Note: Descriptions are shown in the official language in which they were submitted.
CA 02041792 2002-07-12
1
MICROCAPSULES
The present invention relates to microcapsules
which are obtained by polymerizing
A) 30-100% by weight of one or more C1-C24-
alkyl esters of acrylic or methacrylic acid (monomers I),
B) 0-70% by weight of a bi- or polyfunctional
monomer (monomer II) which is soluble in a so1-vent which is
insoluble or only sparingly soluble in water, and
C) 0-40% by weight of other monomers (monomers
III) , wherein the solvent with or without the monomers and
a free radical initiator, form a disperse phase of a stable
oil-in-water emulsion and the polymerization is initiated
and controlled stepwise through the thermal decomposition
of the free radical initiator by ranging the temperature.
The present invention also relate:; to a process
for preparing microcapsules, to the use of color former
microcapsules for praducing pressure-sensitive recording
materials and to these recording materials.
EP-A-026 914, EP-A-133 295 and EP-A-218 887
disclose microcapsules which are based on melamine
formaldehyde, resins and are recommended for pressure
sensitive recording materials.
A further method for preparing mic:rocapsules is
that of in situ polymerization, The microcapsules are
produced, for example by the method described in
EP-A-198 089, by first preparing a solution of monomers
such as acrylic esters, a water-insoluble solvent, a free
radical initiator, a polymer and the substance to be
encapsulated and then converting this solution into a
stable oil-in-water emulsion. Then the pohymerization of
the monomers is initiated by raising the temperature, and
the resulting polymers form the walls of capsules which
tightly enclose the remaining organic solution of the
substance which is to be encapsulated.
CA 02041792 2002-07-12
la
The substances mentioned for microencapsulation
in this context are dyes, detergents, printing inks,
perfumes, adhesives, medicines, agrochemicals, ferti-
lizers, fats, oils, nutrients, enzymes, liquid crystals,
paints, rustproofing agents, recording materials,
CA 02041792 2002-07-12
2
catalysts, chemical reactants and magnetic substances.
The microcapsules of the present invention are
prepared from 30 to 100 ~S by weight, preferably 30-95 ~
by weight, of one or more C1-C24-alkyl esters of acrylic
and/or methacrylic acid as monomers I.
In addition, the microcapsules of the present
invention may also be formed from up to~ 70 $ by weight,
preferably 5-40 ~ by weight, of a bi- or polyfunctional
monomer which is soluble in a water-insoluble or only
1G sparingly water-soluble solvent as monomer II and from up
to 40 ~ by weight, preferably up to 30 ~ by weight, of
other monomers III.
Suitable monomers I are C~-C24-alkyl esters of
acrylic and/or methacrylic acid. Particularly preferred
15~ monomers I are methyl, ethyl, n-propyl, n-butyl and
2-ethylhexyl acrylates and methacrylates. Preference is
given to isopropyl, isobutyl, sec-buty:L and tert-butyl
acrylates and methacrylates. But it is also possible to
use n-pentyl, n-hexyl, n-heptyl, n-octyl and lauryl
20 acrylates and methacrylates.
Suitable additional monomers II are bi- or
polyfunctional monomers which are soluble in water-
insoluble or only sparingly water-soluble solvents,
chiefly divinyl and polyvinyl monomers which bring about
25 a crosslinking of the capsule walls during the polymeriz-
ation.
Preferred divinyl monomers are ethanediol diacry-
late, divinylbenzene, ethylene glycol dimethacrylate,
1,3-butylene glycol dimethacrylate, methallylmethacryl-
30 amide and allyl methacrylate. Particular preference is
given to propanediol, butanediol, pentanediol and hexane-
diol diacrylates or methacrylates.
Preferred polyvinyl monomers are trimethylol
propane triacrylate and methacrylate, pentaerythritol
35 triallyl ether and pentaerythritol tetraacrylate.
The crosslinking may also be effected via groups
capable of addition or condensation, 'with or without
further at least bifunctional such groups, in which case
the crosslinking reaction is carried out after the
~,_~ ~ ~~;~
- 3 - O.Z. 0050/41614
polymerization.
Monomers having such groups are, for example
glycidyl acrylate and methacrylate and in particular
vinyl compounds which contain amino, acetylacetone, epoxy
or methylol groups.
The functional groups of these monomers may be
crosslinked for example via bi- or polyfunctional
epoxies, amines and alcohols, preferably via urea- and
melamine-formaldehyde precondensates.
Particularly good results with subsequent cross-
linking are obtained on using acetoacetoxy ethyl meth-
acrylate as functional monomer and formaldehyde or
glutaraldehyde as crosslinking component.
Suitable monomers III are any other monomers,
preferably styrene, a-methylstyrene, ,e-methylstyrene,
butadiene, isoprene, vinyl acetate, vinyl propionate and
vinylpyridine.
Particularly preferred monomers III are acrylo
nitrile, methacrylamide, acrylic acid, methacrylic acid,
itaconic acid, maleic acid, malsaic anhydride, N-vinyl
pyrrolidone, 2-hydroxyethyl methacrylate and acrylamido-
2-methylpropanesulfonic acid.
It is also possible to use N-methylolacrylamide,
N-methylolmethacrylamide,dimethy:Laminoethyl methacrylate
and diethylaminoethyl methacxylat:~.
The microcapsules of the present invention are
prepared by polymerization of monomers I, II and III,
said polym~rization being initiated and controlled by
raising the temperature to a level where the thermal
decomposition of the free radical initiator takes place.
Suitable free radical initiators for the polymer
ization reaction are the customary peroxo and azo com
pounds, advantageously in amounts of from 0.2 to 5 $ by
weight, based on the weight of the monomers.
Preferred free radical initiators are tart-butyl
peroxyneodecanoate, tart-amyl peroxypivalate, dilauryl
peroxide, tart-amyl peroxy-2-ethylhexanoate, 2,2'-azobis-
(2,4-dimethyl)valeronitrile, 2,2°-azobis(2-methylbutyro-
nitrile), dibenzoyl peroxide, text-butyl per-2-ethyl-
~~_~~'~~,
- 4 - O.Z. 0050/41614
hexanoate, di-tart-butyl peroxide, tart-butyl hydroper-
oxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and
cumene hydroperoxide.
Particularly preferred free radical initiators
are di(3,5,5-trimethylhexanoyl) peroxide,4,4'-azobisiso
butyronitrile, tart-butyl perpivalate and dimethyl
2,2-azobisisobutyrate. These have a half-life of 10 hours
within the temperature range from 30 to 100°C.
The monomers and the free radical initiator can
be dissolved in a water-insoluble or only sparingly
water-soluble solvent which forms the disperse phase of
a stable oil-in-water emulsion. It is however also
possible first to disperse the solvent and add the
monomers and the free radical initiator to the disper
sion. A further possibility is to place the solvent and
monomers in dispersion and to add dust the free radical
initiator subsequently. The solvent may of course contain
other substances, such as color formers.
Suitable water-insoluble or only sparingly water
soluble solvents are natural oils, synthetic oils and
solvents having boiling points within the range from
80 to 350°C, preferably from 150 to 350°C. The oil con
tent of the oil-in-water emulsion is preferably 20-60 $
by weight.
Preferred water-insolub;Le or only sparingly
water-soluble solvents are gasolines, mineral oils,
paraffins, chloroparaffins, fluorocarbons, groundnut oil,
soybean oil, chlorinated biphenyls, tributyl phosphate,
dibutyl maleate, o-dichlorobenzene, benzyl alcohol,
diisopropylenenaphthalene and 1-phenyl-1-xylylethane.
Particularly high solubilities of the substances
such as color formats contained in the water-insoluble or
only sparingly water-soluble solvents are obtained in
those solvents whose boiling points are within the range
from 150 to 350°C, for example in dibutyl phthalate,
diisoheptyl phthalate, dioctyl phthalate, alkylnaphtha-
lenes and partially hydrogenated terphenyls and in
particular in diisopropylnaphthalene, dodecylbenzene and
mixtures thereof.
~=~~""~
!~w
- 5 - O.Z. 0050/41614
The substances contained in the capsules are in
particular those mentioned on page 2, with color formers
being preferred.
Suitable color formers for encapsulation are for
example colorless or only slightly colored compounds
which are converted into dyes in the presence of acids,
as is true for example of numerous phthalides, which as
the lactone ring opens form colored open-chain acids.
Preferred color formers are 3,3-bis(p-dimethyl
aminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3-(1,2
dimethylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)
3-(2-phenylindol-3-yl)phthalide, Rhodamine-B-anilino
lactam,3-dimethylamino-7-methoxyfluoran,p-nitrobenzoyl
leuco methylene blue, 3-methylspirodinaphthopyran and
3-propylspirodibenzopyran.
Particular preference is given to 3,3-bis(p-
dimethylaminophenyl)-6-dimethylaminophthalide and
N-benzoyl-leuco methylene blue and mixtures thereof.
In general, the color formers are used in amounts
of from 1 to 10 ~ by weight, prei:erably from 2 to 8 ~ by
weight, based on the oil phase of the emulsion.
Suitable acidic color developers are acid clay,
attapulgite, aluminum silicate, benzoic acid, chloro-
benzoic acid, toluylic acid, salicylic acid and 4-tert-
butylsalicylic acid and also in particular kaolin and
alkyl-substituted phenols.
The microcapsules according to the invention can
be prepared in a conventional manner, for example by the
methods described in EP-A-198 089.
In general, the polymerization is carried out at
from 20 to 100°C, preferably at from 40 to 80°C.
Advantageously, the polymerization is carried out
under atmospheric pressure, but it may also be carried
out under a reduced or slightly superatmospheric pres
sure, say within the range from 0.5 to 5 bar.
The reaction time is normally from Z to 10,
usually from 2 to 7, hours.
As a general procedure a mixture of water,
protective colloids, ionic emulsifiers, water-insoluble
~Q~° ~.7~~
- s - o.~. 005o/41s14
or only sparingly water-soluble solvents, other sub-
stances contained therein in dissolved form, free radical
initiators and monomers, added simultaneously or succes-
sively, is dispersed and heated with intensive stirring
to the decomposition temperature of the free radical
initiators.
The polymerization can be controlled via the
temperature and the amount of free radical initiator.
After the reaction temperature has been reached,
the polymerization is advantageously continued for a
period of about 2 to 6 hours in order to reduce the
residual monomer contents.
Preferred emulsifiers are water-soluble polymers,
since they reduce the surface tension of the water from
the maximum of 73 mN/m to 45-70 mN/m and thus ensure the
formation of continuous capsule walls, giving microcap-
sules having particle sizes of from 1 to 30 ~.m, prefer-
ably from 3 to 12 gym.
Particularly preferred protective colloids are
cellulose derivatives such as hydroxyethylcellulose,
carboxymethylcellulose and methylcellulose, polyvinyl
pyrrolidone and copolymers of vinylpyrrolidone.
Preference is given to gelatine, gum arabic,
xanthan, sodium alginate, casein, polyvinyl alcohol and
partially hydrolyzed polyvinyl acetates. .
In general, the protective colloids are used in
amounts of from 0.1 to 10 $ by weight, preferably from
0.5 to 5 $ by weight, based on the water phase of the
emulsion.
To improve the stability of the emulsions, ionic
emulsifiers may be added. It is particularly important to
use ionic emulsifiers if the microcapsule content of the
dispersion is large, since without an additional ionic
stabilizer the microcapsules may agglomerate. These
agglomerates, if from 1 to 3 ~m in diameter, would reduce
the yield of usable microcapsules or if greater than
about 10 ~m would increase the rub sensitivity.
Suitable ionic emulsifiers are in particular
polymethacrylic acid, the polymers of sulfoethyl acrylate
- '1 - O.Z. 0050/41614
znd methacrylate, of sulfopropyl acrylate and meth-
acrylate, of N-(sulfoethyl)maleimide, of 2-acrylamido-2-
alkanesulfonic acids, of styrenesulfonic acid or of
vinylsulfonic acid.
Preferred ionic emulsifiers are naphthalene-
sulfonic acid and naphthalenesulfonic acid/formaldehyde
condensates and in particular polyacrylic acids and
phenolsulfonic acid/formaldehyde condensates.
The ionic emulsifiers are in general used in
amounts of from 0.1 to 10 ~ by weight, based on the water
phase of the emulsion.
Preferably, the polymerization conditions are
selected in a conventional manner which serves to ensure
that the microcapsules have diameters of from 1 to 35 ,um,
in particular from 3 to 15 gym.
The viscosities of the cagsule dispersions are
measured in seconds as efflux times of 100 ml of the
dispersion from the 4 mm Ford cup in accordance with
German Standard Specification DIN 53 211.
The dispersions of the microcapsules of the
present invention have solids contents of preferably
20-60 $ by weight.
The color former microca~psules of the present
invention are used for producing pressure-sensitive
recording materials.
These materials are primarily copy papers which
are impregnated with the color developer and coated with
a dispersion of microcapsules. The pressure of the
writing implement causes the microcapsules to burst open,
so that the color formers, or dye-forming components,
.corm a dye on development.
The microcapsule dispersions obtainable according
to the present invention can be used directly for paper
coating or they can be dried, for example spray dried,
and redispersed before use.
EXAMPLES
Preparation of color former microcapsules
EXAMPLE 1
A mixture of
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1280 g of water
20 g of polyvinylpyrrolidone of R 90
15 g of phenolsulfonic acid/formaldehyde condensate
522 g of diisopropylnaphthalene
522 g of dodecylbenzene
48 g of a mixture of 36 g of 3,3-bis(p-dimethylamino-
phenyl)-6-dimethylaminophthalide and 12
g of
N-benzoylleuco methylene blue
168 g of methyl methacrylate
19 g of butanediol diacrylate
1.4 g of azobisisobutyronitrile
2 g of dimethyl 2,2-azobisisobutyrate
was dispersed
at room
temperature
for
minutes.
It was
then
heated,
with
continuing
dispersing,
to 60C
and
15 maintained
at that
temperature
for
1 1/2
hours.
This
is
followed
by heating
at 65C,
further
polymerization
for
4 hours
and
cooling.
The solids content of the dispersion obtained
was
49.1 by weight, and efflux time from the Ford
$ cup was
20 101 seconds.
The average particle size of the microcapsules
is
5.6 ~m with a practical variation in size from
3 to 7 Vim.
EXAMPLE 2
This dispersion was prepared in the manner
of
Example
1 from
the
following
componentss
1287 g of water
20 g of polyvinylpyrrolidone of K 90
18 g of phenolsulfonic acid/formaldehyde condensate
732 g of diisopropylnaphthalene
314 g of a high-boiling aliphatic hydrocarbon
mixture
(boiling range 230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and
12 g
of N-benzoylleuco methylene blue
131 g of methyl methacrylate
56 g of butanediol diacrylate
1.4 g of azobisisobutyronitrile
2 g of dimethyl 2,2-azobisisobutyrate.
The solids content of the dispersion obtained
was
~Q%~~'~~~
- 9 - O.Z. 0050/41614
48.5 ~ by weight, and efflux time from the Ford cup was
135 seconds.
The average particle size of the microcapsules is
5.4 ~m with a practical variation in size from 3 to 7 gym.
EXAMPLE 3
This dispersion was prepared in the manner of
Example from the following components:
1
1280 g of water
20 g of polyvinylpyrrolidone of K 90
15 g of phenolsulfonic acid/formaldehyde condensate
732 g of diisopropylnaphthalene
314 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 12 g
of N-benzoylleuco methylene blue ,
93.5 g of methyl mef:hacrylate
37.4 g of butanediol diacrylate
1.4 g of azobisisobutyronitrile
2 g of dimethyl 2,2-azobis:Lsobutyrate.
The
solids
content
of
the
dispersion
obtained
was
48.6 by weight, and efflux time from the Ford cup was
~
103 seconds.
The
average
particle
size
of
the
microcapsules
is
5.8 ~m with
a
practical
variation
in
sixa
from
3
to
8
gym.
EXAMPLE 4
This
dispersion
was
prepared
in
the
manner
of
Example from the following components:
1
1270 g of water
15 g of polyvinylpyrrolidone of R 90
15 g of phenolsulfonic acid/formaldehyde condensate
636 g of diisopropylnaphthalene
273 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 12 g
of N-benzoylleuco methylene blue
287 g of methyl methacrylate
33 g of acetoacetoxyethyl methacrylate
~fl~~ ~~9~
- ZO - O.Z. 0050/41614
5.5 g of azobisisobutyronitrile
2 g of dimethyl 2,2-azobisisobutyrate.
However, after 1 1/2 hours' polymerization
at
60C a
solution
of 4~.7
g of
formaldehyde
and
28 g
of
water was added over 1 hour, and the temperature
was
raised to 65C and left at that level for 1 I/2
hours.
The solids content of the dispersion obtained
was
48.2 by weight, and efflux time from the Ford
~ cup was
74 seconds.
The average particle size of the microcapsules
is
5.5 ~m with a practical variation in size from
3 to 8 gym.
EXAMPLE 5
This dispersion was pxepared in the manner
of
~;xample
1 from
the
following
components:
1280 g of water
g of polyvinylpyrrolidone of R 90
15 g of phenolsulfonic acid/formaldehyde condensate
522 q of diisopropylnaphthalene
522 g of dodecylbenzene
20 48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and
12 g
of N-benzoylleuco methylene blue
19 g of ethyl acrylate
9 g of ethyl methacrylate
19 g of 2-ethylhexylacrylate
112 g of methyl methacrylate
28 g divinylbenzene
1.4 g azobisisobutyronitrile
2 g of dimethyl 2,2-azobisisobutyrate.
The solids content of 'the dispersion obtained
was
43.5 by weight, and efflux time from the Ford
~ cup was
106 seconds.
The average particle size of the microcapsules
is
5.8 ~m with a practical variation in size from
3 to 12 gym.
EXAMPLE 6
This dispersion was prepared in the manner of
Example 1 from the following components:
1464 g of water
50 g of polyvinylpyrrolidone of R 90
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g of polyacrylic acid of K 50
645 g of diisopropylnaphthalene
285 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265°C)
5 50 g of a mixture of 35.5 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 12.5
g of N-benzoylleuco methylene blue
120 g of methyl methacrylate
2 g of azobisisobutyronitrile
10 30 g of a 20 ~ strength nonaqueous dispersion of a
methacrylate copolymer in cyclohexane (meth-
acrylic acid content 4.8 ~).
However, after heating at 65°C the polymerization
was initially carried out at that temperature for 2 1/2
hours and then at 70°C for 2 1/4 hours.
T;he solids content of the dispersion obtained was
41.6 ~ lay weight, and efflux time from the Ford cup was
50 seconds.
The average particle size of the microcapsules is
5.2 ~m with a practical variation in size from 2 to 6 gym.
EXAMPLE 7
This dispersion was prerpared in the manner of
Example 6 from the following components:
1334 g of water ,
45 g of polyvinylpyrrolidone of K 90
11 g of polyacrylic acid of K 50
732 g of diisopropylnaphthalene
313 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265°C)
55 g of a mixture of 41 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 14 g
of N-benzoylleuco methylene blue
187 g of methyl methacrylate
3.1 g of azobisisobutyronitrile
45 g of a 20 $ strength nonaqueous dispersion of a
methacrylate copolymer in cyclohexane (methacrylic acid
content 4.8 $).
The solids content of the dispersion obtained was
47 ~ by weight, and efflux time from the Ford cup was
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106 seconds.
The average particle size of the microcapsules is
5.4 ~m with a practical variation in size from 3 to 6 ~sm.
Application properties
The microcapsules of the present invention were
examined in respect of permeability, color intensity and
rub sensitivity.
To this end, the microcapsule dispersions were
diluted to a solids content of 16.5 ~ by weight and then
applied at a rate of 5 g of microcapsules per m2 to
a) standard typewriting paper and
typewriting paper which had been pretreated with
attapulgite as color developer,
after which these papers were dried.
A) Determination of the permeability
The permeability is a measure of the amount of
nonencapsulated color former.
To determine the permeability, paper ,B) was
slightly moistened with dodecylbenzene, causing the
nonencapsulated color former to become detached to form
a dye with the developer. The degree of coloring of the
papers thus treated was measured as the difference in
reflectance between an unsprayed sheet of paper ,9) and a
sprayed sheet in a reflectance photometer and expressed
in relative ~ units, with the reflectance of the un
sprayed sheet of paper p) being set equal to 100.
B) Determination of the color intensity
The color intensity in question here is the
intensity of a certain copy.
To determine the color intensity, a sheet of
paper «) was placed with the coated face on a sheet of
paper which had been coated with a color developer and a
further 3 layers of paper of 38 g/m2 were placed on top.
This pile was then clamped into an electric typewriter
and imprinted with a letter over an area of 4.2 x 3.4 cm
with maximum impression. The intensity of the fourth copy
was measured in a reflectance photometer as the dif-
ference in the reflectances of the typed and untyped
paper and reported in relative ~ units with the
- 13 - O.Z. 0050/41614
reflectance of the untyped sheet being set equal to 100.
C) Determination of the rub sensitivity
The rub value is a measure of the coloring pro-
duced by rubbing only.
To determine the rub value, a sheet of paper
« ) was placed on top of a sheet of paper coated with a
color developer and the sheet of paper a) was pulled
slowly and uniformly over the developer-coated paper
underneath with a circular, flat weight of 2.1 N/cm2
placed on top.
Then the developer-coated paper was stored in the
dark for 1 hour, and afterwards its degree of coloring
was measured in a reflectance photometer as the
difference in the reflectances of the rubbed and unrubbed
sheets and reported in relative $ units with a reflect
ance of the unrubbed sheet being set equal to 100.
The table shows the results of test A, B and C.
TABLE
Application properties of microcapsules of Examples 1
to 5
Example Permeability Color intensity Rub value
1 43 29.8 23.7
2 7 38.8 15.5
3 10 42.0 19.8
4 43 23.3 15.3
5 27 28.5 38.5
EXAMPLE 8
A mixture ofa
1287 g of water
20 g of polyvinylpyrrolidone of R 90
18 g of a phenolsulfonic acid-formaldehyde conden-
sate
770 g of diisopropylnaphthalene
330 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265°C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 12 g
- 14 - 0.2. 0050/41614
of N-benzoylleuco methylene blue
131 g of methyl methacrylate
56 g of butanediol diacrylate
3.4 g of t-butyl perpivalate
was treated as described in Example 1. It was polymerized
at 51°C for 2 hours and then at increasing temperature up
to 72°C for 4 hours.
EXAMPLE 9
A mixture of:
1293 g of water
g of palyvinylpyrrolidone of K 90
27 g of a phenolsulfonic acid-formaldehyde conden-
sate
770 g of diisopropylnaphthalene
15 330 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265°C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 12 g
of N-benzoylleuco methylene blue
20 131. g of methyl methacxylate
56 g of butanediol diacrylate
1.4 g of azobisisobutyronitrile
1 g of dimethyl 2,2-azobisisobutyrate
was treated as described in Examp7.e 1. It was polymerized
at 65°C for 2 hours and then at increasing temperature
up to 71°C for 4 hours.
EXAMPLE 10
A mixture of:
1287 g of water
20 g of polyvinylpyrrolidone of K 90
18 g of a phenolsulfonic acid-formaldehyde
conden-
sate
770 g of diisopropylnaphthalene
330 g of a high-boiling aliphatic hydrocarbon
mixture
(boiling range 230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-diznethyl-
aminophenyl)-6-dimethylaminophthalide
and 12 g
of N-benzoylleuco methylene blue
131 g of methyl methacrylate
~~ ~.~?
- 15 - O.Z. 0050/41614
56 g of butanediol diacrylate
1.4 g of azobisisobutyronitrile
2 g of dimethyl 2,2-azobisisobutyrate
was ed as described in Example 1. It was polymerized
treat
at 60 C
for
2
hours
and
then
at
increasing
temperature
up to 75 C for 4 hours.
EXAMPLE 11
A mixture of:
1287 g of water
20 g of polyvinylpyrrolidone of K 90
18 g of a phenolsulfonic acid-formaldehyde conden-
sate
1 g of carboxymethylcellulose
770 g of diisopropylnaphthalene
330 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 12 g
of N-benxoylleuco methylene blue
137, g of methyl methacrylate
56 g of butanediol diacrylai:e
1.4 g of azobisisobutyronitrile
?. g of dimethyl 2,2-azobisjtsobutyrate
was
treated
as
described
in
Example
1.
EXAMPLE 12! .
A mixture of:
1287 g of water
20 g of polyvinylpyrrolidone of K 90
18 g of a phenolsulfonic acid-formaldehyde conden-
sate
1.3 g of polyacrylic acid
770 g of diisopropylnaphthalene
330 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 12 g
of N-benxoyllauco methylene blue
131 g of methyl methacrylate
56 g of butanediol diacrylate
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1.4 g of azobisisobutyronitrile
2 g of dimethyl 2,2-azobisisobutyrate
was
treated
as
described
in
Example
1.
It
was
polymerized
at 60 C 2 hours and then at 65C for 4 hours.
for
EXAMPLE 13
A mi xture of:
1287 g of water
20 g of polyvinylpyrrolidone of R 90
18 g of a phenolsulfonic acid-formaldehyde conden-
sate
770 g of diisopropylnaphthalene
330 g of a high-boiling aliphatic hydrocarbon mixture
(boiling
range
230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
am inophenyl)-6-dimethylaminophthalide and 12 g
of PI-benzoylleuco methylene blue
131 g of methyl methacrylate
56 g of 1,3-propanediol diacrylate
7..4 g of azobisisobutyronitrale
2 g of dimethyl 2,2-azobisasobutyrate
was
treated
as
described
in
Example
1.
It
was
polymerized
at 60 C 2 hours and then at li5C for 4 hours.
for
EXAMPLE 14
A mixture
of:
1287 g of water
20 g of polyvinylpyrrolidonEa of I~ 90
18 g of a phenolsulfonic acid-formaldehyde conden-
sate
770 g of diisopropylnaphthalene
330 g of a high-boiling aliphatic hydrocarbon mixture
(boiling
range
230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide
and
12
g
of N-benzoylleuco methylene blue
131 g of methyl methacrylate
56 g of hexanediol diacrylate
1.4 g of azobisisobutyronitrile
2 g of dimethyl 2,2-azobisisobutyrate
was
treated
as
described
in
Example
1.
It
was
polymerized
~fl~~.~~
- 17 - O.Z. 0050/41614
at 60°C for 2 hours and then at 65°C for 4 hours.
EXAMPLE 15
A mixture of:
1287 g of water
20 g of polyvinylpyrrolidome of K 90
18 g of a phenolsulfonic acid-formaldehyde conden-
sate
770 g of diisopropylnaphthalene
330 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 12 g
of N-benzoylleuco methylene blue
131 g of methyl methacrylate
56 g of butanediol diacrylate
5.4 g of bis(3,5,5-trimethylhexanoyl) peroxide
was treate d as described in Example 1. It was polymerized
at 52 C
for
2
hours
and
then
at
59C
for
4
hours.
EXAMPLE 16
A mixturd of:
1287 g of water
20 g of polyvinylpyrrolidone of K 90
18 g of a phenolsulfonic ac:Ld-formaldehyde conden-
sate
1 g of carboxymethylcellulose
770 g of diisopropylnaphthalene
330 g of a high-boiling aliphatic hydrocarbon mixture
(boiling range 230-265C)
48 g of a mixture of 36 g of 3,3-bis(p-dimethyl-
aminophenyl)-6-dimethylaminophthalide and 12 g
of N-benzoylleuco methylene blue
131 g of methyl methacrylate
56 g of butanediol diacrylate
1.4 g of azobisisobutyronitrile
2 g of dimethyl 2,2-azobisisobutyrate
Al l ingredients except the monomers and the
initiators were dispersed at room temperature for
5 minutes. The remaining substances were then added and
dispersing was continued for a further 15 minutes. The
?v~~. ~~?
- 18 - O.Z. 0050/41614
mixture was polymerized at 60°C for 2 hours and then at
65°C for 4 hours.
EXAMPLE 17
A mixture of:
128 g of water
2 g of polyvinylpyrrolidone of K 90
1.8 g of a phenolsulfonic acid-formaldehyde conden-
sate
13.1 g of methyl methacrylate
ZO 5.6 g of butanediol diacrylate
88 g of di(2-ethylhexyl) phthalate
22 g of a scent
0.14 g of azobisisobutyronitrile
0.2 g of dimethyl 2,2-azobisisobutyrate
All the ingredients were dispersed at room
temperature for 3 minutes . The mixture was polymerized at
60°C for 2 hours and then at 65°C for 4 hours. The scent-
containincr microcapsules have a diameter within the range
from 2 to 5 um.
EXAMPLE 18
A mixture of:
128 g of water
2 g of polyvinylpyrrolidone of K 90
1.8 g of a phenolsulfonic acid-formaldehyde conden-
sate
13.1 g of methyl methacrylate
5.6 g of butanediol diacrylate
110 g of mstolachlor
0.14 g of azobisisobutyronitrile
0.2 g of dimethyl 2,2-azobisisobutyrate
All the ingredients were dispersed at room
temperature for 3 minutes. The mixture was polymerized at
60°C for 2 hours and then at 65°C for 4 hours. The
microcapsules containing the crop protection agent have
a diameter within the range from 3 to 8 ~sm.
EXAMPLE 19
A mixture of:
128 g of water
2 g of polyvinylpyrrolidone of R 90
~~~.'~~~
- 19 -~ O.Z. 0050/41614
1.8 g of a phenolsulfonic acid-formaldehyde conden-
sate
18.6 g of methyl methacrylate
8B g of lead(II) 2-ethylhexanoate
22 g of white oil
0.1 g of azobisisobutyronitrile
0.2 g of dimethyl 2,2-azobisisobutyrate
All the ingredients were dispersed at room
temperature for 5 minutes. The mixture was polymerized
at 60 °C for 2 hours and then at 65 °C for 4 hours . The
microcapsules containing the lead salt have a diameter
within the range from 2 to 6 um.
Examples 8 to 19 likewise produce microcapsules
having properties similar to those of Examples 1 to 7.
