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Development of a new recyclable long life co-injected high barrier packaging for food applications, with broad design possibilities and reduced manufacturing costs

Final Report Summary - COBAPACK (Development of a new recyclable long life co-injected high barrier packaging for food applications, with broad design possibilities and reduced manufacturing costs)

Executive summary:

The main objective of the project is to develop a new high-barrier long-life, low-cost, recyclable packaging through a special injection moulded process (co-injection) specially addressed to applications in food sector. The core of the new packaging has been made of a renewable material (starch) and it has met the required physic-mechanical and chemical properties for its optimum production and use. Thanks to its design possibilities, it could open new markets for products where other packaging materials are used, such as glass or metal.

The main innovations claimed in COBAPACK are:

- New recyclable multilayer structure: Current multilayer packages are not recycled because the recycling implies a delamination process which is difficult, expensive and with high environmental impact (use of organic solvents). The new co-injected structure is easily delaminated in a standard plastic waste plant, where starch dissolved in water could be used for compost and the skin layer (polypropylene, high-impact polystyrene (PP, HIPS)) is recycled.

- Co-injection process: It is a little-known process. Nowadays its application is focused on thick parts using virgin and recycled material. The project knowledge helps to increase its possibilities, for example, little scrap production, savings in processing costs, design capabilities, core / skin thickness ratio, etc. The project objectives could be extrapolated to other sectors with similar requirements (cosmetic, pharmaceutical and chemical sectors).

- An optimised destructurised starch for co-injection process: Destructurised starches are commercially available. However, due to the special specifications of this project, to develop a new starch grade material specific for the application will be necessary. Parameters such viscosity, barrier and thermal properties have been taken into account.

- Compatibilisation of starch with non-polar polymer: To determine the suitable compatibilising additives with the aim to join both materials.

- Broad design possibilities: Consumers and retailers buy the product based on the package. Nowadays, the customers demand packaging with innovative appearance, distinctive, smaller units, user's friendliness. The co-injection technology has allowed wider freedom in design.

All the non-confidential information generated so far under the project can be found in COBAPACK website, in the open area.

The new technology developed in the COBAPACK project may have a significant impact on the plastic industry; improving the current plastic food packaging alternatives and offering a new range of environmentally friendly packages. True industrial impact will require further investment, aimed to optimise the actual scale-up of the compound, co-injection and recycling processes making them suitable for a continuous fabrication stage.

Although the project's development is aimed at specific food packaging (according to the end-user business field), the compound developed (under process of patent application) plus the improvements / adjustments in the co-injection technology which has given the best results, will be able to be applied to other packaging sectors, provided that the specific requirements of each food packaging application can be fulfilled.

Project context and objectives:

Packaging plays a vital role in any modern integrated product supply system. It does not only protect a product integrity and properties from the production line to the consumer (impact on health and safety), but also facilitates production, distribution and storage. Packaging technology is currently making huge strides in the development and application of new products and processes. For high-properties (protection from environment, mechanical and thermal resistance, oxygen and moisture barrier, etc.) demanding applications, multilayer sheets are employed. Pâtés, pre-cooked meals, cheese, pets food, canned fruit, soups, fresh pasta, meat, fruit salads, pizza, ice cream, margarine, bakery and patisserie trays are just a few of the food related applications. Other non-food applications include toiletries, chemical and pharmaceutical products. The two main processing categories for producing multi-layer structures are cast film co-extrusion and lamination process. Due to its high cost, the latter is used only for flexible packaging (not for thermoformed package). Mostly, this multilayer package is made by a complex two-step process: co-extrusion followed by thermoforming process. This production technology, carried out mainly by small and medium-sized enteprises (SMEs) in the European Union (EU), has the following main problems:

(1) Co-extrusion (multilayer structures):
(a) synthetic polymers (mainly EVOH) used as inner layer are very expensive and chemically incompatible with the other layers preventing post-used packages recycling;
(b) scrap production reaches at least 10 % (sheet edges called neck-in).

(2) Thermoforming (to process the sheet into shapes):
(a) high scrap production (up to 40 %) due to trims, especially in oval and round forms, and processing problems (high technical complexity, very long time of fine tuning, limited choice of materials) which derive from co-extruded sheets crystallinity;
(b) design limitations: neither complex forms nor uniform thickness, and no high depth of draw ratio are allowed.

In order to solve the above mentioned problems, COBAPACK innovative approach has consisted on:

(1) Using destructurised starch (a by-product with low cost and soluble in water), to allow the complete separation of both materials, skin (PP or HIPS) and core (starch), thus recycling 100 % the package's skin.
(2) Using a co-injection process, which is a one-step process with minimum scrap losses, savings in energy consumption, broad design flexibility, wide range of materials processing, high-production rates, repeatability within tolerances and reduction in waste disposal costs.

Detailed objectives: In order to achieve the main objective of the project, i.e. to develop a new high barrier long life, low cost, recyclable packaging through a special injection moulded process (co-injection), several specific objectives were defined, such as:

(1) to increase the thermal resistance of the current thermoplastic starches by a 30 % using synergic blends of low molecular weight and polymeric plasticisers in order to reach the requirements imposed by pasteurisation, retort and microwave heating processes;
(2) to reduce the viscosity of current thermoplastic starch by a 20 % using synergic blends of low molecular weight and polymeric plasticisers;
(3) to develop a new high barrier, long life, recyclable, low cost food package which can substitute the current non-recyclable multilayer structures with synthetic high barrier materials (EVOH, PVDC, PA);
(4) to take advantage of the co-injection technique benefits compared to thermoforming:
(a) industrial scrap reduction (90 % in weight): neither sheet edges (neck-in) nor trims in oval and round shapes;
(b) process in just one step, instead of two steps (co-extrusion + thermoforming);
(c) freedom of design, more possibilities for 'tailor-made' packages;
(d) wider processing window: reduction in set-up mechanisms and adjustments.
(5) the package can be recycled in a standard recycling installation as a standard monolayer plastic package. The waste water from this recycling process can be threaded in a biological wastewater treatment plant to remove the organic matter;
(6) to reduce the package cost by a 14 %, taking into account the full process, maintaining all the current thermoformed packages requirements;
(7) new co-injected package must fulfil the related regulatory requirements;
(8) to develop an understanding of the morphological and interface characteristics of the new package made up of non-chemically modified starch and commodity plastic materials such as PP or HIPS, in a core-skin structure obtained through the co-injection process;
(9) to study and analyse the effective behaviour of the starch (core material) during the food processing and products' life and its influence on foodstuff preservation;
(10) to overcome the lack of technical experience that exists about the co-injection process in thin wall parts (the co-injected package thickness will be around 1.5 mm versus the current 5 mm, in the best cases) and in the combination of renewable and non-biodegrable materials.

Finally, besides technical objectives, COBAPACK project aims at improving the EU plastic industry competitiveness, in particular, but not limited to, companies focused on the co-injected packaging market. Although often highly ambitious in their outlook, the vast majority of these SMEs lack the resources to develop innovative materials and methods of work.

The achievement of the objectives listed above may result in an increase of the competitiveness of the participating SMEs which represent the different types of SMEs involved in the co-injected packaging supply chain:

- Renewable materials producers will have an increase in sales in the new market. Currently, native starch has food industry, paper and paperboard, textile and chemical products as the main end-user markets. On the other hand, chemically modified starch (NOVAMONT, DAICEL) is used in mulch and film packaging applications. However, destructurised starch (native starch and plasticisers) which is COBAPACK base material, has only been used in applications where low melt strength, low water resistance and low surface quality are not a drawback, such as loose fill chip packaging. In this case, the destructurised starch in higher added value applications, taking advantage of its high oxygen barrier properties, will be used.

- Mould manufacturers will have an increase in moulds sales since a new market will be opened. Furthermore, new mould designs will be needed to satisfy new plastic packaging shapes which will be obtained only through co-injection process.
- Co-injectors:
(a) will produce a more innovative product (freedom of design) than the current high barrier plastic thermoformed packaging;
(b) will increase their volume of business, product range and will reduce costs, therefore increasing their turnover.

- Plastic recyclers will increase their volume of business since the profitable PP / HIPS current market will be strengthened due to the additional quantity of these commodity plastics to be recycled coming from the new packaging developed (from its skin material).
- End user will improve their public image by using the environmentally friendly packaging developed, helping them to increase their business and saving in costs i.e. cheaper package.

As a summary

Specific innovations of the project are:

(a) obtaining thermoplastic starch, proven suitable for co-injection process by means of destructurisation, using special additives;
(b) manufacturing of co-injected package with asymmetric and final geometry using as a core, the thermoplastic starch and, as a skin, the commercial thermoplastic materials used for this kind of applications;
(c) definition of packaging geometry to build a new mould and co-injection system to fulfil the end-user requirements;
(d) good properties in the recycled PP. The recycled PP obtained could be used for different applications;
(e) new mould and hot runner system have been manufactured with the new package design;
(f) using Kortec technology, it has been possible to obtain a package in good conditions made up of PP as skin and a thermoplastic starch as core. It has been proved that if the final package contains less amount of starch, it can still withstand the retort process without losing oxygen barrier properties, thus fulfilling all the end-user requirements.

Expected final results:

All the expected final results foreseen initially were achieved under the scope of the project (pre-industrial level, i.e. pre-competitive project-setting up of the industrial conditions), at the end of reporting period 2.

(1) New high barrier long life co-injected food package with recyclable skin/biodegradable core, broad design possibilities Achieved. New high barrier co-injected packages, potentially capable of replacing the thermoformed ones (by using a specific co-injection technology, KORTEC one, tested in parallel to the COBAPACK one) were obtained. Those new co-injected packages with the new compound developed showed physic-mechanical and thermal properties in accordance with HEINZ requirements.

(2) Adaptation of the co-injection process needed to obtain the new lower cost long life food packaging with 100 % recyclable skin, using renewable by-product starch in the core (retort and pasteurisation food applications). Achieved. During P2, the co-injection process was optimised at pilot plant level and then tested through two different ways at pre-industrial level. A comparison of those 2 types of co-injection processes was carried out. It was concluded that the simultaneous one is better than the sequential one: less starch thickness, withstand the retort, good barrier properties.

(3) Destructurised starch for co-injection process. Achieved. The development of a new starch grade material specific for HEINZ´s application, inside the new co-injected packages through simultaneous process was accomplished.

(4) New grades of PP or HIPS materials suitable for the new co-injected structure. Non applicable. During period 2, it was checked that even by improving HIPS behaviour, the co-injected packages with this skin material (PP+ Talc, simulating HIPS behaviour) did not provide acceptable results as for the PP co-injected packages. That is why HIPS research line was ruled out, and all the optimisation efforts were focused on the PP layer co-injected packages. Please note that it was found that the best was of proceeding was to include all the material modifications in the core layer (starch formulation). Therefore, typical commercial PP grades are chosen to be part of the skin layer.

In the end user facilities have been carried out a preliminary trials in order to evaluate the behaviour of the co-injected packages.

Potential impact:

Dissemination activities

It is essential to highlight that a great deal of dissemination activities have been activated and completed during the development of COBAPACK. The project information has been disseminated via three channels:

(a) by partners within their organisations (e.g. internal newsletters, meetings, workshops, seminars, training courses, etc.);
(b) by partners during external events (e.g. fairs, conferences, networking events, etc.);
(c) by partners using media across Europe (e.g. press release, Internet, specialised magazines, etc.).

The use of various channels (internal and external) and methods (mainly written and online) assured an optimal contribution of coverage, visibility and most important - setting up the scene for better market acceptance in the near future.

The activities in the dissemination plan covers different audiences and channels depending on the type of information to be disseminated, in order to assure the success of the project from a strategic, environmental, technologic and economic direction based on COBAPACK approach.

Dissemination tools and activities could be divided in two main groups:

- Industrial level: For the SMEs, the principal objectives are to obtain results that will increase their competitiveness and market opportunities and to show these results to any potential client, in order to have a wider commercial activity and increase the company benefits. Activities such as participation in fairs, seminars, press releases are aiming these results.
- Non-commercial level: The research and technological development (RTD) participants of the project are more focussed in non-commercial promotion and scientific aspects of the work. Only non-confidential project results are susceptible of publication or dissemination in journals, web-sites, congresses, workshops, fairs and seminars.

Furthermore, there were two scientific publications related to COBAPACK project, always taking care of the protection of the intellectual property rights (IPRs), without risking the possibility of applying for a patent, as it seemed to be some partners' intention. In this way, the scientific field was also addressed in this type of events.

The dissemination actions for COBAPACK project will continue after the end of the project, mainly focused on the commercial audience, aiming the successful exploitation of the project results. Different Dissemination tools have been prepared, such as:

- maintenance of the online portal - website: http://www.aimplas.es/proyectos/cobapack/
- COBAPACK logo,
- leaflet,
- presentation of the project,
- press releases.

All these resources are available at the public part of the website and will be displayed in fairs and meetings.

Potential impact and exploitation

The new technology developed in the COBAPACK project may have a significant impact on the plastic industry; improving the current plastic food packaging alternatives and offering a new range of environmentally friendly packages. True industrial impact will require further investment, aimed to optimise the actual scale-up of the compound, co-injection and recycling processes making them suitable for a continuous fabrication stage.

Although the project development is aimed at specific food packaging (according to the end-user business field), the compound developed (under process of patent application) plus the improvements / adjustments in the co-injection technology which has given the best results, will be able to be applied to other packaging sectors, provided that the specific requirements of each food packaging application can be fulfilled.

In addition, the impact to other industry sectors such as cosmetics, chemical and pharmaceutical and co-injectors machine manufacturers could be additional business. The future owner of the compound patent will take into account these new niche market sectors.

The protection plan of the project results has been initiated. It is foreseen to apply for a patnt based on the compound developed and a trade mark of such material.
One of the SMEs will be the coordinator in a new DEMO-SME proposal to optimise and industrialise what has been developed and researched within COBAPACK, where also another SME and the End-user from the project will participate, in addition to 2 out of the 3 RTDS, as supporters in the technological transference.

Contact details: AIMPLAS (Coordinator)
Tel: +34-961-366040
Fax: +34-961-366041
proyectos@aimplas.es

List of Websites: http://www.aimplas.es/proyectos/cobapack/