Note: Descriptions are shown in the official language in which they were submitted.
"~ 5'
CA 02336996 2001-O1-10
WO 00102972 1 PCT/EP99/04580
Mixture of Colophonium Resin and Wax
This invention rE;lates to a mixture of at least one rosin andlor a rosin
derivative and at least one wax, to its production and to its use in the
production of water-based adhesive dispersions.
Mixtures such as these are known. Thus, DE 195 31 849 describes
a solution of rosin in f;~tty acid esters. These solutions in liquid fatty
acid
esters are used for dispersion adhesives based on styrenelacrylate
copolymers. The adhesives obtained are suitable for bonding floor
coverings in place. ',
WO 97140117 relates to resin-containing dispersion adhesives
based on aqueous polymer dispersions. They contain a resin preparation
consisting of a mixture of 20 to 90% by weight of certain rosins and
derivatives thereof and 80 to 10% by weight of oils liquid at room
temperature. The liquid oils are either certain glycerol esters or certain
mixtures of saturated andlor unsaturated 04_22 fatty acids of vegetable
origin with monohydric C~_~2 alcohols.
Although the emission levels of these dispersion adhesives
containing the rosin solutions in liquid fatty acid esters are already low, a
further improvement i~; still desirable with a view to pushing the emission
levels below the odor threshold. At least the resin preparations (= mixtures
of rosin andlor rosin derivatives with wax) and the dispersion adhesives
should be substantially odorless. In addition, the production of the
dispersion adhesives, their storage and their use should of course be
unchanged or even improved. This applies in particular to such an
important property as i~~nitial tack in the wet state.
Accordingly, the problem addressed by the present invention was to
provide a rosin mixturE: which would improve the production and properties
of dispersion adhesives whilst at the same time avoiding all the
a
CA 02336996 2001-O1-10
WO 00/02972 2 PCTIEP99104580
disadvantages mentioned, particular emphasis being placed on the
substantial absence of odor and on high initial tack.
The solution is defined in the claims and consists essentially in the
use of waxes solid at room temperature as carrier medium for incorporating
the tackifying resins in the aqueous polymer dispersion. Accordingly, the
present invention relates to a mixture of at least one rosin andlor rosin
derivative and at least one wax, characterized in that the waxes individually
or in admixture with one another are solid at at least 15°C and
preferably at
20°C.
By "solid" is meant that the waxes, individually or in admixture, have
a defined shape and offer considerable resistance to any changes therein.
They do not have to be highly crystalline and, in general, are also
substantially amorphous. The waxes used in accordance with the invention
have a softening point (as determined by a modified ring-and-ball method,
see Examples) of at least 15°C and preferably at least 20°C.
They
generally change into a low-viscosity state above their softening point and,
in this respect, differ from resins, plastic compositions and metal soaps,
etc.
Substances which are "solid" in the sense of the above definition
and which also exhibit the other thermal and rheological properties are
referred to as "waxes". They are generally characterized by the following
properties: they are N;neadable, i.e. not glass-like, at 20°C. They
melt
without decomposition above 40°C and become low in viscosity between
50 and 90°C. Their melt is non-stringing. They are free from ash-
forming
compounds.
Actual examples from the class of natural waxes are candelilla wax,
carnauba wax, Japan wax, esparto grass wax, cork wax, guaruma wax,
rice oil wax, sugar cane wax, ouricury wax, montan wax, beeswax, shellac
wax, spermaceti, lanolin (wool wax), uropygial fat, ceresine, ozocerite
(earth wax), petrolatum, paraffin waxes and microwaxes. Actual examples
o r
' t
CA 02336996 2001-O1-10
WO 00/02972 3 PCT/EP99/04580
from the class of chemically modified waxes include montan ester waxes,
sassol waxes, hydrogenated jojoba waxes and partly oxidized polyethylene
waxes. Actual examples from the class of synthetic waxes are
polyalkylene waxes, ,polyethylene glycol waxes, ethylene/vinyl acetate
waxes, acrylate waxes, ethylenelacrylic acid copolymer waxes and
polybutylene glycol waxes.
Wax-like fatty compounds are preferred. The fatty compounds are
linear unmodified, modified and/or derivatized fatty acids or fatty alcohols
containing more than 6~ and more particularly 8 to 22 carbon atoms.
Among the fatty alcohols, the relatively high molecular weight, water-
insoluble fatty alcohols containing ca. 24 to 36 carbon atoms are also of
interest, above all in the form of esters with relatively high molecular
weight '',
fatty acids. Examples of wax alcohols are lignoceryl alcohol [1-
tetracosanol, H3C-(CI-12)22-CH2OH), cetyl alcohol (H3C-(CH2)2a-CH20H),
myristyl alcohol [1-triacontanol, H3C-(CH2)2$-CH20H] and melissyl alcohol
[1-hentriacontanol, H3C-(CH2)2s-CH20H]. Wool wax alcohols are also
understood to include triterpenoid and steroid alcohols.
Suitable fatty acids are likewise relatively high molecular weight fatty
acids containing at IE;ast 22 carbon atoms, for example behenic acid,
tetracosanoic acid, cerotic acid or melissic acid which - esterified with wax
alcohol, steroid or triterpene alcohols - are the principal constituents of
many vegetable and animal waxes.
The modification of the fatty acids is their partial or complete
hydrogenation. The derivatizationis an esterification,amidation
or
reduction of acid group, particularly a or complete
the more partial
esterification mono- to trihydricalcohols containingto 22 carbon
with 1
atoms or a partial or complete amidation with ammonia, primary and
secondary amines containing 1 to 22 carbon atoms. These derivatives are
preferred to the fatty acid or the fatty alcohol or fatty alcohol ether.
The modified fatty acids may be completely or partly esterified with
CA 02336996 2001-O1-10
WO 00/02972 4 PCT/EP99/04580
alcohols. By "alcohols" are meant hydroxyl derivatives of aliphatic and
alicyclic saturated, unsaturated andlor branched hydrocarbons. Both
mono- and dihydric alcohols or higher alcohols are suitable. Besides
monohydric alcohols, these include the low molecular weight chain
extending agents or crosslinking agents containing hydroxyl groups known
per se from polyurethane chemistry. Actual examples from the low
molecular weight range are methanol, ethanol, propanol, butanol, pentanol,
2-ethyl hexanol, 2-octanol, ethylene glycol, propylene glycol, trimethylene
glycol, tetramethylene glycol, 2,3-butylene glycol, hexamethylene diol,
octamethylene diol, nE:opentyl glycol, 1,4-bis-hydroxymethyl cyclohexane,
Guerbet alcohol, 2-methylpropane-1,3-diol, hexane-1,2,6-triol, glycerol,
trimethylol propane, trimethylol ethane, pentaerythritol, sorbitol, formitol,
methyl glycoside, butylene glycol, stearyl alcohol, behenyl alcohol, the
reduced dimer and trimer fatty acids and higher polyethylene,
polypropylene and polybutylene glycols. Monophenyl glycol or alcohols
derived from rosins, such as abietyl alcohol, may also be used for the
esterification. Instead of the alcohols, OH-containing tertiary amines may
also be used.
Suitable "amines" for the production of amides are
monoethanolamine, diethanolamine, ethylenediamine, hexamethylene
diamine, ammonia, etc.
The fatty alcoho~ls may be obtained by reduction of the acid group of
the modified fatty acids or by catalytic hydrogenation of the esters of the
modified fatty acids.
The fatty compounds according to the invention which emanate from ',
the hydrogenation arE; partly or completely hydrogenated derivatives of
unsaturated naturally occurring fatty acids, such as palmitoleic acid, oleic
acid, linolenic acid, ricinoleic acid and erucic acid or mixtures of these
fatty
acids. Fatty compounds of this type can be obtained not only by chemical
reaction, but also by physical separation processes, such as rollup
CA 02336996 2001-O1-10
y
WO 00/02972 5 PCT/EP99104580
separation or freezing out, from naturally occurring fatty acid mixtures or
fatty acid ester mixtures which naturally contain high levels of saturated
fatty acids such as, four example, animal fats or palm oil. Examples include
palmitic acid, palmitic acid methyl ester, palmitic acid triglyceride,
palmitoyl
alcohol, palmitic acid monoethanolamide, elaidic acid, elaidic acid methyl
ester, stearic acid, stearic acid methyl ester, stearyl alcohol, stearic acid
aryl ester, 12-hydroxystearic acid methyl ester, 12-hydroxystearyl alcohol,
hydrogenated castor oil, behenic acid methyl ester.
The modified fatty compounds may be produced either from the
modified fatty acids or by modification of corresponding fatty compounds.
Commercially available technical mixtures which, besides the
modified fatty compounds described above, contain other secondary
constituents known to the expert, such as short-chain, non-linear, branched
fatty acids containing i~Functional groups, are normally used. The secondary
constituents are partly unknown and may make up as much as 50% by
weight, depending on the particular modification and the starting material.
The modified fatty compounds may be both vegetable and animal in
origin.
The following products of Henkel KGaA are mentioned as examples:
Edenor ME ST 1 (stearic acidlpalmitic acid mixture), Edenor FHTi (stearic ',
acid, technical), Edenor C 16 92-94 (palmitic acid), Edenor C 18 98-100
(stearic acid), Edenor C 22 85 R (behenic acid), Edenor ME AS 16 (palmitic
acid methyl ester), Edenor Me Ti (stearic acid methyl ester, technical),
l_orol C 18 (stearyl alc:ohol), Stenol 1822 A (behenyl alcohol), Stenol 16-18
(palmityl/stearyl alcohol), Edenor NHTi (stearic acid triglyceride).
The following products of Unichema are mentioned as examples:
Uniwax 1750 (stearic acid amide), Uniwax 1760 (ethylene-bis-stearamide),
Estol 1482 (methyl stearate), Estol CEP (cetyl palmitate), Estol MEP
(methyl palmitate), Prifac 5902 (partly hydrogenated tallow fatty acid),
Prifac 2981 (stearic acid) and Pristerene 4913 (palmiticlstearic acid
v
t
CA 02336996 2001-O1-10
WO 00102972 6 PCT/EP99/04580
triglyceride).
Mixtures of Pri~;terene 4913 and Priolube 1451 and of Edenor FHTi
and Estol CEP are nnentioned as example of mixtures of commercially
available products.
The fatty compounds are substantially saturated or contain trans-
double bonds: they contain C-C double bonds in a concentration
corresponding to an iodine value of less than 100, more particularly less
than 75 and above all less than 50.
In order to improve the adhesive properties andlor the rheology of ',
the adhesives, up to '100% and preferably up to 50%, based on the solid
wax and depending on the type of polymers used, of plasticizers that do
not correspond to the invention, as described for example in WO 96!06897,
may also be used. Examples of such plasticizers are liquid fatty acid
esters, such as methyl laurate, isopropyl myristate, octyl caprylate,
epoxidized fatty compounds, such as epoxidized soybean oil, epoxidized
linseed oil, epoxystearic acid methyl ester, diepoxystearic acid methyl
ester, epoxystearic acid-2-ethyl hexyl ester, vernonia oil, epoxidized palm
kernel oil, esters of ghycerol such as, for example, triacetin,
caprylic/capric
acid triglyceride, rapeseed oil, soybean oil and castor oil. However,
standard petrochemical-based plasticizers known to the expert, such as
phthalic acid esters, monophenyl glycol, adipic acid esters, chloroparaffins,
polymeric plasticizers, benzoic acid esters, trimellitic acid esters and
citric
acid esters, may also be used.
The liquid plasvticizers additionally used may be added both to the
resin melt and - preferably - to the final adhesive formulation.
However, it is important that the mixture of wax and additional
plasticizer also have .a softening point of at least 15°C and
preferably at
least 20°C.
Rosin is the generic name for gum, wood and tall-oil rosins. These
rosins are resins of vegetable origin which exist as complex mixtures of so-
CA 02336996 2001-O1-10
2
WO 00/02972 7 PCT/EP99104580
called resin acids. Such natural resin acid mixtures consist essentially of
special unsaturated carboxylic acids with the empirical formula C2oH3oO2,
for example abietic acid, neoabietic acid, levopimaric acid, pimaric acid,
isopimaric acid, palustric acid etc., optionally with small amounts of
hydrogenated, dehydrogenated or oxidized resin acids and so-called
neutral substances, such as fatty acid esters, terpenes, terpene alcohols
and hydrocarbons.
Besides the rosin itself, chemically modified rosins with a softening
range or melting point of 15 to 130°C are also suitable as tackifying
resins.
These modified rosins are in particular rosin derivatives obtained by
isomerization, dimerization, polymerization, disproportionation or
hydrogenation andlor by homogeneous or mixed esterification with mono-,
di- or polyhydric alcohols, for example with methanol, ethylene glycol,
diethylene glycol, triethylene glycol, glycerol, pentaerythritol etc., and by
esterification of resin acid derivatives such as, for example, esters of
hydroabietyl alcohol with mono- or polyhydric alcohols. Paraformaldehyde-
modified rosins may allso be used.
The rosin or its derivative preferably has a softening range of 15 to
130°C and more particularly 15 to 95°C (ring-and-ball).
Preferred resins
are liquids of medium to high viscosity at room temperature or solids
melting at temperaturE;s of up to 120°C.
High initial tack and cohesion of the dispersion adhesives produced
in accordance with the invention can be achieved above all with resin
preparations of resins which are themselves solid and have a melting point
or softening range of 50 to 130°C. Resin preparations of resins which
are
themselves liquid or have a melting point or softening point of 25 to
50°C
give softer dispersion adhesives with good initial tack but relatively poor
cohesion. According to the invention, resin preparations with which the
tack and strength properties of the dispersion adhesives produced from
them can be adjustecl as required can be produced by selecting suitable
9
CA 02336996 2001-O1-10
WO 00/02972 8 PCT/EP99/04580
resins or by mixing resins with different melting points or softening ranges.
Other tackifier:;, above all hydrocarbon or phenolic resins or
terpenelphenol resins;, may be used instead of or preferably in addition to
the rosins. These resins may be used either individually or in the form of
mixtures; they are preferably used in a percentage by weight of 0 to 80%
by weight and more particularly 5 to 40% by weight in addition to the rosins.
Any reference fio "resins" in the following is meant to apply to at least
one of the resins described above.
According to the teaching of the present invention, resin
preparations in which the resin to wax ratio is as high as possible and
which have a viscosity at 20 to 100°C that still just allows them to be
handled, pumped and mixed lead to a higher initial tack and cohesion - for
the same percentage content in the dispersion adhesives produced from
them - than resin preparations with a relatively low resin-to-wax ratio.
Relatively low resin-to-wax ratios lead to resin preparations with a lower
viscosity and give softer dispersion adhesives with lower initial tack and
cohesion, but with a longer open time. Basically, compositions of 5 to 50%
by weight, more particularly 10 to 20% by weight of at least one wax and 95
to 50% by weight, more particularly 80 to 90% by weight of at least one
resin, based on the mixture of waxes and resins, are suitable. The most
suitable resin-to-wax ratios depend upon the nature of the resins and
waxes, upon the required viscosity of the resin preparation and upon the
required properties of the dispersion adhesive. They may readily be
determined by tests.
The mixture according to the invention may also contain auxiliaries,
for example to reducE: the viscosity of the resin solution or to improve its
compatibility with the polymer dispersion.
According to the teaching of the invention, the initial tack and
cohesion attainable in a dispersion adhesive increase with the amount of
resin preparation incorporated for the same resin-to-wax ratio providing the
i
CA 02336996 2001-O1-10
WO 00/02972 9 PCTlEP99/04580
resin preparation is selected from those of which the inherent tack and
inherent cohesion exceed those of the adhesive preparation to which the
resin preparation has not been added. Quantities of the resin preparation
in the dispersion adhEaive of 5 to 60% are suitable for the purposes of the
invention, quantities of 10 to 25% being preferred.
The resin prep;~rations according to the invention (= mixture of resin
and wax) are produced by introducing the wax into a heatable mixing
vessel and heating it to a temperature of at least 40°C and preferably
in the
range from 60 to 120"C. The resins are added in portions with stirring and
mixed in until a transparent mixture is formed. The resulting preparation
may then be heated with stirring for about 30 minutes to several hours to a
temperature of around 100°C in order to remove volatile ingredients,
for
example terpenes, from the rosins, optionally via a condenser. The solid
wax is preferably introduced into a heatable mixing vessel together with the
resin, heated to 60 to 90°C and stirred until a transparent mixture is
formed.
The mixed homogeneous resin preparation is preferably heated or
cooled with stirring to a temperature of 20 to 95°C and preferably to a
temperature of 75 to 85°C and is then immediately processed at
temperatures in that range or stored. The liquid resin preparation may
therefore be directly .added to and mixed with the polymer dispersion or
mixture of the other adhesive constituents introduced into another mixer.
However, it may also be cooled and reheated before dispersion or stored at
a temperature at which it remains liquid and pumpable.
The resin preparation according to the invention is preferably a
homogeneous mixturE; which is reflected in its transparency.
The resin prE:parations according to the invention satisfy the
requirements made of them to a large degree within the quantity ranges
according to the invention. They are homogeneously liquid and can be
adjusted to the viscosity required for handling at a temperature of 20 to
r
CA 02336996 2001-O1-10
WO 00102972 10 PCTIEP99104580
95°C. The resin preparations according to the invention may readily be
incorporated in dispersion preparations and surprisingly provide the
dispersion adhesives produced with them with initial tacks that can be
varied within wide limits. There is no evidence of any adverse effect on the
floor coverings bonded in place with the dispersion adhesives.
The liquid carrier media used in accordance with the invention do
not have a measurable vapor pressure so that the VOC emissions of the
resin preparation are largely confined to the emissions of the resins used.
The dispersion adhesives produced therewith have a distinctly weaker odor
than adhesives produced by known methods both in the early phase and in
the long-term phase.. Accordingly, they meet the requirements of an
integrated safety-at-work, environmental and consumer protection policy to
a high degree. By virtue of their increased percentage of renewable
biodegradable constituents, they are also environmentally compatible to an
increased extent.
The resin preparation according to the invention is distinguished by
a low viscosity at 70°C. It is below 3 Pas and preferably below 2.5 Pas
for
a mixture of 80% by 'weight rosin and 20% by weight wax (Brookfield BT,
spindle 4, 20 r.p.m.). This surprising effect may be utilised in different
ways, for example to increase the resin concentration or to lower the
processing temperature. It also has an effect on the theology of the
adhesive: the dispersion is easier to spread.
The resin preparations according to the invention may be used for
the production of resin-containing polymer dispersions or resin-containing
aqueous dispersion adhesive. Polymer dispersions known per se with
adequate shear stability at 20 to 70°C, for example aqueous dispersions
of
homo-, co- and above all block copolymers based on acrylates,
methacrylates, acrylic; acid, methacrylic acid, acrylonitrile, vinyl acetate,
vinyl chloride, ethylene, styrene, butadiene, etc. and mixtures of such
polymer dispersions, have proved to be suitable for this purpose. This list
r
CA 02336996 2001-O1-10
WO 00/02972 11 PCT/EP99104580
is intended purely as an example: the basic suitability of other polymer
dispersions may be established by simple laboratory tests. Homopolymers
and copolymers of vinyl acetate, more particularly with ethylene, and
homopolymers and copolymers of acrylates containing 1 to 22 carbon
atoms in the alcohol component, more particularly with styrene or
acrylonitrile, are preferred.
The resin prc;parations according to the invention may be
incorporated in dispersion adhesives by various methods known to the
expert as already hitherto practised with known resin preparations. In the
most simple case, the polymer dispersion - optionally containing
dispersants and defoamers and other additives and fillers - is introduced
first and the liquid resin preparation is dispersed therein in portions. Both
the dispersion preparation introduced first and the resin preparation may
have a temperature of 20 to 95°C and preferably a temperature of 50 to
85°C during the diispersion process. The optimum incorporation
temperatures are dependent on the temperature stability of the dispersion
preparation and the viscosity of the resin preparation. Dispersion is
continued until a homogeneous resin preparation is present. The expert on
dispersion adhesives is familiar with this procedure.
In a preferred embodiment, the still resin-free dispersion preparation
is introduced into a hE:atable mixing vessel and heated to a temperature of
20 to 95°C. The liquid resin preparation is then added with stirring at
a
temperature of 20 i',o 95°C and incorporated by dispersion until a
homogeneous resin preparation is obtained.
The dispersion adhesives according to the invention preferably
consist of:
a) 5 to 60% by weight of the resin preparation according to the invention
and
b) 40 to 95% by wf:ight of aqueous polymer dispersions and emulsions
known per se optionally containing additional dispersants, defoamers,
a t r
1
CA 02336996 2001-O1-10
WO 00102972 12 PCT/EP99/04580
preservatives, thickeners, anti-flow agents, additives and fillers known
per se.
Aqueous adhesive dispersions based on polyacrylates containing
the preparation according to the invention of rosin and fatty compounds are
particularly preferred. They are particularly suitable for bonding interior
floor coverings, wall coverings and ceiling coverings.
The adhesives according to the invention are distinguished by high
wet bond strength, good spreadability, minimal emission and above all by
the substantial absen<;e of odor.
Examples
I. Determination of the softening points of the waxes or wax mixtures
Components % by weightSoftening point
(C)
Palmitic/stearic acid methyl ester100 27.1 ',
(ca. 50:50) techn.
Palmitic/stearic acid methyl ester90 25.5
(ca. 50:50) techn.
Epoxidized fatty acid methyl ester10
Palmiticlstearic acid methyl ester70 22.3
(ca. 50:50) techn,
Epoxidized fatty acid methlll 30
ester
Palmiticlstearic acid methyl ester70 21.5
(ca. 50:50) techn.
Dibutyl phthalate 30
Palmiticlstearic acid methyl ester70 21.4
(ca. 50:50) techn.
Rapeseed oil methyl ester 30 '
Stearyl alcohol 100 57.0
Stearyl alcohol 70 52.5
Epoxidized fatty acid methyl ester30
Stearyl alcohol 50 50.3
Epoxidized fatty acid methyl ester50
y
f
CA 02336996 2001-O1-10
WO 00102972 13 PCT/EP99104580
Hydrogenated bovine tallow 100 50.0
Hydrogenated bovine tallow 33 43.5
Dioctyl adipate 77
Beeswax 100 62.6
Polyethylene glycol 100 51.6
Carnauba wax 100 80.5
Myristic acid 50 48.9
Epoxidized soybean oil 50
Myristic acid 100 53.3
Beeswax 75 58.9
Sunflower oil fatty acid mei:hyl 25
ester
Paraffin wax 100 59.3
Paraffin wax 50 52.8
Dioctyl adipate 50
Paraffin wax 30 47.8
Rapeseed oil methyl ester 70
Polyethylene wax 50 48.3 ',
Epoxidized fatty acid methyl ester50
Carnauba wax 70 76.7
Dioctyl adipate 30
Carnauba wax 70 77.8
Epoxidized fatty acid methyl ester30
II. Production and properties of the resin solutions
The resin solution was prepared in a heatable stirred tank. To this
end, resin and fatty acid ester were introduced in the ratio by weight shown
and stirred at a temperature of 80°C until a transparent solution was
obtained (ca. 1.5 h).
Resin solution 1: 81)% gum rosin
r
CA 02336996 2001-O1-10
WO 00/02972 14 PCT/EP99/04580
(RS 1 ) 20% myristic acid methyl ester
Resin solution 2: 80% gum rosin
(RS 2) 20% tall oil fatty acid butyl ester
Resin solution 3: 80% gum rosin
(RS 3) 20% palmiticlstearic acid methyl ester (in a ratio by
weight of ca. 50:50)
Table II. Properties of the resin solution
RS 1 RS 2 RS 3
Viscosity (mPas)2,900 3,100 1,200
Odor 3.5 4.5 3.5
Remarks:
The properties were determined as follows:
1. Viscosity measurement: Brookfield HBT, spindle 4, 20 r.p.m., 70°C
2. Odor test: Ca. 50 g of resin solution were poured into a 250 ml
screw-top glass; flask which was then closed and stored for 3 days at
23°C. At least 5 volunteers then evaluated the odor on the following
scale: 1 odorless, 2 perceptible, 3 tolerable, 4 troublesome, 5
intolerable. '
III. Use of the resin solutions for the production of adhesives
The resin solutions heated to around 80°C were added over a period
of 30 minutes with vigorous stirring at 20°C to an aqueous dispersion
with
the following composition (in % by weight):
Adhesives 1-3 Adhesive 4
Acrylate copolymer dispersion 25 25
Dispersion aids/emulsifiers 2 2
CA 02336996 2001-O1-10
r
WO 00102972 15 PCT/EP99104580
Preservative 0.1 0.1
Defoamer 0.1 0.5
Filler (CaC03) 50 49
Resin solution 17 17
Water 5.3 5.3
Epoxidized fatty acid rnethyl 0 1
ester
The acrylate copolymer dispersion is a commercially available 60%
aqueous dispersion of a copolymer of - mostly - butyl acrylate and less than
15% of acrylonitrile (a product of BASF). The adhesives were tested, the
test results being set out in Table III.
Table III. Adhesive properties
Adhesive Adhesive Adhesive Adhesive
1 2 3 4
with RS with RS with RS with RS
1 2 3 4
Viscosity [Pas] 21.9 20,7 21.5 20.9
Wet bond strength
[N/cm]
after 10 mins. airing5.0 6.25 7.5 6.5
after 15 mins, airing5.5 6.25 7.5 6.5
after 20 mins, airing3.5 6.25 8.8 7.0
Open time [mins] 15 25 25 25
Odor:
adhesive, wet 3.2 4.0 3.2 3.2
adhesive, dry 2.8 4.0 2.5 2,4
Pollution of indoor > 600 < 300 < 300 < 300
air [pglrn3]
Remarks:
The tests were carried out as follows:
1. Viscosity: ',
r
CA 02336996 2001-O1-10
WO 00/02972 . 16 PCT/EP99104580
Brookfield HBT, spindle 4, 20 r.p.m., 23°C
2. Wet bond strength:
The adhesive is applied (ca. 350 glm2) with a toothed spatula to a
chipboard coatE~d with a cement-based surfacing compound. After
different airing times, 5 cm wide strips of a carpet with a fabric
backing were placed on the bed of adhesive and rubbed in. After 5
minutes, the strips were removed vertically at a rate of 1 cm/sec.
and the removal force was determined with a spring balance.
3. Open time.
The open time is the maximum period for which an adhesive may be
left to air. The end of the open time is reached when the back of a
foam-backed strip of a textile covering is less than 30% wetted.
4. Odor wet:
See odor test, resin solution.
5. Odor dry:
A ca. 200 pm thnick film of adhesive is knife-coated onto a glass plate
(5 x 10 cm) and dried for 24 h at 23°CI50% relative humidity. The
glass plate is then transferred to a 500 ml screw-top glass flask and
stored for 3 days at 23°C. The odor is evaluated in the same way as
for the resin solutions.
6. Pollution of indoor air:
The expected pollution of indoor air is determined in a model test
chamber. To thus end, 300 glm2 adhesive is applied to a glass plate
using a toothed spatula and placed in a test chamber. After 10 days'
storage under the following conditions: 23°C, 50% rel. humidity, 0.5
air changes per hour and 0.4 m2 sample per m3 air space, a sample
of the air is analyzed for volatile organic compounds. The results
are expressed as the TVOC content (= total volatile organic
compounds) in pg/m3.
7. Iodine valae:
CA 02336996 2001-O1-10 '
WO 00/02972 17 PCT/EP99/04580
The Kaufmann iodine value is determined by DGF method C-V 11 b.
The Wijs iodinE: value is determined by DGF method C-V 11 d (ISO
3961 ).
8. Transparency:
The mixture is poured into a Petri dish and visually assessed at
room temperature in a layer thickness of 5 mm: it must be clear in
appearance wii:h no streaks or fatty globules.
9. Softening points:
Method (modified ring-and-ball): 20 ml of the wax or wax mixture
are poured into a 25 ml glass beaker (diameter 30 mm, height 48
mm) and cooled to ca. 10°C in an ice bath. A cold steel ball (weight
32.2 g, diameter 19 mm) is placed on the solid mixture which is then
slowly heated. The softening point is defined as the temperature at
which the steel ball begins to sink to the bottom.
IV. Results
The results show that the resin solution according to the invention
(RS 3) and a dispersion adhesive produced therewith for floor coverings is
at least comparable in performance with known adhesives and, in addition,
is substantially free from odor. If a liquid plasticizer, for example an
epoxidized fatty acid methyl ester, is also added, there is a distinct
improvement in wet bond strength with no adverse effect on odor or VOC
content.
A comparable improvement in wet bond strength can also be
achieved by additiorn of non-epoxidized fatty acid esters, for example
palmitic acid methyl ester. Flowever, the cohesion of the adhesive is
seriously impaired, a:> can easily be demonstrated by shear tests. To the
user of the adhesive, this means that difficult floor coverings cannot be
bonded with such a soft adhesive. The use of epoxidized fatty acid esters,
more particularly epoxy stearic acid methyl ester, surprisingly does not
CA 02336996 2001-O1-10
WO 00102972 18 PCT/EP99104580
affect the cohesion of the adhesive. Epoxidized fatty acid esters are
compatible with gum rosin and non-epoxidized fatty acid esters and,
accordingly, may also be directly added to the resin mixture in quantities of
up to 15% and preferably up to 6% instead of non-epoxidized fatty acid
esters. This simplifies production of the adhesive.
