Tag Archives: rubber

Careers Section. Addition to our web page

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Hi Everyone           Another blog from Norman – November 2019.

Just to bring to your attention that we have added another section to our web page.

At the far right end (nothing political intended) of the menu bar you will now see the new section. It is labelled “Careers”.  Click on it and you will find a copy of the job advert we have just placed on “INDEED”.

This is a new idea to us and we hope, at a later date, to add some comments/ideas from existing staff – could be interesting. Of course we will be completely unbiased and only publish the good ones.

Please keep an eye on this new part of our site (as well as all the rest) as it might change quite quickly.

Cheers for now.

Norman

How to ‘Cure’ Some Moulding Issues

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Rubber is of very little use until it has gone through the process of vulcanisation, where heat gives the energy needed for the long isoprene polymers to cross link, usually with sulphur side chains. Vulcanisation, often referred to in the rubber trade as ‘Curing’, turns rubber into the solid, elastic material that makes it so suited for the thousands of applications it is used for. As cured rubber is much stiffer than its pre-cured form, it has to be cured into the final form it is required to take, be it an O-ring, tubing or a coating on a fabric. Therefore, most rubber products are cured in the mould, which can be a classic mould press (with 2 heated plates pressing down on an amount of rubber to form the item with a small amount of flash) or injection moulding (where the mould is static and heated and the material is injected into it at pressure.

I’d like to take you through a couple of examples of experimentation made by our rubber consultant Norman Challinor that show how curing in the mould might not be as simple as you’d think.

Above is a photo of a test moulding using a piece of steel pipe as a mould (rubber piece is cylindrical around the rear) and 2 hot plates to cure from the top and bottom (as shown here). In this test a piece of wood was placed between the top hot plate and the rubber sample (as shown in picture) while the bottom hot plate was allowed to make full contact with the piece. After a set amount of time the hot plates were disengaged and the piece allowed to cool.

What can be seen is that the thermal insulation provided by the piece of wood prevented the top half of the sample from curing, which can be seen in the noticeable deformations made using a pen (while the cured lower half sprang back in place. The Steel pipe allowed the heat to conduct though the exterior (behind the sample in this image) but the wood retarded curing from the top of the piece due to restricting heat transfer. This shows the importance of the correct cure time for the thickness of a moulded object and for a manufacturer to think about where the heat sources are in their mould to ensure a complete cure of the product.

This second image shows an experiment to test a belief held by many in the rubber industry about Transfer Moulding.

Transfer moulding is like injection moulding, in that the rubber is ‘injected’ under the pressure of a hydraulic cylinder, but it is injected through several holes in the top plate of a heated mould (once the mould is closed) until the mould is filled.

It was believed that through the process of injection, the rubber compound would mix and form a homogenous piece of rubber. To test this, three separate sheets of rubber were placed in the hydraulic cylinder; in this case blue first, then white and finally red. As you can see, contrary to common belief, the rubber sheets failed to fully blend in the mould, leading to the patterning seen above. These separate layers may become weak points in the finished product, even though the product has cured evenly. It suggests extra care is needed at the moulding blank preparation stage, such as preheating to ensure an even heat throughout the rubber (which is known as the blank) before injection.

These two fun examples are great ways to show how it is important to test rubber technology theory to ensure success on the factory floor, even if what you are testing would seem like common sense. Such as the use of 2/3mm thick laboratory test pieces will not necessarily translate the correct cure times for the full sized product, due to the poor heat transfer of rubber itself.

Many thanks to Norman Challinor for the 2 sample pieces, and the stories and lessons behind them.

If you are having moulding issues, or think one of our products could help give you a more even, cheaper cured product please get in touch via our website www.allcocks.co.uk, phone 0161 223 7181 or visit our stand at DKT2015/IRC 2015 12-352 Nuremburg 29th June to 2nd July!

Matt Darlington

Review of the Year – 2014 @ J Allcock and Sons

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2014 at J Allcock and Sons Ltd.

It’s been another great year here at J Allcock and Sons. Rubber crumb and granule sales are up on last year, with an additional granulator to be installed next year and upgrading the line at our Wellington Rubber branch. FKM crumb production has increased 20% from last year and looks set to continue to increase into the New Year. In addition to our stringent particle size laboratory testing, we have recently instigated a quick pass/fail test during production, at short regular intervals. This will maintain the quality of our material that we’re known for.

Silicone sales are also up from last year, especially our Food Grade Silicone Emulsions. Of the small number of complaints to the company, most of them were due to poor housekeeping by the end user leading to silicone splitting (for tips on how to stop this, have a look at our previous blog post ‘A Splitting Headache’).

With this sustained increase in sales, we’re also looking into expanding our storage facilities, expanding our storage capacity by tens of tonnes.

Finally, we’ve welcomed 2 new members to the company. I joined just before Luke departed for a year in Australia, and Stephen has joined to learn the ropes controlling stock and purchases.

Looking to the New Year, we expect to continue our personalised service for our clients and welcome new clients from both the UK and the continent, thanks to our upcoming foreign language translations of our website. We’ll also be at DKT (Deutsche Kautschuk-Tagung) 2015 in Nuremburg in the summer to show our crumb and rubber reclaim to the European Rubber Community.

We’d like to say a big thank you to all our clients for continuing to choose us as there supplier, and the staff at J Allcock and Sons for a great year. We wish you all a merry Christmas and a happy 2015!

Matt Darlington

Allcocks at the IRC Rubber Convention 2014 – Manchester

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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.

Rubber Reclaim Part 2

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Although we’ve blogged about Rubber Reclaim in two previous posts (31/08/12 & 13/09/12), we thought another blog would reinforce Rubber Reclaim as a viable rubber hydrocarbon source, carbon black source and process aid.

In the 31/08/12 blog, which is still available to read, we wrote about how it is made, its basic properties and why a compounder should use it. In this post we hope to expand on these slightly and talk about ourselves, as UK and European suppliers of Reclaim.

How Rubber Reclaim is made:

Step 1) Collection and Selection of suitable materials

This is probably the most important step. In order to get a uniform and consistent product you have to use the correct materials. This is a part of the process that for many years has been overlooked hence producing inconsistent materials.

Step 2) Reduction in size and removal of contaminants.

In Tyre Reclaim this consists of removing the bead wire, cutting out the side wall then granulating the remaining materials to 2-4mm removing textile and metals.

In Butyl Reclaim Tubes are de-valved  and patches removed before being granulated.

Step 3) Blending

The rubbers are mixed with the chemicals required and the oils needed for the reclaiming process to take place.

All the chemicals and oils used today are REACH registered and compliant on PAH’s

Step 4) Cooking

This is where the materials are heated up. There are 2 main ways this is done either using an extruder to produce mechanical heat. Alternatively the materials are cooked in a digester using steam pressure to give 160° C

Step 5 ) Mastication

Either in the extruder or on a 2 roll mill the rubber is worked which breaks the polymer chain, also refining and blending the reclaim

Step 6) Filtering

The better quality producers at this point extrude the materials through a 60’s mesh (250 µm) filter to remove any undigested materials (nibs)

Step 7) Finishing

The filtered material is either extruded into blocks or is put back on a mill where a paper thin sheet is built up to 15mm thickness before being cut into blocks, coated in anti-tack agent and weighed off into the desired bundle weight (normally 25 kilos, but any bundle size is possible on request)

So why should you use Rubber Reclaim?

3 Reasons; RHC Source, Carbon Black Source and Processing Aid.

1) Rubber Hydrocarbon Source

Reclaim is a more cost effective source of rubber hydrocarbon than virgin rubber.

  • Attractive Price – Reclaim generally contains 50%+ RHC . For every 1% Reclaim you add you save 0.6% on Compound Cost*
  • Price Stability – Prices are not affected by NR and SBR prices.

* Based on an average compound cost of £1-70/kg

NR Prices versus Reclaim Prices

NR Prices versus Reclaim Prices

2) Carbon Black Source

  • Tyre reclaim contains approximately 27% of reinforcing Carbon Black
  • Easy to use as a Black Masterbatch
  • Much cleaner and easier to handle

3) Processing Aid

  • Improved Processing
  • Uniformity
  • Low Heat Development
  • Low Thermoplasticity
  • Minimum Reversion
  • Low Swelling and Shrinkage
  • High Rate of Cure
  • Good Aging
  • Good Shape Retention
  • Improved Tack

Other Savings include reduced mixing times and power consumption

Markets

There are 3 main types of rubber reclaim; tyre, butyl and EPDM. These reclaim serve a number of markets:

1) Tyre Reclaim

  •  Tyres- New
  • Retreading
  • General Moulding
  • Belting
  • Adhesives
  • Footwear
  • Sheeting/Matting

2) Butyl Reclaim

  • Inner Tubes
  • Tyre Lining
  • Tyre Repair
  • Cable Bedding Compound
  • Sound Reduction
  • Sheeting & Belting
  • Mastics and Adhesives

3) EPDM Reclaim

  • Automotive Extrusions
  • Hoses
  • Civil Engineering Extrusions
  • General Moulding
  • Roofing Membrane

Where do J. Allcock & Sons fit in?

J. Allcock & Sons are UK distributors of  Rubber Reclaim for GRP Limited, who are based in India and have a maximum capacity of 89,000MT’s per year.

We have been supplying reclaim from GRP Limited for many years and have proven it to be a successful partnership and have expanded our customer base overseas.

Although GRP Limited have distributors all over the world, any enquiries are welcome and if we cannot supply GRP Products to your location ourselves, we would happily point you in the right direction!

 

To conclude this post. Please do not hesitate in emailing ja@allcocks.co.uk  or phoning on +44 (0)161 223 7181 for any enquiries or information on reclaim. We firmly believe reclaim has a place in todays rubber compounding market.

 

New Year 2014

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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.

Red/Brown & Green FKM Crumb Available

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Red/Brown and Green FKM Crumb

Red/Brown and Green FKM Crumb

J. Allcock & Sons’ now have the ability to provide an extra 11 tonnes of Red/Brown FKM Crumb and 4 tonnes of Green FKM crumb per month.

Cured FKM scrap is sent to our facilities on a monthly basis and we granulate and “crumb” this FKM scrap to  72′s and 120′s mesh particle size. These particle sizes are not averages, so when we say 120′s Green FKM Crumb, we mean the biggest particle you will find will be 120′s mesh!

We always ask the customers we visit: What’s the cost of testing FKM Crumb in your compound? Compare that amount, to the amount you will be saving if tests came back positive and you started using it…

If you are interested in trialling some of the above crumb, please contact us at ja@allcocks.co.uk or +44 (0) 1612237181.

Alternatively, if you are unsure about using a different FKM compounded crumb in your own FKM compound, why not speak to us about “crumbing” some of your scrap and J. Allcock & Sons’ sending it back to you?

Carnauba Wax

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I haven’t written a technical blog recently, so I have decided that I should write one regarding Carnauba wax. We have high stocks of Type 3 Carnauba wax, in powder form, so perhaps it might bring us some new sales!

With the help of Norman Challinor, here is some information on Carnauba wax!

Carnuaba wax is also known as Brazil wax and Palm wax. It is a hard wax obtained from the leaves of the palm copernicia prunifera - a plant native to and only grown in north eastern Brazil.

It is usually in the form of hard yellow / brown flakes that can also be ground down to a fine powder and often offered in that alternative form.

Due to its fantastic properties compared to other waxes, most people believe it is one of the best waxes in the world; hence it is sometimes referred to as the “queen of waxes.”

It has a melting point of 80 – 86 oc and a density of about 0.97

The main components are:-

Aliphatic esters                                                   (40% by wt.)
Di-esters of 4 – hydroxycinnamic acid                (21% by wt.)
ω – hydroxycarboxylic acids                               (13% by wt.)
Fatty acid alcohols                                              (12% by wt.)

Predominantly derived from acids and alcohols in the c26 – c30  range.

Carnauba wax, can come in Type 1, Type 3 and Type 4. These “types” relate to the purifity level, with Type 1 being most pure and Type 4 being least.

It has a very wide range of uses, including …..

  • Polishes (Usually Type 4 used)
  • Food (chewing gum, gravy, sauces, sweets etc) (Usually Type 1 used)
  • Pharmaceutical (tablet coating agent)  (Usually Type 1 used)
  • Cosmetic (Usually Type 1 used)
  • And of course, as a process aid and mill / mould release agent in rubber compounds, particularly the harder to process specialist materials. (Usually Type 3 used)

For rubber compounders:

In rubbers, the hard nature of the material will not act as a softener but will behave as an internal lubricant, facilitating the incorporation and dispersion of the non-rubber ingredients.

Its relatively low melting point means that it will migrate to the surface of the rubber and form an extra, very thin, layer between the rubber surface and the metal it is in contact with – - i.e. The mill bowls or the mould surface.  The hardness of the wax means that it will not act as a sticky softener, but will form a release layer, overcoming the tendency for the rubber to stick to the metal.

Allcocks mostly sell, Type 3 Powder, and we really focus on selling to the high specification rubber compounding industry, such as FKM compounds.

Here is some technical information on our T3 Carnauba Wax Powder:

Solubility                                      Insoluble in water; partially soluble in Alcohol.
.                                                   Soluble on warming in Ethyl Acetate & Xylene.
Melting Point                               80-86°C
Acid Value                                   2-7 mg KOH/g
Sponification Value                     78-95 mg KOH/g
Ester Value                                 71-93 mg KOH/g
Sulphated ash                             No more than 0.25% w/w
Unsaponifiable matter                 50-55 μm
Particle Size                                100%  passing 600 μm
.                                                   94.8% passing 300 μm
.                                                   88.1% passing 250 μm
.                                                   40.6% passing 125 μm

If you have any questions regarding carnauba wax, please feel free to email ja@allcocks.co.uk! Despite only selling T3 Carnauba Wax powder, please feel free to get in touch regarding other types, we may be able to help.

ISO 9001:2008

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J. Allcock & Sons have been certified ISO 9001:2008 since 14th of January 1997. This month we had our re certification audit and have now gained certification up until 9th March 2016.

We are proud to be certified ISO 9001:2008 and believe this shows our commitment to keeping high standards and customer satisfaction throughout our organisation. We also believe we are probably the only rubber recycler in the UK to attain this certification.

ISO 9001:2008 Certificate

 

 

Butyl Reclaim (GRP BRI 75R) Now Stocked

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J. Allcock & Son’s will now be STOCKING GRP BRI 75R Butyl Reclaim (Formerly BT.999.)

We have decided to take this important step forward in butyl reclaim supply, as there has been a huge increase in demand over the past year and we expect this to continue throughout 2013.

J. Allcock & Son’s, where possible will always try to be your most flexible supplier. We understand the need to deliver a high quality service. After all, what is the point of using a high quality product, if you do not know that you are going to receive it when you need it?

  • GRP BRI 75R is manufactured by Gujarat Reclaim & Rubber Products Ltd., India.
  • GRP BRI 75R is a reclaimed rubber made from Butyl inner tubes, together with reclaiming aids.
  • GRP BRI 75R is PBN free and PAH conformant.

Product Description

  • Colour: Black
  • Form:   “Blanket”

Composition

  • Carbon Black:            32 ± 4%
  • RHC (by difference):  50% min
  • Ash Content:              4 ± 2%
  • Acetone Extract:        9 ± 3%

Properties

  • Specific gravity:                                1.14 ± 0.02
  • Mooney Viscosity at 100°C:             30-45 ML 1+4
  • Hardness Shore A:                           51 ± 3
  • Tensile Strength:                              75 kg cm^-3 min
  • Elongation @ Break:                        480 % min
  • State of refining:                               Superfine

Data sheets for GRP BRI 75R can be found online, in our data sheet library or on the butyl reclaim product page.

J. Allcock & Sons Ltd. also stock GRP NRM 35R (formerly GR.444 Tyre Reclaim) and GRP NRC 25R (formerly RT-SLAB Tyre Reclaim)

J. Allcock & Sons Ltd. are the official UK distributors for Gujarat Reclaim & Rubber Products Ltd.

For any further technical questions on GRP BRI 75R, please feel free to phone or email, and ask for Norman or Luke.