Latex gloves have been the first choice
for cleanroom gloves. Concerns about allergic reactions have allowed nitrile to
capture a share of the market. latex is described as the gold standard for
durability. latex falls short in static dissipation. Natural rubber sheds its
outer layer as it becomes worn. As it ages, it continues to decay and flake.
Latex comes in hand-specific textured versions.
Vinyl, which is in second place, is not as
durable or as good a barrier as latex. Oak Technical invented the original vinyl
glove in the late 1950s. Vinyl is inert and does not shed many particles. Vinyl
also has a low transfer characteristic; therefore, glove materials are not
transferred onto the product. No powder is used in making vinyl gloves because
they strip from the mold on which they are formed in a different manner than
latex gloves. Because vinyl is a synthetic, its manufacturing process is cleaner
than latex. Vinyl is abrasion and acid resistant, non-allergenic and has some
anti-static properties. Fingernails may puncture vinyl gloves. It is mostly
suited to a dry environment. Vinyl is a few cents cheaper than latex. Some
manufacturers take vinyl to contract manufacturers for additional cleaning and
packaging. Vinyl's biggest drawback is loose fit. Vinyl is primarily sold in an
ambidextrous smooth finish.
Nitrile is more durable than vinyl but is
an inelastic polymer which is more difficult to form into the thin disposable
glove needed. Newer generations of nitrile gloves are overcoming some of the
disadvantages seen in the earlier gloves. Nitrile resists chemical splash better
than latex and is naturally static dissipative. it is three times more puncture
resistant than latex or vinyl.
There are other glove materials in use but
in much smaller quantity. urethane has been used. Polygenex developed a glove
with a 1.2 to 3 mil thickness for use with implantable medical devices. Urethane
has also been used as a coating for woven gloves of some other material. APSI
offers heat resistant reusable gloves made of lycra. The urethane superbonded
palm withstands temperature of 350°. The gloves are reusable with no breakdown
after 20 washes. They are suitable for Class 10 use. There are four styles. All
have the Lycra back and Lycra palm.
Two sets of gloves are required in many
cases. A donning glove may be put on before garments are donned. later, a second
glove is put on just before the worker enters the cleanroom. Barefoot has come
out with a new double glove which is put on before gowning and the outer glove
is removed before the worker enters the cleanroom
Glove liners are worn in some situations
for worker comfort and to prevent allergic reactions. Berkshire offers a
continuous-filament knitted polyester glove liner designed to be worn under
latex, PVC or outer glove to absorb moisture during periods of extended wear.
The half-fingered design helps minimize bacterial growth, thereby reducing skin
irritation. The glove liner also makes it easier to remove an outer glove. This
liner is seamless and can be laundered and used up to 20 times.
Direct handling is prohibited on submicron
fab lines but is still done in thin film disk manufacturing. The disk drive
industry is concerned with trace level contaminants which may cause corrosion.
Washed latex gloves are used in the
pharmaceutical industry. Grip is of concern in the medical devices industry. A
slippery glove leads to wasted time. Glove powders are not acceptable in this
industry because they may wind up in a wound and lead to infection.
PVC gloves contain NVRs (non volatile
residues) which are a problem in semiconductor, disk drive, aerospace and
optical industries.
Gloves that give the worker greater
tactile sensation lead to increased productivity. Difficulty in handling
products cause reduced productivity. The weight of a glove influences its
durability. Some may last only hours.