Future Development Opportunities for the Melt Strength vs Melt Flow Index Project 25th March, 2013 Author: Gareth Davies – Industry Collaboration Manager – Polymers

This report sets out to summarise the findings from conversations held with the original stakeholders of the working party that have been part of the group investigating the potential for the “Melt Strength Index”. The concept requires development to help manufacturing companies truly understand the variances in performance, primarily extensional, for polymers that they either produce or convert within their businesses. This follows on from the discussions and work leading to the publishing of the Technical Report “Melt Strength as an alternative to Melt Flow Index” and webinar (including papers) presented in 2012. The project has now been running for approximately 24 months and the Materials KTN Polymer sector board have requested that this phase be concluded by highlighting options by which the project can be investigated and the applicational development of the concept be taken forward via a collaborative and if applicable publically funded route.

Consortium The stakeholders that have been involved in the discussion are as follows: Lucite International

Dr. Ian Robinson

Global Materials Science Consultant

Victrex plc

Dr. Alan Wood

Chief Scientist

NPL

Dr.Martin Rides

Research Scientist

Durham University

Prof. Tom McLeish

Pro-Vice Chancellor for Research

Dr. David Hoyle

Researcher

Dr. John Duncan

Director

Lacerta Technology

It is apparent from the initial conversations with the main stakeholders that there is indeed interest in supporting a collaborative project moving forward. However the challenge is identifying a meaningful approach for the project that would engage and in turn meet the requirements of the stakeholders. It must also be stated that no one stakeholder is able to directly fund this project however there was agreement in principle that in kind contributions / time could be made available with a clear business case having been made. With a number of different funding routes open to the consortium, the last month has been spent canvassing the stakeholders with the aim of arriving at a series of short and long term options to present to the consortium and Polymers Sector Board of the Material KTN for consideration. 1

Considering all the views and discussions to date it would seem that the consortium has several very interesting routes to investigate how the principle of a Melt Strength Index could be applied to the industrial setting. These will be detailed in the course of this report. As discussed with the group, the key to constructing a robust concept and solid working consortium would be to achieve the balance between the following stakeholder groups.

Diagram 1. Diagram to show the interrelation between the key stakeholder groups (with A being an ideal scenario to meet stakeholder requirements and to provide a project with significant impact and industry engagement.)

To date, the nature of the working group has been between our Research partners and the Suppliers of the raw materials. However to provide significant impact to the impact statements and business case for any funded development there will need to be significant engagement with converters in any consortium.

Impact Fundamentally, it is agreed that there is a need to develop an understanding of “why this is important to a converter or supplier?” and “what impact will this approach have on their processes?” This can only be done by working with converters and suppliers from all sectors and developing the understanding that the impact of the MSI approach in terms of operational improvement and business profitability. It is agreed across all the stakeholders that any development project will need to focus on the following points       

Definition of the parameters of Melt Strength Index and a common nomenclature Full industry engagement Fully developed value proportion for the proposed technology and methodology Development of cost effective and readily accessible technology solution for industry Correlation between the new methodology and Melt Flow Index Application in all, and if not the majority, of plastics converting processes Where relevant and possible, the methodology should drive forward standards of testing and quality control

In order to fully engage the multinational stakeholder of Lucite and Victrex it was agreed that some sector focus would help structure internal justification for taking an active part of the collaborative consortium rather than taking a supervisory position. This would have the benefit of providing a 2

clear focus on specific conversion processes, creating a wider engagement of the supply, and ultimately strengthen the involvement of the Large Enterprises (LEs) in any consortium built for a project. Based upon this reasoning it was agreed that Lucite would focus on Thermoforming and Victrex would support Fibre Manufacture, both process with high degrees of extensional flow. To capture the wider volume markets, it was suggested that INEOS may be a good partner for Blowmoulding or other high rate / long flow path processes. It has also been discussed that the use of a refined MSI methodology could also be of significant use to converters using variable streams of recyclates, whether that is part of the closed loop manufacture of product e.g. edge strip in thermoforming sheet extrusion with the implication of high residence times in process, through to the use of commoditized recyclate streams from various external sources. By creating work packages based on specific processing techniques, this focus will allow a modular approach to any projects or funding proposals that are pursued. For example we can take one specific process and seek to apply for a smaller grant to fund the work for that specific example or we can build a larger project that will be focussed on a number of parallel work packages / MSI solutions covering a number of different processes.

Technology Options The use of Melt Strength as a measure of extensional properties of the melt has been investigated for many years and there is a great deal of research to underpin the principles of the MSI approach; however there seems to be little or no crossover from the academic research into its use in an industrial setting. From the discussions to date and our current understanding of the state of the art, the consortium has two main concepts that could be pursued and that would provide accessible and cost-effective methods for converters which could be retrofitable / interchangeable on existing MFI equipment, providing the user with a qualitative indicator of a compound’s extensional performance. These options are:  

Flat faced die – Initially investigated by NPL Hyperbolic die – Durham University

There is another development option in the form of an adapted Dynamic Mechanical Analyser (DMA) concept which has been discussed between Lacerta and Durham University and this approach could provide industrial users with an automatable quantitative analytical methodology. Whilst these options could be considered to be competitive solutions this actually provides an element of contingency to any development project that is undertaken. That is to say that if a project was to develop the adapted DMA equipment but this should fail or not be economically viable, the work could fall back upon a retrofitable die solution thus mitigating the potentially perceived risks to a funding body. Also a specific die may not be applicable to a certain group of polymers or processes; therefore the consortium would have a number of options to explore.

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It has also been noted that for any solution that is developed it would be pertinent to develop a greater understanding of the effects of pressure, volume and temperature on the test methodology. It is reasonable to suggest that this could be investigated but only in a larger scale project or as a separate academic piece of research.

Development Options Taking into consideration the views, needs and requirement of all stakeholders, it is suggested that we create two projects proposals to be explored on different scales and timescales. These are summarised as follows:

Option 1: Short term development (Timescale: 6 to 8 months) Aim: The investigation and development of a retrofit able die approach to provide qualitative analysis of variable incoming raw materials. Focus: Converter with high use of recyclate polymers. Possible Funding Routes: METRC Funding (N8), Innovation Vouchers (NPL), SPARK Awards. Project Partners: NPL, Durham University, Industrial lead SME company and possible supplier involvement.

Option 2: Medium term development (Time Scale: 18 to 36 months) Aim: Development of new and standardised MSI test methodology for UK plastics sectors. Focus: Multiple converters using polymers requiring high degrees of extensional performance / melt strength. Possible Funding Routes: TSB Collaborative Research & Development Funding, TSB Launchpad Funding. Project Partners: All Stakeholders plus new suppliers and focussed consortium of UK SME converters for each plastic process selected. To truly understanding the benefits of any MSI methodology we will have to undertake an element of benchmarking of the current understanding and performance of polymers and the Melt Flow Index in the current setting for each of our projects. This would also serve to create a greater degree of buy-in to the methodology by working with converters to gain greater understanding of the material variations they may currently experience and how these variations can affect their processes and ultimately their profitability. The next section explains in greater detail the proposed approach to each of the project options.

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Option 1: Short term development (Timescale: 6 to 8 months) Aim: The investigation and development of a retrofitable (MSI) die approach to provide qualitative analysis of variable incoming raw materials for converters focussed on the use of high volumes of recyclates from multiple sources. Impact: To allow greater surety of raw material supply and helping to converters to further progress a UK circular economy by enabling companies to confidently use higher levels of recyclate in higher specification applications. Possible Funding Routes: METRC Funding (N8), Innovation Vouchers (NPL), SPARK Awards. Project Partners: NPL, Durham University, Industrial lead SME company and possible supplier involvement.

Diagram 2. Stage diagram to show the suggested key elements to a single sector focus project.

Stage One: Research partners will help SME company to benchmark their incoming raw materials streams and correlate MFI versus laboratory based rheological measurement of Melt Strength thus allow the converter to profile preferred operational values for both measurements. This data can be used to help model either a flat faced / hyperbolic die solution that best correlates to laboratory results. Stage Two: Using the outputs of the modelling phase, a prototype die can be manufactured and tested in the laboratory to measure the performance of the actual die. The methodology for using the die is developed as a result of the findings. Stage Three: The prototype die is sent to the converter and in-field testing commences with data being fed back to the research partners in order to calculate and validate a scale for MSI. This can then be used by the SME converter to test incoming material batches versus the proven best parameters for resultant MSI readings. Actions to date: Due to the variations of requirement of each of the smaller finding routes it may not be possible to include both research partners; however if it is clearly understood from the outset that all data will be shared with the original consortia this may open the opportunity to use this initial route. Both research parties have been contacted to discuss. Investigation in to other sources of funds is ongoing with a host of different call dates available.

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Option 2: Medium term development (Time Scale: 18 to 36 months) Aim: Development of new, quantitve and standardised MSI test methodology for UK plastics converters using polymers requiring high degrees of extensional performance / melt strength. Impact: To provide the UK plastics sector greater control and flexibility in sourcing their raw materials by providing an indication of Melt Strength rather than just Melt Index which does not always indicate suitability to their process or product requirements. Enabling the UK plastic sector to gain the improved understanding of the extensional characteristic of polymers from batch to batch that will in turn allow converters to: •

Save time, energy and labour wasted in production due to “out of specification” grades

•

Save time and effort spent validating new and alternative grades of prime material

•

Increase the range of raw materials they can source for specific cost sensitive applications

•

Increase the ability to effectively control the use of highly recycled polymers in products and processes

•

Increase the confidence when seeking to attain ever increasing recyclate content targets

•

Increase the understanding of the effect of Melt Strength on design, materials section and light weighting

•

Increase the UK polymers sector competiveness and further increase world-leading position for quality and engineering

•

Allow greater amounts of recyclate in products due to the increase understanding of different and varying materials streams

For any large scale funding a clearer picture of the wider impact would need to be developed i.e. size of markets, labour, energy and time lost due to out of specification materials, etc. This could be developed in conjunction with the stakeholders but may require some input from market data sources or a partner such as the British Plastics Federation (BPF) who has the holistic regional view.

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Diagram 3. Stage diagram to show the suggested key elements to a multi-sector focus project.

Stage One: Research partners will help each SME company in the Sector Focus groups to benchmark their incoming raw materials streams and correlate MFI versus laboratory based rheological measurement of Melt Strength allowing the profiling of preferred values for both measurements. This data can then be used to help model either a flat faced / hyperbolic die solution as well as providing a data set to help create design and configure assumptions for the adapted DMA concept. Stage Two: Using the outputs of the modelling phase, a prototype die can be manufactured and tested in the laboratory to measure the performance of the actual die. The methodology for using the die is developed as a result of the findings. The effects of change in pressure, volume and temperature could also be investigated at this point. Using the output data from across all sectors the adapted DMA method approach can be defined. Work on creating a new standard or amendment to the existing standard ISO 1133 ASTM D1238 could start based upon the results gained in the initial stages. Stage Three: The prototype die is sent to the SME converters and in-field testing commences with data being fed back to the research partners in order to calculate and validate a scale for MSI dependant on process or materials being used. This can then be used by the SME converter to test incoming material batches versus the proven best parameters for resultant MSI readings. A prototype of the adapted DMA will be produced and a testing phase commenced against batches of materials highlighted in the die development phase. Stage Four: Large scale funding would need a clear exploitation plan in the initial stages and this can be discussed with the original stakeholders and outlined at the start of the project. Taking the issue that any large scale project needs the “buy in “of industry, we have constructed a proposed project structure similar to that seen in the European Framework Programme 7 under Research for the benefits of SME Associations. This facilitates industry-wide collaboration in the project, creates a greater data set to be derived from the testing and wider pathways for dissemination of the results further helping commercialisation of any concepts to be launched. 7

The Technology Strategy Board has issued a call for “Materials innovation for a sustainable economy” with a deadline for registration of the 17th April, 2013. This concept could be applicable in terms of enabling the wider plastic community to contribute more effectively to a circular / sustainable economy. This will need verifying with the TSB. If agreed, the following consortium structure would be used to recruit the required SME partners.

Diagram 4. Draft consortium structure required to facilitate a multi-sector focus project.

Actions to date: This project approach has been formulated to create the opportunity for as wide ranging industry collaboration as possible to ensure that any standards and methodologies developed during the project have been formulated in conjunction with industry. The project would require an experienced Project Manager and the BPF may be a suitable option due to their extensive experience in running collaborative EU based projects. Contact will be made with the TSB to get feedback on the relevance to call, overall appeal of the project and its approach. 8

Summary Whilst considering the future opportunities for the Melt Strength project, we can summarise that:         

We have an enthusiastic and engaged consortium of stakeholders. The concept is strong but requires some consideration of the current state of the art and competitive landscape. We have limited opportunities outside of funded project routes to take this concept forward. We require industrial partners to gain credibility, a suitable mass of relevant data and ultimately the buy-in and adoption of the concept of the MS approach. Both project approaches build around the same set of core drivers and it is conceivable that they could be run individually or in parallel and if not merged. We have a model to engage our Large Enterprise partners whilst providing structured focus for a subsequent project. All funding routes considered to date will be competitive. Approaches to TSB and BPF are instrumental in building a successful project proposal. Further assistance will be required to enable the consortium to move forward with a grantfunded application.

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