Injection molding method for in-mold decoration

Abstract

The invention belongs to a method for the injection molding of an in-mold decoration (IMD for short). The method for the injection molding of the in-mold decoration is characterized by comprising the following steps: 1) performing high pressure forming on transparent base materials to form the needed shape; 2) filling the formed transparent base materials into a die cutting mold and cutting away redundant edges; 3) filling the transparent base materials into a mold cavity, injecting thermoplastic resin to the surfaces of the transparent base materials to form patterns and obtain the transparent base materials with the patterns, and using the injecting process to replace ink printing; and 4) injecting out the thermoplastic resin again to obtain the product. The method has the advantage that the contour lines of the patterns formed on the surfaces of the transparent base materials by the injected thermoplastic resin can well superpose with the contour line formed by the high pressure forming and cannot generate misplacement. With the method, the produced products can obtain high rate of finished products and beautiful appearance.

Description

technical field [0001] The invention belongs to the method of In-Mold Decoratiom (IMD for short). Background technique [0002] In the current IMD technology, the general process is to print patterns on a transparent substrate such as a film, then place the film in a mold for high-pressure molding, then cut off the edge of the formed film, and finally inject a thermoplastic resin to form a product. For example, the Chinese invention patent application with the application number 200610028915.9 under the name of the applicant in this case discloses a preparation process for in-mold decorations, including the following steps: [0003] 1], on the surface of the printed film, the decorative pattern is printed with ink; [0004] 2], high-pressure forming the printed film into the required shape, and cutting off the excess edges; HDVF high-pressure forming machine is used for high-pressure forming, and its process parameters are upper and lower heating temperatures of 280 ° C ~ 3...

AI Technical Summary

Problems solved by technology

[0006] In the actual production process, when the outline of the pattern printed on the surface of the substrate that needs to be transparent overlaps with the high-pressure molding line formed by high-pressure molding, it is often difficult to achieve

The products manufactured in this way will have misalignment between the contour line or structure line of the surface (that is, the high-pressure forming line formed by high-pressure forming) and the contour line of the printed pattern, which will affect the appearance.

Even if some products do not require the outline of the pattern to overlap with the high-pressure molding line, the pattern that was originally designed to be symmetrical about a certain line (such as the center line of the product surface) will become asymmetrical due to the dislocation of the pattern, which will affect the appearance.

The reason for this problem is that the printed film is deformed due to heat during high-pressure molding, which causes the pattern on the film to deform and move.

Therefore, the positioning after molding is not accurate, and the high-pressure molding line does not match the actual size requirements of the printed pattern, resulting in misalignment between the printed outline and the high-pressure molding line

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