Aqueous dispersions of synthetic resins, their use as binders in adhesive compositions, and adhesive compositions obtained

Aqueous dispersions containing a mixture of 20 to 80% by weight of a latex of a copolymer A of butadiene, styrene and at least one unsaturated carboxylic acid, and 80 to 20% by weight of latex of a copolymer B of styrene, an alkyl acrylate and, if appropriate, at least one unsaturated carboxylic acid. The dispersions can be used as binders for the preparation of adhesive compositions suitable for joining or gluing two or more elements, and particularly suitable when at least one of the elements consists of a material which is difficult to glue, such as polyvinyl chloride.

The present invention relates to aqueous dispersions of mixtures of 
synthetic resins, to their use as binders in adhesive compositions 
suitable for joining or gluing two or more elements, and particularly 
suitable when at least one of the elements consists of a material which is 
difficult to glue, such as polyvinyl chloride, and also to the adhesive 
compositions obtained. 
It is known that the joining or gluing of various materials such as textile 
fibers, imitation leather, cardboard and the like to a polyvinyl chloride 
substrate, or the gluing of coverings with a polyvinyl chloride backing 
onto a floor or wall, is particularly difficult. The commercial glues 
capable of solving this problem include particularly expensive adhesive 
compositions based on aqueous dispersions of acrylic acid ester polymers, 
as well as glues containing organic solvents, which raise health and 
safety problems because of the risk to the health of users who inhale the 
solvent vapors and because of the flammability of the organic solvents. 
The inventor has developed aqueous dispersions of mixtures of synthetic 
resins which can be used as binders to ensure adhesion between any 
material and a material which is difficult to glue, such as vinyl chloride 
polymers or copolymers, without exhibiting the disadvantages mentioned 
above. 
The present invention therefore relates, by way of new industrial products, 
to aqueous dispersions of mixtures of synthetic resins which can be used 
as binders in adhesive compositions. 
According to the invention, the aqueous dispersions comprising a mixture of 
20 to 80% by weight of a latex of a copolymer A of butadiene, styrene and 
at least one ethylenically unsaturated carboxylic acid, and 80 to 20% by 
weight of a latex of a copolymer B of styrene, an alkyl acrylate, in which 
the alkyl is C.sub.1 to C.sub.8, and, optionally, at least one 
ethylenically unsaturated carboxylic acid. 
The copolymer A preferably comprises, by weight of solids in the latex of 
A, 40 to 70% of butadiene, 29 to 55% of styrene and 1 to 10% of at least 
one ethylenically unsaturated carboxylic acid, and more preferably, 45 to 
58% of butadiene, 40 to 50% of styrene and 2 to 5% of at least one 
ethylenically unsaturated carboxylic acid. 
The copolymer B preferably comprises, by weight of solids in the latex of 
B, 30 to 60% styrene, 40 to 70% of alkyl acrylate and 0 to 10% of at least 
one ethylenically unsaturated carboxylic acid, and more preferably, 35 to 
45% of styrene, 50 to 60% of alkyl acrylate in which the alkyl is C.sub.2 
to C.sub.4, and 1 to 5% of at least one ethylenically unsaturated 
carboxylic acid. 
Representative ethylenically unsaturated carboxylic acids forming part of 
the composition of the copolymer A and, optionally, of the copolymer B, 
include acrylic, methacrylic, crotonic, maleic, fumaric, itaconic, 
mesaconic and glutaconic acids and chlorinated derivatives of these acids, 
such as chloroacrylic, chloromethacrylic, chloromaleic, chlorofumaric and 
chloroitaconic acids, or a mixture of at least two of these acids. 
According to a preferred embodiment of the invention, the aqueous 
dispersions consist essentially of a mixture of 40 to 60% by weight of the 
latex of copolymer A and 60 to 40% by weight of the latex of copolymer B. 
Before being mixed, the latex of copolymer A and the latex of copolymer B 
each contain from 40 to 70%, preferably, from 50 to 60%, by weight of 
solids. The mixture of the latices of A and B contains from 40 to 70%, 
preferably, from 50 to 60%, by weight of solids. 
The latex of copolymer A and the latex of copolymer B can be prepared by 
any of the aqueous emulsion polymerization processes. 
Once the latices of A and B have been prepared, they are agitated together, 
at 10.degree. to 80.degree. C., preferably, between 20.degree. and 
30.degree. C., and in the proportions indicated above. 
The present invention also relates to the use of the aqueous dispersions 
described above as binders in adhesive compositions suitable for joining 
or gluing two or more elements, at least one of which consists of a 
material which is difficult to glue. The present invention also relates to 
the adhesive compositions obtained, which are particularly advantageous 
for solving the problems of the adhesion of various materials to resins 
based on vinyl chloride polymers or copolymers. 
The adhesive compositions forming the subject of the invention can be used 
in different types of application, for example: 
for producing wall coverings by gluing a woven or non-woven decorative 
textile material to a cellular polyvinyl chloride backing (providing 
rigidity and sound insulation); 
for manufacturing floor coverings by coating a polyvinyl chloride wearing 
layer with a mixture of the latices A and B containing a high proportion 
of filler, and then drying; and 
for manufacturing tufted carpets with a cellular polyvinyl chloride 
backing, by coating the back of the tufted carpet with a mixture of 
latices A and B containing a high proportion of filler, drying and then 
coating with cellular polyvinyl chloride. 
In particular, the adhesive compositions are advantageous for manufacturing 
floor or wall coverings known under the name "embossed expanded vinyl" and 
obtained by coating or calendering polyvinyl chloride or vinyl 
chloride/vinyl acetate copolymer onto a fibrous substrate produced 
beforehand by a papermaking process, a melt process (spunbonded) or a 
textile process. The adhesive compositions according to the invention are 
extremely suitable for effecting adhesion between the two constituent 
parts. 
The adhesive compositions according to the invention are also particularly 
suitable for gluing floor coverings having a vinyl chloride polymer or 
copolymer backing to a floor, such as a concrete floor. 
The adhesive compositions of the present invention comprise, as the binder, 
the aqueous dispersion described above, i.e, comprising a mixture of the 
latices A and B, together with at least one of the customary adjuvants 
present in glue formulations. The weight ratio of adjuvants/solids in the 
binder is generally between 1/1 and 10/1. 
The customary adjuvants are dispersing agents, protective colloids, 
plasticizers, coalescence agents, polar solvents, mineral fillers, 
crosslinking agents, thickeners and sticking agents. The nature and 
amounts of the adjuvants to be used depend on the particular application 
envisaged and can be determined by one of ordinary skill in the art 
without undue experimentation. 
Mineral fillers include, in particular, kaolin, calcium carbonate, gypsum, 
silica and talc, taken separately or as a mixture of at least two of these 
compounds. The size of the filler particles is generally between 5 and 100 
.mu.m, the average particle diameter being less than 50 .mu.m, preferably, 
from 5 to 15 .mu.m. 
Colophony is a customary sticking agent. 
Representative dispersing agents include tetrasodium pyrophosphate, sodium 
hexametaphosphate and low molecular weight polyacrylates. 
The plasticizers, coalescence agents, crosslinking agents thickeners, 
protective colloids, polar solvents and other customary adjuvants are 
chosen from amongst those normally used in glue formulation, and include 
butyl phthalate, dioctyl phthalate, white spirit, oil of turpentine, 
carboxymethylcellulose, alkali metal polyacrylates, glyoxal and 
phenol/formaldehyde resins. 
The adhesive compositions for gluing floor coverings to concrete can 
advantageously contain, in particular: an amount of mineral fillers 
corresponding to a weight ratio of mineral fillers/solids in the binder of 
between 2/1 and 4/1; an amount of colophony corresponding to a weight 
ratio of colophony/binder of between 0.2/1 and 0.4/1; and, optionally, a 
minimal proportion of polar solvents, coalescence agent and plasticizer 
corresponding to a weight ratio of solvent+coalescence 
agent+plasticizer/solids in the binder of between 0.1/1 ad 0.3/1. 
As physical properties, the adhesive compositions for gluing floor 
coverings to concrete advantageously have a pH of less than 8, preferably 
from 4 to 7 or very close to 7; a viscosity of 5,000 to 100,000 mPa.s, 
preferably 15,000 to 100,000 mPa.s and more preferably 15,000 to 60,000 
mPa.s; and a solids content, measured according to French Standard Test 
Method T 51 054 (105.degree. C., 2 hours) of up to 90%. 
The following examples illustrate, but do not limit, the invention. In 
these examples, to evaluate the quality of the glue bond, a series of 
tests was carried out on floor coverings with backings made of different 
materials. The tests are conducted as follows: 
(1) Peel strength test at 20.degree. C. and at an angle of 180.degree.: The 
purpose of this test is to measure the strength of the glue bonds. A 
fibrocement base board of dimensions 7.5.times.20 cm, finished with a 
coating of ARDIT and containing the adjuvant IBO (these two registered 
trademarks identify products manufactured by Weber and Broutin-77170 
SERVON, France), is dried for 24 hours at 20.degree. C. Unless indicated 
otherwise, the remainder of the operations are carried out in a room 
conditioned at 20.degree. C. and 65% relative humidity. 
A serrated doctor blade (model from Weber and Broutin) is used to coat five 
fibrocement base boards with 350-400 g/m.sup.2 of the glue to be tested. 
After 2 minutes, the five base boards and five identical samples of floor 
covering, cut lengthwise into strips to give 5.times.45 cm test pieces and 
coated, using the serrated doctor blade, with glue over an area of 
(5.times.15) cm.sup.2, are placed together simultaneously. These five 
assemblies are immediately stacked together and a pressure of 25 
g/cm.sup.2 is applied for 10 minutes to the surface of the top test piece 
of the stack. 
The measurement of the peel strength of the glue joint at an angle of 
180.degree. is carried out by means of a tensile tester with jaws moving 
at a speed of 100 mm/minute. 
The peel forces are measured on: 
five test pieces glued to the five base boards, as described above, and 
conditioned for seven days at 20.degree. C. and 65% relative humidity; and 
five other test pieces glued to five base boards also as described above, 
conditioned for seven days at 20.degree. C. and 65% relative humidity, 
then for five days at 55.degree. C. in a dry oven, and finally for one day 
at 20.degree. C. and 65% relative humidity. The results are expressed as 
daN/5 cm. 
(2) Determination of the sticking power (or grab) 
This is a method used in the art, which consists of producing a glue bond 
between a defined substrate and a defined covering, a so-called "cloth 
backing" board being applied to the covering in a given manner, before and 
after this covering has been placed on the said substrate coated with the 
glue to be tested. 
The procedure is as follows: a fibrocement base board of dimensions 
7.5.times.20 cm, finished with ARDIT and containing the adjuvant IBO 
(these two registered trademarks identify products manufactured by Weber 
and Broutin, 77170 SERVON, France), is dried for 24 hours at 20.degree. C. 
The remainder of the operations are carried out in a room conditioned at 
20.degree. C. and 65% relative humidity. 
A serrated doctor blade is used to coat the fibrocement base board with 
350-400 g/m.sup.2 of the glue to be tested. 
A sample of floor covering (identified by the registered trademark 
BICONFORT and manufactured by SOMMER S. A.-92200 NEUILLY, France) with a 
backing consisting of a mat of nonwoven polyester prepared by an adhesive 
melt process is cut lengthwise into an 80.times.100 mm test piece. This 
test piece is folded widthwise into two, in the middle, with outer face 
against outer face. Using a cloth backing board weighted with 2 kg of lead 
and having dimensions of 80.times.100 mm and a thickness of 20 mm, the 
fold in the covering test piece is crushed for 5 minutes. 
Five minutes after the deposition of glue on the fibrocement base board, 
the unfolded covering test piece is applied. 
The cloth backing board is then applied to this test piece for 10 seconds. 
If, in the next 20 seconds, the test piece is seen to lift up, the 
application of the cloth backing board to the test piece is repeated for 
10 seconds and it is observed again whether the sample lifts up. These two 
operations are repeated at most ten times. 
Other applications of floor covering test pieces are carried out under the 
same conditions, with waiting times before gluing being spaced apart by 
intervals of five minutes up to a maximum of 60 minutes. 
The number of times which the covering test piece lifts up is noted for a 
given waiting time before gluing. The sticking power is poor if the 
covering test piece lifts up 5 times: it is assigned a mark of 5. If the 
covering test piece lifts up 10 times, it is assigned a mark of 0. A good 
sticking power corresponds to a number of lifts of 0 to 3, with 0 
receiving a mark of 10 and 3 a mark of 7. 
(3) Gumming Time 
During the test for measurement of sticking power, it is noted that, after 
a certain waiting time between the application of the glue and the 
production of the glue bond, the sticking power reaches a constant maximum 
throughout the working time. This waiting time represents the value of the 
gumming time, which is, therefore, the interval of time elapsing between 
the moment when the glue is deposited and the moment when the sticking 
power is considered satisfactory. 
(4) Open Time 
The sticking power test is continued until there is no further visible 
transfer of the film of glue onto the backing of the covering test piece. 
One observes the time it takes for the glue to satisfactorily wet the 
backing of the covering test piece and obtain a good glue bond. The 
following marks are adopted for this purpose: 
5 corresponds to wetting the whole surface of the backing of the test 
piece, 
4 corresponds to wetting three-quarters of the surface of the backing of 
the test piece, 
3 corresponds to wetting half the surface of the backing of the test piece, 
2 corresponds to wetting a quarter of the surface of the backing of the 
test piece, 
1 corresponds to wetting only a few places on the surface of the backing of 
the test piece, and 
0 corresponds to zero wetting. 
In practice, the open time of the glue will be the time corresponding to 
the assignment of the mark of 1. 
(5) Working Time 
This is the open time minus the gumming time. 
(6) Determination of the solids content of the latices. 
This is accomplished according to French Standard Test Method T 51 054. 
(7) Determination of the Viscosity of the Glues The viscosity is measured 
by means of a Brookfield RVT instrument at 50 rpm.

EXAMPLE 1 
A latex of copolymer A with a solids content of 50% is prepared by the 
polymerization of butadiene, styrene, fumaric acid and acrylic acid in 
aqueous emulsion, the copolymer being composed of 48% by weight of 
butadiene units, 48% by weight of styrene units, 2% by weight of fumaric 
acid units and 2% by weight of acrylic acid units. 
A latex of copolymer B with a solids content of 50% is prepared by the 
polymerization of styrene, n-butyl acrylate and acrylic acid in aqueous 
emulsion, the copolymer being composed of 45% by weight of styrene units, 
50% by weight of n-butyl acrylate units and 5% by weight of acrylic acid 
units. 
60 parts by weight of the latex of copolymer A are mixed with 40 parts by 
weight of the latex of copolymer B, and the mixture is agitated to give a 
homogeneous composition. 
This mixture is incorporated as a binder into the ingredients indicated 
below to prepare a floor covering glue having the following composition in 
parts by weight: 
Mixture of latices of copolymer A and copolymer B with a solids content of 
50%: 200 
Silica (average particle diameter 40 .mu.m): 200 
Kaolin (average particle diameter about 2 .mu.m): 50 
Colophony: 56 
White spirit: 14 
Oil of turpentine: 10 
Dioctyl Phthalate: 4 
5% strength by weight solution of carboxymethylcellulose (marketed under 
the registered trademark Blanose R190 by NOVACEL): 2 
10% strength by weight aqueous solution of sodium hexametaphosphate: 10 
The weight ratio of colophony/latices=(56/200)=0.28. 
The weight ratio of white spirit+oil of turpentine+dioctyl phthalate/solids 
in binder=(28/100)=0.28. 
The weight ratio of mineral fillers/solids in binder=250/100=2.5. 
The viscosity of this glue, measured with a Brookfield RVT instrument at 50 
rpm, is 29,600 mPa.s. 
Various floor coverings with backings of different types were glued with 
the above glue. Table 1 summarizes the results of these gluing tests. 
TABLE 1 
______________________________________ 
Peel strength 
test after 
drying for 7 
days at 20.degree. C. 
and then for 5 
Peel strength test 
days at 55.degree. C. 
Nature of the back- 
after drying for 7 
and 1 day at 
ing of the floor 
days at 20.degree. C., in 
20.degree. C., in daN/5 
covering daN/5 cm cm 
______________________________________ 
Plasticized 2.65 5.4 
polyvinyl chloride 
*Taraflex "S" 
Styrene/butadiene 
Peeling of the foam 
Peeling of the 
rubber foam foam 
Polyurethane foam 
Peeling of the foam 
Peeling of the 
foam 
Cellular polyvinyl 
7.4 7.3 
chloride 
Cellular polyvinyl 
15.75 14.5 
chloride (another 
quality) 
Felt 9.5 15 
Felt (another quality) 
9.25 11.6 
Asbestos millboard 
Peeling of the mill- 
Peeling of the 
board millboard 
**Aiguellete Sommer 
6.3 8.25 
S600 
______________________________________ 
*Trademark Registered by B.A.T. (Tarare) 
**Trademark registered by SOMMER 
By way of comparison, gluing tests were carried out on a floor covering 
with a backing made of plasticized polyvinyl chloride (Taraflex "S" of 
Table 1), with glues of the same formulation as that indicated in Example 
1, except that the mixture of latices of the copolymer A and copolymer B 
was replaced in one case by the same amount of Latex A by itself, and in 
the other case by the same amount of Latex B by itself. 
Gluing was also tested with a glue of the same formulation, except that the 
mixture of latices A and B was replaced by a commercial poly-2-ethylhexyl 
acrylate latex having an initial glass transition temperature of 
-51.degree. C. 
Table 2 summarizes the results of the comparative tests. 
TABLE 2 
__________________________________________________________________________ 
Peel strength test 
Peel strength 
after drying for 7 
test after 
days at 20.degree. C. and 
Nature of the aqueous dispersion 
drying for 7 
then for 5 days at 
Fumaric 
Acrylic 
Buty days at 20.degree. C. 
55.degree. C. and 1 day 
Styrene Butadiene 
acid acid acrylate 
in daN/5 cm 
at 20.degree. C. in daN/5 
__________________________________________________________________________ 
cm 
Co- 
50 48 1 1 -- 0.4 0.1 
poly- 
48 48 2 2 -- 0.2 0.1 
mer 
50 48 1 1 -- 0 0 
Co- 
45 -- -- 5 50 0.4 0.3 
poly- 
36 -- -- 4 60 0.5 0.3 
mer 
45 -- -- 5 50 0.5 1.0 
B 45 -- -- 5 50 0.4 0.6 
40/60 mixture of copolymer A + copolymer B, 
2.65 5.4 
according to the invention 
Poly-2-ethylhexyl acrylate 2.0 1.4 
__________________________________________________________________________ 
The tests demonstrate that for a floor covering with a polyvinyl chloride 
backing, the binder mixture according to the invention makes it possible 
to obtain a glue bond having a peel strength considerably greater than 
that obtained with each of the constituent latices of the mixture used 
separately, or even with a glue based on poly 2-ethylhexyl acrylate. 
EXAMPLE 2 
The mixture of latices of Example 1 is used as a binder to prepare a floor 
covering glue having the following composition in parts by weight: 
Mixture of latices of Example 1 with a solids content of 50%: 200 
Ca carbonate (average particle diameter 5 .mu.m): 200 
Colophony: 56 
Oil of Turpentine: 14 
White spirit: 10 
Dioctyl phthalate: 4 
5% strength by weight solution of carboxymethylcellulose (marketed under 
the registered trademark Blanose R 190 by NOVACEL): 2.1 
10% strength by weight aqueous solution of sodium hexametaphosphate: 10 
Weight ratio of colophony/latices=(56/200)=0.28. 
Weight ratio of white spirit+oil of turpentine+dioctyl phthalate/solids in 
binder=(28/100)=0.28. 
Weight ratio of mineral filler/solids in binder=(200/100)=2. 
Viscosity of the glue, measured with a Brookfield RVT instrument at 50 
rpm=99,200 mPa.s. 
This glue was used on a floor covering having a backing made of plasticized 
polyvinyl chloride (Taraflex "S" used in Example 1). 
The results of peel strength tests are as follows: 
Peel strength after drying for two days at 20.degree. C., in daN/5 cm: 4.1 
Peel strength after drying for seven days at 20.degree. C. and then for 
five days at 55.degree. C. and one day at 20.degree. C., in daN/5 cm: 8.5 
EXAMPLE 3 
In the glue composition of Example 2, the 200 g of Ca carbonate particles 
having an average diameter of 5 .mu.m were replaced by 250 g of particles 
having an average diameter of 10 .mu.m. 
The viscosity of the glue, measured as in Example 2, was 60,200 mPa.s. 
Gluing tests were carried out with the floor covering of Example 2. 
The peel strength after drying for seven days at 20.degree. C. was 3.8 
daN/5 cm. 
The peel strength after drying for seven days at 20.degree. C. and then for 
five days at 55.degree. C. and one day at 20.degree. C. was 6.7 daN/5 cm. 
EXAMPLE 4 
In the glue composition used in Example 3, only 0.7 part of the 
carboxymethylcellulose solution was incorporated, instead of 2 parts. 
The viscosity of the glue, measured as in Example 3, was 19,200 mPa.s. 
After gluing tests on the covering of the previous example, it was found 
that the peel strength was 3.45 daN/5 cm after drying for seven days at 
20.degree. C. and 4.4 daN/5 cm after drying for a further five days at 
55.degree. C. and one day at 20.degree. C. 
Other test results obtained included: 
Gumming time in minutes: 5 
Open time in minutes: 35 
Working time in minutes: 30 
Sticking power good up to: 35 
EXAMPLE 5 
In the preparation of the glue composition of Example 4, the 
carboxymethylcellulose was replaced by 0.7 g of sodium polyacrylate 
marketed by PROTEX under the registered trademark Acrylron A 300. 
The viscosity of the glue, measured as in Example 4, was 23,200 mPa.s. 
The covering of Example 4 was subjected to gluing tests and the following 
results were obtained: 
Peel strength after drying for seven days at 20.degree. C.: 3.35 daN/5 cm 
and after further drying for seven days at 55.degree. C. and one day at 
20.degree. C.: 5.6 daN/5 cm 
Gumming time in minutes: 5 
Open time in minutes: 25 
Working time in minutes: 20 
Sticking power good up to: 20 minutes 
EXAMPLE 6 
The glue composition of Example 3 was used again but water was added to 
bring its viscosity to 52,000 mPa.s. 
The same gluing tests on the same covering as that of Example 3 gave the 
following results: 
Peel strength after drying for seven days at 20.degree. C.: 3.4 daN/5 cm 
and after further drying for five days at 55.degree. C. and one day at 
20.degree. C.: 6 daN/5 cm 
Gumming time in minutes: 5 
Open time in minutes: 20 
Working time in minutes: 15 
Sticking power good up to: 15 minutes