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Scottish Plastics and Rubber Association Scottish Plastics and Rubber Association

SPRA Technical Meeting on Materials and Design

Tony Shelmerdine, MonoSol Ltd

A total of 34 members and guests turned out for the evening meeting at Edinburgh Napier University on 8th February 2011.  The first topic - Materials - was covered by a very interesting presentation from Tony Shelmerdine of Monosol Limited, who described the grades and applications of water soluble materials based on poly(vinyl alcohol). PVOH should not be confused with PVA poly(vinyl acetate) which is widely used as wood glue.  Indeed poly(vinyl alcohol) is manufactured by partial or complete hydrolysis of poly(vinyl acetate). Tony showed how by controlling the structure of the PVOH, films can be produced that are soluble in cold water or only soluble in hot water, leading to a range of applications such as laundry bags, detergents, toilet blocks, fish bait bags and transfer printing. Being fully biodegradable, PVOH has potential for other 'green' products.
Product Compatibility Testing is offered as a paid for service. Typically a 42 day test period at various climatic conditions in secondary packaging is carried out with ambient and "accelerated ageing tests" to check physical properties & solubility after exposure. "Green issues" were a significant part of the presentation and the discussion that followed.
How "Green" is PVOH?
Compostable? - Yes, but not to EN13432 standard - needs seeding & time - cannot be certified as "compostable"
Biodegradable? - Yes, in solution with the presence of water. Well established in effluent sewage systems where mechanical action speeds up the process. Breaks down into carbon dioxide and water.
Biodegradation of PVOH involves at least 55 species of micro organisms and will degrade in 20-28 days in a wastewater treatment facility with low toxicity in fish.
What is in the future?
Convenience end use film continues to grow in demand with  MonoDose and Packaging. The drivers are:
Environmental Green movement; Waste minimisation - legislation; and brand & company visions. Technological advances in film processing include:  co-extrusion; laser sealing and cutting; and Medical applications. Other developments include injection moulded gelatin capsule alternative, and even rotational moulding.   

Electricity, water and gas metering monitor , designed by Shore Design
In the second presentation, entitled 'Returning Investment throughout the Design Process', James McLusky and Allan McDougall explained how Shore Design view the key stages of a design project as set-up, concept design, engineering development, prototype and development and production support. Although it may have seemed from the outset that there was no connection between the two presentations, there was in fact.  The case studies presented were all for 'Green' products: the Smart Electricity Meter, the Evohome temperature controller and EWGECO, the electricity, water and gas metering monitor. These products, all designed by Shore Design, were used to illustrate the stages of design projects.  The discussion that followed included such topics as - "How did/do you get into design as a career". 

Colin Hindle, SPRA Education Officer   March 2011

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Technical Info from SPRA

  • Materials Thermoplastics, Thermosets, Elastomers, Additives.
  • Processes Moulding, Extrusion, Thermoforming, Ancillaries.
  • Design Product, Mould, CAE, Testing.
  • Applications Healthcare, Packaging, Electronics, Other Markets.
  • Environment Waste, Recycling, Sustainability, Legislation, Energy.
  • Business Issues Network, Seminars, Competitiveness, Innovation, Regulation.