AQUEOUS DISPERSIONS OF ROSIN-BASED POLYURETHANE RESINS
The invention relates to a rosin-based polyurethane resin, obtained from a
hydroxylated fatty polyester modified with rosin, which polyester is of bio-based
origin, and also relates to aqueous dispersions of these resins and to the uses
5 thereof in aqueous coatings.
Alkyd resins in organic solvent medium, otherwise known as solvent-based
media, are resins that have been well known for a long time by those skilled in the
art, and are generally used in decorative and industrial coatings and paint
formulations. In response to questions of ease of use, odor and toxicity, specific
l o alkyd resin emulsions have been developed and marketed for about twenty years,
with advantageous performance levels in terms of gloss, drying, appearancelcolor,
stability and odor. A conventional implementation technique solution, used for
forming alkyd resin emulsions that are stable over time, consists in using a
combination of a nonionic surfactant with an anionic surfactant as described in
15 WO 20081076 360.
Despite these improvements, certain parameters and performance qualities
remain to be improved, such as the resistance to yellowing, the resistance to
blocking, the hardness and the drying.
In the field of coatings, in particular for decorative applications, commercial
20 urethane-treated alkyd resin dispersions exist, for instance ~ o r l e e ~ o lE@ 15 0 W
supplied by Worlee, which are known for rapid development of hardness and for
affording saving in terms of initial drying in paints composed of alkyd resin
dispersions, optionally mixed with other aqueous dispersions such as latices.
However, these urethane-treated dispersions are subject to problems of
25 development of yellowing over time that are more pronounced than in the case of
alkyd resin and acrylic dispersions. Furthermore, the levels of gloss are reduced
when compared with alkyd resin dispersions or (worse) acrylic dispersions, which
is why (high-quality) gloss paint formulations nowadays contain a small proportion
of urethane-treated dispersion. In parallel, there is a need to further increase the
30 level of physical drying, in particular the initial drying (drying during the first hours
after application), and if possible, without the need for a toxic siccative agent such
as cobalt or lead derivatives.
Moreover, the environmental constraints and the challenges linked to
sustainable development increase the need for linked aqueous resins and
dispersions, which have a reduced content of VOC produced with starting
materials of renewable (or non-fossil) origin.
5 The resin of the invention allows the preparation of aqueous polyurethane
dispersions based on fatty polyesters which satisfy these needs or overcome the
drawbacks of the mentioned known dispersions.
The solution of the invention is first a solution that is friendly to man and to
his environment as a result of the absence both of organic solvents with a low
10 content of VOC (volatile organic compounds) in the aqueous dispersion and the
absence of siccative agents, also known as siccatives, on drying, but also by the
choice of.the essential starting materials for the fatty polyester serving as a basis
for the polyurethane resin, insofar as a high content of these starting materials is
of renewable and durable origin and which may lead to chemical structures that
15 are more readily biodegradable.
Said aqueous binders according to the present invention are predominantly
prepared from rosin and natural fatty substances. This advantage is notable since,
in certain cases, the proportion of renewable starting materials in the polyol fatty
polyester serving as the basis for the polyurethane resin reaches a content of
20 100% relative to the overall composition of this fatty polyester resin. The durable
nature of said resin is linked to the durable and seasonal availability of said
starting materials. These same causes also make it possible to limit the
environmental impact via a reduced carbon footprint and an improved life cycle.
These two parameters reflect the impact of the manufactured products on the
25 environment and health. The use of "renewable" or "bio-based" resources in
particular makes it possible to limit the emissions of greenhouse gases such as
carbon dioxide.
Thus, the specific resin of the invention, which makes possible these
dispersions and associated technical performance qualities, is based on a fatty
30 polyester (non-oxidizable or oxidizable such as an alkyd resin) which has been
urethane-treated (with formation of polyurethane based on this polyester).
This base fatty polyester resin, of bio-based origin and, in particular, alkyd
resin and more particularly short oil or middle oil alkyd resin < 60%, uses a high
content of starting materials of renewable origin and allows specific performance
qualities, in particular as regards the development of hardness over time after
application. Similarly, reduction of yellowing may be obtained. In particular, the
novel polyurethane resin based on this polyester may be used as a binder in
5 aqueous compositions for aqueous decorative or industrial coatings that are
capable of hardening in air with or without siccative agent, preferably without
siccative agent.
The combination of the urethane groups with said specific polyester allows
additional particular advantages such as good adhesion to the substrate, good
10 flexibility, abrasion resistance, excellent blocking resistance and good mechanical
strength in general.
Among the advantages of the present invention over the prior art, mention
may be made in particular of its aptitude toward physical drying, which may be
obtained in the same manner with or without addition of siccative agent, such as
15 cobalt derivatives. More particularly, the product of the invention has the specific
capacity for drying and hardening very rapidly within the first hours of application,
as shown by the results and graph below (novel urethane-treated polyester or
polyurethane versus ~ o r l e e ~ oEl @ 15 0 W). It should be noted, in particular, that
the product achieves more than 85% of its hardness potential after only 1 hour of
20 application, without any addition of siccative agent.
A further advantage during the drying of the dispersions of resins according
to the present invention is the faster and more intense development over time of
stable hardness, without the need for addition of a siccative such as Co (cobalt) or
the like.
25 The invention first covers a specific linear or branched polyurethane resin
based on a specific fatty polyester, of bio-based origin, more particularly based on
a bio-based alkyd resin (oxidizable polyester).
Next, the invention relates to an organic binder composition based on said
resin.
30 The invention relates more particularly to an aqueous dispersion of said
polyurethane resin.
Another subject of the invention relates to a process for preparing said resin
in the form of an aqueous dispersion.
Another subject relates to a coating composition which comprises said resin
or resin dispersion.
Finally, the invention relates to a substrate coating which results from said
resin or resin dispersion.
5 Thus, the first subject of the invention relates to a linear or branched
polyurethane resin based on fatty polyester, in particular based on alkyd resin,
obtained from at least one hydroxylated fatty polyester A), with:
- said polyester A) being the product of reaction of a) an alcohol component
with b) an acid component, which acid component b) comprises bl) at least
10 one fatty acid, said fatty acid being chosen from bl.1) at least one
oxidizable fatty monoacid andlor polyacid, comprising at least one
oxidizable unsaturation or b1.2) at least one non-oxidizable fatty monoacid
andlor polyacid or b1.3) at least one mixture of fatty acids bl.1) and b1.2)
and said component b) also comprising b2) rosin andlor rosin derivatives
15 bearing at least one carboxylic acid function, said rosin andlor derivatives
b2) representing from 30% to 85%, preferably from 35% to 75%, more
preferentially from 40% to 75% and even more preferentially from 45% to
75% by weight relative to the total weight of A)
- optionally, said polyester A) having a zero oil length (0%) or an oil length of
20 between 0 and 60%, preferably from 0 to 50% and more preferentially from
0 to 40%
- optionally, said polyester A) having a weight ratio of oxidizable fatty acids
(monoacids) bl.1) relative to the overall fatty acids bl.1) + b1.2) of 0 or
greater than 0 and ranging up to 1 or globally from 0 to 1
25 and with said polyurethane resin being the product of reaction of said polyol
polyester A) with:
B) at least one diol comprising an acid function, chosen from carboxylic,
sulfonic, phosphonic or phosphinic (preferably carboxylic, sulfonic or
phosphonic and more preferentially carboxylic), said acid function optionally
30 being partially or totally neutralized in salt form with a "weak" base (of
pk, < 14), preferably chosen from amines and phosphines and
C) at least one polyisocyanate, of functionality ranging from 2 to 3, preferably
diisocyanate, more preferentially cycloaliphatic.
In point of fact, said polyurethane resin is the product of polyaddition
reaction of an alcohol component, comprising the hydroxylated fatty polyester A)
and of the diol B) with an isocyanate component consisting of at least one
polyisocyanate C). No crosslinked structure is present in said resin that may be
5 used for the aqueous resin dispersion. A resin of linear structure is obtained for a
linear and not more than difunctional fatty polyester A), with a polyisocyanate C)
chosen from diisocyanates.
The NCOIOH ratio is less than or equal to 1. When this ratio is less than 1,
said polyurethane resin bears reactive hydroxyl residual functions that may serve
10 for a crosslinking reaction during the separate step, of application (final use) for
crosslinkable coatings.
The polyisocyanate C) may be chosen from all aliphatic, cycloaliphatic or
aromatic polyisocyanates that are suitable for preparing polyurethanes by reaction
with a polyol. They may be diisocyanates or triisocyanates or derivatives of these
15 isocyanates such as diisocyanate oligomers or precondensates or prepolymers
bearing isocyanate functions with a functionality ranging from 2 to 3. These
polyisocyanates may optionally be in a form blocked with a blocking agent which is
labile under the reaction conditions.
As examples of suitable diisocyanates, mention may be made, without
20 limitation, of the following: toluene 2,4- and 2,6-diisocyanate (TDI), isophorone
diisocyanate (IPDI), hexamethylene diisocyanate (HDI), trimethyl hexamethylene
diisocyanate (TMDI), 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-dicyclohexylmethane
diisocyanate (H12MDI), 3,3'-dimethyl-4,4'-biphenyl diisocyanate, 1,4-
benzene diisocyanate, 1,5-naphthalene diisocyanate (NDI), cyclohexane 1,4-
25 diisocyanate, dodecane diisocyanate, m-tetramethylenexylylene diisocyanate, 4,6-
xylylene diisocyanate.
As examples of suitable triisocyanates, mention may be made of the
following: toluene triisocyanate, trimer TDI (such as ~esmodur@R from Bayer),
HDI trimer (such as ~esmodur@N from Bayer).
30 Preferably, said polyisocyanate is a diisocyanate and in particular
cycloaliphatic, such as IPDI, cyclohexane 1,4-diisocyanate or 4,4'-dicyclohexylmethane
diisocyanate (H12MDI).
The diol B) is a diol bearing an acid function which may be in partially or
totally neutralized (salified) form. The preferred acid function is chosen from
carboxylic, sulfonic and phosphonic and more particularly carboxylic or sulfonic
acid. As suitable preferred examples, mention may be made of:
5 dimethylolpropionic acid or the equivalent by replacing the carboxylic acid with
sulfonic or phosphonic acid.
As regards the polyol fatty polyester resin A) which is the base of this
polyurethane resin, preferably, this polyester has an acid number of less than 10,
preferably less than 6, and a hydroxyl number (10~) of at least 25, preferably from
10 50 to 150, and it has a calculated number-average molecular weight Mn ranging
from 250 to 10 000 and preferably from 250 to 6000. The calculated Mn, in the
absence of another valid indication for all of the invention, corresponds to the Mn
calculated from the OH and acid numbers and the mean functionality. The acid
numbers are measured according to the titration method IS02114 and the
15 hydroxyl numbers are calculated as a function of the amounts of material
introduced (OHICOOH mole ratio).
Said acid component b) and said polyester resin A) may comprise, in
addition to said fatty acid bl), in addition to said rosin andlor in addition to said
rosin derivatives b2), at least one acid compound b3) bearing at least one
20 carboxylic acid function, with, optionally in addition, a hydroxyl function and an
overall functionality (carboxyl +. optionally OH) of from 2 to 3, with b3) being
chosen from: b3.1) saturated polyacids andlor b3.2) ethylenically unsaturated
polyacids or b3.3) hydroxy acids.
Said acid compound bl) may be, according to a more particular case, a
25 non-oxidizable fatty polyacid b1.2) and, preferably, it comprises at least one CS6
fatty acid dimer andlor at least one C54 fatty acid trimer.
The term "fatty acid" defined according to the invention means a C12 to C54
carboxylic acid.
The term "oil length" as used in the present invention means the weight %
30 relative to the total weight of the fatty polyester resin, of the weight of "fatty
monoacids" or of standoils or standoil derivatives (standoil is a product resulting
from the reaction at high temperature, 250-30O0C, of a mixture of oil and of fatty
acid), this weight % being expressed as a weight equivalent of triglyceride
derivatives (oils) which correspond to the fatty acids b l . l ) , said fatty acids being
"oxidizable". Any calculation and mention of this characteristic in the present
invention is based on this definition. The term "oxidizable fatty acids" for bl.1)
means, according to the present invention, the fatty acids or derivatives (oils or
5 standoils) with an iodine number of greater than or equal to 80 mg of iodine per g
of product. Said fatty monoacids or triglycerides (oils) may be mixtures of natural
origin and may comprise up to 30% by weight of oxidizable saturated or
unsaturated fatty acids b1.2).
The hydroxylated fatty polyester resin A) according to the present invention
l o is in particular characterized by the presence in the acid component b) of the
major component b2) bearing at least one carboxylic function and which is chosen
from rosin and derivatives thereof, including maleic-treated or acrylic derivatives of
rosin which may bear from 3 to 4 carboxylic functions.
According to a preferred embodiment, the polyester A) of the invention
15 comprises less than 5%, preferably less than 3% by weight and more preferentially
no (0%) aromatic compound such as of phthalic type (phthalic, isophthalic,
trimellitic or terephthalic acid or anhydride), besides the rosin derivatives optionally
used. The term "rosin derivatives" means natural derivatives such as
dehydroabietic acid.
20 The oxidizable saturated or unsaturated fatty acids b1.2) used do not bear
any reactive ethylenic unsaturation (i.e. if there is an unsaturation, it is not
oxidizable) and may also be derived from the hydrogenation of unsaturated fatty
acids b l ) bearing at least one reactive unsaturation (oxidizable and
hydrogenated). More particularly, said acid component b) may comprise b1.3) a
25 mixture of at least two among said acid compounds bl.1) and b1.2).
The polyester resin A) according to another preferred case is based on an
acid component comprising, in addition to said fatty acid bl), in addition to b2) said
rosin andlor said rosin derivatives, at least one acid compound b3) bearing at least
one carboxyiic acid function and having an overall functionality of 2 to 3, the
30 overall functionality including the acid function and an optional other possible
function, such as hydroxyl, said compound b3) being chosen from: b3.1) saturated
polyacids or b3.2) ethylenically unsaturated polyacids or b3.3) hydroxy acids.
As suitable saturated polyacid b3.1), the choice may be made from the acid
and/or anhydride corresponding to: succinic acid, adipic acid, sebacic acid,
dodecanedioic acid, citric acid (functionality 3), the C36 fatty acid dimer (of
functionality 2 to 2.2) or the Cs4 fatty acid trimer (of functionality 2.5 to 3). As
5 suitable unsaturated polyacid b3.2), the choice may be made from the existing
acid andlor anhydride corresponding to: itaconic acid of functionality 2, maleic or
fumaric acid of functionality 2 or tetrahydrophthalic acid (THP) of functionality 2.
Among the preferred polyacids, mention may be made of polyacids comprising at
least one C36 fatty acid dimer andlor C54 fatty acid trimer. As preferred hydroxy
10 acids b3.3), mention may be made of glycolic acid or lactic acid.
A combination of several polyacids and monoacids is often used in order to
optimize the physicochemical properties of the polyurethane resin which results
from polyester A) in particular the alkyd resin, more particularly to obtain the
desired compromise of hardnesslsuppleness or flexibility. The incorporation into A)
15 according to the invention, in particular into the alkyd resins, of aromatic acid
derivatives such as phthalic (diacidlanhydride) or benzoic (monoacid) is possible,
but, preferably, with a proportion of less than 5% by weight, and more
preferentially with less than 3% by weight. Even more preferentially, there is no
aromatic derivative (0% aromatics) outside of any natural rosin derivatives.
20 The presence of a monoacid component such as abietic or primaric acids,
in particular of rosin andlor derivatives thereof, and more particulariy in such a
high proportion, constitutes the essential element of the structure of the polyester,
in particular alkyd resin A) as defined according to the invention, for allowing the
particular properties observed. The proportion of rosin in A) is high and ranges
25 from 30% to 85%, preferably from 35% to 75%, more preferentially from 40% to
75% and even more preferentially from 45% to 75%. The fatty acids used, taking
into account their natural origin, are mixtures as defined according to b1.3)
comprising oxidizable saturated or unsaturated fatty acids bl.1) and unsaturated
fatty acids b1.2) bearing non-conjugated unsaturations and conjugated
30 unsaturations. These fatty acids, and also the fatty acid dimers andlor trimers
synthesized from these same natural fatty acids, provide the suppleness and
flexibility necessary for the binder and the coating obtained which results
therefrom.
According to a preferred mode of the invention, the polyurethane resin of
the invention is based on a fatty polyester A) in which said oxidizable fatty acid
b l .I) is selected from fatty monoacids of plant or animal origin, preferably of CI6 to
CZ4, with a mean iodine number ranging from 100 to 200 mg I2/g.
5 As regards the alcohol component a) of said polyol fatty polyester resin A),
it may preferably comprise at least one polyol of functionality ranging from 2 to 10
and more preferentially from 2 to 6.
The polyols a) that are suitable according to the invention may be selected
from: ethylene glycol, polyethylene glycol, preferably with a number-average
10 molecular mass Mn (calculated from the OH number) ranging from 250 to 3000,
propylene glycol (1,2-propanediol), 1,3-propanediol, dipropylene glycol, triethylene
glycol, glycerol, diglycerol, trimethylolpropane or trimethylolethane, pentaerythritol,
dipentaerythritol, sorbitol, mannitol, methyl glucoside, polyglycerol, in particular
glycerol oligomers, such as polyglycerol-3 (glycerol trimer) and decaglycerol and
15 preferably glycerol oligomers and mixtures thereof, such as polyglycerol-3, which
polyglycerol-3 is a mixture of glycerol oligomers (glycerol oligomerized with the
presence of oligomers containing 30% to 55% by weight of glycerol trimer
constituting the predominant oligomer) this product being sold by Solvay. The
preferred polyol is glycerol and/or pentaerythritol.
20 More particularly, said polyol a) may be selected from: ethylene glycol,
polyethylene glycol, preferabiy of Mn from 250 to 3000, propylene glycol, 1,3-
propanediol, dipropylene glycol, triethylene glycol, glycerol, diglycerol,
trimethylolpropane (or -ethane), pentaerythritol, dipentaerythritol, sorbitol,
mannitol, methyl glucoside and polyglycerol, in particular glycerol.
25 According to a preferred mode of the invention, said polyurethane resin and
associated aqueous dispersion is based on a fatty polyester resin A), in which said
polyacid b1.2) comprises at least one C36 fatty acid dimer andlor CS4 fatty acid
trimer and in that said polyol a) comprises glycerol or at least one glycerol
oligomer andlor pentaerythritol and/or dipentaerythritol and preferably glycerol
30 and/or pentaerythritol.
In the polyurethane resin according to the present invention, said acid
function of said diol B) may be in a form neutralized (salified) with a neutralizing
agent which is a weak base, preferably selected from tertiary amines, in particular
trialkylamines or phosphines and more preferentially it is neutralized (salified) with
tertiary amin'es. The neutralizing agent is a weak base, which means a basicity
less than that of sodium hydroxide or of potassium hydroxide (pK, < 14).
According to a particular case, said polyurethane resin of the invention
5 bears hydroxyl reactive groups, preferably with an OH number of at least 20, more
preferentially of at least 40. They are in fact residual OH groups remaining after
the reaction between the alcohol component comprising the polyol fatty polyester
and the diol B) and the polyisocyanate C). In general, for the polyurethane resin,
an excess of at least 5% of OH functions relative to the isocyanate functions NCO
10 is used. In the particular case in which polyurethane resins with an OH number as
indicated below are targeted, in this case, the excess of OH functions relative to
the isocyanate functions is adjusted as a function of this number. The presence of
these residual OH functions allows additional modification of the resin of the
invention, but above all its crosslinking at a subsequent stage during its use in a
15 final application of coating. The crosslinking may be performed with a suitable
crosslinking agent (reactive relative to the hydroxyl functions and multifunctional),
for instance melamine, and blocked or unblocked polyisocyanates.
The second subject of the invention relates to an organic binder
composition which comprises at least one resin as defined according to the
20 invention described above. This binder composition may comprise, in addition to
the resin of the invention, at least a second resin different from the first, this
second resin being selected from fatty acid-based polyester resins, preferably from
modified alkyd resins. Among the modified alkyd resins that are suitable for this
composition, mention may be made of alkyd resins modified with an acrylic
25 structure, alkyd resins modified with styrene, modified with amides or modified with
silicone.
Another subject of the invention relates to an aqueous dispersion of resin
which comprises at least one polyurethane resin or at least one binder
composition of the invention, preferably with said acid function of said diol B) being
30 partially or totally neutralized with a weak base, preferably chosen from amines, in
particular tertiary amines or phosphine, preferably tertiary amines and in particular
trialkylamines such as triethylamine (TEA).
Preferably, said dispersion has a solids content ranging from 20% to 60%
and preferably from 30% to 50% and a mean particle size ranging from 30 to
200 nm.
More particularly, it may be free of any organic solvent with a corresponding
5 VOC content of less than 5000 ppm, preferably less than 1000 ppm and more
preferentially less than 500 ppm.
This aqueous resin dispersion according to the invention may comprise a
mixture of dispersions, with at least a first aqueous resin dispersion according to
the invention and with at least a second resin dispersion different from the first,
10 this second resin dispersion being selected from optionally modified alkyd resin
dispersions, acrylic dispersions (or emulsions) (including styrene-acrylics) or
dispersions of other polymers and in particular polyurethane or saturated or
unsaturated polyester dispersions. In this case, the weight content of said first
dispersion may range from 50% to 99.5% relative to said mixture.
15 A more particular case of an aqueous dispersion according to the invention
is that in which said dispersion comprises a polyurethane resin bearing OH groups
with an OH number of at least 20 and more preferentially of at least 40. Such a
dispersion may be used in particular for aqueous compositions of crosslinkable
coatings in the presence of a multi-functional crosslinking agent bearing functions
20 that are reactive with OH groups. A suitable example of such a crosslinking agent
is melamine, blocked or unblocked polyisocyanates.
The invention next relates to a process for preparing said polyurethane
resin and more particularly in the form of an aqueous dispersion. By definition, this
also relates to a process for preparing said aqueous dispersion.
25 This process for preparing a resin of the invention, in the form of an
aqueous dispersion, comprises at least the following successive steps:
i) preparing a (fatty) polyol polyester A) as defined above, by bulk
polycondensation reaction in the melt of said alcohol a) and acid b)
components, until an acid number of less than 10 is obtained,
30 ii) dissolution and dilution of said polyester in a volatile solvent (with a boiling
point of less than 150°C, preferably less than 10O0C),
iii) polyaddition reaction in solvent medium of said polyester A) as obtained in
step ii) by addition of said diol B) and of said polyisocyanate, preferably
diisocyanate C), with partial or total neutralization of said acid function of B)
with a weak base chosen from amines or phosphines, preferably amines, in
particular tertiary amines, said neutralization possibly taking place prior to
or subsequent to said polyaddition,
5 iv) at the end of the reaction of step iii), dispersion in water with stirring of the
polyurethane solution as obtained in step iii), before
v) removal of said organic solvent by evaporation or by steam stripping or by
an inert gas-stripping.
The use of the polyurethane resins and of the aqueous dispersions based
10 on these resins of the invention are suitable in particular for applications in
aqueous coatings.
Thus, the invention relates more particularly to an aqueous coating
composition which comprises as binder at least one resin or at least one binder
composition or at least one aqueous dispersion as defined above according to the
15 invention. These compositions are distinguished from the prior art in terms of
applicative performance qualities, more particularly as regards the faster
development of hardness and the rapid physical drying and with a development of
yellowing that is reduced and controlled over time. The coatings resulting
therefrom have additional performance qualities, including: abrasion resistance,
20 good flexibility, blocking resistance, adhesion and mechanical strength. Given the
particular adhesion of the polyurethane reslns to a metal substrate and the barrier
effect characterized by the high hydrophobicitylhardness of the rosin-based
binder, this type of binder gives the final coating particularly efficient anticorrosive
properties. This is an application targeted in particular for the aqueous coatings
25 based on polyurethane resin of the present invention. The other advantage due to
the chemical composition of the resin is that this binder is highly bio-based.
According to a more particular case, said coating composition of the
invention is crosslinkable and comprises at least one aqueous dispersion of
polyurethane resin according to the present invention comprising hydroxyl groups
30 (residual from the reaction with said polyisocyanate), preferably with an OH
number of at least 20, more preferentially of at least 40 and said dispersion also
comprises at least one crosslinking agent that can react with said hydroxyl
functions, said crosslinking agent preferably being selected from: melamine,
blocked or unblocked polyisocyanate, epoxy and silane.
The coating composition of the invention is more particularly used for
aqueous coatings such as adhesives, paints, surface coatings, primers and
5 varnishes. According to a particular preferred embodiment, these compositions
have a reduced content of siccatives and more preferentially they are free of
siccatives such as heavy metal salts, for instance cobalt or tin salts and more
particularly they do not contain any siccative.
Finally, the invention relates to a substrate coating as obtained from at least
10 one resin or a binder composition or an aqueous dispersion as defined above
according to the invention.
The invention is illustrated without limitation of coverage by the examples
presented below.
EXPERIMENTAL SECTION
1) Preparation of a polyol fattv polvester resin A) and characteristics
Example 1
Said polyester A) is formed by "one-pot" condensation at 230-250°C of a
5 mixture composed of glycerol, fatty acid dimer (pripolB 1017 sold by Croda) and
rosin in the following mass proportions (see table 1):
Table 1: composition of the reagents
Components
( dimer) with IA : 195-210 1 I
I
pripolB 1017 (fatty acid
I
I Oxidizable unsaturation: 0 1 1
Supplier
Croda
Parts by weight
540.8
I I
10 The condensation is stopped so as to obtain a final viscosity of 70 Pa.s
(measured at 110°C using a CAP 1000 viscometer) with an acid number of less
than 10 mg KOHIg (between 6 and 8).
Calculated characteristics of resin A):
- loH: 90 mg KOHIg (calculated by the excess OH)
15 - IA: 6 mg KOHIg (method IS0 21 14)
- % rosin: 50%
- oil length: 40%
- oxidizable unsaturation: 0 mg lz/g
- Mn: calculated from the IA + lo^ data and functionality: 1140 glmol (for
20 IA = 6 mg KOHIg, I , OH = 90 mg KOHIg and functionality = 1.58).
Glycerol
I I
2) Preparation of an aclueous dispersion of polyurethane resin (and indirectly
of the polyurethane resin)
Polyester A) as described in example 1 above is diluted in acetone so as to
25 be polyurethane-modified therein in the presence of isophorone diisocyanate
(IPDI), dimethylolpropionic acid (DMPA) and triethylamine (TEA), and the product
is then finally dispersed in water after virtually complete reaction of the isocyanate
Rosin (gum rosin)
Solvay 197.9
Ter-Hell & Co GMBH 759.4
functions. The proportions are indicated in table 2 and the procedure is detailed
below.
Table 2: Composition of reagents for the preparation of the polyurethane resin
5 according to the invention
Detailed procedure:
Acetone (portion I: i.e. 197.5 g) and then DMPA and TEA are introduced
with mechanical stirring onto the molten polyester A) described in example 1, at
10 between 50 and 60°C. The medium is then refluxed for 45 minutes at about 54"C,
and IPDl is then introduced rapidly in a single portion. The urethanization reaction
(formation of polyurethane) is monitored by FTlR (Fourier Transform InfraRed)
until a conversion of the isocyanate functions (NCO) of about 94% is obtained.
Acetone (portion 2: 93 g) is then added to the medium, and water is then
15 introduced over 10 minutes at between 35°C and 40°C. The acetone (and part of
the water) is then evaporated off at atmospheric pressure at 55-60°C and while
sparging with nitrogen until a final solids content of about 40% by weight is
obtained. The polyurethane resin dispersion (PUD) is then filtered off on a
25 micron gauze.
20 The characteristics of the final dispersion are given in table 3 below.
Table 3: Characteristics of the final dispersion
3) Results and performance clualities on coatinas
Development of hardness over time
5 The hardness evaluation is performed on films obtained by application to a
glass plate of a coat of aqueous resin dispersion of example 2 with a wet thickness
of 100 pm.
The hardness test is according to method IS0 1522. It is a pendulum
hardness (Persoz) performed at 23°C and at 50% relative humidity. The varnishes
10 are applied to a wet thickness of 100 pm and then dried on a perfectly horizontal
surface at 23°C and at a relative humidity of 50% for 24 hours before the first
measurement.
The results obtained are presented in the form of graphs compared in
figures 1 and 2, in which the performance qualities of the dispersion according to
15 the invention of example 2 are compared with those of a commercial dispersion
orl lee Sol@ E 150 W sold by Worlee representing the prior art (siccative-treated
and non-siccative-treated).
Characteristic
I OH (mg KOHIS)
PH
Malvern particle size (nm)
Brookfield viscosity DVII+ at
25"CIlOO rpm (mPa.s)
Figure 1 shows the strictly comparative drying, obtained under the same
test conditions, without addition of siccative (such as cobalt derivatives). The
20 essential characteristic of the product of the invention, which emerges from this
comparison, is its capacity to physically dry and to harden very rapidly from within
the first hours of application. According to the graph of figure 1, the resin
dispersion according to example 2 of the invention compared with or lee Sol@
Value
26
8-9
70
150
E 150 W dries and hardens much more rapidly and above all more intensely than
25 the reference product representing the prior art. The product according to the
invention achieves more than 85% of its hardness potential after only 1 hour of
application, and without addition of siccative.
Figure 2 shows, spectacularly, that the resin dispersion according to the
invention of example 2, even when not siccative-treated, once again remains
5 superior to the reference commercial resin dispersion siccative-treated with cobalt
( ~ d d i t o l 6@20~6 s~ol~d b y Cytec, added to 1.5% by weight on dry resin).
The other advantages are: the lower level of yellowing with the same
performance with or without addition of siccative.

CLAIMS
1. A linear or branched polyurethane resin based on fatty polyester, in
particular based on alkyd resin, characterized in that it is obtained from at least
5 one hydroxylated fatty polyester A), with:
- said polyester A) being the product of reaction of a) an alcohol component
with b) an acid component, which acid component b) comprises bl) at least
one fatty acid, said, fatty acid being chosen from bl.1) at least one
oxidizable fatty monoacid andlor polyacid, comprising at least one
10 oxidizable unsaturation or b1.2) at least one non-oxidizable fatty monoacid
andlor polyacid or b1.3) at least one mixture of fatty acids bl.1) and b1.2)
and said component b) also comprising b2) rosin andlor rosin derivatives
bearing at least one carboxylic acid function, said rosin andlor derivatives
b2) representing from 30% to 85%, preferably from 35% to 75%, more
15 preferentially from 40% to 75% and even more preferentially from 45% to
75% by weight relative to the total weight of A)
- optionally, said polyester A) having a zero oil length (0%) or an oil length of
between 0 and 60%, preferably from 0 to 50% and more preferentially from
0 to 40%
20 - optionally, said polyester A) having a weight ratio of oxidizable fatty acids
(monoacids) bl.1) relative to the overall fatty acids bl.1) + b1.2) of 0 or
greater than 0 and ranging up to 1
and with said resin being the product of reaction of said polyol polyester A) with:
B) at least one diol comprising an acid function, chosen from carboxylic,
25 sulfonic, phosphonic or phosphinic (preferably carboxylic), sulfonic or
phosphonic and more preferentially carboxylic, said acid function optionally
being partially or totally neutralized in salt form with a weak base, preferably
chosen from amines and phosphines and
C) at least one polyisocyanate, of functionality ranging from 2 to 3, preferably
30 diisocyanate, more preferentially cycloaliphatic.
2. The resin as claimed in claim 1, characterized in that said acid component
b) comprises, in addition to said fatty acid bl), in addition to said rosin andlor in
addition to said rosin derivatives b2), at least one acid compound with b3) having
at least one carboxylic acid function, optionally with, in addition, a hydroxyl
function and an overall functionality of 2 to 3, with b3) being chosen from b3.1)
saturated polyacids andlor b3.2) ethylenically unsaturated polyacids or b3.3)
5 hydroxy acids.
3. The resin as claimed in claim 1 or 2, characterized in that said acid
compound bl) is a non-oxidizable fatty polyacid b1.2) and it preferably comprises
at least one C36 fatty acid dimer andlor at least one C54 fatty acid trimer.
4. The resin as claimed in one of claims 1 to 3, characterized in that said
10 alcohol component a) comprises at least one polyol of functionality ranging from 2
to 10 and preferably from 2 to 6.
5. The resin as claimed in claim 4, characterized in that said polyol is selected
from: ethylene glycol, polyethylene glycol preferably of Mn from 250 to 3000,
propylene glycol, 1,3-propanediol, dipropylene glycol, triethylene glycol, glycerol,
15 diglycerol, trimethylolpropane (or -ethane), pentaerythritol, dipentaerythritol,
sorbitol, mannitol, methyl glucoside, polyglycerol, in particular glycerol andlor
pentaerythritol.
6. The resin as claimed in one of claims I to 5, characterized in that said
polyester A) has an acid number of less than 10, an OH number of greater than
20 25, preferably ranging from 50 to 150, and a calculated number-average molecular
weight Mn ranging from 250 to 10 000 and preferably from 250 to 6000 (glmoi).
7. The resin as claimed in one of claims 1 to 6, characterized in that said
oxidizable fatty acid bl.1) is selected from fatty monoacids of plant or animal
origin, preferably of C16 to C24, with a mean iodine number ranging from 100 to
25 200 mg 12/g.
8. The resin as claimed in one of claims 1 to 7, characterized in that said
polyacid b1.2) comprises at least one C36 fatty acid dimer andlor a C54 fatty acid
trimer and in that said polyol a) comprises glycerol or at least one glycerol
oligomer andlor pentaerythritol andlor dipentaerythritol and preferably glycerol
30 andlor pentaerythritol.
9. The resin as defined according to one of claims 1 to 8, characterized in that
said acid function of said diol B) is in a form neutralized (salified) with a weak base
selected from tertiary amines, in particular trialkylamines or phosphines and more
preferentially tertiary amines.
10. The resin as claimed in one of claims 1 to 9, characterized in that it
comprises hydroxyl reactive groups, preferably with an OH number of said
5 polyurethane resin of at least 10 and more preferentially of at least 20.
11. An organic binder composition, characterized in that it comprises at least
one resin as defined according to one of claims I to 10.
12. The composition as claimed in claim 11, characterized in that, in addition to
the resin as defined according to one of claims 1 to 10, it comprises at least a
10 second resin different from the first, this second resin being selected from resins of
polyesters based on fatty acids, preferably from modified alkyd resins.
13. An aqueous resin dispersion, characterized in that it comprises at least one
resin as defined according to one of claims 1 to 10 or at least one binder
composition as defined according to claim 11 or 12, preferably with said acid
15 function of said diol B) being partially or totally neutralized with a weak base,
preferably chosen from amines, in particular tertiary amines or phosphine,
preferably tertiary amines and in particular trialkylamines.
14. The dispersion as claimed in claim 13, characterized in that it has a solids
content ranging from 20% to 60% and preferably from 30% to 50% and a mean
20 particle size ranging from 30 to 200 nm.
15. The dispersion as claimed in claim 13 or 14, characterized in that it is free
of any organic solvent with a corresponding VOC content of less than 5000 ppm,
preferably less than 1000 ppm and more preferentially less than 500 ppm.
16. An aqueous resin dispersion, characterized in that it comprises a mixture of
25 at least a first aqueous resin dispersion as defined according to one of claims 13
to 15 with at least a second resin dispersion different from the first, this second
resin dispersion being selected from optionally modified alkyd resin dispersions,
acrylic dispersions (or emulsions) (including styrene-acrylic) or dispersions of other
polymers and in particular polyurethane or saturated or unsaturated polyester
30 dispersions.
17. The dispersion as claimed in claim 16, characterized in that the weight
content of said first dispersion is from 50% to 99.5% relative to said mixture.
18. The aqueous dispersion as claimed in one of claims 13 to 17, characterized
in that it comprises a resin as defined according to claim 10.
19. A process for preparing a resin as defined according to one of claims 1 to
10 in the form of an aqueous dispersion, characterized in that it comprises the
5 following successive steps:
i) preparing a polyol polyester A) as defined in one of claims 1 to 10, by bulk
polycondensation reaction in the melt of said alcohol a) and acid b)
components, until an acid number of less than 10 is obtained,
ii) dissolution and dilution of said polyester in a volatile solvent with a boiling
10 point of less than 15O0C, preferably less than 10O0C,
iii) polyaddition reaction in solvent medium of said polyester A) as obtained in
step ii) by addition of said diol B) and of said polyisocyanate, preferably
diisocyanate C), with partial or total neutralization of said acid function of 6)
with a weak base chosen from amines or phosphines, preferably amines, in
15 particular tertiary amines, said neutralization possibly taking place prior to
or subsequent to said polyaddition,
iv) at the end of the reaction of step iii), dispersion in water with stirring of the
polyurethane solution as obtained in step iii), before
v) removal of said organic solvent by evaporation or by steam-stripping or by
20 an inert gas stripping.
20. An aqueous coating composition, characterized in that it comprises as
binder at least one resin as defined according to one of claims 1 to 10 or at least
one binder composition as defined according to claim 11 or 12 or at least one
aqueous dispersion as defined according to one of claims 13 to 18.
25 21. The coating composition as claimed in claim 20, characterized in that it
comprises at least one dispersion as defined according to claim 18 and at least
one crosslinking agent that can react with hydroxyl functions, preferably selected
from: melamine, blocked or unblocked polyisocyanate, epoxy and silane.
22. The coating composition as claimed in claim 20 or 21, characterized in that
30 said coating is selected from aqueous coatings: adhesives, paints, surface
coatings, primers and varnishes.
23. The coating composition as claimed in one of claims 20 to 22, characterized
in that it is an anticorrosion coating.
24. A substrate coating, characterized in that it is obtained from at least bne.
resin as defined according to one of claims 1 to 10 or from a binder composition as
defined according to claim 11 or 12 or at least one aqueous dispersion as defined
according to one of claims 13 to 18.