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  • What's the Difference Between Natural and Synthetic Rubber?

    Natural and synthetic rubbers are essentially two halves of the same whole. But each half brings properties, advantages and uses unique to that type of rubber. Natural rubber conveys imagery of rubber trees tapped in the depths of the rainforest while synthetic rubbers call to mind traditional manufacturing and oil processing. 

    Is one type of rubber better than another? Are you better off going au natural or keeping things a bit more artificial? Let’s start with an in-depth look at both options.

    What is natural rubber?

    Natural rubber is a rubber material found in nature. It is produced by tapping trees, similar to maple syrup, not by processing oil. Over 2,500 different kinds of trees produce latex, but the most common is the aptly named rubber tree. Latex emerges from the tree in a thick, milky sap which is then processed. Processing typically involves removing excess water and leaving the natural rubber in smokehouses or outdoors to air dry. It is then placed into bales and shipped to manufacturers. 

    Natural rubber dates back thousands of years to civilizations like the Inca, who would use rubber to make balls for ancient sports. Back then, the biggest downside to natural rubber is that it would start to melt or get sticky when the temperature got too warm. It wasn’t until 1839 that Charles Goodyear accidentally dropped rubber on a hot stove, then went on to patent the process of vulcanization to better stabilize natural rubber and keep it intact. 

    Today’s natural rubber usually comes from rubber tree plantations. Rubber trees six years or older can be tapped annually for around 24-30 years. Some farmers prefer to tap more intensely early on while others tap latex as long as possible. There has also been a movement in the past decade for rubber tree plantations to move toward more sustainable practices, a movement which is still developing worldwide.  
     

    Uses for natural rubber

    Natural rubber is used as a raw material in a wide variety of over 10,000 consumer products. Applications include:
     
    • Tires for cars and aircraft
    • Surgical gloves
    • Rubber bands
    • Medical devices
    • Clothes
    • Motor mounts
    • Pacifiers and children’s toys
    • Balloons

    What is synthetic rubber?

    Synthetic rubber, simply put, is any type of rubber that cannot be classified as natural rubbers. Synthetic rubbers are produced artificially by creating polymers via solution polymerisation or emulsion polymerisation. 

    With so many different types of synthetic rubbers available on the market, it’s difficult to generalize them all as one category of rubber with similar properties. The common denominator is that they are all byproducts of oil. But the diversity in synthetic rubbers means many different types are produced using different formulas, and each type has different properties designed to suit different applications.

    Fun Fact: Chewing gum was made with natural rubber until after World War 2, when synthetic rubbers like polyethylene and polyvinyl acetate were developed as an alternative. Natural rubber gum is making a comeback, but today’s mainstream gum brands usually include some sort of synthetic rubber ingredient. 
     

    What are the Different Types of Synthetic Rubber?

    Uses for synthetic rubber

    Synthetic rubbers have a wide variety of uses, and can be found in almost every conceivable rubber application, especially considering some people are allergic to latex and require synthetic alternatives to natural rubber products. Applications include:
     

    Is natural rubber more expensive than synthetic?

    Natural rubber is sometimes more expensive than synthetic, but not all the time. Cost is extremely variable, based on several different factors. 

    Natural rubber comes from trees. If one plantation plants more trees one year, then eight years later they may produce a surplus of natural rubber. Another plantation may have a bad year for crops, leading to a future shortage of natural rubber the market won’t feel for years. Because natural rubber is considered a commodity where many different sources are creating the same or equivalent products, natural rubber is the only raw material in the industry that can be traded on a futures market.

    Both types of rubber, natural and synthetic, are also vulnerable to demand-side factors, including how many manufacturers and distributors are interested in purchasing rubber products in a given year. This is illustrated especially in the automotive market. If more cars are produced, more rubber will be needed to create tires, for example. 

    Numerous factors, especially the volatility of natural rubber, mean the price is sometimes unstable and always difficult to predict. Some sources will say synthetic rubber is more reliably inexpensive, but in our experience, prices are not stable enough to declare one type cheaper than another overall. In fact, in many products or applications, natural rubber and synthetic rubber are combined in a formula, and the mix ratio can be changed relatively easily. This helps keep some synthetic prices in line with natural rubber. 
     

    Should you use natural rubber or synthetic rubber?

    Like many things in the rubber industry, it depends. Though they may seem like the only two options in the umbrella of rubber types, one look at the different properties of each type of rubber shows that comparing natural and synthetic rubber is not always simple. 

    Both natural and synthetic rubbers can be great insulators, non-reactive and work well as adhesives or coatings. However, which one to use depends entirely on your application and the type of natural or synthetic rubber that will work best. 

    One of our favorite metaphors is comparing natural and synthetic rubber to sports shoes. There’s no one sneaker perfect for every sport. Track shoes are best for gripping the track, basketball shoes are good for running the court and soccer cleats are great for getting a grip in unstable turf. In the same way, there’s no one best type of rubber for every application. Each type has its own advantages and drawbacks.

    That being said, it is possible, and not at all uncommon, to combine natural rubber with some synthetic rubbers in formulas that can take advantage of multiple characteristics. Talk with us to determine which formula is best for your application.
     

    Advantages of synthetic rubber

    Broadly speaking, synthetic rubbers generally have several advantages in comparison to natural rubber, including:
     
    • Temperature resistance
    • Chemical resistance
    • Weather, ozone and sunlight resistance
    • Better flexibility at lower temperatures
    • Better electrical insulator 
    • Price and supply not affected by  on weather, crop health or rubber plantation stability 

    Advantages of natural rubber

    It’s difficult to compare natural rubber to the vast expanse of synthetic rubber options, but it does have a few general advantages, including:
     
    • Excellent tear and abrasion resistance
    • Very low compression set values
    • Good vibration dampening characteristics
    • High tensile strength
    • Good adhesion to itself and other materials
    The following table shows some of the properties of natural rubber in comparison to several synthetics:
     
    MATERIAL ABBREVIATION VIBRATION
    ISOLATION
    RELATIVE PRICE TEMPERATURE RANGE OZONE, UV RESISTANCE OIL RESISTANCE
    Natural NR Excellent Good -60F to 220F Poor Poor
    Butyl IIR Excellent Fair -75F to 250F Good Poor
    Ethylene-Propylene EPDM Good Excellent -70F to 250F Excellent Poor
    Nitrile NBR Good Good -30F to 250F Poor Excellent
    Neoprene / Chloroprene CR Excellent Excellent -60F to 220F Good Fair
    Silicone VMQ Good Fair -175F to 450F Excellent Fair
     
    When selecting any type of rubber material, the key thing is to understand the final product’s application and desired characteristics as well as the environment it will be in. From there, you can pick the most cost effective polymer that meets your requirements.

    Not sure what type of rubber is best for your application? Custom Rubber Corp. has decades of experience in helping customers select the best, most cost-effective option for their business needs. Get your rubber materials questions answered by a team of experts today. 

     
    Posted Wednesday, May 12, 2021 by: Global Administrator
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  • Custom Rubber Corp. Upgrading and Expanding

    The Holidays brought new presents to Custom Rubber Corp.  A total of four new machines arrived December 23rd, just in time for the Holidays!
    Some of the machines are additional capacity, some are upgrades to machines that were old and needed to be replaced.  Custom Rubber Corp.'s commitment to our customers and our employees is to continuously upgrade our equipment to make sure every machine we run is dependable easy for operators to use.
     

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  • Custom Rubber Corp.'s Innovative Use of Vision Technology

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  • Rubber News article: Custom Rubber Corp. hosts ARPM Tour

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  • Custom Rubber Corp. Tour

    On September 26, 2018, Custom Rubber Corp. hosted a tour of High School students from Warrensville Heights High School.  The students are in an Engineering and STEM class.  The students learned a bit about what makes manufacturing in general exciting and also some specifics about molding rubber.  At the end of the tour, the students were given a project....

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  • Custom Rubber - Building the Next Generation

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    Custom Rubber Corp. was featured in an article in the most recent Inside Rubber Magazine.  The article discusses the continuous improvement approach that Custom Rubber Corp. is taking with Mill Drills and Safety.

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    Custom Rubber Corp. just updated and added information to the Round Molded Gasket / Round Molded Seals page.  The information includes the three primary ways to produce a round gasket or seal and what the advantages and drawbacks are to each.  Also discussed are three primary technical issues that are important to selecting the right type of round gasket and/or round seal.

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    Custom Rubber Corp. added content to its website with a host of information about molding colored rubber.  The information includes five reasons why Custom Rubber Corp. is one of the leaders in molding colored rubber products and four reasons why product developers, engineers, and companies in general should consider specifying a color other than black for their next rubber molded component. 

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    Custom Rubber Corp. has added detailed, step-by-step information regarding how to design a custom silicone rubber protective case for your electronic device or instrument.

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  • Rubber Bellows Design How-To

    Custom Rubber Corp. added information related to designing molded rubber bellows and molded rubber convoluted boots.  Information is now available on the five steps or questions that designers need to consider when developing a custom molded rubber boot or bellow.

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  • New Look For Molded Rubber Products Website

    We're very excited about the recent launch of our new website. Much of the content is carried over - our old site had excellent illustrations of the types of products we make and customers we serve - but the look and feel of the site is much more up to date. We've included some larger photos showing some of our employees at work and have updated many of the product pictures.

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