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Resource Guide
Chemical Impact on Rubber Rollers
Roller Maintenance Guide
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Chemical Impact On Rubber Rollers
When determining the proper wash for a customer to use on
our rollers or when
evaluating a wash currently being used by a customer, the
first place to look is at
the Material Safety Data Sheet. This will break down the
major components of the
wash in the following categories:
Aliphatic Hydrocarbons
Aromatic Hydrocarbons
Chlorinated Hydrocarbons
Glycols
Alcohols
All hydrocarbons are petroleum based and nearly all
hydrocarbons are VOCs
(Volatile Organic Compounds) which tend to be toxic.
Aliphatic Hydrocarbons are the least harmful to rubber.
Most offset inks, mineral
spirits, naptha, etc. are aliphatic hydrocarbons.
Although these are less harmful to
rubber than the other hydrocarbons, prolonged usage will
cause chemical abrasion
such as shrinkage, premature hardening and ozone
degredation. Therefore, as you
may surmise, printing inks, specifically high solvent
based inks, cause most of the
damage to rollers. Proper cleaning with good solvents
will help to reduce the
impact of the ink. Improper cleaning with bad solvents
will further aggravate the
problem.
Aromatic Hydrocarbons are more harmful to rubber as these
are primarily used as
quick drying cleansing chemicals. These hydrocarbons
consist primarily of toluene
and xylene. These chemicals will attack the oils used to
soften rubber, specifically
the DOP and vegetable oils used in todays compounds.
Chlorinated Hydrocarbons are nasty chemicals. They are
excellent cleaning
solvents, but are very harsh and are likely to be
completely outlawed in the very
near future. They consist primarily of methylene chloride
and
1,1,1-Trichloroethylene. Any solvent that uses these
should be avoided.
Glycols and Alcohols are used primarily in fountain
solutions although the are found
in varying degrees in cleaning solvents. These chemicals
tend to swell rubber on
impact (specifically glycols) which can cause problems
for those shops that clean
on the run. (eg. web presses that clean on the fly and
small sheet-fed shops) They
also tend to dry out the rubber thereby affecting the
hardness of the rubber.
Recommendations:
In order for a consumer to prolong the life of their
rollers it is imperative that they
be educated on what they are actually buying. The MSDS
along with some
chemistry basis as outlined above, and better cleaning
procedures will go a long
way to improving the life of any set of rollers. Although
it is difficult for a GPR
representative to recommend one wash over another, we can
go so far as to
suggest that when selecting a wash, choose one that has
no chlorinated
hydrocarbons and have a higher percentage of aliphatics
than aromatics. For
example, in the Varn family of chemicals we recommend
Varn VWM or Ecoclean
over Varn V-120 or V-253. V-120 has approximately 70%
aromatic to 30%
alphatic hydrocarbons. Ecoclean 35 has approximately 30%
aromatic to 70%
aliphatic hydrocarbons. V-253 is more similar to V-120,
VWM nearer to Ecoclean.
It should be noted that all reputable solvent companies
have similar solvents and
therefore if a customer is using Prisco, for example,
there is a Prisco product with
the characteristics outlined above.
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