How Are Nitrile Gloves Made? The Manufacturing Process ...

Nitrile gloves are multi-purpose chemical-resistant gloves made from synthetic rubber and oils. Nitrile is a type of rubber known for its many use cases. But how do you make nitrile gloves? Let’s take a look at how nitrile gloves are manufactured. We all know that manufacturing processes in any company can get complicated. But it doesn’t have to be so scary or difficult to understand. For example, the process isn’t as complicated as you might think when it comes to manufacturing nitrile gloves. That being said, some components are still involved in making any product, no matter how simple or complex it seems. Keep reading to understand this process better and see what goes into making nitrile gloves.

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Understanding the Manufacturing Process of Nitrile Gloves

Every manufacturing process has a few key steps. These steps can differ depending on the type of product being manufactured, but the general framework is always the same:

1. The materials or inputs phase involves gathering the raw materials that go into making the product.

2. Then comes the processing phase, where the materials are transformed into a usable product through the use of specific machines or tools.

3. Lastly, the outputs phase deals with the packaging and selling of the final product.

The inputs phase, also known as the supply chain, refers to the process of getting the materials or raw materials to the factory. The processing phase, sometimes called the transformation phase, involves changing the materials into a product. Finally, the outputs phase, also known as the distribution phase, refers to the distribution of the finished product after it is made.

Mixing the Raw Materials

The first step of the processing phase is mixing the raw materials. The manufacturers will mix a list of ingredients to create the synthetic rubber used to make the gloves. The main ingredient in nitrile gloves is NBR (Nitrile Butadiene Rubber), but the gloves also contain other chemicals such as sulfur, antifoaming agents, stabilizers, and accelerators. As the name describes, accelerators are used to accelerate the process of making nitrile gloves. Recently some manufacturers have started producing gloves without accelerators to minimize the risk of Type IV hypersensitivity, which accelerators in rare cases have shown to provoke. If you already know that you have Type IV hypersensitivity or simply want the best of the best, look for “Accelerator-Free” or ask your vendor if the gloves are made without accelerators. Click the link to learn more about Accelerator-Free Nitrile Gloves.

Shaping the Gloves

After mixing the ingredients, the next step is shaping the gloves. The manufacturers will transform the ingredients into gloves by using a machine that shapes the gloves. This shaping process can be done in several different ways, depending on the design of the machine. Most production lines have rotating steel rollers with ceramic glove formers mounted.

Starting with a wash, the ceramic hand-shaped formers are dipped in water and bleach to ensure that they are clean and that no residues from the previous production run are present. After the formers are dried, they are dipped in calcium carbonate and calcium nitrate solution to help the synthetic rubber to coagulate. The formers are now dipped in the synthetic rubber mixture (NBR-mix), which coats the formers with what will turn out to be the final glove.

Drying and Solidifying the Gloves

Next, the gloves must be dried and solidified. The gloves are dried in a machine that removes all the water. The gloves are then put into an oven set at a low temperature to solidify them. Any product made with synthetic rubber has to be dried and solidified before it can be used. This is because synthetic rubber is technically plastic, not rubber. This means that it is not yet fully transformed into rubber. It is still semi-liquid, which is why it is called synthetic rubber. To fully transform the synthetic rubber into rubber, the gloves must be dried and solidified in an oven.

Coating and Stripping the Gloves

When Nitrile gloves are produced, two additional processes may be used to improve donning (donning = putting on the glove). These processes are called polymer coating and chlorination. Polymer coating adds a lubricating layer to the glove’s surface, while chlorination makes the material slicker and harder by exposing the glove to a chlorine-acid mixture.

Next is the stripping phase, where the gloves are removed from the formers.

Quality Assurance

Quality assurance is where the gloves are checked for physical and visual defects like pinholes and black or white spots from the production. This kind of test is often referred to as the AQL test. The manufacturers will also verify the thickness of the gloves, chemical composition, and elasticity, which will also be checked for accuracy and consistency. On a scheduled basis, the gloves will be tested to see if they are resistant to chemicals and other elements.

Very often a third-party company is used for tests. We always use SGS or TÜV to make AQL inspections for every batch of PROSENSO gloves.

When all tests are passed, the gloves can be packed in boxes or polybags and sent to the distributors.

Summing up

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The manufacturing process of nitrile gloves is quite simple. Once you know what each step entails, it’s not hard to understand. Once you understand all the different components that go into making a product, you’ll be able to see how everything fits together. Nitrile gloves are a staple within many industries, and they’re used for a wide range of tasks. Nitrile gloves are used by workers in a variety of industries, such as healthcare, automotive, and manufacturing.

What’s so interesting about how disposable gloves are made? Quite a lot, it seems.

We frequently get questions about what’s involved in making gloves. We’ve also published a few blog posts over the years describing the manufacturing process, and they’re always among our most popular.

Thinking it might be handy to tie it all together in one, here goes with an easy-to-read summation of how the process works.

The basic building blocks

There are four primary materials used in making disposable gloves: nitrile butadiene rubber, natural rubber latex, polyvinyl chloride, and polyethylene. Various specialty gloves incorporate other materials, but those four cover everything that AMMEX sells.

1. In glove production, ceramic or aluminum hand-shaped molds, or formers, are first washed in hot water and chlorine to remove all residue.
2. Next, the formers, suspended on a continuous moving chain, are dipped into a mixture of calcium nitrate solution and calcium carbonate—the nitrate is a coagulant, while the carbonate helps the gloves release from the formers.
3. After drying, the molds are dipped into the latex compound, with the duration of the dip determining the mil thickness of the gloves.
4. The freshly molded gloves are next leached in a mixture of hot water and chlorine, which removes residual latex proteins and chemicals to help reduce the severity of any allergic reactions to latex.
5. The gloves are then dried and cured, then vulcanized to convert the gloves to an elastic state by causing a reaction between rubber molecules in the latex and chemicals that have been added. This gives gloves their elasticity so they are less likely to tear.
6. After drying, the gloves are rinsed again to leach out more latex proteins, then the cuffs are beaded, or rolled, to make them easier to don and doff.

Latex is the oldest and most familiar material. In the glove world, it goes back to 1889 at Johns Hopkins Hospital in Baltimore. William Stewart Halstead, the hospital’s first surgeon-in-chief, is credited with developing the first surgical glove. He petitioned the Goodyear Rubber Company to make gloves because his surgical team’s hands were irritated by the chemicals used.

Latex was the standard for the better part of a century, with disposable gloves becoming the norm in the 1960s. Increased use of latex gloves, particularly during the AIDS crisis of the 1980s, raised awareness of latex allergies and brought about the introduction of vinyl and nitrile gloves by the mid-1990s. Those two materials, which contain no plant proteins to cause allergic reactions, have largely supplanted latex, but it still has a devoted following in some uses.

Where latex comes from

Latex concentrate, the raw material used in manufacturing, comes from Hevea brasiliensis, also known as the Pará rubber tree. It originated in the Amazon rainforest and was introduced to Southeast Asia, Africa, and elsewhere in the 1870s. Today most of the world’s natural rubber comes from plantations in India, Indonesia, Thailand, Malaysia, and Vietnam.

Rubber trees are usually ready to be tapped after about seven years of growth. Thin strips of bark are removed from the tree, which makes the milky-white sap run downward into a cup. After about six hours, the fluid stops, usually filling a gallon bucket.

Because of its high water and non-rubber content—about 70% is water, protein, sterol glycosides, resins, ash, and sugars—the latex is concentrated and stabilized. The latex is mixed with processing chemicals including sulfur, zinc oxide, accelerators, pigments, stabilizers, a de-webbing agent, and antioxidants. It matures for 24 to 36 hours to become ready for dipping.

Where nitrile, vinyl come from

The processes for creating nitrile and vinyl materials are similar. The nitrile butadiene rubber (NBR) used for nitrile gloves is a copolymer, which is a substance derived from the bonding of molecules. In the case of NBR, the two parts are butadiene and acrylonitrile, which chemists combine using a process known as copolymerization.

These molecules provide specific advantages for the gloves: Acrylonitrile enhances the chemical resistance, while butadiene creates flexibility and tear resistance.

Polyvinyl chloride (PVC) must be produced at a polymer production facility through the polymerization of vinyl chloride monomers. The raw PVC material then receives a plasticizer, making it soft and pliable; otherwise, the PVC would be rigid, as it is when used to form pipe. It is then sent to a glove production facility.

Once the synthetic materials are prepared, they are added to the production process. With a few exceptions—primarily involving washing and chlorination to remove latex proteins—this process is mostly the same as the steps for manufacturing latex gloves.

The last steps of the cycle include testing the gloves, then boxing and shipping them. You can read more about the testing process in our recent post, Acceptable Quality Level Determines If a Glove Is Industrial or Exam Grade.

Poly is a process all its own

Polyethylene is the most affordable glove material and is used primarily in the food service industry.

It is a polymer that is synthesized from ethylene and a thermoplastic that is formed into various shapes as it cools from a liquid state to a solid state.

Two polyethylene sheets are seamed and sealed with heat to create disposable gloves. Because poly gloves are not dipped like latex, nitrile, and vinyl gloves, they are not impervious to liquids. Vinyl gloves are a suitable alternative for food service tasks where liquids are present.

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