Note: Descriptions are shown in the official language in which they were submitted.
1141893
-- 1 --
~ his invention relates to novel sulfobetaine-
modified olefinic copolymers which are useful as anti-
static agents and when incorporated into olefinic polymers
or copolymers and other synthetic polymeric materials, can
impart superior and durable antistatic effects without
the need for after-treating the polymeric materials such
as corona discharge treatment and without any deleterious
effect on the properties of the polymeric materials; a
process for producing such copolymers; and to the use of
such copolymers as antistatic agents.
As is well known, olefinic polymers and copoly-
mers and other hydrophobic synthetic polymeric materials
tend to accumulate static charges. Buildup of static
charges causes various troubles such as dust collection
or spar~ing when films, sheets, fibers and other shaped
articles are produced from such polymeric materials, or
when these shaped articles are further processed or treated,
or when the resulting products are in use.
~umerous attempts have been made to prevent
buildup of static charges on hydrophobic synthetic poly-
meric materials, and various antistat~c agents have b~en
suggested and used. However, none of these antistati~
agents have proved to ~e entirely satisfactory, and
investigations are still bein~ undertaken to provide
satisfactory antista~ic agents for such polymeric mate-
rials~
Various suggestions have previously been made as
to betaine-type antistatic agents (see, for example,
11~1893
Japanese Patent Publication Nos. 164~/65, 14654/73 and
29928/?~). Polymeric shaped articles containing these
known betaine-type antistatic agents, however, did not
show the desired antist~tic effect. In an attempt to
obtain a satisfactory antistatic effect, it was suggested,
for example, to ~ctivate the surface of a stretched film
containing a betaine-type antistatic agent by, for ex-
ample, corona discharge treatment (see, for example,
Japanese Patent Publications Nos. 29757/69, 5746/74 and
33827/75). These suggested techniques, however, have the
defect that the surface-activating treatment is complica-
ted and disadvantageous, and the antistatic effect ob-
tained does not last for a sufficient period of timeO
The present inventors worked extensively in
order to develop antistatic agents which can obviate the
need for surface-treating shaped articles of synthetic
polymeric ~aterials containing the antistatic agents
contrary to the case of using known betaine-type antista-
tic agents, and show antistatic effects that last for a
sufficient period of time.
As a result, the inventors found that the novel
sulfobetaine-modified olefinic copolymers not described
in the literature can be produced as will be described
hereinbelow5 and these copolymers show excellent ability
to prevent buildup of static charges, completely r~moving
the defects of the conventional betaine-type antistatic
agentsO It was specifically fo~nd that these sulfobetaine-
modified olefinic copolymers show sufficient long-lasting
~ 41893
antistatic effects in synthetic polymeric materials with-
out the need for a surface-aetivating treatment, and d~
not cause adverse effects on the desirable properties of
the synthetic polymeric materials contrary to the conven-
tional betaine-type antistatic agents. It has thus been
found that these antistatic agents of the invention can
impart excellent and long-lasting antistatic effects to
synthetic polymeric materials without the need for a com-
plicated and disadvantageous surface-activ~ting treatment,
and have the ~dvantage that they do not degrade the anti-
blocking properties of poly~eric shaped articles such as
films or sheets nor their printability, gloss or other
surface characteristics, and do not render their surfaces
tacky.
It is an object of this invention therefore to
provide novel sulfobetaine-modified olefinic copolymers.
Another object of this invention is to provide a
process for producing such copolymers.
Still another object of this invention is to
provide the use of such copolymers as antistatic agents
for synthetic organic polymeric materials.
The above and other objects and advantages of
this invention will become more apparent from the follow-
ing description.
he sulfobetaine-modified olefinic copolymer of
this invention is an olefinic copolymer having a number
average molecular weight (~n) of ~bout 500 to about
100,000 and derived from a major proportion of an ~-olefin
11~1893
containing 2 to 6 carbon atoms and a minor proportion of
a comonomer selected from the group consisting of unsat-
urated carboxylic acids containing 3 to 12 carbon atoms,
the functional derivatives thereof, unsaturated esters
of carboxylic acids containing 4 to 12 carbon atoms and
unsaturated amines containing 3 to 9 carbon atoms, with
the moiety derived from the comonomer having chemically
bound thereto a sulfobetaine group of the following
formula
R3 R4
-X-Rl _ N~-R2 _y -so3G~
wherein Rl represents an alkylene group containing 1 to 12
carbon atoms, R represents an alkylene group con*aining
1 to 3 carbon atoms, R3 and R4 each represent a member of
the class consisting of a hydrogen atom, alkyl groups con-
taining 1 to 10 carbon atoms, polyoxyalkylene groups con-
taining 2 to 6 carbon atoms, hydroxyalkyl groups contain-
ing 1 to 6 carbon atoms, carboxyalkyl groups containing
2 to 4 carbon atoms and carboxylate alkyl groups containing
2 to 4 carbon atoms, X represents an oxygen atom, a carbonyl
group, an ester bond, an amide bond or a methylene group,
and Y represents an oxygen atom or a methylene group.
As antistatic compounds which most resemble the
sulfobetaine-modified olefinic copolymers of this inven-
tion, Japanese Laid-Open Patent Publication No. 31027j77
(laid open on March 9, 1977) discloses compounds formed
11~1893
by reacting a tertiary ~mine-containing vinyl monomer of
the formula
(cH2)n-l F~ Rlo
I. CH2=C-CO-Y_A-N-R
(~12in-l R2
II. C~2=C-Z-CII2-N-R3
( CH2 ~n-l
III. CH2=C ~ ~
wherein Y represents -O- or -~I-, A re~resents
an alkylene group containing 2 to 6 carbon
atoms, Z represents -O-, an alkylene group
containing 1 to 6 carhon atoms or ~ phenylene
o~ Rl, R2, and R~ represents an
alkyl group containing 1 to 4 carbon atoms, n
is an integer of 1 to 4, and m is an integer of
2 to 4,
with the reaction product formed between a mono-, di-, or
1~ trihalogenated acetate and a sultone of the following
formula
IV. 4CH2)m~o3
wherein m is as de~ined above.
It is stated in this Publication that portion
of the final compound which contains a moiety derived from
the sultone and bonded to the auaternary nitrogen atom has
1~4~893
any one of the following structuresO
~ CH2COO(CI~2~n~C~Me.
-N-cH-coo(cH2)n5
~ c-coo(cH2)n5o3~Ie
(Me represents a metal atom constituting the
acetate).
~he sulfobetain~-modified oléfinic copolymers of this
invention are distin~uished from these suggested compounds
in that the corresponding portion of these copolymers has
the following structures.
-N_(cl-C3 alkYlene)~CH2 S3
C~' (Cl-C~; alk91ene)_o_so3 ~
Furthermore, as will be shown in Comparative Example 11,
the compounds suggested in the above-cited Publication do
not show the excellent antistatic properties possessed by
the sulfobetaine-modi~ied olefinic copolymers of this
invention.
The sulfobetaine-modified olefinic copolymer of
this invention has a sulfobetsine group of the above
formula which is bonded chemically to the moiety derived
from the comonomer of an olefinic copolymer having a
number average molecular weight, measured by a vapor-
11~1893
pressure osmometer, of about ~00 to about 100,000. Thecopolymer preferably has a number average molecular
weight of about 800 to about 25,000. If the number
average molecular weight is less than about 500, it will
bleed out or become sticky on the surface of a shaped
article prepared from a composition composed of a syn-
thetic polymeric material and the sulfobetaine-modified
olefinic copolymer. Or the sulfobetaine-modified
olefinic copolymer tends to be dissolved easily when such
a shaped article comes into contact with water or
solvents. Hence, the durability of the antistatic effect
is aggravated. Gn the other hand, when the number
average molecular weight is higher than about 100,~00,
it is difficult to disperse the sulfobetaine-modified
olefinic copolymer uniformly in a synthetic polymeric
material, or it does not easily impart a sufficient
antistatic effect. Or the appearance of a shaped article
containing it becomes poor.
Examples of the ~-olefin containing 2 to 6
carbon atoms from which the olefin copolymer having a
number average molecular 1~eight of about 500 to about
100,000~ preferably about 800 to about 25,000, is derived
are ethylene, propylene, l-butene, and 4-methyl-1-pentene.
~he~ can be used either singly or as a mixture of two
or more D ~he comonomer includes, for example, unsaturated
carboxylic ~cids containing 3 to 12 carbon atoms such as
acrylic acid, methacrylic acid, ~-ethylacrylic acid,
atropic acid, crotonic acid, maleic acid, fumaric acid,
1141893
itaconic acid, citraconic acid, undecylenic acid and
5-norbornene-2,3-dicarboxylic acid; and their functional
derivatives. Examples of such functional derivatives
include the anhydrides such as maleic anhydride, itaconic
anhydride and citraconic anhydride; the mono- or di-alkyl
esters (preferably C4-C18 alkyl esters) such as methyl
acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,
methyl methacrylate, ethyl methacrylate, dimethyl maleate,
dimethyl fumarate, monoethyl fumarate, diethyl itaconate,
monomethyl itaconate, dimethyl citraconate, and
5-norbornene-2,3-dimethylcarboxylate; and aminoethyl esters,
aminopropyl esters, mono- or di-alkyl aminoethyl esters
and dihydroxyalkylamino ethyl esters of the aforesaid
unsaturated carboxylic acids such as aminoethyl meth-
acrylate, N-methylaminoethyl methacrylate, N,N-diethyl-
aminoethyl methacrylate, N,N-dihydroxyethylaminoethyl
methacrylate, aminoethyl acrylate, N-ethylaminoethyl
acrylate, N,N-diethylaminoethyl acrylate, N,N-dihydroxy-
ethylaminoethyl acrylate, diaminoethyl maleate,
di-N-ethylaminoethyl maleate, and di-N,N-diethylamino-
ethyl maleate. The alkyl group of the alkylaminoethyl
esters or hydroxyalkylaminoethyl esters preferably con-
tains 1 to 6 carbon atoms.
Other examples of the comonomer include unsat-
urated esters of carboxylic acids containing 3 to 12
carbon atoms such as vinyl aceta~e, allyl acetate and
undecenyl acetate; and C3-Cg unsaturated amines selected
from alkenylamines, N-alkylalkenylamines, N,N-dialkyl-
il4~893
g
alkenylamines, N-hy~roxyalkylalkenylamines ~nd N,N-
dihydroxyall~ylalkenylamines, typified by allylamine,
I~,N-dimethylallylamine, N,N-~iethylallylamine, I~-hydroxy-
ethylallylamine, and N,N-dihydroxypropylallylamine.
Preferably, the hydroxyal~yl group contains 2 to 6 carbon
atoms and the alkenyl group contains 3 to 9 carbon atoms.
Preferred comonomers are acrylic acid, its
derivatives, methacrylic acid, its derivatives, and N,N-
diethylallylamine.
These comonomers can be used either singly or
as a mixture of two or more.
~ he olefinic copolymer which cor.stitutes the
basic part of the sulfobetaine-modified olefinic copoly-
mer of this invention may be any of random, block, and
1~ graft copolymers. Conveniently, a ma~or proportion of
the basic part is a moiety derived fron an a-olefin con-
taining 2 to 6 carbon atoms as exemplified hereinabove.
Preferably, for this purpose, the olefinic copolymer
which constitutes the basic part comprises about 30 to
about 99 mole~', more preferably about 40 to about 95
mole~, of a moiety derived from the a-olefin~ and the
remainder consisting of a moiety derived from the comonomer.
~xamples of the basic part are olefinic copoly-
mer portions havin~ a moiety resulting ~rom the graft-
copolymerizing of the aforesaid comonomer with a homopoly-
mer of an a_olefinc such as polyethylene, polypropylene7
polystyrene, poly-l-butene and poly-4-methyl-1-pentene
or a copolymer of an ~-olefin such as an ethylene/pro-
1~41893
pylene copol~ er, an ethylelle/l-butene copol~er, an
ethylene/4-methyl-1-pentene copolymer, an ethylene/bu-
tadiene copolymer, an ethyleile~propylene/diene copolymer,
a propylene/l-butene copolymer, a propylene/4-methyl-1-
pentene copol~ er c~nd an ethylene/vinyl acetate copolymer;olefinic copolymer portions containing a moiety derived
from the aforesaid comonomers and resulting from the block
copolymerization of the polymers or copolymers exemplified
above and polymers or copo3.ymers derived from the above-
exemplified comonomers; and random copolymers havi~g amoiety derived from the above-exemplified comonomers such
as an ethylene/acrylic acid copolyTner, an ethylene/methyl
acryl?Ate copolymer, an ethylene,~ethyl methacrylate co-
polymer, an ethylene/methyl methacrylate copolymer, a
propylene/N N-diethylaminopropyl methacrylate copolymer,
and a styrene/N,N-dimethylaminoethyl methacrylate copoly-
merO
~ he sulfobetaine-mo~lified olefinic copolymers
of this invention has a sulfobetaine group of the formula
R3 R4
-~-Rl- N~-R2-Y-S03 ~
chemically bound to the moiety derived from the aforesaid
comonomer of -the olefinic copolymer.
In the formula, Rl represents an a3kylene group
containing 1 to 12 c~rbon atoms, preferably an alkylene
2~ group containing 1 to 6 carbon atoms; R2, an alkylene
group containing 1 to 3 carbon atoms; each of R3 an~ R4,
1~41893
a member sel~cted from the class consisting of ai hydrogen
atom, alkyl groups containin~ ]. to 10 c~rbon atoms, pre-
ferably 1 to 4 carbon atoms, ~olyoxyalkylene groups con-
t~ining 2 to 6 carbon ~toms, hydroxyalkyl groups contain-
in~ 1 to 6 carbon atoms, carboxyalkyl groups (-RCCOH in
which R represents a Cl-C10, preferably Cl-C4, alkyl
group) and C2-C4 carboxylate alkyl groups (-RCC'OM in
which R is as defined and ~ represents ~ metal atom such
as Na, K, Zn, Ca, ~a, Sr. Pb, Mg or Al), preferably ex-
clu~in~ hy~rogen; X, an o~ygen atom, a carbonyl group,an ester bond, an amide bond or a methylene group, pre-
ferably an oxygen ato~, ~n ~ster bond or a methylene
group; and Y, an oxygen atom, or a methylene group, pre-
ferably the latter.
~referably, R2 and Y in the above formula of
the sulfobetaine group are both methylene groups,
Specific ex~mples of the sulfobetaine ~roups
are listed belowO
-CcH2cH2 ~ CH -CC`OCE2CH2
N 3 ~ N ~ 3
I ` CH3 C~ '~ CH
3~ ~ SO3 / CH2
C~I2-CH2 , CH2
-CCOCH2CH2 CH CCOC 2 2 CH
N / 3 ~ ~ / 3
I `CH ~ I CH3
CH2 3 ~ I
S03 / C~2 O - CH2
CH2-CH2
114189;~
-- 12 --
-COOC}I2CH2 CH -COOCH2CH2 CH
~? N ' 3 ~ N ~ 3
CH ~ CH
CX2 3 CH2 3
:3 ' ~ I
SC 3 CH2 S~3 / CH2
P-CH2 . n-CH2
-CCOCH2CH2 -CCOCH2CH2
C~,H ~ C H OH
~;~ N/ ' 5 ~3 N' 2 4
C-3 ' C2H C-) ' C2H40H
SO 3CH2 5 SO 3~C, H2
CH2-CH2 , CH2-CH2
-COOCH2CH2 -COOCH2CH
X2CX2(:))2H CH2COCTI
N' ~)N'
( CH2CH2C) ) 2H ~? ~ CH2COOH
SO3~ C,H2 SO3~ C,H2
CH2-CH2 CH2-CH2
CH
1 3
-COOCHCH2 -CCOCH2CH2
C H OH ~ CH
~)N~ 2 4 (~N' 3
C~ I ` C2H4H ~? ' C2H40H
SO 3 ~ ,C 2 SO 3 C, H2
CH2-CH2 ' CH2-CH2
1~ 4~893
- ~ocH2cEI, -COCH2CH
N ~ ~ M ' 3
I C,,II40H i3 ' CH2COOH
SO- 31CH2 3 C, ~I2
` CH2-CH2 CH2-C'I2
-COCH2CH2 -CCH2C~'~2
~N~ 2 5
' CHz ~? l ~C2H
SO 3CH2 ' S~) 3 CH2 5
C~12-C~I2 , CH2-CH2
-CCCH2CH2 -CCCH CY
~3 N~C 22 2~ ~(CH2cH2c')2H
CH;?COOH ~ I ( C~I2CH2C ) 2H
SO c~2 -SO 3~ C, TI2
CH C H C~2-C~2
-CH2CH2CH2-CH2C~2C~2
~ N'~ N ' 2 5
(~ I CH ~! ' ` C H
SO 3 CH2 3 3 CH2 2
CH2-CH2 ~ CH2-CII2
-CH2CH2CH2 -CH CH CH
,C2 402 2 2` (CH2cH2)2H
C2H40H 3 1 ( CH2CH2C ) 2H
SG C T'[ SO C, H2
CH2-C~2 C~2-C~I2
1~1893
- 14
-C~2CH2CH2 CCl~-I(CH )
CH COCH ~ ,Ch3
~ N~ 2 ~ N~
9CHCH2 SC3 ' CH~
CH2-CH2 C 2 C 2
-CONH(CH2~6 -CG~I(CH~)~
/(C~I2C~2C)2H'- \ CH COOH
(~ I (CH2CH20~2H ~ I CE~2COOH
S03 CIH2 S03~ C,~12
CH2-CH2 CEI2-C~2
~!~.N ~+`N~(CH2cl~2)2H
CEI~ ~ I (C~2CH2C~)2H
` CH2-C~I2 CH2-CH2
-COI~(CH2)12
~CH2COO~a
N
~_) I CH2COCNa
S03 ClH2
CH2 CH2
In preferred examples of the sulfobetaine-
modified olefinic copolymer of this invention, the ~mount
of the sulfobetaine group is generally about 0.01 to
about 6 millimoles, preferably about Ool to ~bout 5 mil-
limoles, per @ram of the sulfobetaine-modified olefinic
copo lymer .
~he sulfobetaine-modified olefinic copolymer
" ~1418~3
of this invention can be prepared easily by the following
methods, for example.
(a) A sulfobetaine-modified olefinic copolymer in
which X in the formula represents an ester bond can be
prepared by reacting a copolymer of an -olefin having
2 to 6 carbon atoms and a C3-C12 unsaturated carboxylic
acid or its functional derivative, or a graft copolymer
resulting from the graft copolymerization of a homo- or
copolymer of the a-olefin with a C3-C12 unsaturated
carboxylic acid or its functional derivative, with an
alkanolamine containing 4 to 9 carbon atoms such as N,N-
dimethylethanolamine, and reacting the reaction product
further with a C2-C4 sultone such as 1,2-ethanesultone,
1,3-propanesultone or 1,4-butanesultone or a C2-C4 cyclic
alkylene sulfate such as ethylene sulfate l-methyl-
ethylene sulfate or 1,3-propylene sulfate.
(b) A sulfobetaine-modified olefinic copolymer in
which X in the formula represents an oxygen atom can be
produced by reacting a copolymer of an a-olefin having 2
to 6 carbon atoms and a C4-C12 carboxylic acid unsaturated
ester, or a graft copolymer resulting from the graft-co-
polymerization of a homo- or copoIymer of the olefin with
a C4-C12 carboxylic acid unsaturated ester, with a C4-Cg
alkanolamine, and reacting the reaction product further
with a C2-C4 sultone or a C2-C4 cyclic alkylene sulfate.
(c) A sulfobetain-modified olefinic copolymer in
which X in the formula represents a methylene group can
be prepared by reacting a copolymer of an a-olefin having
- 15 -
i~4~893
- ~6 -
to 6 carbon ~toms and an N,I~-dialkylalkenylamine, or a
~raft copol~er re~sulting frori the graft-copolymerization
o~ a homo- or copolymer of the Q-olefin with the I~,N-di-
alkylalXenylamine, with a C2-C4- sultone or a C2-C4
cyclic alkylene sulfate.
(~) A sulfobetaine-modified olefinic copolymer in
which X in the formul3 represents an amide bond can be
prepared by reacting a copolymer of an ~-olefin having 2
to 6 carbon atoms and a C3-C12 unsatur?ted carboxylic
acid or its acid anhydride, or a graft copolymer resulting
from the graft-copolymerization of a homo- or copolymer of
the a-olefin with the uns~turated carboxylic acid or its
acid anhydride, with an N,N-dialkylalkylenediamine or an
N,N-dihydroxyalkylalkylenediamine, followed optionally by
addition-reaction of an alkylene oxide containing 2 to 4
carbon atoms; and reacting the reaction product with a
C2-C4 sultone or a C2-C4 cyclic alkylene sulfateO
~ he base polymers used in processes (a) to (d)
are produced by, for example, radical polymerization in
the presence or absence of a solvent under atmospheric or
elevated pressures~ The reaction with the alksnol~mine
or alkylenediamine is ef~ected by dissolving the base
polymer in a hydrocarbon solvent such as p-xylene, and
heating the mixture in the presence or absence of an
esterification, ester-interchange or dehydrating catalyst.
~he reaction with the sultone or cyclic sulfate proceeds
by gradually ad~ing the sultone or cyclic sulfate to the
aforesaid reaction product at an elevated temperature.
1141893
According to this invention, there can also be
provided a method for static prevention of a synthetic
polymeric material by incorporating an antistatically
effective amount of the sulfobetaine-modified olefinic
copolymer of the invention into the polymeric material;
and an antistatic composition of a synthetic polymeric
material containing an antistatically effective amount
of the sulfobetaine-modified olefinic copolymer.
Examples of synthetic polymeric materials which
are to be rendered antistatic in accordance with this
invention include olefin polymers or copolymers such as
polyethylene, polypropylene, poly-l-butene, poly-4-methyl-
l-pentene, polystyrene, an ethylene~propylene copolymer,
an ethylene/l-butene copolymer, an ethylene/4-methyl-1-
pentene copolymer and an ethylene/vinyl acetate copolymer;
polyamides and copolyamides; polyesters and copolyesters;
polyvinyl chloride; polycarbonates; and ABS resin, AS
resin, acrylic resins and acrylonitrile resins. Especially
favorable results can be obtained when the sulfobetaine-
modified olefinic copolymers of this invention are in-
corporated into homo- or copolymers of a-olefins contain-
ing 2 to 6 carbon atoms.
The antistatic agent of this invention may be
added to these synthetic polymeric materials by any
desired methods. For example, a method can be employed by
which the antistatic agent and other optional additives
are added in specified concentrations uniformly to a
powder or pellets of the polymeric material. Or a master
- 17 -
1141893
batch of a synthetic polymeric material containing the
antistatic agent in a high concentration is prepared in
advance, and added to the polymeric material. In some
case, the antistatic agent may be added during the poly-
merization of the olefinic monomers. Any known means of
addition can be used, and for example, mixing can be
performed by using rolls, mixersJ or extruders. If
desired, the antistatic agent may be added as a solution
in a solvent, and the solvent is removed afterward by
distillation.
The proportion of the antistatic agent used in
this invention differs according to the type of the anti-
static agent, the content of the sulfobetaine group,
and the type and end use of the synthetic polymeric mate-
rial. It is generally about 0.01 to about 300 millimoles,
preferably about 0.05 to about 100 millimoles, as the
sulfobetaine group per 100 g of the synthetic polymeric
material.
The antistatic synthetic polymeric composition
comprising a synthetic polymeric material and an anti-
statically effective amount of the sulfobetaine-modified
olefinic copolymer of this invention may further include
at least one additive selected from antioxidants, ultra-
violet light absorbers, lubricants, plasticizers, mold
releasing agents, fire retardants, fillers, coloring
agents and other antistatic agents.
The antioxidants include, for example, 2,6-di-
tert-butyl-p-cresol, tetrakis[methylene-3-(3',5'-di-tert-
- 18 -
~141893
butyl-4'-hydroxyphenyl)propionate]methane, and dilauryl
thiodipropionate, and are added in an amount of up to
about 2% by weight, for example, about 0.01 to about 2%
by weight, based on the weight of the synthetic polymeric
material.
The lubricants include, for example, calcium
stearate, butyl stearate and polyethylene wax, and are
added in an amount of up to about 5% by weight, for
example about 0.01 to about 5% by weight, based on the
weight of the synthetic polymeric material.
The plasticizers include, for example, dibutyl
phthalate and dioctyl phthalate, and are added in an
amount of up to about 150% by weight, for example about
10 to about 150% by weight, based on the weight of the
synthetic polymeric material.
The mold releasing agents include, for example,
silicones, and are added in an a unt of up to about 5~
by weight, for example, about 0.01 to about 5% by weight,
based on the weight of the synthetic polymeric material.
Examples of the fire retardants are diphenyloctyl
phosphate, tetrabromobenzene, antimonous trioxide, and
tris(2,3-dibromopropyl) phosphate. They are added in an
amount of up to about 50% by weight, for example about 0.1
to about 50% by weight, based on the weight of the syn-
thetic polymeric material.
Examples of the other antistatic agents which
may be used together with the antistatic agent in ac-
cordance with this invention include N,N-bis(2-hydroxy-
- 19 -
~ 41893
ethyl)dodecylamine, N,N-bis~2-hydroxyethyl nostearate)
octadecylamine, and N-hydroxyethyl-N-sodiocarboxymethyl-
octadecyl betaine. They are added in an amount of up to
about 3% by weight, for example about 0.01 to about 3% by
weight, based on the weight of the synthetic polymeric
material.
The ultraviolet absorbers are, for example,
nickel dibutyl dithiocarbamate, 2-hydroxy-4-methoxy-
benzophenone, and bis(2,2,6,6-tetramethyl-piperidinyl-4)
sebacate, and are added in an amount of up to about 1%
by weight, for example about 0.01 to 1% by weight, based
on the weight of the synthetic polymeric material.
The fillers include, for example, mica,
silicates, and diatomite-kiesel-guhr, and are added in
an amount of up to about 100% by weight, for example
about 1 to about 100% by weight, based on the weight of
the synthetic polymeric material.
The coloring agents are, for example, titanium
dioxide and ferric oxide, and are added in an amount of
up to about 5% by weight, for example, about 0.1 to about
5% by weight, based on the weight of the synthetic poly-
meric material.
The synthetic polymeric composition containing
the antistatic agent in accordance with this invention
can be shaped into articles of various configurations.
~or example, it can be formed into films, stretched films,
tapes, stretched tapes, sheets, fibers, and other solid
shaped articles. Preferably, the polymeric composition
- 20 -
'~^
~41893
containing the antistatic agent of the invention is shaped
into fibers or stretched or unstretched films or sheets.
These shaped articles are characterized by the
fact that they show an excellent antistatic effect without
being subjected to a special surface treatment such as
corona discharge treatment, and the antistatic effect is
long-lasting because the antistatic agent does not dis-
solve when such shaped articles come into contact with
water or solvents. They further have the advantage that
the incorporation of the antistatic agent of the inven-
tion does not degrade the properties of the base polymer
such as its antiblocking property, surface printability
or surface gloss, nor does it cause the surfaces of the
shaped articles to become tacky.
The following Examples taken in conjunction with
Comparative Examples more specifically illustrate the
production of the sulfobetaine-modified olefinic copoly-
mers of the invention and their utilization as antistatic
agents.
Example 1
Ninety (90) grams of a random copolymer ~a
number average molecular weight (Mn) = 8,000~ of ethylene
and N,N-dimethylaminoethyl methacrylate was dissolved in
1,000 g of p-xylene, and then 40 g of 1,3-propanesultone
was added. They were reacted at 135 C for 2 hours. The
reaction mix~ure was put into methanol to precipitate the
product, followed by purification to afford a sulfobetane-
modified olefinic copolymer (designated "antistatic agent
- 21 -
114~893
A"~ which was found to have a sulfobetaine group content
of 1.5 millimoles/g, a number average molecular weight of
9,300, a density of 1.04 g/cc and a melting point of
109C. The number average molecular weight ~Mn) was
measured by a vapor pressure osmometer; the density, by a
density gradient method; and the melting point, by a
differential scanning calorimeter made by Perkin-Elmer
Company. The same methods of measurements were used in
the following examples.
The sulfobetaine-modified olefinic copolymer
contained the following units.
~CH2 -CH
CH3
2-C
CooCH2CH2N(CH3)2
m
H3
CoocH2cH2 N(CH3)2-(CH2)3S3 J
Q
(n:m:Q=17:0.6:1.4)
Example 2
The procedure of Example 1 was repeated except
that a copolymer (Mn=5,000) of ethylene and N,N-diethyl-
aminoethyl methacrylate was used as the base polymer.
- 22 -
1~41893
- 23 -
~ sulfobetaine-modified clefinic copol~er was obtained
which had a sul~obet~in group content of 0.8 millimole/g,
a number aver~ge molecul~r weight of 5,~00, a density of
1-03 g/cc and ~ melting point of 10~C (designated
"antistatic agent B").
The sulfobetaine-modified olefinic copolymer
contained the following units.
CH2-C~2~--
~ CH3
- ! CH2-C _
COOCH2CH2N(C2H5)2
m
CH3
- -CH -~ t
CoocH2cH2N(c2H5)2-(cH2)3so3 J
(n:m:~=12:0.1:0O4)
ExamPle 3
Twenty grams of a copolymer (~n=25,000) of
ethylene and ethyl acrylate was dissolved in 200 g of
p-xylene. ~he solution was heated to ~C, and 0.1 g o~
sodium methylate and 13.6 g of N,N-dimethyl ethanolamine
were added dropwiseO After the addition, they were re~ct-
ed for 4 hoursO The unreacted eth~nolamine was removed,
and then 3.4 g of 1,3-propanesultone was added and reacted
` ~141893
_ ~4 -
at 135C for 2 hours. The product was purified to afford
a sulfobetaine-modified olefinic ccpolymer (designated
"~ntistatic agent C") which w~s found to have ~ sulfo-
betaine group content of 0.5 millimole/g, a number average
molecular weight of 29,000, a density of 1~04 g/cc and a
melting point of ~4C.
The sulfobetaine-modified olefinic copolymer
contained the following units.
~ CH2-CH
10t C~2 Cl ~
COOCH2C~2N(CH3)2 J
m
~ CH2-~H , I
¦ CC0CH2CH ~(cH3)2-(C~2~3$3
(n:m:~=17:0.1:0.3)
Example 4
~hree hundred grams of polyethylene wax (~n-
2,500) was melted at 140C, and with strong stirring,
156.6 g of N,N-diethyl allylamine and 6 g of di-tert-
butyl peroxide were ~dded. They were re~cted for 6 hours,
c~nd the reaction product was dissolved in 4,000 g of p-
xylene, and 122g of 1,3-propanesultone w~s added and
reacted at 135C for 2 hoursO ~he product was
purified to form a sulfobetaine-modified olefinic co-
~4~893
- 2~ -
pol~er in which -CH2(CH2)2~(C2H5)2 ( 2 ? 3 3
cally bound to the moiety of polyethylene. The modified
copolymer was found to have a sulfobetaine group content
of 0.7 millimole/g, a number average molecular weight of
3,100, a density of 1003 g/cc and a melting point of
128C. ~he modified copolymer is desi~nated "antistatic
agent D".
ExamPles 5 to 8 and Comparative Example 1
~o 100 parts by weight of polypropylene powder
(having a density of 0.91 g/cc, a melt index of 1.0 g/lQ
min., and a melting point of 165C was ad~ed each of an-
tistatic agent A (Example 5), antistatic agent B (Example
6), antistatic agent C (Example 7) or c~ntistatic agent
(Example 8~ in an amount of 1.5, 1, 2, or 3 parts by
weight respectively, and they were mixed by a Henschel
mixer. The mixture was pelletized t~ form polypropylene
pellets containing the antistatic agent.
~ he pellets were molded into films by an in-
flation molding machine to form film I ~containing 1.5
parts by weight of antistatic agent ~ (Example 5)~, film
II ~containing 1 part by weight of antistatic agent B
(Example 6)~, film III ~containing 2 parts by weight of
antistatic agent C ~Example 7)~, and film IV tcontaining
3 parts by weight o~ antistatic agent D (Example 8)~.
In the same way as above, polypropylene pellets
containing no antistatic agent were molded into a film
tdesignated film V (Comparative Example 1)~
~hese films were allowed to stand for a week in
1141893
- ~6 -
a constant temperature-constant humidity cha~lber at 25C
and 60:~ RH, and then their surface resistivities were
measured by using a surface resistivity measuring device
(TR-42, made by Taked~ Riken Co., ~td~)o The results are
shown in Table 1.
Table 1
ExampleSample Antistatic agent Surface resistivity
Type Amount (ohms)
wèight)_
~ilm I A 1.5 1.0 x 101
6 Film II B 1 1.0 x 1012
7 Film III C 1 5.0 x 1011
8 Film IV D 3 5O0 x 101
_
Comparative 17
Example 1 ~ilm V Not added above loO x 10
Examples 9 and 10 and Comparative ~xample 1
Gne hundred parts by weight of polypropylene
pellets having a density of 0.91 g/cc, a melt index of
1.0 g/10 min. and a melting point of 165C were uniformly
mixed with 1 part by weight of c~ntistatic agent A by a
Henschel mixer, and then pelletized to form polypropylene
pellets containing the antistatic agent (Example 9).
In the same way as above, 100 parts of poly-
ethylene pellets having a density of 00954 g/cc, a melt
index of 0O9 g/10 min. and a melting point of 131C were
mixed uniformly with 2 parts by weight of antistatic agent
B~ and pelletized to form polyethylene pell.ets containing
~14i893
-- ~7 -
the antist~tic agent (h~xample 10).
~hese pellets were molded into films by using
an inflation molding machine to obt~in film VI (~xample
9) and film VII (~xP~ple 10).
In the same way as above, the same polyethylene
pellets as used in Ex~mple 10 were molded into a film
without adding any antistatic agent to form film VIII
(Comparative Example 2)o
These films were allowed to stand for 2 days in
a constant temperature-constant humidity chamber at 25C
and 60/v RH, and their surface resistivities were measuredO
The results ~re shown in T~ble 20
_able 2
Example Sample Base Antistatic agent ~ur~ace re-
polymer l~I~e Amount sistivity
(parts by (ohms)
9 Film VI Poly- 11
propylene A 1 5.0 x 10
Film VII Poly- 10
ethylene 2 5.0 x 10
Compa- Poly- above
rative Film VIII ethylene Not added 1.0 x 10 7
Example 2
i
Example 11 and Comp~rative Examples 3 to 6
One hundred parts by weight of polypropylene
powder having a density of OD91 gicc, a melting point of
165C and a melt index of 1.0 g/10 minO was mixed uni-
fo~mly with 1 part by weight each of antistatic a~ent A
~Example 11) ~nd the four commercially available antistatic
1~41893
2 ,C~,
agents indicated in Table 3 (Comparative Examples 3 to 6
by a Henschel mixer, and then pelletized to form pellets.
~ he pellets were folw~ed into sheets by an ex-
truder fitted with a sheet-forming die, and then stretched
to 5 times their original dimension both in the machine
and transverse ~irections. ~hese biaxially oriented films,
either as such or ~fter having been subjected to corona
discharge treatment, were allowed to stand for 2 dc~ys in a
constant temperature-constant humidity cha~mber at 25C and
60' RH, and then their surface resistivities were measured.
The results are shown in Table 3.
Table 3
Surface resistivity
Antistatic agent (ohms)
Corona Corona
disch~rge discharge
performed not
_ _ _ performed
Example 11 Antis.~atic ageht A 2.0 x 1011 4~0 x 1011
__ _ ._ .
Comparative 11 above
Exa~ple 3 lauryl betaine 1.0 x 10 1.0 x 10 7
_.
Comparative hydroxyethyl-
Example 4 sodiocarboxymethylalkyl 500 x 101 above 17
Compar~tive alkyl betaine above
Example 5 2.0 x 1011 1.0 x 1017
_ . .. ~
Ccmparative dimethyl alkyl betaine 12 above 17
~xc~mple 6 ._.......................... 1~0 x 10 1.0 x 10
Example 12 and Comparative Examples 7 to 10
~he corona discharge-treated films obtained in
Example 1 and Comparative Exa~ples 3 to 6 were e.~ch
-` 1141893
29 --
extracted for ? hours with water, heptane an~ ethanol at
their boiling points, and then dried under reduced pres-
sure. ~he dried films were allowed to stand for 2 days
in a constant temperature-constant hu~lidity chamber at
25 C and 6~' RH, and their surface resistivities were
measured~ The results are shown in Table 40
41893
-- 30
_ _ ,, ~o , ~o, ~o ~o ~o
i x j~xl ~ x, ~x l~x
~ 1~1 O I G O O O ¦ O O O O
~ ~ OJ ~ I ~ r O rt~ ~
~0 ~ _ I
~ ~n ~ C~ ~ r~ c~
~ ~ ~0 ~3 ~0 ~0 ~0
5 ~ h ~! ~ ~ ~1 ~1
rl ~ ~3 X I ~X I ~ X ~X ~,X
u~ ~S 3 O 00 1 o 5 oO oO
~1 h u~ ~ ~ ¦ ,~ o 0 ~1 0 ~
h 1~ _ ¦ _ __
J Q) ~J C~ C' C'
C~ ~) ~1 i ~1vl ~1 ~1
Q~ ¢ ~ O ~ O O O O
~ h ~, ~J I ~1 r 1 ~i ~
E~ ,~ ~ X I ~ X ~ X ~ X ~ X
~ O 00 O O 00 oO
_ _ ~I ~ ~ ~_ ~ ~
~ I ~ .~
I I.,0, ~ ~
,o
~ 0~ .~ $~ ~
~ C) ~ j0 0
4 rl c~ ! ~ a) ~ l
~ 0 r~l ¦ X X J~ I S
~ 'q P~ , O O r~ ~1 ~
cl; t~i ¦ h 0 a~ r~l r~/
r-l ,!;~ C),O Ll~ ~
o
I ~ I . co ~, ~ ! r
5 a) CG
~1 h~ hrl I hr~ h~l
C;, ~ , ~'V ~, ~
~ r7j ~ ~
X c~ X ! G X I O X O ~ i
~1 1 V ~ I V ~1 ! v ~ ~
11 41893
Example 13
A copolymer of ethylene and N,N-dimethylamino-
ethyl methacrylate (Mn=8J000; N content 1.7 millimoles/g)
was dissolved in p-xylene, and 1,3-propanesultone was
added and reacted at 130C for 3 hours. The reaction
product had a sulfur content of 2.9% by weight and
a sulfobetaine group content of 0.91 millimoles/g,
and contained the following units.
~CH2 -CH2)n
CH3
lCH C \ / (CH ) SO oJ
~n:m=20:1)
One hundred parts by weight of polypropylene
having a density of 0.91 g/cc, a melt index of l.S g/10
min., and a melting point of 165C was mixed with 2 parts
by weight of the reaction product obtained, 0.1 part of
tetrakis (methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)
propionate~ methane, 0.1 part of 2,6-di-tert-butyl-4-
methyl phenol and 0.1 part of calcium stearate. The mix-
ture was pelletized by using an extruder with an inner
cylinder diameter of 15 mm. The pellets were then molded
into a film by an extruder fitted with a T-die, and the
film was stretched to 5 times its original dimension both
~ - 31 -
1141893
-- 32 --
in the machine and transverse directions at 143C to form
a biaxially oriented film having a thickness of 20 micronsO
The film was subaected to corona discharge treatment, and
its surface resistivity was measuredO The results are
shown in Table ~.
Comparative Exam~le 11
The same copolymer of ethylene and N,M-dimethyl-
aminoethyl meth~crylate as used in Ex~ple 13 was reacted
with ClCH2CO~(CH2)3SC3Na (with an S content of 13~/o by
weig~ht and an Na content of 10.4' by weight) in p-xylene
at 130C for 9 hours to afford a reaction product which
was found to have an S content of 2~78,~ by weight, ~
betaine content of 0O87 milliequivalent/g, an Na content
of 2.6 x 10 4 milliequivalent/g, and a Cl content of 0.02
milliequivalent/g. The product contained the following
units r
t CH2-CH
CH3
---CH2-C ~ - I--
l CH3 CH3
CCOCH2CH2-N-CH2COO(CX2)3S03
. m
(n:m=20:1)
A biaxially oriented ~ilm sub~ected to corona
discharge treatment was prepared in the s~me w-ay ~s in
Example 13 using the reaction product, and its surface
- ~4~893
-- 3~ --
: resistivity.was~e~sured. The results are-shown in
Table 5.
~able 5
~urface resistivity (eh~s
5xample 13 1.0 x 1ol2 to 1ol3
Ccmparative 16
Example 11 1.0 x 10
