Note: Descriptions are shown in the official language in which they were submitted.
~'his invention relates to an aqueous dispersion
for coa~iny. ~lore particu:Lar:ly, -thls invention relates to
an aqueous dispersion forcoating of an ethylenic copolymer
having excellen-t film-Eorming property.
Partially neutralized ethylene/~ ethylenically
unsaturated carboxylic acid copolymer, which contains
carboxylic acid groups in the molecular chain, is known to
be excellent in adhesion to various substrates. It is also
known to coat various substra-tes by using an aqueous disper-
sion of said copo~ymer, as disclosed by United States Patent
3/296,172 and United States Patent 3,677,989. These aqueous
dispersions, however, had the drawback of extremely poor
~ilm-forming property. Namely, when said aqueous dispersion
is coated Oll a substrate to form a dried film through evapo
ration of water, cracks will frequently occur on the film.
Formation of a film even at a considerably high temperature
will fail to produce a good continuous film. Thus, inherent
properties of said copolymer such as good oil resistance,
water resistance, toughness, adhesiveness, heat-seal property,
etc. cannot be exhibited in practical applicàtion.
The present inventors have made extensive studies
to overcome the drawbacks of prior art as mentioned above.
As the result, it has now been found that an aqueous dis-
persion of a partially neutralized ethylene/~,~-ethylenically
unsaturated carbox~vlic acid copolymer is suitable for coating
various substrates, only when said copolymer has a specific
composition distribution.
The present invention provides an aqueous dispersion
for coating comprising a partially neutralized copolymer
comprising from 99 to 75 mol ~, preferably from 98 to 90 mol
- 2 -
3~
of ethylene and from 1 to 2S mol %, preferably from 2 to 10
mol % o~ ethylenically unsaturated carboxylic acid,
of whlch at least 10 % (up to 100 %) is neutralized with
metallic and/or ammonium ions, wherein the improvement
S comprlses using the copolymer having a composition
distribution of acidic units within the range frozn 0.50 to
~.~5, preferably from 0.60 to 0.90 in terms of the ratio
of the reciprocal of the minus first-order moment to the
plus first-order moment of the distribution of the acidic
units. The "acidic units" herein mean comprehensively both
free carboxylic acid groups and carboxylate groups in the
form of neutralized salts.
The reciprocal of the minus first-order moment Cn
and the plus first-order moment C~ of the distribution of
the acidic units are defined by the following formulas,
respectively:
r n
n li~l i i ~ (1)
Cw i~l WiCi (2)
wherein n represents the number of fractions in composition
fractionation of the copolymer; Wi the weight ratio of the
i'th fraction; and Ci the molar ratio of the acidic units
in said fraction, the number n being 7.
The content of the acidic units in said copolymer,
is lim:ited from standpoint of the properties of the
copolymer. If it is less than 1 mol ~, there is no effect
of copolymerization. On the other hand, with content of
higher than 25 mol %, water resistance, and other properties
-- 3
3~
are ex-tremely 1o;~ered. r~ost favorable properties are
ohtained with a content in the range from 2 to 10 mol %.
The copolymer with a ra-tio oE Cn/Cw higher than
0.95 is very n-arrow in distribution of the acidic units
to be highly homogeneous in composition ancl fails to
exhibit excellent film-formin~ property as in the present
invention. On the other hand, with a ratio of Cn/Cw lower
-than 0.50, the distribution of the acidic units is too
broad, and the composition is extremely inhomogeneous to
cause phase separa~ion, whereby no favorable result can be
obtained.
I'he above composition distribution of the acidic
units is determined by fractionation of the copolymer.
The principle of fractionation is based on the difference
in solubility of the two components of the copolymer in
solvents. The polymer to be fractionated is first deposited
on the silica-support in the column, and then eluted succes-
sively by a series of mixed solvents of which solvent power
is successively changed. The partially neutralized copolymer
is first converted with excess amount of acid intG ethylene/
~ ethylenically unsaturated carboxylic acid copolymer.
This copolymer which however is low in thermal stability is
then usually converted wi-th methanol and sulEuric acid into
the corresponding ethylene/~,~-ethylenically unsaturated
carboxylic acid methyl ester copolymer before it is subjected
to fractionation by elution throu~h a column with p-xylene/
2-ethoxyethanol system, according to the same method as
described in U.S. rat~t No. 3,350,372 excep-t that fraction-
ation is performed witn seven fractions by varying the
relative volume of p-xylene/2-ethoxyethanol at ratios of
0:100, 30:70, 50:50, 60:40, 65:3S, 70:30 and 100:0. When
an ethylene/~ ethyleni.cally unsatura-ted carboxylic acid
ester is used as startiny material, the composition distri-
bution of the acidic units can be determined directly by
the above method.
In the accompanying drawings, Fig. 1 shows
integrated composition distribution curves o the copolymers
obtained in Example 1, Comparison example 1, Example 3 and
Comparison example 3, as hereinafter described, said
integrated composition distribution curves being obtained
i -1 .
by plotting ( wj ~ ~ ) versus ci wherein Wi and Wj ~.
pxesent weight ratios of i'th and jlth fractions, respec-
tively and Ci the composition of i'th fraction; Fig. 2 and
Fig. 3 are microphotographs (ma~n:iication x 10) showing
the states of films obtained by drying at 150C the aqueous
dispersions obtained in Example 1 and Comparison example 2
as hereinafter described, respectively.
~xamples of a,~-unsaturated carboxylic acid are
acrylic acid, methacrylic acid, fumaric acid, itaconic acid,
maleic acid, and the like. Furthermoxe, in additi.on to ~ -
said acid components, unsaturated carboxylic acid alkyl ~ -
esters such as methyl acrylate, methyl methacrylate or ;~
vinyl esters such as vinyl acetate may also be contained.
P.n aqueous dispersion of partially neutralized
ethylene/a,~-ethylenically unsaturated carboxylic acid
copolymer can be prepared from ethylene/a,~-ethylenically
unsaturated carboxylic acid copolymer or ethylene/a,~
ethylenically unsaturated carboxylic acid alkyl ester
(Cl - C~ (which is hereinafter reerred to as Ibase
3~
copolymer') accordinc~ -to the methods as disclosed in Belgium
Patent 695,197, United States Patent 3,677,989, United States
Patent 3,296,172 or other known methods for preparation of
neutralized a~ueous dispersions.
For example, according to a preferable method, the
aqueous dispersion of this invention is prepared by adding
the partially neutralized ethylene/~ ethylenically
unsaturated carboxylic acid copolymer into water at a concen-
tration of 10 to 60 wt.~ and heating the mixture at 120~C or
higher under stir~ing. Alternatively, according to another
preferable method, the aqueous dispersion can be prepared
by heating ethylene/~,~-ethylenically unsaturated carboxylic
acid copolymer in an alkaline aqueous solution. In these
methods of preparing self-emulsifying aqueous dispersion,
the copolymer having the specific composition distribution
of the acidic units of the present invention is most prefer-
able. Furthermore these methods are simple to a great
commercial advantage. It is required to neutralize at least
10 % of ~,~-ethylenically unsaturated carboxylic acid in
said aqueous dispersion with metallic or/and~ammonium ions.
Examples of metal]ic lons to be used for neutralization are
those of alkali metals such as sodium, potassium, lithium.
A part of the acid may be neutralized with organic amines,
if desired.
The amount of metallic and/or ammonium ions used
for neutra:lization is limited within the aforesaid range
from standpoint of stability of the aqueous dispersion or
favorable physical properties such as mechanical or oil
resistance properties of the film prepared from said aqueous
dispersion.
2~
Such a base copolymer with a specific composition
distribution of the acidic units can be prepared by utilizing
conventional polymeri~ation technique for production of high
pressure polyethylene. ~he composition distribution of the
acidic units of the copolymer can be varied by varying poly~
merization conditions, the type of the reactor, feeding ratio
of monomers, the reaction temperature, the pressure, the
amount of catalyst, etc. According to a typical procedure,
the base copolymer to be used in the present invention can
be prepared by feeding ethylene and 0.1 to 5 % by weight
(based on the weight of ethylene~ of ~ ethylenically
un~aturated carboxylic acid or an alkyl ester thereof into
a ~lender tubular reactor having a length necessary for
conversion of 5 to 25 % based on the total weight of
ethylene and ~ ethylenically unsaturated carboxylic acid
or the total weight of ethylene and ~,~-ethylenically un~
saturated carboxylic acid alkyl esters having a ratio of
length to diameter from 250:1 to 30,000:1, and then
pol~merizing the monomers at a temperature of 150 to 300C,
under a pres~ure of 1,500 to 3,000 kg/cm2 in the presence
of oxygen or a free radical catalyst. And if necessary,
as described in United States Patent 3,334,081, monomers
are fed through the feeding points put along the tubular
reactor. In the present invention, however, the method
for preparation of the base copolymer is not limited in
any way but various procedures known in the art are
available, for example, preparation method with a multi-
stage autoclave as described by British Patent 965,838
or other methods for preparation of high pressure poly-
ethylene polymers.
7 --
~;23~
The base copolymer should preferably has a melt
index of from 1 to 100 g/10 minutes in case of ethylene/~
ethylenically unsaturated carboxylic acid and of from 5 to
300 g/10 minutes in case of ethylene/~,~-ethylenically
unsaturated carboxylic acid alkyl ester.
The thus obtained aqueous dispersion of partially
neutralized ethylene/~ ethylenically unsaturated carboxylic
acid copolymer having a specific composition distribution of
the acidic units exhibits excellent film-forming property.
Namely, when said aqueous dispersion is coated on a substrate
and dried to form a film on the substrate, there can be
formed a film with no crack at a relatively low drying
temperature. Such an effect is entirely unexpected from
the state of prior art. Conventionally, as described in
United States Patent No. 3,677,989, it has been accepted
that a preferred copolymer for an aqueous dispersion is
one in which each polymer macromolecule must contain
substantially the same proportions of polymerized comonor,ler
as the other macromolecules, (i.e., the value of Cn/Cw as
defined in the present invention is substantially equal to
1.0). In the light of such a generally accepted recognition,
it is entirely surprising that the copolymer having a
specific broad composition distribution of the acidic units
of the present invention has such an excellent film-forming
property.
The aqueous dispersion of ethylenic copolymer hav-
ing excellent film-forming property is particularly suitable
for coating of various substra-tes. Examples of substrates
are metals such as aluminum, chromium, iron, etc.; inorganic
materials such as glasses, ceramics, clays, calcium sulfate,
-- 8 --
~23~
calcium carbonate, etc.; thermosetting polymers such as
phenol resins, melamine resins~ epoxy resins, etc.;
thermoplastic polymers such as styrene resins, polyester,
polyurethane, polyacetal, polyamide, polyethylene, poly-
propylene, etc.; proteinous materials such as leather, fur,gelatin, etc.; natural fibers such as cotton, silk, wool,
etc.; cellulosic materials such as paper, wood, cellophanes,
etc.; and natural or synthetic rubbers. These substrates
may be shaped in films, sheets, bottles, powders, granules,
fibers, ropes, fabrics, unwoven fabrics, porous or non-
porous shapes, etc.
Particularly suitable applications are coatings of
papers, cellulosic material (e.g. ethyl cellulose, cellulose
acetate, cellulose propionate, cellulose acetate butyrate,
cellulose nitrate, etc.) or aluminum foils or cans and
coatings of films, sheets, bottles or tubes of synthetic
resins such as polyamide, polyvinylalcohol, polyvinyl
chloride, polystyrene, polyvinyliclene chloride, polypro-
pylene, polyethylene, polyester, etc. By such coatings,
these substrates are endowed with oil resistance, heat seal
property and adhesiveness to other substrates. In application
of such coatings, adhesives such as of isocyanate type, imine
type, chlorinated polyolefin type, organic titanate type, etc.
may also be used, if desired, for increasing adhesion of
coating onto substrates. Coating of glass fibers, talc or
calcium carbonate will impart sheafing property to these
materials. Further, when the thus coated materials are used
as fillers in synthetic polymers, adhesion pxoperty of filler/
polymer interface can be improved to give composite materials
having excellent properties. If necessary, organic silane
coupling agent~ may also be used in combination. Typical
examples of organic silane coupling agents are silanes
containing two or three readily hydrolyzable yroups such
as -OOR or -OR (wherein R represents an alkyl or a cyclo-
alkyl having 1 to 8 carbon atoms), including commerciallyavailable organic silanes such as chloropropyl trimethoxy
silane, ~-aminopropyl triethoxy silane, ~-methacryloxypropyl
trimethoxy silane, vinyl trimethoxy silane, and so on.
Adhesiveness is also imparted by coating natural or synthe-
tic fibers. Coating of a glass bottle or a glass plate willprevent glass pieces from scattering when it is bursted.
The uses of the aqueous dispersion is not limited to those
as mentioned above.
The present invention is described in further detail
by referring to the following Examples, which are set forth
for not limiting but only illustrative purpose.
Example 1
Into a tubular reactor with diameter of 4.8 mm and
length of 20 m were fed 13 kg/hour of ethylene, 0~28 kg~hour
of methyl methacrylate and 20 ppm ~based on ethylene) o~
oxygen as catalyst. Polymerization was carried out at a
temperature of 220C under pressure of 2500 kg/cm2 to
conversion of 12~ based on the total weight of ethylene and
methyl methacrylate. The resultant ethylene/methyl meth-
acrylate copolymer contained 5.7 mol % o~ me~l m~th~oryla~and had a melt index of 90 g/10 min. (ASTM-D-1238)~
Composition fractionation of this copolymer by column
elution method gives the value Cn/Cw of 0.61. The curve
of integrated composition distribution of the acidic units
of this copolymer is shown in ~ig. 1.
- 10 -
3~L
Fifty grams o~ this copolymer, 90 g of benzene,
20 g of methanol and 12.8 g of caustlc soda were dissolved
in a pressure glass tube at 120C to carry out the reaction
for 2 hours. After completion of the reaction, the tempera-
ture of the reactlon mixture was lowered to 80C and 2B.5 g
of 5G wt. % of sulfuric acid was added to the mixture for
removal of sodium. The reaction product was separated by
precipitation. The resultant cake was washed with water
and dried after recovery of the solvent to obtain partially
neutralized ethylene/methacrylic acid copolymer in which
36 % of methacrylic acid was neutralized with sodium ions.
Forty grams of this copolymer and 120 g of water were
introduced to a pressure vessel and stirred at 140C for 3
hours to obtain an aqueous dispersion. Stirring was
performed by means of propeller type stirring blade at
1000 r.p~m. The resultant aqueous dispersion had a solid
content of 24 %, viscosity of 25 c.p. measured by a Brook-
field viscometer at 25C and average diameter of 0.3 micron.
Example 2
Example 1 was repeated except that 13.0 kg/hour
of ethylene, 0.23 kg/hour of methyl methacrylate were used
and conversion ~ased on the total weight of ethylene and
methyl methacrylate was 10 %, to prepare ethylene/methyl
methacrylate copolymer containing 5.8 mol % of methyl
methacrylate with Cn/Cw of 0.85 and a melt index of 85 g/
10 min. Then, according to the same method as in Example 1
except that 12.9 g of caustic soda and 28.5 g of 50 wt. %
sulfuric acid were used, an aqueous dispersion in which 32 %
- of methacrylic acid was neutralized with sodium ions with
solid components of 24 %, viscosity of 35 c.p. and average
-- 11 --
L
par-ticle di~meter oE 0.3 microns was obtained.
Example 3
According to the same procedure as described in
E~ample 1 except that 13.0 kg/hour of ethylene and 0.19 kg/
hour of methyl methacr~late were used and the conversion
based on the total weight of ethylene and methyl methacrylate
was 8 %, there was obtained ethylene/methacrylate copolymer
containing 5.8 mol % of methyl methacrylate, Cn/Cw = 0.92,
and melt index of ~0 g/10 min. Then, similarly as described
in Example 1, using 12.9 g of caustic soda added and 28.6 g
of 50 wt. % sulfuric acid, there was obtained an aqueous
dispersion in which 29 % of methacrylic acid was neutralized
with sodium ions with solid content of 22 %, viscosity of
40 c.p. and average particle diameter of 0.3 micron.
Example 4
Example 1 was repeated except that 13.0 kg/hour of
ethylene, 0.4 kg/hour of methyl methacrylate were used and
the conversion based on the total weight of ethylene and
methyl methacrylate was 10 ~ to obtain an ethylene/methyl
methacrylate copolymer containing 9.7 mol % of methyl
methacrylate with Cn/Cw of 0.85 and melt index of 130 g/10
min. Then, according to the same procedure as in Example 1
except that the amount of caustic soda added was 15.0 g and
that of 50 wt. % sulfuric acid 3?~8 g, there was prepared
ethylene/methacrylic acid partially neutralized copolymer
in which 32 % of methacrylic acid was neutralized with
sodium ions. Then,according to the same method as in
Ex.ample 1 an aqueous dispersion was obtained. The resultant
aqueous dispersion had a solid content of 24 %, viscosity o-f
25 c.p. and average particle diameter of 0.3 micron.
~~9~3~L
Example S
Using 50 g of ethylene/methyl methacrylate
copolymer obtained in ~xample 1, 10.7 g of caustic soda and
26.3 g of 50 wt. % sulfuric acid, ethylene/methacrylic acid
copolymer was prepared. Then, an aqueous dispersion of this
copolymer was prepared according to the same method as
disclosed by U.S. Patent No. 3,296,172. This aqueous
dispersion, in which 30 % of methacrylic acid was neutralized
with sodium ions, had a solid content of 25 %, a visicosity
of 30 c.p. and an average particle diameter of 0.3 micron.
The aqueous dispersion contained 4.8 % ~based on solid
components) of sodium oleate.
Example 6
Using the ethylene/methacrylic acid copolymer
obtained in Example 5, an aqueous dispersion was obtained
in the same manner as in Example 5 by neutralizing 10 % of
methacrylic acid with sodium ions and residual 90 % with
ammonium ions. This dispersion had a solid content of 26 %,
viscosity of 20 c.p. and average particle diameter of 0.3
microns.
Comparison example 1
In a continuous complete mixing type autoclave of
15 liter inner volume with a ra~io of depth/diameter of 3
were charged 800 kg/hour of ethylene, 14 kg/hour of methyl
methacrylate and 60 ppm (based on ethylene, calculated as
oxygen) of lauryl peroxide as catalyst. Polymerization was
carried out under pressure of 2000 kg/cm2 at a temperature
of 200C to a conversion of 10 ~ based on the total weight
of ethylene and methyl methacrylate. The resultant
ethylene/methyl methacrylate contained 5.7 mol % of methyl
~ 13 -
~3~3~.
methacrylate wi.-th melt index of 85 g/10 min. and Cn/Cw = 0.97.
The curve o~ ~he integrated composition distribution of the
acidic units o~ thls copolymer is shown in Figo 1~ Uslng thls
copolymer, partially neutralized ethylene/methacrylic acid
copolymer in which 33 ~ o~ methacrylic acid was neutralized
with sodium ions was prepared in the same manner as in
Example 1.
Then, according to a procedure similar to Example
1, an aqueous dispersion was prepared from this copolymer.
But the resultant dispersion was poor in stability and
separation occurred a~ter standing for overnight.
Comparison example 2
The ethylene/methyl methacrylate copolymer prepared
in Comparison example 1 was converted to ethylene/methacrylic
acid copolymer in the same manner as in Example 5. Then,
similar].y as in Example 5l an aqueous dispersion with solid
content of 24 %, viscosity of 30 c.p. and average particle
diameter of 0.3 micron was prepared. In this dispersion,
30 % of methacrylic acid was neut:ralized with sodium ions
and 4~8 % (based on solid welght) of sodium oleate was
contained.
Comparison example 3
According to the same procedure as described in
Example 1 except that 13.0 kg/hour of ethylene and 0.68
kg/hour of methyl methacrylate were used and the conversion
based on the total weight of ethylene and methyl methacrylate
was 28 %, there was prepared an ethylene/methyl methacrylate
copolymer containing 5.8 mol ~ of ~ethyl methacrylate with
Cn/Cw = 0.45 and melt index of 62 g/10 min. Then, ethylene/
methacrylic acid copolymer was prepared in the same manner
3~
as in E~ample 5 except that the amount of caustic soda added
was 10.~ g and that of 50 wt. ~ sulfuric acid 28.4 g. By
using this copol~ner an aqueous dispersion in which 30 %
of methacrylic acid was neutralized with sodium ions having
solid content of 25 %, viscosity of 50 c.p. and average
particle diameter of 0.3 micron was obtained according to
the same method as in Example 5.
Comparison example 4
Using the ethylene/methyl methacrylic acid
copolymer obtained in Comparison example 2, there was
prepared an aqueous dispersion in which 10 % of methacrylic
acid was neutralized with sodium ions and residual 90 % with
ammonium ions according to the same method as in Example 6.
This dispersion had a solid content of ~3 %, viscosity of
25 c.p. and average particle diameter of 0.4 micron.
Comparison example 5
By the method similar to Comparison example 1, an
ethylene~methyl methacrylate copolymer containing 9.8 mol %
of methyl methacrylate with Cn/Cw = 0.98 and melt index of
110 g/10 min. was prepared. Then, according`to the same
procedure as in Comparison example 1 except that the amount
of caustic soda added was 15.1 g and that of 50 wt. % sul-
furic acid 32.5 g, there was obtained a partially neutralized
ethylene/methacrylic acid copolymer in which 35 % of methacry-
lic acid was neutralized with sodium ions Using this
copolymer, according to the same method as in Example 4, an
aqweous dispersion was obtained. This dispersion had a solid
content of 24 %, viscosity of 40 c.p. and average par~icle
diameter of 0.4 micron.
- 15 -
Z3~
Example 7
Each of the aqueous dispersions prepared in
Examples l, 2, 3 and 6 and Comparison examples 2 through 4
was coated uniformly on a glass plate in thickness of dried
film of 7 to 10 microns. Films were formed by varying the
temperature and the state of the films formed were observed.
The results are shown in Table l. The films formed at 150C
of Example l and Comparison example 2 were photographed to
give the results as shown in microphotographs l and 2.
(magnification x 1-0)
As apparently seen from Table 1, no continuous
film can be formed at a considerably high temperature for
Cn/Cw > 0.95. On the other hand, for Cn/Cw < 0.5, continuous
film can be formed at 60C but the film is turbid. Within
the range 0.5 _ Cn/Cw _ 0.95, tra.nsparent continuous film
can be formed at 40C to 80C.
- 16 -
33~
~, 0 ~ 0
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o ,c~ r~;' U Q E~
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~C~ O O Orl h ::~ rJ O rl h
E~ -1 ~ 3 U ~ 3 U
h C~ ,~ .ra
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h ~1 O O O~J h ~ r~ O ~rl h
11~ ~ t~ 3 U O ~ 3 U
E~ 0 ~:5 0
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~ O O Orl ~ ,J rl O rl (I
U ,-J ~ ~ ~)3 U 1~ 3 U ~ O
r~ u~ rl
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11) co O Q O rl S-l ~ rl O r~ O
O ~ 3 U O ~ ~J)3 C~
~ u~ a 0 Ei -l
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~ O ~ u ~ u ~ a ~ u ,1 ~ o
h o O O ~ r~ ~ ~h ~ O ~) 1~ r~ O
o ~D O O ''I h ~-1 h_~ ~J 0 ~I h
~3 t)' b' 3 U 3 u~) 'H t~ 3 u X ~:
a)
U~ 0 0 0 0 U~ U~ ~ 0
C~ ~ XX X ~ ~ X ~
r~ O ~ ~ t)rC O~ U ~ U~ 1~~ O ~ ~ O
o
,~ ~ 3 U 3 t~ 3 U 3 h 3 ~ 3J ~ ~3 ~-~ 3~r~
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t~ 4
O rJ ~ ~ O OO O O O ~ 3
r-l d r~ ~ ~ ~ ~,-1 o ,1 0 S: O
-- ,~ r~ O X '~
_, _ r~ U ~
h ~ ~ ~d N
(~ h rl
a) a) N R ~-1
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u ~ ~ a
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s, o . . . . . . . 0 a
U ~ i u~
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3 , i L~ 3 ~ rC
Iw ~9 o~ ~ ~ ~r ~ ~
1~ o o o o o o o
Y7 0 ~~ ~ o ~r
0 0
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~e o x x o ~
3~
Example 8
The aqueous dispersion obtained in Example 1 was
double coated on an art paper base stock 75 g/m2 in total
amount of 10 g/m2 and dried at 150C. A uniform film was
found to be formed on the paper. When this coating was
heat sealed by means of Centinel Heat Sealer under conditions
of 120C, 2 kg/cm2, one second, the peel-off strength was
found to be 0.45 kg/15 mm. Peel-off test was performed by
T~type peeling at 300 mm/minute. Fuxthermore, when penetra-
tion of mineral oil was tested at room temperature, no
penetration of oil was observed after 30 days. On the other
hand, when similar coating is applied by use of the aqueous
dispersion of Comparison example 2, a film with many cracks
was formed and mineral oil was readily penetrated there-
through.
Example 9
The aqueous dlspersion obtained in Example l was
coated on an aluminum foil in amount of 10 g/cm2 and dried
at 120C whereby a transparent and uniform continuous film
was found to be formed on the aluminum foil.` Peel-off
strength after heat sealing by means of Centinel Heat Sealer
under conditions of 120C, 2 kg/cm2 and one second 0.80 kg/
15 mm by the same test method as in Example 3.
For comparison, the aqueous dispersion obtained
in Comparison example 2 was coated in 10 g/cm2 on aluminum ~-
foil and dried at 120C, whereby only a film with many
cracks was formed.
Example 10
The aqueous dispersion obtained in Example 4 was
coated on an aluminum foil in amount of 10 g/cm2 and dried
18 -
at 120C. A -transparent and uniform continuous film was
found -to be formed on the aluminum foil. Peel-off strength
of this coa-tiny was measured by T-type peel-off at 300 mm/
minute after heat sealing by means of Centinel ~eat Sealer
under condi-tions of 120C, 2 kg/cm2 and one second to be
1.13 ky/15 m~.
For comparlsonl the aqueous dispersion obtained
in Comparison example 5 was used to carry out the same test
to obtain a peel off strength of 0.53 kg/15 mm.
Example 11
The aqueous dispersion prepared in Example 1 was
coated on a nylon film of 15 ~ in thickness on which an
adhesive had previously been applied. As an adhesive,
there was employed an isocyanate type adhesive comprising
a 9:1 mixture of Takelac A-371 and Takenate A-3 (trade
marks: Takeda Chemical Industries, Ltd., Japan) in an amount
of 0.3 g/m . Said aqueous dispersion was coated on the
adhesive in an amount Of 5 g/m2 and dried at 120C. The
coated surfaces were subjected to heat sealing face to face
by means of Centinel ~eat Sealer at 120C under a pressure
of 2 kg/cm2 for one second. The peel-ofE strength was
measured to be 0.45 kg/15 mm by T-type peeling test at the
rate of 300 mm/minute.
For comparative purpose, similar test was conducted
by use of the aqueous dispersion obtained in Comparison
example 3, whereby a turbid film was formed with peel-off
strength of 0.28 kg/15 mm.
~ample 12
The aqueous dispersion obtained in Example 1
(100 g) was diluted with 890 g of water containing 0.025
- 19 -
of a nonionic surfactant (Emulgen 985, trade mark:
Kao-Atlas ~o., Japan) under stirring, followed by further
addition of 10 g of y-aminopropyl triethoxy silane under
stirring. The resultant composition for treatment of
fibers exhibited no formation of precipitate but remained
as a good dispersion even after standing at room temperature
for one month. Then, into the above composition were dipped
glass fibers subjected to sizing with water. The treated
glass fibers, after drying at 130C in a hot air oven, were
cut into pieces with 6 mm length. Thirty parts of the cut
glass fibers and 70 parts of a high density polyethylene
(Suntec J 240, trade mark: Asahi Kasei ~ogyo Kabushiki
Kaisha, Japan) were extruded at 230C through a uniaxial
extruder. IJsing the thus formed pellets for molding, test
pieces were injection molded for measurement of physical
properties. The results are shown in Table 2.
For comparative purpose, a composition for treat-
ment of fibers was prepared similarly by use of the aqueous
dispersion prepared in Comparison example 2. But a great
amount of precipitates were observed to be formed simulta~
neously with addition of ~-aminopropyl triethoxy silane.
Accordingly, by increasing the amount of the nonionic
surfactant to 4 % based on the weight of said copolymer,
under otherwise the same conditions in Example 12, a
composition was prepared from the aforesaid dispersionO
Th~ thus prepared composition was less in amount of precipi~
tates formed as compared with that with smaller amount of
the surfac'cant. Treatment of glass fibers was conducted
using this composition by the same method as in Example 12
and the treated glass fibers were blended with high-density
- 20 -
23:~
polyethylene to give the results as shown in Table 2.
Table 2
Heat
Izod dis-
impact tortion
Tensile Flexural Flexural strength temper-
Co--C /- strength strength modulus (notched; ature
polymer n Cw (kg/cm2) (kg/cm2) (kg/cm2) kg-cm/cm) (C)
Example
1 0.61 650 900 43,00013.5 115
Com-
parison
example
2 0.97 480 610 38,000 8.0 108
Example 13
To 2.5 liters of water was added 500 g of quick
lime to prepare a slurry of slated lime and carbon dioxide
gas was injected thereinto until pH of the slurry was 7 to
prepare precipitated calcium carbonate. Then, the tempera-
ture of the product was raised to 80C and 120 g of the
aqueous dispersion obtained in Example 5 was added thereto,
followed by filtration and drying to obtain coated precipi-
tated calcium carbonate. The coated precipitated calcium
carbonate was compounded with ethylene/propylene/ethylidene
norbornene copolymer (EPDM) (EPT 3045~ Mitsui Polychemical
Co., Japan) according to the formulations set forth below
and the compound was subjected to press vulcanization at
160QC for 30 minutes.
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3~
E M formuL_t1on
Mitsui EPT 3045 - 100 parts
~inc oxide 5
stearic acid
tetramethylthiuram monosulfide 1.5
2-mercapto benzothiazole 0.5
sulfur 1.5
calcium carbonate 100
Similarly, the above procedure was repeated by
aclding 0.3 g of y~aminopropyl triethoxy silane together
with the aqueous dispersion and also, for comparative
purpose, precipitated calcium carbonate without the above
treatment was formulated in the same manner as described
above. Measurement of physical properties of these
formulations were carried out according to the method o~
JIS K~6301 to obtain the results as shown in Table 3. ~-
Table 3
_ . .
Coating materia:L ~ensi]e strength(kg/cm2) Elongation(~)
.... ~
A~ueous dispersion
of the invention 69 S10
Aqueous dispersion
of the 'nvention 98 630
Organic silane
Control 34 300
Example 14
A fabric made of nylon 66 fibers was immersed in
the aqueous dispersion obtained in Example 1 to uniformly
adhere said dispersion to the fabric. ~fter preliminary
dryiny at 80C, the fabric was further heated at 200C for
- 22 -
3~
3 minutes. The thus treated nylon fabric was adhered to
ethylene/vinyl acetate copolymer (EVA)(Evaflex 460, trade
mark, Mitsui Polychemical Co. 9 Japan) with heating at 200C
under pressure of 4.2 kg/cm2 for 25 seconds. Peel-off test
was conducted by T-type peel-off method at the rate of
50 mm/minute using a tension tester. The result is shown
ln Table 4. For comparison, the same test was conducted
for nylon 66 fabric which has not been treated with the
aqueous dispersion to give the result as shown in the same
Table.
Example 15
Example 14 was repeated except that cotton fabric
was used in place of nylon 66 fabric. The results are also
shown in Table 4.
Table 4
Peel-off
Fabric _ Treatment strength(kg/cm)
Example 14 Nylon 66 treated 1.5
" not treated 0.4
Example 15 Cottontreated 1.7
" not treated 0
As apparently seen from the above Examples, the
aqueous dispersion of ethylenic copolymer having specific
composition distribution is excellent in film-forming
property and very useful for coating of various substrates.
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