U.S. patent application number 11/169049 was filed with the patent office on 2006-01-05 for dry film lubricant.
This patent application is currently assigned to Henkel Kommanditgesellschaft auf Aktien (Henkel KGaA). Invention is credited to Jasdeep Sohi.
Application Number | 20060003901 11/169049 |
Document ID | / |
Family ID | 35169973 |
Filed Date | 2006-01-05 |
United States Patent
Application |
20060003901 |
Kind Code |
A1 |
Sohi; Jasdeep |
January 5, 2006 |
Dry film lubricant
Abstract
The present invention relates to compositions and methods
employing a first copolymer that is an acrylic copolymer or
styrene/acrylic copolymer having a weight average molecular weight
(Mw) of about 8,000 to about 14,000; a second copolymer that is an
acrylic copolymer having a Mw of about 90,000 to about 130,000; a
wax emulsion or dispersion, and a particulate additive. Optionally,
the composition further comprises at least one of a rheological
additive, ammonium hydroxide or a defoaming compound.
Inventors: |
Sohi; Jasdeep; (Shelby
Township, MI) |
Correspondence
Address: |
WOODCOCK WASHBURN LLP
ONE LIBERTY PLACE, 46TH FLOOR
PHILADELPHIA
PA
19103
US
|
Assignee: |
Henkel Kommanditgesellschaft auf
Aktien (Henkel KGaA)
Duesseldorf
DE
|
Family ID: |
35169973 |
Appl. No.: |
11/169049 |
Filed: |
June 28, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60585058 |
Jul 2, 2004 |
|
|
|
Current U.S.
Class: |
508/139 ;
106/14.14; 428/357; 508/148; 508/451; 508/469; 508/472;
508/552 |
Current CPC
Class: |
C10M 2207/28 20130101;
C10N 2020/011 20200501; C10M 2203/10 20130101; C10M 2209/103
20130101; C10N 2020/01 20200501; C10N 2040/12 20130101; C10N
2030/10 20130101; C10N 2040/252 20200501; Y10T 428/29 20150115;
C10M 2201/02 20130101; C08K 3/34 20130101; C10N 2030/06 20130101;
C09D 5/008 20130101; C10N 2040/26 20130101; C08L 33/04 20130101;
C10M 105/38 20130101; C10M 2207/401 20130101; C10N 2040/255
20200501; C08L 2205/02 20130101; C08L 33/04 20130101; C08L 2666/04
20130101 |
Class at
Publication: |
508/139 ;
508/148; 508/451; 508/469; 508/472; 508/552; 106/014.14;
428/357 |
International
Class: |
C10M 107/28 20060101
C10M107/28 |
Claims
1. A composition, comprising: a first copolymer that is an acrylic
copolymer or styrene/acrylic copolymer having a weight average
molecular weight (Mw) of about 8,000 to about 14,000; a second
copolymer that is an acrylic copolymer having a Mw of about 90,000
to about 130,000; water; a wax emulsion and/or wax dispersion; and
a particulate additive.
2. The composition of claim 1, wherein said first copolymer is
present in a range from about 10 to about 23 percent by weight of
the composition.
3. The composition of claim 1, wherein said second copolymer is
present in a range from about 30 to about 70 percent by weight of
the composition.
4. The composition of claim 1, wherein said water is present in a
range from about 5 to about 30 percent by weight of the
composition.
5. The composition of claim 1 additionally comprising a rheological
additive.
6. The composition of claim 1, wherein said theological additive is
modified urea in N-methyl pyrrolidine and is present in a range
from about 0.1 to about 1 percent by weight of the composition.
7. The composition of claim 1 comprising a wax emulsion that
comprises paraffin and polyethylene.
8. The composition of claim 7, wherein said wax emulsion is present
in a range from about 3 to about 18 percent by weight of the
composition.
9. The composition of claim 1, wherein said particulate additive is
a silicate.
10. The composition of claim 1, wherein said particulate additive
is a silicate including at least one of Al or Mg.
11. The composition of claim 1, wherein said particulate additive
is talc.
12. The composition of claim 11, wherein said talc is present in a
range from about 0.01 to about 4 percent by weight of the
composition.
13. A coating comprising the composition of claim 1.
14. A substrate contacted by the composition of claim 1, wherein
the substrate is stainless steel, galvanized steel, hot dipped
galvanized steel, electro galvanized steel, galvanneal alloy, alloy
steel comprising 55% aluminum, 43.5% zinc, and 1.5% silicon, cold
rolled steel, hot rolled steel, or aluminum.
15. A method for reducing blocking between substrates, comprising
contacting said substrates with the composition of claim 1.
16. The method of claim 15 wherein the coating is dried using
surface temperatures lower than about 200.degree. F., and as low as
about 170.degree. F.
17. A composition, comprising: a first copolymer that is an acrylic
copolymer or styrene/acrylic copolymer having a weight average
molecular weight (Mw) of about 8,000 to about 14,000; a second
copolymer that is an acrylic copolymer having a Mw of about 90,000
to about 130,000; water; a wax emulsion; a particulate additive;
and a viscosity builder.
18. A composition, comprising: a styrene/acrylic copolymer
colloidal dispersion; a thermoplastic acrylic copolymer colloidal
dispersion; water; a urea-containing rheological additive; a wax
emulsion; a silicate including at least one of Mg or Al; and
ammonium hydroxide.
19. The composition of claim 18, further comprising a defoaming
compound.
20. The composition of claim 18, wherein said silicate is talc.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims benefit to U.S. Provisional
Application Ser. No. 60/585,058, filed Jul. 2, 2004, which is
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The invention relates generally to dry film lubricants,
coatings, coated substrates, and methods related thereto.
BACKGROUND OF THE INVENTION
[0003] Metal plates or other like materials are often used to form
parts, for various uses, including automotive, appliance, and
general industrial uses, via stamping. Before stamping, the plates,
or more broadly, substrates, are typically stored. During storage,
the substrates may be exposed to conditions that can cause
corrosion and/or blocking of the parts. Blocking is a surface
phenomenon where two substrates adhere to each other, usually due
to heat or pressure.
[0004] To prevent corrosion and blocking, it is known by those of
skill in the art to apply a coating to the substrate prior to
stamping. For example, mill oils, pre-lubes, drawing compounds, and
dry film lubricants are valuable for preventing corrosion or
reducing blocking between substrates, such as stainless steel,
galvanized steel, including hot dipped galvanized steel and electro
galvanized steel, galvanneal alloy, GALVALUME.RTM. alloy (55%
aluminum, 43.5% zinc, 1.5% silicon alloy steel), cold rolled steel,
hot rolled steel, or aluminum.
[0005] However, while it is a goal to minimize corrosion and
blocking between substrates while providing a uniform coating, the
coatings must be readily removable before or during subsequent
steps, such as stamping.
[0006] U.S. Pat. No. 6,187,849 discloses a temporary lubricant
coating which has a wax, an acid-neutralized polymer that is
derived from polymerization of a ethylenically unsaturated monomer
having an acid functionality and at least one different
polymerizable, ethylenically unsaturated monomer, and certain
amines.
[0007] Existing approaches to temporary lubricants have
deficiencies. Some compositions provide adequate corrosion
protection but can cause blocking. Other compositions provide a
smooth coating and good scratch resistance but still allow
corrosion. Thus, there is a need in the art for a dry film
lubricant with improved anti-blocking and anti-corrosion
properties, but which is still readily removable, such as by
application of an alkaline cleaner.
SUMMARY OF THE INVENTION
[0008] The instant invention provides a product that provides good
anti-blocking and good anti-corrosion properties while being able
to be removed with an alkaline cleaner. In one embodiment, the
present invention is directed to compositions and methods employing
an acrylic copolymer or styrene/acrylic copolymer having a weight
average molecular weight (Mw) of about 8,000 to about 14,000, a
thermoplastic acrylic copolymer having a Mw of about 90,000 to
about 130,000, water, a wax emulsion or wax dispersion, and a
particulate additive. In some embodiments, a rheological additive
can be used. Optionally, the composition further comprises at least
one of ammonium hydroxide or a defoaming compound.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0009] According to one embodiment, the present invention provides
a composition, comprising a first copolymer that is an acrylic
copolymer or styrene/acrylic copolymer having a weight average
molecular weight (Mw) of about 8,000 to about 14,000, a second
copolymer that is an acrylic copolymer having a Mw of about 90,000
to about 130,000, water, a wax emulsion or dispersion, and a
particulate additive.
[0010] In one embodiment, the first copolymer has an acid number
(AN) of at least 110. In some embodiments, the acid number is
between about 160 and about 220. In one embodiment, AN is about
200.
[0011] In certain embodiments, the second copolymer has an acid
number of about 90 to about 130. In one preferred embodiment, the
acid number is about 116.
[0012] It is understood that throughout this application, wherever
a range is cited, it includes all combinations and subcombinations
of ranges and specific values therein. The present invention also
contemplates that acid numbers below or above the ranges cited for
the first and second copolymers may be useful, provided that they
produce a composition that remains relatively easy to remove with
alkaline cleaner and has suitable anti-corrosion properties.
[0013] In some embodiments, the first copolymer has a glass
transition temperature (Tg) of about 60 to about 80.degree. C. In
one embodiment, the Tg of the first copolymer is about 70.degree.
C. In certain embodiments, the Tg of the second copolymer is about
35 to about 70.degree. C. In one preferred embodiment the Tg of the
second copolymer is about 47.degree. C.
[0014] In certain of these embodiments, the first copolymer is a
styrene/acrylic copolymer. In some embodiments, the first copolymer
has a low Volatile Organic Content (VOC). In one embodiment of the
invention, the styrene/acrylic copolymer is a solid with a
molecular weight of about 11,000 and an AN of about 200.
[0015] Styrene/acrylic polymer compositions are commercially
available. Certain of these are copolymers that are commercially
available from Noveon, Inc., Cleveland, Ohio, USA, under the trade
name "CARBOSET.RTM. GA." One such product is CARBOSET.RTM. GA-2299
copolymer which is a styrenic/acrylic copolymer having the
following characteristics ascertained from publicly available
sources: Total Solids: 99%; Tg: 70.degree. C.; AN: 200; Molecular
Weight (MW): 11000; and VOC: <0.1%.
[0016] In some embodiments of the invention, the styrene/acrylic
copolymer is a colloidal dispersion. In certain embodiments, the
styrene/acrylic copolymer colloidal dispersion has total solids of
about 22% to about 35%. Preferably, the total solids are about
27.5% to about 30%. Some styrene/acrylic copolymer colloidal
dispersions have a Brookfield viscosity of about 1000 cps to about
4000 cps. Certain styrene/acrylic copolymer colloidal dispersions
are in ammonia water (ammonium hydroxide). In some embodiments, the
styrene/acrylic copolymer colloidal dispersion has a pH of about
8.4 to about 9.2.
[0017] In one embodiment, the styrene/acrylic copolymer colloidal
dispersion is present in a range from about 2 to about 30 percent
by weight of the composition. In other embodiments, the
styrene/acrylic copolymer colloidal dispersion is preferably
present in an amount of about 10 to about 23 percent by weight of
the composition. In one preferred embodiment, the styrene/acrylic
copolymer colloidal dispersion is about 16.7 percent by weight of
the composition.
[0018] In one embodiment, the styrene/acrylic copolymer colloidal
dispersion is a product commercially available from Noveon, Inc.,
Cleveland, Ohio, USA, under the trade name "CARBOSET.RTM. GA 2300."
CARBOSET.RTM. GA-2300 is a high solids solution of a low molecular
weight styrene/acrylic copolymer (CARBOSET.RTM. GA-2299) and
ammonia water. CARBOSET.RTM. GA-2300 styrene/acrylic copolymer
colloidal dispersion has the following characteristics ascertained
from publicly available sources: Weight per Gallon: 8.9 lbs.; AN:
about 190; VOC: <0.1%, along with excellent freeze/thaw
stability, heat stability, and mechanical stability.
[0019] The second copolymer comprises an acrylic monomer and at
least one additional monomer. Suitable acrylic monomers include
methacrylic acid, acrylic acid, and their ester analogs. Suitable
esters include C.sub.1-C.sub.12 alkyl esters. In some embodiments,
the methyl, ethyl, butyl, or 2-ethylhexyl esters are preferred.
[0020] Suitable monomers for the "at least one additional monomer"
useful in making acrylic compositions are well known to those
skilled in the art. The additional monomer may be another of
methacrylic acid, acrylic acid, or their ester analogs. Other
suitable monomers include ethylenically unsaturated materials, such
as styrene, vinyl toluene, and nitrites such as acrylonitrile and
methyacrylonitrile, and vinyl halides. Yet other suitable monomers
include crotonic acid, itaconic acid, and maleic acid.
[0021] In some embodiments, the second copolymer that is an acrylic
copolymer has a low VOC. In certain embodiments, the acrylic
copolymer has an AN greater than about 80. In some embodiments, the
AN is about 110 to about 122. In one embodiment, the second
copolymer has an AN of about 116. In some preferred embodiments,
the acrylic copolymer has a Tg of about 47.degree. C.
[0022] In one embodiment, the second copolymer is partially
neutralized with a base. In certain embodiments, that base is
preferably a volatile base such as ammonia, NH.sub.4OH, or a
primary or secondary amine.
[0023] In certain embodiments, the second copolymer is an emulsion
in water. In one embodiment, the acrylic copolymer is a colloidal
dispersion. Some copolymer colloidal dispersions have a molecular
weight (Mw) of about 8,600 and an AN of about 116. In one
embodiment, the acrylic copolymer colloidal dispersion has total
solids of about 26% to about 28%. In some embodiments, the total
solids is preferably about 27%.
[0024] In one embodiment, the second copolymer is an acrylic
copolymer colloidal dispersion that has a Brookfield viscosity of
about 10 cps to about 200 cps. In some embodiments, the
thermoplastic acrylic copolymer colloidal dispersion has a pH of
about 7.0 to about 8.0. In some embodiments, the pH is about
7.6.
[0025] Some embodiments of the invention have the second copolymer
as an acrylic copolymer colloidal dispersion present in a range
from about 30 to about 70 percent by weight of the composition. In
certain preferred embodiments, the acrylic copolymer colloidal
dispersion is about 51.8 percent by weight of the composition.
[0026] In one embodiment, the second copolymer is an acrylic
copolymer colloidal dispersion that is a product commercially
available from Noveon, Inc., Cleveland, Ohio, USA, under the trade
name "CARBOSET.RTM.." In one embodiment, the product is preferably
CARBOSET.RTM. 560 acrylic colloidal dispersion. CARBOSET.RTM. 560
acrylic colloidal dispersion is a thermoplastic acrylic copolymer
having the following characteristics ascertained from publicly
available sources: Total Solids (%): 26.0 to 28.0, Tg : 47.degree.
C., AN: 116, Total Solids by Volume: 24.5%, pH 7.0 to 8.0,
Brookfield Viscosity, cps 10 to 200, Vapor Pressure (20 C.): 2.34
kPa, % Volatile by weight: 73, VOC: Pounds per Gallon: 0.16/Grams
per Liter: 20, Boiling Point (C): 100.degree. C., Weight per
Gallon: 8.6, Density: 1.0 to 1.2 kg/m.sup.3, MFFT: 17.degree. C.,
and is miscible in water. While not wanting to be bound by theory,
it is believed that the surface amines provide dispersion stability
as water is added, and the polymer becomes more insoluble as the
water content increases. The polymer contains carboxylic acid
functional groups.
[0027] Water may be added even when the components are in aqueous
solution. Such added water (exclusive of water in the other
components), if added, may be present in an amount up to about 30
percent by weight of the composition. In some embodiments, the
added water is present in a range from about 5 to about 30 percent
by weight of the composition. In one preferred embodiment, the
water is about 18.3 percent by weight of the composition. In
contrast, the total water present, from all sources in the
composition may range from about 50 to about 80 percent by weight
of the composition, preferably from about 70 to about 75 percent by
weight of the composition.
[0028] In one preferred embodiment, the water is deionized
water.
[0029] The Theological additive can be selected from a number of
conventional compositions well known to those skilled in the art.
Such additives are also known in the trade as anti-settling agents.
In one preferred embodiment, the rheological additive is a liquid
rheological additive for aqueous coatings.
[0030] While not wanting to be bound by theory, it is believed that
the rheological additive provides an anti-settling benefit. Any
amount of this additive which prevents settling (i.e., maintains
stability) but without rendering the composition too viscous to
apply is acceptable.
[0031] In one embodiment, the rheological additive is present in a
range from about 0.1 to about 1 percent by weight of the
composition. In certain preferred embodiments, the rheological
additive is about 0.5 percent by weight of the composition.
[0032] In certain preferred embodiments, the rheological additive
is modified urea in N-methyl pyrrolidone, and is commercially
available from BYK-Chemie USA Inc., Wallingford, Conn., USA, under
the trade name "BYK.RTM. 420." BYK.RTM.-420 is a liquid rheological
additive, wherein after incorporation, a three-dimensional network
is believed to develop. The resulting thixotropic flow behavior
prevents settling and improves sag resistance. BYK.RTM.-420
rheological additive has the following characteristics ascertained
from publicly available sources: Weight per Gallon: 9.33 lbs;
Density at 20.degree. C.: 1.12 g/mL.
[0033] Other rheological additives include Crayvallac LA-100
available from Cray Vally and BYK-425 from BYK-Chemie.
[0034] In one preferred embodiment, the wax is in the form of a wax
emulsion. The wax emulsion generally comprises a stable mixture of
wax, emulsifier, and water. Wax comprises natural waxes, including
animal waxes, for example, beeswax and lanolin, vegetable waxes,
for example, carnauba and candellila, and mineral and petroleum
waxes, for example, montan, paraffin, slack, scale, and
microcrystalline, and synthetic wax-like substances, such as
polyethylene, polypropylene, Fischer-Tropsch compounds, and resins
such as ethylene-acrylic acid. In some embodiments, a wax emulsion
comprises particles that are less than one micron (1.mu.) in
size.
[0035] In one embodiment, the wax emulsion is present in a range
from about 3 to about 18 percent by weight of the composition. In
one preferred embodiment, the wax emulsion is about 10.3 percent by
weight of the composition. In some embodiments, the wax has a
melting point in the range of 50 to 160.degree. C. In certain
embodiments, the melting point is from 55 to 110.degree. C. In one
embodiment, the wax emulsion has an melting point (Mp) of about
60.degree. C.
[0036] In one preferred embodiment, the wax emulsion contains
paraffin and polyethylene. One such a wax emulsion is commercially
available from Michelman, Inc., Cincinnati, Ohio, USA, under the
trade name "MICHEM.RTM. EMULSION," and in one embodiment is
preferably MICHEM.RTM. EMULSION 62330. Other wax emulsions include
those sold under the tradenames MICHEM.RTM. Lube and MICHEM.RTM.
Shield from Michelman, Inc. and Aquatec 4111 from Lawter
International.
[0037] Alternatively, a wax dispersion may be used. A wax
dispersion comprises micronized waxes dispersed in water. Any
suitable wax emulsion or dispersion can be used, as long as it
provides sufficient water repellency and formability to the
composition. In some embodiments, the particles of the wax
dispersion are greater than one micron in size.
[0038] In one embodiment, the particulate additive is present in a
range from about 0.01 to about 4 percent by weight of the
composition. In certain preferred embodiments, the particulate
additive is preferably present in an amount of about 2.0 percent by
weight of the composition. The particulate additive is believed to
be desirable for block and corrosion resistance, and greater
amounts can be used, provided there is no negative effect on
stability of the composition.
[0039] In one embodiment, the particulate additive is clay or
silicate. In some compositions, the silicate includes at least one
of Mg or Al. In one embodiment, the particulate additive is a
magnesium silicate.
[0040] In another embodiment, the particulate additive is talc. The
talc may be, for example, hydrous magnesium silicate, and is
commercially available from Reade Advanced Materials, Providence,
R.I., USA. Talc is also known as talc powder, cosmetic talc, French
talc, Montana talc, Texas talc, Vermont talc, industrial talc,
tremolitic talc, steatite talc, fibrous non-tremolite talc, no
asbestos talc, magnesium silicate talc, talcum, French chalk, talc
(Mg.sub.3H.sub.2(SiO.sub.3).sub.4).
[0041] Commercial products include Nytal.RTM. 300, a talc marketed
by Lansco Colors, and reported to have a median diameter of 6.9
microns. Other Nytal.RTM. talcs are reported to have mean diameters
of 4.5, 7.0, 8.7, and 12.6 microns. The Nytal.RTM. talcs are
believed to be a mixture of platy and needle shaped particles.
Another commercial product is Artic Mist.RTM., a platy talc
available from Luzenac America that has a mean diameter of 2.2
microns. Nicron.RTM. 402, available from Luzenac America, is a
platy talc having a mean diameter of 10 microns. Vertal.RTM. 92,
available from Luzenac America, is a larger diameter talc with a
platy structure. The mean diameter of these particles is 17.5
microns.
[0042] In some embodiments, the particulate is a plate shape. In
other embodiments, the particulate is needle shaped. In certain
preferred embodiments, the particulate is a mixture of the two
shapes.
[0043] Some preferred particles have a mean particle size of about
0.5 to about 3 microns. Such preferred particles may have a mean
particle size of about 2 microns. Other particles have a mean
particle size of about 5 to about 25 microns. One example of such
particles has a mean diameter of about 6.9 microns, another has a
mean diameter of about 17 microns. In some preferred embodiments,
it is desirable to have a mixture of the smaller and larger
particles detailed above. Such a mixture has been observed to
provide better resistance to the fingernail scratch test and
anti-blocking characteristics than either type of particle does by
itself.
[0044] According to another embodiment of the present invention,
the composition further comprises a viscosity builder. In one
embodiment, the viscosity builder is a base. The amount of the base
required is that sufficient to neutralize the acid functional
groups on the copolymers, which is readily calculable by one of
skill in the art. One suitable viscosity builder is ammonium
hydroxide. One commercial source of ammonium hydroxide is known by
the product name "Ammonium hydroxide 26 Be" from Univar USA,
Kirkland, Wash., USA 98003. Ammonium hydroxide 26 Be is also known
as "aqua ammonia water," and typically contains between 28% to 30%
ammonia before dilution. Another source of ammonium hydroxide is
Sigma-Aldrich.
[0045] In some embodiments, the ammonium hydroxide is present in a
range from about 0.01 to about 0.8 percent by weight of the
composition. In one preferred embodiment, the ammonium hydroxide is
about 0.4 percent by weight of the composition.
[0046] In an alternative embodiment of the present invention, the
ammonium hydroxide can be replaced with alkali bases or amines, for
example 2-aminomethyl-propanol (AMP), morpholine, dimethyl ethanol
amine (DMEA).
[0047] According to other embodiments of the present invention, the
compositions further comprises a defoaming compound. Many defoamers
are know to those skilled in the art and can be used so long as
their use does not negatively impact other product properties.
Suitable defoaming compounds include compositions that comprise
straight chain petroleum distillates, silica, surfactants, and/or
wax. In one embodiment, the defoaming compound comprises about 80%
to about 90% straight chain petroleum distillates, about 1% to
about 10% silica, about 1% to about 10% surfactants, and about 1%
to about 10% wax.
[0048] One preferred defoaming compound is a product commercially
available under the trade name "HYDRO SPEC DO-101" available from
Henkel Surface Technologies, Madison Heights, Mich., USA, having a
pH 6.5 to 7.5 (of concentrate), viscosity at 25.degree. C.: 800 cps
to 2000 cps, and specific gravity: 0.85 to 0.90. Other oil-based
defoamers include those sold under the tradename Hi-Mar by the
Thornley Company and FOAMASTER SA-3 available from Fritz Chem
Corporation.
[0049] One or more coalescing agents may be added to the instant
composition. Suitable agents include low molecular weight
ethoxylated alcohol and propylene glycol esters of fatty acids. One
preferred agent is an aromatic alkoxylated ester such as, for
example, an ethoxylated benzyl alcohol. Suitable commercial
products include Archer RC.RTM., CAS # 515152-38-2, from ADM. This
product is derived from sunflower or corn oil fatty acids with
propylene glycol. Another agent is Genapol BA 040, a benzyl alcohol
ethoxylate, CAS # 26403-74-7, available from Clariant. In one
preferred embodiment, a mixture of ethoxylated alcohol and
propylene glycol esters of fatty acids is used.
[0050] In yet another embodiment, the present invention provides a
coating comprising any of the compositions described above where
the compositions having been dried in place to remove water and any
other volatiles present. Preferably the composition is applied by
any conventional means known in the art and is then dried. In one
embodiment, the coating does not react with the substrate, nor does
it oxidize, but maintains its original applied characteristics.
[0051] In another embodiment, the composition of the present
invention can be diluted with water to provide any desired coating
weight required for protection under most storage conditions. The
temporary protective coating of the invention may be applied to
metallic substrates by any conventional application means known in
the art such as spraying, brushing, dipping, roll coating, curtain
coating or the like. The coating is typically applied at film
weights of 100 to 600, preferably 150 to 500, and more preferably
200 to 350 milligrams per square foot. Coating weights are
typically in the range from about 150 mg/ft.sup.2 to 300
mg/ft.sup.2.
[0052] Applied temporary protective coatings can be air dried or
force dried. Typically, the applied coatings are forced dried at
temperatures ranging from 50.degree. C. to 250.degree. C.,
preferably from 70.degree. C. to 200.degree. C., and more
preferably from 90.degree. C. to 150.degree. C. In yet another
embodiment, once applied the coating of the present invention can
be dried by achieving surface temperatures less than 200.degree.
F., and in a presently preferred embodiment as low as 170.degree.
F.
[0053] In a preferred embodiment, this coating can be removed by
alkaline cleaning, but is advantageously not water-soluble. Once
removed, the surface is available for further processing. Removal
of the applied coating is effected by contacting the coated
substrate with an aqueous alkaline solution, such as by spraying,
flooding, immersion or the like.
[0054] In still another embodiment, the present invention provides
a substrate contacted by any of the compositions described above.
In one embodiment, the substrate may be stainless steel, galvanized
steel, hot dipped galvanized steel, electro galvanized steel,
galvanneal alloy, GALVALUME.RTM. alloy (55% aluminum, 43.5% zinc,
1.5% silicon alloy steel), cold rolled steel, hot rolled steel, or
aluminum.
[0055] According to yet another embodiment, the present invention
provides a method for preventing corrosion on a substrate,
comprising contacting the substrate with any of the compositions
described above. In another embodiment, the present invention
provides a method for reducing blocking between substrates,
comprising contacting the substrates with any of the compositions
described above.
[0056] The present invention provides, in one embodiment, a
composition, comprising a copolymer comprising at least one of
styrene/acrylic or acrylic, a thermoplastic acrylic copolymer,
water, a rheological additive, a wax emulsion, a particulate
additive, and a viscosity builder.
[0057] In yet another embodiment, the present invention provides a
composition, comprising a styrene/acrylic copolymer colloidal
dispersion, a thermoplastic acrylic copolymer colloidal dispersion,
water, a urea-containing rheological additive, a wax emulsion, a
silicate including at least one of Mg or Al, and ammonium
hydroxide.
[0058] The present invention also provides a composition comprising
CARBOSET GA-2300 copolymer, water, a rheological additive, a
particulate additive, a viscosity builder, a wax emulsion, and
CARBOSET 560 copolymer.
EXAMPLES
Example 1
[0059] A dry film lubricant was prepared having the components
listed in TABLE 1. TABLE-US-00001 TABLE 1 Percentage Component (By
Weight Of Composition) CARBOSET .RTM. GA-2300 polymer 16.7 Talc
(about 10 micron mean diameter) 2.0 Deionized Water 18.3 BYK .RTM.
420 rheological additive 0.5 MICHEM .RTM. EMULSION 62330 wax 10.3
CARBOSET .RTM. 560 polymer 51.8 Ammonium hydroxide 0.4
[0060] While not wishing to be bound to any theory of operation,
the composition functions without the talc and the ammonium
hydroxide, and so these components are optional. The pH of the
composition should be 7 or greater.
Example 2
[0061] The composition from TABLE 1 was characterized using
conventional methods.
Liquid form
[0062] The viscosity of the composition as measured in a #2 Zahn
Cup was 32-34 seconds. A free flowing liquid was observed after
placing the composition in a sealed container at 100.degree. F. for
a predetermined time period, thus showing good storage
stability.
Coated Panels
[0063] Cold rolled steel substrate panels were coated with the
composition from TABLE 1 by using a drawdown bar. The coating
weights, determined via the Weigh Strip Weigh method using
methylethyl ketone (MEK), were 220-260 mg/sqft.
[0064] Water spotting was tested by placing a drop of water on the
coated panel and observing for staining. No staining on coated
panels was observed during the thirty minute water drop test.
[0065] 1T bend tests were performed using ASTM D4145. The test used
a hand-operated die. The panels were then taped with Scotch tape at
the location of the bend, the tape was removed and the bend radii
were wiped with copper sulphate to see if the coating was removed
by the tape. Very light copper sulfate stain was observed after
removal of the tape.
[0066] Reverse Impact Tests were performed as in ASTM D2794. All
the panels were subjected to impact of a ball at 80 inch/pounds.
After impact, the panels were taped at the bend or dent, the tape
was removed and bend radii were then wiped with copper sulfate to
see if the coating was removed by the tape. Very light copper
sulfate stain after taping was observed.
[0067] The composition was cleanable with PCL 75 LC as per TPB
232070 (2% solution of PCL 75 LC in water @ 110.degree. F. for 60
sec). To determine whether there was any residue of the dry
lubricant on the panels, the substrate panels were cleaned, then
rinsed with deionized water and dried. A drop of about 3 wt %
copper sulfate pentahydrate solution was dropped on the panels. A
100% reaction, evidenced by the area of the panel that contacted
the drop turning black within a second of contact, was observed on
all the panels, indicating the panels were fully cleaned and were
water break free.
[0068] The composition performed satisfactorily when formed, as
evidenced by formability testing, such as determining limiting dome
height (LDH) using a MTS Metalform 866 LDH Machine. This test was
performed by contacting the panel with a die to see how far the
surface could deform without disrupting the coating.
[0069] The testing showed that the composition had acceptable
properties for a dry film lubricant, and performed at least as well
in the above tests as a commercially available dry film lubricant
sold under the trade name "CHEMFORM.RTM." available from PPG
Industries, Inc. Pittsburg, Pa., USA. In particular, the
competitive product showed very light copper sulfate stain in the
1T bend test and reverse impact test. The competitive product
showed no staining in the water spotting test.
Example 3
[0070] The composition from TABLE 1 and the comparative dry film
lubricant were each tested in a 24 hour stack test.
[0071] Cold rolled steel substrate panels were coated using either
the composition from TABLE 1 or the comparative dry film lubricant.
Like-coated panels were clipped face to face with paper clips and
placed in a beaker over water, but not sitting in the water. The
beaker was covered with plastic and taped shut, and then placed in
an oven at 100.degree. F. for 24 hours.
[0072] Panels coated with the composition from TABLE 1 showed no
haziness, corrosion, or stickiness.
[0073] Panels coated with the comparative dry film lubricant were
very hard to take apart and showed 80-90% haziness. It is not
desired for the panels to show any corrosion or blocking as it will
be hard to uncoil the coils after sitting in the hot and humid
atmosphere.
Example 4
[0074] The composition from TABLE 1 and the comparative dry film
lubricant were each tested in a Blocking Test using Carver
hydraulic equipment at 5000-6000 psi at 140.degree. F. The object
of the test was to determine and compare blocking (panels sticking
together to form a block as representing coiled) of panels coated
with different coatings.
[0075] For the blocking test, 2''.times.4'' strips are cut from the
panels where both sides were coated with organic passivate. To test
for blocking the Carver hydraulic press used for T-bends was
equipped with constant temperature heating blocks attached to
variants. The variants were adjusted as necessary to maintain a
constant temperature as measured by a VWR dual input J-type
thermocouple. Panels were tested face to face in pairs with three
pairs on the press at any one time. The press was to set to
approximately 5000 lbs for 30 minutes. Pressure was observed to
stay between 5000-6000 lbs during the course of the blocking test.
Panels were tested at different constant temperatures between
110-140.degree. F. After 30 minutes the panels are removed from the
press, allowed to cool and observed for blocking behavior. The
panels passed the blocking test at that temperature if the panels
fell apart easily and there is no sound when separating panels.
[0076] Cold rolled steel substrate panels were coated using either
the composition from TABLE 1 or the comparative dry film lubricant.
Panels coated with the composition from TABLE 1 showed no blocking
at 140.degree. F. Panels coated with the comparative dry film
lubricant showed some blocking at 130.degree. F.
Example 5
[0077] The composition of Example 1 was prepared where the talc
(17.5 micron mean diameter) was replaced with 1% each of the Artic
Mist.RTM. and Nytal 300. In addition, 1% each of the BA040 and
Archer RC were added to the composition.
Example 6
[0078] The composition of Example 5 was tested for performance by a
variety of tests described below. The coating was applied to the
cold rolled steel panels using a drawbar. The results are presented
in Table 2. The column labeled "Performance Criteria" represents
properties desired for use of dry film lubricants in commercial
applications, such as automotive, appliance, and general industrial
uses. TABLE-US-00002 TABLE 2 Perfor- Test mance Test Method Test
Description Criteria Results Coating Coating Weights by Weigh
180-260 220-260 Weights Strip Weigh using MEK as mg/sqft mg/sqft
described in Example 2. PMT Heat Tapes 180- 200.degree. F.
200.degree. F. 30 Minute A drop of water was placed No staining
Pass Water Spot on the substrate which was Test observe for
staining over 30 minutes. 48 Hr The coated panels were No Haziness,
Pass Stack clipped face to face with corrosion Test paper clips and
place in a and beaker with water. The stickiness panels were placed
on plastic blocks so they don't sit in the water. The beaker was
covered with a plastic bag and taped shut. The beaker was placed in
the oven at 100.degree. F. for 48 hours. 1T bend 1T bend using hand
-operated Very light Pass die. The panels were then copper taped,
the bend radii were sulfate then wiped with copper stain after
sulphate as described in taping a Example 2. 1-T bend 80 inch # All
the panels were subjected Very light Pass Reverse- to an 80 pound
ball. The copper Impact panels were then taped and sulfate Test
bend radii were wiped with stain after copper sulfate as in Example
taping a 2. 1-T bend Forming Limited Dome Height Equal to Pass Test
Testing was performed as in competitive Example 2. product Cleana-
Clean with PCL 75LC as per Cleanable Pass bility TPB 232070 (2%
@110.degree. F. with for 60 sec) as in Example 2. alkaline cleaner
- Water Break Free Blocking Blocking was tested using No block-
Pass Test Carver Hydraulic Equipment ing @ @ 5000-6000 psi @
140.degree. F. as 140.degree. F. in Example 4.
[0079] Thus, it is believed that compositions of the present
invention are surprisingly better anti-corrosive and anti-blocking
compositions than known compounds.
[0080] The disclosures of each patent, patent application, and
publication cited or described in this document are hereby
incorporated herein by reference, in their entireties.
[0081] Various modifications of the invention, in addition to those
described herein, will be apparent to those skilled in the art from
the foregoing description. Such modifications are also intended to
fall within the scope of the appended claims.
* * * * *