Note: Descriptions are shown in the official language in which they were submitted.
~Z97Z9L9
~LKALINE C[~RING EMULSIONS FOR USE IN cE2~Nr ADMI~RES
BACK(~;ROUND OF THE INVhrNTION
This invention relates to cement admixtures containing an aqueous
emulsion of an alkaline-curable polymer. The resulting cement mortars
have excellent adhesion, flexibility, an~ waterproofin3 properties.
Aqueous emulsions of synthetic polymers have been added to cement
admixtures which are used for the surface finishing of buildings or
structures. The resulting cement mortars have shown improvements in
adhesion, crack-resistance, impact-resistance, abrasion-resistance,
flexibility, and waterproofing properties. The aqueous emulsions used
have included synthetic rubber latex, acrylate emulsion, ethylene-vinyl
acetate emulsion, and ethylene-vinyl chloride emulsion. Of these, the
synthetic rubber latices are excellent in water~ and alkali-resistance,
but unsatisfactory in ozone-resistance, heat resistance, and ~eather-
resistance. Hence, they do not provide satisfactory cements. Ethylene-
vinyl acetate emulsions provide good adhesion but are poor in water-
resistance,alkali-resistance, and weather-resistan~e. Ethylene-vinyl
~,
:
lZ97Z~9
chlorid~ emulsions have gocd adhesion and alkali-resistance, but are poor
in heat-resistance and weather-resistance. Acrylate emulsions have a good
balance of properties and have been widely used to provide the best cement
admixtures.
Although acrylate emulsions have been used widely, attempts have been
made to improve their performance, specifically to improve the adhesion of
the cement mortar. One such attempt has been the introduction of carboxyl
and epoxide groups into an ac~ylate polymer by polymerization with
ethylenically unsaturated monomers containing such groups. Another
attempt has been the introduction of a cationic charge into an acrylate
polymer by polymerization with an ethylenically unsaturated cationic
monomer such as alkylaminoethylmethacrylate. However, in some cases, the
adhesion of the resulting oement mortar to certain adherents is still
unsatisfactory, e.g., to adherents such as glazed ceramic tiles, plastic
floor surfaees (epoxy resin, urethane resin, polyvinyl chloride, and the
like), asphalt,concrete, steel, and plywood, as well as old and weathered
concrete and mortar.
In order to increase the flexibility of the cement ~ortar, acrylate
polymers havi~ a low Tg are added in large amounts~ The use of the low
Tg polymers results in poor adhesion due to low cohesive strength. m ere
is also a limitation on the amount of polymer e~ulsion which can be added
to the cement. Hence, good adhesion and good flexibility have not been
obtained simultaneously using the same polymer emulsion.
SUMMARY OF T9E INUENTION
5 The present invention provides a c~ment admixture which results in a
~2~
cement mortar which h~s excellent adhesion to various adherents a~d ~hich
maintains excellent Elexibility over a wide range of temperatures
including very low temperatures. The cement admixture comprises a cement
and an efEective amount of an ~queous emulsion of an acrylate polymer
having a Tg below 1~ C to -40 C, which comprises a polymer o~ (a) about
25 to 9Y.57, of a hyd~olytically-stable acrylate monomer, (b) about
0.5-15~ by weight of the total polymer weight of an alkaline-curable cationic
quaternary ammonium salt monomer, (c) 0-70~ of a hydrolytically-stable mono~er
other than (a) or (b), and (d) 0-30~ of a hydrolytically-unstable monomer
other than (a) or (b) with the percentages being by weight and totalling 100%;
the acrylate units in the polymer being represented by the formula
--CH C--
COO~ ~
and with the alkaline-curable cationic quaternary ammonium salt units in
the polymer bein3 represented by the formula
CH2 C
O=C R2
l +
A ~CH2)n I CH2 CIH I 2
R3 OH X
where R is hydrogen or a methyl group; R is a Cl-C12 alkyl group or a
C6-C12 cycloalkyl group with the proviso that R is not C1 or C2 when R is
H; R2 and R3 may be the same or different and are a methyl or ethyl gro~p;
A is -O- or -NH-; X i5 chlorine, bromine, or iodine; Y is an organic or
7~
inorganic monovalent anion; and n is 2 or 3. The practitioner will
recognize that the halohydrin gro~p (i.e., -CH-CH2J will be in epoxide
O~i X
orm (i.e., ~ ~H2-) under alkaline conditions.
O
Aqueous emulsions of the above alkaline-curable cationic acrylate
resins are effectively absorbed by the anionically charged cement
particles. me cement and polymer particles are evenly distributed. The
functional group (-CH-CH2) on the particle surface of the polymer are
OH X
crosslinked in the presence of the alkalLne cement. When the cement is
used as a mortar, it contains sand. When the cement is used as a paint,
it may or may not contain a fine sand. The resulting oement mortar shows
high adhesive strength even with difficult bonding surfaces. m e
resulting cement paint shows improved flexibility and adhesion. Thus, it
is possible to improve the low temperature flexibility without reducing
the adhesive strength.
Typical alkyl or cycloalkyl acrylates or methacrylates include methyl
methyacrylate, ethyl methacrylate, propyl acrylate or methacrylate, butyl
acrylate or methacrylate, amyl acrylate or methacrylate, hexyl acrylate or
methacrylate, 2-ethylhexyl acrylate or methacrylate, n-octyl acrylate or
methacrylateJ decyl acrylate or methacrylate, lauryl acrylatR or methacry-
late, and cyclohexyl acrylate or methacrylate. These can be used alone or
in combination. If necessary, other monomers which can be copolymerized
with the above-described monomers can be included. m ese incl~de hydroly-
-
tically-s~able monomers such as styrene and its derivatives, acrylonitrile
or methacrylonitrile, acrylic acid or methacrylic acid, vinyl pyridine,
2~
vinyl pyrrolidinone, alkyl amino acrylate or methacrylate, N,N'-dialkyl
ac~ylamide or methacrylamide, dimethyla~inopropyl acrylamide or
methac~ylamide in amoi~nts up to about 70~0 by weight. ~ydrolytically-
unstable monomers such as methyl acrylate, ethyl acrylate, vinyl acetate,
vi~yl chloride, and vinyl ethers may also ~e used in amounts which do
not affect the hydroly~ic stability of the polymer, e.g., up to 30%
by weight. The term "hydrolytically-stable monomer", as used herein,
means a monomer which does not hydrolyze at a pH a~ove 1~.
The preferred polymers contain about 40-60%, most preferably 50%
methylmethacrylate or styrene, 40-60%, most preferably 50%, butyl
acrylate, 1-10% of the cationic monomer, and optionally 2-ethylhexyl
acrylate, with t~e percentages totaling 100% and ~eing selected to give a
polymer within the preferred Tg range of 0 to -10C.
The alkaline~curable cationic quaternary ammonium monomers useful
herein are the adducts of an epihalohydrin and a dialkylaminoalkyl
acrylamide or me~lacrylamide (where A is -NH-) or acrylate or methacrylate
~where A is -O-). These cationic halohydrin-con~aining monomers are
described in U.S. Pat. No. 3,095,390 issued June 25, 1963 to A. Maeder
'which covers the methacrylamides) and UOS. Pat. No. 3,694,393 issued
September 26, 1972 to S. N. Lewis (which covers the methacrylate).
Iypical adducts include adducts dimethylaminoethyl acrylate or
methacryla~e, diethylaminoethyl acrylate or methacrylate, dimethylamino-
propyl æ rylate or methacrylate, diethylamm oethyl acrylamide or
methacrylamide, diethylaminopropyl acrylamideor methacrylamide~ and the
like. The monomers are used in the salt fonm. Various salts are
sui~able. Typical inorganic anions include chloride, bramide, sulfa~e and
,, ~ .. ... . . . ....... .. ..
~%~2~
nitrate. Typical organic anions include acetate, benzosulfonate and
lauryl sulfonate. ~he preferred monomers are the chlorides or nitrates
of dimethylaminoethyl methacrylate, dimethylarninopropyl methacrylate, and
dimethylarninopropyl methacrylarnide. m ey are easy to manufacture or
purchase and give acrylate polyners having good perfo~nance.
The amount of quaternary ammonium salt monomer ~sed i5
preferably 0.5-15~, preferably 1-10%, by weight of the total pol~ner.
Below 0.5~ the improvenent in adhesion and flexibility is insufficient and
above 15%, the crosslinking density is too great, causing the polymer, and
consequently the cement mortar, to become brittle.
The aqueous emulsions herein can be prepared by known polymerization
methods, that is, by charging the above monomers with an initiator into a
reactor with an agitator and a jacket or controlling the tem~erature and
p~lymerizin~ at 50-80C and atmospheric pressure for 3-8 hrs. Conventional
initiators and other polymerization additives such as surfactants and/or
protective colloids may be used.
As the initiator, a peroxide or a combination of a peroxide and
reducing agent typically is used. The preferred peroxides include:
potassium sulfate, ammonium persulfate, sodium persulfate, or hydrogen
peroxide. me preferred reducing agents include sodium bisulfite, sodium
hydrosulfite and ferrous salts (e.g.r ferrous sulfate/tartaric acid). The
thiosulfate initiators are ~mployed in known catalytic amounts, preferably
about 0.02-5% by weight based on the weight of the total monomers.
As surfactants, all conventional types can be used, hGwever, it is
preferable to use a nonionic or cationic surfactant in order to provide
the desired performanoe of the acrylate polymer. The preferred nonionic
surfactants include polyoxyethylene alkyl ether, polyoxyethylene
~LZ~7Z~
alkyl~henol ether, and oxyethylene oxypropylene block copolymers. The
preferred cationic surfactants include lauryl trimethyl ammonium chloride
and alkylbenzyl dimethyl ammonium chloride. Although anionic surfactants
are not as effective as the nonionic or cationic surfactants, they can be
used. Suitable anionic surfactants are an alkali salt of a higher alcohol
sulfate, alkali salt of alkylbenzene sulfonate, alkali salt of
aIkylnaphthalene sulfonate, alkali salt of polyoxyethylene alkyl sulfate,
or alkali salt of polyoxyethylene alkylphenyl sulfate.
As protective colloids, most of the known water soluble polymers can
be used. m ese incl~de fully or partially hydrolyzed polyvinyl alcohol,
an alkali salt of a fully or partially hydroly2ed sulfonated polyvinyl
alcohol, cellulose derivatives such as methyl oe llulose and hydroxyethyl
cellulose, polyethylene glycol, and polypropylene glycol. The amount of
protective colloid i~ preferably 0.2~10~, ~ore preferably 2-5%, by weight
based on the total weight of the monaners.
Buffering agents, preferably phosphoric acid, sodiwm bicarbonate,
potassiun bicarbonate, sodium pyrophospha~e, potassiun pyrophosphate,
sodium phosphate, and sodium acetate may be used. The amount used is
preferably 0-5% by weight based on the total weight of the monomer(s).
The resulting polymers are dispersed in water ~hus fonmLng an
emulsion. The preferred particle size is 0.1-1 micron. The polymer
content (i.e., solids) in the emulsion is preferably 20-70~ by weight.
m e Tg of the acrylabe polymers is controlled by ~he carbon chain length
of ~he alkyl group (i.eO~ R ) in the acryla~e or methacrylate monamer.
The polymer should have a theoretical Tg below 10C, preferably below O~C
and most preferably -10C or below. m e acrylate polymers become brittle
~ 9L297~9
when their Tg is over 10C and, consequently, the flexibility of the
cement mortar is not improved. Ihus, it is necessary to keep the Tg below
10C.
Howeverf acrylate or methacrylate polymers having a Tg above 10~C can
S ke used ir sufficient plasticiæer iS added so that the apparent Tg of the
plasticized polymer composition is lowered to ~elow 10C. For the
purposes herein, thes2 plasticized aqueous polymer emulsions are
considered the equivalent of the non-plasticized polymer emulsions
containing polymers ~a~ing the required Tg. The plasticizer can ~e added
at the same time the raw materials are charged to the reactor or can be
added after the po~ymerization reaction has ~een completed. The pre~erred
plasticizers i~clude dibutyl phthalate, dioctyl phthalate, trLmethyl penta
diol mono-iso-butyrate, trimethyl penta diol di-iso-butyrate, and butyl
carbitol. The amount of plasticizer used is below 20% by weight, based an
the total weight of the polymer. It is preferable to minimize the amount
used.
With respect to the iower limit for the Tg of the polymers, if it is
below -40C, the main chain of the the polymer becomes too soft and
sufficient mechanical strength is not obtained even after ~he curLng has
taken pl~ oe . ~ence, the preerred lower limit for the Tg is -40C, more
preferably -30C.
The cement admixture herein is manuEactured by mixlng the aqueous
polymer emulsion, cement, and~ if necessary, other a~ditives. All kno~n
cements are suitable for use herein, i.e., Portland cement, rapid
hardening cement, ultra rapid hardening cementt aluminum cement, jet
cement, Portland blast furnace cement, Pozzolan cem~nt, sulfate resistant
cement and white Portland cement. Fillers are used when necessary, and
c, .,
~Z97Z~9
g
the preferred fillers include silica sand, crushed sand, blast furnace
slag sand, sea sand, Pe~lite, calcium carbonate, asbestos, al~ali-
resistant glass fiber, steel fiber, carbon fiber, fly ash, titanium
dioxide, and iron ore sand. The addition of a defoamer makes it possible
to obtain high density cement mortars. The amount of defoamer used is
preferably 0 5%, based on the aqueous emulsion. If a pigment is desired,
iron oxide red and carbon black are preferred.
Typical cement mixing methods are suitable for mixing the above
aqueous polymer emulsion and the cement. For example, the cement,
emulsion, and necessary fillers (depending upon the end use) are mixed in
a conventional mixer such as an electric mixer, a paint disperser, or a
mortar mixer. In this case, the emulsion can be diluted previously with
part or all of the water to be adde~ as mixing water for the cement. m e
amount of polymer emulsion used should ~e sufficient to provide 1-200% of
polymer solids based on the cement solids weig~t. The appropriate mixing
ratio i5 selected within this range according t~ the use for the cement
mortar composition. For example, when the adhesion i~ to be increased,
1-40%, preferably 5-25%, is appropriate. ~hen flexibility is to be
provided, 25-200~, preferably 40-100%, i5 appropriate. E~ren though the
mixing of the polymer emulsion and cement is carried out at room
temperature, the curing reaction does not ~ake place immediately, but
follows the rate of the cement hydration reaction.
In the typical cement mortar the ratio of cement to ~and to polymer
solids is 1 to 0.5-4.0 to 0.05-0.25, whereas in the typical oement paint
the ratio is 1 to 0-1 to 0.1-1. The resulting cement admixtures are
suitable for use on various types of adherent surfaces, such as concrete
structural walls, concre~e floors, waterproofing cement mortars, elastic
~2972~9
-- 10
c~nent coatings, weathered ceramic tile surfaces, steel floors, or steel
pipe surfaces. They are also suitable for joint sealing of concrete,
autoclaved light weight concrete, and ceramic tile. They may be applied
in the same manner as the usual Gement finishing methods, e.g., by the use
of trowel, brush, or spray gun. m e amount applied will depend upon the
use, typically a thick coating (1-50mm) is applied when the cement is used
as a mortar and thin coating (1-2mm) is applied when the cement is used as
a paint. m e curing of the cement admixture is carried out in air or in
moist air.
When the cement admixture herein is coated on the adherent, the water
in the cement admixture is decreased by hydration of the cement, by
evaporation, and even by beiny absorbed into the adherent when the
adherent has water absorbing capability. Upon loss of water the polymer
particles, c~ment particles, and option~l fillers become more intimately
in contact with each other. qhe acrylate polymers herein have many
cationic groups on the surface of the acrylate polymer particles. me
particles are more strongly cationically charged than those polymers
containing added cationic surfactants or protective colloids, as well as
those cationlc polymers containing no alkaline cur~ble groups (e.g.,
alkylaminoethylmethacrylate). m e particles, therefore, are absorbed and
fuse~ more effectively with ~ anionir c~ment partid es an~ fillers.
The cemRnt admixture here m provides flexibilit~ and good adhesion
which is not reduced by changes in temperature. Because the polymer has
a Tg of below 10C it is rather soft, and the hardened cement shows
ex oe llent flexibility, not only at ordinary temperatures, but also at low
temperatures.
~29~2~
In the examples which follow, the parts are by weight, the Brabender
viscosity is determined at 30C, and the réported ~9 values are
theoretical (i.e., calculated) values rather than actual I~ values.
EXAMPLE I
S This example descri~es the preparation of an aqueous emulsion of an
acrylate polymer (MMA/2-E~) containing an alkaline-curable cationic
quaternary ammonium salt monomer. It compares the performance of a cement
mortar containing this polymer emulsion with cement mor'cars containing
aqueous emulsions of comparative acrylate resins.
. Par_A - Alkaline-Curable Acrylate Emulsion
The following were charged to a 2 liter reactor equipped with an
anchor-shaped agitator:
Initial Char~ Parts
Polyoxyethylene nonylphenol. (20 moles EO~) 5
15 Sodium hydrogen phosphate 0.5
~mmonium persulfabe 0.5
Hydroxyethyl cellulose (as a 2% solution having 3
a viscosity of 10 cps.)
Water 100
20 * E0-ethylene oxide
Total 109
Monomer Charge Parts
Methyl methacrylate (MMA) 32
2-Ethylhexyl acrylate ~2-EHA) 65
25 Nitrate salt of DimethyIaminopropyl methacrylateJ 3.3
Epichlorohydrin adduct (DMAPMA/Epi ' ~O3) (90% soln.)
~00.3
~2~72J ~
T~ initial aqueous solution Wa5 charged to the reactor, heated to 75C,
and maintained at this temperature while the monomer charge was slowly
added over 3 hours. After the slow addition was completed, heating was
continued for 1 hr. The emulsion had a solids content of 51%, viscosity
of 3500 cps., and pH of 2.2. The Tg of the polymer was -14C. Using
this alkaline-curable cationic acrylate polymer emulsion, a cement mortar
was formulated as follows:
Parts
Portland cement 100
Standard sand 300
Acrylate emulsion 39.2 (20 as polymer solids)
Defoamer ~VPCO NX~*
Water 45
It was poured into a 4.5 x 4.5 x 0.5 cm. frame placed on top of a 7.5 x
7.5 x 0.5 cm. glazed semi-porcelin tile and air cured for three weeks
under standard conditions ~20C, 65~ relative humidity).
art B ~_Comparative Acrylate Emulsion~s
An emulsion (B-l) of a commercially available cationic acrylate
polymer, i.e., dimethylaminoethyl methacrylate/2-ethylhexyl acrylate/
methyl methacrylate ~DMAEMA/2-EHA/MM~), was used in place of the polymer
emulsion of Part A. The amount used was sufficient to provide 20 parts by
weight of polymer solids. The emulsion had a solids oontent of 40%,
viscosity of 150 cps., and p~ of 5.4. The qg of the polymer was -5C.
An emulsion (B-2) of a commeroially available anionic acrylate
polymer, i.e., acrylic acid/2~ethylhexyl acrylate/styrene (AAj2-EHA/St)
was used in place of the polymer emulsion of Part A. It was used in an
amount sufficient to provide 20 parts by weight of polymer solids. m e
_ emulsion had a solids content of 58%~ viscosity of 700 cps., and pH of 8.
The Tg of the polymer was -20~C.
*Trade Mark
~72~9
- 13 -
The tensile butt adhesive strength of the three assemblies was
measured using a Kenken type tester. ~ne results are shown in Table 1.
Table I
Polymer Adh~sive Breaking Behavior (~ failure)
5 Emulsion (Xg./cm. ) Stren~th InterfaceMortar or adherent
Part A 6.8 0 100
Part 8-1* 3.1 90 10
Part B-2* 2.6 100 0
*Comparative
The results show that the cement mortar containing tne alkaline
curable quarternary am~onium salt monomer had excellent adhesion. The
comparative acrylate polymers which had a Tg below 10C and one of which
was cationic, showed much poorer adhesion. The results also show that the
cement mortar containing the alkaline-curable monomer failed in cohesive
strength (i.e., failed in the mortar or adherent) rather than at t`ne
interface with the adherent, ~hereas the cement mortar containing the
camparative acrylate polymers failed in adhesive strength (i.e., failed at
the interface).
.,
EX~MPLE II
The polymerization was carried out as in Example I except that the
initial charge was as shown below and the monomer charge was as indicated
in Table II.
Initial Char~ Pa
Polyoxyethylene octylphenol (15 moles EO) 5.0
Polyoxyethylene octylphenol (35 moles EO) 5.0
Potassium persulfate 0.5
Sodium hydrogen phosphate 1.0
Water 100
Total 111.5
*Trade Ma~k
~297%: L9
Table II
Properties of
No. ~onom_r Composition (parts) _ Emulsion Pol~;mer DMAEMA/Epi. Add~ct Solids Visc, ~ Tg
(90% Chloride soln.) MMA BA 2-EHA St (%) ~ (cps.) ( C)
2* 0 30 70 51.5 450 2.7 -11
3 0.55 29.5 70 51.4 430 2.5 -13
4 1.1 29.0 70 51.3 ~40 2.6 -14
3 3 27 0 70 50.9 ~60 2.7 -14
6 8 8 22 0 70 50.8 550 2.5 -15
7 11.0 20.0 70 50.6 300 2.7 ~16
8 15.6 16.0 70 50.6 290 2.6 -16
9 4 4 70 26 51.6 610 2.6 -12
10** 5 5 47 48 50.9 ~20 2.7 +13
1511** 5.5 5 90 5~.7 490 2.S -48
* Comparative - no alkaline-curable monomer
**Comparative - outside Tg range
The DMAEMA/Epi adduct i5 an adduct of dimethylaminoethyl m~thacrylate and
epichlorohydrin.
~sing the resulting emulsions, cement mortars were formulated as
follows:
Par~
Rapid hardening cement 100
Silica sand ~No. 6) 100
Silica sand (No. 7) 100
Silica sand (No. 8) . 100
Polymer emulsion 20 (polymer solids)
Defoamer 0.5
Water 50
The mortars were poured onto four different adherents and cured for tw~
weeks under the standard conditions. The adherents and their dimensions
were as follows:
SS41 Steel (6.0 X 9.0 X 0~9 cm)
Plywood lauan (7.5 X 7.5 X 0.9 om)
Semi-porcelain tile (7.5 X 7.5 X 0.5 om)
Cement mortar brick (7.0 X 7.0 X 2.0 cm)
qhe adhesive test results are shown in qable III. Ihe assemblies
other than the plywood assembly were sub~ected to an aging test which
involved the following cycles: submersion in water for 2 days at room
temperature followed by drying for 2 days at 80C; after 5 such cycles the
~Z97Z~9
- 15
ass~mbly was cured for 1 week under standard con~itions. The sample
designated No. 12 was obtained by modifyinq the polymer emulsion
designated ~o. 10 with 5% of the plasticizer dibutyl phthalate to lower
the apparent Tg of the emulsion from ~13 to 0C.
TABLE III
No. _ Steel Semi rcelain Cement mortarPl ~ ood
Alr- After PO Air- After Air- After
Cured Aain Cured A~inq Cured AgingCured a4ing
2* 5.7 8.3 4.1 1.2 5.~ 8.6 4.0
3 10.6 16.7 6.0 5.6 11.715.6 8.6
4 12.2 17.8 6.4 5.9 13.217.2 9.0
13.0 18.0 7.6 6.1 13.918.7 9.2 --
6 14.1 19.2 7.2 5.8 15.220.6 9.5
7 13.2 19.0 8.0 6.0 14.918.6 8.0 --
8 9.0 4.4 6.4 3.1 16.6 9.0 8.8
9 14.9 18.6 6.8 5.9 13.418.1 8.6
10** 16.8 8.0 7.8 2.4 19.2 9.3 8.8
11** 10.1 12.0 5.2 5.0 11.110.5 9.0 --
12*** 14.4 13.9 7.0 6.0 18.217.2 8.1
* Comparative - no alkaline-curable monaner
** Comparative - outside Ig range
~**Same as No. 10 but modified with plasticizer
m e results show that the cement a~nixtures containing ~he alkaline-
curable cationic quaternary ammonium salt monomers had excellent adhesion
to all adherents. m e comparative cement admixture ~see No. 2), in which
a typical acrylate polymer emulsion i.e., an emulsion containiny a polymer
with no alkaline-curable polymer, was used showed both poor initial
adhesion and poor adhesion after aging. m e results also show that even
when the ~lk2line-curable cationic quaternary ammonium salt nomer was
used, if t~e Ig is abcve 10C (see Nb. 10), the adhesion after aging wzs
unsatisfactory. When this p~lymer was used with the plasticizer, it was
satisfactory (see No. 12). The results further show that an alkali-
~2~729 ~
c~rable polymer with too low a Tg was inferior to the hi~her qg polymers
(see No. 11). The appropriate Ig range for the polymer is thus
demonstrated.
EX~MPLE Ill
The polymerizations were carried out as in Example II using the
monomers shown in Table IV.
~B~E IV
Monomer Composition No.
13 14* 15* 16* 17*
_
Nitrate Salt of Dimethyl-
aminoethyl methacrylate/
Epichlorohydrin adduct
(DMAEMA/Epi . N~3). 3.3 -- --
(90% Nitrate soln.)
Methyl methacrylate (MMA) 27 27 25 27 26
2-Ethylhexyl acrylate 70 70 70 70 70
(2-EHA)
Other monomer** ~ 3 AA 5 GMA 3 DMAE~ 4 DMAPMhm
.
_ Pro~erties of the emulslon and polymer
Solids ~) 50.5 50.8 50.7 51.0 50.7
Viscosity (cps.) 300 810 240 280 250
pH 2.6 2.4 2.5 2.8 2.7
Tg tC) 23 -23 -25 -22 -24
* Comparative
**AA is acrylic acid; GMA is glycidyl methacrylate; DMAE~ is
dimethylaminoethyl acrylate: DMAPMAm is dimethylaminopropyl
~ethacryla~mide.
Using the résulting polymer emulsions, the following c~ment
admixtures tdesignated A and B) were formulated:
(A) C~ment composition same as in Example II
Parts
(B) ~hite Portland cement 100
Calcium Carbonate 50
Polymer emulsion100 (polymer solids)
Methyl oellulose 0.2
Defoamer 3
Water appropriate amount
~Z972~g
- 17
~ e cernent admixt~res were thoroughly agitated and cement paints were
made. Films (1 mm thick) were formed by immediately casting the paint on
a Teflon*plastic plate. After curing for one month, the cement films were
tested for tensile strength (m2ximum point) and elongation ( % at break)
at -10, 20, and 50C using an Instron tester at a tensile speed of 200
mm/min.
The results are shown in Tables V and VI. The emulsion designated
No. 18 was prepared using a cationic surfactant in place of the alkaline-
curable cationic quaternary ammonium salt monomer and the polymerization
was carried out using methyl methacrylate/2-ethylhexyl acrylate (35/65) as
the monomers and lauryltrimethylammonium chloride as the surfactant. ~The
polymerization was carried out as in Example I.
TABLE V - Adhesion ~k~/om2) of Cement A
' Polymer
~mulsion ~b.
.
herent Test Conditions13 14* 15* 16* 17* 18*
Steel Air-Cured 12.712.0 13.0 11.6 13.2
After ~ging 17.213.6 8.B 9.0 8.8
Semi porcelain Air-Cured 5.9 4.3 3.0 4.0 4.2
tile After ~ging 5.2 2.7 2.0 3.0 3.3
Cement mortar Air-Cured 12.6 11.4 12.2 14.2 13.2
After Aging 15.416.3 17.2 9~3 8.8
Plywood (Lauan) Air-Cured 7~7 5.4 5.6 5.0 4.3 -- -
After Aging ~
I~BL~_VI Properties of Cement Film B
Emulsion No.
13 14* 15* 16* 17* 18*
Tensile strength (kg.~om.2) -10C 42.6 125 110 101 132 90.3
20C 12.6 15.213.6 9.0 10.6 5.0
30 50C 5.0 3.0 2.5 3.4 3.7 1.9
*Trade Mark
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TABLE VI Properties of Cement Film B (cont'd)
Emulsion No.
13 14* 15* 16* 17* 18*
~aximum elongation (~) -10C 220 40 30 105 90 105
20C 920 450 400 800 7201100
50~C 1940 2~10 22002900 25002760
*Comparative
The results show that the cement admixture containing the alkaline-
curable cationic quaternary ammonium salt moncmer (No~ 13) was superior
not only in adhesion to various adherents but also in the balance of
tensile strength and elongation in comparison to the typical cement
compounds (Nos. 14-18). Additionally, the variation in properties within
the temperature range of -10C to +50C are slight, and accordingly the
composition can be applied over a wide range of temperatures. m e typical
cement admixtures showed a marked decrea æ in their perfonmance after
aging, whereas the cement admixture herein (No. 13) maintained the initial
adhesion level. It is believed this difference is due t~ the flexibility
of this cement mort~r which allow~ for temperat~re variation. Typical
cement mortars are not flexible.
~XaMPi~ VI
The polymerization was carried out as in Example I except that the
reaction temperature was 70-75C and the slow addition time was 4 hours.
The charges are described below:
Initial Char~ Parts
Polyoxyethylene nonylphenol (20 moles EO) 6.0
Ammonium persulfate 0.4
Sodium dihydrogen phosphate 0.5
Water 100
Total 106.9
`` ~Z97~
_ 19 _
Mon~ner Charge Parts
~thyl methacrylate (~ ) 10
Styrene (St) 15
2-Ethylhexyl acrylate ( 2-EHA ) 42
~thyl acrylate (EA) 30
Nitrate salt of Dimethyaminopropyl
methacrylamide/Epichlorohydrin 4.3
Adduct (70~ Nitrate Soln.
(DMAPMA~Epi. NO3)
Total 101.3
The emulsion had a solids content of 50.2~, viscosity of 400 cps.,
and pH of 3.1. The polymer h~d a Tg of -14-C~
~ sing the above emulsion, a cement mortar was formulated as follows:
Rapid hardening cement 100
Silica sand (No. 7) 100
Silica sand (No. 8) 100
Silica sand (No. 9) 100
Resin emulsion 30 (as polymer solids)
Oefoamer 2
Water Appropriate amount
The flow value (detenmined according to ASTM C~30-55T) of the final
cem;ent mortar was adjusted to 170 mm~ It was poured onto a 5 year old
epoxy coated floor. It was smoothed to a thickness of 2-5 mm by troweling
and cured or 1 week in air. lhe adhesion of the Gement mortar to the
surface was 8.4 kg/cm2 after 7 day~ curing. Cements containing the
comparative p~lymer em~sio~s B-1 and B-2 of Example I were also applied;
their adhesion was poor (both 0 kg/cm2).
EX~MPLE VII
The pol~merization was carried out as in Example I using the
following:
Initial Charge Parts
Polyoxyethylene nonyl~henol (25 moles EO) 7.0
Potassium persulfate 0.6
Water 70
Total 77.6
,
~2972~L~
- 20 -
Monomer Charge Parts
B~tyl methacrylate (a~A) 15
Styrene (St) 10
Ethyl acrylate (EA) 25
Butyl acrylate (BA) 45
Chloride salt of DLmethylaminoethyl methacrylate
/Epichlorohydrin adduct 5.5
(DMAEMA~Epi . Cl) (90~ soln.)
Total 100.5
The emulsion had a solids content of 59.1~, viscosity of 1520 cps.,
and pH of 2.3. The polymer had a Tg of -18DC.
~sin~ the above polymer emulsion, the following cement mortar was
formulated:
Rapid hardening cement 100
Silica sand (No.'7) 100
Polymer emulsion 50 (polymer solids)
Defoamer 3
Water appropriate amount
The flow value of the cement mortar wa~s adjuqted to 200 mm. The
fresh cement mortar was patched on the h~llow places of asphalt mixed with
concrete usi~ a trowel and the surfaoe was flattened. The cement mortar
was cured for 1 week. A urethane coating for flooring was coated on the
cement mortar with the thickness of the coating being S mm. ~fter 1 year,
the constructed portion were examined thoroughly; no degradation was
detected. Ihe adhesion to both the asphalt concrete resin an~ urethane
resin was satisfactory. SLmilar evaluations were carried out with the
comparative resins (B-1 an~ B-2 of Example I)~ me results were poor.
The cement mortar swelled due to the absorbtion of water from the under
layer. lhe surface of the coated urethane becane uneven after 6 months.
~Z~7~
- 21 -
Example VIII (comparative)
~ nis example sho~ th3t the lower alXyl acrylates (C1 and C2) are
poor in hydrolytic stability. A ethyl acrylate/2-ethylhexyl acrylate/dim-
ethylaminopropyl methacrylamide/epichlorohydrin adduct as the chloride
S salt (87.7/9.7/2.6) having a Tg of -28 was evaluated. A butyl
acrylate/methyl methacrylate~acrylic acid (50/49/1) having a Tg of +2C
was also evaluated. The film weight minus loss (%) after immersion in
alkali i5 shown belo~.
Polymer Days Inmersion
~ 5 12 19 33 ~7
EA/2-EHA4DMAPMA.EPI adduct
In saturated cement solutlon* 1.1 1.7 1.8 2.3 2.5 2.8-
In 5~ ~aOH solution 0.7 1.Ç 1.8 2.2 3.4 4.4
~AA
In saturated cement solution* 0.6 1.1 1.5 2.0 2.2 2.2
In 5~ NaOH solution 0.2 1.1 1.5 2.0 2.2 2.2
*about pH 12
The resulks show that the butyl acrylate-based film sho~ed better alkali-
stability.
Now that the preferred embodiments of the invention have been
described in detail, various modifications and improvements thereon will
become readily apparent to those skilled in the art. A~cordingly, the
spirit and scope of the invention are to be limit~d only by the appended
claims and not by the foregoing specification.
