Welded Plastic Bag With Corner Welds for Shape Retention

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Solution Overview

Problem

Conventional containers for collecting and transporting recyclable goods, such as empty cans or bottles, are inefficient due to space requirements, moisture sensitivity, and generation of cardboard waste, and lack the ability to maintain shape and prevent odor and insect ingress.

Innovation Solution

A flexible welded plastic container bag with a quadrangular cross-section, corner welds for rigidity, and support welds to prevent barreling, allowing it to stand alone and be stacked, while being liquid and air-tight when closed, made from thermoplastic film that can be produced in high volumes at low cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If rigid bins or containers are used for collection, then structural support and shape retention are improved, but storage space efficiency deteriorates and cardboard waste is generated

Engineering Contradiction:
Improveshape retentionVSAvoidstorage space efficiency
Core Design Contradiction:
ShapeVSVolume of moving object

Solution Approach 1:

The patent uses a flexible plastic bag with corner welds and support welds to create a container that can stand upright and retain its box-like shape without requiring rigid cardboard boxes or bins. The flexible film with strategic welding provides both shape retention and space efficiency, eliminating the need for rigid supporting structures.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention extracts the essential function of shape retention from rigid cardboard boxes and implements it through a flexible plastic bag with corner welds. This separates the shape-retention function from the rigid structure, allowing the container to be both flexible and structurally sound.

Inventive Principle:
Principle #2Taking out (Extraction)

2Volume of moving object

If thin plastic film liners are used, then storage space efficiency is improved, but structural integrity and stacking ability deteriorate

Engineering Contradiction:
Improvestorage space efficiencyVSAvoidstructural integrity
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent employs a thin plastic film bag that maintains structural integrity through corner welds extending from the base to a predetermined height and support welds connecting opposite side walls. This combination provides the necessary strength for stacking and handling while retaining the space efficiency of flexible film.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention creates a composite structure by combining thin plastic film with welded joints (corner welds and support welds). The welded areas provide structural reinforcement while the majority of the bag remains thin and flexible, achieving both strength and space efficiency.

Inventive Principle:
Principle #40Composite materials

3Strength

If corner welds are added to provide rigidity, then structural integrity is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies corner welds to flexible plastic bags to provide structural support. The welds are strategically placed at corners and extend to a predetermined height, providing rigidity where needed while keeping the rest of the bag flexible and simple to manufacture.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention applies welding only at specific locations (corners and support positions) rather than throughout the entire bag. This localized welding provides structural integrity at critical points while keeping the overall manufacturing process simple and the majority of the bag material unwelded and flexible.

Inventive Principle:
Principle #3Local quality

4Reliability

If the bag is made fully liquid-tight with welding, then leakage prevention is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveleakage preventionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a flexible plastic film bag with selective welding to achieve liquid-tight properties. The welding is applied at corner joints and support weld locations to prevent leakage at critical stress points while keeping the rest of the bag simple and cost-effective to manufacture.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention implements liquid-tight properties locally at welded joints (corner welds and support welds) rather than welding the entire bag. This provides adequate leakage prevention at critical areas while maintaining manufacturing simplicity and cost-effectiveness for the majority of the bag surface.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3109179B1Welded bag, roll, use and method of manufacturing
Publication Date: 2019.06.12 TRIOPLAST NYBORG AS
  • EP3109179B1 patent drawingFigure 1
  • EP3109179B1 patent drawingFigure 2a~2c
  • EP3109179B1 patent drawingFigure 3a~3b

AI summary

A welded plastic container bag (100) for collection and transport of goods, wherein said bag in an upright deployed state has a substantially quadrangular horizontal cross section with a substantially quadrangular base (104) and four side walls (106a-d), and wherein adjacent side walls are connected by a corner weld (112) extending in a direction substantially perpendicular to the base, from the corners of the base substantially up to a predetermined fill level of the bag. A method of manufacturing such a bag, and to the use of such a bag for collection and transport of bulk products.