Getting a Grip: The Essentials of Textured Disposable Gloves

Getting a Grip: The Essentials of Textured Disposable Gloves

Here's what companies need to know about textured disposable gloves.

Rubber gloves, including nitrile and latex, have been around for just over a hundred years. Over that period of time, the applications for protection have grown from surgical and medical uses to industrial uses such as assembly, food processing and maintenance. In more recent years, more general applications—such as light manufacturing, gardening and DIY—have grown in demand. With this ever-increasing and diverse demand, various performance properties, such as grip, needed to evolve.

Glove producers began learning from other rubber-based products with specific grip needs, such as tires and running shoes. As tires and running shoes developed multiple treaded patterns designed for various conditions, glove producers and users took note. As with early tires and running shoes, initial glove patterns involved a series of grooves and nodules similar to the tread of a tire.

Ultimately, glove texture developed into more commonly known grip patterns such as raised diamond, fish scale, honeycomb, pebble and sand patch, which were first developed for the palms of heavy-duty rubber gloves used in industries such as poultry processing. Many of the early "canner's" gloves were used to pluck chicken feathers. 

The plucking process utilized a heavy-duty rubber glove with patterns on the palm side of the left and right gloves. In the late 1980s and early 1990s, the thinner, disposable glove makers began to adapt these same patterns into the palms and fingers for their markets. Minor sand patch texture all over the glove evolved to the same texture but was used only on the fingertips. The new millennium brought more traditional diamond and fish scale patterns to the disposable glove market.

Factors Affecting Grip

Before discussing the actual shape and physical characteristics of grip, it is important to understand something that most people don't realize. Glove materials and manufacturing processes are equal to or more critical to grip than the actual grip pattern.

Let's start with the materials used in the product. Natural rubber latex, for example, inherently has a higher tack level than nitrile. Higher tack is another word for higher grip properties. All else held constant, a natural latex glove would have a better grip than a nitrile glove. This is why natural latex is the preferred material of choice for many applications, such as surgical gloves and dishwashing gloves. Surgical gloves require very good grip without a heavy texture to interfere with dexterity.

Manufacturing process steps and the materials used in manufacturing are also very significant to grip performance. Historically, gloves were powdered to prevent them from sticking together. In other words, powder was used to reduce the tack. Later technology evolved to a chlorination process, which dissolves the processing powder and changes glove surface chemistry to reduce tack level. The heavier the gloves are chlorinated, the more slippery they become. So a glove, whether natural latex or nitrile, can be lightly chlorinated and still yield a high tack/grip level regardless of surface texture. Further advances led to polymer and wax coatings to eliminate the need for an offline chlorination process. 

These polymer and wax coatings have variable properties with respect to grip depending on the type and concentration used to manufacture the gloves. Finally, the surfactant type and concentration used in the polymer compound of the base material plays a role. Many nitrile gloves, for example, use a high level of surfactants. If not appropriately leached, these surfactants can be present at the glove surface and ultimately affect grip properties. This is especially the case in wet applications where a soapy residue is seen on the surface of the glove while in use.

Finally, the glove surface texture affects the resulting grip. Patterns include smooth, finger-only, raised patterns such as diamonds, inverted patterns such as lozenge or fishscale, and variations in between. The resulting grip depends on the application and the size, spacing, depth and shape of the texture used.

Understanding Glove Texture

Let's now discuss texture properties with respect to grip. Like tire and sneaker tread, the design of the texture plays a role in grip. Many glove applications require grip against a relatively flat surface. Ever notice how plates of glass are handled? They use suction cup handlers to move and install glass. Ever notice the type of grip below a typical shower mat? It is usually a suction cup. In most applications, a suction cup design offers better grip than a nodule design such as raised diamonds. The level of grip is affected by the shape, size, depth and spacing of the suction cups on the surface.

In addition to the design of the texture, there are other important factors to consider. Texture can create weak spots in the glove. Consider a waffle for a moment. The waffle's ridges are the thickest part of the waffle, while the valley of the waffle is the thinnest part. Certain textures create this ridge and valley phenomenon, leading to very thick and thin spots. If someone were to blow up a glove like a balloon and hold it in front of a light, they would see the thin spots more prominently. This is the case in most raised patterns, such as diamond, and inverted patterns such as fishscale. These very thin spots are typically much thinner than the thickness claimed by the product. So, for example, some textured 6 mil nitrile gloves are only 4 mil in their thin spot valleys. This variance is important to consider when an application demands puncture resistance, tensile strength, chemical permeation and overall durability.

Finally, texturing on a glove can result in very misleading claims. Due to the waffle-type ridges and valleys discussed above, it is essential to understand if a glove is claiming on or off the texture. Standards suggest measuring on a smooth, flat surface, but not all manufacturers are required to follow the standards unless the glove is a medical device. The thickness on the texture area can be 50 percent thicker, for example, than the smooth area right next to the texture. Correspondingly, thinner valleys can also be 50 percent thinner, for instance, than the smooth surface right next to the texture. So it is possible to have a glove claimed to be 8 mil measured on the texture area, with a 6 mil smooth surface and a 4 mil thinnest spot. In some applications, this 8 mil claimed glove would only perform as a 4 mil glove.

Another important note about claims: many medical glove manufacturers claim thickness at the fingertip. Many industrial glove manufacturers claim thickness at the palm. Gloves, such as nitrile and natural latex gloves, are made so that the fingertips are always significantly thicker than the palm, which is considerably thicker than the cuff of the glove. It is crucial to understand what the glove manufacturer is claiming when considering the glove for this application. There could exist a scenario comparing glove specifications on thickness, but the ones with thicker claims are much thinner than the glove with thinner claims.

Summary

Grip is a key performance property for gloves. Multiple factors affect grip, including the materials used in manufacturing, the manufacturing process and texture. Different textures have different properties. When comparing textured gloves, it's essential to ensure that equivalent measures are used. For example, some manufacturers publish thickness based on a glove's fingertip, while others publish thickness based on a glove's palm. Be sure to understand if the reported thickness is based upon the texture or flat/non-textured portion of the glove.

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