Allcocks at the IRC Rubber Convention 2014 – Manchester

As we blogged at the time, we attended and manned a stand at the IOM3’s Rubber Convention this year in Manchester. We enjoyed meeting many people from the rubber industry as well as those researching the next big developments for rubber.

Andy Rushton and our stand at the IRC Rubber Convention 2014

Over the two days of the convention (14th and 15th May) we gave out two copies of a history of Manchester in photographs. The first was won by Ms Karin Janet Stein Brito (see picture below) of the Polymer Technology Centre – SENAI in Brazil, whilst the second was won by Mr Bill Adam of Adam Polymer in the UK.

We look forward to the next conference and hope to spread the word of Rubber Reclaim and Rubber Crumb such as their benefits in formulation and myriad uses.

New Year 2014

Hi Everybody,

Just a line to say Happy New Year to all our readers, suppliers and customers.

Best Wishes from all the staff.

Please note our staffing changes:-

Arthur Brookes has now left our employ, and we all wish him the best in his well earned retirement.

Keith Devine has now fully taken over Arthur’s duties, and you should now contact him for all your crumb, granule and recycling requirements.

Sadly, Luke Gilbert will be leaving us at the end of January. He is going travelling in Australia, New Zealand and South East Asia. It’s alright for some !! He will be sorely missed.  A replacement will be put in place as soon as possible.

Differences between Size Reduction, Reclaiming and Devulcanisation, in the recycling of rubber.

Differences between Size Reduction, Reclaiming and Devulcanisation in the recycling of rubber.

We have consistently found that the rubber industry confuses itself when discussing recycled rubber. Information has started to become lost and miss-translated; people have stopped collaborating and sharing their knowledge. The purpose of this blog post is to hopefully clear up the difference between the three types; size reduction, reclaiming and devulcanisation. I have already written about both size reduction and reclaiming processes and their advantages, but feel a post about the differences between all three at once,  is worth my time.

First of all, let’s quickly discuss each process:

Size Reduction

Recycled rubber has now become the term most associated with size reduction recycling. This is due to the fact that there has been no chemical process involved in the recycling process. It has been, exactly as named, “Reduced in size”.

There are 3 main types of size reduction recycling; Ambient Grinding, Cryogenic and Wet Paste.

  1. Ambient grinding is grinding/tearing the rubber to the small sizes at room temperature. This is our preferred recycling technique as we firmly believe it gives not only the most economical sized reduced rubber but also the most reusable (due to its shape giving the largest surface area).
  2. Cryogenic is the freezing of scrap rubber using liquid Nitrogen and reducing the size literally by smashing it to pieces. This is less economical due to the amount of liquid nitrogen used per kilo of scrap rubber (1:1 Ratio). The final shape also gives a much smaller surface area as it has flat surfaces, this means less rubber can lock/bond into the rubber compound.
  3. Wet Paste is another grinding technique. This is where the rubber is ground while in water. This can produce finer particles than ambient grinding due to the rubber being in cooled down by the water. Unfortunately this technique is not very economical because the ground rubber almost has an affinity to the water and drying the recycled rubber is extremely hard and costly.

Rubber Reclaim

This is where people start to get confused. Reclaim, Rubber Reclaim, Reclaimed Rubber, as stated is a much more complicated form of recycled rubber, it has been put under a chemical process. In fact, it has been put under a complex thermochemical and mechanical process.

Rubber is first reduced in size and then mixed with oils/reclaiming agents and heat. Without getting into too much detail, this process shortens the polymer chain.

Notes:

  • During the reclaim process small amounts of sulphur cross links may be broken – but not enough to claim it as devulcanisation.
  • For rubbers, such as Nitrile (NBR) which has high chemical and heat resistance, reclaim is not yet possible.

Devulcanisation

Devulcanisation is the rarest of rubber recycling, but probably has the biggest potential. It is the breaking of the sulphur cross links. Breaking these sulphur cross links means that the resulting recycled rubber is almost exactly like the starting rubber compound. The recycled rubber will contain up to 90% of the original properties. This would make it the easiest recycled rubber to reuse.

Unfortunately breaking the sulphur cross links is extremely difficult and not many devulcanisation techniques are available due to economical issues at present. Although Remould.org.uk are getting close.

Differences between Size Reduction, Reclaiming and Devulcanisation:

From the explanations above, the differences are clear.

Chemical Structures:

  • Size reduction has no effect on the chemical structure of the rubber.
  • Reclaiming rubber breaks bonds within the polymer chain (and a small amount of sulphur cross-links) and therefore has an effect on the polymer chain length.
  • Devulcanisation has a small amount of effect on polymer chain length but mostly gives large polymer chains which have no sulphur cross links.

Uses:

  • Size reduction is an additive/cheapener rather than a material for replacing rubber polymer in the rubber compound. The ratio of the original materials in the rubber compound would be the same. Larger, size reduced, rubber (rubber granules) can be used in horse arenas and playground surfaces.
  • Reclaim, unlike size reduction can be used to replace some rubber polymer being added in the rubber compound. In fact, if you really wanted, reclaim could make rubber compound by adding curatives/accelerators, although the quality would be poor.
  • Devulcanisation, similar to reclaim would be able to replace the rubber polymer. In fact, it would probably be able to replace nearly the entire rubber polymer and most of the compound!

Visual:

  • Size reduction of rubber produces, shred (for tyres only), granules and crumb.
  • Reclaim is extruded into blankets on a mill.
  • The best devulcanised rubber would be extruded and would be available like reclaim.

 

I hope this post will shed some light on the confusion between the two different types. If you have any questions feel free to leave a comment and I will get back to you ASAP.