U.S. patent application number 09/729933 was filed with the patent office on 2001-09-27 for polyvinyl alcohol-stabilized 1,3-diene/ (meth)acrylate copolymers.
This patent application is currently assigned to Wacker Polymer Systems GmbH & Co. KG. Invention is credited to Harzschel, Reinhard, Mayer, Theo.
Application Number | 20010025078 09/729933 |
Document ID | / |
Family ID | 7934203 |
Filed Date | 2001-09-27 |
United States Patent
Application |
20010025078 |
Kind Code |
A1 |
Mayer, Theo ; et
al. |
September 27, 2001 |
Polyvinyl alcohol-stabilized 1,3-diene/ (meth)acrylate
copolymers
Abstract
The invention discloses polyvinyl alcohol-stabilized copolymers
of 1,3-dienes with methacrylates and/or acrylates in the form of
their aqueous polymer dispersions or polymer powders redispersible
in water, and to a process for their preparation and their use.
Inventors: |
Mayer, Theo; (Julbach,
DE) ; Harzschel, Reinhard; (Burghausen, DE) |
Correspondence
Address: |
William G. Conger
BROOKS & KUSHMAN P.C.
1000 Town Center
Twenty-Second Floor
Southfield
MI
48075
US
|
Assignee: |
Wacker Polymer Systems GmbH &
Co. KG
|
Family ID: |
7934203 |
Appl. No.: |
09/729933 |
Filed: |
December 5, 2000 |
Current U.S.
Class: |
524/459 ;
524/423; 524/425; 524/458; 524/460 |
Current CPC
Class: |
C08F 236/04 20130101;
C04B 26/06 20130101; C04B 2111/1006 20130101; C04B 40/0028
20130101; C08F 236/04 20130101; C04B 24/26 20130101; C08F 2/30
20130101; C04B 24/2641 20130101; C08F 220/12 20130101; C04B 40/0028
20130101; C04B 24/2623 20130101 |
Class at
Publication: |
524/459 ;
524/423; 524/425; 524/458; 524/460 |
International
Class: |
C08L 009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 23, 1999 |
DE |
199 62 568.9 |
Claims
We claim:
1. An emulsifier- and solvent-free copolymer, stabilized with
nonionic polyvinyl alcohol as a protective colloid, of a 1,3-diene
with a methacrylate and/or acrylate in the form of its aqueous
polymer dispersion or polymer powder redispersible in water,
obtainable by emulsion polymerization and optionally drying of the
polymer dispersion obtainable thereby, from 10 to 100% by weight of
the amount of polyvinyl alcohol being initially introduced before
the initiation of the polymerization and the remaining amount being
metered in during polymerization, and the addition of the polyvinyl
alcohol and of the comonomers being controlled in such a way that,
during the polymerization, the amount of protective colloid is
always from 1 to 70% by weight of the total amount of free
comonomers.
2. A process for the preparation of emulsifier- and solvent-free
copolymers, stabilized with polyvinyl alcohol as a protective
colloid, of a 1,3-diene with a methacrylate and/or acrylate in the
form of their aqueous polymer dispersions or polymer powders
redispersible in water, by emulsion polymerization of a mixture
containing one or more comonomers from the group consisting of the
1,3-dienes and at least one comonomer selected from the group
consisting of the methacrylates and acrylates, in the presence of
from 1 to 15% by weight, based on the total weight of the monomers,
of at least one polyvinyl alcohols and optionally drying of the
polymer dispersions obtainable thereby, from 10 to 100% by weight
of the amount of polyvinyl alcohol being initially introduced
before the initiation of the polymerization and the remaining
amount being metered in during polymerization, and the addition of
polyvinyl alcohol and of the comonomers being controlled in such a
way that, during the polymerization, the amount of protective
colloid is always from 1 to 70% by weight of the total amount of
free comonomers.
3. The process as claimed in claim 2, wherein mixtures comprising
from 20 to 80% by weight of (meth)acrylates and from 80 to 20% by
weight of 1,3-diene are polymerized, it being possible for the
mixtures optionally also to contain one or more of the
above-mentioned auxiliary monomers in the stated amounts, and the
amounts in % by weight summing to 100% by weight.
4. The process as claimed in claim 2, wherein the 1,3-diene
polymerized is 1,3-butadiene or isoprene.
5. The process as claimed in claim 2, wherein the methacrylates and
acrylates copolymerized are at least one member selected from the
group consisting of methyl methacrylate, ethyl methacrylate, propyl
methacrylate, n-butyl methacrylate, methyl acrylate, ethyl
acrylate, propyl acrylate, n-butyl acrylate, tert-butyl acrylate,
tert-butyl methacrylate and 2-ethylhexyl acrylate.
6. The process as claimed of claim 2, wherein 1,3-butadiene and
methyl methacrylate are copolymerized.
7. The process as claimed in claim 2, wherein the polyvinyl alcohol
used comprises at least one member selected from the group
consisting of the partially hydrolyzed polyvinyl acetates and
partially hydrolyzed polyvinyl esters which have been rendered
hydrophobic.
8. The process as claimed in claim 2, wherein the polyvinyl alcohol
used comprises partially hydrolyzed polyvinyl acetates having a
degree of hydrolysis of from 80 to 95 mol % and a Hoppler viscosity
of from 1 to 30 mPas.
9. The process as claimed in claim 2, wherein the polyvinyl alcohol
used comprises partially hydrolyzed polyvinyl esters which have
been rendered hydrophobic and, in the form of a 2% strength aqueous
solution, produce a surface tension of .ltoreq.40 mN/m.
10. The process as claimed in claim 9, wherein partially hydrolyzed
polyvinyl acetates having from 84 to 92 mol % of vinyl alcohol
units and from 0.1 to 10% by weight of units which are derived from
vinyl esters of an alpha-branched carboxylic acid having 5 or 9 to
11 carbon atoms in the acid radical, isopropenyl acetate and ethene
are used.
11. The process as claimed in claim 2, wherein a combination of
polyvinyl ester which has been rendered hydrophobic and partially
hydrolyzed polyvinyl acetate is used as the polyvinyl alcohol.
12. The process as claimed in claim 2, wherein the polymerization
is carried out in the presence of regulators.
13. The process as claimed in claim 12, wherein the regulator used
comprises at least one substance selected from the group consisting
of n-dodecyl mercaptan, tert-dodecyl mercaptan, mercaptopropionic
acid, methyl mercaptopropionate, isopropanol and acetaldehyde.
14. The process as claimed in claim 2, wherein the aqueous
dispersions obtained thereby are dried by means of fluidized-bed
drying, freeze-drying or spray-drying.
15. The process as claimed in claim 2, wherein the total amount of
protective colloid and from 5 to 25% by weight of the total amount
of comonomer are initially introduced and the remaining amount of
comonomer is metered in during polymerization.
16. The process as claimed in claim 2, wherein the total amount of
protective colloid and the total amount of comonomer are initially
introduced before the initiation of polymerization and are
polymerized in the presence of a regulator.
17. The process as claimed in claim 2, wherein some of the amount
of comonomer and some of the amount of regulator are initially
introduced, with initial introduction of all of the protective
colloid or with initial introduction of some of the protective
colloid, and the remainder in each case is metered in.
18. An aqueous polymer dispersion or a polymer powder redispersible
in water, obtainable by one of the processes as claimed in claim
2.
19. A chemical product for the building industry, comprised of the
stabilized emulsifier and solvent-free copolymer of claim 1 in
combination with hydraulically setting binders selected from the
group consisting of Portland cement, high-alumina cement, trass
cement, slag cement, magnesia cement and phosphate cement.
20. A chemical product comprised of the stabilized emulsifier and
solvent-free copolymer of claim 1 in combination with at least one
member selected from the group consisting of gypsum, waterglass,
adhesives, renders, coatings, binders, filling compounds, sealing
slurries, joint mortars and paints.
21. The product of claim 20 which is a coating for textiles and
paper.
22. The product of claim 20 which is a packaging or bookbinding
adhesive.
23. The product of claim 20 which is a binder for binding nonwovens
comprising natural synthetic fibers, for the production of moldings
from fiber materials, for the production of precursors of such
moldings, for cotton binding and for the production of
laminates.
24. The product of claim 20 which is an adhesive formulation for
adhesively bonding wood to give a wood-wood bond and adhesively
bonding wood with absorptive substrates, parquet bonding, and
bonding indoor and outdoor tiles.
25. A chemical product for the building industry comprised of the
stabilized and solvent-free copolymer of claim 1 and material based
on CaSO.sub.4.
26. A chemical product for the building industry comprised of the
stabilized and solvent-free copolymer of claim 1 and materials
based on CaCO.sub.3.
Description
BACKGROUND OF THE INVENTION
[0001] 1) Field of the Invention
[0002] The invention relates to polyvinyl alcohol-stabilized
copolymers of 1,3-dienes with methacrylates and/or acrylates in the
form of their aqueous polymer dispersions or polymer powders
redispersible in water, and to a process for their preparation and
their use.
[0003] 2) Background Art
[0004] As explained in WO-A 97/15603, polymer dispersions which are
stabilized with polyvinyl alcohol (PVA1) have characteristic
rheology and tack properties, so that, in contrast to
emulsifier-stabilizer dispersions, they are particularly suitable
for coating and adhesive applications. For example, paper packaging
adhesives prepared using emulsifier-stabilized copolymer
dispersions have poor machine running properties compared with
PVA1-stabilized copolymer dispersions, owing to the fine particles
(particle size in general <400 nm), the rheology and the low
surface tension of the emulsifier-stabilized dispersion. A
disadvantage of the adhesives prepared using vinyl ester-based or
acrylate-based copolymer dispersions is that, owing to their
generally relatively high glass transition temperature (Tg) or the
minimum film formation temperature (MFT), the addition of
plasticizer for processing is necessary.
[0005] Using vinyl acetate/ethylene copolymer dispersions, it is
possible to prepare plasticizer-free paper packaging adhesives
which have improving adhesion properties with increasing ethylene
content and hence associated declining Tg. A disadvantage of the
adhesives prepared using polyvinyl alcohol-stabilized vinyl
acetate/ethylene copolymer dispersions is that the reduction in Tg
due to copolymerization with ethylene is subject to limits owing to
the crystallization of the vinyl acetate/ethylene copolymers.
[0006] By copolymerizing 2-ethylhexyl acrylate, glass transition
temperatures Tg down to below -50.degree. C. can be achieved with
polymer dispersions based on acrylate polymers. However, pure
acrylate dispersions on an alkaline substrate release the
corresponding alcohol at pH>9, owing to hydrolysis of the ester
group. Thus, 2-ethylhexyl alcohol is released from 2-ethylhexyl
acrylate and may be released into the surrounding air. Moreover, by
oxidation of 2-ethylhexyl alcohol to the corresponding acid,
secondary products which are not toxicologically safe can be
produced. A further side effect is that polyacrylic acid domains
having a very high Tg are obtained by hydrolysis of the ester
group. The high Tg in turn has an adverse effect on the
viscoelastic modulus of the resin and hence a negative effect on a
number of performance characteristics such as wetting and
adhesion.
[0007] It was therefore the object to provide a hydrolysis-stable
dispersion or powder type whose polymer resin can be prepared in a
wide Tg range (-80.degree. C.<Tg<+100.degree. C.). The
aqueous dispersion or redispersion should have the advantageous
rheological properties (machine running properties) of polyvinyl
alcohol-stabilized vinyl ester or acrylate dispersions and should
have good adhesion to a very wide range of substrates such as
paper, plastics and minerals, even in the case of low Tg and in the
absence of plasticizer.
[0008] This object was achieved by a process by means of which
polyvinyl alcohol-stabilized copolymers of 1,3-dienes with
methacrylates and/or acrylates are obtainable in the form of their
aqueous polymer dispersions or polymer powders redispersible in
water.
[0009] DE-A 2442121 (GB-A 1438449) disclosed that polyvinyl alcohol
is not effective as a sole dispersant in the preparation of
polymers of (meth)acrylates or butadienes and has therefore always
been used as a mixture with emulsifiers. DE-A 2442121 therefore
recommends the use of a polyvinyl alcohol modified with alkali
metal olefin sulfonate for the preparation of polyvinyl
alcohol-stabilized polymers of (meth)acrylate or butadiene
monomers. The disadvantage is that this too is an ionic stabilizer
and the disadvantages occurring in the case of emulsifiers and
described above therefore also occur.
[0010] WO-A 97/15603 describes butadiene/(meth)acrylate copolymers
which are stabilized with polyvinyl alcohol and emulsifiers and are
obtained by grafting the polyvinyl alcohol moiety onto the
copolymer by means of a functionalized silane, especially
mercaptotrialkoxysilane.
[0011] U.S. Pat. No. 5,200,459 recommends copolymerization in the
presence of a stabilizing solvent, in particular from the group
consisting of the alcohols, for the preparation of polyvinyl
alcohol-stabilized, aqueous butadiene copolymer latices.
[0012] WO-A 99/28360 discloses the preparation of polyvinyl
alcohol-stabilized styrene/butadiene copolymer dispersions or
dispersion powders. However, styrene-containing copolymer
dispersions have the disadvantage of having viscoelastic polymer
properties disadvantageous for many applications (for example in
adhesives) (poor deformability). In the copolymer styrene produces
polymer domains having a high Tg; these lead to relatively
disadvantageous viscoelastic resin properties. This results, for
example in the case of adhesives, in poorer wetting properties and
poorer tack.
[0013] DE-A 19548313 (U.S. Pat. No. 5,733,944) and EP-A 744418
(U.S. Pat. No. 5,733,944) disclose processes for the preparation of
aqueous dispersions of butadiene/(meth)acrylate copolymers which
are prepared in the presence of a protective colloid and an
emulsifier.
[0014] The invention relates to emulsifier- and solvent-free
copolymers, stabilized with nonionic polyvinyl alcohol as
protective colloid, of 1,3-dienes with methacrylates and/or
acrylates in the form of their aqueous polymer dispersions or
polymer powders redispersible in water, obtainable by emulsion
polymerization and optionally drying of the polymer dispersions
obtained thereby, from 10 to 100% by weight of the amount of
polyvinyl alcohol being initially introduced before the initiation
of the polymerization and the remaining amount being metered in
during polymerization, and the addition of polyvinyl alcohol and
the comonomers being controlled in such a way that, during the
polymerization, the amount of protective colloid is always from 1
to 70% by weight of the total amount of free comonomers.
[0015] The invention furthermore relates to a process for the
preparation of emulsifier- and solvent-free copolymers, stabilized
with polyvinyl alcohol as a protective colloid, of 1,3-dienes with
methacrylates and/or acrylates in the form of their aqueous polymer
dispersions or polymer powders redispersible in water, by emulsion
polymerization of a mixture containing one or more comonomers from
the group consisting of the 1,3-dienes and one or more comonomers
from the group consisting of the methacrylates and acrylates, in
the presence of from 1 to 15% by weight, based on the total weight
of the monomers, of one or more polyvinyl alcohols and optionally
drying of the polymer dispersions obtained thereby, from 10 to 100%
by weight of the amount of polyvinyl alcohol being initially
introduced before the initiation of the polymerization and the
remaining amount being metered in during polymerization, and the
addition of polyvinyl alcohol and of the comonomers being
controlled in such a way that, during the polymerization, the
amount of protective colloid is always from 1 to 70% by weight of
the total amount of free comonomers.
[0016] Suitable 1,3-dienes are 1,3-butadiene and isoprene,
1,3-butadiene being preferred. Suitable methacrylates and acrylates
are those of straight-chain and branched alcohols having 1 to 10
carbon atoms. Preferred methacrylates are methyl methacrylate,
ethyl methacrylate, propyl methacrylate and n-butyl methacrylate.
Methyl methacrylate is particularly preferred. Preferred acrylates
are methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl
acrylate, tert-butyl acrylate t-butylmeth acrylate and 2-ethylhexyl
acrylate. Methyl acrylate, n-butyl acrylate and 2-ethylhexyl
acrylate are particularly preferred.
[0017] If required, from 1 to 30% by weight, based on the total
weight of the monomer mixture, of further monomers copolymerizable
with 1,3-dienes and with the (meth)acrylates such as ethylene,
vinyl chloride or vinyl esters of straight-chain or branched
carboxylic acids having 1 to 15 carbon atoms, for example vinyl
acetate, and vinyl esters of alpha-branched monocarboxylic acids
having 5 to 11 carbon atoms such as VeoVa9.RTM. or VeoVa10.RTM.
(trade names of Shell), can also be copolymerized.
[0018] If required, from 0.05 to 10% by weight, based on the total
weight of the monomer mixture, of auxiliary monomers may also be
copolymerized. Examples of auxiliary monomers are ethylenically
unsaturated mono- and dicarboxylic acids, preferably acrylic acid,
methacrylic acid, fumaric acid and maleic acid; ethylenically
unsaturated carboxamides and carbonitriles, preferably acrylamide
and acrylonitrile; mono- and diesters of fumaric acid and maleic
acid such as the diethyl and diisopropyl esters, and maleic
anhydride, ethylenically unsaturated sulfonic acid and its salts,
preferably vinylsulfonic acid or
2-acrylamido-2-methylpropanesulfonic acid. Further examples are
precrosslinking comonomers such as polyethylenically unsaturated
comonomers, for example divinyl adipate, diallyl maleate, allyl
methacrylate or triallyl cyanurate, or postcrosslinking comonomers,
for example acrylamidoglycolic acid (AGA), methylacrylamidoglycolic
acid methyl ester (MAGME), N-methylolacrylamide (NMA),
N-methylolmethacrylamid- e, N-methylol allylcarbamate, alkyl ethers
such as isobutoxy ether, or esters of N-methylolacrylamide, of
N-methylolmethacrylamide and of N-methylol allyl carbamate.
Comonomers having epoxide functional groups such as glycidyl
methacrylate and glycidyl acrylate, are also suitable. Further
examples are comonomers having silicon functional groups such as
acryloyloxypropyltri(alkoxy)silanes and
methacryloyloxypropyltri(alkoxy)s- ilanes, vinyl trialkoxysilanes
and vinylmethyldialkoxysilanes, it being possible, for example, for
ethoxy and ethoxypropylene glycol ether radicals to be present as
alkoxy groups. Monomers having hydroxyl or CO groups may also be
mentioned, for example hydroxyalkyl methacrylates and acrylates
such as hydroxyethyl, hydroxypropyl or hydroxybutyl acrylate or
methacrylate, and compounds such as diacetoneacrylamide and
acetylacetoxy methyl acrylate or methacrylate.
[0019] The choice of monomers or the choice of the amounts by
weight of the comonomers is made in such a way that in general a
glass transition temperature Tg of from -80.degree. C. to
+100.degree. C., preferably from -50.degree. C. to +50.degree. C.,
particularly preferably from -20.degree. C. to +40.degree. C.,
results. The glass transition temperature Tg of the polymers can be
determined in a known manner by means of differential scanning
calorimetry (DSC). The Tg can also be calculated approximately
beforehand by means of the Fox equation. According to Fox T. G.,
Bull. Am. Physics Soc. 1, 3, page 123 (1956), the following is
applicable: 1/Tg=x.sub.1/Tg.sub.1+x.sub.2/Tg.sub.2+ . . .
+x.sub.n/Tg.sub.n, where x.sub.n represents the mass fraction (% by
weight/100) of the monomer n and Tg.sub.n is the glass transition
temperature in degrees Kelvin of the homopolymer of the monomer n.
Tg values for homopolymers are listed in Polymer Handbook, 2nd
Edition, J. Wiley & Sons, New York (1975).
[0020] Mixtures comprising from 20 to 80% by weight, preferably
from 30 to 55% by weight, of (meth)acrylates, in particular methyl
methacrylate, and from 20 to 80% by weight, preferably from 45 to
70% by weight, of 1,3-diene, in particular 1,3-butadiene, are
particularly preferred, it being possible for mixtures optionally
also to contain one or more of the above-mentioned auxiliary
monomers in the stated amounts, and the amounts in % by weight sum
to 100% by weight.
[0021] The preparation of the polyvinyl alcohol-stabilized
copolymers is carried out by the emulsion polymerization process in
the absence of emulsifier, the polymerization temperature being in
general from 40.degree. C. to 100.degree. C., preferably from
60.degree. C. to 90.degree. C. The polymerization with
1,3-butadiene is effected under the vapor pressure of the reaction
mixture, in general between 2 and 15 bar, at the chosen
polymerization temperature. In the copolymerization of gaseous
comonomers, such as ethylene or vinyl chloride, it is also possible
to employ a higher pressure, in general between 5 bar and 100
bar.
[0022] The polymerization is initiated with the at least partially
water-soluble, thermal initiators or redox initiator combinations
customarily used for the emulsion polymerization. Suitable organic
initiators are hydroperoxides such as tert-butyl hydroperoxide,
tert-butyl peroxopivalate, cumyl hydroperoxide or isopropylbenzene
monohydroperoxide, or azo compounds such as azobisisobutyronitrile.
Suitable inorganic initiators are the sodium, potassium and
ammonium salts of peroxodisulfuric acid. Said initiators are used
in general in an amount of from 0.05 to 3% by weight, based on the
total weight of the monomers.
[0023] Combinations of said initiators with reducing agents are
used as redox initiators. Suitable reducing agents are the sulfites
and bisulfites of the alkali metals and of ammonium, for example
sodium sulfite, the derivatives of sulfoxylic acid, such as zinc or
alkali metal formaldehyde sulfoxylates, for example, sodium
hydroxymethanesulfinate, and ascorbic acid. The amount of reducing
agent is preferably from 0.01 to 5.0% by weight, based on the total
weight of the monomers.
[0024] Suitable polyvinyl alcohols are nonionic, partially
hydrolyzed polyvinyl acetates and nonionic, partially hydrolyzed
polyvinyl esters which have been rendered hydrophobic, and mixtures
thereof, it also being possible to use said polyvinyl alcohols as a
mixture with further protective colloids.
[0025] Nonionic, partially hydrolyzed polyvinyl acetates having a
degree of hydrolysis of from 80 to 95 mol % and a Hoppler viscosity
(4% strength aqueous solution, DIN 53015, Hoppler method at
20.degree. C.) of from 1 to 30 mPas, preferably from 2 to 15 mPas
are particularly preferred.
[0026] Nonionic, partially hydrolyzed polyvinyl esters which have
been rendered hydrophobic and, in the form of a 2% strength aqueous
solution, produce a surface tension of .ltoreq.40 mN/m are also
preferred. Suitable partially hydrolyzed polyvinyl esters which
have been rendered hydrophobic can be obtained, for example, by
rendering polyvinyl acetate hydrophobic by copolymerization of
vinyl acetate with hydrophobic comonomers. Examples of these are
isopropenyl acetate, branched and straight-chain vinyl esters
having a long chain, preferably having 7 to 15 carbon atoms such as
vinyl pivalate, or vinyl ethylhexanoate, vinyl esters of saturated
alpha-branched monocarboxylic acids having 5 or 9 to 11 carbon
atoms, dialkyl maleates and dialkyl fumarates of C.sub.1- to
C.sub.12-alcohols such as diisopropyl maleate and diisopropyl
fumarate, vinyl chloride, vinyl alkyl ethers of alcohols having at
least 4 carbon atoms, such as vinyl butyl ether, and C.sub.2- to
C.sub.10-olefins such as ethene and decene. The imparting of
hydrophobic properties can also be effected by polymerization of
vinyl acetate in the presence of regulators such as alkyl
mercaptans having a C.sub.2- to C.sub.18-alkyl radicals such as
dodecyl mercaptan or tert-dodecyl mercaptan. A further possibility
for imparting hydrophobic properties to polyvinyl acetate is by
polymer-analogous reactions, for example acetylation of vinyl
alcohol units in partially hydrolyzed polyvinyl acetate with
C.sub.1- to C.sub.4-aldehydes such as butyraldehyde.
[0027] The proportion of hydrophobic units is preferably from 0.1
to 10% by weight, based on the total weight of the partially
hydrolyzed polyvinyl acetate. The degree of hydrolysis is from 70
to 99.9 mol %, preferably from 84 to 92 mol %, and the Hoppler
viscosity (DIN 53015, Hoppler method, 4% strength aqueous solution)
is from 1 to 30 mPas, preferably from 2 to 15 mPas. Said protective
colloids are obtainable by means of processes known to those
skilled in the art.
[0028] The partially hydrolyzed polyvinyl acetates having from 84
to 92 mol % of vinyl alcohol units and from 0.1 to 10% by weight of
units which are derived from vinyl esters of an alpha-branched
carboxylic acid having 5 or 9 to 11 carbon atoms in the acid
radical, isopropenyl acetate and ethene are particularly preferred
as partially hydrolyzed polyvinyl esters which have been rendered
hydrophobic; in particular the partially hydrolyzed polyvinyl
acetates having vinyl alcohol units and units of vinyl esters of
alpha-branched carboxylic acids having 5 or 9 to 11 carbon atoms in
said amounts. Examples of such vinyl esters are those which are
available as vinyl versatates from Shell, under the names
VeoVa.sup.R5, VeoVa.sup.R9, VeoVa.sup.R10 and VeoVa.sup.R11.
Combinations of the polyvinyl esters which have been mentioned as
being particularly preferred and have been rendered hydrophobic
with partially hydrolyzed polyvinyl acetates having a degree of
hydrolysis of from 80 to 95 mol % and a Hoppler viscosity of from 1
to 30 mPas, preferably from 2 to 15 mPas, which, in the form of a
2% strength aqueous solution, produce a surface tension of >40
mN/m, are also particularly preferred.
[0029] Further suitable protective colloids which can be used as a
mixture with said polyvinyl alcohols are polyvinylpyrrolidones,
carboxymethylcellulose, methyl-cellulose, hydroxyethylcellulose and
hydroxypropyl-cellulose, starches, dextrins, cyclodextrins,
poly(meth)acrylic acid, poly(meth)acrylamides, polyvinylsulfonic
acids, melamine formaldehyde sulfonates, naphthalene formaldehyde
sulfonates, and styrene/maleic acid and vinyl ether/maleic acid
copolymers.
[0030] The protective colloids are added during the polymerization
in general in a total amount of from 1 to 15% by weight, based on
the total weight of the monomers. Where a protective colloid
combination is used, the weight ratio of hydrophobic, partially
hydrolyzed polyvinyl ester to nonhydrophobic, partially hydrolyzed
polyvinyl alcohol, is from 10/1 to 1/10.
[0031] For controlling the molecular weight, regulating substances
(regulators) are preferably used in the polymerization. Examples of
such substances are n-dodecyl mercaptan, tert-dodecyl mercaptan,
mercaptopropionic acid, methyl mercaptopropionate, isopropanol and
acetaldehyde. They are usually used in amounts of from 0.01 to 5.0%
by weight, preferably from 0.5 to 2.0% by weight, based in each
case on the monomers to be polymerized.
[0032] For initiating the polymerization, all of the initiator is
initially introduced, some of it is initially introduced and some
metered, or all of the initiator is metered in. The total amount of
the polyvinyl alcohol or the total amount of further protective
colloid and the total amount of the comonomers can be initially
introduced. Some can be initially introduced and some metered, or
the total amounts can be metered. In a preferred embodiment, the
total amount of protective colloid and from 5 to 25% by weight of
the total amount of comonomer are initially introduced and the
remaining amount of comonomer is metered in during the
polymerization. In a further preferred embodiment, the total amount
of protective colloid and the total amount of comonomer are
initially introduced before initiation of the polymerization and
polymerized in the presence of regulator. A procedure in which all
of the protective colloid is initially introduced or some of the
protective colloid is initially introduced and some of the amount
of comonomer and some of the amount of regulator are initially
introduced and the remainder in each case is metered in is also
preferred. In a possible procedure here, comonomers and regulator
are initially introduced and are metered in a constant ratio. The
ratio of regulator to comonomer in the initially introduced mixture
is greater than that during metering; for this purpose, preferably
15 to 50% by weight of the total amount of the regulator are
initially introduced and from 5 to 25% by weight of the total
amount of the comonomers are initially introduced.
[0033] When a protective colloid combination is used, one component
of the protective colloid combination, preferably the hydrophobic,
partially hydrolyzed polyvinyl ester, can be initially taken and
the other component metered, or a part of the mixture initially
taken and the remainder metered in as an aqueous solution.
[0034] After the end of the polymerization, postpolymerization can
be effected using known methods for removing residual monomers, for
example by postpolymerization initiated with a redox catalyst.
Volatile residual monomers can also be removed by means of
distillation, preferably under reduced pressure, and optionally
while passing through or passing over inert entraining gases such
as air, nitrogen or steam.
[0035] The aqueous dispersions obtainable with the process
according to the invention have a solids content of from 30 to 75%
by weight, preferably from 40 to 65% by weight. For the preparation
of polymer powders redispersible in water, the aqueous dispersions
are dried, for example by means of fluidized-bed drying,
freeze-drying or spray-drying. Preferably, the dispersions are
spray-dried. The spray-drying is effected in conventional spray
drying units, it being possible to carry out the atomization by
means of airless high-pressure nozzles, binary nozzles or
multi-media nozzles or using a rotating disk. The outlet
temperature is generally chosen in the range from 55.degree. C. to
100.degree. C., preferably from 70.degree. C. to 90.degree. C.,
depending on the unit, the Tg of the resin and the desired degree
of drying.
[0036] The total amount of protective colloid before the drying
process should preferably be at least 10% by weight, based on the
amount of polymer. To ensure redispersibility, it is as a rule
necessary to add further protective colloids as an atomization aid
to the dispersion prior to drying. As a rule, the atomization aid
is used in an amount of from 5 to 25% by weight, based on the
polymeric components of the dispersion.
[0037] Suitable atomizing aids are partially hydrolyzed polyvinyl
acetates; polyvinylpyrrolidones; polysaccharides in water-soluble
form such as starches (amylose and amidopectin), celluloses and
their carboxymethyl, methyl, hydroxyethyl and hydroxypropyl
derivatives; proteins such as casein or caseinate, soy protein,
gelatin; ligninsulfonates; synthetic polymers such as
poly(meth)acrylic acid, copolymers of (meth)acrylates with
comonomer units having carboxyl functional groups,
poly(meth)acrylamide, polyvinyl-sulfonic acids and their
water-soluble copolymers; melamine formaldehyde sulfonates,
naphthalene formaldehyde sulfonates and styrene/maleic acid and
vinyl ether/maleic acid copolymers. Preferred atomization aids are
partially hydrolyzed polyvinyl acetate having a degree of
hydrolysis of from 80 to 95 mol %, a Hoppler viscosity of from 1 to
30 mPas, which may have been modified with isopropenyl acetate or
vinyl ether units.
[0038] During the atomization, a content of up to 1.5% by weight of
antifoam, based on the base polymer, has in many cases proven
advantageous. For increasing the shelf-life by improving the
blocking stability, in particular in the case of powders having a
low glass transition temperature, an antiblocking agent (anticaking
agent) can be added to the powder obtained, preferably in an amount
of up to 30% by weight based on the total weight of polymeric
components. Examples of antiblocking agents are calcium and
magnesium carbonate, talc, gypsum, silica and silicates having
particle sizes preferably in the range from 10 nm to 10 .mu.m.
[0039] For improving the performance characteristics, further
additives may be added during the atomization. Further components
of dispersion powder compositions, which are present in preferred
embodiments are, for example, pigments, fillers, foam stabilizers
and water repellents.
[0040] The polyvinyl alcohol-stabilized 1,3-diene/(meth)acrylic
acid copolymers can be used in the form of their aqueous polymer
dispersions or polymer powders redispersible in water, in the
applications typical for them, for example, in chemical products
for the building industry in combination with hydraulically setting
binders such as cements (Portland cement, high-alumina cement,
trass cement, slag cement, magnesia cement and phosphate cement),
gypsum or waterglass, for the preparation of construction
adhesives, renders, filling compounds, floor filling compounds,
sealing slurries, joint mortars and paints, and furthermore, as
sole binders for coating materials and adhesives or as coating
materials or binders for textiles and paper.
[0041] An example of the use as an adhesive is the adhesive bonding
of porous substrates such as the adhesive bonding of wood to give a
wood-wood bond, the adhesive bonding of wood to absorptive
substrates such as floor topping, in particular parquet bonding.
Further applications are the water-resistant adhesive bonding of
paper and board, for example, as packaging adhesive and bookbinding
adhesive. As adhesives, the copolymers are also suitable for the
adhesive bonding of fiber materials comprising natural or synthetic
fibers, for example, for the production of wood fiberboards, for
binding nonwovens comprising natural or synthetic fibers, with the
production of moldings from fiber materials and for the production
of precursors of such moldings, the so-called semifinished products
(waddings). Further application examples are the binding of cotton,
for example, of upholstery, insulation and filter waddings, and the
production of laminates such as insulating materials.
[0042] Preference is given to the use as gypsum mortar for filling
compounds, joint fillers, flowable CaSO.sub.4 floor toppings, joint
compounds or adhesive mortars or the use for the production of
plasterboards or plaster shapes. Further applications are, for
example, renders or stucco work, including outdoors. The customary
applications for the corresponding and modified CaCO.sub.3
materials are as joint fillers, gypsum-free filling compounds and
renders. In general, the copolymer is used in an amount of from 0.2
to 15% by weight, based on the dry weight of the formulation.
[0043] The use in self-leveling floor filling compounds (leveling
compounds) and floor toppings is also preferred. Preferably, from
0.5 to 10% by weight of dispersion powder, based on the dry weight
of the formulation, are added. The formulations also contain from 5
to 80% by weight of inorganic, hydraulically setting binders, such
as cement, gypsum or mixtures thereof. The formulation also
contains from 5 to 80% by weight of inorganic fillers such as sand,
quartz powder, chalk, limestone powder, filter ash or mixtures
thereof. In order to improve the leveling properties, additives
which promote leveling such as casein or cement liquefiers can, if
required also be added to the dry mixture. The data in % by weight
are always based on 100% by weight of dry mass in the formulation
for floor filling compounds. The ready-to-use leveling compound is
finally obtained by mixing water with the above-mentioned dry
mixture.
[0044] The ready-to-use floor filling compound mixed with water can
be used for the production of floor toppings and self-leveling
coatings for leveling, evening out and smoothing surfaces.
[0045] A further preferred use of the dispersions and powders is
that in cement-containing construction adhesive formulations.
Typical formulations contain from 5 to 80% by weight of cement,
from 5 to 80% by weight of fillers such as quartz sand, calcium
carbonate or talc, from 0.1 to 2% by weight of thickeners such as
cellulose ethers, sheet silicates or polyacrylates, from 0.5 to 60%
by weight of the PVA1-stabilized (meth)acrylate/1,3-diene
copolymers in the form of the polymer dispersion or the polymer
powder and optionally, further additives for improving stability,
processibility, open time and water resistance. The data in % by
weight are always based on 100% by weight of dry mass of the
formulation. Said cement-containing construction adhesive
formulations are used in particular as tile adhesives for laying
tiles of all kinds (earthenware, stoneware, porcelain, ceramic,
natural tiles) indoors and outdoors and are mixed with the
corresponding amount of water before their use.
[0046] An advantage of the (meth)acrylate/1,3-diene copolymers
prepared according to the invention is their hydrolysis stability
which improves with increasing 1,3-diene content compared with pure
acrylate copolymers. Consequently, the mechanical copolymer
properties such as tensile strength and elongation at break, remain
unchanged even on application to alkaline surfaces. Furthermore, no
toxicological controversial alcohols such as, for example, butanol
or 2-ethylhexanol, or only small amounts thereof, are released on
alkaline surfaces with such hydrolysis-stable systems. Compared
with styrene/acrylate copolymers, the copolymers prepared according
to the invention have, owing to their advantageous viscoelastic
properties, in particular for adhesive applications, improved
performance characteristics, in particular, high surface tack, high
adhesion (peel strength) and high cohesion (shear stability). The
outstanding cement stability, in particular of the copolymers
stabilized with hydrophobically modified polyvinyl alcohols, is
also noteworthy. The (meth)acrylate/1,3-diene copolymers prepared
according to the invention also have the advantageous Theological
properties (machine running properties) of vinyl ester or acrylate
dispersions stabilized with polyvinyl alcohol.
[0047] The following examples serve for further explanation of the
invention:
EXAMPLE 1
[0048] 1110 ml of demineralized water, 538 g of a 20% strength by
weight aqueous solution of a partially hydrolyzed polyvinyl acetate
having a degree of hydrolysis of 88 mol %, a Hoppler viscosity of
the 4% strength solution of 4 mPas (DIN 53015, Hoppler method at
20.degree. C.), which, when dissolved in water in an amount of 2%
by weight, produced a surface tension of 44 mN/m, and 363 g of a
20% strength by weight aqueous solution of a partially hydrolyzed
copolymer of vinyl acetate and VeVoa.sup.R10, having a degree of
hydrolysis of 88 mol %, a Hoppler viscosity of the 4% strength
solution of 4 mPas, which, when dissolved in water in an amount of
2% by weight, produced a surface tension of 37 mN/m, were initially
introduced into a stirred autoclave having a capacity of about 5 1.
The pH was adjusted to 4.0 to 4.2 with 10% strength by weight
formic acid. Thereafter, evacuation was effected, flushing was
carried out with nitrogen, evacuation was effected again and a
mixture of 151 g of methyl methacrylate, 129 g of 1,3-butadiene and
8.5 g of tert-dodecyl mercaptan was sucked in. This mixture was
stabilized to prevent premature polymerization by adding 30 mg of
benzoquinone.
[0049] After heating up to 80.degree. C., the polymerization was
initiated by simultaneously introducing two catalyst solutions, the
first of which comprised 110 g of demineralized water and 15.5 g of
a 40% strength aqueous tert-butyl hydroperoxide solution and the
other comprised 116 g of demineralized water and 13 g of sodium
formaldehyde sulfoxylate, the metering of the two catalyst
solutions being effected at the same feed rate (18 ml/h). After the
beginning of polymerization, the metered addition of a mixture of
729 g of 1,3-butadiene, 856 g of methyl methacrylate and 9.5 g of
tert-dodecyl mercaptan was started at a rate of 5.3 g/min. After
the end of the monomer feed, postpolymerization was effected for a
further 2 h at 80.degree. C. with unchanged feed rate of the
initiator solution, after which the feed of the initiator solutions
was ended and cooling was carried out.
[0050] A stable, coarse-particled (Coulter LS 230; Dw=950 nm) and
coagulum-free dispersion which had a solids content of 51% and a
viscosity (Brookfield viscometer, 20.degree. C., 20 rpm) of 380
mPas was obtained.
EXAMPLE 2
[0051] The dispersion was prepared analogously to Example 1 but
with initial introduction of 900 g of a 20% strength by weight
aqueous solution of a partially hydrolyzed polyvinyl acetate having
a degree of hydrolysis of 88 mol %, a Hoppler viscosity of the 4%
strength solution of 4 mPas, which, when dissolved in water in an
amount of 2% by weight, produced a surface tension of 44 mN/m, as
the only protective colloid. All other measures corresponded to
Example 1.50% by weight of a 10.3% strength by weight solution of
polyvinyl alcohol (partially hydrolyzed polyvinyl acetate, degree
of hydrolysis 88 mol %) were added to the dispersion and the latter
was sprayed through a binary nozzle. The atomization component used
was air precompressed to 4 bar, and the drops formed were dried by
the countercurrent method with air heated to 125.degree. C. 10% of
commercial antiblocking agent (mixture of calcium magnesium
carbonate and magnesium hydrosilicate) were added to the dry powder
obtained.
[0052] A 50% strength redispersion of the powder was used for
testing.
EXAMPLE 3
[0053] The dispersion was prepared analogously to Example 1 but
with initial introduction of 900 g of a 20% strength by weight
aqueous solution of a partially hydrolyzed copolymer of vinyl
acetate and VeoVa.sup.R10 having a degree of hydrolysis of 88 mol %
and a Hoppler viscosity of the 4% strength solution of 4 mPas,
which, when dissolved in water in an amount of 2% by weight,
produced a surface tension of 37 mN/m, as the only protective
colloid. All other measures corresponded to Example 1.
[0054] The dispersion was dried analogously to Example 2. A 50%
strength redispersion of the powder was used for testing.
EXAMPLE 4
[0055] The dispersion was prepared analogously to Example 1, 800 g
of a 10% strength by weight aqueous solution of a yellow dextrin
(Avedex 35, from Avebe), which, when dissolved in water in an
amount of 2% by weight, produced a surface tension of 50 mN/m,
together with the hydrophobically modified polyvinyl alcohol, being
used instead of the partially hydrolyzed polyvinyl acetate. All
other measures corresponded to Example 1.
EXAMPLE 5
[0056] The dispersion was prepared analogously to Example 1 but
with initial introduction of 137 g of methyl methacrylate, 143 g of
1,3-butadiene and 9.4 g of tert-dodecyl mercaptan. A mixture
consisting of 777 g of methyl methacrylate, 808 g of 1,3-butadiene
and 10.5 g of tert-dodecyl mercaptan was metered in. All other
measures corresponded to Example 1.
EXAMPLE 6
[0057] The dispersion was prepared analogously to Example 1 but
with initial introduction of 120 g of methyl methacrylate, 159 g of
1,3-butadiene and 10.4 g of tert-dodecyl mercaptan. A mixture
consisting of 682 g of methyl methacrylate, 904 g of 1,3-butadiene
and 11.6 g of tert-dodecyl mercaptan was metered in. All other
measures corresponded to Example 1.
EXAMPLE 7
[0058] The dispersion was prepared analogously to Example 1 but
with initial introduction of 103 g of methyl methacrylate, 176 g of
butadiene and 11.5 g of tert-dodecyl mercaptan. A mixture
consisting of 587 g of methyl methacrylate, 999 g of 1,3-butadiene
and 12.9 g of tert-dodecyl mercaptan was metered in. All other
measures corresponded to Example 1.
EXAMPLE 8
[0059] The dispersion was prepared analogously to Example 1 but
with initial introduction of 84 g of methyl methacrylate, 196 g of
butadiene and 12.8 g of tert-dodecyl mercaptan. A mixture
consisting of 475 g of methyl methacrylate, 1110 g of 1,3-butadiene
and 14.3 g of tert-dodecyl mercaptan was metered in. All other
measures corresponded to Example 1.
COMPARATIVE EXAMPLE 1
[0060] The dispersion was prepared analogously to Example 1 but
with initial introduction of 78 g of styrene and 201 g of n-butyl
acrylate. A mixture consisting of 444 g of styrene and 1142 g of
n-butyl acrylate was metered in. The addition of tert-dodecyl
mercaptan was dispensed with. All other measures corresponded to
Example 1.
COMPARATIVE EXAMPLE 2
[0061] The dispersion was prepared analogously to Example 1,
styrene being used instead of methyl methacrylate, both in the
initially introduced mixture and in the metering. All other
measures corresponded to Example 1.
COMPARATIVE EXAMPLE 3
[0062] The dispersion was prepared analogously to Example 1 but
with initial introduction of 78 g of methyl methacrylate and 201 g
of n-butyl acrylate. A mixture consisting of 444 g of methyl
methacrylate and 1142 g of n-butyl acrylate was metered in. The
addition of tert-dodecyl mercaptan was dispensed with. All other
measures corresponded to Example 1.
COMPARATIVE EXAMPLE 4
[0063] The dispersion was prepared analogously to Example 1 but
with initial introduction of 137 g of styrene, 143 g of
1,3-butadiene and 9.4 g of tert-dodecyl mercaptan. A mixture of 777
g of styrene, 808 g of 1,3-butadiene and 10.5 g of tert-dodecyl
mercaptan was metered in. All other measures corresponded to
Example 1.
COMPARATIVE EXAMPLE 5
[0064] The dispersion was prepared analogously to Example 1 but
with initial introduction of 120 g of styrene, 159 g of
1,3-butadiene and 10.4 g of tert-dodecyl mercaptan. A mixture of
682 g of styrene, 904 g of 1,3-butadiene and 11.6 g of tert-dodecyl
mercaptan was metered in. All other measures corresponded to
Example 1.
COMPARATIVE EXAMPLE 6
[0065] The dispersion was prepared analogously to Example 1 but
with initial introduction of 103 g of styrene, 176 g of
1,3-butadiene and 11.5 g of tert-dodecyl mercaptan. A mixture of
587 g of styrene, 999 g of 1,3-butadiene and 12.9 g of tert-dodecyl
mercaptan was metered in. All other measures corresponded to
Example 1.
COMPARATIVE EXAMPLE 7
[0066] The dispersion was prepared analogously to Example 1 but
with initial introduction of 84 g of styrene, 196 g of
1,3-butadiene and 12.8 g of tert-dodecyl mercaptan. A mixture of
475 g of styrene, 1110 g of 1,3-butadiene and 14.3 g of
tert-dodecyl mercaptan was metered in. All other measures
corresponded to Example 1.
[0067] Testing the Performance Characteristics:
[0068] For all measurements, the dispersions or redispersions to be
tested were applied to the substrate film by means of a doctor
blade in a thickness such that a uniform polymer layer of from 24
to 26 g/m.sup.3 remained after drying.
[0069] Surface Tack:
[0070] A 20 cm long and 2.5 cm wide polymer strip (substrate
material: PVC containing polymer plasticizer, 0.1 mm thick) was
clamped in the upper jaw of a tensile tester in the form of a loop,
suspended vertically with the polymer layer facing outward. The
"loop" was then placed in a length of about 3 cm on a horizontally
fastened, carefully cleaned glass plate, without application of
pressure, vertically at a speed of 100 mm/minute, by bringing
together the two jaws of the tensile tester. The polymer strip was
then immediately pulled off from the surface at the same speed. The
highest force required for pulling off the loop was taken as a
measure of the surface tack. The stated value in N/2.5 cm is the
mean value of five individual measurements, a fresh polymer strip
and a fresh glass surface being used each time.
[0071] Adhesion (Peel Strength PS):
[0072] A 20 cm long and 2.5 cm wide polymer strip was placed,
without bubbles, starting from one end in a length of about 12 cm,
on a carefully cleaned crystal glass surface. The polymer strip was
pressed down by rolling five times (back and forth) with a 2.2 kg
steel roll covered with silicone rubber. After storage for eight
minutes and 24 hours in a conditioning chamber at 23.degree. C. and
50% relative humidity, the polymer strip was peeled off over a
length of 5 cm at a speed of 300 mm/minute at an angle of
180.degree.. The average force required for this purpose was
measured. The stated values in N/2.5 cm are mean values of five
individual measurements in each case.
[0073] Cohesion (Shear Stability SS):
[0074] A 5 cm long and 2.5 cm wide polymer strip was placed,
without bubbles, with an area of 2.5 cm.times.2.5 cm, on a
carefully cleaned glass plate so that the remaining piece of
polymer strip projected beyond the edge of the glass plate. The
strip was pressed down by rolling (five times back and forth) with
a 2.2 kg steel roll covered with silicone rubber. After a bonding
time of eight minutes, a glass plate was fastened in a holder at an
angle of 2.degree. to the perpendicular (in order reliably to rule
out peel forces) in such a way that the free end of the polymer
strip hung down. A weight of 2 kg was freely suspended from this
end. The time taken for the free end of the polymer strip to become
detached from the glass plate under the tension of the weight was
determined. The measurement was carried out in a conditioning
chamber at 23.degree. C. and 50% relative humidity. The stated
values in minutes are mean values of three individual measurements
in each case.
[0075] Determination of the Hydrolysis Stability:
[0076] A representative sample was taken from the dispersions
having a solids content adjusted to 50% by weight (with
demineralized water) and the dispersion was to contain no air
bubbles. With the aid of a film castor, a dispersion film having a
wet film thickness of 500 .mu.m was produced on a substrate
material (substrate material: PVC containing polymer plasticizer,
0.1 mm thick) and was subsequently dried to room temperature for 24
h with formation of a polymer film. Film pieces measuring 10
cm.times.10 cm were then punched out of the dispersion film
obtained. A 10 cm.times.10 cm film piece was then introduced into a
500 ml conical flask filled with 350 ml of aqueous 1.0 N potassium
hydroxide solution. The conical flask was closed with a stopper and
was left at 70.degree. C. in a conditioning chamber for 24 h.
Thereafter, the dispersion film was removed from the KOH solution,
washed with demineralized water and dabbed dry with a paper web.
The film piece treated with alkali and an untreated film piece were
dried for 24 h under standard temperature and humidity conditions
(23.degree. C., 50% atmospheric humidity) before test specimens
measuring 50 mm.times.8 mm, according to DIN 53504/NSt S3a, were
punched out of them. Test specimens of the dispersion film treated
with alkali and of the untreated dispersion film were then tested
with respect to tensile strength and elongation at break under
standard conditions according to DIN 53504.
[0077] The test results are summarized in table 1.
[0078] Comparison of Example 1 with comparative Examples 1 and 2
shows that the 1,3-butadiene/methyl methacrylate copolymers have
substantially better adhesion and cohesion than the corresponding
styrene/butyl acrylate (comparative Example 1) and
styrene/1,3-butadiene copolymers.
[0079] Comparison of Example 1 with comparative Example 3 shows
that the 1,3-butadiene/methyl methacrylate copolymers are
substantially more stable to hydrolysis than the corresponding
butyl acrylate/methyl methacrylate copolymer. In the case of the
latter, the alkali treatment leads to a substantial deterioration
in elongation at break and tensile strength.
[0080] Comparison of Examples 5 to 8 with comparative Examples 4 to
7 shows that the methyl methacrylate/butadiene copolymers have
substantially better tack than the styrene/butadiene copolymers, Tg
being identical.
1 TABLE 1 Untreated Alkali-treated Tack PS Tg EB TS EB TS [N/ SS
[N/2.5 Ex. Polymer [.degree. C.] [%] [N/mm.sup.2] [%] [N/mm.sup.2]
2.5 cm] [min] cm] 1 Bu/NNA -10 345 12.3 305 10.1 2.1 2100 10.3 2
Bu/MMA -10 332 13.1 301 11.2 2.0 2300 11.1 3 Bu/MMA -10 360 12.7
306 10.8 2.2 2250 10.8 4 Bu/MMA -10 310 13.3 295 11.5 2.1 2400 10.9
5 Bu/MMA -20 395 14.7 370 14.9 5.1 >3000 12.9 6 Bu/MMA -30 450
16.1 455 15.9 8.7 >3000 14.9 7 Bu/MMA -40 485 18.3 478 18.2 11.5
>3000 16.0 8 Bu/MMA -50 520 19.1 526 19.0 14.1 >3000 19.4
Com. 1 Pt/A -10 298 10.5 290 8.7 1.3 320 7.3 Com. 2 St/Bu -10 335
13.2 330 12.5 1.8 420 6.9 Com. 3 MMA/A -10 256 14.3 155 6.2 2.3
1900 10.2 Com. 4 St/Bu -20 365 16.3 355 16.1 2.1 1600 8.3 Com. 5
St/Eu -30 420 18.5 415 18.1 4.1 2150 9.8 Com. 6 St/Eu -40 480 19.2
482 19.0 4.7 2850 10.4 Com. 7 St/Bu -50 523 19.3 510 19.1 5.8
>3000 11.7 Bu = 1,3-butadiene, MMA = methyl methacrylate, St =
styrene, A = n-butyl acrylate
* * * * *