U.S. patent application number 13/347744 was filed with the patent office on 2012-05-03 for storage-stable, hydroxy-modified microgel latices.
This patent application is currently assigned to LANXESS Deutschland GmbH. Invention is credited to Werner Obrecht.
Application Number | 20120108724 13/347744 |
Document ID | / |
Family ID | 41480341 |
Filed Date | 2012-05-03 |
United States Patent
Application |
20120108724 |
Kind Code |
A1 |
Obrecht; Werner |
May 3, 2012 |
STORAGE-STABLE, HYDROXY-MODIFIED MICROGEL LATICES
Abstract
A composition is described, encompassing a constituent selected
from the group consisting of a modified resin acid (I), a fatty
acid (II) and a mixture composed of a modified resin acid (I) and
of a fatty acid (II), where the degree of neutralisation of the
constituent is from 104 to 165%. Its use for the production of
microgels is also described.
Inventors: |
Obrecht; Werner; (Moers,
DE) |
Assignee: |
LANXESS Deutschland GmbH
Leverkusen
DE
|
Family ID: |
41480341 |
Appl. No.: |
13/347744 |
Filed: |
January 11, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12614587 |
Nov 9, 2009 |
8119728 |
|
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13347744 |
|
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Current U.S.
Class: |
524/300 |
Current CPC
Class: |
C08L 21/00 20130101;
C08F 36/04 20130101; C08L 15/00 20130101; C08L 93/04 20130101; B60C
1/0016 20130101; C08F 2/22 20130101; C08F 36/04 20130101; C08F
36/04 20130101; C08F 2/22 20130101; C08C 19/38 20130101; C08K 5/098
20130101; C08K 5/098 20130101; C08L 15/00 20130101; C08F 2/26
20130101; C08L 21/00 20130101; C08L 9/00 20130101 |
Class at
Publication: |
524/300 |
International
Class: |
C08L 33/02 20060101
C08L033/02; C08K 5/09 20060101 C08K005/09 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 2008 |
DE |
10 2008 056 975.5 |
Claims
1. A composition, comprising: a mixture of a modified resin acid
and of a fatty acid, wherein the degree of neutralisation of the
mixture is from 104 to 165%.
2. The composition according to claim 1, wherein the ratio by
weight of modified resin acid to fatty acid is from 0.05:1 to
15:1.
3. The composition according to claim 1, wherein the modified resin
acid is disproportionated resin acid.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/614,587, filed Nov. 9, 2009, pending,
entitled "STORAGE-STABLE, HYDROXY-MODIFIED MICROGEL LATICES", which
claims priority to German application 10 2008 056 975.5, the
contents of which are hereby incorporated by reference in their
entirety.
[0002] The present invention relates to microgels and to emulsifier
compositions which are used in the production of the said
microgels. The present invention further relates to a process for
the production of the microgels and of the emulsifier compositions.
The present invention also relates to the use of the emulsifier
composition for the production of microgels.
[0003] Microgels and rubber particles are examples of the various
terms used for microgels. Microgels are described inter alia in EP
0 405 216 A, DE 42 20 563 A, DE 197 01 488 A and DE 197 01 487 A.
Microgels are used, for example, to improve the processability of
rubber mixtures, and also to improve the properties of
vulcanisates, in particular to improve physical properties such as
modulus, ultimate tensile strength, abrasion resistance, rolling
resistance, heat-build-up under dynamic load and wet slip
resistance. These property improvements make microgels particularly
suitable for use in the production of various tyre components, in
particular of tyre treads.
[0004] Functionalised microgels are also known. Functional
microgels are described by way of example in EP 1 152 030 A, EP 1
664 158 A, EP 1 149 866 A, EP 1 149 867 A, EP 1 298 166 A, EP 1 291
369 A, EP 1 245 630 A and EP 1 520 732 A, and hydroxy-modified
microgels are of particular interest here. Hydroxy-modified
microgels are used by way of example in polyurethanes (cf. DE 199
19 459 A). In the production of tyre treads, hydroxy-modified
microgels are frequently used in combination with silica-containing
fillers, giving tyres with improved driving performance.
[0005] In order to achieve good vulcanisate properties, the
functionalised, for example hydroxy-modified, gels are "activated"
or "coupled" to the rubber matrix during vulcanisation. Suitable
activators are sulphur-containing organosilicon compounds (EP 1 063
259 A), multifunctional isocyanates (EP 1 110 986 A),
isocyanatosilanes (WO 02/12389 A), and also phenolic resin educts
(WO 02/32990 A). It is also known that high content of superficial
hydroxy groups is necessary in order to achieve good physical
properties of the gel-containing vulcanisates (EP 1 520 732 A).
There is consequently a demand for microgels which have a high
hydroxy group content.
[0006] Two particular processes are used for the production of
these hydroxy-modified microgels:
[0007] In a first process, for introduction of functional groups
via grafting, monomers having functional groups are grafted onto an
unmodified microgel in the latex phase. The hydroxy modifiers used
are, for example, the acrylates or methacrylates of hydroxy
ethanol, hydroxy propanol and hydroxy butanol. The unmodified
microgel used as graft base is obtained, for example, via
crosslinking of a substantially uncrosslinked rubber latex by means
of dicumyl peroxide (DE 100 35 493 A). This procedure for the
production of hydroxy-modified microgels is very complicated,
because it requires a large number of steps in the process.
[0008] In a second process, the latices of the hydroxy-modified
microgels are obtained via copolymerisation (of more than two
monomers) in a reaction step via emulsion processes. Corresponding
procedures are described in EP 1 664 158 A, EP 1 149 866 A, EP 1
149 867 A, EP 1 298 166 A, EP 1 291 369 A and EP 1 245 630 A. The
emulsifier systems used in the patent specifications mentioned are
based on sulphonic acids, modified resin acids, fatty acids and
mixtures of the same.
[0009] Use of emulsifier mixtures based on sulphonic acid (EP 1 664
158 A) or of emulsifier mixtures based mainly on sulphonates and on
very small amounts of carboxylates give latices of the hydroxylated
microgels with sufficiently high latex stability. However,
coagulation of these rubber latices produces very fine crumb of
diameter less than 2 mm, and it is not possible to use sieves on an
industrial scale to separate this quantitatively from latex serum.
The result is considerable yield losses.
[0010] Use of emulsifiers based on modified resin acids (EP 1 149
866 A, EP 1 149 867 A and EP 1 298 166 A) or of mixtures of
modified resin acid with fatty acid with no precise definition of
proportions (EP 1 291 369 A and EP 1 245 630 A) produces latices
which give adequately large crumb on coagulation, and can therefore
be separated from latex serum without yield losses, for example by
using sieves.
[0011] However, the hydroxylated latices produced in this way have
inadequate stability. For the purposes of the invention, inadequate
stability in particular means that there is a possibility of latex
coagulation during the emulsion polymerisation process, latex
coagulation during the removal of volatile constituents by steam
distillation, latex coagulation during transport of the latices by
pumping, and particle-size change and/or latex coagulation during
latex storage.
[0012] This inadequate latex stability leads in particular to the
following disadvantages: [0013] 1) During the polymerisation
process, polymer deposits form on the reactor wall. This reduces
reactor operating times and increases cleaning cost. [0014] 2)
During removal of unreacted monomers by steam distillation, partial
or complete coagulation of the latices occurs. This significantly
reduces yields, and considerable cost is incurred for cleaning the
assemblies in which the steam distillation process is carried out.
[0015] 3) Partial or quantitative latex coagulation takes place
during procedures involving pumped circulation, because of reduced
shear resistance. This likewise significantly reduces yields.
[0016] 4) When the hydroxylated microgels are produced according to
the teaching of the prior art, the result is an increase in the
apparent diameter of the latex particles and latex coagulation
during latex storage, without any application of shear forces.
[0017] The latex-stability problems mentioned particularly occur
with microgels having hydroxy contents above 5% by weight.
[0018] In view of the prior art described, a first object of the
present invention is to provide microgels which contain hydroxy
groups and which have adequate stability in the latex state, and
which provide crumb of adequate size during latex coagulation.
[0019] The microgels should moreover preferably have high gel
content, in particular of more than 70% by weight.
[0020] A further intention is that the present invention also in
particular achieve the object of providing microgels with maximum
hydroxy content, determined as hydroxy number (OH number).
[0021] A final intention is that the present invention in
particular also achieve the object of providing microgels with a
swelling index smaller than 30.
[0022] Another object of the present invention, in respect of the
production of the desired microgels, is to provide a procedure for
the production of microgels with improved shear resistance and
improved storage stability. The intention is that the resultant
microgels preferably be produced in a cost-effective manner using
short polymerisation times, particularly preferably using
polymerisation times below 10 hours, and preferably with high
polymerisation conversions, particularly preferably with
polymerisation conversions of more than 80%.
[0023] The microgels obtained via the process of the invention are
moreover intended to provide, during latex coagulation, adequately
large crumb, preferably measuring more than 5 mm, easily capable of
separation from latex serum by way of sieves.
[0024] The said object is achieved via the use of a specific
emulsifier composition, used for the production of the
microgels.
[0025] The present invention therefore firstly provides an
emulsifier composition.
[0026] The emulsifier composition of the invention is characterized
in that it encompasses at least one constituent selected from the
group consisting of a modified resin acid (I), a fatty acid (II)
and a mixture composed of a modified resin acid (I) and of a fatty
acid (II), where the degree of neutralisation of the constituent is
from 104 to 165%.
[0027] The degree of neutralisation here is based either on one of
the individual compounds of the modified resin acid (I) and,
respectively, fatty acid (II) or else on the entire mixture
composed of modified resin acid (I) and fatty acid (II).
[0028] According to the invention, it has been found that use of
the said specific emulsifier composition in the production of
microgels via emulsion polymerisation gives microgels which have
improved shear resistance and improved storage stability.
[0029] At the same time, the quality of the resultant microgels
with regard to other physical properties is at least equal to the
quality of the conventional microgels known from the prior art.
[0030] The resultant microgels here can generally have more than
70% by weight gel content, preferably more than 75% by weight,
particularly preferably more than 80% by weight.
[0031] The microgels obtained using the emulsifier composition of
the invention moreover generally have a swelling index of less than
30, preferably less than 25, particularly preferably less than
20.
[0032] The microgels moreover have more than 0.1% by weight content
of copolymerised monomers containing hydroxy groups. The hydroxy
number of the resultant microgels is generally greater than
0.5.
[0033] The microgels can moreover preferably be obtained in a
cost-effective manner using short polymerisation times,
particularly preferably using polymerisation times below 10 hours,
and preferably with high polymerisation conversions, particularly
preferably with polymerisation conversions higher than 80%.
[0034] Finally, the microgels give sufficiently large crumb during
latex coagulation, preferably measuring more than 5 mm, so that
this can be separated from the latex serum efficiently by way of
sieves.
Emulsifier System
[0035] The present invention provides an emulsifier system in which
at least one modified resin acid (I) and at least one fatty acid
(II) is used.
[0036] However, for the purposes of the present invention, it is
also possible to use a plurality of different modified resin acids
(I) in the emulsifier composition of the invention, for example 2,
3, 4 or 5 different resin acids.
[0037] However, for the purposes of the present invention, it is
also possible to use a plurality of different modified fatty acids
(I) in the emulsifier composition of the invention, for example 2,
3, 4 or 5 different fatty acids.
[0038] The use of the alkali metal salts of fatty acids in the
production of polymers has been known for a long time (Methoden der
organischen Chemie [Methods of organic chemistry], Houben-Weyl,
Volume XIV/1, Makromolekulare Stoffe [Macromolecular substances],
Part 1, pages 192-194, Georg Thieme Verlag, 1961). The chain length
of the fatty acids is from 6 to 22 carbon atoms. Mono- or
polyunsaturated fatty acids are also suitable. The acids can, as
mentioned, be used alone or in the form of a mixture of acids of
different chain length. If a mixture is used, the proportion of
fatty acids having chain lengths of from 16 to 18 carbon atoms
should be .gtoreq.80%.
[0039] For the purposes of the present invention, it is also
possible to make simultaneous use of a plurality of different
modified resin acids (I) with a plurality of different fatty acids
(II).
[0040] For the purposes of the present invention, a modified resin
acid (I) is a resin acid which has been obtained via dimerisation,
disproportionation and/or hydrogenation of unmodified resin acids.
Appropriate modified resin acids are obtained by starting from
unmodified resin acids which in turn by way of example are selected
from the group consisting of pimaric acid, neoabietic acid, abietic
acid, levopimaric acid and palustric acid, by using the
modification methods mentioned.
[0041] In one particularly preferred embodiment of the present
invention, the modified resin acid is a disproportionated resin
acid (Ullmann's Encyclopedia of Industrial Chemistry, 6th Edition,
Volume 31, pp. 345-355). The preferred disproportionated resin acid
is commercially available as modified resin acid.
[0042] The resin acids used are tricyclic diterpene carboxylic
acids obtained from roots, pine balsam and tall oil. These
"unmodified" resin acids can by way of example be converted as
described in W. Bardendrecht, L. T. Lees in Ullmanns Encyclopadie
der Technischen Chemie [Ullmann's Encyclopaedia of Industrial
Chemistry], 4th Edition, Vol. 12, 525-538, Verlag Chemie,
Weinheim--New York 1976 to give disproportionated resin acids. In
the form of their alkaline metal salts, disproportionated resin
acids are mainly used as emulsifiers for the production of polymers
and latices (W. Barendrecht, L. T. Lees in Ullmanns Encyclopadie
der Technischen Chemie [Ullmann's Encyclopaedia of Industrial
Chemistry], 4th Edition, Vol. 12, 530, Verlag Chemie, Weinheim--New
York 1976).
[0043] The composition of the invention also encompasses at least
one fatty acid (II) alongside the modified resin acid (1).
[0044] The fatty acids preferably contain from 6 to 22 carbon atoms
per molecule, particularly preferably from 6 to 18 carbon atoms per
molecule. They can be completely saturated acids or can contain one
or more double bonds or triple bonds within the molecule.
[0045] Examples of fatty acids suitable according to the invention
are caproic acid, lauric acid, myristic acid, palmitic acid,
stearic acid, oleic acid, linoleic acid and linolenic acid.
[0046] In another embodiment of the present invention, the
carboxylic acids can also be present in mixtures from specific
sources, examples being castor oil, cottonseed, peanut oil, linseed
oil, coconut fat, palm kernel oil, olive oil, rapeseed oil, soybean
oil, fish oil and bovine tallow (Ullmann's Encyclopedia of
Industrial Chemistry, 6th Edition, Volume 13, pp. 75-108).
[0047] Preferred carboxylic acids derive from bovine tallow and are
partially hydrogenated acids. Particular preference is therefore
given to partially hydrogenated tallow fatty acid.
[0048] The resin acids and the fatty acids are commercially
available in the form of free carboxylic acids, or in partially or
fully neutralised form.
[0049] In order to determine the alkali metal addition necessary
for the polymerisation process, the resin acids and fatty acids to
be used are characterized via acidimetric titration (Maron, S. H.,
Ulevitch, I. N., Elder, M. E. "Fatty and Rosin Acids, Soaps, and
Their Mixtures", Analytical Chemistry, Vol. 21, 6, 691-695; Maron,
S. H.; Madow, B. P.; Borneman, E. "The effective equivalent weights
of some rosin acids and soaps", Rubber Age (1952), 71-72). In this
way the amounts of free carboxylic acids and of emulsifier salts
are determined, in order to calculate the amounts to be added for
the targeted adjustment of the degrees of neutralisation of the
resin/fatty acid mixtures used in the polymerisation.
[0050] The emulsifiers being mixtures with unknown average molar
weight, the precise adjustment of the degree of neutralisation in
the first step necessitates a titrimetric characterisation of the
emulsifiers employed, which is carried out preferably by the above
procedure.
[0051] The degree of neutralisation of the emulsifiers (R--COOH)
containing carboxy groups is calculated on the basis of the
following stoichiometric formula; if the degree of neutralisation
here is 100%, all of the carboxy groups of the emulsifier have been
neutralised with an equimolar amount of a metal hydroxide compound
(MeOH).
##STR00001##
[0052] The degree of neutralisation of the resin/fatty acid mixture
is important for achievement of good latex stabilities. The degree
of neutralisation of the resin acids (I) and of the fatty acids
(II) is preferably from 104 to 165%, preferably from 106 to 160%,
with particular preference from 110 to 155%; a degree of
neutralisation of 100% here means complete salt formation, and a
degree of neutralisation of more than 100% here means a
corresponding excess of base.
[0053] Examples of bases that can be used for the neutralisation of
the resin acids and fatty acids are LiOH, NaOH, KOH, NH.sub.3
and/or NH.sub.4OH. Preference is given here to bases which do not
form sparingly soluble salts with the acids. Particularly preferred
bases are LiOH, NaOH, KOH and NH.sub.4OH.
[0054] The neutralisation of the carboxylic acids here can take
place prior to the actual use of the emulsifier composition, but is
preferably in-situ neutralisation when the materials are charged to
the reactor, or in a separate container prior to addition to the
polymerisation reactor.
[0055] The resin acids and fatty acids are used as emulsifier in
the production of microgels, in the form of single component or
jointly; the amount of resin acid or fatty acid here, or the total
amount of resin acid and fatty acid, is from 2.2 to 12.5 parts by
weight, preferably from 2.5 to 10 parts by weight, particularly
preferably from 2.8 to 7.5 parts by weight, based in each case on
100 parts by weight of the monomer mixture.
[0056] The ratio by weight between the salts of resin acid (I) and
fatty acid (II) is preferably from 0.05:1 to 15:1, particularly
preferably from 0.08:1 to 12:1.
[0057] The emulsifier composition of the invention can comprise
further constituents alongside the essential constituents of at
least one salt of a resin acid (I) and of at least one salt of a
fatty acid (II).
[0058] The emulsifier composition of the invention can therefore,
for example, additionally encompass neutral and anionic
emulsifiers.
[0059] The use of further emulsifiers is possible, but not
compulsory, in particular during the polymerisation process, and
also in the form of subsequent addition after the polymerisation
process for the production of the microgels. Anionic and non-ionic
emulsifiers can be used. Examples of anionic emulsifiers are alkyl
sulphates, such as n-dodecyl sulphate (e.g. Texapon.RTM. K12 from
Cognis); alkylsulphonates (e.g. Mersolat.RTM. K30 from Lanxess
Deutschland GmbH); arylsulphonates (e.g. Marlon.RTM. from Sasol
Germany GmbH); methylene-bridged bisnaphthalenesulphonates (e.g.
Baykanol.RTM. PQ from Lanxess Deutschland GmbH); and mono- and
diesters of sulphosuccinic acid (sodium salt of dioctyl
sulphosuccinic acid). Suitable non-ionic emulsifiers are
polyethylene oxide and polypropylene oxide, and also copolymers of
these two monomers. Adducts of ethylene oxide and propylene oxide
onto aliphatic and aromatic phenols, and also onto amines, are also
suitable. It is also possible to use polymeric neutral or anionic
stabilisers. Examples here are polyvinyl alcohol,
hydroxyalkylcelluloses, polyvinylpyrrolidone and sodium
polyacrylate.
[0060] Use of the neutral and anionic emulsifiers firstly improves
latex stability; secondly, the rubber crumb produced on coagulation
of the latices is smaller. For this reason, it is preferable to
exert control over the selection and amount of the neutral and
anionic emulsifiers added. The amount added of anionic emulsifiers,
if these are used, is usually in the range from 0 to 0.5 part by
weight, preferably from 0 to 0.25 part by weight, particularly
preferably from 0 to 0.10 part by weight.
[0061] The above emulsifier composition is preferably used in the
production of microgels.
[0062] The present invention therefore also provides the use of the
above composition as emulsifier system, in particular for the
production of storage-stable dispersions of microgels containing
hydroxy groups, and for the purposes of the present invention
storage-stable dispersions here are microgels which contain hydroxy
groups and which do not exceed a certain increase in particle
diameter as a function of storage time.
[0063] The present invention further provides a process for the
production of a microgel in which the composition defined above is
used as emulsifier.
[0064] The microgels thus obtained can have from 10 to 100% by
weight gel content, and it is possible here, by using the
emulsifier composition of the invention, to produce microgels with
gel content which is generally more than 70% by weight, preferably
more than 75% by weight, particularly preferably more than 80% by
weight.
[0065] The microgels obtained using the emulsifier composition of
the invention moreover have a swelling index which is generally
less than 30, preferably less than 25, particularly preferably less
than 20.
[0066] The microgels moreover have more than 0.1% by weight content
of copolymerized monomers containing hydroxy groups. The hydroxy
number of the resultant microgels is generally more than 0.5.
[0067] The microgels here are preferably produced by emulsion
polymerisation.
[0068] For the purposes of the present invention, the amount of the
emulsifier composition of the invention used in the process of the
invention is preferably at least 2.2 parts by weight, particularly
preferably at least 2.5 parts by weight, based in each case on the
monomer composition defined in more detail at a later stage
below.
[0069] For the purposes of the present invention, the amount of the
emulsifier composition of the invention used in the process of the
invention is preferably from 2.2 to 12.5 parts by weight,
preferably from 2.5 to 10 parts by weight, particularly preferably
from 2.8 to 7.5 parts by weight, based in each case on 100 parts by
weight of the monomer mixture.
[0070] Particularly preferred ranges are amounts of from 2.2 to
10.00% by weight, more preferably from 2.5 to 8.00% by weight.
[0071] The polymerisation reaction is preferably carried out at a
temperature of from 10 to 100.degree. C., particularly preferably
from 12 to 90.degree. C., in particular from 15 to 50.degree.
C.
[0072] The emulsion polymerisation reaction here can be carried out
by an isothermal, semiadiabatic or completely adiabatic
procedure.
[0073] The process of the invention can moreover encompass a
coagulation process step carried out at temperatures above the
glass transition temperature of the microgel. The coagulation
temperatures here are preferably higher than the glass transition
temperature of the microgel by at least 10.degree. C., particularly
at least 15.degree. C., in particular at least 20.degree. C.
Compliance with the said coagulation temperatures provided
according to the invention has a codeterminant effect on the crumb
size of the resultant microgels.
[0074] There follows a more detailed explanation of the
constituents used alongside the emulsifier composition in the
process of the invention.
Monomers
[0075] Production of the microgels uses monomer mixtures composed
of conjugated dienes (A), of vinylaromatic monomers (B), of
crosslinking monomers (C) and of monomers (D) containing hydroxy
groups, where the total amount of the monomers is 100 parts by
weight. It is moreover possible, in another embodiment of the
present invention, to produce a hydroxylated crosslinked microgel
from only three components, namely constituents (A), (C) and (D),
or (B), (C) and (D).
[0076] Preferred conjugated dienes (A) used are 1,3-butadiene,
isoprene, 2,3-dimethyl-1,3-butadiene and chloroprene. Preference is
given to 1,3-butadiene and isoprene.
[0077] It is preferable to use from 0 to 94.9% by weight of the
diene (A), with preference from 0 to 94.0% by weight, with
particular preference from 0 to 93.5% by weight, based in each case
on 100 parts by weight of the monomers used in the polymerisation
reaction.
[0078] Examples of vinylaromatic monomers (B) used are styrene,
.alpha.-methylstyrene, 2-methylstyrene, 3-methylstyrene,
4-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene,
4-tert-butylstyrene or tert-butoxystyrene. Preference is given to
styrene and .alpha.-methylstyrene. The amount used of the
vinylaromatic monomers (B) is generally from 0 to 94.9% by weight,
preferably from 0 to 94.0% by weight, particularly preferably from
0 to 93.5% by weight, based in each case on 100 parts by weight of
the monomers used in the polymerisation reaction.
[0079] Crosslinking monomers (C) used are monomers which contain at
least 2 double bonds in the molecule. Among these are the
(meth)acrylates of diols having from 1 to 20 carbon atoms, e.g.
ethanediol di(meth)acrylate, 1,2-propanedial di(meth)acrylate,
1,3-propanedial (meth)acrylate, 1,2-butanediol di(meth)acrylate,
1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate,
1,6-hexanediol di(meth)acrylate (C1), polyethylene glycol
di(meth)acrylates and polypropylene glycol di(meth)acrylates, and
also diols based on copolymers of ethylene oxide and propylene
oxide having degrees of polymerisation of from 1 to 25 (C2), diols
based on polymerized tetrahydrofuran having degrees of
polymerisation of from 1 to 25 (C3), the bis- and
tris(meth)acrylates of trihydric alcohols, e.g. trimethylolpropane
di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerol
di(meth)acrylate and glycerol tri(meth)acrylate (C4), the bis-,
tris- and tetra(meth)acrylates of tetrahydric alcohols, e.g.
pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate
and pentaerythritol tetra(meth)acrylate (C5), aromatic polyvinyl
compounds (C6), e.g. divinylbenzene, diisopropenylbenzene,
trivinylbenzene, and also other compounds having at least two vinyl
groups, e.g. triallyl cyanurate, triallyl isocyanurate, vinyl
crotonate and allyl crotonate (C7). Preference is given to the
ethanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol,
trimethylolpropane, and pentaerythritol esters of (meth)acrylic
acid, and also to the aromatic polyvinyl compound
divinylbenzene.
[0080] The amount used of the crosslinking monomers (C) is from
0.1% by weight to 15% by weight, preferably from 0.5 to 12.5% by
weight, particularly preferably from 1 to 7.5% by weight, based in
each case on 100 parts by weight of the monomers used in the
polymerisation reaction.
[0081] A parameter especially affecting the gel content and the
swelling index of the microgels, alongside a number of other
parameters, such as the amount of regulator, the conversion in the
polymerisation reaction and the polymerisation temperature, is the
amount of crosslinking monomer (C). The monomer (C) also increases
the glass transition temperature of corresponding non-crosslinked
homo- and/or copolymers composed of the monomers (A) and (B).
[0082] Monomers (D) used which contain hydroxy groups are generally
hydroxyalkyl (meth)acrylates (D1), hydroxyalkyl crotonates (D2),
mono(meth)acrylates of polyols (D3), hydroxy-modified unsaturated
amides (D4), aromatic vinyl compounds (D5) containing hydroxy
groups, and also other monomers (D6) containing hydroxy groups.
[0083] Examples of hydroxyalkyl (meth)acrylates (D1) are
2-hydroxyethyl (meth)acrylate, 3-hydroxyethyl (meth)acrylate,
2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate,
2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate and
4-hydroxybutyl (meth)acrylate.
[0084] Examples of hydroxyalkyl crotonates (D2) are 2-hydroxyethyl
crotonate, 3-hydroxyethyl crotonate, 2-hydroxypropyl crotonate,
3-hydroxypropyl crotonate, 2-hydroxybutyl crotonate, 3-hydroxybutyl
crotonate and 4-hydroxybutyl crotonate.
[0085] Mono(meth)acrylates of polyols (D3) derive from di- and
polyhydric alcohols, e.g. ethylene glycol, propanediol, butanediol,
hexanediol, trimethylolpropane, glycerol, pentaerythritol, or else
from oligomerised ethylene glycol and propylene glycol, where these
contain from 1 to 25 of the glycol units mentioned.
[0086] Examples of hydroxy-modified unsaturated amides (D4) are
monomers such as N-hydroxymethyl(meth)acrylamide,
N-(2-hydroxyethyl)(meth)acrylamide and
N,N-bis(2-hydroxyethyl)(meth)acrylamide.
[0087] Aromatic vinyl compounds (D5) containing hydroxy groups are
2-hydroxystyrene, 3-hydroxystyrene, 4-hydroxystyrene,
2-hydroxy-.alpha.-methylstyrene, 3-hydroxy-.alpha.-methylstyrene,
4-hydroxy-.alpha.-methylstyrene and 4-vinylbenzyl alcohol.
[0088] An example of other monomers (D6) containing hydroxy groups
is (meth)allyl alcohol. The preferred amount used of the monomers
(D) containing hydroxy groups is from 0.1 to 20% by weight, with
preference from 0.5 to 15% by weight, particularly from 1 to 12.5%
by weight, based in each case on 100 parts by weight of the
monomers used in the polymerisation reaction.
[0089] The glass transition temperature of the microgel is
established via the ratio of the copolymerized monomers (A), (B),
(C) and (D). The glass transition temperature can be approximated
by using the Fox-Flory relationship, where the proportion by weight
of the monomers (A) and (B) is a decisive factor in arriving at a
first approximation of the glass transition temperature of the
microgel.
Tg = m A Tg A + m B Tg B ##EQU00001## [0090] Tg: glass transition
temperature of copolymer [0091] Tg.sub.A: glass transition
temperature of homopolymer A [0092] Tg.sub.B: glass transition
temperature of homopolymer B [0093] m.sub.A: proportion by weight
of monomer A [0094] m.sub.B: proportion by weight of monomer B
[0095] The Fox-Flory relationship advantageously uses the following
glass transition temperatures for the homopolymers of the monomers
(A) and (B), e.g. polybutadiene, polyisoprene, polystyrene,
poly-4-methylstyrene and poly(a)methylstyrene: [0096]
polybutadiene: -80.degree. C. [0097] polyisoprene: -65.degree. C.
[0098] polystyrene: 100.degree. C. [0099] poly-4-methylstyrene:
104.degree. C. [0100] poly(.alpha.)methyl styrene: 115.degree.
C.
[0101] Glass temperatures of other homopolymers of (A) and (B) are
found in J. Brandrup, E. H. Immergut, Polymer Handbook, Wiley &
Sons 1975.
[0102] The result of copolymerisation with the crosslinking
monomers (C) is generally that the glass transition temperatures
are higher by from 1.degree. C. to 10.degree. C. than those of the
corresponding non-crosslinked homo- or copolymers, and in a first
approximation here, the glass transition temperatures of the
microgels rise proportionally with the degree of crosslinking. In
the case of weakly crosslinked microgels, the glass transition
temperatures are higher by only about 1.degree. C. than for the
corresponding homo- or copolymers. In the case of highly
crosslinked microgels, the glass transition temperatures can be
higher by up to 10.degree. C. than the glass transition
temperatures of the corresponding non-crosslinked homo- or
copolymers. In a first approximation, the affect on T.sub.g of the
monomer (D) containing (a) hydroxy group(s) is negligible.
[0103] The glass transition temperatures of the gels produced by
the process are usually in the range from -78.degree. C. to
150.degree. C., preferably from -78.degree. C. to 125.degree.
C.
[0104] The gel content and the swelling index of the gel is
established via the amount of crosslinking monomer (C), and also
via the amount of regulator (which is described in more detail
below), the conversion in the polymerisation reaction and the
polymerisation temperature. Gel contents of from 10 to 100% by
weight can be achieved as a function of the selection and amount of
the crosslinking agent. However, preferred gel contents are above
70% by weight, particularly above 75% by weight, in particular
above 80% by weight.
[0105] The swelling indices of the resultant microgels are
generally below 30, preferably below 25, particularly preferably
below 20.
[0106] Content of hydroxy groups is determined by reacting acetic
anhydride with the dried microgels isolated from the latex, and
subsequent KOH titration of the resultant liberated acetic acid, to
DIN 53240. KOH consumption is equivalent to the hydroxy content of
the gels and is termed hydroxy number with dimension mg KOH/g of
polymer.
[0107] The hydroxy number of the resultant microgels is generally
from 0.5 to 200, in particular from 1 to 150, preferably from 5 to
100, in each case per g of dry microgel.
Activators
[0108] Suitable polymerisation initiators are compounds which
decompose to give free radicals. Among these are compounds which
contain an --O--O-- unit (peroxo compounds) or else an --N.dbd.N--
unit (azo compound). Among the peroxo compounds are hydrogen
peroxide, peroxodisulphates, peroxodiphosphates, perborates,
hydroperoxides, peracids, peresters and peroxides. Suitable
peroxodisulphates are sodium, potassium and ammonium
peroxodisulphate. Suitable hydroperoxides are tert-butyl
hydroperoxide, cumyl hydroperoxide and p-menthane hydroperoxide.
Suitable peroxides are benzoyl peroxide, 2,4-dichlorobenzoyl
peroxide, tert-butyl perbenzoate, dicumyl peroxide and
di-tert-butyl peroxide. Suitable azo compounds are
azobisisobutyronitrile, azobisvaleronitrile and
azobiscyclohexanenitrile.
[0109] Hydrogen peroxide, hydroperoxides, peracids, peresters,
peroxodisulphate, peroxodiphosphate and perborate can also be used
in combination with reducing agents, e.g. dithionite, sulphenates,
sulphinates, sulphoxylates, sulphite, metabisulphite, disulphite,
sugars, urea, thiourea, xanthogenates, thioxanthogenates,
hydrazinium salts and perthiocarbonate.
[0110] Activator systems obtained by combining an oxidant with a
reducing agent are termed redox systems. Catalysts also added to
these redox systems are salts of transition metal compounds, e.g.
iron, cobalt or nickel, in combination with suitable complexing
agents, such as sodium ethylenediammoniumtetraacetate, sodium
nitrilotriacetate, and also potassium diphosphate. The aim of using
the complexing agents is that the transition metal salt remains
dissolved even when the environment is alkaline. One preferred
redox system is composed of p-menthane hydroperoxide, sodium
formaldehyde-sulphoxylate, iron(II) sulphate and sodium
ethylenediaminoacetate.
[0111] The amount of polymerisation initiator is generally from
0.001 to 10 parts by weight, in particular from 0.5 to 10 parts by
weight, preferably from 1 to 6 parts by weight, based in each case
on 100 parts by weight of monomers used. The molar amount of
reducing agent is preferably from 50% to 500%, particularly
preferably from 60% to 400%, in particular from 70 to 300%, based
in each case on the molar amount of the oxidant used.
[0112] The molar amount of complexing agent is based on the amount
of transition metal used and can be up to ten times the equimolar
amount.
[0113] The reaction rate is controlled via the amount of the
polymerisation initiator.
[0114] In order to establish the desired reaction rate, it is
preferable to add all, or else some, of the components of the
initiator system in portions. It is preferable that 30% of the
reducing agent in combination with iron and with complexing agents,
together with 30% of the oxidant are added to the reactor at the
start of the polymerisation reaction. In this case, the remaining
amounts of reducing agent and of oxidants are added in portions or
continuously to the reaction mixture. It is possible to use the
rate of addition of the activator components to control the
reaction rate within certain limits.
Regulators
[0115] Examples of regulators that can be used are linear and
branched mercaptans, xanthogen disulphides, thioglycols, thiuram
disulphides, halogenated hydrocarbons and branched
hydrocarbons.
[0116] The mercaptans preferably have from 6 to 20 carbon
atoms.
[0117] Examples of suitable mercaptans are n-hexyl mercaptan,
n-dodecyl mercaptan, 2,4,4'-trimethylpentane-2-thiol,
2,2',4,6,6'-pentamethylheptane-4-thiol,
2,2',6,6'-tetramethylheptane-4-methanethiol and
2,2',4,6,6',8,8'-heptamethylnonane-4-thiol.
[0118] Examples of xanthogen disulphides are dimethylxanthogen
disulphide, diethylxanthogen disulphide and diisopropylxanthogen
disulphide.
[0119] Examples of thiuram disulphides are tetramethylthiuram
disulphide, tetraethylthiuram disulphide and tetrabutylthiuram
disulphide.
[0120] Examples of halogenated hydrocarbons are carbon
tetrachloride, ethyl bromide and methyl iodide.
[0121] Examples of branched hydrocarbons are those from which it is
easy to cleave an H radical, e.g. pentaphenylethane,
2,4-diphenyl-4-methyl-1-pentene, dipentene, and also terpenes, such
as .alpha.-terpene and .gamma.-terpene.
[0122] Preference is given to tert-dodecyl mercaptan mixtures based
on triisobutene and tetrapropene, these being available by way of
example from Lanxess Deutschland GmbH or from Chevron Phillips. If
regulator is used, its preferred amount is up to 2.50 parts by
weight, particularly up to 2.00 parts by weight, in particular up
to 1.00 part by weight, based in each case on 100 parts by weight
of the monomer mixture.
Conversion in the Polymerisation Reaction
[0123] The conversions obtained by the process of the invention in
the polymerisation reaction are generally from 65 to 100%,
preferably from 70 to 100%, particularly preferably from 80 to
100%. The high conversions in the polymerisation reaction are
advantageous for achieving the following objectives: [0124] 1. high
space/time yields of microgel; [0125] 2. reduction in thermal
stress in the removal of unconverted monomers by steam stripping;
and [0126] 3. establishment of high degrees of gel crosslinking,
with gel contents above 70% by weight and swelling indices smaller
than 30.
Other Constituents of a Polymerisation Mixture
Amount of Water
[0127] The amount of water used in the emulsion polymerisation
reaction is preferably from 150 to 900 parts by weight,
particularly preferably from 180 to 700 parts by weight, in
particular from 200 to 400 parts by weight, based in each case on
100 parts of the monomer mixture.
Salt Additions
[0128] In order to reduce viscosity during the polymerisation
reaction, salts of monovalent cations, such as sodium, potassium
and ammonium, can be added to the aqueous phase. The corresponding
anions can be mono- or divalent. Examples of the electrolytes used
are sodium chloride, potassium chloride, ammonium chloride, sodium
sulphate, potassium sulphate, ammonium sulphate, sodium nitrate,
potassium nitrate and ammonium nitrate. Potassium chloride is
preferred. The amount added of the salts is preferably from 0.01 to
1.0 part by weight, with preference from 0.05 to 0.25 part by
weight, based in each case on 100 parts by weight of the monomer
mixture.
Stoppers
[0129] It is generally possible to use hydroxylamine,
dialkylhydroxylamine and hydrazine, or else the salts derived
therefrom, to terminate the polymerisation reaction.
[0130] Specific examples of stoppers are hydroxyammonium sulphate,
diethylhydroxylamine, diisopropylhydroxylamine, and also
hydrazinium sulphate. Other terminators that can be used are sodium
dimethyldithiocarbamate, hydroxydithiocarboxylic salts,
hydroquinone, aromatic phenols, such as tert-butylpyrocatechol,
perthiocarbonate and phenothiazine. It is preferable to use
terminator agents which are nitrosamine-free and comprise no
constituents that can be nitrosated.
[0131] The amount added of the stopper is preferably from 0 to 2.5
parts by weight, particularly preferably from 0.05 to 2.00 parts by
weight, in particular from 0.10 to 0.50 part by weight, based in
each case on 100 parts by weight of monomer mixture.
[0132] However, since the gel is produced via polymerisation to
high conversions, and since the gels have high insoluble content,
and also low degrees of swelling in toluene, it is not absolutely
essential to terminate the polymerisation reaction, and termination
can also be omitted for the purposes of the present invention.
Removal of Residual Monomers after the Polymerisation Reaction
[0133] Once the polymerisation reaction has been concluded, the
resultant latex is steam-treated in order to remove unconverted
monomers and also volatile constituents. Temperatures used here are
preferably from 70 to 150.degree. C., and at temperatures below
100.degree. C. here, the pressure is reduced.
[0134] Prior to removal of the volatile constituents, emulsifier
can be used for post-stabilisation of the latex.
[0135] If an emulsifier is used for post-stabilisation, the rules
described above apply.
[0136] It is also possible to use the emulsifier system of the
invention as emulsifier for post-stabilisation.
[0137] The amounts used here of the abovementioned emulsifiers are
advantageously from 0 to 2.5% by weight, preferably from 0 to 1.5%
by weight, based in each case on the monomer mixture initially
used.
Addition of Antioxidants
[0138] Prior to or during coagulation of the latex, antioxidants
are added to the latex. Phenolic and aminic antioxidants are
suitable for this purpose. Suitable phenolic antioxidants are
alkylated phenols or else sterically hindered phenols, e.g.
2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol (BHT),
2,6-di-tert-butyl-4-ethylphenol, and also
2,2-methylenebis(4-methyl-6-tert-butylphenol) (BPH). Preference is
given to BHT and BPH.
[0139] If discoloration of the gels is not important, it is also
possible to use aminic antioxidants based on phenylenediamine.
Examples are N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD),
N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine (6PPD),
N-1,4-dimethylpentyl-N'-phenyl-p-phenylenediamine (7PPD) and
N,N'-bis-1,4-(1,4-dimethylpentyl)-p-phenylenediamine (77PD).
Preference is given to the aminic antioxidants mentioned. Aminic
antioxidants are preferably used when the hydroxy-modified gels are
used for the production of tyres.
[0140] The amount of antioxidants added is usually in the range
from 0.1 to 2.5% by weight.
Coagulation of the Latex
[0141] The latex is usually coagulated via electrolytes, which can
also be used in combination with polymeric precipitants. Given
compliance with the temperature criteria described at a later stage
below, it is easy to obtain crumb sizes greater than 5 mm when
coagulating the latex, by using salts of resin acids and of fatty
acids, without addition of any anionic, cationic or neutral
emulsifiers.
[0142] For the purposes of the present invention, electrolytes are
in particular acids and salts. Examples of acids that can be used
are hydrochloric acid, nitric acid, sulphuric acid, formic acid and
acetic acid.
[0143] Preference is given to sulphuric acid and acetic acid. Salts
used are the salts of mono-, di- and trivalent metals. The
corresponding anions of the salts are mono- and divalent. Examples
of the electrolytes used are sodium chloride, potassium chloride,
sodium sulphate, potassium sulphate, sodium nitrate, potassium
nitrate, sodium sulphate, potassium sulphate, magnesium chloride,
magnesium sulphate, calcium chloride, aluminum sulphate, and alums,
such as potassium aluminum sulphate or sodium aluminum sulphate.
Preference is given to sodium chloride, sodium sulphate, magnesium
chloride, magnesium sulphate, calcium chloride, aluminum sulphate
and alums, such as potassium aluminum sulphate or sodium aluminum
sulphate.
[0144] It is also possible to use combinations of acids and salts.
Preferred combinations are sodium chloride/sulphuric acid,
magnesium sulphate/sulphuric acid, calcium chloride/acetic acid,
potassium aluminum sulphate/sulphuric acid, and also aluminum
sulphate/sulphuric acid.
[0145] The amounts of electrolyte needed for coagulation of the
latex are generally from 0.1 to 100% by weight, preferably from 0.2
to 50% by weight, particularly preferably from 0.5 to 10% by
weight, of electrolyte, based in each case on the microgel.
[0146] Polymeric precipitants can be non-ionic, anionic, cationic,
or zwittterionic. They are not used alone, but rather in
combination with the abovementioned electrolytes.
[0147] Examples of non-ionic polymeric precipitants are
polyethylene oxide, ethylene oxide adducts onto
(alkyl)phenol/formaldehyde condensates, polyoxypropylene,
polyoxypropylene adducts onto (alkyl)phenol/formaldehyde
condensates, copolymeric adducts of ethylene and propylene oxide
onto (alkyl)phenol/formaldehyde condensates, and also onto fatty
acids, block copolymers based on polyethylene oxide and
polypropylene oxide, polyvinylpyrrolidone, cellulose derivatives,
as described in DE 2 332 096 A, DE 2 425 441 A and DE 2 751 786 A,
gelatine, fully or partially hydrolysed polyvinyl acetate, and also
polysaccharides, as described in DE 3 043 688 A.
[0148] Examples of anionic polymeric precipitants are the salts of
polyacrylic acids. Cationic polymeric precipitants are usually
based on poly(meth)acrylamide, or else on copolymers of
epichlorohydrin and of dialkylamines, such as dimethylamine, as
described in U.S. Pat. No. 4,920,176.
[0149] Preferred polymeric precipitants are block-copolymeric
adducts of ethylene oxide and propylene oxide onto
phenol/formaldehyde resins, where the cloud point of these is from
10 to 100.degree. C., preferably from 20 to 70.degree. C., as
described in EP 0 779 301 A, and also cellulose-based water-soluble
polymers.
[0150] The amounts of polymeric precipitants are from 0.01 to 5
parts by weight, preferably from 0.05 to 2 parts by weight, in each
case based on 100 parts by weight of the microgel.
[0151] Coagulation of the latex is carried out in the temperature
range from 10 to 150.degree. C., preferably at temperatures which
are above the glass transition temperature (T.sub.g) by from 10 to
20.degree. C. In order to produce adequately coarse crumb with
dimensions above 5 mm, the coagulation temperature should
preferably be higher than the glass transition temperature of the
microgel by at least 10.degree. C., with preference by at least
15.degree. C., particularly by at least 20.degree. C.
[0152] The amount of water used for the washing process is
generally from 0.5 to 50 parts by weight, preferably from 1 to 20
parts by weight, particularly preferably from 2 to 10 parts by
weight, in each case based on 100 parts by weight of microgel.
[0153] The wash water used can be either deionised or non-deionised
water. The temperature of the wash water is preferably identical to
the temperature used in the coagulation of the latex.
[0154] The wash process can be carried out continuously or
batchwise. It is preferable that the process used for washing the
crumb is one in which the wash is carried out continuously in a
countercurrent process.
Methods of Analysis
[0155] Shear stability is determined on the latex after termination
and after steam-treatment to remove residual monomers and other
volatile constituents. The latex comprises only the emulsifiers
used during the polymerisation reaction. The latex also has no
added antioxidants.
[0156] Two methods were used to determine latex stability:
1) Monitoring of latex diameter as a function of latex storage time
at room temperature. 2) Determination of shear stability as a
function of latex storage time at room temperature.
[0157] To determine shear stability, the latex was first filtered
through a filter with 50 .mu.m mesh width. The solids concentration
of the latex was then determined. For each determination of shear
stability, 80.+-.0.5 g of latex were added to a glass beaker with
internal diameter of 58 mm and height 144.5 mm, without any
adjustment of the pH or the solids concentration of the latex.
Shear was applied to the latex by means of an Ultraturrax T 18
Basic from IKA.RTM. Werke GmbH & Co. KG, using a serrated mixer
disc with diameter 16.9 mm. The distance between the lower edge of
the stirrer disc and the base of the beaker was 12.7.+-.3 mm. To
determine shear stability, the latex was exposed to rotation at 14
000.+-.200 rpm for 10 min at room temperature. The amount of
coagulate formed during the shear process was then determined. For
this, the latex was filtered through a filter with 50 .mu.m mesh
width. The coagulate removed by filtration was isolated and dried
to constant weight at 60.degree. C. in a vacuum oven. The amount of
coagulate was based on the amount of solids present in the latex
prior to exposure to shear. The following equations were used to
calculate the percentage amount of coagulate formed.
Amount of solids [ g ] = Amount of latex [ g ] .times.
Concentration of latex [ % by wt . ] 100 % ##EQU00002## Amount of
coagulate [ % ] = Amount of dry coagulate [ g ] Amount of solids [
g ] .times. 100 % ##EQU00002.2##
[0158] A latex has adequate shear stability if the amount of
coagulate formed during the said determination is smaller than 5%
by weight.
[0159] In the case of non-inventive latices of experimental series
(1) it is clear that the amount of coagulate formed during shear of
the latex correlates with the increase in particle size during
latex storage.
[0160] The diameter of the latex particles was determined as a
function of the latex storage time, on a filtered latex (sieve mesh
width: 50 .mu.m) by means of dynamic light scattering (DLS). A
Zetasizer.RTM. (Nano ZS) from Malvern Instruments Ltd.,
Worcestershire, England was used for the measurements. For each
measurement, a 1 ml plastics pipette was used to add one drop of
the latex to be studied to a measurement cell to which deionised
water had been charged. The resultant diluted latex was shaken two
or three times for homogenisation.
[0161] It was found that the diameter of the latex particles,
determined by dynamic light scattering, increases during storage of
the latex. During the course of the work it was apparent that a
latex has adequate stability while the diameter of the particles is
smaller than 100 nm. Latex stability is inadequate when particle
diameters are from 100 to 170 nm. Diameters above 170 nm were not
observed, since the latex had already undergone complete
coagulation. On the basis of these observations, if a latex is to
be resistant to shear and stable in storage, only a small change in
its particle size is permissible, as a function of standing time.
For achievement of adequate storage stability, particle diameter
must remain smaller than 100 nm even when the standing time of the
latex is more than 4 weeks.
[0162] To determine content of insoluble polymer fractions (gel
content) and swelling index, 250 mg of polymer are swollen in 25 ml
of toluene for 24 hours at 23.degree. C., with shaking. The
toluene-swollen (wet) gel (MG.sub.wet) is then isolated by
centrifuging at 20 000 rpm and weighed, and then dried to constant
weight at 70.degree. C. and again weighed (MG.sub.dry).
[0163] Gel content corresponds to the fraction insoluble in toluene
at 23.degree. C. It is calculated from the following formula:
Gel content [ % ] = MG dry 250 .times. 100 ##EQU00003##
[0164] Swelling index (SI) is calculated from the following
formula:
SI = MG wet MG dry ##EQU00004##
[0165] Gel content and swelling index depend in particular on the
nature and amount of the crosslinking monomer (C), on the amount of
regulator and on the conversion in the polymerisation reaction. Gel
content is preferably more than 70% by weight, particularly
preferably more than 75% by weight, in particular more than 80% by
weight. Swelling index is preferably less than 30, preferably less
than 25.
[0166] Glass transition temperature (T.sub.g) was determined by
means of DSC, using a Perkin-Elmer DSC-2. In the first measurement
cycle, the specimen is cooled by liquid nitrogen at 320 K/min to
-130.degree. C. and heated at a heating rate of 20 K/min to
150.degree. C. In the second measurement cycle, the specimen is
again cooled to -130.degree. C. and heated at 20 K/min. T.sub.g is
determined in the 2nd measurement cycle.
[0167] The glass transition temperatures (T.sub.g) of the microgels
are in a range which is generally from -78 to 150.degree. C.,
preferably from -78 to 120.degree. C., particularly preferably from
-75 to 125.degree. C.
EXAMPLES
Production of Microgels
[0168] The following starting materials were used to produce the
microgels (see experimental series (1) to (8)). All of the
formulation constituents in the tables here are based on 100 parts
by weight of the monomer mixture.
Monomers
[0169] .sup.1) Butadiene (99% purity, without stabiliser) from
Lanxess Deutschland GmbH [0170] .sup.2) Styrene (98% purity) from
KMF Labor Chemie Handels GmbH [0171] .sup.3) Trimethylolpropane
trimethacrylate (96% purity) from Aldrich; product number: 24684-0;
(abbreviation: TMPTMA) [0172] .sup.4) Hydroxyethyl methacrylate
(97% from Arcos; abbreviation: HEMA)
Emulsifiers
[0172] [0173] .sup.5) Disproportionated resin acid (abbreviated to
RA)--calculated as free acid based on the amount used of
Dresinate.RTM. 835 (Abieta Chemie GmbH; D-86358 Gersthofen)
[0174] The Dresinate.RTM. 835 batch used was characterized via
solids content and also via the emulsifier constituents present in
the form of sodium salt, in the form of free acid and in the form
of neutral material.
[0175] Solids content was determined to the specification published
by Maron, S. H.; Madow, B. P.; Borneman, E.: "The effective
equivalent weights of some rosin acids and soaps", Rubber Age,
April 1952, 71-72.
[0176] The average solids content value determined from three
aliquot specimens of the Dresinate.RTM. 835 batch used was 71% by
weight.
[0177] The emulsifier fractions present in the form of sodium salt
and in the form of free acid were determined titrimetrically by the
method described by Maron, S. H., Ulevitch, I. N., Elder, M. E.:
"Fatty and Rosin Acids, Soaps, and Their Mixtures, Analytical
Chemistry", Vol. 21, 6, 691-695.
[0178] For the determination (in one example), an excess of sodium
hydroxide solution (5 ml of 0.5N NaOH) was admixed with 1.213 g of
Dresinate.RTM. 835 (71% strength) in a mixture of 200 g of
distilled water and 200 g of distilled isopropanol, and the mixture
was back-titrated with 0.5N hydrochloric acid. The course of the
titration was followed by potentiometric pH measurement. The
titration curve was evaluated as described in Analytical Chemistry,
Vol. 21, 6, 691-695.
[0179] The average value obtained on three aliquot specimens of the
Dresinate.RTM. 835 batch used was: [0180] Total emulsifier content:
2.70 mmol/g.sub.dry weight [0181] Na salt: 2.42 mmol/g.sub.dry
weight [0182] Free acid: 0.28 mmol/g.sub.dry weight
[0183] The proportions by weight of Na salt, of free acid and of
unrecorded fractions of the Dresinate.RTM. 835 batch used were
calculated with the aid of the molar masses for the Na salt of
disproportionated abietic acid (324 g/mol), and the molar mass of
free disproportionated abietic acid (302 g/mol): [0184] Sodium salt
of disproportionated resin acid: 78.4% by weight [0185] Free
disproportionated resin acid: 8.5% by weight [0186] Unrecorded
fractions (neutral material): 13.1% by weight
[0187] In the following formulations, the amounts of Dresinate.RTM.
835 used in the polymerisation reactions have been converted by
calculation to free acid (abbreviated to RA) and stated as
proportions by weight, based on 100 parts by weight of monomers.
The neutral material has been ignored in this conversion
calculation.
[0188] For comprehension of the conversion of the amounts,
indicated in the table, of disproportionated abietic acid (RA) on
the basis of the amounts of Dresinate 835.RTM. used, the following
table is appended:
TABLE-US-00001 Starting weight of Calculated amount of
disproportionated Dresinate .RTM. 835 abietic acid (without neutral
material) [dry weight, g] [dry weight, g] 0.25 0.20 0.5 0.41 1.0
0.82 1.5 1.22 2.0 1.63 2.5 2.04 3.0 2.45 3.5 2.86 4.0 3.26 4.5 3.67
4.75 3.87 5.0 4.08
[0189] .sup.6) Partially hydrogenated tallow fatty
acid--abbreviated to FA (Edenor.RTM. HTiCT N from Cognis Oleo
Chemicals)
[0190] Total emulsifier content and the average molecular weight of
the batch of Edenor.RTM. HTiCT N used were determined
titrimetrically with the aid of the following methods: Maron, S.
H., Ulevitch, I. N., Elder, M. E.: "Fatty and Rosin Acids, Soaps,
and Their Mixtures, Analytical Chemistry", Vol. 21, 6, 691-695;
Maron, S. H.; Madow, B. P.; Borneman, E.: "The effective equivalent
weights of some rosin acids and soaps", Rubber Age (1952), 71-2).
In the titration process (in one example), an excess of 15 ml of
NaOH (0.5 mol/l) was admixed with 1.5 g of Edenor.RTM. HTiCT N in a
mixture of 200 g of distilled water and 200 g of distilled
isopropanol, and the mixture was back-titrated with 0.5N
hydrochloric acid.
[0191] The average value obtained here from three aliquot portions
of the batch of Edenor.RTM. HTiCT N used was: [0192] Total
emulsifier content: 3.637 mmol/g.sub.dry weight [0193] Molar mass
(free acid): 274.8 mg/mmol
[0194] In the following formulations, the amounts used of partially
hydrogenated tallow fatty acid (in the form commercially available)
have been stated in the form of "free acid=FA".
[0195] The amounts needed to achieve the degrees of neutralisation
stated in the tables were calculated on the basis of the amounts
determined titrimetrically of the various constituents of the
batches used of Dresinate.RTM. 835 and Edenor.RTM. HTiCT N. The
degrees of neutralisation in all of the examples of experimental
series (1) to (8) were achieved using potassium hydroxide.
Regulators
[0196] .sup.7) tert-Dodecyl mercaptan from Chevron Phillips
Chemical Company LP (Sulfole.RTM. 120) [0197] .sup.8) tert-Dodecyl
mercaptan from Lanxess Deutschland GmbH
[0198] The microgels were produced via emulsion polymerisation in a
201 autoclave with agitator. In the case of the polymerisation
mixtures described in experimental series (1), 2.15 kg of monomers
were used with 0.17 g of 4-methoxyphenol (Arcos Organics, Product
No. 126001000, 99%). In the case of the polymerisation mixtures
described in experimental series (2) to (8), 4.3 kg of monomers
were used in each case with 0.34 g of 4-methoxyphenol (Arcos
Organics, Product No. 126001000, 99%). The total amounts of
emulsifier and of water stated in the tables (after deducting the
amounts of water needed--see below--for producing the aqueous
premix solutions and p-menthane hydroperoxide solutions) were in
each case used as initial charge together with the emulsifiers and
with the amounts of potassium hydroxide needed to achieve the
degrees of neutralisation stated in Tables 1 to 8.
[0199] In the case of the polymerisation mixtures listed in
experimental series (1), once the reaction mixture had been heated
to 30.degree. C., in each case 50% of freshly produced aqueous
premix solutions (4% strength) were added to the autoclave. The
said premix solutions were composed of:
TABLE-US-00002 0.284 g of ethylenediaminetetraacetic acid (Fluka,
product number 03620), 0.238 g of iron(II) sulphate * 7H.sub.2O
(Riedel de Haen, product number 12354) (calculated without water of
crystallisation) 0.576 g of Rongalit C, Na
formaldehyde-sulphoxylate dihydrate (Merck-Schuchardt, product
number 8.06455) (calculated without water of crystallisation), and
0.874 g of trisodium phosphate * 12H.sub.2O (Acros, product number
206520010) (calculated without water of crystallisation).
[0200] For activation of the polymerisation reactions listed in
experimental series (1), a total amount of 1.4 g of p-menthane
hydroperoxide (Trigonox NT 50 from Akzo-Degussa) was used,
emulsified in 200 ml of the emulsifier solution produced in the
reactor. 50% of the said emulsion (0.7 g of Trigonox NT 50) was
used to initiate the polymerisation reaction.
[0201] On achievement of 30% conversion, the remaining 50% of the
premix solution, and also of the p-menthane hydroperoxide emulsion,
were metered in.
[0202] In the case of experimental series (2) to (8), the amount
added of the said components to the reactor, both at the beginning
of the polymerisation reaction and on achievement of 30% conversion
in the polymerisation reaction, was twice that in experimental
series (1).
[0203] The temperature profile during the polymerisation reaction
was achieved by adjusting the amount of coolant and the temperature
of the coolant within the temperature ranges stated in the
tables.
[0204] Once the conversion achieved in the polymerisation reaction
was more than 85% (usually: from 90% to 100%), the polymerisation
reaction was terminated by adding an aqueous solution of 2.35 g of
diethylhydroxylamine (DEHA, Aldrich, product number 03620).
Removal of Volatile Constituents
[0205] The latex was subjected to steam distillation at atmospheric
pressure in order to remove volatile constituents.
[0206] Prior to coagulation of the latex, a 50% strength dispersion
of Vulkanox.RTM. KB (1.25% by weight of Vulkanox.RTM. KB, based on
solids) was added as antioxidant to the latex. The Vulkanox.RTM. KB
dispersion was composed of:
TABLE-US-00003 360 g of deionised water (DW) 40 g of alkylphenol
polyglycol ether (NP10 emulsifier from Lanxess Deutschland GmbH)
400 g of Vulkanox .RTM. KB from Lanxess Deutschland GmbH The
Vulkanox .RTM. KB dispersion was produced with the aid of an
Ultraturrax at from 95 to 98.degree. C.
Coagulation and Work-Up of the Latex
[0207] The latices of experimental series (1) to (8) were
coagulated batchwise in an open 55 L tank with basal valve, with
facilities for heating and stirring. In each case, coagulation of
the latex used 16 L of latex with the solids concentrations stated
in the tables and 15 L of precipitant liquor. The precipitant
liquor was composed of deionised water in which the amount of
dissolved calcium chloride was sufficient to give an amount of
1.77% by weight of calcium chloride, based on microgel (solids) in
each coagulation of the latex. The coagulation of the latex was
achieved by adding the latex, with stirring, to the heated
precipitant solution. Once the latex had been added, the cooled
contents of the tank were heated to the temperature of the
precipitant prior to latex addition, and maintained at the said
temperature until the serum became clear (from 10 to 15 min).
[0208] The temperature to which the precipitant solution was heated
prior to latex addition depended on the glass transition
temperature of the microgel. In the experiments where the glass
transition temperature of the microgel was <0.degree. C., it was
sufficient to heat the precipitant solution to 50.degree. C. in
order to obtain adequately coarse microgel crumb with a diameter of
about 5 mm.
[0209] In experimental series (5) to (8), and also in experiment 16
(series 3), latices with microgel glass transition temperatures
>0.degree. C. were obtained. In order to obtain crumb with
diameters >5 mm during coagulation of these microgel latices,
the precipitant solution had to be heated to a temperature which
was above the corresponding glass transition temperature of the
microgel by .gtoreq.15.degree. C., before the corresponding
microgel latex was added to the precipitant solution.
[0210] In the case of coagulation of the latex (T.sub.g=62.degree.
C.) resulting from experiment 16* (experimental series 3) with
aqueous calcium chloride solution, the crumb obtained at 60.degree.
C. and 70.degree. C. had an inadequate size smaller than 2 mm. At
75.degree. C., crumb size was in the range from 2 to 5 mm. At
coagulation temperature 80.+-.2.degree. C., crumb size was greater
than 5 mm.
[0211] In the case of coagulation of the latex
(T.sub.g=103.5.degree. C.) resulting from experiment 49*
(experimental series 8) with aqueous calcium chloride solution, the
only product obtained at precipitant-liquor temperatures from 95 to
98.degree. C. was crumb with inadequate size of up to 2 mm.
[0212] After clarification of the serum, 20 L of deionised water
were admixed with the dispersion of the crumb, and the mixture was
allowed to stand, without stirring. After from 15 to 30 minutes,
the dispersion of the crumb formed a cream (except in the case of
experiment 49*). The serum was discharged by way of a basal valve.
The crumb remaining in the tank was then slurried with 40 L of
deionised water (25.degree. C.), with stirring. Once the cream had
formed, the crumb was separated from the wash water by using a
sieve with mesh width of 2 mm, subjected to preliminary mechanical
dewatering to give a residual moisture level of from 20 to 30%, and
dried batchwise in a vacuum oven at 70.degree. C. in a stream of
air to give a residual moisture level of .ltoreq.0.5% by
weight.
[0213] Coagulation of the latex of experiment 49* gave crumb which
after addition of 20 L of deionised water, in contrast to the other
experiments, did not form a cream but instead formed a sediment. In
this experiment, the supernatant latex serum was withdrawn. The
wash took place as in the other experiments via slurrying with 40 L
of deionised water at 25.degree. C. A 2 mm sieve was used to
isolate the crumb from the wash water. The further work-up of the
crumb was as described above.
[0214] The following indices are used in the tables below: [0215]
.sup.1) Butadiene (unstabilised) [0216] .sup.2) Styrene (stabilised
with from 100 to 150 ppm of 4-tert-butylpyrocatechol) [0217]
.sup.3) Trimethylolpropane trimethacrylate (96% purity from
Aldrich) [0218] .sup.4) Hydroxyethyl methacrylate (97% purity from
Areas) [0219] .sup.5) Amount of disproportionated resin acid
(abbreviated to RA) calculated from the amount of Dresinate 835
used [0220] .sup.6) Edenor HTiCT N from Oleo Chemicals (abbreviated
to FA) [0221] .sup.7) tert-Dodecyl mercaptan (Sulfole.RTM. 120 from
Chevron Phillips) [0222] .sup.8) tert-Dodecyl mercaptan (Lanxess
Deutschland GmbH)
[0223] Examples according to the invention have been denoted with
"*" below.
Experimental Series (1)
Effect of Amount of HEMA on Latex Storage Time (Comparative
Examples not According to the Invention)
TABLE-US-00004 [0224] Emulsifiers Monomers [phm] Polymeri- [parts
by weight] Degree of Polymerisation sation Con- Buta- Sty- RA/ RA +
neutralisation Water temperature time version Product diene.sup.1)
rene.sup.2) TMPTM.sup.3) HEMA.sup.4) RA.sup.5) FA.sup.6) FA FA [%]
[phm] [.degree. C.] [min] [%] 1 44.5 54 1.5 0 3.87 0.22 17.59 4.09
114 400 30-36 330 100 2 45.5 45.5 1.5 7.5 3.87 0.22 17.59 4.09 114
400 30-34 360 90.5 3 46.0 42.5 1.5 10 3.87 0.22 17.59 4.09 114 400
30-34 370 90.5
Results:
TABLE-US-00005 [0225] Solids content pH of Amount of coagulate on
exposure (after latex Acid OH Particle diameter to shear [% by
weight] monomer (after Gel number number [nm] as a function as a
function of removal) monomer content S [mg KOH/g of T.sub.g of
storage time in weeks storage time in weeks Product [% by wt.]
removal) [% by wt.] Index microgel] [.degree. C.] 0 3 6 8 12 0 3 6
8 12 1 20.0 11.1 63.3 11.7 6.2 7.7 -22.5 65 67 66 65 63 0.25 0.22
0.55 0.75 1.0 2 18.6 7.6 92.1 7.9 5.4 25.0 -14.5 65 105 136 166
coag. 0.42 5.0 6.8 19.8 coag. 3 18.6 7.9 94.2 10.9 6.2 32.6 -15.5
73 120 218 coag. coag. 0.27 15.4 coag. coag. coag.
[0226] In experimental series (1), the comparative examples not
according to the invention show that, unlike in the HEMA-free
reference experiment 1, when the amounts used of HEMA are more than
5 parts by weight (based on the composition of the monomer) the
resultant latex storage times (experiments 2 and 3) are inadequate
(less than 3 weeks) when the polymerisation reaction is carried out
at temperatures above 30.degree. C. to conversions of more than 90%
in polymerisation times of less than 7 hours, and the
polymerisation reaction uses disproportionated resin acid and
partially hydrogenated tallow fatty acid in a ratio of 17.6/1 by
weight with a degree of neutralisation of 114%.
Experimental Series (2)
Effect of Degree of Neutralisation of Resin Acid and of Fatty Acid
on Latex Stability (Examples According to the Invention: 5*, 6*, 7*
and 8*)
TABLE-US-00006 [0227] Monomers Emulsifiers [phm] Polymeri-
Polymeri- [parts by weight] Degree of sation sation Con- Buta- Sty-
RA/ RA + neutralisation Water temperature time version Product
diene.sup.1) rene.sup.2) TMPTM.sup.3) HEMA.sup.4) RA.sup.5)
FA.sup.6) FA FA [%] [phm] [.degree. C.] [min] [%] 4 38 53 1.5 7.5
3.67 0.44 8.34 4.11 103 200 30-34 475 85.6 5* 38 53 1.5 7.5 3.67
0.44 8.34 4.11 106 200 30-34 330 92.0 6* 38 53 1.5 7.5 3.67 0.44
8.34 4.11 114 200 30-33 420 90.5 7* 38 53 1.5 7.5 3.67 0.44 8.34
4.11 123 200 30-32 360 92.0 8* 38 53 1.5 7.5 3.67 0.44 8.34 4.11
145 200 30-32 405 91.7 9 38 53 1.5 7.5 3.67 0.44 8.34 4.11 168 200
30-32 360 88.6
Results:
TABLE-US-00007 [0228] Solids content (after pH of latex Acid OH
monomer (after Gel number number Particle diameter in [nm] as a
function removal) monomer content S [mg KOH/g of T.sub.g of storage
time in weeks Product [% by wt.] removal) [% by wt.] Index
microgel] [.degree. C.] 0 1 3 4 6 8 4 29.1 7.9 94 12.6 6.9 21.4 -3
89 91 96 122 138 152 5* 29.0 8.2 91.2 10.3 4.9 24.9 -4.5 71 73 77
82 104 138 6* 29.2 8.1 94.3 13.3 5.1 19.5 -5 85 82 85 92 105 122 7*
34.0 8.2 94.7 11.5 4.9 19.3 -.5 79 79 82 96 112 118 8* 32.0 8.4
94.6 14.0 5.4 19.4 -5 83 83 91 98 124 138 9 30.3 8.4 95.2 11.9 6.0
20.6 -5 85 86 107 127 152 163
[0229] In experimental series (2), examples 5*, 6*, 7* and 8*
according to the invention (denoted with "*") show that the
resultant latex storage times are greater than 4 weeks if the ratio
of disproportionated resin acid to partially hydrogenated fatty
acid is 8.34/1 and the degree of neutralisation of resin acid and
of fatty acid is from 106% to 145%. If the degree of neutralisation
of resin acids and of fatty acids is <104% or >165%,
inadequate latex stabilities are obtained.
Experimental Series (3)
Effect of Amount of Mercaptan on Stability of the Latex During
Storage (Examples According to the Invention)
TABLE-US-00008 [0230] Emulsifiers [phm] Monomers Degree of
Polymeri- Polymeri- tert-DDM [parts by weight] neutral- sation
sation Con- [phm] Buta- Sty- RA/ RA + isation Water temperature
time version Product .sup.7) .sup.8) diene.sup.1) rene.sup.2)
TMPTM.sup.3) HEMA.sup.4) RA.sup.5) FA.sup.6) FA FA [%] [phm]
[.degree. C.] [min] [%] 10* -- -- 91 -- 1.5 7.5 3.67 0.44 8.34 4.11
123 300 30-32 360 97 11* 0.10 -- 91 -- 1.5 7.5 3.67 0.44 8.34 4.11
123 300 30-32 300 100 12* -- 0.20 91 -- 1.5 7.5 3.67 0.44 8.34 4.11
123 300 30-32 300 95.5 13* 0.25 -- 44.5 46.5 1.5 7.5 3.67 0.44 8.34
4.11 123 400 30-35 240 97 14* -- 0.5 44.5 46.5 1.5 7.5 3.67 0.44
8.34 4.11 123 400 30-38 220 98 15* 0.85 -- 44.5 46.5 1.5 7.5 3.67
0.44 8.34 4.11 123 400 30-40 200 96 16* 0.85 -- 10.5 80.5 4 5 3.67
0.44 8.34 4.11 123 400 30-35 180 95
Results:
TABLE-US-00009 [0231] Solids content (after pH of latex Acid OH
monomer (after Gel number number Particle diameter in [nm] as a
function removal) monomer content S [mg KOH/g of T.sub.g of latex
storage time in weeks Product [% by wt.] removal) [% by wt.] Index
microgel] [.degree. C.] 0 2 4 6 8 12 10* 25.0 8.0 96.2 7.9 6.8 27.7
-78 65 65 68 89 121 160 11* 26.4 7.7 96.1 9.6 6.3 25.8 -79 62 61 60
68 86 123 12* 25.2 8.5 95.2 13.2 7.1 28.5 -79 56 55 66 94 107 121
13* 17.0 7.8 92 14.8 3.3 20.6 -13 47 52 69 88 98 112 14* 18.0 7.4
88 22.5 3.4 26.3 -11.5 51 54 76 84 91 96 15* 18.0 7.4 78 24.7 6.5
25.9 -15 50 51 55 63 75 130 16* 17.8 7.5 96 11.3 7.5 20.0 62 47 49
65 81 88 93
[0232] In experimental series (3), the examples according to the
invention show that the maximum latex storage times are almost
independent of the nature and amount of the mercaptan used, given
compliance with the following: the ranges according to the
invention for the total amount of disproportionated resin acid and
of partially hydrogenated fatty acid (4.11 parts by weight per 100
parts by weight of monomer), the ratio by weight of
disproportionated resin acid to partially hydrogenated fatty acid
(83/1) and the degree of neutralisation of the disproportionated
resin acid and partially hydrogenated fatty acid (123%).
Experimental Series (4)
Effect of Ratio by Weight of Resin Acid and Fatty Acid on Latex
Stability (Examples According to the Invention: 17*, 18*, 19*, 20*,
21*, 22* and 23*)
TABLE-US-00010 [0233] Monomers Emulsifiers [phm] Polymeri-
Polymeri- [parts by weight] Degree of sation sation Con- Buta- RA/
RA+ neutralisation Water temperature time version Product
diene.sup.1) TMPTM.sup.3) HEMA.sup.4) RA.sup.5) FA.sup.6) FA FA [%]
[phm] [.degree. C.] [min] [%] 17* 91 1.5 7.5 4.08 0 -- 4.08 122 300
30-34 420 97.1 18* 91 1.5 7.5 3.67 0.44 8.34 4.11 123 300 30-32 345
92.5 19* 91 1.5 7.5 3.26 0.88 3.70 4.14 124 300 30-32 300 99.0 20*
91 1.5 7.5 2.86 1.32 2.17 4.18 125 300 30-32 300 100 21* 91 1.5 7.5
2.45 1.76 1.39 4.21 126 300 30-32 300 98.0 22* 91 1.5 7.5 2.04 2.20
0.93 4.24 126 300 30-32 300 96.0 23* 91 1.5 7.5 0 2.20 -- 2.20 128
300 30-32 300 95.5
Results:
TABLE-US-00011 [0234] Solids content (after pH of latex Acid OH
monomer (after Gel number number Particle diameter in [nm] as a
function removal) monomer content S [mg KOH/g of T.sub.g of latex
storage time in weeks Product [% by wt.] removal) [% by wt.] Index
microgel] [.degree. C.] 0 2 4 6 8 12 17* 23.9 8.2 95.3 8.3 7.6 25.1
-78 78 79 82 100 111 135 18* 22.8 8.2 96.2 8.5 7.2 32.0 -78.5 58 56
64 80 101 140 19* 25.4 8.0 96.7 8.2 6.0 28.1 -79 53 55 59 77 95 123
20* 25.1 8.0 96.9 9.2 6.1 29.1 -78.5 53 55 63 79 96 114 21* 24.0
7.8 97.0 7.7 5.8 30.3 -79 50 56 57 71 83 106 22* 23.6 8.0 97.4 8.8
6.0 32.1 -78 54 48 53 72 88 104 23* 22.7 7.9 98.4 10.4 2.9 28.1 -79
53 63 84 108 123 144
[0235] In experimental series (4), examples 17*, 18*, 19*, 20*,
21*, 22* and 23* according to the invention show that the resultant
latex storage times are more than 6 weeks if the entirety of the
resin acids and fatty acids is .gtoreq.2.20 parts by weight.
Experimental Series (5)
Effect of Degree of Neutralisation of Resin Acid and of Fatty Acid
on Latex Stability (Examples According to the Invention)
TABLE-US-00012 [0236] Monomers Emulsifiers [phm] Polymeri-
Polymeri- [parts by weight] Degree of sation sation Con- Buta- Sty-
RA/ RA + neutralisation Water temperature time version Product
diene.sup.1) rene.sup.2) TMPTM.sup.3) HEMA.sup.4) RA.sup.5)
FA.sup.6) FA FA [%] [phm] [.degree. C.] [min] [%] 24* 21 70 1.5 7.5
2.45 1.76 1.39 4.21 112 300 30-34 300 96 25* 21 70 1.5 7.5 2.45
1.76 1.39 4.21 116 300 30-32 300 97 26* 21 70 1.5 7.5 2.45 1.76
1.39 4.21 119 300 30-33 300 100 27* 21 70 1.5 7.5 2.45 1.76 1.39
4.21 123 300 30-36 200 99 28* 21 70 1.5 7.5 2.45 1.76 1.39 4.21 126
300 30-39 150 96 29* 21 70 1.5 7.5 2.45 1.76 1.39 4.21 129 300
30-31 360 96 30* 21 70 1.5 7.5 2.45 1.76 1.39 4.21 132 300 30-32
300 96 31* 21 70 1.5 7.5 2.45 1.76 1.39 4.21 136 300 30-45 120 100
32* 21 70 1.5 7.5 2.45 1.76 1.39 4.21 139 300 30-31 300 98
Results:
TABLE-US-00013 [0237] Solids content (after pH of latex Acid OH
monomer (after Gel number number Particle diameter in [nm] as a
function removal) monomer content S [mg KOH/g of T.sub.g of latex
storage time in weeks Product [% by wt.] removal) [% by wt.] Index
microgel] [.degree. C.] 0 2 4 8 8 12 24* 27.4 8.4 96.0 8.3 6.8 29.3
36.0 54 54 53 53 54 58 25* 28.1 8.4 96.1 8.2 6.8 25.9 34.5 54 53 54
57 57 63 26* 26.9 8.4 96.3 8.0 5.7 27.4 32.0 53 53 53 56 56 59 27*
26.4 8.5 96.5 8.1 5.8 26.5 34.5 51 52 54 54 55 57 28* 26.7 8.7 96.4
8.1 6.5 27.1 39.0 50 52 53 53 54 54 29* 26.5 8.5 96.4 7.9 7.0 25.2
37.5 57 59 61 59 60 66 30* 24.3 8.4 95.8 8.8 6.4 26.2 35.5 52 53 55
55 53 59 31* 26.3 8.2 96.3 8.4 6.2 26.2 29.0 56 58 53 53 62 62 32*
24.5 8.3 97.0 8.1 6.1 25.7 39.0 59 60 55 53 61 64
[0238] In experimental series (5), the examples according to the
invention show that the resultant latices have adequate stability
of more than 12 weeks if the degrees of neutralisation of the
disproportionated resin acid and of the partially hydrogenated
fatty acid are from 112 to 139%.
Experimental Series (6)
Effect of Amount of Emulsifier (Total Amount of Resin Acid and of
Fatty Acid) on Latex Stability (examples according to the
invention: 34*, 35*, 36*, 37*, 38* and 39*)
TABLE-US-00014 [0239] Monomers Emulsifiers [phm] Polymeri-
Polymeri- [parts by weight] Degree of sation sation Con- Buta- Sty-
RA/ RA + neutralisation Water temperature time version Product
diene.sup.1) rene.sup.2) TMPTM.sup.3) HEMA.sup.4) RA.sup.5)
FA.sup.6) FA FA [%] [phm] [.degree. C.] [min] [%] 33 21 70 1.5 7.5
1.22 0.88 1.39 2.10 120 300 30-34 300 95 34* 21 70 1.5 7.5 1.63
1.17 1.39 2.80 120 300 30-32 300 99 35* 21 70 1.5 7.5 2.04 1.47
1.39 3.51 120 300 30-32 330 96 36* 21 70 1.5 7.5 2.45 1.76 1.39
4.21 120 300 30-32 300 97 37* 21 70 1.5 7.5 2.86 1.98 1.44 4.84 120
300 30-32 300 99 38* 21 70 1.5 7.5 3.26 2.34 1.39 5.60 120 300
30-32 300 95 39* 21 70 1.5 7.5 3.67 2.63 1.39 6.30 120 300 30-32
300 96
Results:
TABLE-US-00015 [0240] Solids content (after pH of latex Acid OH
monomer (after Gel number number Particle diameter in [nm] as a
function removal) monomer content S [mg KOH/g of T.sub.g of latex
storage time in weeks Product [% by wt.] removal) [% by wt.] Index
microgel] [.degree. C.] 0 2 4 6 8 12 33 24.0 7.5 97.3 7.6 4.7 30.8
42 67 87 120 coag. coag. coag. 34* 25.3 7.0 96.8 8.1 6.4 30.0 39 56
57 70 99 coag. coag. 35* 25.1 8.0 96.4 7.9 6.2 29.7 40 53 52 61 56
59 64 37* 26.4 8.3 96.1 8.2 7.2 30.8 37.5 51 51 58 55 53 53 37*
25.1 8.5 96.3 8.0 7.5 28.7 36.5 56 54 62 58 54 57 38* 25.3 8.7 96.0
8.1 8.8 30.8 41.5 54 61 56 52 54 56 39* 23.7 8.8 95.9 8.3 8.6 31.4
43.5 53 58 53 52 53 55
[0241] In experimental series (6), examples 34*, 35*, 36*, 37*, 38*
and 39* according to the invention show that the resultant latices
are stable with latex storage times of more than 6 weeks if the
total amount composed of disproportionated resin acid and of
partially hydrogenated fatty acid is .gtoreq.2.20 parts by weight,
based on 100 parts by weight of the monomer mixture.
Experimental Series (7)
Effect of Ratio by Weight of Resin Acid to Fatty Acid on Latex
Stability (Examples According to the Invention)
TABLE-US-00016 [0242] Monomers Emulsifiers [phm] Polymeri-
Polymeri- [parts by weight] Degree of sation sation Con- Buta- Sty-
RA/ RA + neutralisation Water temperature time version Product
diene.sup.1) rene.sup.2) TMPTM.sup.3) HEMA.sup.4) RA.sup.5)
FA.sup.6) FA FA [%] [phm] [.degree. C.] [min] [%] 40* 21 70 1.5 7.5
0.20 2.42 0.08 2.62 120 300 30-32 300 100 41* 21 70 1.5 7.5 0.41
2.20 0.19 2.61 120 300 30-32 300 95 42* 21 70 1.5 7.5 0.61 1.98
0.31 2.59 120 300 30-32 300 98 43* 21 70 1.5 7.5 0.82 1.76 0.47
2.58 120 300 30-32 300 97 44* 21 70 1.5 7.5 1.02 1.54 0.66 2.56 120
300 30-32 300 100 45* 21 70 1.5 7.5 1.22 1.32 0.92 2.54 120 300
30-32 335 95
Results:
TABLE-US-00017 [0243] Solids content (after pH of latex Acid OH
monomer (after Gel number number Particle diameter in [nm] as a
function removal) monomer content S [mg KOH/g of T.sub.g of storage
time in weeks Product [% by wt.] removal) [% by wt.] Index
microgel] [.degree. C.] 0 2 4 6 8 12 40* 27.1 7.8 93.0 8.4 4.3 28.2
37.0 51 56 60 85 95 135 41* 23.9 7.9 70.3 7.6 4.4 31.4 42.0 60 59
57 60 61 67 42* 25.1 7.8 73.8 8.2 4.3 29.8 37.0 52 53 67 70 83 115
43* 25.1 8.0 73.5 7.5 4.8 30.4 37.5 54 60 59 57 58 62 44* 25.3 7.6
74.0 7.7 4.1 27.3 35.5 59 57 69 73 84 97 45* 24.6 7.9 71.2 7.6 3.8
30.4 42.0 61 61 62 63 76 coag.
[0244] In experimental series (7), examples 40* to 45* according to
the invention show that the latices obtained are stable with latex
storage times of more than 6 weeks if the ratio by weight of resin
acid to fatty acid is greater than 0.08/1.
Experimental Series (8)
Storage-Stable Microgel Latices with Different Glass Transition
Temperature
TABLE-US-00018 [0245] Monomers Emulsifiers [phm] Polymeri-
Polymeri- [parts by weight] Degree of sation sation Con- Buta- Sty-
RA/ RA + neutralisation Water temperature time version Product
diene.sup.1) rene.sup.2) TMPTM.sup.3) HEMA.sup.4) RA.sup.5)
FA.sup.6) FA FA [%] [phm] [.degree. C.] [min] [%] 46* 45.13 43.37 4
7.5 2.45 1.76 1.39 4.21 120 300 15 360 96 47* 61.95 26.55 4 7.5
2.45 1.76 1.39 4.21 120 300 15 300 93 48* 7.00 80.5 5 7.5 2.45 1.76
1.39 4.21 120 300 30 300 96 49* -- 91 1.5 7.5 2.45 1.76 1.39 4.21
120 200 30-70 60 96 50* 52 42.5 2.5 3.0 2.45 1.76 1.39 4.21 120 300
30 320 95 51* 46.5 31.0 12.5 10 2.45 1.76 1.39 4.21 120 200 30-70
350 94 52* 51.6 34.4 12.5 1.5 2.45 1.76 1.39 4.21 120 200 30-70 320
96
Results:
TABLE-US-00019 [0246] Solids content (after pH of latex Acid OH
monomer (after Gel number number Particle diameter in [nm] as a
function removal) monomer content S [mg KOH/g of T.sub.g of storage
time in weeks Product [% by wt.] removal) [%] Index microgel]
[.degree. C.] 0 2 4 6 8 12 46* 25.0 8.5 95.7 8.1 6.1 33.5 -5 49 46
48 51 57 66 47* 23.5 8.5 91.7 7.2 6.5 37.6 -35.5 43 40 47 49 53 76
48* 25.0 8.1 92.5 5.4 6.5 30.4 +83.5 60 62 64 60 62 63 49* 30.0 8.2
91.6 7.5 6.6 29.1 +103.5 58 60 57 59 59 61 50* 24.8 8.4 93.0 9.5
6.5 14.5 -21.5 60 63 62 61 65 69 51* 25.1 8.3 9.7 4.4 5.6 46.7 -5
55 58 61 64 71 88 52* 24.9 8.5 95 4.9 5.3 5.1 -20 60 61 58 63 63
65
[0247] In experimental series (8), the examples according to the
invention show that, given an ideal resin/fatty acid ratio of
1.39/1 and given an ideal degree of neutralisation of 120%, it is
possible to produce storage-stable hydroxy-modified microgel
latices with glass transition temperatures in the range from
-5.degree. C. to +103.5.degree. C. and with hydroxy numbers in the
range from 5.1 to 46.7 mg KOH/g of microgel.
[0248] The result found from experimental series (1) to (8) is
that, to produce storage-stable microgel latices containing hydroxy
groups simultaneous compliance with the following parameters is
necessary during the emulsion polymerisation reaction: [0249] 1)
ratio by weight of disproportionated resin acid to partially
hydrogenated fatty acid: from 1/15 to 15/1, preferably from 1/12 to
12/1 [0250] 2) total of weights of disproportionated resin acid and
of partially hydrogenated fatty acid: >2.2 parts by weight,
preferably >2.5 parts by weight, based on 100 parts by weight of
the entire monomer mixture [0251] 3) degree of neutralisation of
disproportionated resin acid and of partially hydrogenated fatty
acid: from 104 to 165%, preferably from 105 to 160%
[0252] In order to achieve adequately large crumb with diameters
>5 mm in the coagulation of the microgel latices produced
according to the invention, it was essential that the temperatures
used during coagulation of the latex are higher than the glass
transition temperatures of the corresponding microgels by
15.degree. C.
[0253] The present invention has been described with reference to
specific details of particular embodiments thereof. It is not
intended that such details be regarded as limitations upon the
scope of the invention except insofar as and to the extent that
they are included in the accompanying claims.
[0254] As used in this specification and the appended claims, the
singular forms "a," "an," and "the" include plural referents unless
the content clearly dictates otherwise.
* * * * *