Soluble polymer and fibre-based closure compatible with paper recycling

Overview

Aquapak's patented Hydropol polymer offers a sustainable alternative to traditional plastics for closures used on paper-based packaging. Hydropol is water-soluble, marine-safe, biodegradable, and compostable, and does not produce harmful microplastics. Critically, it has already been proven fully compatible with paper recycling processes, making it well suited for fibre-based packaging applications such as food and beverage containers.

This project focuses on developing a closure (cap) for paper packaging using Hydropol, potentially loaded with wood fibre to reduce polymer content while adding value to the paper mill supply chain. The material can be processed using standard injection moulding equipment, enabling straightforward manufacturing integration.

Technical specifications

• Base material: Hydropol, a proprietary polymer based on PVOH chemistry with unique end-of-life characteristics
• Injection moulding compatible: Can be processed on existing machinery into traditional cap designs
• Wood fibre loading: Research underway to determine maximum fibre loading while retaining functional performance
• Barrier properties: Excellent oxygen transmission rate (OTR); novel solutions under investigation for water vapour transmission rate (WVTR)
• Hydrophilic nature: Highly compatible with food fibre and cellulose-based substrates
• End-of-life profile: Fully compatible with paper recycling, biodegradable, compostable, and marine-safe

Technology readiness level

Hydropol has undergone extensive internal and third-party testing, including barrier property assessment (Camden, Mocon, Industrial Physics), paper recycling compatibility (Test Tech), and marine safety and toxicity validation (Heriot-Watt University). Fate in paper mills and water effluent treatment plants has been evaluated with 360 Eco and AquaEnviro. Initial customer trials for injection moulding have been conducted.

The next phase involves pilot-scale compounding of wood fibre into Hydropol, rheology and injection moulding testing, barrier performance assessment, and research into novel WVTR solutions. Scaling of injection moulding capability with third-party partners is also planned. The technology is at an advanced development stage, transitioning from lab validation toward pilot and commercial-scale production.