U.S. patent application number 14/118357 was filed with the patent office on 2014-04-03 for colored polyimide films and methods relating thereto.
This patent application is currently assigned to E I DU PONT DE NEMOURS AND COMPANY. The applicant listed for this patent is Christopher Robert Becks, Kuppusamy Kanakarajan. Invention is credited to Christopher Robert Becks, Kuppusamy Kanakarajan.
Application Number | 20140093714 14/118357 |
Document ID | / |
Family ID | 46457047 |
Filed Date | 2014-04-03 |
United States Patent
Application |
20140093714 |
Kind Code |
A1 |
Becks; Christopher Robert ;
et al. |
April 3, 2014 |
COLORED POLYIMIDE FILMS AND METHODS RELATING THERETO
Abstract
The present disclosure is directed to a colored polyimide film
having 48 to 94 weight percent of a polyimide, 5 to 25 weight
percent pigment and 0.05 to 2 weight percent carbon black. The
polyimide is derived is derived from at least one aromatic diamine
and at least one aromatic dianhydride. The colored polyimide film
has an optical density of at least 1.4
Inventors: |
Becks; Christopher Robert;
(Grove City, OH) ; Kanakarajan; Kuppusamy;
(Dublin, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Becks; Christopher Robert
Kanakarajan; Kuppusamy |
Grove City
Dublin |
OH
OH |
US
US |
|
|
Assignee: |
E I DU PONT DE NEMOURS AND
COMPANY
Wilmington
DE
|
Family ID: |
46457047 |
Appl. No.: |
14/118357 |
Filed: |
June 18, 2012 |
PCT Filed: |
June 18, 2012 |
PCT NO: |
PCT/US12/42865 |
371 Date: |
November 18, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61500852 |
Jun 24, 2011 |
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61500866 |
Jun 24, 2011 |
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61500877 |
Jun 24, 2011 |
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61500906 |
Jun 24, 2011 |
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61500918 |
Jun 24, 2011 |
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61500943 |
Jun 24, 2011 |
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Current U.S.
Class: |
428/220 |
Current CPC
Class: |
C08K 3/22 20130101; C08K
3/04 20130101 |
Class at
Publication: |
428/220 |
International
Class: |
C08K 3/04 20060101
C08K003/04 |
Claims
1. A colored polyimide film comprising: i) 48 to 94 weight percent
of a polyimide, the polyimide is derived from at least one aromatic
diamine and at least one aromatic dianhydride; ii) 5 to 25 weight
percent of a pigment; iii) 0.05 to 2 weight percent of a carbon
black; wherein the colored polyimide film has a thickness is from 8
to 152 microns; and wherein the colored polyimide film has an
optical density of at least 1.4 as measured with a Macbeth TD904
optical densitometer.
2. The colored polyimide film of claim 1 wherein the carbon black
is present in an amount from 0.1 to 1 weight percent.
3. The colored polyimide film of claim 1 wherein the carbon black
is present in an amount from 0.5 to 1 weight percent.
4. The colored polyimide film of claim 1 additionally comprising 10
to 25 weight percent of a filler selected from the group consisting
of: thermally conductive fillers, dielectric fillers, electrically
conductive fillers and mixtures thereof.
5. The colored polyimide film of claim 1 additionally comprising 10
to 25 weight percent of a filler selected from the group consisting
of: talc, mica, silica, kaolin, titanium dioxide, boron nitride,
barium titanate, sepiolite, aluminum nitride and mixtures
thereof.
6. The colored polyimide film of claim 1 wherein the pigment is
selected from, diketopyrrolopyrrole pigment, Perylene Red or
Ultramarine Blue.
7. The colored polyimide film of claim 1 wherein the carbon black
is selected from the group consisting of: a carbon black having a
volatile content greater than or equal to 13%, a furnace black, a
channel black and mixtures thereof.
8. The colored polyimide film of claim 1 wherein the polyimide is
derived from pyromellitic dianhydride and 4,4'-oxydianiline.
9. The colored polyimide film of claim 1 wherein the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine.
10. The colored polyimide film of claim 1 wherein the polyimide is
derived from at least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide.
11. The colored polyimide film of claim 1 wherein the polyimide is
derived from pyromellitic dianhydride, 4,4'-oxydianiline and
paraphenylene diamine.
Description
FIELD OF DISCLOSURE
[0001] The present disclosure relates generally to colored
polyimide films. More specifically, the colored polyimide films of
the present disclosure are useful in coverlay applications.
BACKGROUND OF THE DISCLOSURE
[0002] Broadly speaking, coverlays are known as barrier films for
protecting electronic materials, e.g., for protecting flexible
printed circuit boards, electronic components, leadframes of
integrated circuit packages and the like. A need exists however,
for coverlays to be increasingly thin and low in cost, while not
only having acceptable electrical properties (e.g., dielectric
strength), but also having acceptable mechanical and optical
properties to provide security against unwanted visual inspection
and tampering of the electronic components protected by the
coverlay.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The disclosure is illustrated by way of example and not
limited by the accompanying figures.
[0004] FIG. 1 is a plot of optical density verses opacifying agent
loading level.
SUMMARY
[0005] The present disclosure is directed to a colored polyimide
film comprising:
[0006] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from at least one aromatic diamine and at least one
aromatic dianhydride;
[0007] ii) 5 to 25 weight percent of a pigment;
[0008] iii) 0.05 to 2 weight percent of a carbon black;
wherein the colored polyimide film has a thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured with a Macbeth TD904 optical
densitometer.
DETAILED DESCRIPTION
Definitions
[0009] As used herein, the terms "comprises," "comprising,"
"includes," "including," "has," "having" or any other variation
thereof, are intended to cover a non-exclusive inclusion. For
example, a method, process, article, or apparatus that comprises a
list of elements is not necessarily limited only to those elements
but may include other elements not expressly listed or inherent to
such method, process, article, or apparatus. Further, unless
expressly stated to the contrary, "or" refers to an inclusive or
and not to an exclusive or. For example, a condition A or B is
satisfied by any one of the following: A is true (or present) and B
is false (or not present), A is false (or not present) and B is
true (or present), and both A and B are true (or present).
[0010] Also, use of the "a" or "an" are employed to describe
elements and components of the invention. This is done merely for
convenience and to give a general sense of the invention. This
description should be read to include one or at least one and the
singular also includes the plural unless it is obvious that it is
meant otherwise.
[0011] "Dianhydride" as used herein is intended to include
precursors or derivatives thereof, which may not technically be a
dianhydride but would nevertheless react with a diamine to form a
polyamic acid which could in turn be converted into a
polyimide.
[0012] "Diamine" as used herein is intended to include precursors
or derivatives thereof, which may not technically be a diamine but
would nevertheless react with a dianhydride to form a polyamic acid
which could in turn be converted into a polyimide.
[0013] "Polyamic acid" as used herein is intended to include any
polyimide precursor material derived from a combination of
dianhydride and diamine monomers or functional equivalents thereof
and capable of conversion to a polyimide via a chemical or thermal
conversion process.
[0014] "Prepolymer" as used herein is intended to mean a relatively
low molecular weight polyamic acid solution which is prepared by
using a stoichiometric excess of diamine in order to give a
solution viscosity of approximately 50-100 Poise.
[0015] "Chemical conversion" or "chemically converted" as used
herein denotes the use of a catalyst (accelerator) or dehydrating
agent (or both) to convert the polyamic acid to polyimide and is
intended to include a partially chemically converted polyimide
which is then dried at elevated temperatures to a solids level
greater than 98%.
[0016] "Conversion chemical(s)" as used herein denotes a catalyst
(accelerator) or a dehydrating agent (or both) used to convert the
polyamic acid to polyimide.
[0017] "Colored polyimide composition" as used herein is intended
to include any polyimide precursor material capable of conversion
to a polyimide and containing a pigment, and may or may not be in
solution (solvent) and may or may not contain filler.
[0018] "Imidized" as used herein is intended to mean when a
polyamic acid undergoes ring closure (imidization) to form a
polyimide.
[0019] When an amount, concentration, or other value or parameter
is given as either a range, preferred range or a list of upper
preferable values and lower preferable values, this is to be
understood as specifically disclosing all ranges formed from any
pair of any upper range limit or preferred value and any lower
range limit or preferred value, regardless of whether ranges are
separately disclosed. Where a range of numerical values is recited
herein, unless otherwise stated, the range is intended to include
the endpoints thereof, and all integers and fractions within the
range. It is not intended that the scope of the invention be
limited to the specific values recited when defining a range.
[0020] In describing certain polymers it should be understood that
sometimes applicants are referring to the polymers by the monomers
used to make them or the amounts of the monomers used to make them.
While such a description may not include the specific nomenclature
used to describe the final polymer or may not contain
product-by-process terminology, any such reference to monomers and
amounts should be interpreted to mean that the polymer is made from
those monomers, unless the context indicates or implies
otherwise.
[0021] The materials, methods, and examples herein are illustrative
only and, except as specifically stated, are not intended to be
limiting. Although methods and materials similar or equivalent to
those described herein can be used, suitable methods and materials
are described herein.
Overview
[0022] The colored polyimide films of the present disclosure
comprise a low amount of carbon black. Colored polyimide films
containing a low amount of carbon black have a higher optical
density (opacity) when compared to a colored polyimide film
containing the same amount or more of a non-carbon black opacifying
agent.
Polyimide
[0023] The polyimide of the present disclosure is derived from at
least one aromatic diamine and at least one aromatic dianhydride.
In some embodiment, the aromatic dianhydride is selected from the
group consisting of: 3,3',4,4'-benzophenone tetracarboxylic
dianhydride, 4,4'-oxydiphthalic anhydride, 3,3',4,4'-diphenyl
sulfone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)
hexafluoropropane, bisphenol A dianhydride, mixtures and
derivatives thereof. In another embodiment, the aromatic
dianhydride is selected from the group consisting of:
2,3,6,7-naphthalene tetracarboxylic dianhydride,
1,2,5,6-naphthalene tetracarboxylic dianhydride, 2,2',3,3'-biphenyl
tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl) propane
dianhydride, bis(3,4-dicarboxyphenyl) sulfone dianhydride,
3,4,9,10-perylene tetracarboxylic dianhydride,
1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride,
1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride,
bis(2,3-dicarboxyphenyl) methane dianhydride,
bis(3,4-dicarboxyphenyl) methane dianhydride, oxydiphthalic
dianhydride, bis(3,4-dicarboxyphenyl) sulfone dianhydride, mixtures
and derivatives thereof. In another embodiment, the aromatic
dianhydride is selected from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic diandydride or mixtures
thereof.
[0024] In some embodiment, the aromatic diamine is selected from a
group consisting of: 3,4'-oxydianiline, 1,3-bis-(4-aminophenoxy)
benzene, 1,4-diaminobenzene, 1,3-diaminobenzene,
2,2'-bis(trifluoromethyl) benzidene, 4,4'-diaminobiphenyl,
4,4'-diaminodiphenyl sulfide, 9,9'-bis(4-amino)fluorine, mixtures
and derivatives thereof. In another embodiment, the aromatic
diamine is selected from a group consisting of:
4,4'-diaminodiphenyl propane, 4,4'-diamino diphenyl methane,
benzidine, 3,3'-dichlorobenzidine, 3,3'-diamino diphenyl sulfone,
4,4'-diamino diphenyl sulfone, 1,5-diamino naphthalene,
4,4'-diamino diphenyl diethylsilane, 4,4'-diamino diphenysilane,
4,4'-diamino diphenyl ethyl phosphine oxide, 4,4'-diamino diphenyl
N-methyl amine, 4,4'-diamino diphenyl N-phenyl amine,
1,2-diaminobenzene, mixtures and derivatives thereof. In another
embodiment, the aromatic diamine is selected from
4,4'-oxydianiline, paraphenylene diamine or mixtures thereof
[0025] In some embodiments, the polyimide is derived from
pyromellitic dianhydride and 4,4'-oxydianiline. In some
embodiments, the polyimide is derived from 100 mole percent
pyromellitic dianhydride and 100 mole percent 4,4'-oxydianiline. In
some embodiments, the polyimide is derived from pyromellitic
dianhydride, 3,3',4,4'-biphenyltetracarboxylic diandydride,
4,4'-oxydianiline and paraphenylene diamine.
[0026] In some embodiments, the polyimide is derived from:
[0027] 15 to 85 mole percent of biphenyltetracarboxylic
dianhydride,
[0028] 15 to 85 mole percent pyromellitic dianhydride,
[0029] 30 to 100 mole percent paraphenylene diamine and optionally
including
[0030] 0 to 70 mole percent of 4,4'-oxydianiline.
[0031] In some embodiments, the polyimide is derived from
pyromellitic dianhydride, 4,4'-oxydianiline and paraphenylene
diamine. In some embodiments, the polyimide is derived from
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine. In some embodiments, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic diandydride and
4,4'-oxydianiline. In some embodiments, the polyimide is derived
from pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic
dianhydride and paraphenylene diamine. In some embodiments, the
polyimide is derived from 3,3',4,4'-biphenyltetracarboxylic
dianhydride and paraphenylene diamine. In some embodiments, the
polyimide is derived from 3,3',4,4'-biphenyltetracarboxylic
dianhydride and 4,4'-oxydianiline. In some embodiments, the
polyimide is derived from pyromellitic dianhydride and
paraphenylene diamine.
[0032] In some embodiments, the polyimide is a low color polyimide.
Typically polyimides have some color ranging from yellow to
orange/brown. The advantage of a low color polyimide is that when a
pigment is added to the polyimide, the resulting colored polyimide
film is more true to the color of the pigment. In some embodiments,
the polyimide is derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide. In some embodiments, the polyimide is
derived from at least 50 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide. In some embodiments, the polyimide is
derived from 90 mole percent of 3,3',4,4'-biphenyltetracarboxylic
dianhydride, based on a total dianhydride content of the polyimide
and 100 mole percent of 2,2'-bis(trifluoromethyl) benzidine. In
some embodiments, the polyimide is derived from 100 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, and 100 mole percent
of 2,2'-bis(trifluoromethyl) benzidine. In some embodiments, the
polyimide is derived from 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride and 55 mole percent
of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride based on a
total dianhydride content of the polyimide, and at least 50 mole
percent of 2,2'-bis(trifluoromethyl) benzidine based on a total
diamine content of the polyimide.
[0033] In some embodiments, the polyimide is a thermoplastic
polyimide. In some embodiments the polyimide is derived from
oxydiphthalic dianhydride, pyromellitic dianhydride and
1,3-bis-(4-aminophenoxy) benzene. In some embodiments, the
polyimide is derived from oxydiphthalic dianhydride, pyromellitic
dianhydride, 1,3-bis-(4-aminophenoxy) benzene and hexamethylene
diamine. In some embodiments, the polyimide is derived from
biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone
tetracarboxylic dianhydride, 1,3-bis-(4-aminophenoxy) benzene and
hexamethylene diamine.
[0034] In one embodiment, the polyimide is present in an amount
between and optionally including any two of the following numbers:
48, 50, 55, 60, 65, 70, 75, 80, 84, 90 and 94 weight percent based
on the total weight of the colored polyimide film. In some
embodiments, the polyimide is present in an amount from 48 to 94
weight percent based on the total weight of the colored polyimide
film. In another embodiment, the polyimide is present amount
between and optionally including any two of the following numbers:
73, 75, 80, 85, 90 and 94 weight percent based on the total weight
of the colored polyimide film. In another embodiment, the polyimide
is present in an amount from 73 to 94 weight percent based on the
total weight of the colored polyimide film. In another embodiment,
the polyimide is present in an amount from 48 to 84 weight percent
based on the total weight of the colored polyimide film.
Pigment
[0035] While virtually any pigment (or combination of pigments) can
be used in the present disclosure. It is to be understood that
carbon black, for the purpose of the present disclosure, is not
used as a pigment to color to the polyimide film but rather to
increase the optical density.
[0036] WO2011017291 to Carney, et al. discloses the amount of low
conductivity carbon black and the thickness of the base film will
generally impact the optical density. If the low conductivity
carbon black loading level is unduly high, the base film will be
conductive even when a low conductivity carbon black is used. If
too low, the base film may not achieve the desired optical density
and color. The low conductivity carbon black, in WO2011017291, is
used to impart the black color to the base film as well as to
achieve the desired optical density of a base film having a
thickness from 8 to 152 microns. The low conductivity carbon black
is used as the pigment in amounts to achieve the desired black
color and desired optical density. It does not recognize that low
amounts of carbon black increase the optical density of a film more
than if a non-carbon black opacifying agent is used in the same
amount. In some embodiments, the non-carbon black opacifying agent
is TiO2 or paliogen black (an organic black pigment). In another
embodiment, the non-carbon black opacifying agent can be additional
pigment.
[0037] Some examples of useful pigments include but are not limited
to Barium Lemon Yellow, Cadmium Yellow Lemon, Cadmium Yellow Lemon,
Cadmium Yellow Light, Cadmium Yellow Middle, Cadmium Yellow Orange,
Scarlet Lake, Cadmium Red, Cadmium Vermilion, Alizarin Crimson,
Permanent Magenta, Van Dyke brown, Raw Umber Greenish or Burnt
Umber.
[0038] In some embodiments, the pigment is selected from,
diketopyrrolopyrrole pigment, Perylene Red or Ultramarine Blue. In
some embodiments, the pigment is selected from Pigment Blue 29,
Pigment Red 264, or Pigment Red 178. In some embodiments, the
pigment is 1,4-Diketo-3,6-bis(4-biphenylyl)pyrrolo[3,4-c]pyrrole
(Cinilex DPP Rubine SR5H available from Cinic Chemicals America
LLC). In some embodiments, the pigment is
2,9-Bis[4-(phenylazo)phenyl]anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-
-1,3,8,10(2H,9H)-tetrone (Paliogen Red L-3880 available from BASF).
In some embodiments, the pigment is Ultramarine Blue FP-40,
available from Nubiola.
[0039] In some embodiments, the pigment is present in an amount
between and optionally including any two of the following: 5, 10,
15, 20 and 25 weight percent based on the total weight of the
colored polyimide film. In some embodiments, the pigment is present
in an amount from 5 to 25 weight percent based on the total weight
of the colored polyimide film.
[0040] In some embodiments, the pigment is milled. A uniform
dispersion of isolated, individual pigment particles (aggregates)
tends to produce uniform color intensity.
Carbon Black
[0041] Carbon black is used in the present disclosure to increase
the optical density of a colored polyimide film. Surprisingly, low
amounts of carbon black (0.05 to 2 weight percent) provide an
increase in optical density that is not achieved when non-carbon
black opacifying agents are used in the same amount or even used in
greater amounts.
[0042] Some non-carbon black opacifying agents commonly used to
increase optical density are, but not limited to, titanium dioxide
and zinc oxide. In some embodiments, pigments are used as
opacifying agents.
[0043] Pigments or non-carbon black opacifying agents must be used
in higher amounts to achieve the same optical density as low
amounts of carbon black (0.05 to 2 weight percent). In some
embodiments, if carbon black is not used, three times the amount of
pigment is needed to achieve an optical density of at least 1.4 as
measured with a Macbeth TD904 optical densitometer. In some
embodiments, five times the amount of anon-carbon black opacifying
agent is needed. As the amount of a filler (pigment and other
particle additives) increases, the more brittle a film tends to
become, making the film more difficult to handle during the
manufacturing process. Thus, the use of carbon black is also
advantageous for mechanical properties and ease of manufacture due
to the lower amounts needed to produce a desirable optical density
of at least 1.4 as measured with a Macbeth TD904 optical
densitometer.
[0044] Another advantage of using low amounts of carbon black in
accordance with the present disclosure is a lower overall cost
colored polyimide film. Low amounts of inexpensive carbon black is
used to reach a desired optical density. In some embodiments, the
optical density (opacity) desirable (for example, to hide the
conductor traces in the flex circuits from view) is greater than or
equal to 1.4 as measured with a Macbeth TD904 optical densitometer.
An optical density of 1.4 is intended to mean 1.times.10.sup.-1.4
or 3.98% of light is transmitted through the colored polyimide
film. In some embodiments, the optical density (opacity) desirable
is greater than or equal to 1.8 as measured with a Macbeth TD904
optical densitometer. In another embodiment, the colored polyimide
film optical density is at least 2 as measured with a Macbeth TD904
optical densitometer.
[0045] Even though low amounts of carbon black are used, it would
be desirable for the carbon black to be a low conductivity carbon
black as to not increase the electrical conductivity of the colored
polyimide film. Low conductivity carbon black is intended to mean,
a channel black, a furnace black or a surface oxidized carbon
black. One method for assessing the extent of surface oxidation (of
the carbon black) is to measure the carbon black's volatile
content. The volatile content can be measured by calculating weight
loss when calcined at 950.degree. C. for 7 minutes. In some
embodiments, the carbon black has a volatile content greater than
or equal to 1%. In some embodiments, the carbon black has a
volatile content greater than or equal to 5%. In some embodiments,
the carbon black has a volatile content greater than or equal to
10%. In some embodiments, the carbon black has a volatile content
greater than or equal to 13%. In some embodiments, the carbon black
is selected from the group consisting of: a carbon black having a
volatile content greater than or equal to 13%, a furnace black, a
channel black and mixtures thereof.
[0046] Channel black (channel type black) typically uses a
combination of oil and gas as feedstock, and the traditional
channels are replaced by water cooled rollers. A series of small
flames impinge on the cooled rollers to deposit the carbon black.
The product is scraped off the rollers and collected. This "channel
type" process is also known as "roller impingement", and produces
products that are basically similar to the classic channel blacks.
They typically have a volatile content of up to 5% and if
post-treated up to 17%.
[0047] In some embodiments, furnace black may be surface treated to
increase the volatile content. In some embodiments, the carbon
black is Special Black 4, from Evonik Degussa. Generally speaking,
a highly surface oxidized carbon black (high volatile content) can
be readily dispersed into a polyamic acid solution (polyimide
precursor), which in turn can be imidized into a polyimide
film.
[0048] For the purpose of the present disclosure, the carbon black
is present in an amount from 0.05 to 2 weight percent based on the
total weight of the colored polyimide film. In some embodiments,
the carbon black is present in an amount between and optionally
including any two of the following: 0.05, 0.1, 0.5, 1 and 2 weight
percent based on the total weight of the colored polyimide film. In
some embodiments, the carbon black is present in an amount from 0.1
to 2 weight percent based on the total weight of the colored
polyimide film. In another embodiment, the carbon black is present
in an amount from 0.5 to 2 weight percent based on the total weight
of the colored polyimide film. In another embodiment, the carbon
black is present in an amount from 0.05 to 1 weight percent based
on the total weight of the colored polyimide film. In another
embodiment, the carbon black is present in an amount from 0.1 to 1
weight percent based on the total weight of the colored polyimide
film. In another embodiment, the carbon black is present in an
amount from 0.5 to 1 weight percent based on the total weight of
the colored polyimide film. If carbon black is present in greater
than 2 weight percent the color of the film significantly changes.
For example, when pigment of the colored polyimide film is a red
pigment and greater than 2 weight percent carbon black is used, the
resulting film visually looks closer to black not red as intended
by the addition of red pigment.
Colored Polyimide Film
[0049] The colored polyimide film of the present disclosure
comprises: [0050] i) 48 to 94 weight percent of a polyimide, the
polyimide is derived from at least one aromatic diamine and at
least one aromatic dianhydride; [0051] ii) 5 to 25 weight percent
of a pigment; [0052] iii) 0.05 to 2 weight percent of a carbon
black; wherein the colored polyimide film has a thickness is from 8
to 152 microns; and wherein the colored polyimide film has an
optical density of at least 1.4 as measured with a Macbeth TD904
optical densitometer.
[0053] In some embodiments, the colored polyimide films of the
present disclosure are useful as coverlays for protecting
electronic materials, e.g., for protecting flexible printed circuit
boards, electronic components, leadframes of integrated circuit
packages and the like. Coverlays need to be thin and low in cost,
while having acceptable electrical properties, mechanical
properties and optical density to provide security against unwanted
visual inspection and tampering of the electronic components
protected by the coverlay.
[0054] In some embodiments, the colored polyimide film optical
density is at least 1.4 as measured with a Macbeth TD904 optical
densitometer. In another embodiment, the colored polyimide film
optical density is at least 1.8 as measured with a Macbeth TD904
optical densitometer. In another embodiment, the colored polyimide
film optical density is at least 2 as measured with a Macbeth TD904
optical densitometer.
[0055] In some embodiments, the optical density of the colored
polyimide film is increased by at least 8 percent when 0.1 weight
percent carbon black is used compared to a colored polyimide film
with the same amount of pigment but no carbon black present. In
some embodiments, the optical density of the colored polyimide film
is increased by at least 27 percent when 0.1 weight percent carbon
black is used compared to a colored polyimide film with the same
amount of pigment but no carbon black present. In some embodiments,
the optical density of the colored polyimide film is increased by
at least 30 percent when 0.5 weight percent carbon black is used
compared to a colored polyimide film with the same amount of
pigment but no carbon black present. In some embodiments, the
optical density of the colored polyimide film is increased by at
least 47 percent when 1 weight percent carbon black is used
compared to a colored polyimide film with the same amount of
pigment but no carbon black present. In some embodiments, the
optical density of the colored polyimide film is increased by at
least 59 percent when 1 weight percent carbon black is used
compared to a colored polyimide film with the same amount of
pigment but no carbon black present.
[0056] Carbon black is advantageous over other non-carbon black
opacifying agents. Other non-carbon black opacifying agents do not
produce colored polyimide films with the same optical density as
when carbon black is used. A larger amount of an non-carbon black
opacifying agent is needed to produce a colored polyimide film with
equivalent optical density. In some embodiments, at least twenty
times the amount of an non-carbon black opacifying agent (compared
to carbon black) is needed to produce a colored polyimide film with
an equivalent optical density. In another embodiment, the optical
density of the colored polyimide film is increased by at least 10
percent compared to a colored polyimide film incorporating a
non-carbon black opacifying agent at the same weight percent. In
another embodiment, the optical density of the colored polyimide
film is increased by at least 15 percent compared to a colored
polyimide film incorporating an non-carbon black opacifying agent
at the same weight percent. In another embodiment, the optical
density of the colored polyimide film is increased by at least 20
percent compared to a colored polyimide film incorporating an
non-carbon black opacifying agent at the same weight percent. In
another embodiment, the optical density of the colored polyimide
film is increased by at least 30 percent compared to a colored
polyimide film incorporating an non-carbon black opacifying agent
at the same weight percent. In another embodiment, the optical
density of the colored polyimide film is increased by at least 40
percent compared to a colored polyimide film incorporating an
non-carbon black opacifying agent at the same weight percent. In
another embodiment, the optical density of the colored polyimide
film is increased by at least 50 percent compared to a colored
polyimide film incorporating an non-carbon black opacifying agent
at the same weight percent. In another embodiment, the optical
density of the colored polyimide film is increased by at least 52
percent compared to a colored polyimide film incorporating an
non-carbon black opacifying agent at the same weight percent.
[0057] Carbon black is advantageous over organic black pigments.
Organic black pigments (for example, paliogen black), do not
produce colored polyimide films with the same optical density as
when carbon black is used. A larger amount of organic black pigment
is needed to produce a colored polyimide film with equivalent
optical density. In some embodiments, at least five times the
amount of an organic black pigment (compared to carbon black) is
needed to produce a colored polyimide film with an equivalent
optical density. In some embodiments, the optical density is
increased at least 20 percent using carbon black compared to using
the same amount of organic black pigment.
[0058] Different pigments have different tinting strengths, with
carbon black having a high tinting strength. Thus, the amount of
color change imparted by the incorporation of carbon black, in
accordance with the embodiments of the present disclosure, will
depend on the pigment used and the amount of pigment used. Low
amounts of carbon black in accordance with the present disclosure
will change the color of the polyimide film. It is desirable to
maintain some shade of the color imparted by the pigment. For
example, when a blue pigment is used, the addition of low amounts
of carbon black will darken the color of the colored polyimide film
but the colored polyimide film is still a blue color. Generally
there is a practical threshold for the amount of carbon black,
above which, the optical density will taper off and the colored
polyimide film will visually appear black. Above the threshold,
large amounts of pigment would have to be added to retain color of
the colored polyimide film. The colored polyimide film would be too
brittle and would defeat the advantages of utilizing low amounts of
carbon black. In some embodiments, the ratio of the amount of
pigment to the amount of carbon black is 250, 200, 150, 100, 50,
30, 15 or 5 to 1. For a ratio less than 5 to 1 the film will
visually appear black which is undesirable for the purpose of this
disclosure.
[0059] The amount of pigment and the amount of carbon black can be
tailored to obtain desired optical density and desired color. The
advantages of the colored polyimide film of the present disclosure
are i. lower overall cost, ii. better mechanical properties (e.g.,
less brittle) thus easily handled during the manufacturing process
and iii. a optical density high enough to hide any circuit traces
underneath for a film thickness from 8 to 152 microns.
[0060] In some embodiments, the colored polyimide film additionally
comprises filler. The selection of filler is dependant on the
desired use of the colored polyimide film. For example, boron
nitride can be added to increase the thermal conductivity of the
colored polyimide film. The more boron nitride added, the greater
the thermal conductivity. In some embodiments, the colored
polyimide film additionally comprises 10 to 25 weight percent of a
thermally conductive filler. In another embodiment, the colored
polyimide film additionally comprises 10 to 25 weight percent of a
dielectric filler. In another embodiment, the colored polyimide
film additionally comprises 10 to 25 weight percent of a
electrically conductive filler. In some embodiments, a filler may
be added to control the coefficient of thermal expansion (CTE). In
some embodiments, the colored polyimide film additionally comprises
10 to 25 weight percent of a filler selected from the group
consisting of: thermally conductive fillers, dielectric fillers,
electrically conductive fillers and mixtures thereof. In some
embodiments, the colored polyimide film additionally comprises 10
to 25 weight percent of a filler selected from the group consisting
of: talc, mica, silica, kaolin, titanium dioxide, boron nitride,
barium titanate, sepiolite, aluminum nitride and mixtures
thereof.
[0061] In some embodiments, the colored polyimide film comprises:
[0062] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from at least one aromatic diamine and at least one
aromatic dianhydride; [0063] ii) 5 to 25 weight percent of a
pigment; [0064] iii) 0.05 to 2 weight percent of a carbon black;
wherein the colored polyimide film has a thickness is from 8 to 152
microns; and; wherein the colored polyimide film has an optical
density of at least 1.4 as measured with a Macbeth TD904 optical
densitometer.
[0065] In some embodiments, the colored polyimide film comprises:
[0066] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride and 4,4'-oxydianiline; [0067]
ii) 5 to 25 weight percent of pigment; [0068] iii) 0.05 to 2 weight
percent carbon black; wherein the colored polyimide film thickness
is from 8 to 152 microns; and wherein the colored polyimide film
has an optical density of at least 1.4 as measured by measured with
a Macbeth TD904 optical densitometer.
[0069] In some embodiments, the colored polyimide film
comprises:
[0070] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride and 4,4'-oxydianiline;
[0071] ii) 5 to 25 weight percent of pigment;
[0072] iii) 0.1 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.8 as measured by measured with a Macbeth
TD904 optical densitometer.
[0073] In some embodiments, the colored polyimide film
comprises:
[0074] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride and 4,4'-oxydianiline;
[0075] ii) 5 to 25 weight percent of pigment;
[0076] iii) 0.1 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0077] In some embodiments, the colored polyimide film
comprises:
[0078] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride and 4,4'-oxydianiline;
[0079] ii) 5 to 25 weight percent of pigment;
[0080] iii) 0.5 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0081] In another embodiment, the colored polyimide film
comprises:
[0082] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride and 4,4'-oxydianiline;
[0083] ii) 5 to 25 weight percent of pigment;
[0084] iii) 0.5 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.8 as measured by measured with a Macbeth
TD904 optical densitometer.
[0085] In another embodiment, the colored polyimide film
comprises:
[0086] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride and 4,4'-oxydianiline;
[0087] ii) 5 to 25 weight percent of pigment;
[0088] iii) 0.05 to 2 weight percent carbon black;
[0089] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0090] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0091] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride and 4,4'-oxydianiline;
[0092] ii) 5 to 25 weight percent of pigment;
[0093] iii) 0.05 to 2 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0094] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0095] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride and 4,4'-oxydianiline;
[0096] ii) 5 to 25 weight percent of pigment;
[0097] iii) 0.05 to 2 weight percent carbon black;
[0098] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0099] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0100] i) 48 to 84 weight percent of a polyimide, from pyromellitic
dianhydride and 4,4'-oxydianiline;
[0101] ii) 5 to 25 weight percent of pigment;
[0102] iii) 0.1 to 1 weight percent carbon black;
[0103] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0104] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0105] i) 48 to 84 weight percent of a polyimide, from pyromellitic
dianhydride and 4,4'-oxydianiline;
[0106] ii) 5 to 25 weight percent of pigment;
[0107] iii) 0.5 to 1 weight percent carbon black;
[0108] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0109] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0110] i) 48 to 84 weight percent of a polyimide, from pyromellitic
dianhydride and 4,4'-oxydianiline;
[0111] ii) 5 to 25 weight percent of pigment;
[0112] iii) 0.1 to 1 weight percent carbon black;
[0113] wherein the colored polyimide film has an optical density of
at least 1.4 as measured by measured with a Macbeth TD904 optical
densitometer; and wherein the carbon black is selected from the
group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0114] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0115] i) 48 to 84 weight percent of a polyimide, from pyromellitic
dianhydride and 4,4'-oxydianiline;
[0116] ii) 5 to 25 weight percent of pigment;
[0117] iii) 0.5 to 1 weight percent carbon black;
[0118] wherein the colored polyimide film thickness is from 8 to
152 microns; wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer; and wherein the carbon black is
selected from the group consisting of: a carbon black having a
volatile content greater than or equal to 13%, a furnace black, a
channel black and mixtures thereof.
[0119] In some embodiments, the colored polyimide film
comprises:
[0120] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic diandydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0121] ii) 5 to 25 weight percent of pigment;
[0122] iii) 0.05 to 2 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0123] In some embodiments, the colored polyimide film
comprises:
[0124] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0125] ii) 5 to 25 weight percent of pigment;
[0126] iii) 0.1 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.8 as measured by measured with a Macbeth
TD904 optical densitometer.
[0127] In some embodiments, the colored polyimide film
comprises:
[0128] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0129] ii) 5 to 25 weight percent of pigment;
[0130] iii) 0.1 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0131] In some embodiments, the colored polyimide film
comprises:
[0132] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0133] ii) 5 to 25 weight percent of pigment;
[0134] iii) 0.5 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0135] In another embodiment, the colored polyimide film
comprises:
[0136] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0137] ii) 5 to 25 weight percent of pigment;
[0138] iii) 0.5 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.8 as measured by measured with a Macbeth
TD904 optical densitometer.
[0139] In another embodiment, the colored polyimide film
comprises:
[0140] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0141] ii) 5 to 25 weight percent of pigment;
[0142] iii) 0.05 to 2 weight percent carbon black;
[0143] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof; and
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0144] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0145] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0146] ii) 5 to 25 weight percent of pigment;
[0147] iii) 0.05 to 2 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0148] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0149] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0150] ii) 5 to 25 weight percent of pigment;
[0151] iii) 0.05 to 2 weight percent carbon black;
[0152] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0153] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0154] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0155] ii) 5 to 25 weight percent of pigment;
[0156] iii) 0.1 to 1 weight percent carbon black;
[0157] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0158] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0159] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0160] ii) 5 to 25 weight percent of pigment;
[0161] iii) 0.5 to 1 weight percent carbon black;
[0162] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0163] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0164] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0165] ii) 5 to 25 weight percent of pigment;
[0166] iii) 0.1 to 1 weight percent carbon black;
[0167] wherein the colored polyimide film thickness is from 8 to
152 microns;
[0168] wherein the colored polyimide film has an optical density of
at least 1.4 as measured by measured with a Macbeth TD904 optical
densitometer; and wherein the carbon black is selected from the
group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0169] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0170] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine;
[0171] ii) 5 to 25 weight percent of pigment;
[0172] iii) 0.5 to 1 weight percent carbon black;
[0173] wherein the colored polyimide film thickness is from 8 to
152 microns; wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer; and wherein the carbon black is
selected from the group consisting of: a carbon black having a
volatile content greater than or equal to 13%, a furnace black, a
channel black and mixtures thereof.
[0174] In some embodiments, the colored polyimide film
comprises:
[0175] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0176] ii) 5 to 25 weight percent of pigment;
[0177] iii) 0.05 to 2 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0178] In some embodiments, the colored polyimide film
comprises:
[0179] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0180] ii) 5 to 25 weight percent of pigment;
[0181] iii) 0.1 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0182] In some embodiments, the colored polyimide film
comprises:
[0183] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0184] ii) 5 to 25 weight percent of pigment;
[0185] iii) 0.5 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0186] In another embodiment, the colored polyimide film
comprises:
[0187] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0188] ii) 5 to 25 weight percent of pigment;
[0189] iii) 0.5 to 1 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.8 as measured by measured with a Macbeth
TD904 optical densitometer.
[0190] In another embodiment, the colored polyimide film
comprises:
[0191] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0192] ii) 5 to 25 weight percent of pigment;
[0193] iii) 0.1 to 2 weight percent carbon black;
[0194] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
and
wherein the colored polyimide film thickness is from 8 to 152
microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0195] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0196] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0197] ii) 5 to 25 weight percent of pigment;
[0198] iii) 0.05 to 2 weight percent carbon black;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0199] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0200] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0201] ii) 5 to 25 weight percent of pigment;
[0202] iii) 0.05 to 2 weight percent carbon black;
[0203] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0204] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0205] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0206] ii) 5 to 25 weight percent of pigment;
[0207] iii) 0.1 to 1 weight percent carbon black;
[0208] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0209] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0210] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0211] ii) 5 to 25 weight percent of pigment;
[0212] iii) 0.5 to 1 weight percent carbon black;
[0213] iv) 10 to 25 weight percent of a filler selected from the
group consisting of thermally conductive fillers, dielectric
fillers, electrically conductive fillers and mixtures thereof;
wherein the colored polyimide film thickness is from 8 to 152
microns; wherein the colored polyimide film has an optical density
of at least 1.4 as measured by measured with a Macbeth TD904
optical densitometer; and wherein the carbon black is selected from
the group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0214] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0215] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0216] ii) 5 to 25 weight percent of pigment;
[0217] iii) 0.1 to 1 weight percent carbon black;
[0218] wherein the colored polyimide film thickness is from 8 to
152 microns; wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer; and wherein the carbon black is
selected from the group consisting of: a carbon black having a
volatile content greater than or equal to 13%, a furnace black, a
channel black and mixtures thereof.
[0219] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0220] i) 48 to 84 weight percent of a polyimide, the polyimide is
derived from least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide;
[0221] ii) 5 to 25 weight percent of pigment;
[0222] iii) 0.5 to 1 weight percent carbon black;
[0223] wherein the colored polyimide film thickness is from 8 to
152 microns; wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer; and wherein the carbon black is
selected from the group consisting of: a carbon black having a
volatile content greater than or equal to 13%, a furnace black, a
channel black and mixtures thereof.
[0224] In yet another embodiment, the colored polyimide film of the
present disclosure comprises:
[0225] i) 48 to 94 weight percent of a polyimide, the polyimide is
derived from at least one aromatic diamine and at least one
aromatic dianhydride;
[0226] ii) 5 to 25 weight percent of pigment;
[0227] iii) 0.1 to 1 weight percent carbon black; wherein the
carbon black is a carbon black having a volatile content greater
than or equal to 13%, a furnace black, a channel black or mixtures
thereof; wherein the colored polyimide film thickness is from 8 to
152 microns; and wherein the colored polyimide film has an optical
density of at least 1.4 as measured by measured with a Macbeth
TD904 optical densitometer.
[0228] The colored polyimide film, in accordance with any of the
above embodiments, wherein the pigment is selected from
diketopyrrolopyrrole pigment, Perylene Red or Ultramarine Blue.
[0229] In some embodiments, the colored polyimide film in
accordance with any of the above embodiments containing filler,
wherein the filler selected from the group consisting of: talc,
mica, silica, kaolin, titanium dioxide, boron nitride, barium
titanate, sepiolite, aluminum nitride and mixtures thereof. In some
embodiments, the colored polyimide film in accordance with any of
the above embodiments containing filler, wherein the filler is
boron nitride. In some embodiments, the colored polyimide film in
accordance with any of the above embodiments containing filler,
wherein the filler is barium titanate. In some embodiments, the
colored polyimide film in accordance with any of the above
embodiments containing filler, wherein the filler is sepiolite. In
some embodiments, the colored polyimide film in accordance with any
of the above embodiments containing filler, wherein the filler is
aluminum nitride. In some embodiments, the filler is a mixture of
any of the above mentioned fillers.
Preparation of the Colored Polyimide Film
[0230] The colored polyimide film can be prepared by any method
well known in the art for making a filled polyimide layer. In some
embodiments, the colored polyimide film can be prepared by thermal
conversion. In some embodiments, the colored polyimide film can be
prepared by chemical conversion. The carbon black can be
incorporated by any method known in the art for making filled
polyimide films, such as but not limited to, preparing a slurry of
carbon black and mixing the carbon black slurry with a pigment
slurry and a polyamic acid solution in a high shear mixer or
directly adding carbon black to a high shear mixer containing a
pigment and polyamic acid solution.
[0231] In one embodiment, a carbon black slurry and a pigment
slurry are prepared. The slurries may or may not be milled using a
ball mill to reach a desired particle size. The slurries may or may
not be filtered to remove any residual large particles. The pigment
(or pigment slurry) can be added to the polyamic acid before, at
the same time or after carbon black (or carbon black slurry). A
polyamic acid solution can be made by methods well known in the
art. In one such embodiment, the polyamic acid is made by
dissolving approximately equimolar amounts of a dianhydride and a
diamine in a solvent and agitating the resulting solution under
controlled temperature conditions until polymerization of the
dianhydride and the diamine is completed. Typically a slight excess
of one of the monomers (usually diamine) is used to initially
control the molecular weight and viscosity which can then be
increased later via small additional amounts of the deficient
monomer. The polyamic acid solution may or may not be filtered. The
polyamic acid solution is mixed in a high shear mixer with the
carbon black slurry and the pigment slurry. When a polyamic acid
solution is made with a slight excess of diamine, additional
dianhydride solution may or may not be added to increase the
viscosity of the mixture to the desired level for film casting. In
some embodiments, the carbon black is incorporated in to a colored
polyimide composition. The colored polyimide composition comprises
polyimide precursor material capable of conversion to a polyimide
and a pigment.
[0232] In some embodiments, the mixture of carbon black slurry,
pigment slurry and polyamic acid solution (casting solution) is
cast into a film on a sheet of Mylar.RTM. (polyethylene
terephthalate) using a stainless steel rod. The Mylar.RTM. sheet
containing the wet cast film is immersed in a chemical conversion
bath consisting of consisting of a catalyst, dehydrating agent or
both to form a gel film. The resulting gel film is peeled from the
Mylar.RTM. sheet and pressed onto a pin frame and allowed to air
dry until enough residual solvent has evaporated that the film
visually appears dry, approximately 5 minutes. The gel film is
cured in an oven set at 120.degree. C. and ramped up to 320.degree.
C. over 45 minutes. After the initial curing either the temperature
is increased to 400.degree. C. and held at that temperature for
approximately 5 more minutes or the film is placed in another oven
at 400.degree. C. for 5 minutes
[0233] The chemical conversion bath consists of an anhydride
(dehydrating agent), a tertiary amine (catalyst) or both, with or
without a diluting solvent. In either case, a gel film is formed
and the percent conversion of amic acid groups to imide groups in
the gel film depends on contact time and temperature but is usually
about 10 to 75 percent complete. For curing to a solids level
greater than 98% (greater than 98% imidized), the gel film
typically must be dried at elevated temperature (from about
200.degree. C., up to about 550.degree. C.), which will tend to
drive the imidization to completion. In some embodiments, the use
of both a dehydrating agent and a catalyst is preferred for
facilitating the formation of a gel film and achieve desired
conversion rates.
[0234] In another embodiment, the casting solution is mixed with
conversion chemicals. In some embodiments, an anhydride
(dehydrating agent) or a tertiary amine (catalyst) or both are
used. Then the casting solution is cast or extruded onto a heated
conversion surface or substrate such as a belt or drum. In some
embodiments the mixture is cooled below 0.degree. C. and mixed with
conversion chemicals prior to casting onto a heated rotating drum
or belt in order to produce a partially imidized gel film. The gel
film may be stripped from the drum or belt, placed on a tenter
frame, and cured in an oven, using convective and radiant heat to
remove solvent and complete the imizidation to greater than 98%
solids level.
[0235] The gel film tends to be self-supporting in spite of its
high solvent content. Typically, the gel film is subsequently dried
to remove the water, residual solvent, and remaining conversion
chemicals, and in the process the polyamic acid is essentially
completely converted to polyimide (i.e., greater than 98%
imidized). The drying can be conducted at relatively mild
conditions without complete conversion of polyamic acid to
polyimide at that time, or the drying and conversion can be
conducted at the same time using higher temperatures, generally
200.degree. C. to 550.degree. C. Less heat and time are required
for thin films than for thicker films.
[0236] Because the gel has so much liquid that must be removed
during the drying and converting steps, the gel generally must be
restrained during drying to avoid undesired shrinkage in fact, in
some embodiments, may be stretched by as much as 150 percent of its
initial dimension. In film manufacture, stretching can be in either
the longitudinal direction or the transverse direction or both. If
desired, restraint can also be adjusted to permit some limited
degree of shrinkage. In continuous production, the base film can be
held at the edges, such as in a tenter frame, using tenter clips or
pins for restraint.
[0237] In one embodiment, the anhydride (dehydrating agent), is
acetic anhydride, which is often used in molar excess relative to
the amount of amic acid (amide acid) groups in the polyamic acid,
typically about 1.2 to 2.4 moles per equivalent of polyamic acid.
In one embodiment, a comparable amount of tertiary amine (catalyst)
is used. Alternatives to acetic anhydride as the anhydride
(dehydrating agent) I include: i. other aliphatic anhydrides, such
as, propionic, butyric, valeric, and mixtures thereof; ii.
anhydrides of aromatic monocarboxylic acids; iii. Mixtures of
aliphatic and aromatic anhydrides; iv. carbodimides; and v.
aliphatic ketenes (ketenes may be regarded as anhydrides of
carboxylic acids derived from drastic dehydration of the
acids).
[0238] In one embodiment, the tertiary amine (catalyst) is pyridine
or beta-picoline is typically used in amounts similar to the moles
of anhydride (dehydrating agent). Lower or higher amounts may be
used depending on the desired conversion rate and the catalyst
used. Tertiary amines having approximately the same activity as the
pyridine, and beta-picoline may also be used. These include alpha
picoline; 3,4-lutidine; 3,5-lutidine; 4-methyl pyridine;
4-isopropyl pyridine; N,N-dimethylbenzyl amine; isoquinoline;
4-benzyl pyridine, N,N-dimethyldodecyl amine, triethyl amine, and
the like. A variety of other catalysts for imidization are known in
the art, such as imidazoles, and may be useful in accordance with
the present disclosure. In some embodiments, 50% acetic anhydride
and 50% beta-picoline by volume are used.
[0239] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating carbon black in
to a colored polyimide composition to obtain a colored polyimide
film comprising:
[0240] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0241] ii) 5 to 25 weight percent pigment;
[0242] iii) between and including any two of the following: 0.05,
0.1, 0.5 and 2 weight percent carbon black; and
wherein the optical density of the colored polyimide film is
increased by at least 15 percent compared to a colored polyimide
film incorporating a non-carbon black opacifying agent at the same
weight percent.
[0243] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating from 0.05 to 2
weight percent carbon black in to a colored polyimide composition
to obtain a colored polyimide film comprising:
[0244] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0245] ii) 5 to 25 weight percent pigment;
[0246] iii) 0.05 to 2 weight percent carbon black; and
wherein the optical density of the colored polyimide film is
increased by at least 15 percent compared to a colored polyimide
film incorporating a non-carbon black opacifying agent at the same
weight percent.
[0247] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating, between and
including any two of the following 0.05, 0.1, 0.5, 1 and 2 weight
percent, carbon black in to a colored polyimide composition to
obtain a colored polyimide film comprising:
[0248] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0249] ii) 5 to 25 weight percent pigment;
[0250] iii) 0.05 to 2 weight percent carbon black; and
wherein the optical density of the colored polyimide film is
increased by at least 10, 15, 20, 30, 40, 50 or 52 compared to a
colored polyimide film incorporating a non-carbon black opacifying
agent at the same weight percent.
[0251] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating from 0.05 to 2
weight percent carbon black in to a colored polyimide composition
to obtain a colored polyimide film comprising:
[0252] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0253] ii) 5 to 25 weight percent pigment;
[0254] iii) 0.1 to 1 weight percent carbon black; and
wherein the optical density of the colored polyimide film is
increased by at least 15 percent compared to a colored polyimide
film incorporating a non-carbon black opacifying agent at the same
weight percent.
[0255] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating from 0.05 to 2
weight percent carbon black in to a colored polyimide composition
to obtain a colored polyimide film comprising:
[0256] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0257] ii) 5 to 25 weight percent pigment;
[0258] iii) 0.5 to 1 weight percent carbon black; and
wherein the optical density of the colored polyimide film is
increased by at least 15 percent compared to a colored polyimide
film incorporating a non-carbon black opacifying agent at the same
weight percent.
[0259] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating carbon black in
to a colored polyimide composition to obtain a colored polyimide
film comprising:
[0260] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0261] ii) 5 to 25 weight percent pigment;
[0262] iii) 0.05 to 2 weight percent carbon black; and
wherein the optical density of the colored polyimide film is
increased by at least 15 percent compared to a colored polyimide
film incorporating a non-carbon black opacifying agent at the same
weight percent; and wherein the carbon black is selected from the
group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0263] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating from 0.05 to 2
weight percent carbon black in to a colored polyimide composition
to obtain a colored polyimide film comprising:
[0264] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0265] ii) 5 to 25 weight percent pigment;
[0266] iii) 0.05 to 2 weight percent carbon black; and
wherein the optical density of the colored polyimide film is
increased by at least 15 percent compared to a colored polyimide
film incorporating a non-carbon black opacifying agent at the same
weight percent; and wherein the carbon black is selected from the
group consisting of: a carbon black having a volatile content
greater than or equal to 13%, a furnace black, a channel black and
mixtures thereof.
[0267] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating from 0.05 to 2
weight percent carbon black in to a colored polyimide composition
to obtain a colored polyimide film comprising:
[0268] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0269] ii) 5 to 25 weight percent pigment;
[0270] iii) 0.05 to 2 weight percent carbon black; and
[0271] wherein the optical density of the colored polyimide film is
increased by at least 15 percent compared to a colored polyimide
film incorporating a non-carbon black opacifying agent at the same
weight percent; and wherein the colored polyimide film additionally
comprises from 10 to 25 weight percent of a filler selected from
the group consisting of: talc, mica, silica, kaolin, titanium
dioxide, boron nitride, barium titanate, sepiolite, aluminum
nitride or mixtures thereof.
[0272] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating carbon black in
to a colored polyimide composition to obtain a colored polyimide
film comprising:
[0273] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0274] ii) 5 to 25 weight percent pigment;
[0275] iii) 0.05 to 2 weight percent carbon black; and
[0276] wherein the optical density of the colored polyimide film is
increased by at least 15 percent compared to a colored polyimide
film incorporating a non-carbon black opacifying agent at the same
weight percent; wherein the carbon black is selected from the group
consisting of: a carbon black having a volatile content greater
than or equal to 13%, a furnace black, a channel black and mixtures
thereof; and wherein the colored polyimide film additionally
comprises from 10 to 25 weight percent of a filler selected from
the group consisting of: talc, mica, silica, kaolin, titanium
dioxide, boron nitride, barium titanate, sepiolite, aluminum
nitride or mixtures thereof.
[0277] Another embodiment of the present disclosure is a method of
increasing optical density comprising incorporating from 0.05 to 2
weight percent carbon black in to a colored polyimide composition
to obtain a colored polyimide film comprising:
[0278] i) 48 to 94 weight percent of a polyimide derived from at
least one aromatic diamine and at least one aromatic
dianhydride
[0279] ii) 5 to 25 weight percent pigment;
[0280] iii) 0.05 to 2 weight percent carbon black; and
[0281] wherein the optical density of the colored polyimide film is
increased by at least 15 percent compared to a colored polyimide
film incorporating a non-carbon black opacifying agent at the same
weight percent; wherein the carbon black is selected from the group
consisting of: a carbon black having a volatile content greater
than or equal to 13%, a furnace black, a channel black and mixtures
thereof; and wherein the colored polyimide film additionally
comprises from 10 to 25 weight percent of a filler selected from
the group consisting of: talc, mica, silica, kaolin, titanium
dioxide, boron nitride, barium titanate, sepiolite, aluminum
nitride or mixtures thereof.
[0282] Another embodiment of the present disclosure is a method of
increasing optical density, the method comprising:
[0283] incorporating a carbon black in to a colored polyimide
composition;
[0284] imidizing to obtain a colored polyimide film with at least a
15 percent increase in optical density compared to colored
polyimide composition with a non-carbon black opacifying agent
present in the same amount; and wherein the colored polyimide film
comprises: [0285] i) 48 to 94 weight percent of a polyimide derived
from at least one aromatic diamine and at least one aromatic
dianhydride; and [0286] ii) 5 to 25 weight percent pigment; [0287]
iii) 0.05 to 2 weight percent carbon black.
[0288] Another embodiment of the present disclosure is a method of
increasing optical density, the method comprising:
[0289] incorporating a carbon black in to a colored polyimide
composition;
[0290] imidizing to obtain a colored polyimide film with at least a
15 percent increase in optical density compared to colored
polyimide composition with a non-carbon black opacifying agent
present in the same amount; and wherein the colored polyimide film
comprises: [0291] i) 48 to 94 weight percent of a polyimide derived
from at least one aromatic diamine and at least one aromatic
dianhydride; and [0292] ii) 5 to 25 weight percent pigment; [0293]
iii) between and including any two of the following: 0.05, 0.1, 0.5
and 2 weight percent carbon black.
[0294] Another embodiment of the present disclosure is a method of
increasing optical density, the method comprising:
[0295] incorporating a carbon black in an amount from 0.05 to 2
weight percent in to a colored polyimide composition;
[0296] imidizing to obtain a colored polyimide film with at least a
15 percent increase in optical density compared to colored
polyimide composition with a non-carbon black opacifying agent
present in the same amount; and wherein the colored polyimide film
comprises: [0297] i) 48 to 94 weight percent of a polyimide derived
from at least one aromatic diamine and at least one aromatic
dianhydride; and [0298] ii) 5 to 25 weight percent pigment; [0299]
iii) 0.05 to 2 weight percent carbon black.
[0300] Another embodiment of the present disclosure is a method of
increasing optical density, the method comprising:
[0301] incorporating a carbon black in an amount from 0.1 to 1
weight percent in to a colored polyimide composition;
[0302] imidizing to obtain a colored polyimide film with at least a
15 percent increase in optical density compared to colored
polyimide composition with a non-carbon black opacifying agent
present in the same amount; and wherein the colored polyimide film
comprises: [0303] i) 48 to 94 weight percent of a polyimide derived
from at least one aromatic diamine and at least one aromatic
dianhydride; and [0304] ii) 5 to 25 weight percent pigment; [0305]
iii) 0.1 to 1 weight percent carbon black.
[0306] Another embodiment of the present disclosure is a method of
increasing optical density, the method comprising:
[0307] incorporating a carbon black in an amount from 0.5 to 1
weight percent in to a colored polyimide composition;
[0308] imidizing to obtain a colored polyimide film with at least a
15 percent increase in optical density compared to colored
polyimide composition with a non-carbon black opacifying agent
present in the same amount; and wherein the colored polyimide film
comprises: [0309] i) 48 to 94 weight percent of a polyimide derived
from at least one aromatic diamine and at least one aromatic
dianhydride; and [0310] ii) 5 to 25 weight percent pigment; [0311]
iii) 0.5 to 1 weight percent carbon black.
[0312] Another embodiment of the present disclosure is a method of
increasing optical density of a colored polyimide film, the method
comprising: incorporating in to a colored polyimide composition a
carbon black in an amount sufficient to achieve at least a 15
percent increase in optical density compared to colored polyimide
composition with a non-carbon black opacifying agent present in the
same amount.
[0313] Another embodiment of the present disclosure is the method
in accordance with any of the above embodiments wherein the carbon
black is selected from the group consisting of: a carbon black
having a volatile content greater than or equal to 13%, a furnace
black, a channel black and mixtures thereof.
[0314] Another embodiment of the present disclosure is the method
in accordance with any of the above embodiments wherein the
polyimide is derived from pyromellitic dianhydride and
4,4'-oxydianiline.
[0315] Another embodiment of the present disclosure is the method
in accordance with any of the above embodiments wherein the
polyimide is derived from pyromellitic dianhydride,
3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydianiline
and paraphenylene diamine.
[0316] Another embodiment of the present disclosure is the method
in accordance with any of the above embodiments wherein the
polyimide is derived from at least 45 mole percent of
3,3',4,4'-biphenyltetracarboxylic dianhydride, based on a total
dianhydride content of the polyimide, and at least 50 mole percent
of 2,2'-bis(trifluoromethyl) benzidine based on a total diamine
content of the polyimide.
[0317] Another embodiment of the present disclosure is the method
in accordance with any of the above embodiments wherein the
polyimide is derived from pyromellitic dianhydride,
4,4'-oxydianiline and paraphenylene diamine.
[0318] Another embodiment of the present disclosure is the method
in accordance with any of the above embodiments wherein the colored
polyimide film, or the colored polyimide composition, additionally
comprises from 10 to 25 weight percent of a filler selected from
the group consisting of: talc, mica, silica, kaolin, titanium
dioxide, boron nitride, barium titanate, sepiolite, aluminum
nitride or mixtures thereof. Another embodiment of the present
disclosure is the method in accordance with any of the above
embodiments wherein the colored polyimide film, or the colored
polyimide composition, additionally comprises between and including
any two of the following: 10, 12, 14, 16, 20, 22, 24 and 25 weight
percent of a filler selected from the group consisting of: talc,
mica, silica, kaolin, titanium dioxide, boron nitride, barium
titanate, sepiolite, aluminum nitride or mixtures thereof.
[0319] The colored polyimide film, in accordance with any of the
above embodiments, wherein the pigment is selected from
diketopyrrolopyrrole pigment, Perylene Red or Ultramarine Blue.
[0320] In some embodiments, the colored polyimide film in
accordance with any of the above embodiments containing filler,
wherein the filler selected from the group consisting of: talc,
mica, silica, kaolin, titanium dioxide, boron nitride, barium
titanate, sepiolite, aluminum nitride and mixtures thereof. In some
embodiments, the colored polyimide film in accordance with any of
the above embodiments containing filler, wherein the filler is
boron nitride. In some embodiments, the colored polyimide film in
accordance with any of the above embodiments containing filler,
wherein the filler is barium titanate. In some embodiments, the
colored polyimide film in accordance with any of the above
embodiments containing filler, wherein the filler is sepiolite. In
some embodiments, the colored polyimide film in accordance with any
of the above embodiments containing filler, wherein the filler is
aluminum nitride. In some embodiments, the filler is a mixture of
any of the above mentioned fillers.
[0321] In some embodiments, the carbon black incorporated is from
0.1 to 1 weight percent and the colored polyimide film comprises
from 0.1 to 1 weight percent carbon black.
[0322] In some embodiments, the carbon black incorporated is from
0.5 to 1 weight percent and the colored polyimide film comprises
from 0.5 to 1 weight percent carbon black.
EXAMPLES
[0323] The invention will be further described in the following
examples, which is not intended to limit the scope of the invention
described in the claims.
[0324] Optical density was measured with a Macbeth TD904 optical
densitometer. The averages of 3 individual measurements were
recorded. All optical density measurements were taken within an
area of film measuring approximately 15 microns thick. Film
thickness was verified by multiple measurements across the region
in question using a Heidenhain point thickness gage measurement
instrument with a motorized Certo probe and a steel pin-type
contact tip.
Example 1
[0325] Example 1 demonstrates when 0.1 wt % carbon black is used as
the opacifying agent, the optical density (1.86) was greater
compared to the optical density of a colored polyimide film having
the same amount of red pigment but using 1 wt % TiO2 (1.78).
[0326] A carbon black slurry was prepared, consisting of 80 wt %
DMAC, 10 wt % polyamic acid solution (20.6 wt % polyamic acid
solids in DMAC), and 10 wt % carbon black powder (Special Black 4,
from Evonik Degussa). The ingredients were thoroughly mixed in a
rotor stator, high-speed dispersion mill. The carbon black slurry
was then processed in a ball mill to disperse any large
agglomerates and to achieve the desired particle size. The median
particle size of the carbon black slurry was 0.3 microns. Median
particle size was measured using a Horiba LA-930 particle size
analyzer. Horiba, Instruments, Inc., Irvine Calif. DMAC
(dimethylacetamide) was used as the carrier fluid.
[0327] A red pigment slurry was prepared, consisting of 75 wt %
DMAC, and 25 wt % red pigment (Paliogen Red L 3880 HD, from BASF).
The red pigment slurry was mixed using a Thinky ARE-250 planetary
centrifugal mixer.
[0328] 0.29 g of the carbon black slurry, 5.72 g of the red pigment
slurry and 144.00 g PMDA/4,4'ODA polyamic acid solution (20.6%
polyamic acid solids in DMAC) were mixed in a Thinky ARE-250, and
also degassed in the same equipment. The mixture was manually cast
using a stainless steel rod onto a Mylar.RTM. polyethylene
terephthalate sheet attached to a glass plate. The Mylar.RTM.
polyethylene terephthalate sheet containing the wet cast film was
immersed in a bath consisting of a 50/50 mixture of 3 picoline and
acetic anhydride. The bath was gently agitated for a period of 3 to
4 minutes in order to effect imidization and gellation of the film.
The resulting gel film was peeled from the Mylar.RTM. polyethylene
terephthalate sheet and pressed onto a pin frame and allowed to air
dry until enough residual solvent has evaporated that the film
visually appears dry, approximately 5 minutes. The gel film was
then cured in a Blue M high temperature electric oven set at
120.degree. C. and ramped up to 320.degree. C. over 45 minutes.
After the initial curing, the film was placed in another Blue M
oven at 400.degree. C. for 5 minutes. The resulting film contained
5 wt % red pigment, and 0.1 wt % carbon black.
[0329] Optical density verses non-carbon black opacifying agent
loading level is plotted in FIG. 1. Results are shown in Table
1.
Example 2
[0330] Example 2 demonstrates when using 0.5 wt % carbon black, the
optical density (2.21):
[0331] is approximately 21% greater compared to the optical density
of a colored polyimide film having the same amount of red pigment
but using 0.5 wt % paliogen black (1.83), and
[0332] is greater compared to the optical density of a colored
polyimide film having the same amount of red pigment but using 1 wt
% TiO2 (1.78), and
[0333] is greater compared to the optical density of a colored
polyimide film having the same amount of red pigment but using 10
wt % TiO2 (2.12).
[0334] 1.43 g of the carbon black slurry (prepared in Example 1),
5.70 g of the red pigment slurry (prepared in Example 1), and
142.88 g PMDA/4,4'ODA polyamic acid solution (20.6% polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The resulting film contained 5 wt % red pigment, and 0.5
wt % carbon black.
[0335] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Example 3
[0336] Example 3 demonstrates when using 1 wt % carbon black, the
optical density (2.70) is approximately 52% greater compared to the
optical density of a colored polyimide film having the same amount
of red pigment but using 1 wt % TiO2 (1.78), and is approximately
19% greater compared to the optical density of a colored polyimide
film having the same amount of red pigment but using 10 wt % TiO2
(2.12).
[0337] 2.94 g of the carbon black slurry (prepared in Example 1),
5.68 g of the red pigment slurry (prepared in Example 1), and
141.48 g PMDA/4,4'ODA polyamic acid solution (20.6% polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The resulting film contained 5 wt % red pigment, and 1
wt % carbon black.
[0338] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Comparative Example 1
[0339] 5.72 g red pigment slurry (prepared in Example 1) and 144.28
g PMDA/4,4'ODA polyamic acid solution (20.6 wt % polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The final cured film contained 5 wt % red pigment.
[0340] Results are shown in Table 1.
Example 4
[0341] Example 4 demonstrates when using 0.1 wt % carbon black, the
optical density (2.70) is increased approximately 8% compared to
the optical density of a colored polyimide film having the same
amount of red pigment but does not contain an opacifying agent
(2.50).
[0342] 0.29 g of the carbon black slurry (prepared in Example 1),
17.58 g of the red pigment slurry (prepared in Example 1), and
132.12 g PMDA/4,4'ODA polyamic acid solution (20.6% polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The resulting film contained 15 wt % red pigment, and
0.1 wt % carbon black.
[0343] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Example 5
[0344] Example 5 demonstrates when using 0.5 wt % carbon black, the
optical density (3.25) is increased approximately 30% compared to
the optical density of a colored polyimide film having the same
amount of red pigment but does not contain an opacifying agent
(2.50).
[0345] 1.46 g of the carbon black slurry (prepared in Example 1),
17.53 g of the red pigment slurry (prepared in Example 1), and
131.01 g PMDA/4,4'ODA polyamic acid solution (20.6% polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The resulting film contained 15 wt % red pigment, and
0.5 wt % carbon black.
[0346] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Example 6
[0347] Example 6 demonstrates when using 1 wt % carbon black, the
optical density (3.67) is increased approximately 47% compared to
the optical density of a colored polyimide film having the same
amount of red pigment but does not contain an opacifying agent
(2.50).
[0348] 2.91 g of the carbon black slurry (prepared in Example 1),
17.47 g of the red pigment slurry (prepared in Example 1), and
129.62 g PMDA/4,4'ODA polyamic acid solution (20.6% polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The resulting film contained 15 wt % red pigment, and 1
wt % carbon black.
[0349] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Comparative Example 2
[0350] Comparative Example 2 demonstrates that when the amount of
red pigment is increase from 5 wt % to 15 wt % the optical density
(2.50) is still lower compared to the optical density when the
amount of red pigment is 5 wt % and 1 wt % of carbon black is used
(2.7).
[0351] 17.60 g of the red pigment slurry (prepared in Example 1),
and 132.40 g PMDA/4,4'ODA polyamic acid solution (20.6% polyamic
acid solids in DMAC) were mixed, cast, and cured in the same
process as Example 1. The resulting film contained 15 wt % red
pigment.
[0352] Results are shown in Table 1.
Comparative Example 3
[0353] Comparative Example 3 demonstrates that when 1 wt % of
titanium dioxide is used as the opacifying agent, the optical
density (1.78):
[0354] is significantly lower compared to a colored polyimide film
having the same amount of red pigment and 1 wt % carbon black
(2.70), and
[0355] is lower compared to a colored polyimide film with 0.5 wt %
carbon black (2.21), and
[0356] is lower compared to a colored polyimide film with 0.1 wt %
carbon black (1.86).
[0357] Titanium Dioxide slurry was prepared, consisting of 70.15 wt
% DMAC, 25 wt % titanium dioxide (Ti-Pure R706, from DuPont), and
4.85 wt % PMDA/4,4'ODA polyamic acid solution (20.6% polyamic acid
solids in DMAC). The titanium dioxide slurry was mixed using a
Thinky ARE-250 planetary centrifugal mixer.
[0358] 1.15 g of the titanium dioxide slurry, 5.74 g of the red
pigment slurry (prepared in Example 1), and 143.12 g PMDA/4,4'ODA
polyamic acid solution (20.6% polyamic acid solids in DMAC) were
mixed, cast, and cured in the same process as Example 1. The
resulting film contained 5 wt % red pigment, and 1 wt %
TiO.sub.2.
[0359] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Comparative Example 4
[0360] Comparative Example 4 demonstrates that a colored polyimide
film containing 10 wt % titanium dioxide has a lower optical
density (2.12) compared to a colored polyimide film having the same
amount of red pigment and 1 wt % carbon black (2.70) and has a
lower optical density compared to a colored polyimide film having
the same amount of red pigment and 0.5 wt % carbon black
(2.21).
[0361] 11.78 g of the titanium dioxide slurry (prepared in
Comparative Example 3), 5.89 g of the red pigment slurry (prepared
in Example 1), and 132.34 g PMDA/4,4'ODA polyamic acid solution
(20.6% polyamic acid solids in DMAC) were mixed, cast, and cured in
the same process as Example 1. The resulting film contained 5 wt %
red pigment, and 10 wt % TiO.sub.2.
[0362] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Comparative Example 5
[0363] Comparative Example 5 demonstrates that when 0.5 wt % of
paliogen black (an organic black pigment) is used as the opacifying
agent, the optical density (1.83) is significantly lower compared
to a colored polyimide film having the same amount of red pigment
and 0.5 wt % carbon black (2.21) and has a lower optical density
compared to a colored polyimide film having the same amount of red
pigment and 0.1 wt % carbon black (1.86).
[0364] Black pigment slurry was prepared, consisting of 70.15 wt %
DMAC, 25 wt % black pigment (Paliogen Black L 0086, from BASF), and
4.85 wt % PMDA/4,4'ODA polyamic acid solution (20.6% polyamic acid
solids in DMAC). The black pigment slurry was mixed using a Thinky
ARE-250 planetary centrifugal mixer.
[0365] 0.57 g of the black pigment slurry, 5.73 g of the red
pigment slurry (prepared in Example 1), and 143.70 g PMDA/4,4'ODA
polyamic acid solution (20.6% polyamic acid solids in DMAC) were
mixed, cast, and cured in the same process as Example 1. The
resulting film contained 5 wt % red pigment, and 0.5 wt % black
pigment.
[0366] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Comparative Example 6
[0367] Comparative Example 6 demonstrates that when 5 wt % paliogen
black is used as the opacifying agent, the optical density (2.59)
is still lower than a colored polyimide film having the same amount
of red pigment and 1 wt % carbon black (2.70).
[0368] 5.80 g of the black pigment slurry (prepared in Comparative
Example 5), 5.80 g of the red pigment slurry (prepared in Example
1), and 138.40 g PMDA/4,4'ODA polyamic acid solution (20.6%
polyamic acid solids in DMAC) were mixed, cast, and cured in the
same process as Example 1. The resulting film contained 5 wt % red
pigment, and 5 wt % black pigment.
[0369] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Example 7
[0370] Example 7 demonstrates that when 0.1 wt % of carbon black is
used the optical density (1.40) is increased 27% compared to
colored polyimide films having the same amount of blue pigment but
does not contain an opacifying agent (1.10).
[0371] Blue pigment slurry was prepared, consisting of 65.15 wt %
DMAC, 30 wt % blue pigment (Ultramarine Blue FP-40, from Nubiola),
and 4.85 wt % PMDA/4,4'ODA polyamic acid solution (20.6% polyamic
acid solids in DMAC). The blue pigment slurry was mixed using a
Thinky ARE-250 planetary centrifugal mixer.
[0372] 26.15 g of the blue pigment slurry, 0.31 g of the carbon
black slurry (prepared in Example 1), and 123.54 g PMDA/4,4'ODA
polyamic acid solution (20.6% polyamic acid solids in DMAC) were
mixed, cast, and cured in the same process as Example 1. The
resulting film contained 25 wt % blue pigment, and 0.1% carbon
black.
[0373] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Example 8
[0374] Example 8 demonstrates that when 0.5 wt % of carbon black is
used the optical density (1.86) is increased 69% compared to a
colored polyimide film having the same amount of blue pigment but
does not contain an opacifying agent (1.10).
[0375] 26.07 g of the blue pigment slurry (prepared in Example 7),
1.56 g of the carbon black slurry (prepared in Example 1), and
122.37 g PMDA/4,4'ODA polyamic acid solution (20.6% polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The resulting film contained 25 wt % blue pigment, and
0.5% carbon black.
[0376] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Comparative Example 7
[0377] 26.17 g of the blue pigment slurry (prepared in Example 7),
and 123.83 g PMDA/4,4'ODA polyamic acid solution (20.6% polyamic
acid solids in DMAC) were mixed, cast, and cured in the same
process as Example 1. The resulting film contained 25 wt % blue
pigment.
[0378] Results are shown in Table 1.
Comparative Example 8
[0379] Comparative Example 8 demonstrates when 10 wt % TiO2 is
used, the optical density (1.56) is lower compared to a colored
polyimide film having the same amount of blue pigment but
containing 0.5 wt % carbon black (1.86).
[0380] 12.97 g of the titanium dioxide slurry (prepared in
Comparative Example 3), 27.02 g of the blue pigment slurry
(prepared in Example 7), and 110.01 g PMDA/4,4'ODA polyamic acid
(20.6% polyamic acid solids in DMAC) were mixed, cast, and cured in
the same process as Example 1. The resulting film contained 25 wt %
blue pigment, and 10 wt % TiO.sub.2.
[0381] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Comparative Example 9
[0382] Comparative Example 9 demonstrates that if the amount of
paliogen black is extrapolated in FIG. 1 to the same amount of
carbon black in examples 7 or 8 (0.1 and 0.5 wt % respectively) the
optical density, when using paliogen black, would be much less
compared to using carbon black.
[0383] 6.38 g of the black pigment slurry (prepared in Comparative
Example 5), 26.59 g of the blue pigment slurry (prepared in Example
7), and 117.03 g PMDA/4,4'ODA polyamic acid (20.6% polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The resulting film contained 25 wt % blue pigment, and 5
wt % black pigment.
[0384] Optical density verses opacifying agent loading level is
plotted in FIG. 1. Results are shown in Table 1.
Example 9
[0385] Example 9 demonstrates when using 1 wt % carbon black, the
optical density (1.99) is approximately 20% greater compared to the
optical density of a colored polyimide film having the same amount
of blue pigment but using 1 wt % TiO2 (1.65), and is approximately
15% greater compared to the optical density of a colored polyimide
film having the same amount of blue pigment but using 1 wt %
paliogen black (1.72).
[0386] 25.97 g of the blue pigment slurry (prepared in Example 7),
3.12 g of the carbon black slurry (prepared in Example 1), and
120.91 g PMDA/4,4'ODA polyamic acid solution (20.6% polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The resulting film contained 25 wt % blue pigment, and 1
wt % carbon black.
[0387] Results are shown in Table 1.
Comparative Example 10
[0388] Comparative example 10 demonstrates when 1 wt % TiO2 is
used, the optical density (1.65) is lower compared to a colored
polyimide film having the same amount of blue pigment but
containing 1 wt % carbon black (1.99).
[0389] 1.26 g of the titanium dioxide slurry (prepared in
Comparative Example 3), 26.25 g of the blue pigment slurry
(prepared in Example 7), and 122.49 g PMDA/4,4'ODA polyamic acid
(20.6% polyamic acid solids in DMAC) were mixed, cast, and cured in
the same process as Example 1. The resulting film contained 25 wt %
blue pigment, and 1 wt % TiO.sub.2.
[0390] Results are shown in table 1.
Comparative Example 11
[0391] Comparative example 10 demonstrates when 1 wt % paliogen
black is used, the optical density (1.72) is lower compared to a
colored polyimide film having the same amount of blue pigment but
containing 1 wt % carbon black (1.99).
[0392] 1.26 g of the black pigment slurry (prepared in Comparative
Example 5), 26.25 g of the blue pigment slurry (prepared in Example
7), and 122.49 g PMDA/4,4'ODA polyamic acid (20.6% polyamic acid
solids in DMAC) were mixed, cast, and cured in the same process as
Example 1. The resulting film contained 25 wt % blue pigment, and 1
wt % paliogen black.
[0393] Results are shown in table 1.
TABLE-US-00001 TABLE 1 Example # Sample Composition Optical Density
1 5% Paliogen Red 0.1% Carbon Black 1.86 2 5% Paliogen Red 0.5%
Carbon Black 2.21 3 5% Paliogen Red 1% Carbon Black 2.70 Comp. 1 5%
Paliogen Red 1.70 4 15% Paliogen Red 0.1% Carbon Black 2.70 5 15%
Paliogen Red 0.5% Carbon Black 3.25 6 15% Paliogen Red 1% Carbon
Black 3.67 Comp. 2 15% Paliogen Red 2.50 Comp. 3 5% Paliogen Red 1%
TiO2 1.78 Comp. 4 5% Paliogen Red 10% TiO2 2.12 Comp. 5 5% Paliogen
Red 0.5% Paliogen Black 1.83 Comp. 6 5% Paliogen Red 5% Paliogen
Black 2.59 7 25% Nubiola Blue 0.1% Carbon Black 1.40 8 25% Nubiola
Blue 0.5% Carbon Black 1.88 Comp. 7 25% Nubiola Blue 1.10 Comp. 8
25% Nubiola Blue 10% TiO2 1.56 Comp. 9 25% Nubiola Blue 5% Paliogen
Black 3.16 9 25% Nubiola Blue 1% Carbon Black 1.99 Comp. 10 25%
Nubiola Blue 1% TiO2 1.65 Comp. 11 25% Nubiola Blue 1% Paliogen
Black 1.72
[0394] Note that not all of the activities described above in the
general description or the examples are required, that a portion of
a specific activity may not be required, and that further
activities may be performed in addition to those described. Still
further, the order in which each of the activities are listed are
not necessarily the order in which they must be performed. After
reading this specification, the ordinary artisan will be capable of
determining what activities can be used for their specific needs or
desires.
[0395] In the foregoing specification, the invention has been
described with reference to specific embodiments. However, one of
ordinary skill in the art appreciates that various modifications
and changes can be made without departing from the scope of the
invention as set forth in the claims below. All features disclosed
in this specification may be replaced by alternative features
serving the same, equivalent or similar purpose.
[0396] Accordingly, the specification and figures are to be
regarded in an illustrative rather than a restrictive sense and all
such modifications are intended to be included within the scope of
the invention.
* * * * *