c.
The decorative film 40 includes a pattern portion 40c that is transferred to a resin molded product on the base film 40b.
The cavity 35 formed between the core mold 30 and the cavity mold 20 is filled with molten resin in a clamped state, and the pattern portion 40c is transferred to mold a resin molded product.
The core mold 30 has a plurality of gas outlets 33 that are discharged toward the cavity 35 in the core 31, and communicates with the gas inlet 32 and the gas flow path 34.
This portion of the gas flow path 34 is drawn through to make it easier to understand.
An in-mold molding apparatus according to the present invention comprises a supply means by gasifying a fluid produced by a supercritical fluid generator or the like, and gasses an inert gas such as carbon dioxide or nitrogen that is highly soluble in a resin. It feeds into the cavity from the intake.
In this case, the gas temperature can be adjusted to 80 to 200 ° C. between the supercritical fluid generator and the mold.
Further, the gas blowing direction is adjusted to be the corner portion 1a of the resin molded product 1 to be injection-molded and the position of the decorative film corresponding to the transferred portion.
The cavity mold 20 is provided with a suction hole 21 leading to the cavity 35 for vacuum suction of the cavity 35.
Each of the core mold 30 and the cavity mold 20 is provided with a heater (not shown) so that the mold temperature can be adjusted.

The in-mold molding apparatus 10 is provided with blowing gas outlets 14a and 14b for blowing gas onto the surface of the decorative film 40a before passing between the molds 20 and 30.
The blow outlets 14a and 14b are arranged on both sides of the front surface 41 and the back surface 42 of the decorative film 40a, respectively, so that the gas 11 can be blown toward the delivery side of the decorative film 40. Yes.
Thereby, dust and dust on the surface of the decorative film can be blown off, or the decorative film 40 can be preliminarily heated.
Immediately before the in-mold forming step, the heating of the decorative film 40 is preliminarily heated in such a range that the film does not stretch, thereby shortening the heating time of the decorative film 40 in the cavity 35 and improving the production efficiency. I can do it.
Further, the decorative film 40 prevents dust and dust from adhering by passing through the pipe 15 up to the front of the injection mold.

The operation at the time of in-mold molding will be described with reference to FIG.
FIG. 2A shows a state where the decorative film 40 is positioned between the core mold 30 and the cavity mold 20.
Next, the decorative film 40 is clamped by the clamp 22 in a positioned state as shown in FIG.
Then, the core mold (movable mold) 30 is lowered and clamped as shown in FIG. 2C, and the decorative film 40 is pushed into the cavity 35 by the core 31.
In this state, the gas 11 at 80 to 200 ° C. is blown out from each outlet 33 toward each cavity face corner 35b.
Since the corner | angular part equivalent part 43 of the decorating film 40 is located between the blower outlet 33 and the cavity surface corner | angular part 35b at this time, the gas body 11 sprays on the corner | angular part equivalent part 43 of the decorating film 40 It is done.
Thereby, the corner equivalent portion 43 is intensively softened by the gas 11 having a high temperature of about 80 to 200 ° C., and the surface thereof is easily modified to be in close contact with the molten resin.
At this time, the decorative film 40 is brought into close contact with the cavity surface 35a as shown in FIG.
As shown in FIG. 2 (e), the molten resin 2 is injected and filled into the cavity 35 to decorate the resin molded product 1 as shown in FIG.
In the corner portion 1a of the resin molded product 1, the corner portion corresponding portion 43 of the decorative film 40 is filled with the resin in close contact with the cavity surface corner portion 35b, so that the pattern to be transferred is wrinkled, cracked, overlapped, Alternatively, transfer defects such as haze can be prevented.
Moreover, since the high temperature gas body 11 is sprayed by the blower outlets 14a and 14b and the temperature is raised beforehand, the decorative film 40 reduces the temperature difference between the molten resin 2 and the decorative film 40. And the hot water flow becomes better.
Thereby, the entrainment of gas or vapor into the resin molded product 1 is prevented, and the occurrence of a flow mark is prevented.

The schematic diagram of the principal part near the injection mold of the in-mold molding apparatus which concerns on this invention is shown. Explanatory drawing of operation | movement in the metal mold | die part of an in-mold shaping | molding apparatus is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin molded product 1a Corner | angular part 2 of resin molded product 2 Molten resin 10 In-mold molding apparatus 11 Gas body 12, 13 Hose 14a, 14b Gas body outlet 15 for blow 15 Pipe 20 Cavity type | mold 21 Suction hole 22 Clamp 30 Core type | mold 31 Core 32 Gas body inlet 33 Gas body outlet 34 Gas body flow path 35 Cavity 35a Cavity surface 35b Cavity surface corner 40 Decorative film 40a Decorative film 40b in front of the injection mold Die base film 40c Pattern part 41 Decorative film Front surface 42 Back surface 43 of the decorative film Corresponding portion of the corner of the resin molded product of the decorative film

Claims (4)

An injection mold consisting of a cavity mold and a core mold;
A gas supply means that blows out toward the decorative film inserted between the cavity mold and the core mold,
The in-mold molding is characterized in that the gas outlet is a corner portion of a resin body to be injection-molded and is disposed so as to be discharged toward a decorative film portion corresponding to the decorative portion. apparatus.   An in-mold molding apparatus characterized in that the gas supply means gasifies a fluid generated using a supercritical fluid generator or the like and adjusts the fluid to a predetermined temperature.   3. The in-mold molding apparatus according to claim 1, further comprising a blowing gas blowing unit that blows a gas onto the decorative film before the decorative film is inserted between the cavity mold and the core mold. .   A step of inserting a decorative film between the molds of the cavity mold and the core mold, and a step of blowing a permeable gas onto the decorative film corresponding to the position to be decorated at the corner of the resin body to be injection molded And a step of injecting a molten resin.

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