CONDUCTIVE OR STATIC DISSIPATIVE COATING

REVETEMENT CONDUCTEUR OU DISSIPATIF STATIQUE

English Abstract

Electrically conductive or static dissipative coating, films, or laminae in a
laminate construction suitable for packaging of sensitive
electronic components. The electrical conductive or static dissipative
properties are achieved by including an effective amount of a quaternary
ammonium compound into a base resin.

French Abstract

La présente invention concerne un revêtement, des films, ou une lame dans une construction stratifiée, présentant des propriétés de conductivité électrique ou de dissipation statique, convenant au conditionnement de composants électroniques sensibles. On obtient ces propriétés de conductivité statique ou de dissipation statique en introduisant une quantité efficace d'un composé à base d'ammonium quaternaire dans une résine basique.

Claims

We claim:
1. A self sustaining film with a static dissipative property and a conductive
property
comprising: a composition including an acrylic resin base and a quaternary
ammonium
compound in an amount of about 1 to about 10 wt % based on the weight of the
composition.
2. The self sustaining film of claim 1, wherein said acrylic resin is a
methylmethacrylate
containing polymer.
3. The self sustaining film of claim 1, wherein the composition further
comprises a
dispersion of zinc oxide particles.
4. The self sustaining film of claim 1, wherein the composition further
comprises a
polyethylene wax emulsion.
5. A paper layer coated with a polymeric composition having a static
dissipative
property and a conductive property, the composition comprising: an acrylic
resin base
and a quaternary ammonium compound in an amount of about 1 to about wt % based
on the weight of the composition.
6. The paper layer of claim 5, wherein the said acrylic resin is a
methymethacrylate
containing polymer.
7. The paper layer of claim 5, wherein the composition further comprises a
dispersion
of zinc oxide particles.
8. The paper layer of claim 5, wherein the composition further comprises a
polyethylene wax emulsion.
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9. A laminate comprising two or more laminae coated on at least one surface of
a
laminae with a polymeric composition having a static dissipative property and
a
conductive property, the composition comprising: an acrylic resin base and a
quaternary
ammonium compound in an amount of about 1 to about 10 wt % based on the weight
of
the composition.
10. A package comprising a material selected from the group consisting of
paper,
fabric, non-woven material and combinations thereof and at least an outside
layer made
of a polymeric composition having a static dissipative property and a
conductive
property, the composition comprising: an acrylic resin base and a quaternary
ammonium compound in an amount of about 1 to about 10 wt % based on the weight
of
the composition.
11. The package of claim 10, wherein said at least one material further
comprises a
metallized surface.
12. The package of claim 10, wherein the material is paper.
13. The package of claim 12, wherein the composition further comprises a
dispersion of
zinc oxide particles.
14. The package of claim 12, wherein the composition further comprises a
polyethylene
wax emulsion.
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Description

CA 02365364 2001-08-23
WO 00/52709 PCTIUSOO/05438
CONDUCTIVE OR STATIC DISSIPATIVE COATING
Background of the Invention
1. Field of the Invention
This invention relates to a film, specifically a self-sustaining film or a
laminae in a
laminated construction or a coating for such laminated construction which is
electrically
conductive and/or possesses static electricity dissipative properties. These
materials can be used
especially to package electronic components which may be affected by or
damaged by the build-
up of static electricity during transportation, handling or storage of the
electronic part.
2. Back,ground of the Invention
Resinous materials, e.g. polymeric materials, are known to be useful for
formation of
coatings, self-sustaining films, laminae in laminated constructions and
coating thereon.
However, inherent in the use of polymeric materials is the fact that they are
typically non-
conductive to electricity and, in fact, such materials are used widely as
insulators because of
these non-conductive properties.
Prior attempts at imparting electrically conductive properties to polymers
include the
inclusion of conductive materials, especially a material such as carbon or
similar material, e.g.
graphite, as a filler to the polymeric material. The inclusion of a material
such as carbon is only
effective if it is provided in such an amount (by weight or volume) and
dispersed uniformly
throughout the polymeric material so as to form a continuous pathway for
transmission of
electrical energy. The inclusion of such large amounts of filler and the
problem of uniformly
dispersing a material such as carbon greatly influences the conductive
properties of the resulting
composite material. Due to its nature, i.e. its inherent color, the use of
carbon also imparts a
predominately black color to any polymeric material into which it is
incorporated in electrically
conductive amounts.

CA 02365364 2001-08-23
WO 00/52709 PCT/US00/05438
Therefore, there is a requirement in the packaging industry for materials
which are more
aesthetically pleasing than a black plastic film.
Summary of the Invention
A film or coating which is composed primarily of a polymeric material is
provided with
conductive or static dissipative properties having particular utility for
packaging electronic
components, which are subject to deterioration of properties by build-up of
static electricity
during storage, shipping and handling and/or electrically conductive materials
in a form of a self-
sustaining film, as a laminae in a laminated construction or as a coating on
paper or in a
laminated construction for the purpose of imparting conductive or static
dissipative properties
to the polymeric material. Such polymeric material having the conductive or
static dissipative
properties can be used as packaging materials, especially for packaging
electronic components.
Detailed Description of the Preferred Embodiments
Polymeric materials such as acrylic based polymers, especially
methylmethacrylate
containing polymers, are excellent for forming coatings and films because of
their physical
properties, especially their optical clarity. These properties make it
desirable to use such
materials as a component for packaging after manufacture. However, such
polymeric materials
do not conduct or transmit electrical energy and are generally known as
"insulators," i.e. are non-
conductive to electrical current.
The present invention discloses a novel formulation for imparting electrical
conductivity
or static dissipative properties to polymeric materials by mixing between
about 1 to about 10 wt
% of a material imparting a surface resistivity (as measured by ASTM D-257
test method
conducted at 12% relative humidity) so as to have a static dissipative
property of less than 1011
ohms/sq and a conductive property of less than 10' ohms/sq. A material
suitable for mixing with
1)

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WO 00/52709 PCT/USOO/05438
the polymeric material is a quatemary ammonium compound. These quateraary
ammonium
compounds, in a solvent/carrier of an alcohol, preferably an
isopropanol/ethanol mix, results in
a liquid material which is easily mixed with the polymeric material. The
quaternary ammonium
containing liquid preferably contains about 41 % by weight alcohol and most
preferably 40%
isopropanol and 1% ethanol. Quatemary ammonium salts have been used as
softeners, especi,ally
in laundry formulations, or as applied to paper or foam substrates introduced
during drying of
laundered clothes. However, no use of these materials as a component of a
film, laminate or
coating has been known prior to the invention. A suitable material can be
obtained from ACL
Inc., 1960 E. Devon Avenue. Elkgrove Village, Illinois 60007, under the name
"STATICIDE
3000G'." Such a material is commercially available in liquid cor~cet7traie
form appearing as a
clear yellow substance with a pleasant odor, having an evaporation rate
greater than water. As
sold, "STATICIDE 3000GT"' has a specific gravity of 0.97, a density (g/ml) of
0.97, a vapor
pressure (mm) at 20 C of 36 and a vapor density of 2.1. Percent volatiles (by
volume) is about
40% with a pH of 7.111.
After mixing the quateraary ammonium containing liquid with the polymeric
material,
the resulting composition can then be formed into a self-sustaining film or
used as a laminae of
a lamination construction or as a coating for paper or a lamination
construction. When used in
a lamination construction, the conductive or static dissipative containing
material of the present
invention should preferably be used as the outer layer, i.e. on one or both
sides of the film.
Between the outer layers of the film, additional laminae may include a
metallicized or non-
metallicized surface and one or more layers of plastic film, fabric, non-woven
material or paper,
each of which is either coated or non-coated with coatings. The mixture of
quatemary
ammonium containing liquid and other components can be formed into a film.
applied as a
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= CA 02365364 2008-06-04
WO 00/52709 PGT/US00/05438
coating or formed into a laminae by conventional techniques known to the art
for making other
polymeric films, coatings and/or laminae.
Typical requirements of a self-sustaining film would be one having a thickness
between
about 0.5 to about 500 mils and having a tensile strength (measured by ASTM D-
882 test method
of 0-100 lbs. per square inch). Puncture resistance (as measured by FTMS 101 C
method 2065)
is 0-150 lbs. The haze (as measured by ASTM D-1003 test method) is clear to
opaque; an optical
density (measured by the McBeth test method) of 0-4.0% and a light
transmission (measured by
ASTM D-1003 test method) of 0-100%. Seam strength of a film made into a
package as tested
by ASTM D-882 test method should destruct.
The best mode contemplated by the inventor for carrying out the invention is
illustrated
by the following examples:
Exam lp e 1(all narts being bv weigU
Parts Component
27.0 H20
2.6 NH4OH 28
336.0 Joncryl 82'
74.0 Joncryl6l" Tm
29.8 Jonwax 28"' '
15.0 Zinc Oxide Solution""
120.0 H20
3.0 - 60.0 Staticide 3000GTm
`Methylmethacrylate aqueous solution sold by S.C. Johnson & Sons, Inc., U.S.
Specialty Chemicals, 1525 Howe Street, Racine, Wisconsin.
"Methylmethacrylate aqueous solution sold by S.C. Johnson & Sons, Inc., U.S.
Specialty Chemicals, 1525 Howe Street, Racine, Wisconsin.
"'A polyethylene wax emulsion containing about 35% solids sold by S.C. Johnson
&
Sons, Inc.. U.S. Specialty Chemicals, 1525 Howe Street, Racine. Wisconsin.
""Actually a dispersion of zinc oxide particles in an aqueous vehicle.
4

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WO 00/52709 PCT/USOU/05438
Exg=le 2
Component
..s..
400.0 Spectra-Guard 763 TM
110.0 H20
4.0 - 20.0 3000-G Staticide TM Concentrate
Ex
~ Component
400.0 Spectra-Guard 763 Tm
110.0 H20
4.0-20.0 3000-G Staticide I Concentrate
5.0-25.0 Joncryl 89***'**
The foregoing examples illustrate a conductive material content of between
about I to
about 10% by weight sufficient to form a coating, a self-sustaining film
and/or a laminae in a
laminated construction providing the surface resistivity mentioned above.
The chemical properties including the property of contact corrosivity as
measured by
FTMS lO1C method 3005 showed no visible sign after testing of deterioration;
has an ion
content (sodium, fluoride, phosphate and sulfate ions) below detectable levels
and is amine and
amide free.
It will be apparent to those skilled in the art that I have provided a
formulation which
permits the attainment of a coating, film or laminated construction based
primarily on a
polymeric system which is static dissipative and/or conductive to electrical
energy, permitting
the formulation of aesthetic packaging materials, especialIy for packaging
electronic parts which
**'** A film forming material commercially available from Spectra-Kote
Corporation,
Fourth Street and East Water Street, Gettysburg, Pennsylvania and described in
U.S. Patents
5,393,566 and 5,531,863.
***"' Sold commercially by S. C. Johnson & Sons, Inc., U.S. Specialty
Chemicals,
1525 Howe Street, Racine, Wisconsin.

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WO 00/52709 PCT/US00/05438
can be damaged by static electricity during storage, shipping and/or handling.
However, it will
be apparent to those skilled in the art that other formulations and uses
thereof could be employed
without departing from the spirit and scope of the invention.
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