U.S. patent application number 13/138807 was filed with the patent office on 2012-04-19 for binder composition for non-aqueous secondary battery electrode.
This patent application is currently assigned to TOYOCHEM CO., LTD.. Invention is credited to Shingo Ikeda, Sachiko Kinoshita, Takaaki Koike, Koichiro Miyajima, Yasuyuki Moroishi, Hiromi Yokoyama.
Application Number | 20120095131 13/138807 |
Document ID | / |
Family ID | 42828403 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120095131 |
Kind Code |
A1 |
Kinoshita; Sachiko ; et
al. |
April 19, 2012 |
BINDER COMPOSITION FOR NON-AQUEOUS SECONDARY BATTERY ELECTRODE
Abstract
Disclosed is a binder composition for a non-aqueous secondary
battery electrode, which enables the production of a non-aqueous
secondary battery that has excellent adhesion to a current
collector or an electrode and can retain a high electric discharge
capacity even when charge and discharge are repeated or under a
high-temperature environment produced as a result of the generation
of heat. Specifically disclosed is a binder composition for a
non-aqueous secondary battery electrode, which comprises functional
group-containing crosslinked resin microparticles produced by
polymerizing the following components (A) to (C): (A) at least one
monomer selected from the group consisting of (a) a monomer having
one ethylenically unsaturated group per molecule and also having a
monofunctional or polyfunctional epoxy group, (b) a monomer having
one ethylenically unsaturated group per molecule and also having a
monofunctional or polyfunctional amide group, and (c) a monomer
having one ethylenically unsaturated group per molecule and also
having a monofunctional or polyfunctional hydroxy group; (B) at
least one monomer selected from the group consisting of (d) a
monomer having one ethylenically unsaturated group per molecule and
also having an alkoxysilyl group and (e) a monomer having at least
two ethylenically unsaturated groups per molecule; and (C) (k) a
monomer which has an ethylenically unsaturated group and is
different from the monomers (a) to (e).
Inventors: |
Kinoshita; Sachiko; ( Tokyo,
JP) ; Yokoyama; Hiromi; (Tokyo, JP) ; Koike;
Takaaki; (Tokyo, JP) ; Miyajima; Koichiro;
(Tokyo, JP) ; Moroishi; Yasuyuki; (Tokyo, JP)
; Ikeda; Shingo; (Tokyo, JP) |
Assignee: |
TOYOCHEM CO., LTD.
Tokyo
JP
TOYO INK SC HOLDINGS CO., LTD.
Tokyo
JP
|
Family ID: |
42828403 |
Appl. No.: |
13/138807 |
Filed: |
April 2, 2010 |
PCT Filed: |
April 2, 2010 |
PCT NO: |
PCT/JP2010/056066 |
371 Date: |
December 23, 2011 |
Current U.S.
Class: |
523/410 ;
524/806; 524/807; 524/831; 524/833 |
Current CPC
Class: |
Y02E 60/13 20130101;
H01M 10/0525 20130101; H01M 4/621 20130101; H01M 2220/30 20130101;
H01M 10/052 20130101; Y02E 60/10 20130101; H01G 11/38 20130101;
H01M 4/13 20130101; H01M 4/622 20130101 |
Class at
Publication: |
523/410 ;
524/806; 524/807; 524/831; 524/833 |
International
Class: |
C08L 33/14 20060101
C08L033/14; C08L 33/06 20060101 C08L033/06; C08L 33/26 20060101
C08L033/26; C08L 43/04 20060101 C08L043/04; C08L 43/02 20060101
C08L043/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 3, 2009 |
JP |
2009-090600 |
Apr 3, 2009 |
JP |
2009-090601 |
Claims
1. A binder composition for a non-aqueous secondary battery
electrode that contains fine particles of a functional
group-containing cross-linkage type resin, wherein the fine
particles of a functional group-containing cross-linkage type resin
are fine particles of the resin obtained by emulsification
polymerization of monomers having an ethylenically unsaturated
group with a radical polymerization initiator in water in the
presence of a surfactant, wherein the monomers having an
ethylenically unsaturated group contains: (A) 0.1 to 20% by weight
of at least one monomer that is selected from the group consisting
of (a) a monomer having one ethylenically unsaturated group per
molecule and also having a monofunctional or polyfunctional epoxy
group, (b) a monomer having one ethylenically unsaturated group per
molecule and also having a monofunctional or polyfunctional amide
group, and (c) a monomer having one ethylenically unsaturated group
per molecule and also having a monofunctional or polyfunctional
hydroxide group; (B) 0.1 to 5% by weight of at least one monomer
that is selected from the group consisting of (d) a monomer having
one ethylenically unsaturated group per molecule and also having a
monofunctional or polyfunctional alkoxysilyl group, and (e) a
monomer having two or more ethylenically unsaturated groups per
molecule; and (C) 75 to 99.8% by weight of (k) a monomer which has
an ethylenically unsaturated group and is different from the
monomers (a) to (e).
2. The binder composition for a non-aqueous secondary battery
electrode according to claim 1, wherein the (k) monomer having an
ethylenically unsaturated group contains at least (m) a monomer
having one ethylenically unsaturated group per molecule and also
having a C.sub.8-18 alkyl group and/or (n) a monomer having one
ethylenically unsaturated group per molecule and also having a
cyclic structure, wherein the monomers (m) and (n) are included in
30 to 95% by weight in sum in total monomers having an
ethylenically unsaturated group ((a) to (e) and (k)).
3. The binder composition for a non-aqueous secondary battery
electrode according to claim 1, containing (D) a non-cross-linked
compound that is selected from the group consisting of a
non-cross-linked epoxy group-containing compound, a
non-cross-linked amide group-containing compound, a
non-cross-linked hydroxide group-containing compound, and a
non-cross-linked oxazoline group-containing compound.
4. A non-aqueous secondary battery electrode, which is obtained by
using the binder composition for a non-aqueous secondary battery
electrode according to claim 1.
5. A non-aqueous secondary battery, which is obtained by using the
non-aqueous secondary battery electrode according to claim 4.
6. A non-aqueous secondary battery according to claim 5, wherein
the non-aqueous secondary battery is a lithium ion secondary
battery.
Description
TECHNICAL FIELD
[0001] The present invention relates to a binder composition for a
non-aqueous secondary battery electrode that has excellent
anti-electrolytic solution property, binding property and
flexibility. Specifically, the present invention relates to a
binder composition for a non-aqueous secondary battery electrode
that can be suitably used for a non-aqueous secondary battery,
specifically a lithium ion secondary battery which has an excellent
charge and discharge cycle property and a high capacity.
BACKGROUND ART
[0002] In recent years, performances of electronic devices have
improved and miniaturization and portabilization of electronic
devices have progressed with the advancement of electronic
technologies, and the demand for a secondary battery having a high
energy density as a power supply has increased. Examples of a
secondary battery include, for example, a nickel hydrogen secondary
battery, a lithium ion secondary battery and the like. For these
secondary batteries, developments of articles having a high
capacity and a high life span are also in progress along with
miniaturization and weight reduction of the devices.
[0003] An electrode of a secondary battery is composed of an
electrode-active material, a conductive auxiliary agent, and
further a binder that attaches them to a current collector. As a
binder resin for a secondary battery, fluorine resins such as
polyvinylidene fluoride and polytetrafluoroethylene were
conventionally used both for a positive electrode and a negative
electrode (non-Patent Literatures 1 and 2). However, a positive
electrode or negative electrode may repeat volume expansion or
contraction at the time of charge and discharge in a secondary
battery, which causes an active material or conductive agent to
drop off, and thus the cycling life of charge and discharge may be
shortened. Therefore, a binder for an electrode is required to have
a cushioning property to resist swelling or contraction of the
electrode. However, the fluorine resin is insufficient in the
cushioning property that allows fitting to the electrode.
Furthermore, a fluorine resin also has poor adhesion to a current
collector or active material, and shows no effects as a binder
unless it is used in a large amount. For this reason, a fluorine
resin could not increase density of an active material in an
electrode, which has inhibited manufacturing a battery electrode
which has a high capacity. Furthermore, a fluorine resin also has
problems that it characteristically dissolves in a specific solvent
such as N-methylpyrrolidone, and that it has a bad influence on the
human body and the environment such as an unusual odor at the time
of manufacturing an electrode and the like.
[0004] Regarding these problems, in Patent Literature 1, a binder
resin is obtained by adding a cross-linking agent to an acrylate
resin dissolved in a solvent, and reacting the resin and the
cross-linking agent in heating and pressing steps at the time of
manufacturing an electrode to obtain a three-dimensional
cross-linking structure body, and this binder resin prevents an
active material or conductive agent from dropping off at the time
of battery charge and discharge. However, with this method,
cross-linking of the three-dimensional cross-linking structure body
obtained by heating and pressure conditions at the time of
manufacture of an electrode is insufficient, variation of
cross-linking also easily occurs, and a sufficient cushioning
property cannot be manifested. Furthermore, in a case where such
binder of solvent-dissolution type is used, if a resin solution is
coated on a substrate of an electrode, and then an organic solvent
is removed, it has the problem that the surface of the
electro-active material is covered with the resin without any
uncovered portion and thus sufficient electrical properties are not
obtained. Furthermore, there were also problems that a process of
manufacturing an electrode requires accuracy and the process
becomes cumbersome and complicated. Furthermore, in recent years,
simplification of processes or saving energy was required due to
the concern about environment and the like. For this reason, a
method is desired which allows short heating treatment processes
with low energy demands at the time of manufacturing an electrode.
In addition, removal of an organic solvent is difficult depending
on the kind of the binder resin, and the problem of odor has not
been solved.
[0005] On the other hand, in Patent Literature 2, an aqueous
cross-linking polymer is used in addition to an organic binder. It
is inferred that kneading of the aqueous cross-linking polymer with
an electrode-active material has the role of a spacer that prevents
aggregation of the electrode-active material, which leads to an
electrode that has an excellent cycling property. To increase this
spacer effect, porous polymer particles, or hollow polymer
particles are used in Patent Literature 2. However, adhesion to an
electrode is insufficient, and thus a binder must be used in a
large amount, which deteriorates battery performances such as an
initial capacity.
[0006] Furthermore, in Patent Literature 3, polymer particles
containing aqueous polymers within the particles are used, which
improves the compatibility of a binder composition or reduces the
leakage to an electrolytic solution, and improves binding force of
a binder. However, this method also leads to insufficient adhesion
to an electrode similarly to the method of Patent Literature 2, and
thus does not improve the cycling life of charge and discharge.
PRIOR ART LITERATURES
Patent Literatures
[0007] Patent Literature 1: Japanese Patent No. 3066682 (Japanese
Patent Application Laid-Open (JP-A) No. 6-96770)
[0008] Patent Literature 2: Japanese Patent No. 3414039 (JP-A No.
8-250124)
[0009] Patent Literature 3: JP-A No. 2000-100436
Non-Patent Literatures
[0010] Non-Patent Literature 1: "Battery Handbook", published by
Denkishoin Co., Ltd., 1980
[0011] Non-Patent Literature 2: "Industrial Material", September
2008 (Vol. 56, No. 9)
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0012] The object of the present invention is to provide a binder
composition for a non-aqueous secondary battery electrode, which
enables production of a non-aqueous secondary battery that has
excellent adhesion to a current collector or electrode, and can
retain a high electric discharge capacity even when charge and
discharge are repeated or under a high-temperature environment
produced as a result of the generation of heat. Furthermore, the
object of the present invention is to provide a non-aqueous
secondary battery electrode, which enables small influence on an
electrode-active material, security of the current collecting
property, improvement of the use efficiency, and the achievement of
charge and discharge cycle property and the high capacity of a
battery, and a non-aqueous secondary battery using the
electrode.
Means for Solving the Problems
[0013] The first invention of the present invention relates to a
binder composition for a non-aqueous secondary battery electrode
that contains fine particles of a functional group-containing
cross-linkage type resin, which is so characterized that the fine
particles of a functional group-containing cross-linkage type resin
are fine particles of a resin obtained by emulsification
polymerization of monomers having an ethylenically unsaturated
group with a radical polymerization initiator in water in the
presence of a surfactant, wherein the monomers having an
ethylenically unsaturated group contain:
[0014] (A) 0.1 to 20% by weight of at least one monomer that is
selected from the group consisting of (a) a monomer having one
ethylenically unsaturated group per molecule and also having a
monofunctional or polyfunctional epoxy group, (b) a monomer having
one ethylenically unsaturated group per molecule and also having a
monofunctional or polyfunctional amide group, and (c) a monomer
having one ethylenically unsaturated group per molecule and also
having a monofunctional or polyfunctional hydroxide group;
[0015] (B) 0.1 to 5% by weight of at least one monomer that is
selected from the group consisting of (d) a monomer having one
ethylenically unsaturated group per molecule and also having a
monofunctional or polyfunctional alkoxysilyl group, and (e) a
monomer having two or more ethylenically unsaturated groups per
molecule; and
[0016] (C) 75 to 99.8% by weight of (k) a monomer which has an
ethylenically unsaturated group and is different from the monomers
(a) to (e).
[0017] Furthermore, the second invention relates to the binder
composition for a non-aqueous secondary battery electrode of the
first invention, which is so characterized that the monomer (k)
having an ethylenically unsaturated group contains at least (m) a
monomer having one ethylenically unsaturated group per molecule and
also having a C.sub.8-18 alkyl group and/or (n) a monomer having
one ethylenically unsaturated group per molecule and also having a
cyclic structure, wherein the monomers (m) and (n) are included in
30 to 95% by weight in sum in total monomers having an
ethylenically unsaturated group ((a) to (e) and (k)).
[0018] Furthermore, the third invention relates to the binder
composition for a non-aqueous secondary battery electrode of the
first or the second invention, which is so characterized by
containing (D) at least one non-cross-linked compound that is
selected from the group consisting of a non-cross-linked epoxy
group-containing compound, a non-cross-linked amide
group-containing compound, a non-cross-linked hydroxide
group-containing compound, and a non-cross-linked oxazoline
group-containing compound.
[0019] Furthermore, the fourth invention relates to a non-aqueous
secondary battery electrode, which is so characterized by being
obtained by using the binder composition for a non-aqueous
secondary battery electrode of any one of the first to third
inventions.
[0020] Furthermore, the fifth invention relates to a non-aqueous
secondary battery, which is so characterized by being obtained by
using the non-aqueous secondary battery electrode of the fourth
invention.
[0021] Furthermore, the sixth invention relates to the non-aqueous
secondary battery of the fifth invention, which is so characterized
that the non-aqueous secondary battery is a lithium ion secondary
battery.
Effects of the Invention
[0022] The binder composition for a non-aqueous secondary battery
electrode of the present invention has excellent anti-electrolytic
solution property, adhesion to a current collector or electrode and
flexibility. By using the binder composition for a non-aqueous
secondary battery electrode of the present invention, it is
possible to provide a non-aqueous secondary battery that has a long
life, and enables the reduction of lowering of electric discharge
capacity in the charge and discharge cycle even with the repetition
of charge and discharge, or under a high-temperature environment
produced as a result of generation of heat.
BEST MODE FOR CARRYING OUT THE INVENTION
<Fine Particles of Functional Group-Containing Cross-Linkage
Type Resin in the Present Invention>
[0023] The binder for a non-aqueous secondary battery electrode of
the present invention is characterized by containing fine particles
of a functional group-containing cross-linkage type resin obtained
by co-polymerization of monomers containing an ethylenically
unsaturated monomer having a specific functional group. The fine
particles of a functional group-containing cross-linkage type resin
can secure an anti-electrolytic solution property by having a
cross-linking structure with specific functional groups, and
furthermore, the fine particles of a functional group-containing
cross-linkage type resin can contribute to the adhesion to a
current collector or electrode by containing the specific
functional groups. Furthermore, by adjusting the amount of the
cross-linking structure or the functional groups, it is possible to
obtain a binder composition for a non-aqueous secondary battery
electrode that has excellent flexibility.
[0024] Furthermore, the cross-linking structure of the fine
particles of a functional group-containing cross-linkage type resin
in the present invention requires a cross-linkage within the
particles. The use of the fine particles of a functional
group-containing cross-linkage type resin for the binder
composition for a non-aqueous secondary battery electrode, of which
the cross-linkage within the particles is suitably adjusted, allows
the binder composition for a non-aqueous secondary battery
electrode to secure an anti-electrolytic solution property. The
cross-linkage of particles to each other (the cross-linkage between
the particles) may also be used in combination for the purpose of
adjusting binder flexibility, but in this case, a cross-linking
agent is added later in many cases, and thus it may lead to the
leakage of an electrolytic solution of the cross-linking agent
component, or the occurrence of variations in the manufacturing of
electrodes. For this reason, the cross-linking agent needs to be
used to an extent of not impairing the anti-electrolytic solution
property.
[0025] The fine particles of a functional group-containing
cross-linkage type resin used in the binder composition for a
non-aqueous secondary battery electrode of the present invention
are fine particles of a resin obtained by the emulsification
polymerization of ethylenically unsaturated monomers with a radical
polymerization initiator in water in the presence of a surfactant.
The fine particles of a functional group-containing cross-linkage
type resin used in the present invention is characterized by being
obtained by the emulsification polymerization of ethylenically
unsaturated monomers comprising the following monomer groups (A),
(B) and (C) in the following proportions.
[0026] (A) 0.1 to 20% by weight of at least one monomer that is
selected from the group consisting of (a) a monomer having one
ethylenically unsaturated group per molecule and also having a
monofunctional or polyfunctional epoxy group, (b) a monomer having
one ethylenically unsaturated group per molecule and also having a
monofunctional or polyfunctional amide group, and (c) a monomer
having one ethylenically unsaturated group per molecule and also
having a monofunctional or polyfunctional hydroxide group;
[0027] (B) 0.1 to 5% by weight of at least one monomer that is
selected from the group consisting of (d) a monomer having one
ethylenically unsaturated group per molecule and also having an
alkoxysilyl group, and (e) a monomer having two or more
ethylenically unsaturated groups per molecule; and
[0028] (C) 75 to 99.8% by weight of (k) a monomer which has an
ethylenically unsaturated group and is different from the monomers
(a) to (e).
<Regarding Group (A) of Monomers>
[0029] Use of the monomers included in the group (A) of the
monomers allows an epoxy group, an amide group, or a hydroxide
group to remain within the particles, or on the surface of the fine
particles of a functional group-containing cross-linkage type
resin, whereby to improve the physical properties such as an
adhesion to a current collector. The monomers included in the group
(A) of the monomers make it easy to cause the functional groups to
remain within the particles or on the surface of the particles even
after synthesis of particles, and have large effects of adhesion to
a current collector even in a small amount. Furthermore, a portion
thereof may be used in cross-linking reaction, and can give a
balance between the anti-electrolytic solution property and the
adhesion by adjusting the cross-linking degree of these functional
groups.
[0030] Examples of the monomer (a) having one ethylenically
unsaturated group per molecule and also having a monofunctional or
polyfunctional epoxy group include, for example, glycidyl
(meth)acrylate, 3,4-epoxy cyclohexyl(meth)acrylate and the
like.
[0031] Examples of the monomer (b) having one ethylenically
unsaturated group per molecule and also having a monofunctional or
polyfunctional amide group include, for example, primary amide
group-containing ethylenically unsaturated monomers such as
(meth)acrylic amide; alkylol(meth)acrylic amides such as N-methylol
acrylic amide, N,N-di(methylol)acrylic amide and
N-methylol-N-methoxymethyl(meth)acrylic amide;
monoalkoxy(meth)acrylic amides such as
N-methoxymethyl-(meth)acrylic amide, N-ethoxymethyl-(meth)acrylic
amide, N-propoxymethyl-(meth)acrylic amide,
N-butoxymethyl-(meth)acrylic amide and
N-pentoxymethyl-(meth)acrylic amide; dialkoxy(meth)acrylic amides
such as N,N-di(methoxymethyl)acrylic amide,
N-ethoxymethyl-N-methoxymethyl methacrylic amide,
N,N-di(ethoxymethyl)acrylic amide, N-ethoxymethyl-N-propoxymethyl
methacrylic amide, N,N-di(propoxymethyl)acrylic amide,
N-butoxymethyl-N-(propoxymethyl)methacrylic amide,
N,N-di(butoxymethyl)acrylic amide,
N-butoxymethyl-N-(methoxymethyl)methacrylic amide,
N,N-di(pentoxymethyl)acrylic amide and
N-methoxymethyl-N-(pentoxymethyl)methacrylic amide;
dialkylamino(meth)acrylic amides such as N,N-dimethylaminopropyl
acrylic amide and N,N-diethylaminopropyl acrylic amide;
dialkyl(meth)acrylic amides such as N,N-dimethyl acrylic amide and
N,N-diethyl acrylic amide; keto group-containing (meth)acrylic
amides such as diacetone(meth)acrylate amide and the like.
[0032] Examples of the monomer (c) having one ethylenically
unsaturated group per molecule and also having a monofunctional or
polyfunctional hydroxide group include, for example,
2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate,
4-hydroxybutyl(meth)acrylate,
2-(meth)acryloyloxyethyl-2-hydroxyethylphthalic acid, glycerol
mono(meth)acrylate, 4-hydroxyvinyl benzene,
1-ethynyl-1-cyclohexanol, allyl alcohol and the like.
[0033] A portion of the functional group of the monomers included
in the group (A) of the monomers may be used in cross-linkage
within the particles by a reaction during the polymerization of the
particles. The present invention is so characterized that the
monomers included in the group (A) of the monomers are used by 0.1
to 20% by weight with respect to the total ethylenically
unsaturated monomers (100% by weight in sum) used in emulsification
polymerization. The monomers included in the group (A) of the
monomers are preferably used by 1 to 15% by weight, and
particularly preferably used by 2 to 10% by weight . If the amount
of the monomers included in the group (A) of the monomers is less
than 0.1% by weight, the amount of functional groups remaining
within the particles or on the surface of the particles after
polymerization becomes less, and cannot contribute sufficiently to
the improvement of an adhesion to a current collector. Furthermore,
if the amount of the monomers included in the group (A) of the
monomers is beyond 20% by weight, it may lead to a problem in
polymerization stability in the emulsification polymerization, or a
problem in the storage stability after polymerization.
<Regarding Group (B) of Monomers>
[0034] The functional groups contained in the monomers included in
the group (B) of the monomers(an alkoxysilyl group, an
ethylenically unsaturated group) are self cross-linkage type
reactive functional groups, and mainly have effects of forming
cross-linkage within the particles in the synthesis of particles.
Sufficient progress of cross-linkages within the particles in the
functional groups contained in monomers included in the group (B)
of the monomers can improve the anti-electrolytic solution
property. Therefore, fine particles of a cross-linkage type resin
can be obtained by using monomers included in the group (B) of the
monomers. Furthermore, sufficient progress of cross-linkages within
the particles in the functional groups contained in monomers
included in the group (B) of the monomers can improve the
anti-electrolytic solution property.
[0035] Examples of the (d) monomer having one ethylenically
unsaturated group per molecule and also having an alkoxysilyl group
include, for example, .gamma.-methacryloxypropyltrimethoxysilane,
.gamma.-methacryloxypropyltriethoxysilane,
.gamma.-methacryloxypropyltributoxysilane,
.gamma.-methacryloxypropylmethyldimethoxysilane,
.gamma.-methacryloxypropylmethyldiethoxysilane,
.gamma.-acryloxypropyltrimethoxysilane,
.gamma.-acryloxypropyltriethoxysilane,
.gamma.-acryloxypropylmethyldimethoxysilane,
.gamma.-methacryloxymethyltrimethoxysilane,
.gamma.-acryloxymethyltrimethoxysilane, vinyltrimethoxysilane,
vinyltriethoxysilane, vinyltributoxysilane,
vinylmethyldimethoxysilane and the like.
[0036] Examples of the monomer (e) having two or more ethylenically
unsaturated groups per molecule include, for example, ethylenically
unsaturated group-containing (meth)acrylic esters such as
allyl(meth)acrylate, 1-methylallyl(meth)acrylate,
2-methylallyl(meth)acrylate, 1-butenyl(meth)acrylate,
2-butenyl(meth)acrylate, 3-butenyl(meth)acrylate,
1,3-methyl-3-butenyl(meth)acrylate, 2-chloroallyl(meth)acrylate,
3-chloroallyl(meth)acrylate, o-allylphenyl(meth)acrylate,
2-(allyloxy)ethyl(meth)acrylate, allyllactyl(meth)acrylate,
citronellyl(meth)acrylate, geranyl(meth)acrylate,
rhodinyl(meth)acrylate, cinnamyl(meth)acrylate, diallyl maleate,
diallyl itaconate, vinyl(meth)acrylate, vinyl crotonate, vinyl
oleate, vinyl linolenate and
2-(2'-vinyloxyethoxy)ethyl(meth)acrylate; polyfunctional
(meth)acrylic esters such as di(meth)acrylate ethylene glycol,
di(meth)acrylate triethylene glycol, di(meth)acrylate tetraethylene
glycol, tri(meth)acrylate trimethylol propane, tri(meth)acrylate
pentaerythritol, 1,1,1-trishydroxymethylethane diacrylate,
triacrylic acid 1,1,1-trishydroxymethylethane and
1,1,1-trishydroxymethylpropane triacrylate; divinyls such as
divinyl benzene and divinyl adipate; diallyls such as diallyl
isophthalate, diallyl phthalate and diallyl maleate, and the
like.
[0037] The alkoxysilyl group or the ethylenically unsaturated group
in the monomer (d) or monomer (e) is used mainly for the purpose of
respective self-condensation during polymerization, or for the
purpose of polymerization to introduce a cross-linking structure
into particles. A portion thereof may also remain within the
particles or on the surface of the particles even after
polymerization. Residual alkoxysilyl groups or ethylenically
unsaturated groups contribute to the cross-linkage between the
particles of the binder composition. In particular, using the
alkoxysilyl group is preferable since it has greater effects that
contribute to the improvement of an adhesion to a current
collector.
[0038] Furthermore, among the monomers included in the group (A) of
the monomers, a N-methylol group included in alkylol(meth)acrylic
amides such as N-methylol acrylic amide, N,N-di(methylol)acrylic
amide and N-methylol-N-methoxymethyl(meth)acrylic amide, or the
like, is also involved with self condensation, and contributes to
cross-linkages within the particles. For this reason, a monomer
having a N-methylol group functions both as the monomers included
within the group (A) of the monomers (improvement of the adhesion),
and as the monomers included within the group (B) of the monomers
(improvement of the anti-electrolytic solution property) in
combination, and thus is preferably used.
[0039] The present invention is so characterized that the monomers
included in the group (B) of the monomers is used by 0.1 to 5% by
weight with respect to the total ethylenically unsaturated monomers
(100% by weight in sum) used in the emulsification polymerization.
The monomers included in the group (B) of the monomers are
preferably used by 0.5 to 3% by weight. If the amount of the
monomers included in the group (B) of the monomers is less than
0.1% by weight, the cross-linkages of the particles may not be
sufficient, and the anti-electrolytic solution property may become
deteriorated. Furthermore, if the amount of the monomers included
in the group (B) of the monomers is beyond 5% by weight, it may
lead to a problem in polymerization stability in the emulsification
polymerization, or a problem in the storage stability after
polymerization.
<Regarding Group (C) of Monomers>
[0040] The fine particles of a functional group-containing
cross-linkage type resin used in the binder composition for the
non-aqueous secondary battery electrode of the present invention
can be obtained by simultaneous emulsification polymerization of
the monomer (k) having an ethylenically unsaturated group as the
group (C) of the monomers, which is different from the monomers (a)
to (e), in addition to the monomers (a) to (e) having one
ethylenically unsaturated group per molecule and also having
various monofunctional or polyfunctional functional groups as
described above.
[0041] This monomer (k) is not particularly limited as long as it
is different from the monomers (a) to (e) and is a monomer having
an ethylenically unsaturated group, and examples thereof include,
for example, a monomer (m) having one ethylenically unsaturated
group per molecule and also having a C.sub.8-18 alkyl group, and a
monomer (n) having one ethylenically unsaturated group per molecule
and also having a cyclic structure, and the like. The monomers (m)
and (n) are preferably included by 30 to 95% by weight in sum with
respect to the total monomers having an ethylenically unsaturated
group ((a) to (e) and (k)) when the monomer (m) and/or monomer (n)
are used in the emulsification polymerization as the monomer (k)
(other monomers may be also contained as the monomer (k)). The
monomer (m) or the monomer (n) is preferably used since the
particle stability at the time of the particle synthesis or the
anti-electrolytic solution property is excellent. If the amount of
the monomers (m) and (n) is less than 30% by weight, it may have a
bad influence on the anti-electrolytic solution property, and if
the amount of the monomers (m) and (n) is beyond 95% by weight, it
may have a bad influence on the stability at the time of the
particle synthesis, or may harm the temporal stability of particles
even after the synthesis.
[0042] Examples of the monomer (m) having one ethylenically
unsaturated group per molecule and also having a C.sub.8-18 alkyl
group include, for example, 2-ethylhexyl(meth)acrylate,
lauryl(meth)acrylate, myristyl(meth)acrylate, cetyl(meth)acrylate,
stearyl(meth)acrylate and the like.
[0043] Examples of the monomer (n) having one ethylenically
unsaturated group per molecule and also having a cyclic structure
include alicyclic ethylenically unsaturated monomers or aromatic
ethylenically unsaturated monomers and the like. Examples of the
alicyclic ethylenically unsaturated monomer include, for example,
cyclohexyl(meth)acrylate, isobonyl(meth)acrylate or the like, and
examples of the aromatic ethylenically unsaturated monomer include,
for example, benzyl(meth)acrylate, phenoxyethyl(meth)acrylate,
styrene, .alpha.-methylstyrene, 2-methylstyrene, chlorostyrene,
allyl benzene, ethynyl benzene and the like.
[0044] Examples of the monomer (k) other than the monomer (m) and
the monomer (n) include, for example, alkyl group-containing
ethylenically unsaturated monomers such as methyl(meth)acrylate,
ethyl(meth)acrylate, propyl(meth)acrylate, n-butyl(meth)acrylate,
pentyl(meth)acrylate and heptyl(meth)acrylate; nitrile
group-containing ethylenically unsaturated monomers such as
(meth)acrylonitrile; C.sub.1-20 perfluoroalkyl group-containing
ethylenically unsaturated monomers such as
perfluoromethylmethyl(meth)acrylate,
perfluoroethylmethyl(meth)acrylate,
2-perfluorobutylethyl(meth)acrylate,
2-perfluorohexylethyl(meth)acrylate,
2-perfluorooctylethyl(meth)acrylate,
2-perfluoroisononylethyl(meth)acrylate,
2-perfluorononylethyl(meth)acrylate,
2-perfluorodecylethyl(meth)acrylate,
perfluoropropylpropyl(meth)acrylate,
perfluorooctylpropyl(meth)acrylate,
perfluorooctylamyl(meth)acrylate and
perfluorooctylundecyl(meth)acrylate; perfluoroalkyl group- or
perfluoroalkyl alkylene-containing ethylenically unsaturated
compounds such as perfluorobutylethylene, perfluorohexylethylene,
perfluorooctylethylene and perfluorodecylethylene; ethylenically
unsaturated compounds having a polyether chain such as polyethylene
glycol(meth)acrylate, methoxypolyethylene glycol(meth)acrylate,
ethoxypolyethylene glycol(meth)acrylate, propoxypolyethylene
glycol(meth)acrylate, n-butoxypolyethylene glycol(meth)acrylate,
n-pentoxypolyethylene glycol(meth)acrylate, phenoxypolyethylene
glycol(meth)acrylate, polypropylene glycol(meth)acrylate,
methoxypolypropylene glycol(meth)acrylate, ethoxypolypropylene
glycol(meth)acrylate, propoxypolypropylene glycol(meth)acrylate,
n-butoxypolypropylene glycol(meth)acrylate, n-pentoxypolypropylene
glycol(meth)acrylate, phenoxypolypropylene glycol(meth)acrylate,
polytetramethyleneglycol(meth)acrylate,
methoxypolytetramethyleneglycol(meth)acrylate, phenoxytetraethylene
glycol(meth)acrylate, hexaethylene glycol(meth)acrylate and
methoxyhexaethylene glycol(meth)acrylate; ethylenically unsaturated
compounds having a polyester chain such as lactone-modified
(meth)acrylate; ethylenically unsaturated compounds containing a
quaternary ammonium base such as (meth)acrylate
dimethylaminoethylmethyl chloride salt,
trimethyl-3-(1-(meth)acrylic amide-1,1-dimethylpropyl)ammonium
chloride, trimethyl-3-(1-(meth)acrylic amide propyl)ammonium
chloride, and trimethyl-3-(1-(meth)acrylic
amide-1,1-dimethylethyl)ammonium chloride; aliphatic vinyl-based
compounds such as vinyl acetate, vinyl butyrate, vinyl propionate,
vinyl hexane, vinyl caprylate, vinyl laurylate, vinyl palmitate and
vinyl stearate; vinyl ether-based ethylenically unsaturated
monomers such as butylvinyl ether and ethylvinyl ether;
.alpha.-olefin-based ethylenically unsaturated monomers such as
1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene and
1-hexadecene; allyl monomers such as allyl acetate and allyl
cyanide; vinyl monomers such as vinyl cyanide, vinyl cyclohexane
and vinyl methyl ketone; ethynyl monomers such as acetylene and
ethynyl toluene and the like.
[0045] Furthermore, examples of the monomer (k) other than the
monomer (m) and the monomer (n) include, for example, carboxyl
group-containing ethylenically unsaturated monomers such as maleic
acid, fumaric acid, itaconic acid, citraconic acid, or alkyl or
alkenyl monoesters thereof, phthalic acid
.beta.-(meth)acryloxyethylmonoester, isophthalic acid
.beta.-(meth)acryloxyethylmonoester, terephthalic acid
.beta.-(meth)acryloxyethylmonoester, succinic acid
.beta.-(meth)acryloxyethylmonoester, acrylic acid, methacrylic
acid, crotonic acid and cinnamic acid; tertiary butyl
group-containing ethylenically unsaturated monomers such as
tertiary butyl(meth)acrylate; sulfonic acid group-containing
ethylenically unsaturated monomers such as vinyl sulfonate and
styrene sulfonate; phosphoric acid group-containing ethylenically
unsaturated monomers such as (2-hydroxyethyl)methacrylate acid
phosphate; keto group-containing ethylenically unsaturated monomers
(a monomer having one ethylenically unsaturated group per molecule
and also having a keto group) such as diacetone(meth)acrylic amide,
acrolein, N-vinyl formamide, vinylmethyl ketone, vinylethyl ketone,
acetoacetoxyethyl(meth)acrylate, acetoacetoxypropyl(meth)acrylate
and acetoacetoxybutyl(meth)acrylate, and the like.
[0046] In a case where the keto group-containing an ethylenically
unsaturated monomer is used as the monomer (k), when a
polyfunctional hydrazide compound having two or more hydrazide
groups, which can react with a keto group as a cross-linking agent,
are mixed with the binder composition, cross-linkage between the
keto group and the hydrazide group create a tough coating film.
This enables the binder composition to have an excellent
anti-electrolytic solution property, and binding property.
Furthermore, since it enables the binder composition to have a
balance between resistance and flexibility under the repetition of
a charge and discharge or a high temperature environment produced
as a result of generation of heat, it is possible to obtain a
non-aqueous secondary battery that has a long life, and enables the
reduction of lowering the electric discharge capacity in the charge
and discharge cycle.
[0047] When the keto group-containing an ethylenically unsaturated
monomer is used in emulsification polymerization, the monomer is
recommended to be included by 0.1 to 10% by weight with respect to
the total monomers having an ethylenically unsaturated group ((a)
to (e) and (k)) (100% by weight in sum). The keto group-containing
ethylenically unsaturated monomer is preferably included by 1 to 8%
by weight, and ideally included by 3 to 7% by weight. If the amount
of the keto group-containing ethylenically unsaturated monomer is
less than 0.1% by weight, cross-linkages of the fine particles of
the resin may not be sufficient, and may not contribute to the
anti-electrolytic solution property. Furthermore, if the amount of
the keto group-containing ethylenically unsaturated monomer is
beyond 10% by weight, the stability after addition of the
cross-linking agent may become deteriorated.
[0048] As the keto group-containing an ethylenically unsaturated
monomer, diacetone(meth)acrylic amide is particularly ideal since
it has a function of the monomer (b) having one ethylenically
unsaturated group per molecule and also has a monofunctional or
polyfunctional amide group as described above.
[0049] Examples of a polyfunctional hydrazide compound include, for
example, aliphatic dihydrazide such as oxalic acid dihydrazide,
malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid
dihydrazide, adipic acid dihydrazide and sebacic acid dihydrazide,
and in addition, carbonic acid polyhydrazide, aliphatic, alicyclic
or aromatic bis-semicarbazide, aromatic dicarboxylic acid
dihydrazide, polyacrylic acid polyhydrazide, aromatic hydrocarbon
dihydrazide, hydrazine-pyridine derivatives and unsaturated
dicarboxylic acid dihydrazide such as maleic acid dihydrazide, and
the like. Furthermore, Ajicure VDH (manufactured by Ajinomoto
Fine-Techno Co., Inc.) or the like may be also used. Such a
polyfunctional hydrazide compound is added preferably in 0.1 to 10
parts by weight, and ideally in 1 to 5 parts by weight relative to
100 parts by weight of the solid content of the fine particles of a
functional group-containing cross-linkage type resin.
[0050] The cross-linking reaction of a keto group in the fine
particles of a functional group-containing cross-linkage type
resin, with the hydrazide group in the polyfunctional hydrazide
compound, may be carried out with heating treatment if necessary in
manufacturing an electrode for the purpose of strengthening the
cross-linkages and adjusting the binder performances. For example,
the heating treatment is preferably conducted at 40.degree. C. to
200.degree. C.
[0051] Furthermore, among the monomers (k), ethylenically
unsaturated monomers having a carboxyl group, a tertiary butyl
group (which becomes a carboxyl group by leaving of tertiary
butanol by heat.), a sulfonic acid group or a phosphoric acid group
can be preferably used since the fine particles of a resin obtained
by co-polymerization of the ethylenically unsaturated monomer
having a carboxyl group, a tertiary butyl group, a sulfonic acid
group or a phosphoric acid group have the effects of having
residual functional groups as mentioned above within the particles
or on the surface of the particles even after polymerization, which
effectively improves physical properties such as an adhesion to a
current collector and at the same time, effectively prevents
aggregation in the synthesis, and effectively of retains particle
stability after the synthesis.
[0052] A portion of the carboxyl group, the tertiary butyl group,
the sulfonic acid group, and the phosphoric acid group may react
during the polymerization and be used in the cross-linkages within
the particles. When the monomer containing a carboxyl group, a
tertiary butyl group, a sulfonic acid group, and a phosphoric acid
group is used, the monomer is included preferably in 0.1 to 10% by
weight, and ideally in 1 to 5% by weight with respect to the total
ethylenically unsaturated monomers (100% by weight in sum) used in
the emulsification polymerization. If the amount of the monomer
containing a carboxyl group, a tertiary butyl group, a sulfonic
acid group, and a phosphoric acid group is less than 0.1% by
weight, the stability of particles may become deteriorated. In
addition, if the amount of the monomer containing a carboxyl group,
a tertiary butyl group, a sulfonic acid group, and a phosphoric
acid group is beyond 10% by weight, the hydrophilicity of the
binder composition becomes too strong and the anti-electrolytic
solution property may become deteriorated. Furthermore, these
functional groups may react during drying and be used in the
cross-linkages within particles or between particles.
[0053] For example, a carboxyl group may react with an epoxy group
during polymerization and drying to introduce a cross-linking
structure into the fine particles of the resin. Similarly, a
tertiary butyl group may also react with an epoxy group similarly
since it produces tertiary butyl alcohol and forms a carboxyl group
if heated to a constant temperature or higher.
[0054] These monomers (k) can be used in two or more kinds of the
monomers described above in combination for the purpose of
adjusting the stability of particles during polymerization or the
glass transition temperature, further the film formability or the
physical properties of a coating film. Furthermore, for example, in
combination with (meth)acrylonitrile or the like these monomers
have the effects of manifesting rubber elasticity.
<Method for Production of Fine Particles of a Functional
Group-Containing Cross-Linkage Type Resin>
[0055] The fine particles of a functional group-containing
cross-linkage type resin of the present invention are synthesized
by a conventional known emulsification polymerization method.
<Emulsifying Agent Used in Emulsification Polymerization>
[0056] As an emulsifying agent used at the time of emulsification
polymerization in the present invention, any conventional known
emulsifying agent such as a reactive emulsifying agent having an
ethylenically unsaturated group or a non-reactive emulsifying agent
having no ethylenically unsaturated group, or the like, may be
used.
[0057] The reactive emulsifying agent having an ethylenically
unsaturated group is further broadly divided, for example into
anionic emulsifying agents and nonionic emulsifying agents.
Particularly, if an anionic reactive emulsifying agent or nonionic
reactive emulsifying agent having an ethylenically unsaturated
group is preferably used since the diameters of dispersion
particles of a copolymer become fine and the particle size
distribution becomes narrow, the anti-electrolytic solution
property improves when it is used as a binder for a non-aqueous
secondary battery electrode. This anionic reactive emulsifying
agent or nonionic reactive emulsifying agent having an
ethylenically unsaturated group may be used alone, or may be used
in a mixture of two or more kinds.
[0058] Example of an anionic reactive emulsifying agent having an
ethylenically unsaturated group includes specific examples
described below, but an emulsifying agent that can be used in the
invention of the present application is not limited thereto.
[0059] Examples of an emulsifying agent include alkyl ether-based
emulsifying agents (as commercialized products, for example,
Acualon KH-05, KH-10 and KH-20 manufactured by DAI-ICHI KOGYO
SEIYAKU CO., LTD., ADEKA REASOAP SR-10N and SR-20N manufactured by
ADEKA CORPORATION, LATEMUL PD-104 manufactured by Kao Corporation
or the like); sulfosuccinic acid ester-based emulsifying agents (as
commercialized products, for example, LATEMUL S-120, S-120A, S-180P
and S-180A manufactured by Kao Corporation, ELEMINOL JS-2
manufactured by Sanyo Chemical Industries, Ltd., or the like);
alkylphenyl ether-based or alkylphenyl ester-based emulsifying
agents (as commercialized products, for example, Acualon H-2855A,
H-3855B, H-3855C, H-3856, HS-05, HS-10, HS-20 and HS-30
manufactured by DAI-ICHI KOGYO SEIYAKU CO., LTD., ADEKA REASOAP
SDX-222, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N and SE-20N
manufactured by ADEKA CORPORATION, or the like); (meth)acrylate
sulfuric acid ester-based emulsifying agents (as commercialized
products, for example, Antox MS-60 and MS-2N manufactured by Nippon
Nyukazai Co, Ltd., ELEMINOL RS-30 manufactured by Sanyo Chemical
Industries, Ltd. or the like); phosphoric acid ester-based
emulsifying agents (as commercialized products, for example,
H-3330PL manufactured by DAI-ICHI KOGYO SEIYAKU CO., LTD., ADEKA
REASOAP PP-70 manufactured by ADEKA CORPORATION or the like), and
the like.
[0060] Examples of a nonionic-based reactive emulsifying agent that
can be used in the present invention include, for example, alkyl
ether-based emulsifying agents (as commercialized products, for
example, ADEKA REASOAP ER-10, ER-20, ER-30 and ER-40 manufactured
by ADEKA CORPORATION, LATEMUL PD-420, PD-430 and PD-450
manufactured by Kao Corporation or the like); alkylphenyl
ether-based or alkylphenyl ester-based emulsifying agents (as
commercialized products, for example, Acualon RN-10, RN-20, RN-30
and RN-50 manufactured by DAI-ICHI KOGYOSEIYAKU CO., LTD., ADEKA
REASOAP NE-10, NE-20, NE-30 and NE-40 manufactured by ADEKA
CORPORATION or the like); (meth)acrylate sulfuric acid ester-based
emulsifying agents (as commercialized products, for example,
RMA-564, RMA-568 and RMA-1114 manufactured by Nippon Nyukazai Co,
Ltd. or the like) and the like.
[0061] A non-reactive emulsifying agent which has no ethylenically
unsaturated group may be used in combination if necessary with the
reactive emulsifying agent having an ethylenically unsaturated
group at the time of obtaining the fine particles of a functional
group-containing cross-linkage type resin of the present invention
by emulsification polymerization. The non-reactive emulsifying
agent can be broadly divided into a non-reactive anionic-based
emulsifying agent and a non-reactive nonionic-based emulsifying
agent.
[0062] Examples of a non-reactive nonionic-based emulsifying agent
include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl
ether and polyoxyethylene stearyl ether; polyoxyethylene
alkylphenyl ethers such as polyoxyethylene octylphenyl ether and
polyoxyethylene nonylphenyl ether; sorbitan-higher aliphatic acid
esters such as sorbitan monolaurate, sorbitan monostearate and
sorbitan trioleate; polyoxyethylene sorbitan-higher aliphatic acid
esters such as polyoxyethylene sorbitan monolaurate;
polyoxyethylene-higher aliphatic acid esters such as
polyoxyethylene monolaurate and polyoxyethylene monostearate;
glycerin-higher aliphatic acid esters such as oleic acid
monoglyceride and stearic acid monoglyceride;
polyoxyethylene/polyoxypropylene/block copolymers, polyoxyethylene
distyrene-modified phenyl ethers and the like.
[0063] Furthermore, examples of a non-reactive anionic-based
emulsifying agent include higher aliphatic acid salts such as
sodium oleate; alkylarylsulfonic acid salts such as sodium
dodecylbenzenesulfonate; alkyl sulfuric acid ester salts such as
sodium lauryl sulfate; polyoxyethylene alkyl ether sulfuric acid
ester salts such as sodium polyoxyethylene lauryl ether sulfate;
polyoxyethylene alkylaryl ether sulfuric acid ester salts such as
sodium polyoxyethylene nonylphenyl ether sulfate;
alkylsulfosuccinic acid ester salts and derivatives thereof such as
sodium monooctylsulfosuccinate, sodium dioctylsulfosuccinate and
sodium polyoxyethylene laurylsulfosuccinate; polyoxyethylene
distyrene-modified phenyl ether sulfuric acid ester salts and the
like.
[0064] The amount of the emulsifying agent used in the present
invention is not necessarily limited, but may be appropriately
selected depending on the required physical properties when the
fine particles of a functional group-containing cross-linkage type
resin are used finally as a binder for a non-aqueous secondary
battery electrode. For example, the emulsifying agent is used
usually within a range of 0.1 to 30 parts by weight, preferably 0.3
to 20 parts by weight, and ideally 0.5 to 10 parts by weight,
relative to 100 parts by weight of the ethylenically unsaturated
monomers in sum.
[0065] Aqueous protective colloid may be used in combination in
emulsification polymerization of the fine particles of a functional
group-containing cross-linkage type resin of the present invention.
Examples of the aqueous protective colloid include, for example,
polyvinyl alcohols such as partially saponified polyvinyl alcohol,
completely saponified polyvinyl alcohol and modified polyvinyl
alcohol; cellulose derivatives such as hydroxyethyl cellulose,
hydroxypropyl cellulose and carboxymethyl cellulose salt; natural
polysaccharides such as Guar gum, or the like, and these may be
used alone, or used in combination of multiple kinds. The use
amount of the aqueous protective colloid is 0.1 to 5 parts by
weight, and further preferably 0.5 to 2 parts by weight per 100
parts by weight of the ethylenically unsaturated monomers in
sum.
<Aqueous Medium Used in Emulsification Polymerization>
[0066] Examples of an aqueous medium used in emulsification
polymerization of the fine particles of a functional
group-containing cross-linkage type resin of the present invention
include water, and a hydrophilic organic solvent can be used within
a range of not impairing the purposes of the present invention.
<Polymerization Initiator Used in Emulsification
Polymerization>
[0067] The polymerization initiator used in obtaining the fine
particles of a functional group-containing cross-linkage type resin
of the present invention is not particularly limited as long as the
polymerization initiator has the ability of initiating radical
polymerization, and known oil-soluble polymerization initiators or
aqueous polymerization initiators may be used.
[0068] An oil-soluble polymerization initiator is not particularly
limited, but examples of the oil-soluble polymerization initiator
include, for example, organic peroxides such as benzoyl peroxide,
tert-butylperoxybenzoate, tert-butylhydroperoxide,
tert-butylperoxy(2-ethylhexanoate),
tert-butylperoxy-3,5,5-trimethylhexanoate and
di-tert-butylperoxide; azobis compounds such as
2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile,
2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) and
1,1'-azobis-cyclohexane-1-carbonitrile, and the like. These may be
used as one kind or in a mixture of two or more kinds. These
polymerization initiators are preferably used in an amount of 0.1
to 10.0 parts by weight relative to 100 parts by weight of the
ethylenically unsaturated monomers.
[0069] In the present invention, an aqueous polymerization
initiator is preferably used, and a conventional known aqueous
polymerization initiator, for example, ammonium persulfate,
potassium persulfate, hydrogen peroxide,
2,2'-azobis(2-methylpropionate amidine)dihydrochloride or the like
may be suitably used. Furthermore, in conduction of the
emulsification polymerization, a reduction agent may be used in
combination with the polymerization initiator if desired. By using
a reduction agent, the emulsification polymerization rate may be
promoted, or emulsification polymerization at a low temperature may
be easily carried out. Examples of such a reduction agent include,
for example, reductive organic compounds such as metal salts, e.g.,
ascorbic acid, erythorbic acid, tartaric acid, citric acid, glucose
and sodium formaldehyde sulfoxylate, and reductive inorganic
compounds such as thiosulfate, sodium sulfite, sodium hydrosulfite
and sodium methabisulfite, ferrous chloride, Rongalit, thiourea
dioxide and the like. These reduction agents are preferably used in
an amount of 0.05 to 5.0 parts by weight relative to 100 parts by
weight of the total ethylenically unsaturated monomers.
<Conditions for Emulsification Polymerization>
[0070] Furthermore, polymerization may be also carried out by a
photochemical reaction or exposure to radiation or the like without
the polymerization initiator. The polymerization temperature is set
to be higher than the temperature of polymerization initiation of
the respective polymerization initiator. For example, for a
peroxide-based polymerization initiator, the polymerization
temperature is usually set to be 70.degree. C. or so. The
polymerization time is not particularly limited, but is usually
between 2 to 24 hours.
<Other Materials Used in Reaction>
[0071] Furthermore, a buffering agent may be used in a suitable
amount, such as sodium acetate, sodium citrate, sodium
hydrocarbonate or the like, and furthermore, a chain transfer agent
may be used such as mercaptans, e.g., octyl mercaptan, 2-ethylhexyl
thioglycolate, octyl thioglycolate, stearyl mercaptan, lauryl
mercaptan, t-dodecyl mercaptan if necessary.
[0072] When a monomer having an acidic functional group such as a
carboxyl group-containing an ethylenically unsaturated monomer is
used in the polymerization of the fine particles of a functional
group-containing cross-linkage type resin, the monomer may be
neutralized with a basic compound before or after the
polymerization. In the neutralization, the acidic functional group
may be neutralized with a base such as alkylamines such as ammonia
or trimethylamine, triethylamine and butylamine; alcohol amines
such as 2-dimethylaminoethanol, diethanolamine, triethanolamine and
aminomethylpropanol; and morpholine. However, a base which has good
effects for dryness is a base which has high volatilization, and it
is preferable that the base be aminomethyl propanol or ammonia.
<Properties of Fine Particles of a Functional Group-Containing
Cross-Linkage Type Resin>
<Glass Transition Temperature>
[0073] Furthermore, the glass transition temperature (hereinafter,
it may be referred to as Tg) of the fine particles of a functional
group-containing cross-linkage type resin is preferably -30 to
70.degree. C., and ideally -20 to 30.degree. C. If Tg is lower than
-30.degree. C., the binder coats the electrode-active material too
much, and easily increases the impedance. Furthermore, if Tg is
beyond 70.degree. C., the flexibility and viscosity of the binder
may become deficient, and an adhesion to a current collecting
material of the electrode-active material, and the formability of
an electrode may become inferior. Furthermore, the glass transition
temperature is a value determined using differential scanning
calorimetry (DSC).
[0074] Measurement of the glass transition temperature by
differential scanning calorimetry (DSC) may be carried out as
described below. About 2 mg of a resin obtained by drying the fine
particles of a functional group-containing cross-linkage type resin
was weighed on an aluminum pan, and a vessel for the test was set
to a DSC measurement holder, and endothermic peaks of charts
obtained at 10.degree. C./min heating conditions were read. The
peak temperature at this time is designated as the glass transition
temperature of the present invention.
<Structure of Particle>
[0075] Furthermore, in the present invention, the particle
structure of the fine particles of a functional group-containing
cross-linkage type resin may be made as a multilayer structure,
so-called core-shell particles. For example, a resin, which is
obtained mainly by the polymerization of monomers having a
functional group, is localized to the core part, or the shell part,
or difference in Tg or composition is set by the core or shell,
whereby to improve the curability, dryness, film formability or
mechanical strength of the binder.
<Diameter of Particles>
[0076] The average particle diameter of the fine particles of a
functional group-containing cross-linkage type resin is preferably
10 to 500 nm, and ideally 30 to 250 nm from a point of adhesion to
an electrode-active material or the stability of particles.
Furthermore, if coarse large particles having a diameter of 1 .mu.m
or greater are largely contained, stability of particles is harmed,
and thus coarse large particles having a diameter of 1 .mu.m or
greater are preferably no more than 5% by weight or less.
Furthermore, the average particle diameter in the present invention
refers to a volume average particle diameter, and can be measured
by a dynamic light scattering method.
[0077] Measurement of the average particle diameter by the dynamic
light scattering method can be carried out as described below.
Dispersion liquid of the fine particles of a functional
group-containing cross-linkage type resin is diluted with water to
200 to 1000 folds with respect to the solid content. About 5 ml of
the diluted liquid is injected into a cell of a measurement
apparatus [MICRO TRAK manufactured by NIKKISO, CO., LTD.], and
conditions for a solvent according to a sample (water in the
present invention) and refractive index of a resin are input, and
then the measurement is carried out. The peak of the volume
particle diameter distribution data (histogram) obtained at this
time is designated as the average particle diameter of the present
invention.
<Strength and Elongation Rate of a Coating Film>
[0078] Furthermore, the strength and the elongation rate of a
coating film obtained by film-forming the fine particles of a
functional group-containing cross-linkage type resin are preferably
1.0 to 7.0 N/mm.sup.2 of the strength and 300% to 2000% of the
elongation rate, and ideally 2.0 to 5.5 N/mm.sup.2 of the strength
and 400% to 1200% of the elongation rate from a point of toughness
of the resin. If the strength is less than 1.0 N/mm.sup.2, the
retaining force for the active material or an adhesion force to a
current collector may become deteriorated. Furthermore, if the
strength is beyond 7.0 N/mm.sup.2, the coating film becomes too
rigid, and thus the adhesion force may become deteriorated. If the
elongation rate is less than 300%, the coating film becomes weak,
and the sufficient adhesion force may not be obtained. Furthermore,
if the elongation rate is beyond 2000%, the retaining force of an
active material or an adhesion force to a current collector may
become deteriorated. Furthermore, the strength and the elongation
rate of the coating film in the present invention mean the rupture
strength and the rupture degree of elongation measured by
Tensilon.
[0079] The measurement of the strength and the elongation rate of
the coating film by Tensilon may be carried out by a method
described below. The fine particles of a functional
group-containing cross-linkage type resin are dried, to manufacture
a sheet having about 0.5 mm thickness. Test species for the
measurement are cutout to 5 mm.times.60 mm, and the film thickness
is exactly measured. The measurement is carried out under the
conditions of constant levels of 23.degree. C. temperature and 50%
humidity by a tensile tester [ORIENTEC, Co., Ltd. manufactured by
Tensilon] and at a constant distance between chucks of 20 mm at a
tensile rate of 50 mm/min. The rupture strength and the rupture
elongation rate, which are calculated from the rupture strength and
the rupture set obtained by the measurements in consideration of
the film thickness, are designated as the strength and the
elongation rate of the present invention.
<Gel Fraction>
[0080] Furthermore, the gel fraction of a coating film obtained by
film-forming the fine particles of a functional group-containing
cross-linkage type resin of the present invention is preferably 50%
or more, further 70% or more. The gel fraction refers to the
content of a resin retaining its shape without dissolution in an
organic solvent after the immersion of the coating film obtained by
film-forming the fine particles of the resin in the organic solvent
(herein, the organic solvent refers to a universally used solvent
such as methanol, ethanol, ethyl acetate, methylethyl ketone,
toluene and cyclohexane, or solvents used as a secondary battery
electrolytic solution such as propylene carbonate and ethyl
carbonate, and the like) for a constant time.
[0081] Usually, measurement of the gel fraction of the resin may be
carried out by a method described below. The fine particles of a
functional group-containing cross-linkage type resin are dried, and
about 0.2 g of a test species is manufactured. A test species for
measurement is cutout to 2 cm.times.2 cm, and the weight is exactly
measured. Propylene carbonate is chosen as an organic solvent for
the measurement of gel fraction in this investigation. The test
species is immersed in the organic solvent, and then left to stand
at 70.degree. C. for 24 hours, whereby to immerse the test species
sufficiently in the organic solvent. After the immersion, the
organic solvent remaining in the test species is completely removed
with oven dry, and the weight change is measured. From the weight
change before and after the immersion, the resin content insoluble
in the organic solvent is calculated, and is designated as the gel
fraction of the present invention.
<Non-Cross-Linked Compound (D) Added to Polymerized Fine
Particles of Resin>
[0082] The binder composition for the non-aqueous secondary battery
electrode of the present invention preferably contains a
non-cross-linked compound (D) that is selected from a group
consisting of a non-cross-linked epoxy group-containing compound, a
non-cross-linked amide group-containing compound, a
non-cross-linked hydroxide group-containing compound, and a
non-cross-linked oxazoline group-containing compound [hereinafter,
it may be referred to as the compound (D)] in addition to the fine
particles of a functional group-containing cross-linkage type
resin.
[0083] The "non-cross-linked functional group-containing compound",
which is the compound (D), is different from a compound which forms
the internal cross-linking structure of the fine particles of a
functional group-containing cross-linkage type resin
(three-dimensional cross-linkage structure) such as the monomers
included in the group (B) of the monomers of the present invention,
and refers to a compound that is added after the emulsification
polymerization of the fine particles of the resin (formation of the
polymer) (not involved with formation of internal cross-linking
structure of the fine particles of the resin). That is, the
"non-cross-linked" means that a compound is not involved with the
formation of internal cross-linking structure of the fine particles
of a functional group-containing cross-linkage type resin of the
present invention.
[0084] The cross-linking structure possessed by the fine particles
of a functional group-containing cross-linkage type resin secures
anti-electrolytic solution property. Furthermore, with use of the
compound (D), at least one functional group that is selected from
an epoxy group, an amide group, a hydroxide group, and an oxazoline
group in the compound (D) can contribute to an adhesion to a
current collector or electrode. Furthermore, by adjusting the
amount of the cross-linking structure or the functional group, it
is possible to obtain a binder composition for a non-aqueous
secondary battery electrode that has excellent flexibility.
[0085] Furthermore, the fine particles of a functional
group-containing cross-linkage type resin in the present invention
need to be cross-linked within the particles. By suitably adjusting
the cross-linkages within the particles, it is possible to secure
the anti-electrolytic solution property. Furthermore, by adding the
non-cross-linked compound (D) that is selected from the group
consisting of a non-cross-linked epoxy group-containing compound, a
non-cross-linked amide group-containing compound, a
non-cross-linked hydroxide group-containing compound, and a
non-cross-linked oxazoline group-containing compound to the fine
particles of a functional group-containing cross-linkage type
resin, the epoxy group, the amide group, the hydroxide group or the
oxazoline group works on a current collector, whereby to
effectively improve an adhesion to a current collector or
electrode. The functional groups included in the compound (D) are
stable for a long storage, or stable against heat at the time of
manufacturing an electrode, and thus have great effects of
improving adhesion to a current collector even in use of a small
amount. Furthermore, the functional groups included in the compound
(D) are also excellent in storage stability. The compound (D) may
be reacted with a functional group in the fine particles of a
functional group-containing cross-linkage type resin for the
purpose of adjusting the flexibility or the anti-electrolytic
solution property of the binder. However, if the functional group
in the compound (D) is used too much for the purpose of the
reaction with the functional group in the fine particles of a
functional group-containing cross-linkage type resin, functional
groups that can work mutually on a current collector or electrode
are reduced. For this reason, the reaction of the fine particles of
a functional group-containing cross-linkage type resin with the
compound (D) should not impair an adhesion to a current collector
or electrode. Furthermore, when a portion of the functional groups
included in the compound (D) is used in the cross-linking reaction
[when the compound (D) is a polyfunctional compound], it is
possible to give a balance between the anti-electrolytic solution
property and the adhesion by adjusting the cross-linkage degree of
these functional groups.
<Non-Cross-Linked Epoxy Group-Containing Compound>
[0086] Examples of the non-cross-linked epoxy group-containing
compound include, for example, epoxy group-containing ethylenically
unsaturated monomers such as glycidyl(meth)acrylate and 3,4-epoxy
cyclohexyl(meth)acrylate; radical polymerization-based resins
obtained by polymerization of ethylenically unsaturated monomers
comprising the epoxy group-containing ethylenically unsaturated
monomers; polyfunctional epoxy compounds such as ethylene glycol
diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin
diglycidyl ether, glycerin triglycidyl ether,
1,6-hexanedioldiglycidyl ether, trimethylol propane triglycidyl
ether, diglycidyl aniline, N,N,N',N'-tetraglycidyl-m-xylylene
diamine and 1,3-bis(N,N'-diglycidyl aminomethyl)cyclohexane;
epoxy-based resins such as bisphenol A-epichlorohydrin type epoxy
resin and bisphenol F-epichlorohydrin type epoxy resin, and the
like.
[0087] Among the epoxy group-containing compounds, epoxy-based
resins such as bisphenol A-epichlorohydrin type epoxy resin and
bisphenol F-epichlorohydrin type epoxy resin or a radical
polymerization-based resin obtained by polymerization of
ethylenically unsaturated monomers comprising epoxy
group-containing ethylenically unsaturated monomers is particularly
preferable. The epoxy-based resin can be expected to have
synergetic effects of improving the anti-electrolytic solution
property with the bisphenol skeleton, and improving the adhesion to
a current collector by a hydroxide group included in the skeleton.
Furthermore, the radical polymerization-based resin obtained by
polymerization of ethylenically unsaturated monomers comprising
epoxy group-containing ethylenically unsaturated monomers can be
expected to have effects of improving the adhesion to a current
collector by having many epoxy groups in the resin skeleton and
improving the anti-electrolytic solution property due to the fact
of being a resin when compared to monomers.
<Non-Cross-Linked Amide Group-Containing Compound>
[0088] Examples of the non-cross-linked amide group-containing
compound include, for example, ethylenically unsaturated monomers
comprising amide group-containing ethylenically unsaturated
monomers, such as: primary amide group-containing compounds such as
(meth)acrylic amide; alkylol(meth)acrylic amide-based compounds
such as N-methylol acrylic amide, N,N-di(methylol)acrylic amide and
N-methylol-N-methoxymethyl(meth)acrylic amide;
monoalkoxy(meth)acrylic amide-based compounds such as
N-methoxymethyl-(meth)acrylic amide, N-ethoxymethyl-(meth)acrylic
amide, N-propoxymethyl-(meth)acrylic amide,
N-butoxymethyl-(meth)acrylic amide and
N-pentoxymethyl-(meth)acrylic amide; dialkoxy(meth)acrylic
amide-based compounds such as N,N-di(methoxymethyl)acrylic amide,
N-ethoxymethyl-N-methoxymethyl methacrylic amide,
N,N-di(ethoxymethyl)acrylic amide, N-ethoxymethyl-N-propoxymethyl
methacrylic amide, N,N-di(propoxymethyl)acrylic amide,
N-butoxymethyl-N-(propoxymethyl)methacrylic amide,
N,N-di(butoxymethyl)acrylic amide,
N-butoxymethyl-N-(methoxymethyl)methacrylic amide,
N,N-di(pentoxymethyl)acrylic amide and
N-methoxymethyl-N-(pentoxymethyl)methacrylic amide;
dialkylamino(meth)acrylic amide-based compounds such as
N,N-dimethylaminopropyl acrylic amide and N,N-diethylaminopropyl
acrylic amide; dialkyl(meth)acrylic amide-based compounds such as
N,N-dimethyl acrylic amide and N,N-diethyl acrylic amide; keto
group-containing (meth)acrylic amide-based compounds such as
diacetone (meth)acrylic amide, or the like, radical
polymerization-based resins obtained by polymerization of amide
group-containing ethylenically unsaturated monomers; and the
like.
[0089] Among the amide group-containing compounds, the radical
polymerization-based resin obtained by the polymerization of
ethylenically unsaturated monomers comprising amide
group-containing ethylenically unsaturated monomers such as acrylic
amide is particularly preferable. The radical polymerization-based
resin obtained by the polymerization of ethylenically unsaturated
monomers comprising amide group-containing ethylenically
unsaturated monomers can be expected to have effects of improving
the adhesion to a current collector by having more amide groups in
the resin skeleton and improving the anti-electrolytic solution
property due to the fact of being a resin when compared to
monomers.
<Non-Cross-Linked Hydroxide Group-Containing Compound>
[0090] Examples of the non-cross-linked hydroxide group-containing
compound include, for example, hydroxide group-containing
ethylenically unsaturated monomers such as
2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate,
4-hydroxybutyl(meth)acrylate, glycerol mono(meth)acrylate,
4-hydroxyvinyl benzene, 1-ethynyl-1-cyclohexanol and allyl alcohol;
radical polymerization-based resins obtained by polymerization of
ethylenically unsaturated monomers comprising the hydroxide
group-containing ethylenically unsaturated monomers;
straight-chained aliphatic diols such as ethylene glycol,
diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol
and 1,6-hexanediol; branched-chained aliphatic diols such as
propylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol and
2,2-diethyl-1,3-propanediol; cyclic diols such as
1,4-bis(hydroxymethyl)cyclohexane, and the like.
[0091] Among the hydroxide group-containing compounds, the radical
polymerization-based resin obtained by polymerization of
ethylenically unsaturated monomers comprising the hydroxide
group-containing ethylenically unsaturated monomer, or cyclic diols
are particularly preferable. The radical polymerization-based resin
obtained by polymerization of ethylenically unsaturated monomers
comprising the hydroxide group-containing ethylenically unsaturated
monomers can be expected to have effects of improving the adhesion
to a current collector by having more hydroxide groups in the resin
skeleton and improving the anti-electrolytic solution property due
to the fact of being a resin when compared to monomers.
Furthermore, cyclic diols can be expected to have effects of
improving the anti-electrolytic solution property by having a
cyclic structure in the skeleton.
<Non-Cross-Linked Oxazoline Group-Containing Compound>
[0092] Examples of the non-cross-linked oxazoline group-containing
compound include, for example, 2'-methylene bis(2-oxazoline),
2,2'-ethylene bis(2-oxazoline), 2,2'-ethylene
bis(4-methyl-2-oxazoline), 2,2'-propylene bis(2-oxazoline),
2,2'-tetramethylene bis(2-oxazoline), 2,2'-hexamethylene
bis(2-oxazoline), 2,2'-octamethylene bis(2-oxazoline),
2,2'-p-phenylene bis(2-oxazoline), 2,2'-p-phenylene
bis(4,4'-dimethyl-2-oxazoline), 2,2'-p-phenylene
bis(4-methyl-2-oxazoline), 2,2'-p-phenylene
bis(4-phenyl-2-oxazoline), 2,2'-m-phenylene bis(2-oxazoline),
2,2'-m-phenylene bis(4-methyl-2-oxazoline), 2,2'-m-phenylene
bis(4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylene bis(4-phenylene
bis-2-oxazoline), 2,2'-o-phenylene bis(2-oxazoline),
2,2'-o-phenylene bis(4-methyl-2-oxazoline), 2,2'-bis(2-oxazoline),
2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(4-ethyl-2-oxazoline),
2,2'-bis(4-phenyl-2-oxazoline), and further oxazoline
group-containing radical polymerization-based resins, and the
like.
[0093] Among the oxazoline group-containing compounds,
particularly, the phenylene bis-type oxazoline compound such as
2'-p-phenylene bis(2-oxazoline), or the radical
polymerization-based resin obtained by polymerization of
ethylenically unsaturated monomers comprising oxazoline
group-containing ethylenically unsaturated monomers are preferable.
The phenylene bis-type oxazoline compound has effects of improving
the anti-electrolytic solution property by having a phenyl group in
the skeleton. Furthermore, the radical polymerization-based resin
obtained by polymerization of ethylenically unsaturated monomers
comprising oxazoline group-containing ethylenically unsaturated
monomers can improve the adhesion to a current collector by having
more oxazoline groups in the resin skeleton, and furthermore, can
improve the anti-electrolytic solution property resin due to the
fact of being a resin when compared to monomers.
<Addition Amount and Molecular Weight of Compound (D)>
[0094] The compound (D) is added preferably in an amount of 0.1 to
50 parts by weight, and even more preferably in an amount of 5 to
40 parts by weight relative to 100 parts by weight of the solid
content of the fine particles of a functional group-containing
cross-linkage type resin. If the addition amount of the compound
(D) is less than 0.1 parts by weight, the amount of functional
groups that contribute to an adhesion to a current collector
becomes less, and may not sufficiently contribute to the
improvement of adhesion to a current collector. Furthermore, if the
addition amount of the compound (D) is beyond 50 parts by weight,
it may lead to the leakage of an electrolytic solution of the
compound (D), or it may be a bad influence on the binder
performances. Furthermore, the compound (D) may be used in
combination of two kinds or more.
[0095] The molecular weight of the compound (D) is not particularly
limited, but the weight average molecular weight is preferably
1,000 to 1,000,000, and further more preferably 5,000 to 500,000.
If the weight-average molecular weight is less than 1,000, the
effects of adhesion to a current collector may not be sufficient.
Furthermore, if the weight average molecular weight is beyond
1,000,000, viscosity of the compound may increase, and the handling
property at the time of manufacturing an electrode may become
deteriorated. Furthermore, the weight average molecular weight is a
value relative to polystyrene standards measured by a
gel-permeation chromatography (GPC) method. Furthermore, the
compound (D) may be a compound that dissolves in a solvent, or a
compound that disperses in a solvent.
<Third Component in Composition of the Present Invention>
[0096] A third component may be added to the binder composition for
a non-aqueous secondary battery electrode of the present invention,
which is different from the fine particles of a functional
group-containing cross-linkage type resin and the compound (D), for
the purpose of adjusting flexibility or anti-electrolytic solution
property of the binder.
<Cross-Linking Agent>
[0097] As the third component, for example, a cross-linking agent
(compound (1)) that cross-links the fine particles of a functional
group-containing cross-linkage type resin and the compound (D), or
cross-links the compounds (D) to each other, may be added.
[0098] The cross-linking reaction in the present invention includes
those described below. Examples of the functional group that can
react with an epoxy group include a carboxyl group, an acid
anhydride group, a vinyl ether group, an amino group and the like.
Furthermore, examples of the functional group that can react with
an amide group include a carbonyl group and the like. Furthermore,
examples of the functional group that can react with a hydroxide
group include an isocyanate group and the like. Furthermore,
examples of the functional group that can react with a carboxyl
group include an epoxy group, an aziridinyl group, a carbodiimide
group, an oxazoline group and the like. Furthermore, examples of
the functional group that can react with a sulfonic acid group
include a hydroxide group, an epoxy group, an amino group and the
like. Furthermore, examples of the functional group that can react
with a phosphoric acid group include a hydroxide group, an epoxy
group, an amino group and the like.
[0099] The compound (1) (cross-linking agent) that may be used in
the present invention is exemplified as follows. Examples of the
compound having two or more carboxyl groups include, for example,
aromatic dicarboxylic acids such as o-phthalic acid, isophthalic
acid, terephthalic acid, 1,4-dimethylterephthalic acid,
1,3-dimethylisophthalic acid, 5-sulfo-1,3-dimethylisophthalic acid,
4,4-biphenyldicarboxylic acid, 1,4-naphthalene dicarboxylic acid,
2,6-naphthalene dicarboxylic acid, norbornene dicarboxylic acid,
diphenylmethane-4,4'-dicarboxylic acid and phenylindane
dicarboxylic acid; aromatic dicarboxylic acid anhydrides such as
phthalic acid anhydride, 1,8-naphthalenedicarboxylic acid anhydride
and 2,3-naphthalenedicarboxylic acid anhydride; alicyclic
dicarboxylic acids such as hexahydroterephthalic acid,
hexahydroisophthalic acid, hexahydrophthalic acid and
tetrahydrophthalic acid; alicyclic dicarboxylic acid anhydrides
such as hexahydrophthalic acid anhydride,
3-methyl-hexahydrophthalic acid anhydride,
4-methyl-hexahydrophthalic acid anhydride and
1,2-cyclohexanedicarboxylic acid anhydride; aliphatic dicarboxylic
acids such as oxalic acid, malonic acid, succinic acid, adipic
acid, sebacic acid, azelaic acid, suberic acid, maleic acid,
chloromaleic acid, fumaric acid, dodecanedioic acid, pimelic acid,
citraconic acid, glutaric acid, itaconic acid, and the like.
[0100] Examples of the compound having two or more acid anhydride
group include, for example, pyromellitic acid anhydride,
benzophenone tetracarboxylic acid dianhydride,
biphenyltetracarboxylic acid dianhydride, oxydiphthalic acid
dianhydride, diphenylsulfone tetracarboxylic acid dianhydride,
diphenylsulfide tetracarboxylic acid dianhydride, butane
tetracarboxylic acid dianhydride, perylene tetracarboxylic acid
dianhydride, naphthalenetetracarboxylic acid dianhydride, "RIKACID
TMTA-C", "RIKACID MTA-10", "RIKACID MTA-15", "RIKACID TMEG series"
and "RIKACID TDA" manufactured by New Japan Chemical co., ltd., and
the like.
[0101] Examples of the compound having two or more vinyl ether
group include, for example, ethylene glycol divinyl ether,
diethylene glycol divinyl ether, triethylene glycol divinyl ether,
tetraethylene glycol divinyl ether, pentaerythritol divinyl ether,
propylene glycol divinyl ether, dipropylene glycol divinyl ether,
tripropylene glycol divinyl ether, neopentyl glycol divinyl ether,
1,4-butanedioldivinyl ether, 1,6-hexanedioldivinyl ether, glycerin
divinyl ether, trimethylol propanedivinyl ether,
1,4-dihydroxylcyclohexanedivinyl ether,
1,4-dihydroxymethylcyclohexanedivinyl ether, hydroquinonedivinyl
ether, ethylene oxide-modified hydroquinonedivinyl ether, ethylene
oxide-modified resorcindivinyl ether, ethylene oxide-modified
bisphenol A divinyl ether, ethylene oxide-modified bisphenol S
divinyl ether, glycerin trivinyl ether, sorbitol tetravinyl ether,
trimethylol propane trivinyl ether, pentaerythritol trivinyl ether,
pentaerythritol tetravinyl ether, dipentaerythritol hexavinyl
ether, dipentaerythritol polyvinyl ether, ditrimethylol propane
tetravinyl ether, ditrimethylol propane polyvinyl ether, and the
like.
[0102] Examples of the compound having two or more amino groups
include, for example, aliphatic diamines such as ethylene diamine
and hexamethylenediamine; alicyclic diamines such as
4,4'-diamino-3,3'-dimethyldicyclohexylmethane,
4,4'-diamino-3,3'-dimethyldicyclohexyl, diaminocyclohexane and
isophoronediamine; aromatic aliphatic diamines such as xylylene
diamine and .alpha.,.alpha.,.alpha.',.alpha.'-tetramethylxylylene
diamine, and the like.
[0103] Examples of the compound having a carbonyl group include,
for example, aldehyde compounds such as formalin or
paraformaldehyde. When formalin is added, the amide group included
in the fine particles of a functional group-containing
cross-linkage type resin reacts with formalin, to produce a
methylol group. Thus-obtained methylol group may be used in the
formation of the cross-linking structure.
[0104] Examples of the compound having two or more isocyanate
groups include, for example, aromatic polyisocyanate, aliphatic
polyisocyanate, aromatic aliphatic polyisocyanate, alicyclic
polyisocyanate, and the like.
[0105] Examples of the aromatic polyisocyanate include, for
example, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate,
1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate,
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene,
1,3,5-triisocyanate benzene, dianisidine diisocyanate,
4,4'-diphenyl ether diisocyanate, 4,4',4''-triphenylmethane
triisocyanate, xylylene diisocyanate, and the like.
[0106] Examples of the aliphatic polyisocyanate include, for
example, trimethylene diisocyanate, tetramethylene diisocyanate,
hexamethylene diisocyanate (also known as HMDI), pentamethylene
diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene
diisocyanate, 1,3-butylene diisocyanate, dodecamethylene
diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the
like.
[0107] Examples of the aromatic aliphatic polyisocyanate include,
for example, .omega.,.omega.'-diisocyanate-1,3-dimethyl benzene,
.omega.,.omega.'-diisocyanate-1,4-dimethyl benzene,
.omega.,.omega.'-diisocyanate-1,4-diethyl benzene,
1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene
diisocyanate, and the like.
[0108] Examples of the alicyclic polyisocyanate include, for
example, 3-isocyanate methyl-3,5,5-trimethylcyclohexylisocyanate
(also known as IPDI, isophorone diisocyanate), 1,3-cyclopentane
diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane
diisocyanate, methyl-2,4-cyclohexane diisocyanate,
methyl-2,6-cyclohexane diisocyanate, 4,4'-methylene
bis(cyclohexylisocyanate), 1,4-bis(isocyanate methyl)cyclohexane,
and the like.
[0109] Furthermore, a trimethylol propane adduct of the
polyisocyanate mentioned above or a trimer having an isocyanurate
ring or the like may be also used. Furthermore, polyphenylmethane
polyisocyanate (also known as PAPI), naphthylene diisocyanate, and
polyisocyanate-modified substance thereof or the like may be used.
Furthermore, as the polyisocyanate-modified substance, a
modified-substance having any one kind, or two or more groups of a
carbodiimide group, a uretdione group, a uretimine group, the
burette group reacted with water, and an isocyanurate group may be
also used. Furthermore, a reaction product of polyol and
diisocyanate may be also used as the polyfunctional isocyanate
compound.
[0110] Examples of the compound having two or more epoxy groups
include the polyfunctional compounds among the non-cross-linked
epoxy group-containing compound described above as the compound
(D).
[0111] Examples of the compound having two or more aziridinyl
groups include, for example,
N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide),
N,N'-toluene-2,4-bis(1-aziridinecarboxamide),
bisisophthaloyl-1-(2-methylaziridine), tri-1-aziridinyl
phosphineoxide, N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide),
trimethylol propane-tri-.beta.-aziridinyl propionate, tetramethylol
methane-tri-.beta.-aziridinyl propionate,
tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, trimethylol propane
tris[3-(1-aziridinyl)propionate], trimethylol propane
tris[3-(1-aziridinyl)butyrate], trimethylol propane
tris[3-(1-(2-methyl)aziridinyl)propionate], trimethylol propane
tris[3-(1-aziridinyl)-2-methylpropionate],
2,2'-bishydroxymethylbutanol tris[3-(1-aziridinyl)propionate],
pentaerythritol tetra[3-(1-aziridinyl)propionate],
diphenylmethane-4,4-bis-N,N'-ethylene urea, 1,6-hexamethylene
bis-N,N'-ethylene urea, 2,4,6-(triethylene imino)-Syn-triazine,
bis[1-(2-ethyl)aziridinyl]benzene-1,3-carboxylic acid amide, and
the like.
[0112] Examples of the compound having two or more carbodiimide
groups include CARBODILITE series of Nisshinbo Holdings Inc. Among
them, CARBODILITE V-02,04,06, E-01,02 or 03A are preferable since
they are an aqueous type or an aqueous emulsion type, and thus have
good compatibility with the fine particles of a functional
group-containing cross-linkage type resin of the present invention.
Furthermore, it is also possible to use oil type CARBODILITE such
as CARBODILITE V-05 by being converted to an aqueous dispersion
using, for example, a surfactant in the binder composition of the
present invention.
[0113] Examples of the compound having two or more oxazoline groups
include the non-cross-linked oxazoline group-containing compounds
described above as the compound (D).
[0114] Examples of the compounds having two or more hydroxide
groups include the polyfunctional compounds among the
non-cross-linked hydroxide group-containing compounds described
above as the compound (D).
[0115] The compound (1) used as such a cross-linking agent is added
preferably in 0.1 to 50 parts by weight, and even more preferably
in 1 to 40 parts by weight relative to 100 parts by weight of the
solid content of the fine particles of a functional
group-containing cross-linkage type resin. The cross-linking agent
to be added can be used in an amount that it may not lead to a bad
influence on the binder performance such as the leakage of an
electrolytic solution of the cross-linking agent components, or the
occurrence of a variation in manufacturing electrodes.
[0116] Furthermore, the compound (1) in the binder composition may
be used in combination of two kinds or more. For example, a monomer
(a)-derived epoxy group reacts with a carboxyl group, whereby to
produce a hydroxide group. This hydroxide group may be further
reacted with a compound having two or more isocyanate groups,
whereby to form a strong cross-linking structure.
[0117] The cross-linking reaction of at least one functional group
that is selected from an epoxy group, an amide group, and a
hydroxide group in the fine particles of a functional
group-containing cross-linkage type resin, and the functional group
in the compound (1), may be carried out with heating treatment if
necessary at the time of manufacturing an electrode for the purpose
of strengthening the cross-linkage and adjusting the binder
performances. For example, the reaction of a carboxyl group in the
fine particles of a functional group-containing cross-linkage type
resin, with epoxy groups in a compound having two or more epoxy
groups is preferably conducted with heating treatment at
160.degree. C. to 250.degree. C.
[0118] Furthermore, a third component may be added to the binder
composition, in addition to the compound (1), for the purpose of
further strengthening the cross-linking structure of the binder
composition, or for the purpose of improving an adhesion to a
current collector, and further for the purpose of adjusting the
mechanical strength of the binder. As an additive for the purpose
of improving adhesion to a current collector, a component of
generally improving the adhesion to a metal, for example,
phosphoric acid, imidazole silane-based compound or the like may be
added since a current collector is mainly a metal compound.
Furthermore, as an additive of adjusting mechanical strength of the
binder, a resin such as a polyamide resin, a polyester resin and a
polyurethane resin may be blended. Such a third component is not
limited thereto as long as they satisfy the purposes described
above.
<Third Component Such as Auxiliary Agent for Formation of
Film>
[0119] An auxiliary agent for the formation of a film, an
antifoaming agent, a leveling agent, an antiseptic agent, a
pH-adjusting agent, a viscosity-adjusting agent or the like may be
incorporated if necessary into the binder composition for a
non-aqueous secondary battery electrode containing the fine
particles of a functional group-containing cross-linkage type resin
of the present invention.
[0120] The auxiliary agent for formation of a film helps the
formation of a coating film and has a function of temporary
plasticization by being relatively rapidly evaporated and
volatilized after the formation of the coating film whereby to
improve the strength of the coating film. A solvent having a
boiling point of 110.degree. C. to 200.degree. C. is suitably used.
Specifically, examples of the solvent include propylene glycol
monobutyl ether, ethylene glycol methyl ether, ethylene glycol
ethyl ether, ethylene glycol monobutyl ether, diethylene glycol
diethyl ether, dipropylene glycol monopropyl ether, carbitol,
butylcarbitol, dibutylcarbitol, benzyl alcohol, and the like. Among
them, ethylene glycol monobutyl ether or propylene glycol monobutyl
ether is particularly preferable since they have high effects as an
auxiliary agent for the formation of a film even in a small amount.
Such an auxiliary agent for the formation of a film is preferably
included in 0.5 to 151 by weight in the binder composition.
[0121] The viscosity-adjusting agent may be used in 1 to 100 parts
by weight relative to 100 parts by weight of the fine particles of
a functional group-containing cross-linkage type resin. Examples of
the viscosity-adjusting agent include, for example, carboxymethyl
cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl
cellulose, polyvinyl alcohol, polyacrylic acid (and a salt
thereof), starch oxide, starch phosphate, casein and the like.
<Use Form of the Binder Composition of the Present
Invention>
[0122] The binder composition for a non-aqueous secondary battery
electrode of the present invention may be used for a positive
electrode and a negative electrode of a secondary battery. In
addition to them, the binder composition of the present invention
may also be used for an energy device, i.e. a capacitor, a lithium
ion capacitor, a solar battery, and the like.
[0123] The binder composition for a non-aqueous secondary battery
electrode of the present invention is obtained by blending the fine
particles of a functional group-containing cross-linkage type resin
with an electrode-active material, and, if necessary, the compound
(D) and the compound (1), and further if necessary, additives such
as a conductive material, and a non-aqueous secondary battery
electrode may be produced by coating such a binder composition for
a non-aqueous secondary battery electrode on a current collector,
and drying it.
[0124] In the present invention, the fine particles of a functional
group-containing cross-linkage type resin are used usually in 0.1
to 20 parts by weight, and preferably in 0.5 to 10 parts by weight
relative to 100 parts by weight of an electrode-active material. If
the amount of the fine particles of a functional group-containing
cross-linkage type resin is less than 0.1 parts by weight, the
adhesion force of the electrode-active material to a current
collector may be insufficient, and the electrode-active material
may drop off, leading to the lowering of the battery capacity. On
the other hand, if the amount of the fine particles of a functional
group-containing cross-linkage type resin is beyond 20 parts by
weight, the resistance in the battery may increase, leading to the
lowering of the battery capacity.
[0125] Examples of the electrode-active material include, for
example, carbonaceous materials such as carbon fluoride, graphite,
natural black lead and carbon fiber, conductive polymers such as
polyacene, lithium-based metals such as a lithium metal and a
lithium alloy, or the like as an active material for a negative
electrode. Furthermore, examples of the electrode-active material
include oxides, sulfides, and selenides of manganese, molybdenum,
vanadium, titanium and niobium, and the like as an active material
for a positive electrode. Furthermore, in combination with the
electrode-active material, a conductive material may also be
used.
[0126] Examples of the conductive material used in combination with
the electrode-active material include, for example, nickel powders,
cobalt oxide, titanium oxide, carbon and the like. Examples of the
carbon include acetylene black, furnace black, black lead, carbon
fiber and fullerenes. The amount of the conductive material used is
preferably 0.5 to 10 parts by weight relative to 100 parts by
weight of the electrode-active material. If the amount of the
conductive material is less than 0.5 parts by weight, the
conductivity may be lowered, and the capacity when the secondary
battery charges and discharges at a high rate, may be lowered. The
current collector is not particularly limited as long as it is
usually used for a secondary battery electrode, and examples of the
current collector include, for example, a punching metal, an
expanded metal, a metallic mesh, a foamed metal, a reticular metal
fiber, a sintered body and the like.
[0127] In forming the non-aqueous secondary battery electrode, the
binder composition for a non-aqueous secondary battery electrode is
coated on a current collector as a slurry form, heated and dried.
As a method of coating the composition for a secondary battery
electrode, any coater head may be used such as a reverse roll
method, a commabar method, a Gravure method, an air knife method
and the like. As a dry method, standing dry, a blowing dryer, a hot
air dryer, an infrared heater, a far infrared heater or the like
may be used.
[0128] The non-aqueous secondary battery of the present invention
has electrodes for a secondary battery manufactured by using the
binder composition for a non-aqueous secondary battery electrode.
When the non-aqueous secondary battery is manufactured using the
electrodes for a non-aqueous secondary battery obtained as
described above, the non-aqueous secondary battery is preferably
used as a lithium ion secondary battery by using, for example, a
carbonate-based solvent such as ethylene carbonate and propylene
carbonate as the electrolytic solution, and a lithium ion compound
such as LiPF.sub.6 as the electrolyte. Furthermore, the battery is
composed of components such as a separator, a current collector,
terminals and an insulating plate. Examples of the separator
include, for example, a polyethylene non-woven fabric, a
polypropylene non-woven fabric, a polyamide non-woven fabric and
those obtained by subjecting them to a hydrophilic treatment.
EXAMPLES
[0129] The present invention will be further specifically explained
below with Examples. However, Examples below do not limit the
protection scope of the present invention. Furthermore, the "part"
in Examples represents "part by weight" and "%" represents "% by
weight".
<Preparation of Aqueous Dispersion of Fine Particles of
Resin>
Example 1
[0130] To a reaction vessel equipped with a stirrer, a thermometer,
a dropping funnel, and a reflux device, 40 parts of ion-exchange
water and 0.2 part of ADEKA REASOAP SR-10 (manufactured by ADEKA
CORPORATION) as a surfactant were introduced, and separately, 1%
pre-emulsion, which was obtained by previous mixing of 50 parts of
styrene, 45 parts of 2-ethylhexyl acrylate, 1.5 parts of methyl
methacrylate, 1 part of acrylic acid, 2 parts of diacetone acrylic
amide, 0.5 part of 3-methacryloxypropyltrimethoxysilane, 53 parts
of ion-exchange water and 1.8 parts of ADEKA REASOAP SR-10
(manufactured by ADEKA CORPORATION) as a surfactant, was further
added thereto. The reaction vessel was heated to an internal
temperature of 70.degree. C. and sufficiently purged with nitrogen,
and then 10% of 10 parts of an aqueous solution of 5% potassium
persulfate were added to initiate polymerization. The inside
temperature of the reaction system was retained at 70.degree. C.
for 5 minutes, and then the residual pre-emulsion and the residual
aqueous solution of 5% potassium persulfate were dropped over 3
hours while the internal temperature was maintained at 70.degree.
C., and stirring was continued for further 2 hours. After
confirmation of more than 98% of the conversion ratio from
measurement of the solid content, the mixture was cooled to a
temperature of 30.degree. C. 25% ammonia water was added thereto,
and the pH was adjusted to 8.5, and further the solid content was
adjusted to 48% with ion-exchange water, whereby to obtain an
aqueous dispersion of fine particles of the resin. Furthermore, the
solid content was determined from a residue after baking at
150.degree. C. for 20 minutes.
Examples 2 to 21 and Comparative Examples 1 to 5
[0131] Aqueous dispersion bodies of fine particles of the resin of
Example 2 to 21, and Comparative Example 1 to 5 were obtained in
the blending compositions shown in Tables 1 and 2 by a synthesis
method similar to that of Example 1. However, the resin was
aggregated at the time of the emulsification polymerization in
Comparative Examples 2 and 4, and the intended fine particles of
the resin could not be obtained.
TABLE-US-00001 TABLE 1 EXAMPLE NUMBER 1 2 3 4 5 6 monomer monomer
glycidyl methacrylate 4 10 10 (A) (a) monomer acrylamide 2.5 (b)
diacetone acrylamide 2 N-methylol acrylamide 0.5 monomer 2-hydroxy
ethyl 15 5 3 (c) methacrylate monomer monomer 3-methacryloxy propyl
0.5 0.2 1 1.5 (B) (d) trimethoxy silane vinyl triethoxy 1 0.2
silane monomer allyl methacrylate 1.5 (e) monomer monomer 2-ethyl
hexyl 45 30 30 10 (C) (m) acrylate lauryl methacrylate 20 monomer
styrene 50 30 35 (n) cyclohexyl 50 50 methacrylate phenoxy ethyl 30
20 3 10 acrylate others acrylic acid 1 0.2 1 8 methacrylic acid
t-butyl methacrylate 5 styrene sulfonicacid 1 (2-hydroxy ethyl) 1
methacrylate acid phosphate acetoacetoxy ethyl methacrylate methyl
methacrylate 1.5 50 14.8 butyl acrylate 9.8 3 9 8.8 acrylonitrile 5
10 surfactant: ADEKA REASOAP SR-10 2 2 2 2 2 2 surfactant: ADEKA
REASOAP ER-20 ionexchange water(pre-emulsion) 53 53 53 53 53 53
polymerization initiator: 5% potassium 10 10 24 30 10 12 persulfate
aqueous solution ionexchange water(in reaction vessel) 40 41 27 21
41 39 EXAMPLE NUMBER 7 8 9 10 11 12 monomer monomer glycidyl
methacrylate 16 0.2 1 (A) (a) monomer acrylamide 0.2 6 10 (b)
diacetone acrylamide N-methylol acrylamide 1 monomer 2-hydroxy
ethyl 0.3 1 (c) methacrylate monomer monomer 3-methacryloxy propyl
0.5 0.5 0.5 (B) (d) trimethoxy silane vinyl triethoxy silane
monomer allyl methacrylate 0.5 5 3 (e) monomer monomer 2-ethyl
hexyl 3 10 47 (C) (m) acrylate lauryl methacrylate monomer styrene
40 (n) cyclohexyl 50 methacrylate phenoxy ethyl 30 acrylate others
acrylic acid 1 1 methacrylic acid t-butyl methacrylate 10 5 styrene
sulfonicacid 1 (2-hydroxy ethyl) 5 1 methacrylate acid phosphate
acetoacetoxy ethyl methacrylate methyl methacrylate 10 31.5 33.3
57.5 butyl acrylate 45.3 18 60 50 30 acrylonitrile 5 10 surfactant:
ADEKA REASOAP SR-10 1 2 2 3 1 surfactant: ADEKA REASOAP ER-20 1 3 5
ionexchange water(pre-emulsion) 53 53 53 53 53 53 polymerization
initiator: 5% potassium 16 10 10 10 10 10 persulfate aqueous
solution ionexchange water(in reaction vessel) 35 41 40 40 40 40
EXAMPLE NUMBER 13 14 15 16 17 monomer monomer glycidyl methacrylate
(A) (a) monomer acrylamide 2 1 0.1 1.9 2 (b) diacetone acrylamide
0.2 9 N-methylol acrylamide monomer 2-hydroxy ethyl (c)
methacrylate monomer monomer 3-methacryloxy propyl 0.5 0.1 (B) (d)
trimethoxy silane vinyl triethoxy 1 0.2 silane monomer allyl
methacrylate 0.3 2 (e) monomer monomer 2-ethyl hexyl 24.5 45 45 (C)
(m) acrylate lauryl methacrylate monomer styrene 40 50 40 11 30 (n)
cyclohexyl methacrylate phenoxy ethyl 20 acrylate others acrylic
acid 1 0.1 methacrylic acid 3 2 t-butyl methacrylate styrene
sulfonicacid 3 (2-hydroxy ethyl) methacrylate acid phosphate
acetoacetoxy 5 ethyl methacrylate methyl methacrylate 10 1.8 5.5 40
30 butyl acrylate 20 40 7.8 acrylonitrile 5 surfactant: ADEKA
REASOAP SR-10 2 2 2 2 2 surfactant: ADEKA REASOAP ER-20 ionexchange
water(pre-emulsion) 53 53 53 53 53 polymerization initiator: 5%
potassium 10 10 10 10 30 persulfate aqueous solution ionexchange
water(in reaction vessel) 40 40 40 40 21 EXAMPLE NUMBER 18 19 20 21
monomer monomer glycidyl methacrylate 5 (A) (a) monomer acrylamide
2 2 (b) diacetone acrylamide N-methylol acrylamide monomer
2-hydroxy ethyl 10 (c) methacrylate monomer monomer 3-methacryloxy
propyl 0.5 0.5 (B) (d) trimethoxy silane vinyl triethoxy 2 4 silane
monomer allyl methacrylate (e) monomer monomer 2-ethyl hexyl 30 10
45 40 (C) (m) acrylate lauryl methacrylate 17 monomer styrene 40 50
40 (n) cyclohexyl 40 methacrylate phenoxy ethyl 3 10 acrylate
others acrylic acid 1 15 methacrylic acid t-butyl methacrylate 2
styrene sulfonicacid (2-hydroxy ethyl) 8 methacrylate acid
phosphate acetoacetoxy ethyl methacrylate methyl methacrylate 2.5
2.5 butyl acrylate 8 acrylonitrile 10 surfactant: ADEKA REASOAP
SR-10 2 2 2 2 surfactant: ADEKA REASOAP ER-20 ionexchange
water(pre-emulsion) 53 53 53 53 polymerization initiator: 5%
potassium 10 12 10 10 persulfate aqueous solution ionexchange
water(in reaction vessel) 41 39 40 40
TABLE-US-00002 TABLE 2 COMPARATIVE EXAMPLE NUMBER 1 2 3 4 5 monomer
monomer glycidyl methacrylate 30 (A) (a) monomer acrylamide 5 (b)
diacetone acrylamide N-methylol acrylamide monomer 2-hydroxy ethyl
2 (c) methacrylate monomer monomer 3-methacryloxy propyl 0.5 0.5
(B) (d) trimethoxy silane vinyl triethoxy silane monomer allyl
methacrylate 10 (e) monomer monomer 2-ethyl hexyl 45 30 42 40 45
(C) (m) acrylate lauryl methacrylate monomer styrene 50 35 50 45 50
(n) cyclohexyl methacrylate phenoxy ethyl acrylate others acrylic
acid 1 1 1 1 methacrylic acid t-butyl methacrylate styrene
sulfonicacid (2-hydroxy ethyl) methacrylate acid phosphate
acetoacetoxy ethyl methacrylate methyl methacrylate 3.5 3.5 2 2 5
butyl acrylate acrylonitrile surfactant: ADEKA REASOAP SR-10 2 2 2
2 2 surfactant: ADEKA REASOAP ER-20 ionexchange water(pre-emulsion)
53 53 53 53 53 polymerization initiator: 5% potassium 10 10 10 10
10 persulfate aqueous solution ionexchange water(in reaction
vessel) 40 40 40 40 40
[0132] Furthermore, the product names in Tables 1 and 2 will be
explained below.
[0133] ADEKAREASOAP SR-10; Alkyl ether-based anionic surfactant
(manufactured by ADEKA CORPORATION)
[0134] ADEKA REASOAP ER-20; Alkyl ether-based nonionic surfactant
(manufactured by ADEKA CORPORATION)
<Preparation of Butyl Acrylate/Acrylic Acid Copolymer
Solution>
Comparative Example 6
[0135] To a reaction vessel equipped with a stirrer, a thermometer,
a dropping funnel, and a reflux device, 40 parts of isopropyl
alcohol was introduced, and separately, 80 parts of butyl acrylate
and 20 parts acrylic acid were introduced to a dropping bath 1, and
2 parts of azobisisobutyronitrile dissolved in 60 parts of
isopropyl alcohol was introduced to a dropping bath 2. The reaction
vessel was heated to an internal temperature of 70.degree. C. and
sufficiently purged with nitrogen, and then dropped with the
mixtures in the dropping baths 1 and 2 over 2 hours to conduct
polymerization. After the completion of the dropping, stirring was
continued while the internal temperature was maintained at
70.degree. C. for an hour. After the confirmation of more than 98%
of the conversion ratio from measurement of the solid content, the
mixture was cooled to a temperature of 30.degree. C., to obtain a
butyl acrylate/acrylic acid copolymer solution having a 50% solid
content. Furthermore, the solid content was determined from a
residue after baking at 150.degree. C. for 20 minutes.
<Preparation of Methyl Methacrylate/Glycidyl Methacrylate
Copolymer Solution>
Comparative Example 7
[0136] A methyl methacrylate/glycidyl methacrylate copolymer
solution having a 50% solid content was obtained by a method
similar to that of Comparative Example 6 using 88 parts of methyl
methacrylate and 12 parts of glycidyl methacrylate.
<Production of Compound (D) [Production of Epoxy
Group-Containing Compound]>
Preparation Example 1
[0137] To a reaction vessel equipped with a stirrer, a thermometer,
a dropping funnel, and a reflux device, 20 parts of isopropyl
alcohol and 20 parts of water were introduced, and separately, 40
parts of methyl methacrylate, 40 parts of methyl acrylate and 20
parts of glycidyl methacrylate were introduced into to the dropping
bath 1, and 2 parts of potassium persulfate dissolved in 30 parts
of isopropyl alcohol and 30 parts of water were introduced into the
dropping bath 2. The reaction vessel was heated to an internal
temperature of 80.degree. C. and sufficiently purged with nitrogen,
and then dropped with the mixtures in the dropping baths 1 and 2
over 2 hours to conduct polymerization. After the completion of the
dropping, stirring was continued while the internal temperature was
maintained at 80.degree. C. for an hour. After the confirmation of
more than 98% of the conversion ratio from measurement of the solid
content, the mixture was cooled to a temperature of 30.degree. C.,
and a solution of an epoxy group-containing compound (methyl
methacrylate/methyl acrylate/glycidyl methacrylate copolymer)
having a 50% solid content was obtained. Furthermore, the solid
content was determined from a residue after baking at 150.degree.
C. for 20 minutes.
<Production of Compound (D) [Production of Amide
Group-Containing Compound]>
Preparation Example 2
[0138] To a reaction vessel equipped with a stirrer, a thermometer,
a dropping funnel, and a reflux device, 90 parts of water was
introduced, and separately, 20 parts of acrylic amide was
introduced to the dropping bath 1, and 2 parts of potassium
persulfate dissolved in 90 parts of water was introduced into the
dropping bath 2. The reaction vessel was heated to an internal
temperature of 80.degree. C. and sufficiently purged with nitrogen,
and then dropped with the mixtures in the dropping baths 1 and 2
over 2 hours to conduct polymerization. After the completion of the
dropping, stirring was continued while the internal temperature was
maintained at 80.degree. C. for an hour. After the confirmation of
more than 98% of the conversion ratio from measurement of the solid
content, the mixture was cooled to a temperature of 30.degree. C.,
to obtain a solution of an amide group-containing compound
(polyacrylic amide) having a 10% solid content. Furthermore, the
solid content was determined from a residue after baking at
150.degree. C. for 20 minutes.
Preparation Example 3
[0139] To a reaction vessel equipped with a stirrer, a thermometer,
a dropping funnel, and a reflux device, 40 parts of water were
introduced, and separately, 40 parts of 2-ethylhexyl acrylate, 40
parts of styrene and 20 parts of dimethyl acrylic amide were
introduced to the dropping bath 1, and 2 parts of potassium
persulfate dissolved in 60 parts of water were introduced to the
dropping bath 2. The reaction vessel was heated to an internal
temperature of 80.degree. C. and sufficiently purged with nitrogen,
and then dropped with the mixtures in the dropping baths 1 and 2
over 2 hours to conduct polymerization. After the completion of the
dropping, stirring was continued while the internal temperature was
maintained at 80.degree. C. for an hour. After the confirmation of
more than 98% of the conversion ratio from measurement of the solid
content, the mixture was cooled to a temperature of 30.degree. C.,
to obtain a solution of an amide group-containing compound
(2-ethylhexyl acrylate/styrene/dimethyl acrylic amide copolymer)
having a 50% solid content. Furthermore, the solid content was
determined from a residue after baking at 150.degree. C. for 20
minutes.
<Production of Compound (D) [Production of Hydroxide
Group-Containing Compound]>
Preparation Example 4
[0140] To a reaction vessel equipped with a stirrer, a thermometer,
a dropping funnel, and a reflux device, 20 parts of isopropyl
alcohol, and 20 parts of water were introduced, and separately, 40
parts of methyl methacrylate, 40 parts of butyl acrylate and 20
parts 2-hydroxyethyl methacrylate were introduced to the dropping
bath 1, and 2 parts of potassium persulfate and 30 parts of
isopropyl alcohol dissolved in 30 parts of water were introduced to
the dropping bath 2. The reaction vessel was heated to an internal
temperature of 80.degree. C. and sufficiently purged with nitrogen,
and then dropped with the mixtures in the dropping baths 1 and 2
over 2 hours to conduct polymerization. After the completion of the
dropping, stirring was continued while the internal temperature was
maintained at 80.degree. C. for 1 hour. After the confirmation of
more than 98% of the conversion ratio from measurement of the solid
content, the mixture was cooled to a temperature of 30.degree. C.,
to obtain a solution of a hydroxide group-containing compound
(methyl methacrylate/butyl acrylate/2-hydroxyethyl methacrylate
copolymer) having a 50% solid content. Furthermore, the solid
content was determined from a residue after baking at 150.degree.
C. for 20 minutes.
<Manufacture of the Binder Composition for a Positive
Non-Aqueous Secondary Battery Electrode and a Negative Non-Aqueous
Secondary Battery Electrode>
Examples 22 to 42 and Comparative Examples 8 to 10
[0141] (Manufacture of Positive Electrode)
[0142] To 100 parts of the solid content of an aqueous dispersion
of fine particles of the resin obtained in Examples 1 to 21 and
Comparative Examples 1, 3 and 5, 4700 parts of lithium cobaltate
(LiCoO.sub.2) as a positive electrode-active material, 100 parts of
acetylene black and 100 parts of carboxymethyl cellulose as a
thickening agent were added respectively, and ion-exchange water
was added to a 50% solid content, and then the mixture was kneaded,
whereby to prepare the binder composition for a non-aqueous
secondary battery electrode.
[0143] Furthermore, such a binder composition for a non-aqueous
secondary battery electrode was coated respectively using a doctor
blade on an aluminum foil having 20 .mu.m thickness which served as
a current collector, and then dried by heating under reduced
pressure, and subjected to a milling treatment by a roll press,
whereby to manufacture a positive electrode having a positive
electrode mixture layer having 50 .mu.m thickness.
[0144] The binder composition for a positive electrode and the
positive electrode obtained by such procedures using the aqueous
dispersion of fine particles of the resin in Examples 1 to 21 and
Comparative Examples 1, 3 and 5 were designated respectively as a
binder composition for a positive electrode and a positive
electrode related to Examples 22 to 42 and Comparative Examples 8
to 10.
[0145] (Manufacture of Negative Electrode)
[0146] To 100 parts of the solid content of an aqueous dispersion
of fine particles of the resin obtained in Examples 1 to 21 and
Comparative Examples 1, 3 and 5, 4800 parts of mesophase carbon
(MCMB 6-28, 5 to 7 .mu.m average particle diameter, 4 m.sup.2/g
specific surface area manufactured by Osaka Gas Chemicals Co.,
Ltd.) as an active material for a negative electrode and 100 parts
of acetylene black were added respectively, and ion-exchange water
was added to a 50% solid content, and then the mixture was kneaded,
whereby to prepare the binder composition for a non-aqueous
secondary battery electrode.
[0147] Furthermore, such a binder composition for a non-aqueous
secondary battery electrode was coated respectively using a doctor
blade on an aluminum foil having 20 .mu.m thickness which served as
a current collector, and then dried by heating under reduced
pressure, and subjected to a milling treatment by a roll press,
whereby to manufacture a negative electrode having a negative
electrode mixture layer having 50 .mu.m thickness.
[0148] The binder composition for a negative electrode and the
negative electrode obtained by such procedures using the aqueous
dispersion of fine particles of the resin in Examples 1 to 21 and
Comparative Examples 1, 3 and 5 were designated respectively as a
binder composition for a negative electrode and a negative
electrode related to Examples 22 to 42 and Comparative Examples 8
to 10.
Examples 43 to 65
[0149] (Manufacture of Positive Electrode)
[0150] To 100 parts of the solid content of an aqueous dispersion
of fine particles of the resin obtained according to the
compositions shown in Table 3, 4700 parts of lithium cobaltate
(LiCoO.sub.2) as a positive electrode-active material, 100 parts of
acetylene black and 100 parts of carboxymethyl cellulose as a
thickening agent were added respectively, and ion-exchange water
was added to a 50% solid content, and then the mixture was kneaded,
whereby to prepare the binder composition for a non-aqueous
secondary battery electrode.
[0151] Furthermore, such a binder composition for a non-aqueous
secondary battery electrode was coated respectively using a doctor
blade on an aluminum foil having 20 .mu.m thickness which served as
a current collector, and then dried by heating under reduced
pressure, and subjected to a milling treatment by a roll press,
whereby to manufacture a positive electrode having a positive
electrode mixture layer having 50 .mu.m thickness.
[0152] The binder composition for a positive electrode and the
positive electrode obtained by such procedures using the aqueous
dispersion of fine particles of the resin obtained according to the
compositions shown in Table 3, were designated respectively as a
binder composition for a positive electrode and a positive
electrode related to Examples 43 to 65.
[0153] (Manufacture of Negative Electrode)
[0154] To 100 parts of the solid content of an aqueous dispersion
of fine particles of the resin obtained according to the
compositions shown in Table 3, 4800 parts of mesophase carbon (MCMB
6-28, 5 to 7 .mu.m average particle diameter, 4 m.sup.2/g specific
surface area manufactured by Osaka Gas Chemicals Co., Ltd.) as an
active material for a negative electrode and 100 parts of acetylene
black were added respectively, and ion-exchange water was added to
a 50% solid content, and then the mixture was kneaded, whereby to
prepare the binder composition for a non-aqueous secondary battery
electrode.
[0155] Furthermore, such a binder composition for a non-aqueous
secondary battery electrode was coated respectively using a doctor
blade on an aluminum foil having 20 .mu.m thickness which served as
a current collector, and then dried by heating under reduced
pressure, and subjected to a milling treatment by a roll press,
whereby to manufacture a negative electrode having a negative
electrode mixture layer having 50 .mu.m thickness.
[0156] The binder composition for a negative electrode and the
negative electrode obtained by such procedures using the aqueous
dispersion of fine particles of the resin obtained according to the
compositions shown in Table 3, were designated respectively as a
binder composition for a negative electrode and a negative
electrode related to Examples 43 to 65.
TABLE-US-00003 TABLE 3 EXAMPLE NUMBER 43 44 45 46 47 aqueous
dispersion of fine example number 13 3 4 6 14 particle resin parts
by weight 100 100 100 100 100 compound noncrosslinked epoxy resin
30.0 2.0 (D) epoxy group compound from containing preparation
Example compound 1 noncrosslinked compound from 10.0 amide group
preparation Example containing 2 compound compound from preparation
Example 3 noncrosslinked compound from 6.0 hydroxide group
preparation Example containing 4 compound 1,4-bis 15.0 (hydroxy
methyl) cyclohexane noncrosslinked oxazoline oxazoline group
containing acryl containing styrene resin compound 2'-p-phenylene
15.0 bis(2-oxazoline) other polyfunctional adipic acid compounds
hydrazide dihydrazide compound sebacic acid dihydrazide Ajicure VDH
carbodiimide CARBODILITE compound V-02 polyamide resin D1500A
aromatic 1,3-phenylene polyisocyanate diisocyanate aliphatic
hexamethylene diamine diamine EXAMPLE NUMBER 48 49 50 51 52 aqueous
dispersion of fine example number 2 1 6 6 5 particle resin parts by
weight 100 100 100 100 100 compound noncrosslinked epoxy resin 20.0
(D) epoxy group compound from 25.0 containing preparation Example
compound 1 noncrosslinked compound from amide group preparation
Example containing 2 compound compound from 5.0 24.0 preparation
Example 3 noncrosslinked compound from 30.0 1.0 hydroxide group
preparation Example containing 4 compound 1,4-bis 1.0 (hydroxy
methyl) cyclohexane noncrosslinked oxazoline 1.0 oxazoline group
containing acryl containing styrene resin compound 2'-p-phenylene
bis(2-oxazoline) other polyfunctional adipic acid compounds
hydrazide dihydrazide compound sebacic acid dihydrazide Ajicure VDH
carbodiimide CARBODILITE compound V-02 polyamide resin D1500A
aromatic 1,3-phenylene polyisocyanate diisocyanate aliphatic
hexamethylene diamine diamine EXAMPLE NUMBER 53 54 55 56 aqueous
dispersion of fine example number 13 13 8 6 particle resin parts by
weight 100 100 100 100 compound noncrosslinked epoxy resin (D)
epoxy group compound from 0.5 containing preparation Example
compound 1 noncrosslinked compound from 2.0 amide group preparation
Example containing 2 compound compound from preparation Example 3
noncrosslinked compound from 3.0 hydroxide group preparation
Example containing 4 compound 1,4-bis (hydroxy methyl) cyclohexane
noncrosslinked oxazoline 40.0 20.0 oxazoline group containing acryl
containing styrene resin compound 2'-p-phenylene 5.0
bis(2-oxazoline) other polyfunctional adipic acid compounds
hydrazide dihydrazide compound sebacic acid dihydrazide Ajicure VDH
carbodiimide CARBODILITE compound V-02 polyamide resin D1500A
aromatic 1,3-phenylene polyisocyanate diisocyanate aliphatic
hexamethylene diamine diamine EXAMPLE NUMBER 57 58 59 60 51 aqueous
dispersion of fine example number 1 14 15 16 17 particle resin
parts by weight 100 100 100 100 100 compound noncrosslinked epoxy
resin 5.0 (D) epoxy group compound from containing preparation
Example compound 1 noncrosslinked compound from amide group
preparation Example containing 2 compound compound from preparation
Example 3 noncrosslinked compound from hydroxide group preparation
Example containing 4 compound 1,4-bis (hydroxy methyl) cyclohexane
noncrosslinked oxazoline oxazoline group containing acryl
containing styrene resin compound 2'-p-phenylene bis(2-oxazoline)
other polyfunctional adipic acid 0.5 0.04 compounds hydrazide
dihydrazide compound sebacic acid 2 dihydrazide Ajicure VDH 1.5
carbodiimide CARBODILITE compound V-02 polyamide resin D1500A
aromatic 1,3-phenylene polyisocyanate diisocyanate aliphatic
hexamethylene diamine diamine EXAMPLE NUMBER 62 63 64 65 aqueous
dispersion of fine example number 18 19 3 6 particle resin parts by
weight 100 100 100 100 compound noncrosslinked epoxy resin (D)
epoxy group compound from containing preparation Example compound 1
noncrosslinked compound from amide group preparation Example
containing 2 compound compound from preparation Example 3
noncrosslinked compound from hydroxide group preparation Example
containing 4 compound 1,4-bis (hydroxy methyl) cyclohexane
noncrosslinked oxazoline oxazoline group containing acryl
containing styrene resin compound 2'-p-phenylene bis (2-oxazoline)
other polyfunctional adipic acid compounds hydrazide dihydrazide
compound sebacic acid dihydrazide Ajicure VDH carbodiimide
CARBODILITE 2.0 compound V-02 polyamide resin D1500A 20.0 aromatic
1,3-phenylene 30.0 polyisocyanate diisocyanate aliphatic
hexamethylene 15.0 diamine diamine
[0157] Furthermore, product names in Table 3 will be explained
below.
[0158] Epoxy resin; (product name: ADEKA resin EM-1-60L,
manufactured by ADEKA CORPORATION, 320 epoxy equivalents, bisphenol
A-epichlorohydrin type epoxy resin)
1,4-Bis(hydroxymethyl)cyclohexane; (manufactured by Wako Pure
Chemical Industries, Ltd.)
[0159] Oxazoline group-containing acrylate/styrene resin; (product
name: EPOCROS K-2020E, manufactured by NIPPON SHOKUBAI CO., LTD.,
550 oxazoline equivalents)
[0160] Ajicure VDH; (manufactured by Ajinomoto Fine-Techno Co.,
Inc.)
[0161] CARBODILITE V-02; carbodiimide curing agent (manufactured by
Nisshinbo Holdings Inc., 600 NCN equivalents)
[0162] Polyamide resin; co-polymerized polyamide resin (product
name: Griltex D1500A Suspension, manufactured by ESM-CHEMIE (Japan)
Ltd.)
Comparative Examples 11, 12 and 13
[0163] (Manufacture of Positive Electrode)
[0164] To 100 parts of the aqueous dispersion of fine particles of
the resin obtained in Comparative Example 5, or the solid content
of the copolymer solution obtained in Comparative Examples 6 and 7,
4700 parts of lithium cobaltate (LiCoO.sub.2) as a positive
electrode-active material, 100 parts of acetylene black and 100
parts of carboxymethyl cellulose as a thickening agent
(furthermore, 30 parts of a tri-functional epoxy resin [product
name: Denacol EX321, manufactured by Nagase ChemteX Corporation]
for the aqueous dispersion of fine particles of the resin obtained
in Comparative Example 5, 50 parts of a tri-functional epoxy resin
[Denacol EX321] for the copolymer solution obtained in Comparative
Example 6, and 50 parts of diaminodiphenyl ether [DPE/ODA,
manufactured by SEIKA CORPORATION] for the copolymer solution
obtained in Comparative Example 7), which were dissolved in
toluene, were added respectively, and the mixture was adjusted to
have a 50% solid content in a final binder composition, and
kneaded, whereby to prepare the binder composition for a
non-aqueous secondary battery electrode.
[0165] Furthermore, such a binder composition for a non-aqueous
secondary battery electrode was coated respectively using a doctor
blade on an aluminum foil having 20 .mu.m thickness which served as
a current collector, and then dried by heating under reduced
pressure, and subjected to a milling treatment by a roll press,
whereby to manufacture a positive electrode having a positive
electrode mixture layer having 50 .mu.m thickness.
[0166] The binder composition for a positive electrode and the
positive electrode obtained by such procedures using the aqueous
dispersion of fine particles of the resin obtained in Comparative
Example 5, the copolymer solutions obtained in Comparative Examples
6 and 7 were designated respectively as a binder composition for a
positive electrode and a positive electrode related to Comparative
Examples 11 to 13.
[0167] (Manufacture of Negative Electrode)
[0168] To 100 parts of the solid content of the aqueous dispersion
of fine particles of the resin obtained in Comparative Example 5
and the copolymer solutions obtained in Comparative Examples 6 and
7, 4800 parts of mesophase carbon (MCMB 6-28, 5 to 7 .mu.m average
particle diameter, 4 m.sup.2/g specific surface area manufactured
by Osaka Gas Chemicals Co., Ltd.) as an active material for a
negative electrode and 100 parts of acetylene black (furthermore,
30 parts of a tri-functional epoxy resin [product name: Denacol
EX321, manufactured by Nagase ChemteX Corporation] for the aqueous
dispersion of fine particles of the resin obtained in Comparative
Example 5, 50 parts of a tri-functional epoxy resin [Denacol EX321]
for the copolymer solution obtained in Comparative Example 6, and
50 parts of diaminodiphenyl ether [DPE/ODA, manufactured by SEIKA
CORPORATION] for the copolymer solution obtained in Comparative
Example 7), which were dissolved in toluene, were added
respectively, and the mixture was adjusted to have a 50% solid
content in a final binder composition, and kneaded, whereby to
prepare the binder composition for a non-aqueous secondary battery
electrode.
[0169] Furthermore, such a binder composition for a non-aqueous
secondary battery electrode was coated respectively using a doctor
blade on an aluminum foil having 20 .mu.m thickness which served as
a current collector, and then dried by heating under reduced
pressure, and subjected to a milling treatment by a roll press,
whereby to manufacture a negative electrode having a negative
electrode mixture layer having 50 .mu.m thickness.
[0170] The binder composition for a negative electrode and the
negative electrode obtained by such procedures using the aqueous
dispersion of fine particles of the resin obtained in Comparative
Example 5, the copolymer solutions obtained in Comparative Examples
6 and 7 were designated respectively as a binder composition for a
negative electrode and a negative electrode related to Comparative
Examples 11 to 13.
<Assembling of Cell for Evaluation of "Positive Electrode" of
Lithium Secondary Battery>
[0171] A positive electrode previously manufactured (in Examples 22
to 42 and Comparative Examples 8 to 10, Examples 43 to 65 and
Comparative Examples 11 to 13) was punched to a 9 mm diameter,
which was designated as an action electrode, and a metal lithium
foil (0.15 mm thickness) was designated as a counter electrode, and
a separator containing a porous polypropylene film (#2400
manufactured by Celgard LLC) was inserted between the action
electrode and the counter electrode, and laminated, and an
electrolytic solution (non-aqueous electrolytic liquid of
LiPF.sub.6 dissolved at a concentration of 1 M in a mixed solvent
of ethylene carbonate and diethylcarbonate mixed in 1:1) was filled
whereby to assemble a di-electrode closed type metal cell (HS Flat
cell manufactured by Hohsen Corporation). The assembling of the
cell was performed in a grow box substituted with argon gas, and
after the cell assembling, predefined evaluations for battery
properties were carried out.
<Assembling of Cell for Evaluation of "Negative Electrode" of
Lithium Secondary Battery>
[0172] A negative electrode previously manufactured (in Examples 22
to 42 and Comparative Examples 8 to 10, Examples 43 to 65 and
Comparative Examples 11 to 13) was punched to a 9 mm diameter,
which was designated as an action electrode, and a metal lithium
foil (0.15 mm thickness) was designated as a counter electrode, and
a separator containing a porous polypropylene film (#2400
manufactured by Celgard LLC) was inserted between the action
electrode and the counter electrode, and laminated, and an
electrolytic solution (non-aqueous electrolytic liquid of
LiPF.sub.6 dissolved at a concentration of 1 M in a mixed solvent
of ethylene carbonate and diethylcarbonate mixed in 1:1) was filled
whereby to assemble a di-electrode closed type metal cell (HS Flat
cell manufactured by Hohsen Corporation). The assembling of the
cell was performed in a grow box substituted with argon gas, and
after the cell assembling, predefined evaluations for battery
properties were carried out.
<Assembling of Cell for Evaluation of "Positive Electrode" of
Lithium Secondary Battery>
[0173] Using the lithium ion secondary battery electrodes obtained
in the methods (the positive electrode and the negative electrode),
the binding property and the anti-electrolytic solution property
were evaluated, and using the cell for the evaluation of the
lithium ion secondary battery electrode (the positive electrode and
the negative electrode), the battery properties were evaluated.
[0174] (Evaluation for Binding Property)
[0175] On the surface of respective lithium ion secondary battery
electrode, incisions were made using a knife in a depth from the
mixture layer to the current collector at 2 mm interval by 6 pieces
in the longitudinal and horizontal directions respectively to give
a grid incision. To this incision, an adhesion tape was attached
and immediately peeled off, and the degree of dropping off of the
active material was judged by visual judgment. The evaluation
standard is as follows. The evaluation results are shown in Table
4.
[0176] .largecircle.: "No peeling off"
[0177] .largecircle..DELTA.: "Slight peeling off (level of no
practical problem)"
[0178] .DELTA..times.: "Peeling off in almost all portions"
[0179] .times.: "Complete peeling off"
[0180] (Evaluation of Anti-Electrolytic Solution Property)
[0181] Each of the lithium ion secondary battery electrodes was
immersed in propylene carbonate liquid at 70.degree. C. for 24
hours, and the swelling states of the film and the elution states
of the resin before and after immersion were calculated by the
following equations to perform comparative evaluations.
Swelling rate (%)=(weight after immersion)/(weight before
immersion)
Elution rate (%)=(weight after immersion and dry)/(weight before
immersion)-1
[0182] As the value of the swelling rate is closer to 100%, and the
elution rate is closer to 0%, it represents a higher
anti-electrolytic solution property. The evaluation results are
shown in Table 4.
[0183] (Evaluation of Battery Properties)
[0184] The charge and discharge cycle test of a cell for evaluation
of each of the lithium ion secondary battery electrodes was carried
out. When the first electric discharge capacity is assumed as 100%,
the electric discharge capacity after 100 hours at 70.degree. C.
was measured and designated as the change rate (it represents
better as the change rate is closer to 100%). The evaluation
results are shown in Table 4.
TABLE-US-00004 TABLE 4 test EXAMPLE EXAMPLE EXAMPLE EXAMPLE EXAMPLE
EXAMPLE electrode method 22 23 24 25 26 27 binding property
positive tape .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. electrode peeling
negative .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. electrode anti-electrolytic positive
swelling 102% 100% 105% 108% 101% 102% solution property electrode
rate elution -0.80% -0.50% -1.30% -1.10% -0.20% -0.60% rate
negative swelling 101% 105% 102% 105% 103% 104% electrode rate
elution -0.40% -0.60% -1.40% -2.50% -0.30% -0.10% rate battery
property positive after 99.8% 99.9% 97.0% 96.0% 99.9% 99.7%
electrode 100 hours negative at 70.degree. C. 99.6% 99.8% 98.2%
96.2% 98.5% 99.2% electrode test EXAMPLE EXAMPLE EXAMPLE EXAMPLE
EXAMPLE EXAMPLE electrode method 28 29 30 31 32 33 binding property
positive tape .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. electrode peeling
negative .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. electrode anti-electrolytic positive
swelling 100% 100% 103% 110% 108% 111% solution property electrode
rate elution -0.30% -0.50% -0.80% -1.60% -0.90% -1.70% rate
negative swelling 100% 106% 105% 112% 105% 106% electrode rate
elution -0.60% -0.50% -0.40% -2.40% -0.90% -1.10% rate battery
property positive after 99.8% 99.6% 99.7% 98.2% 99.0% 97.9%
electrode 100 hours negative at 70.degree. C. 99.2% 99.5% 99.4%
97.6% 98.1% 97.3% electrode test EXAMPLE EXAMPLE EXAMPLE EXAMPLE
EXAMPLE electrode method 34 35 36 37 38 binding property positive
tape .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. electrode peeling negative .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. electrode
anti-electrolytic positive swelling 101% 103% 110% 105% 108%
solution property electrode rate elution -0.70% -0.90% -1.50%
-1.00% -1.50% rate negative swelling 100% 103% 107% 104% 106%
electrode rate elution -0.40% -0.60% -1.20% -0.80% -1.90% rate
battery property positive after 99.8% 98.9% 97.2% 98.5% 98.0%
electrode 100 hours negative at 70.degree. C. 99.7% 99.0% 97.7%
99.1% 98.8% electrode test EXAMPLE EXAMPLE EXAMPLE EXAMPLE
electrode method 39 40 41 42 binding property positive tape
.largecircle. .largecircle. .largecircle. .largecircle..DELTA.
electrode peeling negative .largecircle. .largecircle.
.largecircle. .largecircle. electrode anti-electrolytic positive
swelling 103% 105% 104% 108% solution property electrode rate
elution -1.50% -0.90% -1.80% -1.50% rate negative swelling 105%
110% 104% 107% electrode rate elution -1.10% -1.90% -0.80% -2.00%
rate battery property positive after 99.1% 98.2% 98.0% 98.0%
electrode 100 hours negative at 70.degree. C. 99.2% 99.2% 99.0%
98.8% electrode test Comp. Comp. Comp. Comp. Comp. Comp. electrode
method 8 9 10 11 12 13 binding property positive tape X
.largecircle..DELTA. X .largecircle..DELTA. .DELTA. X electrode
peeling negative X .largecircle..DELTA. X .DELTA. .DELTA. X
electrode anti-electrolytic positive swelling 106% 187% 321% 271%
280% 363% solution property electrode rate elution -0.90% -12.4%
-28.9% -26.2% -39.8% -40.7% rate negative swelling 104% 208% 247%
249% 302% 256% electrode rate elution -1.50% -20.4% -38.7% -24.4%
-48.0% -33.1% rate battery property positive after 78.0% 85.0%
41.0% 62.0% 65.0% 52.0% electrode 100 hours negative at 70.degree.
C. 70.0% 86.0% 32.0% 71.0% 57.0% 64.0% electrode test EXAMPLE
EXAMPLE EXAMPLE EXAMPLE EXAMPLE electrode method 43 44 45 46 47
binding property positive tape .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. electrode peeling
negative .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. electrode anti-electrolytic positive swelling 100%
103% 102% 105% 100% solution property electrode rate elution -0.30%
-0.80% -0.50% -0.60% -0.50% rate negative swelling 102% 100% 102%
101% 100% electrode rate elution -0.20% -0.10% -0.50% -0.40% -0.70%
rate battery property positive after 99.2% 99.5% 98.0% 99.6% 98.8%
electrode 100 hours negative at 70.degree. C. 99.8% 99.1% 98.9%
99.2% 99.0% electrode test EXAMPLE EXAMPLE EXAMPLE EXAMPLE EXAMPLE
electrode method 48 49 50 51 52 binding property positive tape
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. electrode peeling negative .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. electrode
anti-electrolytic positive swelling 101% 103% 103% 101% 108%
solution property electrode rate elution -0.20% -0.10% -0.40%
-0.40% -1.10% rate negative swelling 101% 101% 102% 101% 104%
electrode rate elution -0.60% -0.60% -0.10% -0.05% -0.90% rate
battery property positive after 99.0% 99.5% 98.9% 99.4% 98.2%
electrode 100 hours negative at 70.degree. C. 98.6% 98.9% 99.0%
99.6% 98.4% electrode test EXAMPLE EXAMPLE EXAMPLE EXAMPLE
electrode method 53 54 55 56 binding property positive tape
.largecircle. .largecircle. .largecircle. .largecircle. electrode
peeling negative .largecircle. .largecircle. .largecircle.
.largecircle. electrode anti-electrolytic positive swelling 112%
106% 102% 105% solution property electrode rate elution -0.90%
-1.50% -0.60% -0.40% rate negative swelling 108% 105% 106% 104%
electrode rate elution -1.60% -1.10% -0.90% -0.60% rate battery
property positive after 97.6% 98.1% 99.1% 99.8% electrode 100 hours
negative at 70.degree. C. 98.0% 98.7% 99.8% 99.6% electrode test
EXAMPLE EXAMPLE EXAMPLE EXAMPLE EXAMPLE electrode method 57 58 59
60 61 binding property positive tape .largecircle..DELTA.
.largecircle. .largecircle..DELTA. .largecircle. .largecircle.
electrode peeling negative .largecircle. .largecircle.
.largecircle..DELTA. .largecircle. .largecircle..DELTA. electrode
anti-electrolytic positive swelling 106% 102% 105% 102% 107%
solution property electrode rate elution -0.70% -0.80% -0.90%
-0.50% -1.40% rate negative swelling 101% 102% 104% 101% 105%
electrode rate elution -0.30% -0.50% -0.70% -0.40% -1.90% rate
battery property positive after 98.5% 99.6% 99.0% 99.8% 98.2%
electrode 100 hours negative at 70.degree. C. 99.9% 98.4% 97.0%
99.6% 99.1% electrode test EXAMPLE EXAMPLE EXAMPLE EXAMPLE
electrode method 62 63 64 65 binding property positive tape
.largecircle..DELTA. .largecircle. .largecircle..DELTA.
.largecircle..DELTA. electrode peeling negative .largecircle.
.largecircle. .largecircle..DELTA. .largecircle..DELTA. electrode
anti-electrolytic positive swelling 110% 103% 110% 111% solution
property electrode rate elution -1.10% -0.60% -1.60% -1.90% rate
negative swelling 102% 107% 109% 109% electrode rate elution -0.90%
-1.60% -1.70% -1.60% rate battery property positive after 99.5%
99.1% 97.0% 96.5% electrode 100 hours negative at 70.degree. C.
99.6% 96.8% 97.3% 96.9% electrode
[0185] As shown in Table 4, when the binder composition for a
non-aqueous secondary battery electrode containing the fine
particles of a functional group-containing cross-linkage type resin
synthesized in Examples 1 to 21 was used (Examples 22 to 65), there
was a balance between the anti-electrolytic solution property and
the binding property, and lowering of the electric discharge
capacity after 100 hours at 70.degree. C. was also suppressed in
the battery properties. On the other hand, when the binder
composition for a non-aqueous secondary battery electrode
containing the fine particles of the resin synthesized in
Comparative Examples 1, 3 and 5, or the copolymers synthesized in
Comparative Examples 6 and 7 were used (Comparative Examples 8 to
13), lowering of the anti-electrolytic solution property or the
binding property was seen, and the deterioration of the battery
properties was also caused. Furthermore, aggregation occurred
during the synthesis of the fine particles of the resin in
Comparative Examples 2 and 4, and thus could not be evaluated.
* * * * *