Recycled HDPE Tube Composition for Hot Tack and Seal Strength
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Solution Overview
Problem
Post consumer recycled HDPE polymer compositions face challenges with brittleness, poor seal strength, and environmental stress crack resistance, making it difficult to recycle and reuse in the same form, especially in high-speed packaging operations where hot tack properties are critical.
Innovation Solution
A composition comprising 80% to 95% post consumer recycled resin and 5% to 20% adhesion additives, such as ethylene alpha-olefins copolymers or metallocene linear polyethylene, along with optional antioxidants and color masterbatches, is used to enhance toughness, seal strength, and hot tack properties, facilitating the recycling and reuse of HDPE tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If post consumer recycled HDPE resin is used to manufacture tubes, then environmental sustainability is improved, but the material exhibits poor toughness, brittleness, and seal strength
Solution Approach 1:
The patent creates a composite material system by blending post consumer recycled HDPE resin with adhesion promoters (ethylene-alpha olefin copolymer or metallocene polyethylene) in specific ratios (70:30 to 90:10). This composite approach combines the sustainability benefits of recycled material with the enhanced adhesion and toughness properties of the additive polymers, resolving the contradiction between environmental sustainability and mechanical strength
Solution Approach 2:
The patent modifies the compositional parameters of the recycled HDPE by controlling the ratio of recycled resin to adhesion promoter within specific ranges. By adjusting these parameters, the material achieves optimal balance between sustainability (higher recycled content) and performance (adequate seal strength and toughness), particularly achieving hot tack strength ≥15 N/mm at sealing temperatures of 120-150°C
2Stability of the object's composition
If post consumer recycled resin is used, then recyclability is improved, but hot tack properties and seal strength deteriorate
Solution Approach 1:
The adhesion promoter acts as an intermediary substance that bridges the compatibility gap between different polymer components in the recycled mixture. It mediates the interfacial adhesion between recycled HDPE chains, enabling effective stress transfer and achieving reliable hot tack properties (≥15 N/mm) while maintaining the recyclability of the overall composition
Solution Approach 2:
By controlling the concentration of adhesion promoter within 10-30% by weight and the recycled resin content within 70-90% by weight, the patent optimizes the thermal and mechanical parameters of the material. This parameter optimization ensures that the material achieves sufficient hot tack strength for high-speed sealing operations while maintaining compositional stability for recyclability
3Loss of energy
If post consumer recycled HDPE is used, then energy conservation is improved, but environmental stress crack resistance worsens
Solution Approach 1:
The patent develops a composite formulation where the adhesion promoter network acts as a crack-arresting phase within the recycled HDPE matrix. This composite structure dissipates stress concentrations that would otherwise propagate as environmental stress cracks, improving ESCR performance while maintaining the energy conservation benefits of using recycled material
Solution Approach 2:
The patent optimizes the compositional parameters to achieve a percolating network of adhesion promoter that provides crack resistance. By maintaining adhesion promoter content at 10-30% and recycled resin at 70-90%, the material achieves sufficient environmental stress crack resistance (break time ≥10 hours in 0.1M NaCl solution) while conserving energy through recycled material utilization
Data Source
AI summary
The present disclosure relates to a post consumer recycled polymer composition comprising: 80% to 95% (w/w) of a post consumer recycled resin; and 5% to 20% (w/w) of at least one additive. The present disclosure further relates to a laminate comprising: an outer layer of a post consumer recycled polymer composition; a middle layer of post consumer recycled polymer composition; and an inner layer of virgin resins. The present disclosure also relates to a process for manufacturing tubes comprising: extrusion of post consumer recycled polymer composition comprising 80% to 95% (w/w) of an post consumer recycled resin; and 5% to 20% (w/w) of at least one additive, through a circular slit to form a long cylindrical hollow pipe; slicing the long cylindrical hollow pipe to form tube sleeves; forming tube shoulder and neck; and attaching the tube shoulder and the neck to the tube sleeves to obtain a tube.