U.S. patent application number 14/176309 was filed with the patent office on 2014-08-14 for surface modifier for polyimide resin and surface-modifying method for polyimide resin.
This patent application is currently assigned to SEIREN CO., LTD.. The applicant listed for this patent is SEIREN CO., LTD.. Invention is credited to Takuya ARITA, Akimitsu BAMBA, Hiroyuki HAYASHI, Kouichi KUGIMIYA.
Application Number | 20140227446 14/176309 |
Document ID | / |
Family ID | 51297613 |
Filed Date | 2014-08-14 |
United States Patent
Application |
20140227446 |
Kind Code |
A1 |
BAMBA; Akimitsu ; et
al. |
August 14, 2014 |
SURFACE MODIFIER FOR POLYIMIDE RESIN AND SURFACE-MODIFYING METHOD
FOR POLYIMIDE RESIN
Abstract
The present invention relates to a polyimide resin surface
modifier which modifies the surface of a polyimide resin to permit
easy absorption of metal ions, and a surface-modifying method for
polyimide resins using the same. The surface modifier contains an
alkali component, an organic solvent having hydroxy groups and a
boiling point of 120.degree. C. or higher, and a water content of
0-10% by weight. The surface-modifying method includes a printing
process wherein a predetermined pattern is printed on the surface
of a polyimide resin substrate using the polyimide resin surface
modifier, an organic solvent-removing process wherein an organic
solvent in the polyimide resin surface modifier pattern-printed on
the surface of said polyimide resin substrate is removed and a
water-treatment process wherein said polyimide resin surface
modifier after removing the organic solvent is brought into contact
with water.
Inventors: |
BAMBA; Akimitsu; (Fukui,
JP) ; ARITA; Takuya; (Fukui, JP) ; HAYASHI;
Hiroyuki; (Fukui, JP) ; KUGIMIYA; Kouichi;
(Fukui, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEIREN CO., LTD. |
Fukui |
|
JP |
|
|
Assignee: |
SEIREN CO., LTD.
Fukui
JP
|
Family ID: |
51297613 |
Appl. No.: |
14/176309 |
Filed: |
February 10, 2014 |
Current U.S.
Class: |
427/256 ;
252/182.14; 252/182.23; 524/376; 524/377 |
Current CPC
Class: |
G03F 7/00 20130101; B41J
11/0015 20130101; H05K 3/182 20130101; B41F 15/00 20130101 |
Class at
Publication: |
427/256 ;
252/182.23; 252/182.14; 524/376; 524/377 |
International
Class: |
H05K 3/38 20060101
H05K003/38 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 13, 2013 |
JP |
2013-025603 |
Feb 13, 2013 |
JP |
2013-025604 |
Claims
1. A polyimide resin surface modifier which contains an alkali
component and an organic solvent having hydroxy groups and a
boiling point of 120.degree. C. or higher, wherein the water
content is 0-10% by weight.
2. The polyimide resin surface modifier according to claim 1, which
further contains a water-soluble polymer compound.
3. The polyimide resin surface modifier according to claim 1,
wherein said alkali component is selected from the group consisting
of an alkali metal hydroxide and a quaternary ammonium
hydroxide.
4. The polyimide resin surface modifier according to claim 1,
wherein said organic solvent is an alcoholic compound.
5. The polyimide resin surface modifier according to claim 4,
wherein said alcoholic compound is selected from the group
consisting of hydrocarbon-type alcohols, alkylene glycols and
glycol ethers.
6. The polyimide resin surface modifier according to claim 2,
wherein said water-soluble polymer compound is selected from the
group consisting of polyvinyl pyrrolidone, polyvinyl alcohol and
carboxy methylcellulose.
7. A surface-modifying method for a polyimide resin which comprises
a printing process wherein a predetermined pattern is printed on
the surface of a polyimide resin substrate using a polyimide resin
surface modifier containing an alkali component and an organic
solvent having hydroxy groups and a boiling point of 120.degree. C.
or higher wherein the water content is 0-10% by weight, an organic
solvent-removing process wherein an organic solvent in the
polyimide resin surface modifier pattern-printed on the surface of
said polyimide resin substrate is removed and a water-treatment
process wherein said polyimide resin surface modifier after
removing the organic solvent is brought into contact with
water.
8. The surface-modifying method for a polyimide resin according to
claim 7, wherein said polyimide resin surface modifier further
contains a water-soluble polymer compound.
9. The surface-modifying method for a polyimide resin according to
claim 7, wherein said printing is carried out by a screen printing
method.
10. The surface-modifying method for a polyimide resin according to
claim 7, wherein said printing is carried out by an inkjet printing
method.
11. The polyimide resin surface modifier according to claim 2,
wherein said alkali component is selected from the group consisting
of an alkali metal hydroxide and a quaternary ammonium
hydroxide.
12. The polyimide resin surface modifier according to claim 2,
wherein said organic solvent is an alcoholic compound.
13. The polyimide resin surface modifier according to claim 12,
wherein said alcoholic compound is selected from the group
consisting of hydrocarbon-type alcohols, alkylene glycols and
glycol ethers.
14. The surface-modifying method for a polyimide resin according to
claim 8, wherein said printing is carried out by a screen printing
method.
15. The surface-modifying method for a polyimide resin according to
claim 8, wherein said printing is carried out by an inkjet printing
method.
Description
TECHNICAL FIELD
[0001] The present invention relates to a surface modifier for
polyimide resins for modifying the surface of a polyimide resin so
that metal ions can be adsorbed easily, and a surface-modifying
method for polyimide resins using the same.
BACKGROUND ART
[0002] In the field of electronic components, decorating items or
the like, resin materials with a metal film pattern formed thereon
have been used from many years ago. Typical examples thereof
include a flexible printed-wiring board wherein a metal film
circuit pattern is formed on the surface of a resin film.
[0003] Along with the miniaturization of electronic equipment, the
miniaturization of flexible printed-wiring boards has also been
developed and it has been required to form a finer circuit pattern.
At the same time, in addition, it has also been required to improve
the adhesiveness of the metal film to the resin film surface.
[0004] As a typical method for forming a circuit pattern, it has
been known a method wherein a metal film is formed on a whole
surface of a polyimide resin film by means of vapor deposition,
sputtering or laminating a copper foil using an adhesive, then the
metal film is exposed in pattern by a photolithography method,
being developed, and the unnecessary metal is removed by
etching.
[0005] However, this method has such problems as a low productivity
cause by the great mass of metal to be removed, heavy effects on
the environment caused by etching waste liquid and high cost of
equipment and material such as photomasks, exposure devices, and
photoresist.
[0006] Attention has been focused on a pattern printing technology
using a metal nano-ink. The metal nano-ink and/or paste can be
patterned on a substrate by an inkjet printing method or a screen
printing method, whereby a conductive pattern can be formed
directly thereon. However, the method also has such problems that
the cost of raw material is high and that a calcination process is
required after printing and therefore the substrate to be used is
restricted to be one of heat resistant. In addition, specific
resistance of the conductive pattern thus formed is higher compared
with that formed by plating, which may cause a problem from the
aspect of electric characteristics for applications for electronic
equipment.
[0007] As a means for solving the above problems, in recent years,
attention has been focused on a direct metallization method as
disclosed in Patent Documents 1, 2 and 3, in which an imide ring of
a polyimide resin film is opened by treating the surface of the
polyimide resin film with alkali, then metal salts are adsorbed to
the carboxyl group formed by opening the imide ring, and the metal
salts are reduced to deposit a metal film.
[0008] Patent Documents 4 and 5 disclose a method wherein an
alkaline ink is applied by an inkjet method selectively to a
polyimide resin substrate at the part for forming the inorganic
thin film to open the imide ring, then metal ions are adsorbed to
said part to form metal salts, and then the metal salts are reduced
to form an inorganic thin film pattern.
[0009] According to the method, it is not necessary to remove the
metal film of the unnecessary part by etching after forming a metal
film on the whole surface of the polyimide resin substrate.
PRIOR ART DOCUMENTS
Patent Document
[0010] Patent Document 1: Jpn. Pat. No. 3825790 [0011] Patent
Document 2: Jpn. Pat. Laid-Open Publication No. 2008-053682 [0012]
Patent Document 3: Jpn. Pat. Laid-Open Publication No. 2011-014801
[0013] Patent Document 4: Jpn. Pat. Laid-Open Publication No.
2005-029735 [0014] Patent Document 4: Jpn. Pat. Laid-Open
Publication No. 2005-045236
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0015] However, the methods disclosed in Patent Documents 1-3 also
require an etching process, similar to the conventional methods,
because a metal film is formed on the whole surface of the
substrate in advance and then the metal film is patterned.
[0016] By the etching process, the interfacial surface between the
patterned metal film and the resin substrate might be corroded to
form under-etch, which might cause deterioration of adhesion of
metal film and also might cause degradation of electromigration
resistance after forming a pattern plate since the metal film is
formed on the whole surface in advance. An influence of these
problems becomes high as the metal film pattern becomes fine.
[0017] There is a method wherein an alkaline aqueous solution is
applied in a pattern shape to form a metal film only on the
necessary part from the first. However, a strongly alkaline aqueous
solution capable of opening the imide ring would give a heavy
burden to a printer. For example, a photosensitive emulsion which
is used for a printing plate for screen printing would easily
suffer damage by a strongly alkaline agent, which might cause
deterioration of printing precision. In the inkjet method disclosed
in Patent Documents 4 and 5, using a strongly alkaline ink would
cause not only corrosion of a head body but also damage to a liquid
repellent polymer layer on the orifice plate of an inkjet head for
discharging ink and would cause a deterioration of ink discharging
performance.
[0018] In the case of using a solvent modifier containing organic
alkali in which alkali dissociation is suppressed for preventing
damage to a screen printing plate, alkali hydrolysis reaction on
the surface of a polyimide resin would not progress sufficiently,
and as a result, modification ability would be deteriorated which
would cause a low modification degree and/or would cause
modification ununiformity.
[0019] The problem to be solved by the present invention is to
provide a polyimide resin surface modifier having a sufficient
modification ability which can minimize damage to a printing plate
and/or a printer and can open imide rings on the surface of a
polyimide resin sufficiently, and to provide a surface-modifying
method for a polyimide resin using said polyimide resin surface
modifier.
Means for Solving the Problems
[0020] That is, the present invention provides a polyimide resin
surface modifier and a surface-modifying method for a polyimide
resin shown as follows:
(1) A polyimide resin surface modifier which contains an alkali
component and an organic solvent having hydroxy groups and a
boiling point of 120.degree. C. or higher, wherein the water
content is 0-10% by weight. (2) The polyimide resin surface
modifier according to (1), which further contains a water-soluble
polymer compound. (3) The polyimide resin surface modifier
according to (1) or (2), wherein said alkali component is selected
from the group consisting of an alkali metal hydroxide and a
quaternary ammonium hydroxide. (4) The polyimide resin surface
modifier according to (1) or (2), wherein said organic solvent is
an alcoholic compound. (5) The polyimide resin surface modifier
according to (4), wherein said alcoholic compound is selected from
the group consisting of hydrocarbon-type alcohols, alkylene glycols
and glycol ethers. (6) The polyimide resin surface modifier
according to (2), wherein said water-soluble polymer compound is
selected from the group consisting of polyvinyl pyrrolidone,
polyvinyl alcohol and carboxy methylcellulose. (7) A
surface-modifying method for a polyimide resin which comprises
[0021] a printing process wherein a predetermined pattern is
printed on the surface of a polyimide resin substrate using a
polyimide resin surface modifier containing an alkali component and
an organic solvent having hydroxy groups and a boiling point of
120.degree. C. or higher wherein the water content is 0-10% by
weight,
[0022] an organic solvent-removing process wherein an organic
solvent in the polyimide resin surface modifier pattern-printed on
the surface of said polyimide resin substrate is removed and
[0023] a water-treatment process wherein said polyimide resin
surface modifier after removing the organic solvent is brought into
contact with water.
(8) The surface-modifying method for a polyimide resin according to
(7), wherein said polyimide resin surface modifier further contains
a water-soluble polymer compound. (9) The surface-modifying method
for a polyimide resin according to (7) or (8), wherein said
printing is carried out by a screen printing method. (10) The
surface-modifying method for a polyimide resin according to (7) or
(8), wherein said printing is carried out by an inkjet printing
method.
Effect of the Invention
[0024] According to the polyimide resin surface modifier and the
surface-modifying method for a polyimide resin using the same of
the present invention, modification can be carried out in a
predetermined pattern on the polyimide resin surface without
damaging to a printing plate and/or printer by an alkaline
component in the printing process. In addition, by contacting with
water to dissociate the alkaline component in the polyimide resin
surface modifier after the printing process, alkali hydrolysis
reaction on the polyimide resin surface in a predetermined pattern
can be promoted and uniform modification of the polyimide resin
surface can be achieved sufficiently.
[0025] The metal film obtained by reducing metal ions adsorbed on
the polyimide resin surface which is surface-modified by the
surface-modifying method using the polyimide resin surface modifier
of the present invention does not have under-etch, since an etching
process is not required. In addition, since the metal film is
formed only on the predetermined pattern part, electromigration
resistance can be ensured.
BRIEF DESCRIPTION OF DRAWINGS
[0026] FIG. 1 shows an outline of one embodiment of the
surface-modifying method for a polyimide resin using the polyimide
resin surface modifier of the present invention.
EXPLANATION OF REFERENCE LETTERS
[0027] 1: Polyimide resin substrate [0028] 2: Polyimide resin
surface modifier [0029] 3: Modified part which is modified in the
form of a pattern by the polyimide resin surface modifier [0030] 4:
Water
MODES FOR CARRYING OUT THE INVENTION
1. Polyimide Resin Surface Modifier
[0031] The polyimide resin surface modifier of the present
invention contains an alkali component and an organic solvent
having hydroxy groups and a boiling point of 120.degree. C. or
higher as necessary components.
(1) Alkali Component
[0032] The alkali component used in the present invention is a
compound which shows an alkaline property by dissolving in water.
The alkali component used in the present invention can be an
organic compound or can be an inorganic compound. Preferable
examples of the inorganic alkali compounds include metal hydroxide
or nonmetal hydroxide. Preferable examples of the organic alkali
compounds include quaternary ammonium hydroxide.
[0033] Examples of quaternary ammonium hydroxide include
tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide
(TEAH), tetrapropylammonium hydroxide (TPAH) and tetrabutylammonium
hydroxide (TBAH).
[0034] Examples of metal hydroxide and nonmetal hydroxide include
alkali metal hydroxide such as sodium hydroxide and potassium
hydroxide; alkali earth metal hydroxide such as magnesium hydroxide
and calcium hydroxide; and ammonium hydroxide.
[0035] It is preferable to use an alkali component selected from
the group consisting of alkali metal hydroxide and quaternary
ammonium hydroxide.
[0036] Among them, it is most preferable to use tetramethylammonium
hydroxide (TMAH) and tetrabutylammonium hydroxide (TBAH) as the
quaternary ammonium hydroxide, and sodium hydroxide (NaOH) and
potassium hydroxide (KOH) as the alkali metal hydroxide, in terms
of solubility in a solvent.
[0037] The content of the alkali component based on the total
amount of polyimide resin surface modifier of the present invention
is preferably 0.1-10% by weight, more preferably 1-5% by weight, in
terms of converted value to KOH. By adjusting the content of the
alkali component in this range, sufficient surface modification of
the polyimide resin substrate can be achieved without damaging to a
printer.
[0038] The content of the alkali component in terms of converted
value to KOH can be determined by the following mathematical
formula:
A(KOH)=A.sub.0.times.[M(KOH)/M(A)] (Mathematical Formula)
A.sub.0: Content of the alkali component (% by weight) A(KOH):
Content of alkali component in terms of converted value to KOH (%
by weight) M(KOH): Molecular weight of KOH (=56.12) M(A): Molecular
weight of alkali component
(2) Organic Solvent
[0039] The organic solvent used in the present invention is
required to have a boiling point of 120.degree. C. or higher in
terms of handleability in the printing process. When using the
organic solvent having a boiling point less than 120.degree. C.,
the fluidity of the polyimide resin surface modifier might be
lowered in the printing process. This might cause deterioration of
printing quality and might cause difficulty in forming a precise
pattern.
[0040] Electrical polarity is required for the organic solvent so
that the alkali component can be dissolved stably, and therefore,
the presence of hydroxy groups in a molecule is required.
[0041] Furthermore, the organic solvent is required to be able to
dissolve or disperse the alkali component.
[0042] As the organic solvent having hydroxy groups and a boiling
point of 120.degree. C. or higher of the present invention, it is
preferable to use an alcoholic compound. As the alcoholic compound,
it is more preferable to use alcohols selected from the group
consisting of hydrocarbon-type alcohols, alkylene glycols and
glycol ethers.
[0043] Examples of the hydrocarbon-type alcohols include a compound
derived from acyclic saturated hydrocarbon, preferably alcohol
derived from acyclic saturated hydrocarbon having 5-10 carbon
atoms, more preferably primary alcohol having 5-9 carbon atoms.
More precisely, examples of the hydrocarbon-type alcohols include
alcohol having a boiling point of 120.degree. C. or higher among
the isomers of C5 pentanol and C6 hexanol. Preferable examples
thereof include 1-pentanol having a boiling point of 138.degree.
C., 1-hexanol having a boiling point of 158.degree. C. and
1-octanol having a boiling point of 195.degree. C.
[0044] Examples of alkylene glycols include diol-type solvents such
as ethylene glycol, diethylene glycol, triethylene glycol,
propylene glycol, dipropylene glycol and 1,3-butylene glycol.
[0045] Examples of glycol ethers include ethylene oxides such as
ethylene glycol monobutyl ether, diethylene glycol monomethyl
ether, diethylene glycol monoethyl ether and diethylene glycol
monobutyl ether; and propylene oxides such as propylene glycol
monomethyl ether, propylene glycol monobutyl ether and dipropylene
glycol monomethyl ether.
[0046] Among them, it is preferable to use a compound having a
sufficiently high boiling point in terms of printability, such as
ethylene glycol, diethylene glycol, diethylene glycol monobutyl
ether and dipropylene glycol monomethyl ether.
[0047] Two or more of these solvents can be mixed with each
other.
[0048] The content of the organic solvent having hydroxy groups and
a boiling point of 120.degree. C. or higher based on the total
amount of polyimide resin surface modifier of the present invention
is preferably 30-99.9% by weight, more preferably 50-99% by weight,
most preferably 80-99% by weight. By adjusting the content of the
organic solvent in this range, suitable printability can be given
to the polyimide resin surface modifier.
(3) Water Content
[0049] The polyimide resin surface modifier of the present
invention contains the organic solvent having hydroxy groups and a
boiling point of 120.degree. C. or higher as a main solvent, and
has the water content of 0-10% by weight, preferably 0-5% by
weight.
[0050] When the water content in the polyimide resin surface
modifier is more than 10% by weight, dissociation of the alkali
component might progress by the action of water, which might cause
enhancement of alkaline property of the polyimide resin surface
modifier to give serious damage to printers, and as a result, to
deteriorate the precision of pattern print significantly and/or to
shorten the life of printers.
[0051] According to the polyimide resin surface modifier of the
present invention, it is preferable that water is contained as few
as possible. It is most preferable that the water content is 0% by
weight. However, there are cases that the presence of water derived
from impurities contained in raw materials and/or moisture
absorption of raw materials or the modifier itself is ascertained.
Therefore, it is actually difficult to make the water content be 0%
by weight. In fact, the water content in the range of 10% by weight
or less, more preferably 5% by weight or less based on the amount
of the polyimide resin surface modifier of the present invention is
an allowable range to achieve the purpose of the present
invention.
[0052] When the water content is 10% by weight or less and the main
component is the organic solvent, since the ionization state of
water molecule in large amounts of organic solvent is different
from that in water solvent, the influence of water contained on the
activity of alkali components is thought to be small.
[0053] The purpose of the present invention is to provide a
modifier wherein the alkali component acting for modifying
polyimide is in the state not exhibiting alkali property to a
degree of damaging to a printer. One of the indicators showing the
achievement degree of the purpose is the water content in the
modifier. The modifier having the water content of 10% by weight or
less can achieve the purpose of the present invention.
(4) Water-Soluble Polymer Compound
[0054] The polyimide resin surface modifier of the present
invention can contain a water-soluble polymer compound. The
water-soluble polymer compound used in the present invention is a
compound which is soluble in the organic solvent and also in
water.
[0055] Blending a water-soluble polymer compound into the polyimide
resin surface modifier enables to control viscosity thereof
extensively. As a result, it enables to control viscosity thereof
so as to optimize for various printing processes and to prevent
missing and/or bleeding of print. Thus, printing precision can be
improved to a large extent.
[0056] In addition, by bringing the modifier into contact with
water after printing, the water-soluble polymer compound in the
polyimide resin surface modifier can take water therein to promote
dissociation of alkali component, which brings the specific
progress of modification reaction of the printed part. Furthermore,
the polyimide resin surface modifier can be removed with ease,
since the water-soluble polymer compound is soluble in water.
[0057] Preferable examples of the water-soluble polymer compounds
used in the polyimide resin surface modifier of the present
invention include a synthetic polymer compound such as polyvinyl
pyrrolidone, polyvinyl alcohol, carboxy methylcellulose, hydroxy
ethylcellulose, polyethylene oxide, sodium polyacrylate,
polyacrylamide and polyethyleneimine, and a natural polymer
compound such as cornstarch, mannan, pectin, chitosan, agar, sodium
alginate, hyaluronic acid, sericin, various gums, dextran and
gelatin.
[0058] Among them, it is preferable to use a compound selected from
the group consisting of polyvinyl pyrrolidone, polyvinyl alcohol
and carboxy methylcellulose in terms of excellent alkaline
resistance. It is particularly preferable to use polyvinyl
pyrrolidone.
[0059] In the case of using a water-soluble polymer compound, the
content thereof is preferably 0.1-60% by weight, more preferably
0.5-50% by weight, further preferably 1-10% by weight based on the
total amount of the polyimide resin surface modifier of the present
invention.
[0060] The polyimide resin surface modifier of the present
invention can be used in combination with components suitable for
the printing method employed. In the case of using the modifier for
screen printing, for example, the viscosity suitable for screen
printing can be imparted by adding additives such as pigments,
inorganic fine particles or fillers, rheology controlling agents
and dispersion stabilizers.
[0061] In the case of using the modifier for inkjet printing,
viscosity, surface tension and discharging performance can be
controlled by blending pigments, inorganic fine particles or
fillers, leveling agents, dispersion stabilizers, defoaming agents
or the like.
[0062] Known additives can be used as these components. Examples of
pigments and inorganic fine particles or fillers include talc,
bentonite, zirconium silicate, silica, nickel oxide, aluminum
oxide, barium sulfate, barium carbonate, potassium carbonate, zinc
oxide and titanium oxide.
[0063] The content of these components is not particularly limited
and can be determined appropriately in accordance with the use. The
preferable content of the components is preferably 0.5-500% by
weight, more preferably 1-300% by weight based upon the amount of
the polyimide resin surface modifier of the present invention.
2. Surface-Modifying Method for Polyimide Resin
[0064] The surface-modifying method for polyimide resin using the
polyimide resin surface modifier of the present invention, as shown
in FIG. 1 as one embodiment thereof, comprises:
[0065] a printing process wherein a predetermined pattern is
printed on the surface of a polyimide resin substrate using a
polyimide resin surface modifier of the present invention (see
Process (a) in FIG. 1)
[0066] an organic solvent-removing process wherein an organic
solvent in the polyimide resin surface modifier pattern-printed on
the surface of said polyimide resin substrate is removed (see
Process (b) in FIG. 1) and [0067] a water-treatment process wherein
said polyimide resin surface modifier after removing the organic
solvent is brought into contact with water (see Process (c) in FIG.
1).
[0068] By employing the method of printing a predetermined pattern
using the polyimide resin surface modifier containing an organic
solvent as a main solvent and then removing said organic solvent, a
predetermined pattern can be formed easily on the surface of
polyimide resin substrate by using a modifier wherein the alkali
component acting for modifying polyimide is in the state not
exhibiting alkali property to a degree of damaging to a printer.
Therefore, modification can be performed by forming a predetermined
fine pattern reliably on the surface of a polyimide resin without
damaging to a printing plate and/or printer by an alkali component
in the printing process.
[0069] The surface-modifying method for polyimide resin of the
present invention will be described below with respect to each
process.
(1) Printing Process
[0070] According to the method of the present invention, the
printing process is carried out firstly (see Process (a) in FIG.
1). According to the Process (a), the above-mentioned polyimide
resin surface modifier is used as ink, and the predetermined
pattern is printed by various printing methods on the surface of
polyimide resin substrate. Since the polyimide resin surface
modifier of the present invention has the water content of
0.about.10% by weight and its alkaline property is extremely week,
it does not exhibit alkaline property at the time of printing, and
as a result, it does not give damage to a printing plate and/or a
printer in the printing process carried out at room
temperature.
[0071] Examples of printing methods include screen printing,
gravure printing, gravure offset printing, inkjet printing and
flexographic printing. Examples of printers include various known
printers such as a screen printer, a gravure printer, a gravure
offset printer, an inkjet printer and a flexographic printer.
(2) Organic Solvent-Removing Process
[0072] According to the organic solvent-removing process, the
organic solvent having hydroxy groups and a boiling point of
120.degree. C. or higher contained in the polyimide resin surface
modifier pattern-printed on the surface of polyimide resin
substrate is removed (see Process (b) in FIG. 2).
[0073] The method for removing the organic solvent is not
particularly limited, and various methods for drying can be
employed. Examples of the methods for drying include drying under
heating, drying in a warm air flow and drying under reduced
pressure. Drying under heating is preferably employed. By removing
the organic solvent, the polyimide resin surface modifier printed
in a pattern shape loses fluidity, whereby the pattern shape to be
modified on the surface of polyimide resin substrate is determined.
When removing the organic solvent by drying under heating, heat
treatment can be carried out at preferably 40-200.degree. C., more
preferably 100-180.degree. C., for 1-120 minutes, more preferably
1-60 minutes.
[0074] According to the present invention, in the case of employing
the method of drying under heating for removing the organic
solvent, modification reaction on the surface of polyimide resin
substrate may be progressed by the alkali component contained in
the polyimide resin surface modifier.
[0075] While the precise chemical reaction mechanism may not be
clearly known, it can be presumed that said progress of
modification reaction is a result where modification by water
contained in the modifier as an impurity or by a small amount of
water absorbed in the modifier from the air after the printing
process and/or the organic solvent-removing process is promoted by
heating.
(3) Water Treatment Process
[0076] According to the method of the present invention, after the
above-mentioned organic solvent-removing process, a water treatment
process wherein the polyimide resin surface modifier after removing
the organic solvent is brought into contact with water is carried
out (see Process (c) in FIG. 1).
[0077] By bringing into contact with water, alkali component in the
polyimide resin surface modifier on the polyimide resin substrate,
wherein the main component is a remaining alkali component after
removing the organic solvent, is dissociated by water and alkali
hydrolysis reaction (modification reaction) of the polyimide resin
is progressed.
[0078] By adjusting the temperature and time of contacting with
water, the modification degree on the surface of polyimide resin
can be controlled.
[0079] In the water treatment process, the polyimide resin surface
modifier may be removed after modification of the surface of
polyimide resin substrate, and in this case, said water treatment
process can be a process doubling as a water washing process (see
Process (d) in FIG. 1) described below.
[0080] In the particular case of surface-modifying method using the
polyimide resin surface modifier containing a water-soluble polymer
compound, the water treatment process is especially important,
since the water-soluble polymer compound in the polyimide resin
surface modifier can take water therein to promote dissociation of
alkali component, and thus, surface modification reaction of the
printed part on the polyimide resin substrate can be progressed
specifically.
[0081] In addition, since the rate of alkali component is
relatively decreased by blending a water-soluble polymer compound,
contacting with water is required in order that surface
modification is performed in a more convincing way.
[0082] Since the water-soluble polymer compound is soluble in
water, the polyimide resin surface modifier can be removed easily
by water treatment. By selecting the alkali component in the
polyimide resin surface modifier appropriately, washing with water
can be doubling as the above-mentioned water treatment process.
[0083] Examples of the methods for contacting with water include a
dipping method wherein a polyimide resin substrate is dipped or
immersed in water, a spraying method wherein water is sprayed on
the surface of polyimide resin substrate by a spraying apparatus, a
water-dropping method, a water-vapor adsorbing method wherein the
polyimide resin substrate is brought into contact with water vapor
by leaving said substrate in moisture environment, a method of
contacting the surface of polyimide resin substrate with gel or a
wet cloth and an ultrasonic processing method wherein ultrasonic
wave is irradiated in water. Among them, it is preferable to employ
a water dipping method or a water-vapor adsorbing method. It is
most preferable to employ a water dipping method. Details about the
water dipping method and the water-vapor adsorbing method are
described below.
a) Water-Dipping Method
[0084] The water dipping method used in the present invention is a
method wherein a polyimide resin substrate is dipped or immersed in
water. By adjusting the temperature and/or time of dipping in
water, the degree of surface modification can be controlled. It is
preferable to dip the substrate in water at 10.degree. C. or higher
for 5 seconds or longer, more preferably to dip the substrate in
water at 20.degree. C. or higher for 90 seconds or longer, most
preferably to dip the substrate in water at 21.degree. C. for 90
seconds, whereby the surface modification reaction on the polyimide
resin substrate can be promoted sufficiently. By dipping in water,
the surface modification degree of the polyimide resin substrate
can be improved dramatically to the degree of 3 times or more
compared with that in the case of not dipping in water.
[0085] In addition, it is possible to use another dipping method of
dipping in an arbitrary aqueous solution, since a similar effect
can also be obtained by using an aqueous solution wherein some sort
of solute is dissolved. In order to prevent undesirable chemical
changes on the surface of polyimide resin, it is preferable to use
a solution with pH of 9 or lower, preferably neutral pH or lower.
It is most preferable to use pure water which is not affected by
ions.
[0086] Examples of arbitrary aqueous solutions include various
buffer solutions. In the case of modifying a polyimide resin
elongated film continuously, for example, there is a benefit of
using a buffer solution. That is, when a water treatment process is
carried out by passing the polyimide resin elongated film through a
tank storing water, apart of the surface of film that should not be
modified originally might be modified by the increase in pH of the
water stored in tank caused by dropping out of apart of the alkali
component in the modifier to the water stored in tank during the
water treatment.
[0087] Examples of the buffer solutions include a phosphate buffer
solution, a citrate buffer solution, a borate buffer solution and
Tris buffer.
b) Water-Vapor Adsorbing Method
[0088] According to the water-vapor adsorbing method, after
printing the polyimide resin surface modifier on the polyimide
resin substrate and removing the organic solvent in the modifier by
volatilizing, the polyimide resin substrate is brought into contact
with water vapor by leaving said substrate in moist air so that
water vapor is adsorbed in the modifier thereon. Subsequently,
modification is progressed by heating the substrate. This method is
characterized in that the substrate does not contact with liquid
water directly. The modification degree on the polyimide resin can
be controlled by adjusting the temperature and humidity of moist
air, the time of leaving and the temperature and time of
heating.
[0089] For example, water-vapor adsorption can be carried out at
room temperature and normal humidity, preferably at a temperature
of 10-40.degree. C. and humidity of 30-90%. The time of leaving is
preferably in the range from 1 minute to 24 hours depending on the
condition of air.
[0090] The heat treatment can be carried out at preferably
40-200.degree. C., more preferably 100-180.degree. C., for 1-120
minutes, more preferably 1-60 minutes.
[0091] In addition, the modification degree on the polyimide resin
can be controlled by repeating the cycle of a combination process
of water-vapor adsorption in air and heat treatment more than once.
In this case, it is preferable to repeat the above cycle of
combination process 2-10 times.
[0092] In the case of employing the water-vapor adsorbing method
for the water treatment process in the present invention, since the
modifier is not removed at the time of water treatment, the
modifier is removed at the time of water washing process.
(4) Washing Process
[0093] After finishing necessary modification in the water
treatment process of the present invention, it is possible to wash
the surface of polyimide resin substrate by an adequate solvent so
that the polyimide resin surface modifier is not remained on the
modified part of the surface of polyimide resin substrate after
modification (washing process (d) in FIG. 1).
[0094] In terms of plate adhesiveness and/or uniform deposition
selectivity, it is desirable that components of polyimide resin
surface modifier are not remained at the time of applying catalysts
and depositing to the modified part of the polyimide resin
substrate.
[0095] Examples of preferable solvents for washing include water.
As a water-washing method, known washing methods can be employed.
Examples of known washing methods include ultrasonic washing, spray
and/or shower washing, brush washing, dip washing and two-fluid
washing. These washing methods can be selected appropriately and
are not particularly limited.
[0096] The washing process by water can be doubling as the
above-mentioned water treatment process, especially the water
treatment process by a water dipping method. Or, the washing
process can be carried out in addition to the above-mentioned water
treatment process subsequently, if necessary.
[0097] In the case of using a polyimide resin surface modifier
containing a water-soluble polymer compound, it is possible to
remove the polyimide resin surface modifier easily by washing with
water, since the water-soluble polymer compound is soluble in
water.
[0098] By selecting the alkali component in the polyimide resin
surface modifier appropriately, the water washing process can be
doubling as the above-mentioned water treatment process.
[0099] On the surface of the polyimide resin modified by the
surface modifying method of the present invention, carboxy groups
which are capable of adsorbing metal ions are generated. Metal
salts can be formed by bringing a solution containing metal ions
into contact with the carboxy groups on said surface. Subsequently,
a metal film can be formed by reducing the metal salts and plating.
As a result, a conductive pattern can be formed on the polyimide
resin.
[0100] Examples of the metal ions include a palladium ion. Examples
of the metal films include a nickel film and a copper film.
[0101] As a polyimide resin applicable in the present invention, it
is preferable to use a polymer having heat resistance and chemical
resistance in light of intended use as electronic materials, and
having an imide ring skeleton such as polyimide and polyetherimide,
wherein carboxy groups can be generated accompanied with
ring-opening reaction of an imide ring in the main chain by alkali
hydrolysis reaction.
[0102] Examples of polyimide resin substrates used in the present
invention include a flexible printed-wiring board, a flexible sheet
heater, a configurational wiring substrate, electromagnetic
shielding materials, electrodes for solar cells, an antenna for IC
tags, a flexible antenna and electrodes for lighting, which are
formed of the above-mentioned polyimide resins.
EXAMPLES
[0103] The present invention will be described in more detail below
referring to Examples and Comparative Examples, which are not
intended to limit the scope of the present invention.
Examples 1-2, Comparative Examples 1-3
[0104] Effects of surface modification of polyimide resins printed
by screen printing using polyimide resin surface modifiers of
Examples 1-2 and Comparative Examples 1-3 shown in Table 1 were
evaluated.
[0105] Evaluations were performed on modification property of
polyimide resins, damages to a screen printer and a pattern
printing property of screen printing.
[0106] The surface modifiers used here had been proved to show
alkalinity of pH 10 or higher when measured after being diluted 100
times with water. It means that each of the surface modifiers
themselves has a sufficient ability to modify a polyimide resin
under the presence of a sufficient quantity of water to dissociate
an alkali component to show an alkaline property.
[0107] In the case of Examples and Comparative Examples wherein
water was not added intentionally, the content of water in each
polyimide resin surface modifier shown in Table 1 means the content
of water derived from raw materials or incorporated by moisture
adsorption from the air unintentionally.
[0108] The content of water incorporated by moisture adsorption
from the air was calculated by the rate of increase in weight when
2 ml of the polyimide resin surface modifier was left in the open
air at room temperature for 4 hours.
[0109] The content of water derived from raw materials was
determined with reference to the literatures concerned or the
like.
[0110] In the case of Examples and Comparative Examples wherein
water was added intentionally, the content of water shown in Table
1 does not comprise water derived from raw materials or
incorporated by moisture adsorption from the air
unintentionally.
(Evaluation of Modification Property of Polyimide Resin)
[0111] 2 .mu.L of polyimide resin surface modifier was dropped onto
a polyimide film, brand name "Kapton 100H" manufactured by DU
PONT-TORAY CO., LTD., and heat treatment was carried out at
150.degree. C. for 20 minutes to remove the organic solvent in the
polyimide resin surface modifier.
[0112] After heat treatment, the polyimide resin surface modifier
remained on the film was removed by washing by means of shower
washing using water.
[0113] Subsequently, modifying property on the part of being heat
treated was evaluated by a Fourier transform infrared
spectrophotometer (FT-IR). The measurement by FT-IR was carried out
by an ATR method and a ratio of the adsorption strength at 1718.3
cm.sup.-1 derived from an imide ring to the adsorption strength at
1502.3 cm.sup.-1 derived from a benzene ring on the part of being
modified was calculated, which was taken as an imide ring-residual
degree. Based on said imide ring-residual degree, the ratio of the
imide ring-residual degree for heat-treated polyimide to the imide
ring-residual degree of untreated polyimide which was denoted as
100% was calculated and the result was taken as an imide
ring-residual ratio. The imide ring-residual ratio was taken as an
index of modification property, and modification property of a
polyimide resin was evaluated based on the following standard:
.largecircle.: the imide ring-residual ratio after heating was less
than 50%. .DELTA.: the imide ring-residual ratio after heating was
in the range between 50% or more and less than 75%. X: the imide
ring-residual ratio after heating was 75% or more.
(Evaluation of Damage to Screen Printer)
[0114] A photosensitive emulsion was applied on a stainless mesh so
as to form lines having a width of 540 .mu.m and a space of 200
.mu.m, and thereby, a screen mask in the form of strip having the
line width of 200 .mu.m was formed.
[0115] A segment of the screen mask was immersed into a polyimide
resin surface modifier for 3 hours. Immediately after immersion,
the screen mask segment was watched by a microscope to observe
appearance changes of the photosensitive emulsion between before
and after the immersion. At the same time, a swelling amount was
measured by the change of space widths among the emulsion lines as
follows.
(Measurement of Swelling Amount)
[0116] Photosensitive emulsion applied so as to form a line having
a space width of 200 .mu.m was immersed into a modifier, and then,
the space width was measured again. The swelling amount was
determined by calculating the difference between the space before
immersing (=200 .mu.m) and the space, after immersing which was
usually narrowed by swelling of the emulsion.
[Swelling Amount (.mu.m)]=[S1 (=200 .mu.m)]-[S2 (.mu.m)]
S1: Space before immersing S2: Space after immersing
[0117] Based on these results, damages by the polyimide resin
surface modifier to the screen mask were evaluated as follows:
Appearance Change of Photosensitive Emulsion;
[0118] .largecircle.: No change in appearance was observed after
immersion. X: Changes such as change in color were observed after
immersion.
Swelling Amount of Photosensitive Emulsion;
[0119] .largecircle.: The swelling amount was less than 4 .mu.m.
.DELTA.: The swelling amount was in the range between 4 .mu.m or
more and less than 8 .mu.m. X: The swelling amount was 8 .mu.m or
more.
(Evaluation of Pattern Printing Property by Screen Printing)
[0120] Only in the case of evaluation of pattern printing property
by screen printing, a polyimide resin surface modifier wherein a
thickening component was added to impart adequate viscosity was
used. That is, a thickening component prepared by blending
polyvinyl pyrrolidone, brand name "K-30", manufactured by NIPPON
SHOKUBAI CO., LTD., which has thickening abilities for the organic
solvent in said modifier and zirconium silicate which can be
dispersed in the organic solvent by the ratio of [polyvinyl
pyrrolidone]:[zirconium silicate]=35:65 (weight ratio) was added to
the modifier by the ratio of 1 based on 1 of the modifier (weight
ratio), so as to have viscosity of 20-150 Pas under the shear rate
of 10 s.sup.-1 at 25.degree. C.
[0121] By using the polyimide resin surface modifier thus thickened
and by using a screen mask formed into an arbitrary pattern having
a pattern size of 150 mm.times.150 mm, screen printing on the
polyimide resin film was carried out 20 times continuously.
[0122] After printing, printing blurring on a part of being
patterned and bleeding of solvent under the screen mask were
observed. Pattern printing property of the modifier was evaluated
as follows:
.largecircle.: No blurring or bleeding was observed after
continuous printing of 20 times. X: Blurring and/or bleeding were
observed after continuous printing of 20 times.
TABLE-US-00001 TABLE 1 Content of Component(*1) Damage to Printer
Pattern (% by weight) Water Content Modification Change in Swelling
Printing Component (converted value to KOH) (% by weight) Property
Appearance Amount Property Example 1 DEGMBE 92 0.6 .largecircle.
.largecircle. .largecircle. .largecircle. TBAH 8(1.7) Example 2 DEG
98 9.7 .largecircle. .largecircle. .largecircle. .largecircle. KOH
2 Comp. Ex. 1 Water 98 98 .largecircle. X X X KOH 2 Comp. Ex. 2
MeOH 92 No Data .largecircle. X .DELTA. X TBAH 8(1.7) (*2) Comp.
Ex. 3 DEG 68 30 .largecircle. X X X Water 30 KOH 2 The
abbreviations in the above Table 1 mean as follows: DEGMBE:
Diethylene glycol monobutyl ether (boiling point: 188.3.degree. C.)
DEG: Diethylene glycol (boiling point: 244.3.degree. C.) MeOH:
Methanol which is a special grade reagent manufactured by NACALAI
TESQUE, INC. (boiling point: 64.7.degree. C.) Water: (boiling
point: 100.degree. C.) KOH: Potassium Hydroxide TBAH:
Tetrabutylammonium hydroxide (*1)The value provided in parenthesis
for the content of TBAH is a content of TBAH in terms of a
converted value to KOH (% by weight). (*2) "No Data" means that the
water content was not determined since the water content of
methanol used was not clear.
[0123] According to the results of the above Examples 1 and 2, each
of the polyimide resin surface modifiers used in these examples had
modification property of polyimide resin and was excellent in
screen printing property, whereas no damage to a printer was
observed.
[0124] On the other hand, in the case of using the polyimide resin
surface modifiers used in Comparative Examples 1-3, damages to the
screen printer such as color change and/or swelling in the emulsion
of screen mask were observed. For pattern printing property of ink,
in addition, blurring and/or bleeding were also observed.
Examples 3-7, Comparative Examples 4-5
[0125] Using the polyimide resin surface modifiers having the
compositions shown in Table 2, effects of surface modification of
polyimide resin by inkjet printing were evaluated.
[0126] Modification property of polyimide resin was evaluated in
the same manner as in Examples 1-2.
[0127] In addition to the modification property, damages to an
inkjet printer and ink discharging stability in an inkjet head were
evaluated as an evaluation of inkjet printing property as described
below. The surface modifiers used here had been proved to show
alkalinity of pH 10 or higher when measured after being diluted 100
times with water.
(Evaluation of Damage to Inkjet Printer)
[0128] Change in liquid repellency of an orifice plate surface
resin by contacting with the polyimide resin surface modifiers was
checked. Firstly, the water contact angle on the orifice plate
surface resin was measured and subsequently the orifice plate
surface resin was brought into contact with a polyimide resin
surface modifier at room temperature for 24 hours. Then, the water
contact angle on the orifice plate surface resin was measured
again. In accordance with the decreasing rate of water contact
angle on the orifice plate surface resin, damage to an inkjet head
was evaluated as follows:
.largecircle.: The decreasing rate of water contact angle was less
than 5%. .DELTA.: The decreasing rate of water contact angle was in
the range between 5% or more and less than 20%. X: The decreasing
rate of water contact angle was 20% or more.
(Evaluation of Ink Discharging Stability)
[0129] By using a polyimide resin surface modifier as an ink, a 20
mm long line was printed by discharging said ink from an inkjet
head. Then, the number of breaking places in the printed line was
counted and ink discharging stability was evaluated based on the
number of breaking places.
[0130] Only in the case of evaluation of ink discharging stability,
a polyimide resin surface modifier wherein a thickening component
was added to impart adequate viscosity was used in Example 3,
Example 4, Comparative Example 4, and Comparative Example 5. That
is, polyvinyl pyrrolidone, brand name "K-30", manufactured by
NIPPON SHOKUBAI CO., LTD., which has thickening abilities for the
organic solvent in said modifier was added to the modifier by the
ratio of 1 based on 100 of the modifier (weight ratio,
approximately 1% by weight), so as to have viscosity of 5-12 mPas
at 30.degree. C.
[0131] With regard to Examples 5, 6 and 7, polyvinyl pyrrolidone
was not added to the modifiers since each of the modifiers used
already had viscosity of 5-12 mPas without adding polyvinyl
pyrrolidone.
[0132] Evaluation of ink discharging stability was performed by the
following standard:
.largecircle.: The number of breaking places was less than 0.05/mm.
.DELTA.: The number of breaking places was in the range between
0.05/mm or more and less than 0.5/mm. X: The number of breaking
places was 0.5/mm or more.
TABLE-US-00002 TABLE 2 Content of Component(*1) ink (% by weight)
Water Content Modification Damage to discharging Component
(converted value to KOH) (% by weight) Property Printer Stability
Example 3 DPGMME 92 0.6 .largecircle. .largecircle. .largecircle.
TBAH 8(1.7) Example 4 DEGMBE 98 7.2 .largecircle. .largecircle.
.largecircle. KOH 2 Example 5 DPGMME 67.5 7.3 .largecircle.
.largecircle. .largecircle. EG 30 KOH 2.5 Example 6 EGMBE 72 4.2
.largecircle. .largecircle. .largecircle. EG 25 KOH 3 Example 7
EGMME 72 0.5 .largecircle. .largecircle. .largecircle. EG 25 KOH 3
Comp. Ex. 4 Water 98 98 .largecircle. X X KOH 2 Comp. Ex. 5 i-PrOH
92 No Data .DELTA. .DELTA. X TBAH 8(1.7) (*2) The abbreviations in
the above Table 2 mean as follows: DPGMME: Dipropylene glycol
monomethyl ether (boiling point: 230.4.degree. C.) DEGMBE:
Diethylene glycol monobutyl ether (boiling point: 188.3.degree. C.)
DEG: Diethylene glycol (boiling point: 244.3.degree. C.) EGMBE:
Ethylene glycol monobutyl ether (boiling point: 171.degree. C.)
EGMME: Ethylene glycol monomethyl ether (boiling point: 124.degree.
C.) EG: Ethylene glycol (boiling point: 197.3.degree. C.) MeOH:
Methanol which is a special grade reagent manufactured by NACALAI
TESQUE, INC. (boiling point: 64.7.degree. C.) i-PrOH: Isopropanol
(boiling point: 82.4.degree. C.) Water: (boiling point: 100.degree.
C.) KOH: Potassium Hydroxide TBAH: Tetrabutylammonium hydroxide
(*1)The value provided in parenthesis for the content of TBAH is a
content of TBAH in terms of a converted value to KOH (% by weight).
(*2) "No Data" means that the water content was not determined
since the water content of methanol used was not clear.
[0133] In Examples 3-7, the polyimide resin surface modifiers
exhibited excellent ink discharging stability and modification
property of polyimide resin without damaging to a printer.
[0134] In Comparative Examples 4-5, on the other hand, the
polyimide resin surface modifiers damaged to a printer and
exhibited inferior ink discharging stability.
Preparation Examples 1-5
[0135] Polyimide resin surface modifier compositions containing
water-soluble polymer compounds each having a composition ratio
shown in the following Table 3 were prepared (hereinafter,
Compositions 1-5). Polyvinyl pyrrolidone, brand name "PVP K-90",
manufactured by NIPPON SHOKUBAI CO., LTD., was used for a
water-soluble polymer compound.
[0136] Tetrabutylammonium hydroxide (TBAH), which was a TBAH-37%
methanol solution manufactured by Tokyo Chemical Industry Co.,
Ltd., and potassium hydroxide manufactured by NACALAI TESQUE, INC.
were used for an alkali component.
[0137] Diethylene glycol, manufactured by NACALAI TESQUE, INC., and
dipropylene glycol monomethyl ether, manufactured by NACALAI
TESQUE, INC., were used for an organic solvent.
[0138] Talc, brand name of "FG-15", manufactured by Nippon Talc
Co., Ltd.; bentonite, brand name of "SD-2", manufactured by Toshin
Chemicals Co., Ltd.; zirconium silicate, brand name of "Micropax
SPZ", manufactured by HakusuiTech Co., Ltd.; and nickel oxide,
manufactured by Tanaka Chemical Corporation; were used for a filler
component.
[0139] In the case of a composition wherein water was not added
intentionally, the water content of each polyimide resin surface
modifier composition shown in Table 3 was calculated based on the
water content derived from raw materials or incorporated by
moisture adsorption from the air unintentionally.
[0140] The content of water incorporated by moisture adsorption
from the air was calculated by the rate of increase in weight when
the polyimide resin surface modifier composition was left in the
open air at room temperature (21.degree. C.) for 2 hours.
[0141] The content of water derived from raw materials was
determined with reference to the literatures concerned or the
like.
[0142] In the case of a composition wherein water was added
intentionally, the water content shown in Table 3 comprise not only
the amount of water added intentionally, but also the amount of
water derived from raw materials or incorporated by moisture
adsorption from the air unintentionally.
TABLE-US-00003 TABLE 3 unit: % by weight Composition Composition
Composition Composition Composition 1 2 3 4 5 Polyimide Resin
Polymer Compound PVP 2.8 8.6 5.7 9.1 6.5 Surface Modifier Alkali
TBAH 3.4 -- -- -- -- Component (converted (0.73) value to KOH) KOH
-- 1.3 1.6 1.5 1.0 Organic DEG 16.9 90.0 92.7 89.3 17.5 Solvent
DPGMME 76.9 -- -- -- -- Water -- -- -- -- 75.0 Total 100 100 100
100 100 Water Content 4.2 2.6 2.9 4.6 75.5 Filler Talc 11.2 -- 78.6
-- -- Bentonite 1.2 -- -- -- -- Zirconium Silicate -- 231.1 -- --
150.0 Nickel Oxide -- -- -- 407.1 -- The abbreviations in the above
Table 3 mean as follows: PVP: Polyvinyl pyrrolidone DPGMME:
Dipropylene glycol monomethyl ether (boiling point: 230.4.degree.
C.) DEG: Diethylene glycol (boiling point: 244.3.degree. C.) KOH:
Potassium Hydroxide TBAH: Tetrabutylammonium hydroxide
Examples 8-9, Comparative Example 6
[0143] The Compositions 1, 2 and 5 shown in the above Table 3 were
subjected to evaluation of damage to a screen printer by means of
the following method:
(Evaluation of Damage to Screen Printer)
[0144] A photosensitive emulsion was applied on a stainless mesh to
form a screen mask in the form of a strip line having the line
width of 200 .mu.m.
[0145] A segment of the screen mask was brought into contact with
each of the Compositions 1, 2 and 5 for 3 hours. The screen mask
segment was watched by a microscope to observe appearance changes
of the photosensitive emulsion between before and after the
contact. At the same time, a swelling amount was measured by the
change of space widths among the emulsion lines in the same manner
as in Examples 1-2.
[0146] Based on these results, damage by the compositions to the
screen mask was evaluated as follows:
.largecircle.: No change in appearance was observed after contact.
X: Changes such as change in color were observed after contact.
TABLE-US-00004 TABLE 4 Ex. 8 Ex. 9 Comp. Ex. 6 Composition
Composition 1 Composition 2 Composition 5 Water Content 4.2 2.6
75.5 (% by weight) Damage to Screen .largecircle. .largecircle. X
Mask
[0147] As shown in the above results, it was clear that the
compositions having the water content of 10% by weight or less did
not give damage to the screen mask. In the case of using a
composition having the water content of more than 10% by weight, on
the other hand, damage to the screen mask accompanied by change in
appearance of a photosensitive emulsion might occur.
Examples 10-13
[0148] Using Compositions 1-4 shown in the above Table 3,
modification treatment on a polyimide resin substrate was carried
out and evaluation was performed.
[0149] Each of Compositions 1-4 was printed by screen printing on a
polyimide resin film substrate having a film thickness of 25 .mu.m,
brand name "Kapton 100H" manufactured by DU PONT-TORAY CO., LTD.,
to form a linear pattern (Printing Process). Subsequently, the
polyimide resin substrate was subjected to a drying process in a
150.degree. C. oven for 30 minutes (Organic Solvent Removing
Process).
[0150] After the drying process, the polyimide resin substrate was
immersed into water at 21.degree. C. for 90 seconds to be brought
into contact with water to be modified (Water Treatment Process).
Then, the composition was removed by ultrasonic cleaning in pure
water for 3 minutes (Washing Process). In this manner, the surface
modification of the polyimide resin substrate was carried out by
the organic solvent removing process, the water treatment process
and the washing process.
[0151] Chemical changes on the surface of the polyimide resin
substrate before and after the modification by the above-mentioned
processes was measured by a Fourier transform infrared
spectrophotometer (FT-IR) and the rate of modification on the
surface of polyimide resin was made to be numerical values. Plating
deposition ability was evaluated by observing the appearance after
electroless nickel plating. Durability of printed materials on the
polyimide resin and removal performance were also evaluated by
observation. The results were shown in Table 5.
(Numerical Values of Rate of Modification)
[0152] After the compositions were printed and modification
treatment was carried out on the surface of polyimide resin, the
surface was subjected to measurement by a Fourier transform
infrared spectrophotometer (FT-IR) to obtain an absorption
spectrum. The absorption peak strength at 1718.3 cm.sup.-1 derived
from an imide ring (hereinafter, "Abs-imide ring") and the
absorption peak strength at 1502.3 cm.sup.-1 derived from a benzene
ring (hereinafter, "Abs-benzene ring") were used to calculate an
absorption peak strength rate of imide ring to benzene ring
([Abs-imide ring]/[Abs-benzene ring]). The value of the absorption
peak strength rate thus obtained was represented by "[Abs*]".
[0153] The absorption peak strength rate of the polyimide resin
before modification treatment which was represented by
"[Abs*].sub.0" was used as a standard to calculate a rate of change
to the absorption peak strength rate of the polyimide resin after
modification treatment in each Examples and Comparative Examples
which was represented by "[Abs*]". Thereby, the rate of imide rings
opened by alkali hydrolysis or the degree of progress of
modification reaction was made to be numerical value, which was
represented as a rate of modification (%).
(Evaluation of Plating Deposition)
[0154] After the compositions were printed and modification
treatment was carried out on the surface of polyimide resin
substrate, the substrate was subjected to catalyst application,
reduction, electroless nickel plating and a pattern plate was
deposited on the surface of polyimide resin. In the
catalyst-application process, the substrate was immersed into a
0.15 g/L palladium chloride solution at 40.degree. C. for 3
minutes. In the reducing process, the substrate was immersed into a
0.02M dimethylamine borane solution with a pH5.8 citrate buffer at
40.degree. C. for 3 minutes. In the plating process, the substrate
was immersed into an electroless nickel plating bath, brand name
"ES-500", manufactured by JCU CORPORATION, at 40.degree. C. for 1
minute.
[0155] Plating deposition on the surface of the polyimide resin
after modification was evaluated as follows:
.largecircle.: Excellent in deposition .DELTA.: Deposited with
lacking in uniformity X: Defect in deposition
(Evaluation of Durability in Printed Material)
[0156] The compositions were printed on a polyimide resin substrate
and were subjected to a drying process (Printing Process and
Organic Solvent Removing Process) to form a linear pattern printed
material. The polyimide resin substrate having the linear pattern
printed material thereon was bended 5 times in a direction vertical
to the linear pattern, and then, form change of the printed
material was observed to evaluate.
.largecircle.: No change in the form of printed material by bending
the substrate was observed. .DELTA.: Cracking or falling off of the
printed material by bending the substrate was observed. X: Cracking
or falling off of the printed material on the polyimide resin
substrate was observed at the time of drying.
(Removal Performance)
[0157] Each of the compositions was printed on a polyimide resin
substrate "Kapton 100H" by using a screen printing plate of a
stripe pattern. Subsequently, the substrate was subjected to a
drying process in an oven at 120.degree. C. for 30 minutes (Organic
Solvent Removing Process), and was immersed into pure water at
21.degree. C. for 90 seconds (water treatment process or
modification by contacting with water). Then, the substrate was
subjected to ultrasonic cleaning in pure water at a frequency of 40
kHz for 10 minutes.
[0158] The surface of the polyimide resin substrate was observed by
a microscope of 100 magnifications and the presence or absence of
residues was evaluated.
.largecircle.: No residues was observed. X: Presence of residues
was observed.
TABLE-US-00005 TABLE 5 Example 10 Example 11 Example 12 Example 13
Compound Compound 1 Compound 2 Compound 3 Compound 4 Alkali
Component TBAH KOH KOH KOH Polymer Compound Water Soluble Water
Soluble Water Soluble Water Soluble Immerse to Pure Water
21.degree. C. 21.degree. C. 21.degree. C. 21.degree. C. 90 sec 90
sec 90 sec 90 sec Rate of Modification (%) 31 72 60 59 Removal
Performance .largecircle. .largecircle. .largecircle. .largecircle.
Plate Deposition .largecircle. .largecircle. .largecircle.
.largecircle. Durability of Printed Material .largecircle.
.largecircle. .largecircle. .largecircle. Water Content (%) 4.2 2.6
2.9 4.6
[0159] In light of the above results, it was clear that the
modification degree on the polyimide resin was improved and uniform
plate deposition was ensured by using a polyimide resin surface
modifier composition containing a water-soluble polymer compound of
the present invention. In addition, sufficient durability of
printed materials was also ensured by using said polyimide resin
surface modifier composition containing a water-soluble polymer
compound. Furthermore, the polyimide resin surface modifier
composition containing a water-soluble polymer compound was
entirely removed from the surface of polyimide resin substrate by a
removing process using water.
Examples 14-22
[0160] Composition 1 or 2 was used to print on a polyimide resin
substrate "Kapton 100H" by screen printing, and the substrate was
subjected to a drying process in an oven at 150.degree. C. for 30
minutes. Subsequently, the substrate was subjected to a water
treatment process using various water-contacting methods such as a
dipping method, a spray method, a wet cloth-contacting method, a
dropping method, a gel-contacting method and an ultrasonic
processing as described below, and then, modification promoting
effect was evaluated.
[0161] After modification, plating was carried out in the same
manner as in Example 10 and various evaluations were performed in
the same manner as described above. The results were shown in Table
6.
TABLE-US-00006 TABLE 6 Ex. 14 Ex. 15 Ex. 16 Ex. 17 Ex. 18 Ex. 19
Ex. 20 Ex. 21 Ex. 22 Compound 2 1 1 1 2 2 2 2 2 Water Contacting
Method Dip Dip Dip Dip Spray Wet Drop Gel Ultrasonic 21.degree. C.
21.degree. C. 21.degree. C. 40.degree. C. Cloth Time of Contact 90
sec 60 sec 180 sec 90 sec 90 sec 90 sec 90 sec 90 sec 0 sec Rate of
Modification (%) 72 16 30 33 52 24 54 81 22 Plate Deposition
.largecircle. .DELTA. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. Removal
Performance .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. The abbreviations in the above Table 6 mean as
follows: *Dip (a dipping method): The printed material was immersed
into pure water at 21.degree. C. or 40.degree. C., and after the
lapse of prescribed time, ultrasonic cleaning was carried out in
pure water. *Spray (a spray method): Pure water was sprayed onto
the surface of printed material, and after the lapse of prescribed
time, ultrasonic cleaning was carried out in pure water. *Wet cloth
(a wet cloth-contacting method): A sheet of cloth, brand name
"HydroCloth", was soaked in water. The surface of printed material
was brought into contact with said cloth, and after the lapse of
prescribed time, ultrasonic cleaning was carried out in pure water.
*Drop (a dropping method): 500 .mu.L of pure water was dropped onto
the printed material, and after the lapse of prescribed time,
ultrasonic cleaning was carried out in pure water. *Gel (a
gel-contacting method): Gel of 8% carboxy methylcellulose, brand
name "Cellogen HE-600F", manufactured by Dai-Ichi Kogyo Seiyaku Co.
Ltd., was prepared by using water. The surface of printed material
was brought into contact with said gel, and after the lapse of
prescribed time, ultrasonic cleaning was carried out in pure water.
*Ultrasonic (an ultrasonic processing): Ultrasonic irradiation at a
frequency of 40 kHz was carried out for 5 minutes while the printed
material was immersed in pure water at 25.degree. C.
[0162] Ultrasonic cleaning performed after contacting with water in
each method was carried out by irradiating ultrasonic wave at a
frequency of 40 kHz for 5 minutes while the printed material was
immersed in pure water at 25.degree. C.
[0163] Seeing the above results, in each case when various
water-contacting methods were performed by using the polyimide
resin surface modifier compositions containing water-soluble
polymer compounds, sufficiently high rate of modification on the
polyimide resin substrate was achieved and a uniform and even
plating film was formed thereon.
INDUSTRIAL APPLICABILITY
[0164] According to the present invention, by using the
above-mentioned polyimide resin surface modifier and the surface
modifying method of polyimide resin using the same, damages to
printing plates and/or printers can be suppressed, and opening of
imide rings on the surface of polyimide resin substrate can be
caused evenly and sufficiently. By adsorbing metal ions on the
polyimide resin thus surface modified and by reducing the metal
ions to form a metal film, a metal film pattern excellent in
electromigration resistance can be obtained without under etching.
Thus, the method of the present invention can be widely utilized
for manufacturing circuit boards such as a flexible printed-wiring
board.
* * * * *