| JSR TECHNICAL REVIEW No.104 (March, 1997) |
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| Toughening of Epoxy Resins by Modification with Crosslinked Rubber |
 Epoxy
resins have superior physical properties and are widely
used as adhesives, matrix resins for FRP and electrical
insulations. However, they also have some defects like,
for instance, poor resistance against crack propagation
due to their brittleness. In order to toughen epoxy resins,
liquid rubbers such as carboxyl-terminated butadiene-acrylonitrile
rubber (CTBN) are incorporated into the resins matrix.
But, at the same time, the introduction of CTBN tends
to cause serious drawbacks such as lowing Tg and poor
reproducibility of improving performance. We have done
an intensive work on synthesis of crosslinked rubber and
evaluation of its performance, which finally substantiated
that the crosslinked rubber was much more effective in
toughening epoxy resins without lowering Tg compared to
CTBN. We concluded that the most suitable candidate was
carboxylated NBR, typical analytical value of which were
20% of bound AN and 10mgKOH/gr. of acid value (XER-91).
We also examined the improvement mechanism of crosslinked
rubber. |
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| A Study on Blistering Resistance of Coated Paper with a New Air Permeability Tester |
| We
have developed a new air permeability tester with which
we can measure the acceleration of the air permeability
of coated paper under high temperature (~300ºC) and pressure
(~4.00kgf/cm2) during a short time. These conditions are
close to the real world in the drying process of web-offset
printing press. The acceleration of the air permeability
is thought to be an ability in the coating layer to respond
to rising water vapor pressure in a short time during
the drying process of web-offset printing press. With
the new air permeability tester, the correlation between
the acceleration of the air permeability and the blistering
resistance of various coated papers was investigated.
These coated papers were prepared with different binders,
amount of binders, pigment formulations and binder contents
in each coating layer. We found that the acceleration
of the air permeability was more strongly related to the
blistering tendency of coated papers, than conventional
air permeability testers. So, the result indicates that
the new air permeability testers is very useful in predicting
the blistering tendency of coated paper. |
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| PED Stabilized Chemically Amplified Photoresist |
| The
influence of the baking condition on PED stability and
the resist profile of a chemically amplified (CA) photoresist
was investigated One of the most serious problems for
the use of CA photoresists is the -topformation. A
high temperature softbake has been suggested to prevent
this problem. Standing wave, however, was observed with
high temperature softbake. The role and the effect of
the banking temperature for softbake and PEB were discussed.
Our investigation suggests that; 1) Low temperature softbake
reduces standing wave. 2) High temperature PEB prevents
T-top. Another problem, pattern deformation, came out
with the combination of low temperature softbake and high
temperature PEB. Stepwise PEB is effective to prevent
both T-top and pattern deformation. The first low temperature
PEB decomposes the protecting groups in the body of the
resist film without pattern deformation and the subsequent
high temperature PEB eliminates T-top. We also investigated
the role of PEB temperature on prevention of T-top. Photoacid
recovers the activity to decompose the protecting group
even though the acid is coupled with ammonia, a basic
contaminant from the environment. The activity of the
ammonium salt of the photoacid and the activation energy
of the protection group are thought to be the key factor
on environmental stability. |
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| Color Resists for Color Filters |
| Among
the color filter manufacturing methods, pigment-dispersed
method is regarded as the most suitable for large, fine-resolution
CFs at present. In this paper, the compositions and reaction
mechanism of representative types of pigment-dispersed
color resists (PDCRs) are described. Binder polymer is
a key component for the radical polymerization type PDCRs,
and an example of the binder polymer design to obtain
residue free PDCRs is shown. The properties of the residue
free PDCR are reported. |
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