Blow-Molded Container Base with Angled Heel and Rounded Edges

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Solution Overview

Problem

Plastic containers used in hot fill, pasteurization, and retort processes often deform significantly under high temperatures and pressures, leading to shape distortion and increased risk of fracturing, which affects label application, stacking, and oxygen barrier integrity.

Innovation Solution

A base structure for blow-molded containers featuring an annular sidewall with a flat bottom, an angled annular support heel, and rounded edges, made from materials like polyester resin or polypropylene, designed to withstand thermal processes without significant deformation, maintaining perpendicularity and structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional base designs are used in blow-molded containers, then manufacturing is simpler, but the containers deform significantly (3-5° lean) during thermal processes

Engineering Contradiction:
Improvecontainer perpendicularityVSAvoidbase structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies curvature by rounding the edges between the sidewall and heel, and between the heel and bottom portion, with radii of curvature of 1.0-14.0 mm. This curvature distributes stress more evenly during thermal processing, preventing the sharp corners from acting as stress concentration points that would cause deformation and leaning of the container.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the base structure, specifically the heel angle (15°-46°) and the radii of curvature (1.0-14.0 mm). These parameter changes optimize the base's ability to withstand thermal stress while maintaining structural integrity and minimizing container deformation during hot-fill and retort processes.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If standard heel angles are used, then manufacturing is easier, but the container cannot withstand high temperatures and pressures without distortion

Engineering Contradiction:
Improvethermal process resistanceVSAvoidmolding complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent specifies a heel angle range of 15°-46° and radii of curvature of 1.0-14.0 mm, optimizing these geometric parameters to balance thermal resistance with manufacturability. The angled heel structure provides structural support against thermal stress while remaining compatible with standard blow-molding processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By incorporating rounded edges with specific radii of curvature, the design distributes thermal and mechanical stresses more effectively during high-temperature processing, enhancing the container's ability to withstand retort and hot-fill conditions without excessive molding complexity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If the container is subjected to retort processes, then sterilization is achieved, but the container shape distorts and retains distorted shape after cooling

Engineering Contradiction:
Improvesterilization capabilityVSAvoidcontainer shape retention
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The rounded edges with radii of 1.0-14.0 mm prevent stress concentration at sharp corners during thermal cycling, allowing the container to withstand retort sterilization temperatures and pressures while maintaining its shape and returning to its original form after cooling.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The optimized heel angle (15°-46°) and curvature radii create a base structure that is sufficiently rigid to resist deformation during high-temperature sterilization, enabling the container to maintain perpendicularity and shape retention through the thermal process cycle.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If base deformation occurs, then thermal processing can proceed, but label application and stacking ability are compromised

Engineering Contradiction:
Improvelabel application qualityVSAvoidthermal processing throughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The curved transition zones in the base structure prevent deformation that would compromise label application surfaces and stacking interfaces, ensuring that containers maintain the geometric precision needed for quality labeling and stable stacking while still undergoing thermal processing.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The specific heel angle and curvature radii parameters ensure that the container base remains stable and perpendicular during thermal processing, providing flat surfaces for label application and proper geometry for stacking, thereby maintaining both quality and productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3024741B8Base for hot-fill plastic containers
Publication Date: 2018.06.27 GRAHAM PACKAGING CO LP

AI summary

A base structure for a blow-molded container (10) having an annular sidewall (6) and a central longitudinal axis (100), the base structure comprising: a bottom portion (2); an annular support heal positioned between the sidewall (6) and the bottom portion (2), wherein the annular support heal is angled inwardly at an angle θ of from about 15° to about 46° relative a plane extending from the sidewall (6); and a first rounded edge (4) between the sidewall (6) and the annular support heal and a second rounded edge (5) between the annular support heal and the bottom portion, wherein each of the first and second rounded edge has a radius of curvature of from about 1.0 mm to about 14.0 mm, and wherein the blow-molded container comprises a material selected from the group consisting of polyethylene terephthalate and polypropylene.