Covid Capers

Hi Everyone

Sorry about the title. Wasn’t trying to be funny or demeaning, but couldn’t think of a better title. It’s the most serious thing most people will be able to remember, or cope with.

What will it be like afterwards?  We probably don’t want to think about that yet – - let’s get through it first.

If anyone is interested at the moment I am still around but working from home. If anyone else is in the same boat …………… difficult to keep the concentration going isn’t it. If you want to get in touch my e-mail is or if you ring the office they will be happy to give you my mobile number. Allcocks are still open and the offices are manned as normal – ish

Let’s hope it passes safely for as many of everyone as it can.

Keep smiling



Hi Everyone

We have a special blog today …………………………

One of our staff members, Sally, has been with the company for 40 years as of today.

We all want to thank her for the help she has given to everyone and the dedication to her duties she has shown over this period.

Wonderful,  All our Best Wishes and thanks !

Careers Section. Addition to our web page

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.


Customer Testimonials.

From Norman C. to all our friends out there.

It’s always good to blow your own trumpet now and again. It makes you feel good.

Well at least it me feel good. We have received some testimonials from customers and we thought it would be a good idea to share them. We always say that we are good at what we do, but it’s nice when other people say so.

a)         Having worked with Wellington Rubber for many years we have found their “Shred” to be a consistent, high quality product that is well presented. As a supplier they have always responded quickly, their “on time” delivery is good and the overall level of service is excellent.

b)          From John B.

It has been our great pleasure to have been able to conduct business with J. Allcock & Sons Ltd and Wellington Rubber Company Ltd for over 10 years. In that time, we have always found them to be a most reliable supplier, always willing to oblige where ever possible.

The information given is as expected from a quality supplier, attentive and willing to help, providing feedback and plausible reasons when the odd problem arises.     A successful partnership in business is highly reliant on the people within the organisation, it needs to meet each other’s expectations, the management team at Allcocks and Wellington Rubber excel in this field and therefore I would have no hesitation whatsoever in recommending their services and products.

c)          Tiflex Limited has a long association with J. Allcock & Sons. We have formed a great partnership with the Allcock team providing bespoke regrind materials to Tiflex specifications.

Orders are processed on time and to our delivery requirements and the prices remain competitive.     Business is conducted on a professional basis, delivered in a friendly manner and we anticipate many more years of a successful business partnership.

Well, there we are. I will pass more on as they come around.

Cheers everybody.

Mr. David Birkett. R.I.P.

It is with great sadness that we report the passing of David. He left this life last week whilst on a cruise.

Our deepest sympathy is with his remaining family.

David’s father, Laurie, started Wellington Rubber Co back in 1936, but it was in 1999 that David, by then contemplating his own retirement, sold the company to J. Allcock & Sons Ltd. It was re-located from Leeds to the JA site in Manchester in 2002, where it was integrated into the operation. David came down to JA one day a week over the first year, to make sure the changeover was effortless. We felt that it was imperative to continue with the original name as many customers were loyal to it, and it continued the lineage.

In mid 2015 WRC was moved to a new, dedicated site just a short distance away.

We are sure that David would be proud to know that his father’s company name and logo survives and is still in daily use.

ISO 9001:2015 QMS certification.

Hi Readers,

Nearly Easter …… hope you have a good break.  Easter always signals that winter is over and better weather (hopefully) is on the way.

I have some great news to pass on.  Our QMS (quality management system) certification was due for renewal, so we took the bull by the horns and went for the new, latest version viz: ISO 9001: 2015.  It took quite a lot of work, by all concerned, because the “thinking” now has a different emphasis, but we did it.  We are now fully certificated to ISO 9001:2015, as from early this month.

Copies of our new certificate, either “hard” or digital, are now available to our customers.

As Matt has now moved on to pastures new (Good Luck Matt), I will be one of the contact points.  Please feel free to contact me.

Cheers for now



Silicone Emulsions – A Splitting Headache

Silicone Emulsions – A Splitting Headache

Although it was mentioned in our most recent Silicones blog (06/03/14). We here at J Allcock & Sons thought it would be a good idea to add a post about the problem of Silicone emulsions splitting.

Silicone Emulsions are basically Silicone oil, water and an emulsifier. The Silicone oil does the job (usually lubrication), the water carries the oil and allows for easy dilution of the oil and the emulsifier binds the two together.

However, problems can arise in emulsions, the large array of splitting possiblilties are shown perfectly in the diagram below:

Taken from:

Though there are many technical terms, the origin of all these kinds of splitting are the same. Like milk, Silicone emulsions can ‘go off’ if left in a hot, moist environment. Like milk, Bacteria and fungi can grow that feed on the emulsifier and cause the separation of an emulsion, leading to a ‘lumpy’ consistency.


There are a few precautionary measures that can be taken to ensure your Silicone Emulsion doesn’t split;

  • Store the container in a cool, dry area
  • Do not store diluted material for long periods of time
  • Regularly wash out dilution vessels to stop bacteria/fungi carrying over into fresh batches
  • Use Allcosil Stabiliser to increase the lifespan of your Silicone Emulsion

We hope this helps answer any questions on silicone splitting you may have. If you’d like more info please get in contact via the website or by calling myself on 0161 223 7181.

Matt Darlington

The Cake Analogy – Fillers


When it comes to the rubber industry, there is one metaphor that seems to explain all the necessities and intricacies of rubber. “Making rubber is a lot like making a cake”. Since starting at J Allcock & Sons, I’ve heard it over a dozen times, and it still surprises me how apt a saying it is!

I’ve tried punching holes in the saying, and thought I’d finally done it when it came to this subject. If virgin rubber is the flour, release agents the butter on the tin and accelerators the yeast, what would fillers be in the cake analogy?

Calcium Carbonates – CaCO

Calcium Carbonate is a classic filler for the rubber industry. A cheap and fine grade filler suitable for almost all rubber compounds. If you want to reduce the cost per kilo of a rubber compound (and have already tried reclaim/rubber crumb, we hope!) CaCO3 can stiffen up a compound as well as significantly decrease the total cost of a compound, but it will decrease the compound’s physical properties (another point Reclaim and Crumb can beat CaCO3 on)

J Allcock & Sons provide 2 main types of Carbonate, Trucarb and V/40S Whiting. Trucarb is affectionately known as ‘Ground-up Derbyshire’ as it is simply naturally occurring limestone ground into a fine powder. If you are looking for a cheap filler, Trucarb is the way to go. V/40S Whiting is exactly the same chemically as Trucarb, but acquired from evaporating river water in Italy, and is therefore purer. This produces extremely fine powder of bright white, which is perfect for decreasing the weighted cost of a white compound, without dulling the brightness.

Here is the first hurdle for the cake analogy. Calcium Carbonate is, ironically, a lot like Sodium Bicarbonate in cakes, reducing the total amount of flour needed to produce the same amount of cake batter.

Taken From:


Barytes is a powder of Barium Sulphate, and is at least twice as dense as CaCO3. Barytes is extremely good at adding weight to your compound, such as a use in moulding rubber weights. Barytes is also very resistant to acid corrosion, as well as x-rays, infrared and radar. It can provide a ‘deadening’ quality to the rubber compound too.

We provide a single grade of Barytes, Barytes Supreme, which may not provide stealth-grade material, but will bring weight and deadening to a rubber compound.

Barytes could be considered as the fruit and raisins of a cake, any rubber compound made with Barytes will come out like a fruit cake; hard, heavy and resistant to almost anything.


Taken from:

‘Talc’/Magsil – Magnesium Silicate

Talc is another speciality filler for the rubber industry (as well as plastics, paints and paper). Thanks to it’s microscopic disc shape, Talc is able to add slip to a compound (see below for an excellent diagram). Very little talc is needed to help a compound through extrusion and calendaring, as well as adding some mild reinforcement to your compound. Talc has an extremely ‘active’ surface, again due to the flat disc shape of the particles, and thus can absorb sulphur and slow a compound’s cure rate. This can be rectified with the use of glycol.

Taken From:

Talc is also often used externally on a compound as a dusting agent (or anti-tack agent) , allowing the stacking of uncured compound sheets without the risk of them sticking together (exactly like the cosmetic use for Talcum powder).

Talc can also be partnered with Silanes, a molecule designed to chemically bond fillers with compounds such as rubbers and plastics, allowing a much larger amount of filler to be used without the degradation of properties normally associated with the use of fillers en-masse. (this will be expanded upon in the next blog post)

Two grades of Talc are available from J Allcock & Sons; Magsil Topaz 350 (or T350) which is our standard Talc, or Magsil Diamond which is a finer powder and thus is able to add greater slippage.

With its brilliant white colour, this fine powder has to be the icing on the cake, literally. Though icing sugar may not add slip to the top of a cake, it is a final addition that completes the baking of a cake in much the same way as powdering with talc signifies the completion of a rubber compound’s mix.

Thanks to Norman for helping with the technical details and editing. As always, if you have any questions please don’t hesitate to contact me by e-mail at or by telephone on +44 (0)161 223 7181

Silicone Oils, Emulsions & Antifoams

Silicone Oils, Emulsions & Antifoams

J Allcock & Sons have been selling silicones to a wide range of industries since the 1970’s. Our last silicones post on 07/11/12 missed out one of our main silicone products and as I have recently started here, I thought it would be a good first topic to write on, with the help of our technical wiz, Norman.

We’d like to go over our 3 main products in the silicone range; Silicone Oils, Silicone Emulsions and Silicone Antifoams. We’ll outline some basic information, uses and grades that J Allcock & Sons offer.

Silicone Oils

Basic Info

Silicone oils are the sensible place to start as all our silicone products are based around silicone oil. silicone oil has many names; some call it Silicone Fluid, Americans tend to call it Dimethicone, while we call it Allcosil 200.

The Scientific name is Polydimethylsiloxane, which is also the most descriptive as the chemistry minded among you can see ‘Poly’ for many, ‘Dimethyl’ for two methyl groups (CH3) and ‘Siloxane’ for Silicone and Oxygen. The resulting structure resembling this:

Taken from:


Thanks to its methyl groups and Si-O backbone, silicone oil is one of the most inert oils around. It’s a water repellent, dielectric, temperature resistant, semi-Newtonian and non-toxic lubricant, which lends itself to uses in the moulding, food packaging, automotive and cosmetics industries.

Our Range

Silicone oils come in a wide array of viscosities, which are dependent on the length of the polymer (the longer the polymer, the more viscose the oil). The different viscosities enable silicone oil to perfectly meet desired needs; Allcosil 200/20 has been used for laboratory heat baths, while Allcosil 200/12,500 can be used as a hydraulic fluid. Silicone oil can come in industrial grade, food grade and cosmetic grade. The common viscosities of Allcosil 200 are 20, 100, 200, 350, 1000, 12,500, and 60,000 (the full range and further information can be seen in our previous blog)

Silicone Emulsions

Basic Info

Silicone emulsions contain 3 components silicone oil, emulsifier and water. The silicone oil provides the desired characteristic, most often lubrication. The emulsifier binds the silicone oil with the third component, water, so that the oil is suspended in solution and can be diluted down easily. The emulsifier-bound oil forms microscopic droplets of a uniform size in the water, which thanks to Brownian motion are kept at roughly an even distance apart.

As long as the droplets remain in this suspension the emulsion will be in good working order, however if the droplets are allowed to rise to the top of the solution (‘Creaming’) form into small clusters (‘Flocculation’) combine into large droplets (‘Coalescence’) or form a continuous layer on the solution’s surface (‘Breaking’) the emulsion will cease to work (see below for a good schematic).

If any of these problems occur, we at J. Allcock & Sons will be able to help solve the problem. We have our own stabilizing agent (Allcosil Stabilizer) that can resolve most emulsion separation issues.

Taken from:


Silicone emulsions are mainly used as a lubricant. One such use is as an anti-nesting agent for the thermoplastic container industry, another as a mould release agent in the rubber industry. Wherever a small amount of silicone oil is needed (usually in ppm) silicone emulsion is the best product.

Our Range

We have a wide range of silicone emulsions available. Allcosil 35 is a 35% silicone oil emulsion suitable for industrial use, while Allcosil 356 and Allcosil 435FG are food grade 35% emulsions. A 60% Silicone oil emulsion suitable for industrial use (Allcosil 60B) may be useful if a smaller dilution is required. We also supply high viscosity oil emulsions, if you wish to use higher centistoke oil in your emulsion (Other emulsions are available) Again our previous blog post has more information on emulsions.

Silicone Antifoam

Basic Info

Antifoams use the intrinsic property of silicone oil to lower water surface tension to pop bubbles and eliminate foam (see below) Silica particles are also present to help pop bubbles through physical piercing.

Taken From:


Silicone antifoams can be used wherever foams form and need to be removed. When solutions are pumped through a high pressure system, soaps are used, or froth is generated by chemical or biological action e.g. in sewage treatment, antifoam can be used to totally remove foam from the solution.

Our Range

As only tiny amounts of silicone are needed for the antifoam effect, J. Allcock & Sons provide two main products, A.011 and Allcosil 30G Antifoam, 10% and 30% silicone based antifoams respectively. We also provide food grade antifoams for the food industry, both 10% and 30% available.

I hope this helps in any Silicone-based queries you may have. If you’d like more information or are interested in any of our products please call myself on +44 (0)161 223 7181

Matt Darlington

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.