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Rubber Material

Neoprene-vs-Nitrile-resized-1
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Do You Know The Difference Between Neoprene & Nitrile (NBR) Rubber ???

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Many Rubber product manufacturersrely on various types of synthetic rubber due to various reasons. The demand for synthetic rubbers over natural rubber has increased very rapidly over the recent past. There are many types of synthetic rubber and they are broadly classified into two categories, namely; general-purpose synthetic rubbers and special purpose rubber. General-purpose rubbers are more common and widely used in many manufacturing processes. Neoprene and nitrile rubber are two such widely used general-purpose rubbers. The key difference between neoprene and nitrile rubber is that neoprene is produced by emulsion polymerization of chloroprene (2-chloro-1, 3-butadiene), whereas nitrile rubber is produced by emulsion polymerization of copolymers of butadiene and acrylonitrile.

Nitrile and neoprene exhibit similar properties, but with differing characteristics that make them useful for different applications. Both materials are elastic, and will return to their original shape when stretched. Nitrile is particularly resistant to chemicals, abrasion, and temperatures, while neoprene is valued for its weather resistance and durability.

What’s the difference between nitrile vs. neoprene for seals, gaskets, and insulation? Both elastomers provide good resistance to compression set and tearing. They withstand the same range of service temperatures, too. Some grades of neoprene offer excellent resistance to abrasion, but nitrile is known for its abrasion resistance at elevated temperatures.

Nitrile and neoprene rubber have many similarities, but there are some important differences between these elastomers. Below we provide a more in-depth look at the properties and advantages of nitrile and neoprene and their industrial uses.

PROPERTIES                  

NITRILE

NEOPRENE

ELONGATION400% to 600%100% to 800%
HARDNESS35 to 9015 to 95
COMPRESSION SETGoodGood
ABRASION RESISTANCEGood to ExcellentVery Good to Excellent
CRACKING RESISTANCE  GoodGood to Very Good
TEAR RESISTANCEGoodGood
FLAME RESISTANCEPoorVery Good to Excellent
MINIMUM TEMP.-34° C to -56° C-34° C to -56° C
MAXIMUM TEMP.+104° C to +137°C+104° C to +137° C
WEATHER RESISTANCEPoorGood
SUNLIGHT RESISTANCEPoorGood to Very Good
OZONE RESISTANCEPoorGood
OXIDATION RESISTANCEGoodGood
WATER RESISTANCEGood to ExcellentExcellent
STEAM RESISTANCEFairPoor to Good
GAS PERMEABILITYFair to GoodFair to Good
CHEMICAL RESISTANCE                                           Generally resistant to Gases, Aliphatic Hydrocarbon, Oils and Fuels Generally resistant to Moderate chemicals and acids, ozone, oils, fats, greases, and solvents
NO CHEMICAL RESISTANCE                        Generally attacked by Ketones, Ozone, Sunlight, Aromatic Oil, Flame, Weather                                                                                        Generally attacked by Esters, ketones, and chlorinated, aromatic, and nitro hydrocarbons

Also read: A Guide To Know The Difference Between Silicone Rubber & EPDM !! 

Nitrile Vs Neoprene Applications

Nitrile rubber is recommended for applications that require oil and fuel resistance, abrasion resistance, and temperature resistance up to 280° F. In mobile equipment and military vehicles, nitrile seals or gasketsare used in carburetor diaphragms, fuel systems, and hydraulic hoses as well as a popular option for highly durable and disposable medical gloves. Nitrile also supports rubber-to-metal bonding, which makes it a good choice for applications in the processing industry. Yet nitrile isn’t recommended for sealing and insulation that requires resistance to fire, sunlight, ozone, or weather.

Neoprene rubber resists fire and withstands sunlight, ozone, and weather. Specific grades of neoprene can also meet flame, smoke and toxicity (FST) requirements for the mass transit industry. Applications include door seals, window seals, hose covers, vibration mounts, and shock absorbers. Neoprene is also used with HVAC units, electrical or electronic enclosures, and weather stripping for fire doors. Neoprene noise isolators are used to reduce sound vibrations from power transformers. Additional applications include expansion joints and bearing pads in built structures.

Compound selection is critical because choosing the wrong rubber can cause more than just a component-level failure. Depending on your application’s specific needs and requirements, both nitrile and neoprene offer a variety of benefits. 

 

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Is Rubber Better Than Plastic ?

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In the past, people have seen the progress of technology. From the simple usage of wood and cement to the invention of metal, mankind has really made great progress to become what they are today. Along with this progress are some changes to their lifestyle. These changes were brought about by the materials surrounding them, and two materials that revolutionized man’s life today arerubber and plastic.

It is quite easy to differentiate between the two. By simply looking at each material, one can immediately tell that a particular thing, or object, is made of rubber and not plastic, or vice versa. The only confusion between the two is when the term polymer is used. Yes, a polymer as a term that greatly denotes plastics, but nonetheless, this term also describes the characteristic of rubbers. Although rubber is more of the specific elastomer (a viscous or elastic variation of polymers), it is still considered to be a polymer for example, CR (chloroprene rubber, neoprene); SBR (styrene butadiene rubber); NBR (nitrile butadiene rubber); and EPDM (ethylene propylene diene methylene).

Certain plastics such as PVC(poly vinyl chloride) and polyethylene can be compounded and cured to have properties that are considered rubber-like. PVC is commonly used in rubber flooring. Vulcanization is an irreversible chemical process which transforms the putty-like, dough-like, or chewing gum-like rubber into a product that has tensile, elongation and memory similar to a rubber band. This amazing transformation from one physical state to another is what makes rubber different from plastic.

Plastics are usually thought of as thermal plastic materials. In other words, when they get hot they soften, and when they get cold they harden similar to candle wax. Rubber, however, over a much higher and lower temperature range will maintain its original room temperature physical properties such as elongation, memory, tensile and hardness. Rubber is tough, holds shape once formed, even at high temperatures. It stretches, snaps back, has good tensile strength and is medically safe, soft, pliable, and pure. It is used to make Sealing products like o rings, washers, seals, grommets, bush etc., automobile tires, rubber bands, sealing gaskets for food boxes, stoppers for medical industry & various other products for a wide range of industrial applications.

Whereas, Plastic has no stretch, it is not pliable, is brittle, and cracks easily. Plastic does not typically have great strength, can’t withstand dishwasher heat. It does not have a good temperature range, does not stretch and is lightweight.

When it comes to choosing the right materials for our products, we always do our research. We want to make sure you’re getting the safest, highly durable, heat resistant, non-toxic & most eco-friendly options for your products. That’s why, when we were creating our leak-proof sealing solutions, we chose rubber over plastic.   

CHARACTERISTICS                                         

RUBBER                                                                                                                            

PLASTIC

ENVIRONMENT SAFETY

BiodegradableNon Biodegradable

DURABILITY

Highly DurableCracks Easily

RECYCLABLE

YesYes

HEAT RESISTANT

Highly heat resistantCan’t resist heat melts easily

HARDNESS

40- 9020-100

ELONGATION STRENGTH

High elongation StrengthDoes not Stretch

LEAK PROOF

Can be molded to any shape, can stretch & fit into any component.Cannot provide sealing as it is hard, cannot stretch & break easily
FDA COMPLAINTYesNo

Rubber is durable, and more eco-friendly than plastic. It lasts longer, and stands up better against heat and cold than plastics. It’s safer for your products, too, with no estrogen-mimicking toxins like BPA to worry about. It is odorless, stain-resistant, hypoallergenic, and has no open pores to harbor harmful bacteria. 

Rubber is recyclable, even though you might not be able to leave it with your curbside pick-up, and it can be incinerated safety without toxic off-gassing. When burned, silicone reverts back into its harmless ingredients: amorphous silica, carbon dioxide, and water vapor (unlike plastic which releases toxins when burned).

Thankfully, you won’t have to worry about rubber breaking or cracking for a long time! It’s super durable, resisting melting, breaking, and warping. Chances are our sealing products will outlast for a longer period of time. 

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Do You Know The Ways To Prevent Failure Of Rubber Parts ???

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Rubber is probably one of humanity’s greatest inventions, it is a very useful & malleable material but chances are something made of rubber has let you down at some point in your life. Like most  elastomers rubber will also undergo significant changes over time when exposed to heat, light and ozone.These changes can have a dramatic effect on the service life and properties of the rubber products also can impair the functionality of critical rubber parts, like seals, O-rings, washers, gaskets etc. and could lead to machine failure which can of course have potentially catastrophic consequences. Read on to find out more about typical rubber deterioration causes and practical ways to prevent rubber deterioration.

What is Rubber Deterioration?

Natural rubber and synthetic elastomers deteriorate on aging as a result of the contribution of a number of factors. It has been generally recognized for many years that the changes in properties on aging are due primarily to the deteriorating effects of one or more of the following factors: heat, light, oxygen, and ozone. Some non oxidative thermal changes are involved but the effects of heat and light are for the most part a result of their effect upon the oxidation reaction. Oxidative and thermal ageing of rubber are accelerated by stress and reactive gases, like ozone, resulting in cracking, charring and color fading. However, the addition of antioxidants, UV stabilizers and antiozonants can slow or prevent these types of issues.

Oxidative rubberdegradation can cause hardening or softening, depending on the structure of the elastomer. Hardening is more common because free radicals produced due to heat, oxygen and light combine to form new crosslinks, which reduces the flexibility of the rubber. Although the general mechanism of autoxidation is well understood, the actual chain scission and crosslinking steps are often unknown. They depend on the composition of the rubber including concentration of accelerators, activators, and fillers as well as on the temperature and composition of the atmosphere. 

How does Rubber Products deteriorate?

Natural rubber and synthetic elastomers deteriorate on aging as a result of the contribution of a number of factors. It has been generally recognized for many years that the changes in properties on aging are due primarily to the deteriorating effects of one or more of the following factors: heat, light, oxygen, and ozone. Some non oxidative thermal changes are involved but the effects of heat and light are for the most part a result of their effect upon the oxidation reaction. Thus oxygen in the form of O2 or O3 is the primary cause of deterioration of elastomers. Rapid combination with ozone is a characteristic reaction of unsaturated organic compounds. 

Also Read: Causes of Rubber Parts Deterioration

The two main forms of rubber degradation are: hardening (or embrittlement) and softening. From a molecular perspective, these chemical processes are known as “chain hardening” and “chain scission” respectively. The chemical makeup of the polymer will determine which type of deterioration will ultimately occur. For instance, the polymer polybutadiene and its copolymer derivatives – such as styrene-butadiene-styrene (SBS) and nitrile rubber (NBR) – is developed using a process called cross-linking, which involves joining polymer chains together to form one single molecule. Free radicals produced by heat, oxygen and light combine to form new crosslinks, which reduces flexibility and leads to hardening. This is chain hardening.

Natural rubber (polyisoprene) and other isoprene polymers, on the other hand, are susceptible to chain scission. These types of rubber are developed using polymerization, which entails bonding multiple identical molecules – or monomers – to form a polymer. As such, their polymer main chain is liable to degrade, which is the act of chain scission, and leads to the softening of the rubber material.

How can we prevent rubber products from deterioration ?

DMA Analysis:

Even before a rubber product is manufactured, a technique known as DMA (Dynamic Mechanical Analysis) can be used to predict a rubber material’s response to stress-strain conditions. DMA stress analysis illustrates whether a proposed design will function to design specifications prior to manufacturing a mould tool.

After Ageing Properties:

Apart from DMA Ageing properties were tested according to the ASTM D573-99 Standard Test Method for Rubber – Deterioration in an Air Oven. The tensile and physical properties namely hardness, tensile strength, elongation at break, modulus 300%, tear strength were measured before and after ageing for each aging time. This can help to prevent rubber deterioration in the long-term and provide significant cost-savings.

Ozone Testing:

When ozone comes in contact with rubber, the double and triple chemical bonds are attacked causing the cracking that is commonly seen on the surface of some rubber products. Conducting controlled, laboratory Ozone Testing of material samples against industry standards also provide us critical information needed to make formulation decisions.

Compound Designing:

Rubber compounds are complex mixtures of polymers, reinforcing fillers, oils / plasticizers, curatives, stabilizers, and other additives that are combined in relatively quick mixing processes. Durability is impacted by all these ingredients, their interactions, and the quality of the mixing. By Compounding  Designing we are able to find out the correct proportion & composition of mixing various compounds in order to prevent the deterioration of our sealing products such as O Rings, Gaskets, Washers, Grommets, Bellows, etc.

Related Post: 5 Essential Considerations Before Designing Rubber Products !!!

Addition Of Antiozonants & Other Additives:

Apart from above methods & techniques the problem can be prevented by adding antiozonants to the rubber before vulcanization. With the help of additives rubber deterioration can be prevented. A common and low cost antiozonant is a wax which bleeds to the surface and forms a protective layer, but other specialist chemicals are also widely used.

On the other hand, the problem does recur in unprotected products such as rubber tubing and seals, where ozone attack is thought to be impossible. Unfortunately, traces of ozone can turn up in the most unexpected situations. Using ozone-resistant rubbers is another way of inhibiting cracking. EPDM rubber and butyl rubber are ozone resistant, for example. For high value equipment where loss of function can cause serious problems, low cost seals may be replaced at frequent intervals so as to preclude failure.

With the right rubber restoring techniques, and a sufficient level of care and maintenance, rubber seals or products of certain polymer types can often be brought back from the brink of failure and restored to functionality. 

To know more in depth about how to improve service life of rubber parts read our another blog

High-Temperature Sealing Applications
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5 Most Suitable Materials For High-Temperature Sealing Applications !!!

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Industrial Rubber Seals are designed to prevent leakage, while helping to combine systems or mechanisms together. While seals created for ambient and low temperatures are not extremely difficult, creating seals for high temperature applications is a challenge. This is because standard sealing materials cannot perform well in such conditions for long periods of time. As excessive heat can gradually degrade rubber materials, leading to deteriorating performance and premature failure. This can result in leakage & high-temperature applications require high-temperature-resistant rubber products that offer dependable performance no matter what. Hence, it is important to choose the right manufacturing materials to ensure prolonged seal performance in high temperature applications.

Applications with high temperatures can include ethylene production, steam and gas turbines, solid oxide fuel cells, and industrial exhaust systems. Such applications comprise immense levels of heat, aggressive chemicals, and strong transfer fluids. Due to these elements, the temperatures can be of at least 400⁰F or above. Traditional sealing materials like mica or graphite lose their physical integrity, and their performance diminishes quickly in such environments. This can result in total leakage, which can lead to a shutdown, and downtime.

Silicone Rubber

A rubber-like polymer, Silicone Rubber has a high temperature resistance up to 230⁰. It offers outstanding high-temperature resistance, with some compounds able to withstand temperatures up to 305 °C. The material is resistant to UV rays, ozone, and oxygen. It has great electrical insulation properties, and high gas permeability. It is mainly used to manufacture aerospace seals, and automobile gaskets.

Silicone is not a high strength material and tears easily. Having said that, we have special compound grades that deliver better tear resistance than standard silicone. Fluorosilicone elastomer material combines high liquid resistance of fluorocarbon, and extreme temperature stability of silicone. With a temperature above 400⁰F, fluorosilicone O-rings can be exposed to sunlight, and will not degrade due to air, ozone, aromatic, or chlorinated hydrocarbons.

PTFE

Polytetrafluoroethylene is one of the reliable polymer materials. It can resist strong industrial chemicals, and maintain its integrity in temperatures above 500⁰F for long time periods.PTFE provides the least amount of friction when compared to other options. In addition, PTFE is tremendously nonwetting and acts as an excellent electrical insulator. PTFE is also unfazed by the majority of chemicals. It is extremely resistant to high temperatures, contain outstanding electrical properties, have excellent release surfaces and superior chemical resistance. PTFE is widely used across various industrial applications like Plumbing, HVAC, Electronic Appliances, Pharmaceutical, Automotive & many more.

FKM (Viton)

FKM is a family of fluoroelastomers commonly referred to by DuPont’s Viton® brand name. FKM is an excellent high-temperature-resistant rubber that can resist the temperature above, which retains its good mechanical properties and chemical resistance (oils, fuels, lubricants and most mineral acids), even at extremely high temperature up to 225⁰F. Due to its wide temperature range, chemical compatibility, low compression set, and excellent aging characteristics, fluorocarbon elastomers (FPM, Viton®) have grown to major importance in the seal industry. Fluorocarbon elastomers are highly fluorinated carbon-based polymers used in applications to resist harsh chemical and ozone attack. Fluorocarbon O-ringsshould be considered for use in aircraft, automobile and other mechanical devices requiring maximum resistance to elevated temperatures and to many fluids such as mineral oils and greases,  non-flammable hydraulic fluids, silicone oil, fuels etc. Whilst not recommended for use with brake fluids, ammonia solvents, strong acids or superheated steam.

EPDM

EPDM – also known as ethylene propylene diene monomer – is an extremely versatile material used in a variety of applications, from automotive products to HVAC parts. This type of rubber also acts as a less expensive alternative to silicone, as it can endure weather conditions, abrasion, and other challenges for long periods of time with proper use. EPDMis a copolymer of ethylene, propylene and diene monomers. This synthetic high-temperature-resistant rubber offers excellent heat resistance, performing optimally up to +150°C. It has good resistance to UV exposure, ozone, aging, weathering, and many chemicals – great for outdoor applications. Can be fabricated in a variety of ways, which includes custom molded and extruded partsLong-term part lifespan allows for fewer replacement parts, saving money in the long run. 

Also Read: What Are The Advantages Of EPDM O Rings?

HNBR

HNBR elastomers are changing the game for sealing and manufacturing companies. Made from hydrogenated acrylonitrile butadiene rubber (NBR), the compound meets higher temperatures, retains better resistance and has become widely known for its physical strength. It is a unique elastomer that is derived from conventional nitrile rubber through the hydrogenation of unsaturated bonds in the butadiene. HNBR is an exceptionally high-temperature-resistant rubber that can withstand much higher temperatures than conventional nitrile up to +150 °C. It also offers good abrasion resistance. It is resistant to mineral oil-based hydraulic fluids, animal and vegetable fats, diesel fuel, ozone, sour gas, dilute acids and bases. HNBR also resists new bio-oils (biological oils). Typical applications include gaskets and seals, especially for the oil and gas industry, and accumulator bladders, and diaphragms. It is compatible with automotive oils, gases and fuels such as aliphatic hydrocarbons, hydraulic fluids and dilute acids. However, HNBR is not recommended for use with chlorinated hydrocarbons, polar solvents or strong acids. Also note that it has limited resistance to brake fluids.

How To Check The Material Grade
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How To Check The Material Grade/ Impurities/ Quality etc. !!!

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When it comes to predicting the durability or performance of a given material for use in a specific application, it’s crucial to evaluate chemical and physical properties as well as environmental compliance and quality control. At Kesaria Rubber we understand the real-world service-life and environmental challenges polymer materials face. Our experts can help you predict, manage and improve the performance of your polymer-based material or product whilst ensuring its safety and compliance. We provide independent rubber material analysis to clients operating in a wide range of industries.

We help clients understand, manage and improve the performance of their materials and products using a range of analytical techniques together with expert interpretation of results, guidance and advice. We go through a comprehensive range of chemistry, physical testing, and technical consulting stages to support the development of polymer based materials and end products. 

  • Chemical Characterization

When working with new compounds and sustainable, recyclate-based material formulations – gaining full confidence in their performance requires accurate assessment of not only physical and mechanical properties but also the identification and mitigation of any contaminants.

How we check the Material grade/Polymer Identification

Proper material selection is at the heart of any product or development project. Material characteristics and performance can determine the success or failure of the productand consistency of the rubber materials from lot to lot plays a significant role. Below are a few tests by which we can check the material/ identify the material and check the consistency of the quality of the rubber material. Following are the methods we use for chemical testing-

1.0Chemical methods ( ASTM D 297 )

  1. Burning Test: The piece of sample is heated in a flame and the odor and the color of the flame is noted.
  2. Acid degradation test:
  • Action of 80% H2SO4 and heated slowly in the flame.  The change in sample condition is observed.
  • Action of Concentrated Nitric Acid:  A small piece of width approximately 2-3 mm is taken in the test tube containing 1-2 ml of concentrated HNO3 and heated slowly in the flame.  The change in sample condition is observed.

      3. Beilsten test (Cu Wire test): The copper wire is heated till red hot; the sample is taken on the red-hot wire and heated in the flame. The color of the fame is then noted.

2.0 Instrumentation methods

    1. FTIR:     Fourier Transform Infrared Spectroscopy (FTIR)
    2. GCMS:   Gas Chromatography Mass Spectrometry (GCMS)

  • Physical Testing

Rubber material formulations can be greatly affected by a wide range of environmental conditions and physical forces. From adhesives to a variety of rubber compounds, Kesarias’ physical testing experts can provide guidance and test data to support your material evaluation needs. Our environmental exposure capabilities include variables such as temperature, humidity & UV Arc chambers to test in the harshest of lab conditions. Physical properties can be studied extensively through a myriad of internationally recognized standard test protocols. While data from any combination of these material property tests can provide you with a good picture of a given material’s expected performance.In addition, Kesarias’ laboratories are able to not only excise samples from most whole products, but our internal small batch mixing and molding capabilities can assist you in providing the most appropriate samples for your testing purpose.

How we check impurities and quality of rubber

  • Density: ASTM D297

The specific gravity of any elastomer is important for its identification and providing an approximate measurement of its physical properties. Rubber density determines the specific gravity of the material and Generally the S.G. of rubber is used in place of density which is measured with respect to water. Specific Gravity is normally abbreviated to SG and is the ratio of the weight of a given substance to the weight of an equal volume of water at a specified temperature. If the Specific Gravity increases from its standardized value then it seems that rubber material has impurities or fillers which will affect material properties.

Procedure:

The most common method of determining the density of a rubber material is to weigh a test piece in air and water. Weighing in air provides the actual weight and weighing in water provides the volume. The density is then calculated by dividing the weight by the volume.

 

  • Ash content (ASTM D297_Filler Analysis)

The quality of rubber varies widely due to the percentage of ash content into it. Rubber materials having Inorganic impurities like Silica, Zinc Oxide, Clay etc. and high concentration of these impurities or high ash content % may initiate the oxidative degradation of rubber and may affect the quality of the final product. The percentage of these impurities can be found out by an ash content test. This test method is used by the rubber industry to ensure purity of the ingredient as per standard specification.

Lower Ash Content 

(Virgin Materials/Lower Impurities)

Longer service life.

 

Higher durability.

Lower after sales services.

 Procedure:

Ash % is determined by taking an accurately weighed sample in a properly cleaned porcelain crucible and heating   in a muffle furnace at 550 + / 25 °C for 1 hrs. The crucible is then cooled to room temperature and final weight is taken after getting constant weight. The mass of residue in the crucible represents the Ash Content. The ash content is calculated as per given formula i.e.

Ash content % =   Weight of the ash

                            _________________        x 100

                            Weight of sample taken 

 

  • Life Prediction & Accelerated Ageing

Life prediction and accelerated aging studies to help you make significant, safe and effective material choices, supported by material analysis for your intended end-use application. Life prediction and accelerated aging can be assessed throughout the product cycle from material evaluation, product development, and material qualification through to prototype design and final product stages. As service conditions become increasingly more demanding there is a need to demonstrate material durability and ensure a material is fit for purpose. Testing materials and products exposed to accelerated high temperature aging enables product service life predictions to be evaluated.

Prediction of expected product life time

Kesaria Rubber Industries helps generate data to drive product improvements. Polymer material performance is dependent on time, temperature, stress and environmental factors which can all be investigated with the following testing:

  • Mechanical (creep, fatigue, stress relaxation, impact, environmental stress cracking (ESC) and wear)
  • Thermal (degradation, dimensional stability, fire)
  • Oxidative (oxygen, ozone and metal catalyst)
  • Chemical (fluids, gases, water and steam)
  • Radiation (sunlight, ultraviolet light and atomic radiation)
  • Biological (microorganisms)
  • Electrical (arcing, electrostatic build up, dielectric breakdown)