Angular Resin Container Scallop Height Mold Release

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Solution Overview

Problem

Thin resin containers, especially angular ones, face deformation issues during mold release due to high mold release resistance and air pocket formation, which compromises their luster and transparency, and existing surface treatments to address these issues deteriorate their appearance.

Innovation Solution

An angular resin container with a thickness of 0.5 mm or less and a blow molding die featuring a scallop height of 3 to 30 μm on the cavity surface, with processing marks 0.1 to 1.0 mm apart, to reduce mold release resistance without post-cutting surface treatments, ensuring excellent luster and transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If the resin container is thinned to decrease raw material usage, then production cost and waste are reduced, but the container strength decreases and it becomes easily deformed during mold release

Engineering Contradiction:
Improveraw material resinVSAvoidcontainer strength
Core Design Contradiction:
Loss of substanceVSStrength

Solution Approach 1:

The cavity surface is selectively roughened only in specific regions where the container wall thickness is minimal (such as corner surfaces and ridge lines), while other areas maintain mirror-finished surfaces. This localized surface treatment reduces mold release resistance at critical thin sections without affecting the overall container strength or requiring universal surface roughening

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cavity surface roughening is performed in advance during die manufacturing, creating protrusions that will later facilitate air release and reduce mold release resistance when the thin container is formed, preventing deformation during the molding process

Inventive Principle:
Principle #10Preliminary action

2Illumination intensity

If the cavity surface is mirror-finished, then the container has good luster and transparency, but air remains between the container and cavity surface forming pockmark-like air pool marks

Engineering Contradiction:
Improveluster and transparencyVSAvoidair pool marks
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The cavity surface is selectively roughened only in specific regions where the container wall thickness is minimal (such as corner surfaces and ridge lines), while other areas maintain mirror-finished surfaces. This localized surface treatment reduces mold release resistance at critical thin sections without affecting the overall container strength or requiring universal surface roughening

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Protrusions are formed on the cavity surface at predetermined positions, acting as intermediaries to facilitate air release between the container and cavity surface during molding, thereby preventing air pool marks while maintaining good appearance in non-protrusion areas

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If sand blasting is conducted on the cavity surface to release air, then air pool marks are prevented, but the container appearance is deteriorated with reduced luster and transparency

Engineering Contradiction:
Improveair pool marksVSAvoidluster and transparency
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The cavity surface is selectively roughened only in specific regions where the container wall thickness is minimal (such as corner surfaces and ridge lines), while other areas maintain mirror-finished surfaces. This localized surface treatment reduces mold release resistance at critical thin sections without affecting the overall container strength or requiring universal surface roughening

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of applying sand blasting uniformly across the entire cavity surface, the invention applies surface roughening only partially at specific locations where it is most needed for air release and mold release resistance reduction, thereby achieving the beneficial effect with minimal impact on overall appearance

Inventive Principle:
Principle #16Partial or excessive action

4Strength

If the cavity surface is roughened to reduce mold release resistance, then thin container deformation is prevented, but the container luster and transparency are significantly deteriorated

Engineering Contradiction:
Improvemold release resistanceVSAvoidluster and transparency
Core Design Contradiction:
StrengthVSIllumination intensity

Solution Approach 1:

The cavity surface is selectively roughened only in specific regions where the container wall thickness is minimal (such as corner surfaces and ridge lines), while other areas maintain mirror-finished surfaces. This localized surface treatment reduces mold release resistance at critical thin sections without affecting the overall container strength or requiring universal surface roughening

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of applying sand blasting uniformly across the entire cavity surface, the invention applies surface roughening only partially at specific locations where it is most needed for air release and mold release resistance reduction, thereby achieving the beneficial effect with minimal impact on overall appearance

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS9382029B2Angular resin container and blow molding die
Publication Date: 2016.07.05 TOYO SEIKAN GRP HLDG LTD

AI summary

Provided are an angular resin container, which while being thin, retains excellent appearance in respect of luster, transparency or the like, as well as a blow molding die for subjecting the container to biaxial stretch blow molding. Biaxial stretch blow molding is conducted with a blow molding die having a scallop height for the surface of the blow molding die, that corresponds to the side wall part of the body part of the angular resin container, of 3 to 30 μm, thereby to obtain an angular resin container having a thickness of the body part of 0.5 mm or less and in which a horizontally-directed processed part having a depth of 3 to 30 μm is formed on the outer surface of the side wall part of the body part.