Note: Descriptions are shown in the official language in which they were submitted.
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V-732
COMPOSITION AND PROCESS FOR ENHANCED DRAINAGE OF RESIDUAL
AQUEOUS RINSE ON THE EXTERNAL SURFACES OF PLASTIC PARTS
FIELD OF THE INVENTION
The present invention relates to compositions and processes
for improved drainage of plastic parts. Aqueous solutions of poly-
ethoxylated and ethoxylated straight chain alcohols are effective at
enhancing the drainage of residual rinse water from the surfaces of
plastic parts.
BACKGROUND OF THE INVENTION
Plastic is painted for both cosmetic and functional reasons.
These reasons include protection against weathering and fadin~,
shielding electronic parts from electromagnetic and radio frequency
interferences and achieving a smooth finish.
Most plastics are paintable with the appropriate choice of
paint. However, some plastics will not accept paint (poor "wet-out"
or adhesion~ regardless of the cleanliness of their surfaces.
Examples of plastics that are paintable and used in the automotive
industry include polycarbonate/polybutylene terephthalate, poly-
phenylene oxide/nylon 66, polyphenylene oxide/polybutylene
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terephthalate, polyether-polyester copolymer/polybutylene tereph-
thalate, polycarbonate (both unfilled and glass filled), polypheny-
leneoxide (both unfilled and filled) and a resin/glass material.
In the automot;ve industry, the formed plastic parts
(fascia) used are often painted. This is to provide a smooth,
oftentimes metal-like finish. The paint covers molding and other
substrate imperfections. Decorative effects such as mirror
finishes, texturing and color match of differently processed parts
are also achieved by painting.
Most plastics need to be cleaned before painting them.
The most common contaminants that must be removed before painting
are mold release agents, shop soil, material handling soil,
machining soils, fingerprints and plastic sanding dust. These
contaminants are removed by chemical means such as detergents.
The process of cleaning plastic parts generally entails a
wash stage, a rinse stage and a final rinse stage with deionized
water. The plastic part can be either spray washed or immersed in
the detergent. The most common processes are either an acidic
detergent wash stage followed by multiple rinse stages, or an alka-
line detergent stage, followed by a rinse stage, an acidic deter-
gent wash stage, and multiple rinse stages. One process, for
example, employs in stage 1 an alkaline wash, followed by a tap
water rinse in stage 2. Stage 3 is an acidic wash with a tap water
rinse in stage 4. Stages 5 and 6 can then be deionized water
rinses.
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When the plastic part is to be painted the cleaning oper-
ation is performed in a production line with the freshly cleaned
part sequentially conveyed into the paint booth. Problems can
occur however, when the freshly cleaned part is not fully dry.
This can lead to "spotting" when painted and will result in an
imperfect paint jobO This will require stripping of the part
and/or an additional painting procedure.
Further, when a bead of water dries on the plastic surface,
ionic salts such as Cl, Ca, Mg and K will remain on the surface of
the plastic. After the plastic has been painted, there will be a
visual defect there. Exposure to humidity can lead to increased
water sensitivity which can lead to blistering of the paint.
Adhesion problems could also possibly result.
Removing the aqueous rinse water from the surface of the
plastic requires a drainage enhancing solution which will effec-
tively aid in drying the plastic part to be painted. The present
inventors have discovered an aqueous solution which will aid in
reducing spotting on the external surface of plastic parts.
SUMMARY OF THE INVENTION
The present invention provides for compositions and
processes for enhancing the drainage of residual aqueous rinse
from the external surfaces of plastic parts comprising a poly-
ethoxy1ated straight chain alcohol and an oxyethylated straight
chain alcohol.
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The present invention effectively reduces the amount of
water on the external surfaces of plastic parts prior to their
being painted. Any water left on the surface of the plastic can
lead to spots or imperfections in the final paint finish. This
invention is particularly effective at aiding in the drainage of an
aqueous rinse from the external surfaces of virgin and rework
plastic used in the automotive industry.
DESCRIPTION OF THE RELATED ART
United States Patent 4,560,493, Scharf et al., December
I985, discloses a composition and method for reducing the liquid
residue remaining on a metal surface consisting of octane-1-phos-
phonic acid or water soluble salt thereof.
United States Patent 3,082,172, Temple et al., March 1963,
discloses a polyoxyalkylene glycol mixture which is useful as a
rinse additive composition in machine dishwashing. The composition
comprises a conventional rinse additive formulation, organic poly-
ethenoxy nonionic surface active agent, and a polyoxyalkylene
glycol mixture consisting of alternating hydrophobic and hydro-
philic polyoxyalkylene chains.
BASF/Wyandotte Technical Bulletin, "The Wonderful World of
Pluronic Polyols'l, United States Library of Congress No. 70-150738
(1971), discloses various uses for ethylene oxide/propylene oxide
block copolymers.
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BASF Technical Bulletin, "Performance Chemicals for Rinse
Aid Formulations", discloses various rinse aid components such as
surfactants and hydrotropes.
United States Patent 3,563,901, Crotty, February 1941,
teaches a rinse aid composition for use in mechanical dishwashers.
The composition consists of an alkali metal or ammonium salt of an
alcohol sulfate and a poly(oxyalkylene) condensate surfactant
possessing an active hydrogen containing organic precursor.
United States Patent 4,806,263, Leathers et al., February
198g, teaches an aqueous based, non-film forming cleaning com-
position for wood, metal and plastic surfaces. The multi-com-
ponent system comprises a fungicide, an algicide, a detergent,
a thickener, and an oxidizing agent in an aqueous solution.
Primarily alcohol ethoxylates and ethoxylated alkyl phenols are the
preferred detergents in this composition.
United States 3,625,901, Rue et al., December 1971, teaches
a composition used as a rinse aid in mechanical dishwashers. The
composition consists of a mixture of a condensation product of
ethylene oxide with a distillate fraction of tall oil and a block
condensation product of ethylene oxide with a distillate fraction
of tall oil.
United States 4,624,713, Morganson et al., November 198~,
teaches methods of warewashing which comprise releasing in the
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rinse cycle a rinse aid. The solid rinse aid consists of urea, a
polyethylene oxide-polypropylene oxide block copolymer, and water.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides for compositions and
processes for enhancing the drainage of residual aqueous rinse
from the external surfaces of plastic parts comprising a modified
polyethoxylated straight-chain alcohol and a modified oxyethylated
straight-chain alcohol.
The preferred materials in accordance with this invention
include combinations of modified polyethoxylated and oxyethylated
straight-chain alcohols. These are available from Betz
Laboratories as HPC 10.
The modified polyethoxylated straight-chain alcohol and
modified oxyethylated straight-chain alcohol are preferably
blended together in an aqueous medium, such as deionized water, to
form a concentrate. The modified polyethoxylated straight-chain
alcohol can range from about 1Z.5% to about 92.6% by weight of the
composition. The modified oxyethylated straight-chain alcohol can
range by weight from about 1% to about 7.4% of the composition.
A preferred concentrate is 4% modified oxyethylated straight-chain
alcohol, 46% deionized water and 50% modified polyethoxylated
straight-chain alcohol.
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The preferred means of applying the rinse aid is by
spraying or immersing the plastic piece to be processed in the
rinse aid. The rinse aid may also be applied to the plastic piece
by spraying the rinse aid onto the plastic piece. The rinse aid
may have a concentration of about 0.01% to about 25% with a 0.01%
to about 1.0% concentration of rinse aid being preferred.
The invention will now be further described with reference
to a number of specific examples which are to be regarded so1ely
as illustrative, and not as restricting the scope of the invention.
I0 EXAMPLES
Automotive grade plastic parts 3" x 4" in size, trade name
Xenoy, available from General Electric, were cleaned in the
following sequence:
Stage Treatment Step
1 3% Betz KleenR 132, 1 min. spray, 140F
2 Tap rinse, 45 seconds
3 2% PermatreatR 302, 30 sec. spray 135F
4 Tap rinse, 30 seconds
Deionized water rinse, 30 seconds
Betz KleenR 132 and PermatreatR 302 are trademarks of
Betz Laboratories, Inc.
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To evaluate the efficacy of the inventive concentrate as a
rinse aid, dilute solutions of Betz HPC 10 were used in place of the
deionized water rinse in Stage 5. Evaluations were based on the
weight of water retained on the 3" x 4" plastic surface and visual
observation of surface wetting. The surface wetting is reported as
percent water break free. A 100% water break free is wet with a
continuous film of water. A 0% water break free surface has beads
of water on its surface. The results of this testing is reported in
Table I.
TABLE I
Rinse Aid Water Weight Retained % Water Break Free
Deionized water 1.0460 0
0.1% Betz HPC 10 0.2486 100
From these observations, it can be seen that the inventive
treatment is effective at enhancing the drainage of rinse water
from the surfaces of plastic parts. This is evidenced by the
reduced weight of water retained on the plastic surface and the
100% water break free observation.
While this invention has been described with respect to
particular embodiments thereof, it is apparent that numerous other
furms and modifications will be obvious to those skilled in the
art. The appended claims generally should be construed to cover
all such obvious forms and modifications which are within the true
spirit and scope of the present invention.
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