How to Bond Unknown Rubbers & What Adhesives to Use

Table of Contents

People often ask me what I do for a living. When I say that I work for an engineering company stickers, more often than not I am presented with an empty look and the question: “what’s that?” I answer “you know, glue, sticks stuff together …” “Ah, Yes, glue … “, then they quickly change the conversation.

So when someone needs advice on rubber bonding, given the lack of knowledge, excitement and interest in glue, I do not know where to start with the selection of adhesive. Then play into the mix that they are not a rubber / materials specialist and they are really frustrated.

 

 

Types of Rubber

Now, I am no rubber expert and struggle to identify one type to another as well, but here are some basic types:

ACRILONYTRILE BUTADIENE RUBBER– this is very common and can be found frequently in applications such as hoses, O-rings, gaskets, conveyor belts, cable coating and printing rollers.

BUTYL RUBBER – This material is very flexible and is used for things like linings, inner tubes, seals and lids, as well as valve seating.

POLYURETHAN EDGE – often used for things like moulding and modelling.

NATURAL RUBBER – often used for mountings and carpet backing.

SILICONE RUBBER – This material has excellent resistance to high temperatures, making it a popular choice for O-rings, gaskets, cookware, kitchenware, medical appliances and prosthetics.

EPDM RUBBER– hoses, seals, etc.

There are plenty of other rubbers like SBR latex, chloroprene, etc … too many to mention.


Rubber Bonding & Rubber Adhesives

Before attempting rubber bonding, it is recommendable to carry out a solvent de-grease. Surfaces may have mould release, slip additives or other lubricant processing on them, so a quick clean using isopropanol is a good idea. Acetone can be very aggressive as certain types of rubber are vulnerable to attack.

Even after you have cleaned the surface, the rubbers may contain plasticisers that can resurface again over time and can cause boning at a later date (but not all adhesives are affected by it, so do not panic!).

Instant adhesive cyanoacrylate is usually your best bet for rubber bonding; Epoxies are not usually recommended – the rubber is easily peeled off.

Cyanoacrylate adhesive cures in seconds, so you can find out very quickly whether it will work or not! Less cyanoacrylate is more to use only a small drop and make sure that the components are pressed together firmly. If the joint falls apart after enough curing time, it indicates that it may be a harder to bond rubber (like EPDM or natural rubber) or could be dealing with silicone rubber.

[su_youtube url=”https://youtu.be/mtOQpZV36ss” autoplay=”yes”]

For EPDM bonding and natural rubber, an easy solution is to simply use a specialised hard rubber adhesive like Permabond 105. This eliminates the need to use a primer cyanoacrylate. For silicone it would be necessary to use a primer such as Permabond POP in combination with 105 or, if a little more desired flexibility, use the cyanoacrylate POP and Permabond 2050.

Permabond 2050 is very useful, especially for bonding together Soft O-rings as it maintains its flexibility in the joint so it is difficult to detect the joint (usually the adhesive may feel a little “crunchy” on the joint, but the 2050 keeps a uniform seal).


Other Bonding options

It may be very restrictive to consider cyanoacrylate adhesives as the only option for bonding rubber; This is not necessarily the case.

The advantages are obviously a good grip (usually to the point that if you try to pull the rubber side link will break) and fast curing speed make cyanoacrylates ideal for fast assembly processes on production lines, but there are drawbacks.

Cyanoacrylates

Do not allow time to re-align the joints due to curing in seconds. In addition, they offer a limited gap fill (maximum 0.5 mm) and cannot extend over large areas (they will bond the spreader or roller). Its pungent odour can be unpleasant.

Contact adhesives

Can be used instead, especially offering a practical solution to large areas (but again, it may be a bit smelly!), But they can also be difficult to realign well. An alternative, low-cost method of joining is solvent based rubber bonders.

Silicone based products – The Best Rubber Adhesive

Can be used for bonding a silicone, but some find them messy and slow to cure, so they are not practical for small item assembly on a fast production line.

Permabond TA4605 and TA4610 are two-part acrylic structures for bonding difficult plastics like polypropylene, polyethylene and PTFE which also demonstrate the quality of designs such as EPDM.

EPDM rubber contains polypropylene, so it is understandable that these products are used to connect this rubber. Structural acrylic adhesives offer the possibility of accurate alignment and spreading due to their slower cure time than cyanoacrylates.

The odour is less pungent than many adhesives, and are not solvent based. TA4605 and TA4610 have excellent environmental durability, therefore they can be used in applications that are submerged in water. In other words, this the by far one of the best industrial rubber adhesives available.

The Best Rubber to Rubber Adhesive

Overall, Cyanoacrylates are the best rubber to rubber adhesive to use for the vast majority of repairs and applications due to their fast cure time allowing you to quickly see whether it will have the desired strength and resistance in the specific application.

Although, as new technologies arise, some are now opting for epoxy adhesives, as new formulas lower cure time and create high strength and durability.

 

For more help and quotation services, please contact Antala.

Share on linkedin
LinkedIn
Share on twitter
Twitter
Share on email
Email
Share on whatsapp
WhatsApp
Share on print
Print

We are your technical partner.

If you have any questions or want to find out more about the possibilities for your industrial application, please complete the contact form and one of our experts will be in touch.

If you have a problem with industrial adhesives, sealants, or electronic protection products and require advice, you can contact our technical support service. Our team can help you to optimize your processes and applications.

Liked this article?

If you found this article interesting please share it using the buttons below.

everything you should know about the EN 45545
everything you should know about the EN 45545 Standard
RELATED posts
Are you looking for a solution?

We are committed to optimizing your applications through our technologies and we advise you without any commitment.

Subscribe to the Knowledge Hub

Sign up to receive more articles like this directly in your mail.

Please be advised

As COVID-19 continues to impact many industries, companies and their day-to-day processes, we would like to assure you that Antala Ltd is classified as an “Essential Business” and is open for business as usual. 

We have implemented our continuity plan to maximise the safety of our employees while still providing critical support, sales, and fulfilment services to our domestic and international customers. 

Please contact us via phone, website or email 

We wish you the best during this difficult period. 

railway whitepaper antala

EN 45545 Railway Applications

This white paper examines the european standard EN 45545 Fire protection for passenger railway vehicles.