Elastic Drawstring with Polypropylene Blend for Bag Securing
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Solution Overview
Problem
Existing plastic bags used as liners for waste receptacles face challenges in securing the bag to the receptacle, as they tend to slide down due to the weight of materials inside, and existing elastic solutions are either difficult to manufacture or pose safety hazards, especially when in a highly stretched state.
Innovation Solution
A closed loop elastic drawstring formed from a mixture of linear low-density polyethylene and polypropylene, with perfed notches at the top of the bag that break away to expose the ends, allowing the drawstring to be stretched around the receptacle and then sealed to provide a stronger holding force without closing the bag prematurely, also serving as a tie to secure the bag when removed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastic loop is used to hold the bag at the top of the receptacle, then the bag can be secured and closed automatically when removed, but the elastic band must be in a highly stretched state which is difficult and expensive to manufacture and creates safety hazards
Solution Approach 1:
The elastic drawstring is pre-formed into a closed loop configuration during manufacturing, eliminating the need to assemble stretched ends later. This preliminary formation allows the elastic to be installed in a relaxed state rather than highly stretched, reducing manufacturing difficulty and cost while maintaining the automatic closing function.
Solution Approach 2:
The invention changes the physical state parameter of the elastic drawstring from a highly stretched state to a relaxed state during installation. By forming the closed loop in a relaxed state and allowing it to stretch only when activated by pulling the hem, the elastic maintains its elastic properties and reduces manufacturing complexity.
2Reliability
If an elastic band is used to hold the bag on the receptacle, then the bag can be secured, but the band cannot be used as a drawstring to close the top of the bag when filled
Solution Approach 1:
The elastic drawstring is designed to perform multiple functions: it serves as both the holding mechanism to secure the bag to the receptacle and as the drawstring to close the bag when filled. The closed loop configuration allows it to function in both capacities without requiring separate components.
Solution Approach 2:
The invention merges the holding band function and the drawstring closing function into a single elastic drawstring component. This unified design eliminates the need for separate elastic bands and drawstrings, providing both bag securing and bag closing capabilities through one element.
3Force
If the drawstring circumference is smaller than the bag circumference, then the drawstring can be stretched to hold the bag, but existing non-elastic drawstrings cannot provide sufficient holding force
Solution Approach 1:
The elastic drawstring is constructed from a composite material system combining elastomeric polyolefin material (providing elastic properties) with polypropylene (providing strength and stiffness). This composite structure enables the drawstring to stretch sufficiently to provide holding force while maintaining the tensile strength needed to support the bag weight.
Solution Approach 2:
The invention changes the material parameters of the drawstring by incorporating elastic materials that can undergo reversible deformation. The elastomeric polyolefin component allows the drawstring to stretch and contract, providing the necessary holding force through elastic recovery while the polypropylene component maintains structural integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a stronger holding force and improved tensile yield, ensuring the bag remains securely in place and can be easily closed without the risk of accidental closure, enhancing safety and manufacturing efficiency.
Implementation Method 1
The drawstring is preferably formed from a thermoplastic rubber-linear low density polyethylene blend
Implementation Method 2
The drawstring is preferably formed from a thermoplastic rubber-linear low density polyethylene blend
Data Source
AI summary
An elastic drawstring for use in a plastic liner bag is disclosed. The drawstring is elongated and then relaxed to secure the top of the bag to a receptacle and subsequently used to close the bag when filled. The drawstring is formed from an elastomeric polyolefin, preferably a linear low density polyethylene, and contains material comprising polypropylene. The polypropylene addition provides the drawstring with improved modulus or stiffness and improved tensile yield. Improving these properties gives the drawstring a stronger holding force for maintaining the bag in the receptacle and in a closed position when the bag is removed from the receptacle. In addition, the top of the bag has perfed notches at each side that break away to expose the ends of the elastic drawstrings when the consumer stretches the drawstrings around the top of the receptacle. These perfed notches allow for easier manufacturing of the bag.