Nitrile Latex Glove - Getting Your Product Color & Appearance Right
Disposable gloves are generally made from synthetic elastomeric material like nitrile and natural rubber latex. The recent Covid-19 pandemic has created a surge in world demand for disposable gloves. They are indispensable as it provides the first layer of protection to the healthcare frontline workers against Covid-19 infection.
Quality perception is often associated with consistency hence making color quality control an integral part of gloves manufacturing process. Other critical visual appearance attributes like opacity and gloss are equally important to control.
How Color is Quantify?
The measurement of color is known as colorimetry. Just like weight and distance measurement using SI system, color can be expressed numerically. CIE 1976 L*a*b* color space (also referred to as CIELAB) is one of the most popular color spaces for measuring object colors. It was defined by CIE in 1976 for color communication and is widely adopted today in many industries for color control and management.
In the L*a*b* color space, L* indicates lightness and a* and b* are chromaticity coordinates. a* and b* are color directions: +a* is the red axis, -a’ is the green axis, +b* is the yellow axis and -b* is the blue axis.
What is Opacity?
Opacity index is a numerical value to describe a sample’s level of translucency. The opacity of disposable gloves can be determined by using color measurement instrument with a technique called contrast ratio. The luminous reflectance (Yod) of glove sample backed by a black background divided by the luminous reflectance (Yow) of the same sample backed by a white background is taken as an index of opacity. Generally, white and black tiles or Leneta contrast card are commonly used as the backing material.
Contrast Ratio/Opacity = (Yod/Yow) x 100
If a glove is completely opaque, its opacity is 100. The more transparent the glove, the smaller the opacity.
How Gloss is Measured?
Gloss is determined by projecting a beam of light at a fixed intensity and angle onto a surface and measuring the amount of reflected light at an equal but opposite angle. Measurement angle refers to the angle between the incident and reflected light.
Glossiness provides a visual cue on the glove’s texture.
In glove production, a glossy glove surface is usually not desired. Glossy gloves often give the user the impression that the glove is slippery, and will result in slipping of items held by a gloved hand, particularly in applications where liquid contact is involved. Highly glossy gloves also result in gloves ‘sticking’ to each other making glove extraction from box difficult.
The glossiness of glove is reported in gloss units (GU). To measure gloss, the correct geometry must be used. The angle is selected based on the anticipated gloss range, as shown in the following table.
If measurement exceeds 70° GU, change test setup to 20°
10° ~ 70° GU
If measurement is less than 10° GU, change test setup to 85°
For glove application, 60o or 85o angle is commonly used.
What Measurement Solutions Can Konica Minolta Offer?
To ensure the color and appearance of gloves remain consistent batch-to-batch, manufacturers are shifting from visual assessment to using color instrumentation. Konica Minolta’s next generation of portable Spectrophotometer CM-26dG enables color, opacity and gloss measurement all in one instrument.
Spectrophotometer CM-26dG is a Close Tolerance (CT) grade instruments developed for digital color data management. With tight inter-instrument agreement (IIA) and high repeatability, it is ideal for evaluating the color and gloss simultaneously for gloves application. Furthermore, it has a viewfinder brightly illuminates the measurement point with an LED that makes it even easier and more precise to identify the measurement area. This improves work efficiency, especially when measuring a large number of glove samples.
Contact us for a free consultation with our application specialists and let us assist you on your color and appearance measurement needs.