U.S. patent application number 13/487084 was filed with the patent office on 2012-09-20 for crosslinking method.
This patent application is currently assigned to MONASH UNIVERSITY. Invention is credited to William Roy Jackson, Jim Patel, Andrea Jane Robinson, Algirdas Kazimieras Serelis, Christopher Henry SUCH.
Application Number | 20120238693 13/487084 |
Document ID | / |
Family ID | 37604033 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120238693 |
Kind Code |
A1 |
SUCH; Christopher Henry ; et
al. |
September 20, 2012 |
CROSSLINKING METHOD
Abstract
The invention provides a method of preparing a crosslinked
polymer, which method comprises polymerising branched
polyunsaturated monomers by a metathesis polymerisation reaction,
wherein the branched polyunsaturated monomers contain acyclic
ethylenically unsaturated groups that are capable of undergoing
polymerization by a metathesis reaction such that the metathesis
polymerisation produces a crosslinked polymer and substantially no
non-volatile ethylenically unsaturated by-products.
Inventors: |
SUCH; Christopher Henry;
(Mount Eliza, AU) ; Patel; Jim; (Parkdale, AU)
; Jackson; William Roy; (Camberwell, AU) ;
Robinson; Andrea Jane; (St Kilda, AU) ; Serelis;
Algirdas Kazimieras; (Mount Waverley, AU) |
Assignee: |
MONASH UNIVERSITY
Clayton
AU
DELUXGROUP (AUSTRALIA) PTY. LTD
Clayton
AU
|
Family ID: |
37604033 |
Appl. No.: |
13/487084 |
Filed: |
June 1, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11988180 |
Mar 5, 2009 |
8211989 |
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PCT/AU2006/000930 |
Jun 30, 2006 |
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13487084 |
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60695439 |
Jul 1, 2005 |
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Current U.S.
Class: |
524/570 ;
526/171; 554/163 |
Current CPC
Class: |
C11C 3/00 20130101; C08G
61/00 20130101; C07C 67/333 20130101; C07C 67/333 20130101; C09D
165/00 20130101; C07C 69/533 20130101 |
Class at
Publication: |
524/570 ;
526/171; 554/163 |
International
Class: |
C08F 110/00 20060101
C08F110/00; C11C 3/00 20060101 C11C003/00; C09D 123/00 20060101
C09D123/00 |
Claims
1-21. (canceled)
22. A coating or adhesive product comprising: (1) branched
polyunsaturated monomers that: (a) comprise at least a general
structural unit (I): BR.sup.1R.sup.2R.sup.3 (1) where B represents
an atom or core, and where each moiety R.sup.1, R.sup.2 and
R.sup.3, which may be the same or different, contains at least one
acyclic ethylenically unsaturated group which (i) is located within
6 atoms from the end of the moiety, and (ii) is capable of
undergoing polymerization by a metathesis reaction contain terminal
or near terminal acyclic ethylenically unsaturated groups that are
capable of undergoing polymerisation by a metathesis reaction to
form a crosslinked polymer to afford a crosslinked polymer and
substantially no non-volatile ethylenically unsaturated
by-products, and (b) are, or are derived from, a natural oil, and
(2) an olefin metathesis catalyst.
23. The coating or adhesive product according to claim 22 in the
form of a two-part curable system, wherein the branched
polyunsaturated monomers are provided in the first part and the
olefin metathesis catalyst is provided in the second part.
24. The coating or adhesive product according to claim 23, wherein
the first part further comprises acyclic diene monomers.
25. The coating or adhesive product according to claim 23, wherein
the second part further comprises a polymer formed through acyclic
diene metathesis polymerisation.
26. The coating or adhesive product according to claim 22, wherein
the olefin metathesis catalyst is selected from Grubbs catalyst
first and second generation.
27. A method of preparing near terminal ethylenically unsaturated
carbonyl compounds, which method comprises subjecting a carbonyl
compound comprising an acyclic ethylenically unsaturated group to a
cross-metathesis reaction with substantially pure 2-butene.
28. The method according to claim 27, wherein the carbonyl compound
comprises one or more carbonyl functional groups selected from an
ester, an amide, a ketone an aldehyde, a carboxylic acid and
combinations thereof.
29. The method according to claim 27, wherein the cross-metathesis
reaction provides for a productive turn over number of greater than
about 10,000.
30. The method according to claim 27, wherein the carbonyl compound
is a natural oil, a fatty acid derived from a natural oil, or a
fatty acid ester derived from a natural oil.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a method for preparing
crosslinked polymers, and to crosslinked polymers prepared by the
method. The invention also relates to precursor compositions that
can be crosslinked in accordance with the method, and to a method
for preparing compounds that can be used to prepare the crosslinked
polymers. The method for preparing the crosslinked polymers is
particularly suited for use in polymer-based coating and adhesive
applications, and accordingly it will be convenient to hereinafter
describe the invention with reference to these applications.
However, it is to be understood that the method may also be
employed in other applications.
BACKGROUND OF THE INVENTION
[0002] Crosslinked polymers can generally be characterised as a
network of polymer chains in which at least some of the chains are
connected through a bridging group. The nature of the bridging can
vary significantly, as can the manner in which the bridging group
forms its connection with the polymer chains. The number of
bridging groups present, that is the degree of crosslinking, in a
crosslinked polymer can also vary significantly, with the effective
molecular weight, viscosity and solubility of the polymer changing
as the degree of crosslinking in the polymer increases. Polymers
with any significant degree of crosslinking are generally
substantially insoluble in solvents.
[0003] Crosslinked polymers typically exhibit superior physical and
mechanical properties compared to their non-crosslinked
counterparts. The properties of polymer-based coatings and
adhesives (i.e. paints, adhesives, fillers, primers and sealants
etc) can therefore also generally be improved by providing such
products with a crosslinked polymeric structure. However, due to
their crosslinked polymer structure, crosslinked polymers are
generally not capable of being applied to a substrate in a manner
that is required for the application of most coatings and
adhesives. In particular, crosslinked polymers cannot generally be
moulded into a desired shape or applied as a layer onto the surface
of a substrate.
[0004] To provide polymer-based coatings and adhesives with a
crosslinked structure and an ability to be readily applied to a
substrate, the products are often formulated such that crosslinking
occurs after the product has been applied to the substrate. One of
the more common formulating techniques used to achieve such
post-application crosslinking is to provide the product with at
least one polymer which contains reactive functional groups. The
reactive functional groups afford sites that can react and promote
crosslinking post-application of the product.
[0005] One approach to providing such products with these reactive
functional groups has been to formulate them with unsaturated
natural oils (eg. glyceride oils), or alkyd resins formed
therefrom. Compositions formulated with these materials make up a
large percentage of coatings used globally and are commonly
referred to as air-dry enamels or oil based paints. Drying or
curing of such paints essentially results from the reaction of
atmospheric oxygen with the ethylenically unsaturated groups
derived from the oils, which in turn promotes crosslinking of the
composition in a process known as autoxidation.
[0006] However, despite being effective at forming crosslinked
polymer structures, the autoxidation process is particularly slow.
Sufficient crosslinking necessary to apply a second coat of paint
without disturbing the first can only be achieved after the film
has been allowed to dry over night. Even then, a range of
environmental factors such as temperature and humidity can retard
the rate of drying.
[0007] The process of autoxidation can also continue for a long
period of time (i.e. post drying of the paint) and may result in
degradation of the physical properties of the paint film. This
degradation can limit the performance of such coatings,
particularly in an exterior environment. Oil based paints are also
prone to yellowing in the absence of direct sunlight. The tendency
for these paints to yellow is believed to stem from a variety of
atmospheric based reactions of residual unsaturation derived from
the fatty acid segments of the polymer.
[0008] An alternative approach to providing such products with
these reactive functional groups has been to formulate them with a
polymer that contains functional groups that will react with water.
In this case, the products can be formulated to form a crosslinked
structure after application through being exposed to atmospheric
moisture. However, due to their inherent moisture sensitivity,
great care needs to be taken to exclude moisture during the
manufacture, packaging and storage of such products. Despite
exercising care to exclude moisture from the products, moisture
cure products often have a limited shelf-life.
[0009] Coatings and adhesives are also commonly provided in a
two-part form where one part includes a polymer which contains
functional groups that are reactive toward functional groups of a
polymer contained in the other part. In this case, each part is
mixed prior to application, and crosslinking occurs
post-application through reaction of the respective functional
groups provided from each part. The two-part coating and adhesive
formulations have the advantage of being generally less sensitive
to moisture and therefore often have a good shelf-life. However, by
virtue of their reactivity, the individual components cannot be
provided in the form of a single-part composition, as would be most
convenient. Furthermore, once the two parts are mixed the product
must be used within a relatively short time frame.
[0010] Although the aforementioned moisture cure and two-part
coating and adhesive products effectively form post-application
crosslinked polymeric structures, the reactive functional groups
used to provide the crosslinking sites can render the products
toxic. For example, reactive functional groups commonly used in
such products include isocyanates, amines, epoxides and cyano
acrylate esters, Accordingly, there can be occupational health and
safety risks associated with both the manufacture and use of such
products. Furthermore, the monomers comprising the reactive
functional groups used in such products are generally relatively
expensive.
[0011] Another common formulating technique used to achieve
post-application crosslinking is to provide products in a two-part
form where one part contains a radical initiator and the other part
contains a crosslinkable polymer composition. In this case, the
initiator is mixed with the polymer composition prior to
application, the mixture is then generally immediately applied to a
substrate and crosslinking occurs post-application through a
radical mediated crosslinking reaction that is promoted by the
initiator. As with the previous formulating techniques, this
technique also provides for an effective means to achieve
post-application crosslinking. However, such polymer compositions
are prone to premature and spontaneous crosslinking, the process of
which is very exothermic and potentially explosive. These polymer
compositions therefore typically need to be formulated with
inhibitors to prevent this. Despite the use of inhibitors, the
polymer compositions often have a limited shelf-life. Furthermore,
initiators commonly used in these products, such as those which
contain a peroxy linkage, are typically quite toxic and potentially
explosive in their own right.
[0012] Accordingly, there remains a need to provide an alternative
method for preparing crosslinked polymers that can overcome or
alleviate at least some of the disadvantages associated with the
aforementioned methods.
SUMMARY OF THE INVENTION
[0013] The present invention provides a method of preparing a
crosslinked polymer, which method comprises polymerising branched
polyunsaturated monomers by a metathesis polymerisation reaction,
wherein the branched polyunsaturated monomers contain acyclic
ethylenically unsaturated groups that are capable of undergoing
polymerisation by a metathesis reaction such that the metathesis
polymerisation produces a crosslinked polymer and substantially no
non-volatile ethylenically unsaturated by-products.
[0014] Typically, the branched polyunsaturated monomers referred to
herein will comprise an atom or core to which is attached at least
three moieties, at least three of which contain one or more acyclic
ethylenically unsaturated groups that are capable of undergoing
polymerisation by a metathesis reaction.
[0015] It has now been found that branched polyunsaturated monomers
can be polymerised by a metathesis pathway to afford a crosslinked
polymer structure. The method of the invention is particularly
suited for preparing crosslinked polymers that can be used in
polymer-based coatings and adhesives, and can be readily employed
to provide post-application crosslinking.
[0016] As will be discussed in more detail below, the branched
polyunsaturated monomers can also be polymerised in conjunction
with other unsaturated monomers such as diene monomers.
[0017] Those skilled in the art will appreciate that metathesis
polymerisation reactions afford a polymer product and an
ethylenically unsaturated compound as by-product. In forming
crosslinked polymers in accordance with the invention, it is
important that the metathesis polymerisation affords substantially
no non-volatile ethylenically unsaturated by-products. In other
words, in addition to the crosslinked polymer, substantially all
by-products of the metathesis polymerisation are volatile
ethylenically unsaturated by-products. By being volatile, the
ethylenically unsaturated by-products can be more readily separated
from the reaction mixture. This not only promotes formation of the
crosslinked polymer, but advantageously also allows for the
crosslinked reaction product to be effectively used in, for
example, paint, adhesive, filler, primer and sealant products etc
(hereinafter simply referred to as coating(s) and adhesive(s) or
coating and adhesive products).
[0018] Formation of non-volatile ethylenically unsaturated
by-products in the metathesis polymerisation reaction is likely to
result in the crosslinked reaction product being unsuitable for use
as coating and adhesive products. In particular, the presence of
such non-volatile ethylenically unsaturated by-products in coatings
and adhesives can prevent them from drying (i.e. they remain
tacky), can reduce or inhibit their adhesive or bonding properties,
and can in general reduce their physical and/or mechanical
properties.
[0019] It will be appreciated that whether a given ethylenically
unsaturated by-product is non-volatile or volatile will be
dependant on both the pressure and temperature at which this
property is assessed. In the context of the invention, the terms
"non-volatile" and "volatile" are not intended to refer to absolute
qualities of a given ethylenically unsaturated by-product, but
rather they are to be used as a practical guide in considering the
suitability of crosslinked polymer for use as a coating or
adhesive. Thus, those metathesis polymerisation reactions that
afford substantially no non-volatile ethylenically unsaturated
by-products are likely to provide crosslinked polymers that are
suitable for use as coatings or adhesives. In this context,
"substantially no" will generally mean less that 15 wt %,
preferably less than 10 wt %, more preferable less than 5 wt % of
non-volatile ethylenically unsaturated by-products, relative to the
total mass of ethylenically unsaturated by-products produced by the
metathesis polymerisation reaction.
[0020] As a convenient point of reference only, in the context of
coatings and adhesives, a person skilled in the art might consider
the ethylenically unsaturated by-products to be "non-volatile" if
they are not vaporised at atmospheric pressure from a coating or
adhesive comprising a crosslinked polymer formed in accordance with
the invention at (1) room temperature (ca. 15-35.degree. C.) within
24 hours, (2) about 150.degree. C. within about 10 minutes, or (3)
about 230.degree. C. within about 30 seconds (i.e. common drying
regimes for using such products).
[0021] Alternatively, as a convenient point of reference only, in
the context of coatings and adhesives a person skilled in the art
might consider the ethylenically unsaturated by-products to be
"non-volatile" if they contained more than about 12 carbon atoms.
In other words, the ethylenically unsaturated by-products
preferably contain 2 to about 12, more preferably 2 to about 9
carbon atoms.
[0022] Accordingly, the present invention further provides a method
of preparing a crosslinked polymer suitable for use as or as part
of a coating or adhesive, which method comprises polymerising
branched polyunsaturated monomers by a metathesis polymerisation
reaction, wherein the branched polyunsaturated monomers contain
acyclic ethylenically unsaturated groups that are capable of
undergoing polymerisation by a metathesis reaction such that the
metathesis polymerisation produces a crosslinked polymer.
[0023] A notable advantage provided by the invention is that the
crosslinked polymers may be prepared from a diverse array of
monomers. In particular, the monomers used need only contain
relatively inert acyclic ethylenically unsaturated groups. Thus,
such monomers will generally be less toxic than those used to
prepare conventional crosslinked polymers, and also generally less
prone to premature spontaneous crosslinking. Furthermore, suitable
monomers may be provided from relatively inexpensive sustainable
resources such as natural oils.
[0024] In preparing the crosslinked polymers in accordance with the
invention, it may be preferable to use branched polyunsaturated
monomers that contain terminal or near terminal acyclic
ethylenically unsaturated groups. By using such monomers, formation
of non-volatile ethylenically unsaturated by-products can
advantageously be reduced if not substantially avoided. By the
expression "terminal or near terminal" is meant that the acyclic
ethylenically unsaturated groups can be located at the end of an
organic moiety (i.e. a vinyl group), or within 6 atoms, preferably
within 4 atoms from the end of such a moiety. For example, the
unsaturated group(s) may be located within 6 carbon atoms at the
end of an organic moiety designated R, i.e. R--C.dbd.C--C--C--C--C,
R--C--C--C.dbd.C--C--C, R--C--C--C--C.dbd.C--C, or
R--C--C--C--C--C.dbd.C.
[0025] Branched polyunsaturated monomers that contain terminal or
near terminal acyclic ethylenically unsaturated groups may be
prepared by any suitable means. However, the use of
cross-metathesis reactions to prepare these monomers has been found
to be particularly convenient.
[0026] Accordingly, the invention also provides a method of
preparing a crosslinked polymer, which method comprises: [0027] 1)
preparing branched polyunsaturated monomers having terminal or near
terminal acyclic ethylenically unsaturated groups that are capable
of undergoing polymerisation by a metathesis reaction, by
subjecting a compound comprising one or more acyclic ethylenically
unsaturated groups to a cross-metathesis reaction with a low
molecular weight ethylenically unsaturated compound to produce a
compound comprising one or more terminal or near terminal acyclic
ethylenically unsaturated groups which: [0028] (a) can be used as
the branched polyunsaturated monomers, and/or [0029] (b) is reacted
with one or more other compounds to provide a compound which can be
used as the branched polyunsaturated monomers; and [0030] 2)
polymerising the branched polyunsaturated monomers by a metathesis
polymerisation reaction to afford the crosslinked polymer.
[0031] Through use of such a cross metathesis reaction pathway,
branched polyunsaturated monomers derived from inexpensive natural
oils can advantageously be used to prepare unique crosslinkable
coatings and adhesives. Notably, such methodology enables many so
called non-drying or semi-drying natural oils, that have to date
been unsuitable for use in coatings and adhesives, to now be used.
For example, mono unsaturated triglycerides (i.e. one double bond
in each fatty acid arm of the triglyceride) can be readily employed
to prepare crosslinkable coatings and adhesives.
[0032] The invention therefore also provides a coating (such as a
paint) or adhesive product comprising branched polyunsaturated
monomers that contain acyclic ethylenically unsaturated groups that
are capable of undergoing polymerisation by a metathesis reaction
to form a crosslinked polymer, and an olefin metathesis
catalyst.
[0033] Other aspects of the invention are described below.
DETAILED DESCRIPTION OF THE INVENTION
[0034] Unless otherwise stated, where the term "acyclic" is used
herein in conjunction with expressions such as "diene monomer",
"ethylenically unsaturated group", or "ethylenic unsaturation", or
similar expressions, it is intended for this to be a reference to
the nature of the unsaturated character of that group or monomer
rather than any other facet of that monomer or moiety which
contains that group. Thus, a moiety containing an "acyclic"
ethylenically unsaturated group may also contain cyclic groups, but
the ethylenically unsaturated group per se is acyclic in character
in that it is not contained within a cyclic structure. In the case
of an "acyclic" diene monomer, only the ethylenically unsaturated
groups need be acyclic in character.
[0035] The polymerisation of acyclic diene monomers by metathesis
is generally well known and is commonly referred to as ADMET
(acyclic diene metathesis) polymerisation. As with all metathesis
reactions, ADMET polymerisation involves the reaction of a
transition metal alkylidene complex, more commonly referred to as
an olefin metathesis catalyst, with an acyclic ethylenically
unsaturated group. Mechanistically, propagation of a polymer chain
by ADMET polymerisation is believed to involve the formation of two
metallocyclobutane intermediate species, with the polymer chain
being ejected from the active metal species during each propagation
step. The propagation step also involves the liberation of an
ethylenically unsaturated reaction by-product, preferably a
volatile molecule such as ethylene, which needs to be removed from
the reaction environment to promote polymerisation.
[0036] ADMET polymerisation reactions inherently afford polymers
with a linear unsaturated backbone. Studies have shown that the
unsaturated character of these polymers may be used in secondary
reactions to provide crosslinking sites. In particular, polymers
derived from ADMET polymerisation reactions have been subjected to
conventional thermal, ultraviolet and chemical modification
processes to afford crosslinked polymer structures (Macromolecules,
1992, 25, 2049-2052).
[0037] It has now been found that a metathesis reaction pathway can
be used to directly prepare crosslinked polymers in an effective
and efficient manner,
[0038] In accordance with the invention, crosslinked polymers can
be prepared by polymerising branched polyunsaturated monomers. The
branched polyunsaturated monomers will typically have at least one
atom or core to which is attached at least three moieties, at least
three of which contain acyclic ethylenic unsaturation. The atom or
core may have more than three moieties attached to it, and more
than three moieties may contain acyclic ethylenic unsaturation.
[0039] To more clearly describe what is intended by the branched
polyunsaturated monomers having "an atom or core to which is
attached at least three moieties", the monomers can be conveniently
represented as comprising at least the general structural unit
(I):
BR.sup.1R.sup.2R.sup.3 (I)
where B represents an atom or core, and where each moiety R.sup.1,
R.sup.2 and R.sup.3, which may be the same or different, contains
at least one acyclic ethylenically unsaturated group which is
capable of undergoing polymerisation by a metathesis reaction.
[0040] The atom or core (B) must be cable of having at least three
moieties attached to it, and as such may simplistically be viewed
as a branch point or junction. The branched polyunsaturated
monomers used in accordance with the invention may have more than
one such branch point or junction. In this case, the further branch
point(s) or juncture(s) may be provided by other atoms or cores
present in one or more of the moieties attached to the atom or core
(B) in general structural unit (I). Accordingly, the branched
polyunsaturated monomers may comprise both atoms and cores that
provide for branch points or junctions.
[0041] Where B in the general structural unit (I) is an atom, it
will generally be C, Si or N. In the case where the atom is C or
Si, the branch atom may have a fourth moiety attached to it which
can also contain at least one acyclic ethylenically unsaturated
group that is capable of undergoing polymerisation by a metathesis
reaction.
[0042] By the term "core", as used in connection with the branched
polyunsaturated monomers, is meant a molecular structure to which
the at least three moieties are attached. For example, the core
might be a cyclic aromatic or non-aromatic structure such as that
afforded by a benzene or cyclohexane ring, fused derivatives
thereof, or possibly a collection of such cycles coupled together
by alkyl groups. The core might also be an oligomeric or polymeric
structure. In contrast with the general structural unit (I) in
which B is an atom, where B is a "core" the number of moieties
which contain at least one acyclic ethylenically unsaturated group
that can be attached to the core can be considerably higher than
four.
[0043] As mentioned above, the branched polyunsaturated monomers
will typically comprise at least three moieties attached to an atom
or core, each of which contain at least one acyclic ethylenically
unsaturated group that is capable of undergoing polymerisation by a
metathesis reaction. By having the ethylenically unsaturated groups
configured in this manner, the monomers can advantageously be
polymerised by a metathesis reaction to directly afford a
crosslinked polymer. In contrast, polymerisation of acyclic diene
monomers through a conventional ADMET polymerisation reaction
inherently affords polymers having a linear backbone.
[0044] Where an acyclic ethylenically unsaturated group is said to
be "capable of undergoing polymerisation by a metathesis reaction"
or reference is given to a crosslink reaction occurring "through a
metathesis mediated reaction pathway", it is intended for these
statements to mean that the acyclic ethylenically unsaturated
groups of the monomer can react or does react with a metathesis
catalyst in the process of forming a crosslinked polymer
structure.
[0045] Those skilled in the art will appreciate the factors that
may effect the susceptibility of a given acyclic ethylenically
unsaturated group to undergo polymerisation by a metathesis
reaction. For example, moieties which contain the acyclic
ethylenically unsaturated groups can impart steric and/or
electronic effects that influence the reactivity of the unsaturated
groups toward a metathesis catalyst. Furthermore, and as discussed
above, to promote the metathesis reaction the ethylenically
unsaturated by-product of the reaction, which is itself derived
from the monomers being polymerised, should be sufficiently
volatile so that it can be removed from the reaction medium.
[0046] Generally, the susceptibility of an acyclic ethylenically
unsaturated group to undergo polymerisation by a metathesis
reaction can be enhanced by reducing steric crowding in the general
proximity of the unsaturated group. It may therefore be preferable
that the ethylenically unsaturated group contained in each of the
at least three moieties attached to the atom or group is a terminal
or near terminal acyclic ethylenically unsaturated group, and
possibly an unsubstituted terminal or near terminal acyclic
ethylenically unsaturated group.
[0047] To reduce, if not substantially avoid, the formation of
undesirable non-volatile ethylenically unsaturated by-products
during the course of the crosslinking reaction, it can be
preferable that substantially all of ethylenically unsaturated
groups in the monomer are terminal or near terminal acyclic
ethylenically unsaturated groups, and possibly unsubstituted (i.e.
--CH.dbd.CH-- or --CH.dbd.CH.sub.2) terminal or near terminal
acyclic ethylenically unsaturated groups.
[0048] With an understanding of the function of the acyclic
ethylenically unsaturated groups and how they might be configured
within the branched monomers, those skilled in the art will also
appreciate that apart from the acyclic unsaturated group itself,
the structure and composition of the remainder of the monomer is
not particularly important with respect to the crosslinking
process. Accordingly, any organic group can generally function as a
moiety provided it can be attached to an atom or core and contains
at least one acyclic ethylenically unsaturated group which is
susceptible to undergoing polymerisation by a metathesis reaction.
The moieties may therefore comprise cyclic and/or branched and/or
linear groups, contain or be substituted with a variety of
functional groups, contain one or more hetero atoms such as N, O,
S, P etc., and as mentioned above, may even contain one or more
further atoms or cores (B) as hereinbefore defined.
[0049] One advantage afforded by the invention is that the
crosslinked polymers may be prepared using a diverse array of
branched polyunsaturated monomers. Having regard to the forgoing,
those skilled in the art could readily select suitable monomers.
The monomers may have a relatively low molecular weight or can
include oligomeric and polymeric compounds. For example, a branched
polyunsaturated pre-polymer may be used prepare the crosslinked
polymer.
[0050] Oligomeric or polymeric branched polyunsaturated monomers
that can be used in accordance with the invention may have quite
complex structures. For example, the monomers may be in the form of
a polymer/oligomer that has a branched or linear backbone onto
which is attached at least three moieties as pendant groups,
wherein at least three of the pendant groups each contain at least
one acyclic ethylenically unsaturated group that is capable of
undergoing polymerisation by a metathesis reaction. In practice,
such a polymer/oligomer backbone may contain many of these pendant
groups, for example greater than 20.
[0051] Polymeric/oligomeric branched polyunsaturated monomers may
be prepared using conventional polymerisation techniques such as
free radical and condensation and metathesis polymerisation
techniques.
[0052] One such approach might be to prepare the
polymericloligomeric branched polyunsaturated monomers using
monomers that when polymerised afford pendant groups which contain
the requisite unsaturated character. In this case, the mode of
polymerisation that is used should enable the pendant groups to
retain the requisite unsaturated character.
[0053] An alternative approach might be to prepare a
polymer/oligomer which has reactive functional groups that may be
subsequently reacted to provide pendant groups having the requisite
unsaturated character. For example, a styrene maleic anhydride
copolymer may be prepared by conventional means and subsequently
reacted with a reagent such as undecylenic alcohol to afford
pendant groups with the requisite unsaturated character.
[0054] In both of the approaches mentioned directly above, the
number of pendant groups that are attached to the polymer backbone
can be advantageously varied through variation of the ratios of
monomers used to prepare the polymer/oligomer.
[0055] The branched polyunsaturated monomers used in accordance
with the invention may also be prepared directly or indirectly
through cross-metathesis reactions. For example, to provide
branched polyunsaturated monomers which contain terminal or near
terminal acyclic ethylenically unsaturated groups, a compound
comprising one or more acyclic ethylenically unsaturated groups
could be subjected to a cross-metathesis reaction with a low
molecular weight ethylenically unsaturated compound. Such compounds
would not generally already comprise three or more terminal or near
terminal acyclic ethylenically unsaturated groups.
[0056] The compound comprising one or more acyclic ethylenically
unsaturated groups may be a branched polyunsaturated compound
having an atom or core to which is attached at least three
moieties, at least three of which contain one or more acyclic
ethylenically unsaturated groups, for example a natural oil. In
this case, the cross-metathesised product would be a branched
polyunsaturated monomer that contains terminal or near terminal
acyclic ethylenically unsaturated groups and could be used to
prepare a crosslinked polymer in accordance with the invention. The
resulting branched polyunsaturated monomer might also be reacted
with one or more other compounds or reagents, for example to build
the molecular weight of the compound (i.e. to form a pre-polymer).
This "modified" branched polyunsaturated monomer might then be used
to prepare a crosslinked polymer in accordance with the
invention.
[0057] A specific example of a cross-metathesis reaction described
directly above would be the cross-metathesis reaction of a
vegetable oil with ethene as shown below.
##STR00001##
[0058] The compound comprising one or more acyclic ethylenically
unsaturated groups may also be a branched polyunsaturated compound
as described directly above but in the form of a pre-polymer. For
example, the compound might be an alkyd resin prepared from the
reaction of a monoglyceride with phthalic anhydride. The resin may
be subjected to a cross-metathesis reaction with a low molecular
weight ethylenically unsaturated compound to afford an alkyd resin
comprising terminal or near terminal acyclic ethylenically
unsaturated groups that could then be used to prepare a crosslinked
polymer in accordance with the invention. An idealised structure of
such an alkyd monomer is shown below.
##STR00002##
[0059] Alternatively, the cross-metathesis reaction might be used
to prepare a precursor compound that can be reacted with one or
more compounds to form a branched polyunsaturated monomer that may
be used to prepare a crosslinked polymer in accordance with the
invention. For example, the compound comprising one or more acyclic
ethylenically unsaturated groups may be a fatty acid or fatty acid
ester derived from natural oils. Such a compound could be subjected
to a cross-metathesis reaction with a low molecular weight
ethylenically unsaturated compound to afford a terminal or near
terminal ethylenically unsaturated fatty acid or fatty acid ester.
The resulting compound could then be reacted with one or more
compounds to afford the branched polyunsaturated monomers that
could be used to prepare a crosslinked polymer in accordance with
the invention. In this case, fatty acids or fatty acid esters that
would not otherwise be used in coatings and adhesives products can
be converted into a valuable resource for such products.
[0060] A specific example of a cross-metathesis reaction described
directly above would be the cross-metathesis reaction of a fatty
acid ester with ethene as shown below.
##STR00003##
[0061] Those skilled in the art will appreciate that the
cross-metathesis reactions described above also produce an
ethylenically unsaturated reaction by-product. However, unlike the
ethylenically unsaturated reaction by-products that can be produced
during formation of the crosslinked polymer, the desired terminal
or near terminal ethylenically unsaturated compound and the
ethylenically unsaturated reaction by-products produced during such
cross-metathesis reactions can generally be readily separated from
each other.
[0062] By "natural oils" is meant oils commonly referred to as
vegetable oils, and even fish oil. Such oils must comprise at least
one ethylenically unsaturated group, and will generally comprise
triglycerides. Examples of suitable natural oils include, but are
not limited to, canola oil, soybean oil, flax or linseed oil, tung
oil, castor oil, and combinations thereof.
[0063] Unsaturated fatty acid and fatty acid esters derived from
such oils can also be used in accordance with the invention.
[0064] By "low molecular weight ethylenically unsaturated compound"
in the context of a cross-metathesis reaction is meant a
C.sub.2-C.sub.6 ethylenically unsaturated compound.
[0065] Cross-metathesis reactions using low molecular weight simple
alkenes have been studied for many years. Of the simple alkenes
explored in these cross-metathesis reactions, ethene, as employed
in the reactions depicted above, has received the most attention.
Cross-metathesis reactions involving ethene are generally referred
to as ethenolysis reactions.
[0066] Despite considerable research being devoted to studying such
ethenolysis reactions, there remain significant problems associated
with using this technique to prepare terminal unsaturated
compounds, and in particular terminal unsaturated carbonyl
compounds. These problems can include poor conversion and
selectivity, the need for relatively high catalyst loadings, long
reaction times and some limitations on the type of feedstocks.
[0067] One significant problem with ethenolysis reactions that has
to date proven difficult to overcome is the generation of a
methylidene intermediate in the catalytic cycle. Ruthenium
methylidene complexes have been shown to have relatively low
initiation rates in olefin metathesis reactions. For reactions in
which methylidene intermediates are present, sustained metathesis
activity can be achieved by increasing temperature. However, this
approach also increases the rate of catalyst decomposition
resulting in the need for higher catalyst loadings.
[0068] A further problem associated with ethenolysis reactions is
that the products of the reaction (i.e. terminal olefins) and the
ethene can compete with internal olefins present in the starting
material in binding to the metathesis catalysts. This results in
long reactions times and also has an impact on catalyst loading as
significant decomposition of the catalyst can occur during the
course of the reaction.
[0069] As mentioned, there can be some limitations on the type of
feedstocks that may be used in ethenolysis reactions. For example,
natural oils that contain conjugated polyunsaturated fatty acids,
such as tung oil, are typically poorly converted in ethenolysis
reactions. This problem can also extend to other polyunsaturated
oils that are not conjugated. For example, ruthenium-based olefin
metathesis catalysts have a tendency to catalyse olefin
isomerization reactions in addition to olefin metathesis reactions,
Thus, 1,4-dienes commonly found in polyunsaturated natural oils can
isomerise in the presence of the metathesis catalyst to give
conjugated olefins and hence the same problems described above.
[0070] Accordingly, there remains a need to provide an alternative
method for preparing acyclic unsaturated compounds that can
overcome or alleviate at least some of the disadvantages associated
with the aforementioned ethanolysis reactions.
[0071] The invention further provides a method of preparing near
terminal ethylenically unsaturated carbonyl compounds, which method
comprises subjecting a carbonyl compound comprising an acyclic
ethylenically unsaturated group to a cross-metathesis reaction with
substantially pure 2-butene.
[0072] It has now been found that substantially pure 2-butene can
be used effectively and efficiently in preparing near terminal
ethylenically unsaturated carbonyl compounds. The 2-butene may be
cis or trans, or a combination thereof. The use of 2-butene in
cross metathesis reactions to produce ethylenically unsaturated
carbonyl compounds has been reported. However, such reactions have
afforded particularly low yields. Without wishing to be limited by
theory, it is believed that commercial sources of 2-butene comprise
sufficient quantities of impurities that can poison the olefin
metathesis catalysts used in such reactions (e.g. ruthenium based
metathesis catalysts), Such impurities are believed to at least
comprise 1, 3-butadiene, a poison for acyclic metathesis reactions.
Accordingly, cross metathesis reactions using 2-butene (i.e.
butenolysis) to date have been inefficient and practically
ineffective.
[0073] By using substantially pure 2-butene, cross-metathesis
reactions can now advantageously be performed where the productive
turn over number (TON) is greater than about 5,000, preferably
greater than about 10,000, more preferably greater than about
20,000, most preferably up to 90,000 or higher.
[0074] By "substantially pure" 2-butene is meant that the 2-butene
is sufficiently free of impurities to enable turn over numbers of
greater than about 5,000 to be achieved. Typically, impurities
should be present in an amount no greater than about 0.1 mol %,
relative to 2-butene.
[0075] The use of 2-butene is believed to also advantageously avoid
methylidene intermediates being formed during the catalytic cycle,
thus circumventing the problems associated with methylidene
intermediates in ethenolysis reactions. Another advantage to using
2-butene is that as an internal ethylenically unsaturated compound
it competes to a less extent with unreacted ethylenically
unsaturated carbonyl compounds to bind to the catalyst compared
with ethylene.
[0076] The conversion and selectivity of the butenolysis reactions
can be controlled by the ratio of 2-butene to the ethylenically
unsaturated carbonyl compound. In order to achieve high selectivity
and conversion a large excess of 2-butene over the ethylenically
unsaturated carbonyl compounds should be used, The reaction can be
conducted with or without additional solvent, and preferably either
at elevated temperature (>1.degree. C.) and pressure (>1
atm.) or at low temperature (<1.degree. C.) and atmospheric
pressure.
[0077] Those skilled in the art will appreciate that such
butenolysis reactions will afford near terminal ethylenically
unsaturated carbonyl compounds in which the ethylenically
unsaturated group is located between the second and third atoms of
a pendant group. In other words, the ethylenically unsaturated
group will be a penultimate terminal ethylenically unsaturated
group (i.e. R--C--C--C--C.dbd.C--C).
[0078] The butenolysis reaction in accordance with the invention
may conveniently be preformed using a diverse array of
ethylenically unsaturated carbonyl compounds. By "ethylenically
unsaturated carbonyl compound" is meant an ethylenically
unsaturated compound that comprises one or more carbonyl functional
groups such as an ester, an amide, a ketone, an aldehyde or a
carboxylic acid. Having regard to the forgoing, those skilled in
the art could readily select suitable ethylenically unsaturated
carbonyl compounds for this purpose.
[0079] The butenolysis reaction in accordance with the invention
may conveniently be preformed using unsaturated natural oils, or
fatty acids or fatty acid esters derived therefrom, to prepare near
terminal ethylenically unsaturated carbonyl compounds. The
butenolysis reaction is particularly suited for use in preparing
branched polyunsaturated monomers that may be crosslinked in
accordance with the invention. For example, the butenolysis
reaction may be used to prepare branched polyunsaturated monomers
from linseed oil as illustrated below.
##STR00004##
[0080] The method of preparing a crosslinked polymer in accordance
with invention can advantageously be performed in numerous ways and
under a variety of conditions. Such versatility stems in part from
the ability to provide the branched polyunsaturated monomers in
either a liquid or a solid form, and also the ability to select the
monomers such that they can be polymerised by the metathesis
reaction at ambient temperatures.
[0081] To accelerate the rate of crosslinking and produce tightly
crosslinked and inert coatings, industrial processes, such as the
coating of automotive bodies or continuous coil with crosslinkable
coatings, are often performed at elevated temperature (i.e. up to
about 240.degree. C.). However, for temperature sensitive
substrates or consumer applications where the use of high
temperature is not convenient or not possible, it is highly
desirable to employ crosslinking reactions that are accessible at
room temperature or only with moderate degree heating (i.e.
temperatures less than 100.degree. C.). Such crosslinking reactions
will of course still be accelerated if more heat is applied, but
the main advantage is that the reactions are available for consumer
application. The crosslinking method in accordance with the
invention is particularly well suited for such consumer
applications.
[0082] In performing the method of the invention, the necessary
reagents may be provided in a variety of different two-part
systems. The coatings and adhesives products of the invention may
be conveniently provided in the form of such two-part curable
systems.
[0083] A simple two-part system may comprise a first part which
comprises branched polyunsaturated monomers suitable for reaction
in accordance with the present invention, and a second part which
comprises a metathesis catalyst. The formulations of each part can
readily be mixed prior to application to enable crosslinking to
occur post-application through a metathesis mediated reaction
pathway.
[0084] One advantage such two-part systems may provide over
conventional two part systems is that once the two parts are mixed,
the crosslinking reaction can be retarded simply by enclosing the
mixture in a sealed container. By confining the mixture in this
way, volatile alkene by-products are restricted from leaving the
reaction environment and the metathesis reaction can be retarded.
This in turn can extend the products workable application time post
mixing.
[0085] Depending upon the nature of the monomer and catalyst,
crosslinking may occur at ambient temperatures, or it may be
necessary to apply heat to the mixed two-part formulation to
promote crosslinking. An example of where it may be necessary to
apply heat to promote crosslinking is where the monomer is provided
in solid form. In solid form, the monomer can be conveniently
powdered and applied to a substrate using conventional powder
coating technology. The catalyst can then be applied to the monomer
by a technique such as spraying. Alternatively, due to there being
limited reactivity between the catalyst and the solid monomer, the
catalyst may be combined with the powdered monomer before it is
applied to the substrate. In order to promote crosslinking, the
catalyst/monomer combination can be heated by well known methods
such as inferred (IR) irradiation. Under these circumstances,
sufficient heat is generally applied to cause the monomer to
melt.
[0086] As an alternative two-part system, the first part may
comprise branched polyunsaturated monomers and acyclic diene
monomers, and the second part may comprise the metathesis catalyst.
This two-part system may be utilised in much the same way as the
system discussed above. However, in this case the presence of the
acyclic diene monomers provides considerable flexibility in being
able to adjust the composition and architecture of the resulting
crosslinked polymer. Notably, the crosslink density of the
resulting crosslinked polymer can be readily adjusted. For example,
by providing the first part with diene monomers the crosslink
density of the resulting crosslinked polymer can be reduced.
Conversely, by providing the first part with little or no diene
monomers the crosslink density of the resulting crosslinked polymer
can be increased.
[0087] Accordingly, the method of the invention may further
comprise polymerising acyclic diene monomers by the metathesis
polymerisation reaction.
[0088] It should also be noted that the crosslink density of the
crosslinked polymers prepared in accordance with the invention can
also be varied by changing the nature of the branched
polyunsaturated monomers. In this case, by having the acyclic
ethylenically unsaturated groups of the monomer in closer proximity
to each other the crosslink density of the resulting crosslinked
polymer will generally be higher than if the unsaturated groups
were more spaced apart.
[0089] Thus, through variation of the nature of the branched
polyunsaturated monomer and the use of acyclic diene monomers, the
method provides for considerable flexibility in being able to
adjust the composition and architecture of the resulting
crosslinked polymer.
[0090] When used in conjunction with the branched polyunsaturated
monomers in preparing the crosslinked polymers, the acyclic diene
monomers should also react with the metathesis catalyst during the
crosslinking process. Accordingly, the diene monomers must have at
least two ethylenically unsaturated groups that are susceptible to
undergoing polymerisation by a metathesis reaction. Suitable
acyclic diene monomers are generally well known and readily
available. In particular, those monomers suitable for use in a
conventional ADMET polymerisation may be used as acyclic diene
monomers.
[0091] Acyclic diene monomers used in conjunction with the branched
polyunsaturated monomers can be in either liquid or solid form.
Where both the branched acyclic polyunsaturated monomer and the
diene monomer are in solid form, both monomers can conveniently be
melt mixed, for example by extrusion, and subsequently powdered for
use in a powder coating process as described above.
[0092] An alternative two-part system may also comprise a first
part which comprises branched polyunsaturated monomers suitable for
reaction in accordance with the present invention, and a second
part which comprises a polymer prepared by ADMET polymerisation. In
this case, it is important that the ADMET derived polymer retains
an active catalyst component. By "retains an active catalyst
component" is meant that the polymer reaction product of the ADMET
polymerisation reaction has associated with it metathesis catalyst
which is capable of promoting further polymerisation reactions.
[0093] In this particular two-part system, the formulations of each
part may be mixed prior to application to enable to crosslinking
occur post-application through a metathesis mediated reaction
pathway. However, unlike the previous two-part systems, the
catalyst component is provided by an ADMET derived polymer. In this
case, the catalyst in effect remains dormant until the components
of each part are combined. This two-part system may be utilised in
much the same way as the systems described above. For example, the
monomers and ADMET derived polymer may be provided in solid form
and applied by powder coating techniques. Alternatively, the
monomers and/or ADMET derived polymer may be solvated with a
suitable solvent to provide for a liquid curable system.
[0094] The method of preparing a crosslinked polymer in accordance
with the invention may be performed as a bulk polymerisation or in
an organic solvent. By providing the branched polyunsaturated
monomers as low viscous liquids, or in solid form, the two-part
systems described above may be formulated using little if no
organic solvent. The ability to use little if no organic solvent in
such systems is a particularly advantageous given the onerous
legislative requirements regarding the permissible volatile organic
content (VOC) of coating and adhesive products that apply in many
countries.
[0095] The method of crosslinking polymers in accordance with the
invention can be readily applied to provide effective coatings and
adhesives. The coating and adhesives in accordance with the
invention comprise branched polyunsaturated monomers that contain
acyclic ethylenically unsaturated groups that are capable of
undergoing polymerisation by a metathesis reaction to form a
crosslinked polymer, and an olefin metathesis catalyst. Those
skilled in the art will have an understanding of other suitable
formulation components that may also be included in the coating and
adhesives. Examples of such formulation components include, but are
not limited to, thickeners, antifungal agents, UV absorbers,
extenders, pigments and tinting agents.
[0096] The cured product formed from the coatings and adhesives in
accordance with the invention may comprise polymer material not
formed through the metathesis crosslinking reaction. Accordingly,
the coatings and adhesives may be formulated as a blend with other
polymers and/or monomers that are not formed from or take part in
the metathesis polymerisation reaction.
[0097] A notable advantage of the coatings and adhesives in
accordance with the invention is that the products crosslinked
polymer structure is not formed via autoxidation. As previously
mentioned, the process of autoxidation can continue for a long
period of time (i.e. post drying of the coating or adhesive) and
may result in degradation of the physical properties of the coating
or adhesive. For example, in oil based paints degradation of the
crosslinked polymer can lead to pigment particles at the surface of
the paint film becoming exposed and result in a problem known as
chalking. Oil based paints are also prone to yellowing due to the
presence or formation of residual conjugated unsaturation in the
polymer that forms the paint film.
[0098] Unlike the progressive nature of autoxidation, the
metathesis mediated reaction pathway that operates in the
crosslinking method of the invention occurs within a finite time
frame uniformly throughout the composition. Furthermore, feedstock
monomers for the metathesis crosslinking reactions are unlikely to
contain or give rise to a residual conjugated unsaturation in the
resulting crosslinked polymer product. Thus, the crosslinked
polymer products in accordance with the invention will typically
maintain their physical properties and be less prone to yellowing
over time compared with products formed by conventional means.
[0099] The present invention involves the use of an olefin
metathesis catalyst. Those skilled in the art could readily select
and obtain suitable catalysts to perform the invention. Examples of
suitable olefin metathesis catalyst include, but are not limited
to, Grubbs Catalyst 1st generation, or
Benzylidene-bis(tricyclohexylphosphine)dichlororuthenium, Grubbs
Catalyst 2nd Generation, or
Benzylidene[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro-
(tricyclohexylphosphine)ruthenium, and Hoveyda-Grubbs Catalyst 2nd
Generation, or 1,3
-Bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxyp-
henylmethylene)ruthenium.
[0100] For butenolysis reactions and cross-linking with butenolysis
products, Grubbs Catalyst 2nd Generation and Hoveyda-Grubbs
Catalyst 2nd Generation are preferred.
[0101] The olefin metathesis catalyst may be provided in any
suitable form that enables it to promote polymerisation. For
example, the catalyst may be combined with a suitable carrier
material such as a solvent or perhaps a solid and formed into a
tablet. It will be appreciated that any such carrier material
should be compatible with other components of the curable
systems.
EXAMPLES
Example 1
Butenolysis of Triolein
[0102] A schlenk tube equipped with a magnetic stirrer bar was
evacuated then filled with argon and placed in a methanol bath
which was cooled to -5.degree. C. The tube was charged with
cis-2-butene (1.30 g, 23.2 mmol) and triolein (0.75 mL, 7.7 mmol).
A solution of Hoveyda-Grubbs Second Generation Catalyst (0.145
.mu.g, 2.32 nmol) in dichloromethane (10 .mu.L) was added to the
tube and the mixture was stirred using a magnetic stirrer for 256
minutes. After this time the reaction was quenched by addition of
ethyl vinyl ether (500 .mu.L). A sample of the product was
trans-esterified with methanol by conventional means and analysis
of the trans-esterification product by Gas Chromatography (GC)
showed a conversion of >90% the oleic chains to 9-undecenoic
chains. This conversion equates to a TON of >90,000 for the
catalyst.
Example 2
Butenolysis of methyl oleate with 2-butene of Varying Purity
[0103] Schlenk tubes equipped with a magnetic stirrer bar was
evacuated then filled with argon and placed in a methanol bath
which was cooled to -5.degree. C. Various samples were prepared
using samples of 2-butene from various sources;
[0104] Sample A (comparative): cis+trans 2-butene (contains 2.6% of
1,3 butadiene)
[0105] Sample B: cis-2-butene (free of 1,3 butadiene)
[0106] Sample C (comparative): cis 2-butene (free of 1,3 butadiene)
doped with 2% butadiene
[0107] The quantity of 2-butene added in each case was the same
(1.30 g, 23.2 mmol). A quantity of singly distilled methyl oleate
(1.45 mg, 4.88 mmol) and a solution of Hoveyda-Grubbs Second
Generation Catalyst (0.145 .mu.g, 2.32 nmol) in dichloromethane (10
.mu.L) was added to the tube and the mixture was stirred using a
magnetic stirrer for 256 minutes. After this time the reaction was
quenched by addition of ethyl vinyl ether (500 .mu.L). The samples
were analysed by GC and the degree of conversion of the oleic
chains to 9-undecenoic chains compared.
[0108] Results:
TABLE-US-00001 Sample A trace << 1% conversion Sample B
>90% conversion Sample C trace << 1% conversion
Example 3
Butenolysis of methyl oleate
[0109] A stainless steel autoclave with a glass liner was equipped
with a magnetic stirrer bar and charged with ethyl oleate (0.34 g,
1.1 mmol) and Second Generation Grubbs Catalyst (9.3 mg, 0.11
.mu.mol). The autoclave flushed with argon. The autoclave was
evacuated and then pressurised with cis-2-butene to a pressure of
15 psi. The autoclave was heated at 60.degree. C. with stirring
overnight. The pressure was then released and ethyl vinyl ether (50
.mu.L) added to the reaction mixture. A sample of the product was
trans-esterified with methanol by conventional means and analysis
of the trans-esterification product by GC showed a conversion of
>85% of the oleic chains to 9-undecenoic chains.
Example 4
Butenolysis of Canola Oil
[0110] A 2 L round bottomed flask equipped with a magnetic stirrer
bar was immersed in a methanol bath. The flask was charged with
canola oil (80.97 g), then evacuated and the oil stirred rapidly
for 1 hour. The flask was then filled with argon and the methanol
bath was cooled to -7.degree. C. The flask was then charged with
cis+ trans-2-butene (204.5 g, 3.65 mol). A solution Hoveyda-Grubbs
Second Generation Catalyst (11.4 mg, 0.18 .mu.mol) in
dichloromethane (1 mL) was added to the flask and the mixture was
stirred using a magnetic stirrer for 64 minutes. After this time
tricyclohexylphosphine (0.15 g) was added to the mixture. The
temperature of the bath was raised slowly to .about.40.degree. C.
and the volatiles collected by distillation. A small sample of the
product was trans-esterified with methanol by conventional means
and analysis of the trans-esterification product by GC showed a
conversion of >95% the unsaturated fatty acid chains to
9-undecenoic chains.
Example 5
[0111] Butenolysis of a Soya-Based alkyd Resin
[0112] A 2 L round bottomed flask equipped with a magnetic stirrer
bar was immersed in a methanol bath cooled to .about.10.degree. C.
The flask was evacuated and filled with argon. The flask was
charged with a de-gassed solution of a soya-based alkyd resin (90
g) in dichloromethane (100 mL), cis+ trans-2-butene (166 g, 2.96
mol) and Hoveyda-Grubbs Second Generation Catalyst (0.10 g, 16.0
mmol). The mixture was stirred using a magnetic stirrer for
.about.90 minutes. After this time additional Hoveyda-Grubbs Second
Generation Catalyst (0.10 g, 16.0 mmol) was added to the reaction
and stirring was continued for a further 60 minutes.
Tricyclohexylphosphine (0.10 g) was added to the mixture. The
temperature of the bath was raised slowly to room temperature and
the volatiles were collected by distillation. Air was bubbled
through the remaining solution overnight. A small sample of the
product was trans-esterified with methanol by conventional means
and analysis of the trans-esterification product by GC showed a
conversion of >90% the unsaturated fatty acid chains to
undec-9-enoic chains, Additional volatile compounds were removed
from the product by heating the product at 150.degree. C. in a high
vacuum for 15 minutes.
Example 6
Preparation of 2,2-bis((undec-10-enoyloxy)methyl)propane-1,3-diyl
diundec-10-enoate
[0113] Trimethylolpropane (2.73 g, 20.34 mmol), undecenylenic acid
(15.0 g, 81.39 mmol, 4 equiv.) and DMAP (0.99 g, 8.136 mmol, 0.4
equiv.) were dissolved in tetrahydrofuran (150 ml) and the mixture
was cooled to 0.degree. C. DCC (16.77 g, 81.39 mmol, 4 equiv.) in
tetrahydrofuran (45 ml) was added drop-wise to the mixture and kept
at 0.degree. C. for 30 mins then allowed to warm to 20.degree. C.
and stirred for 3 days. The mixture was filtered (to remove
N,N-dicyclohexyl urea) to remove precipitate. The remaining clear
liquid was reduced under partial pressure. The residue was taken up
in ether, washed with sodium carbonate (10% aqueous solution),
brine, dried over magnesium sulfate, filtered and reduced under
partial pressure. The crude material was purified by flash
chromatography (ethyl acetate/hexane 5/95) to give 9.55 g (74%) of
ethane-1,1,1-triyl triundec-10-enoate as a yellow oil; IR (film)
3467, 3076, 2922, 2855, 2120, 1746, 1640, 1464, 1417, 1386, 1355,
1236, 1158, 1116, 1056, 994, 909, 783, 724 cm.sup.-1; .sup.1H NMR
(CDCl.sub.3): .delta.=5.90-5.72 (m, 3H), 5,04-4.87 (m, 6H), 4.00
(s, 6H), 2.28 (t, 6H, J=2.26 Hz), 2.07-1.99 (m, 6H), 1.62-1.55 (m,
6H), 1.52-1.43 (m, 2H), 1.42-1.34 (m, 30H), 0.88 (t, 3H, J=2.12
Hz); .sup.13C NMR (CDCl.sub.3): .delta.=173.2, 138.9, 114.0, 63.6,
40.5, 34.1, 33.6, 29.2, 29.1, 29.0, 28.9, 28.7, 24.8, 23.0, 7.2;
MS-ESI m/z 655.6 (M+Na.sup.+). Anal. Calcd for
C.sub.39H.sub.68O.sub.6: C, 74.00; H, 10.83. Found; C, 73.98; H,
11.01.
Example 7
Preparation of
2-ethyl-2-((undec-10-enoyloxy)methyl)propane-1,3-diyl
diundec-10-enoate
[0114] Pentaerythrilol (2.94 g, 21.59 mmol), undecenoic acid (20.0
g, 108.53 mmol, 5 equiv.) and DMAP (1.32 g, 10.85 mmol, 0.5 equiv.)
were dissolved in THF (150 ml) and the mixture was cooled to
0.degree. C. DCC (22.28 g, 108.53 mmol, 5 equiv.) in THF (50 ml)
was added dropwise to the mixture and kept at 0.degree. C. for 30
minutes then allowed to warm to 20.degree. C. and stirred for 3
days. The mixture was filtered then reduced under partial pressure.
The residue was taken up in ether (200 ml) and washed with
Na.sub.2CO.sub.3 (10% aqueous solution), brine, dried over
MgSO.sub.4, filtered and reduced under partial pressure. The crude
material was purified by flash chromatography (EtOAc/Hexane 5/95)
to give 12.65 g (72%) of
2-ethyl-2-((undec-10-enoyloxy)methyl)propane-1,3-diyl as a yellow
oil; IR (flim) 3469, 3076, 2926, 2855, 1745, 1640, 1466, 1416,
1389, 1355, 1235, 1157, 1116, 994, 909, 724 cm.sup.-1; .sup.1H NMR
(CDCl.sub.3): .delta.=5.86-5.72 (m, 41-1), 5.01-4.89 (m, 8H), 4.10
(s, 8H, CCH.sub.2O), 2.31-2.26 (m, 8H), 2.06-1.99 (m, 8H),
1.63-1.53 (m, 8H), 1.42-1.22 (m, 40H); .sup.13C NMR (CDCl.sub.3):
.delta.=173.1, 139.0, 114.1, 62.1, 41.83, 34.0, 33.7, 29.2, 29.1,
29.0, 28.9, 28.8, 24.8; MS-ESI m/z 801.8 (M+H).sup.+. Anal. Caled.
for C.sub.49H.sub.84O.sub.8: C, 73.46; H, 10.57. Found: C, 73.39;
H, 10.65.
Example 8
Preparation of the diester of biphenol A and 10-undecenoic acid
[0115] 2,2-diallybisphenol A (1.577 g, 5.11 mmol) and undecenoic
acid chloride (3.11 g, 15.34 mmol, 3 equiv.) were combined together
and the mixture was heated at 60.degree. C. for 16 hours. The
mixture was taken up in ether (50 ml) and washed with sodium
hydrogen carbonate (saturated aqueous solution) (3.times.50 ml)
then washed with brine (2.times.40 ml), dried over anhydrous
magnesium sulfate, filtered and reduced under partial pressure. The
crude material was purified by flash chromatography (ethyl
acetate/hexane 5/95) to give 3.11 g (95%) of the product as a pale
yellow oil; .sup.1H NMR (CDCl.sub.3): .delta.=7.09-7.04 (m, 4H),
6.92-6,90 (m, 2H), 5.90-5.77 (m, 4H), 5.04-4.92 (m, 8H), 6.50 (d,
4H, J=6.3 Hz), 2.54 (t, 4H, J=7.5 Hz), 2.08-2.01 (m, 4H), 1.77-1.70
(m), 1.64 (s, 6H), 1.43-1.32 (bs, 24H); .sup.13C NMR (CDCl.sub.3):
.delta.=172.8, 148.3, 147.1, 139.4, 136.3, 131.2, 128.9, 126.2,
121.9, 116.7, 114.4, 42.7, 35.1, 34.6, 34.0, 31.2, 29.5, 29.4,
29.3, 29.2, 29.1, 25.2; MS-ESI m/z (M+H).sup.+. Anal. Calcd. for
C.sub.43H.sub.60O.sub.4: C, 80.58; H, 9.44. Found: C, 78.81; H,
9.30.
Example 9
Cross-Linking of the butenolysis Product of Canola Oil to Give a
Film
[0116] Simple alkenes were removed from the butenolysis product of
canola oil (e.g. the product derived from Stage 1 of Example 4) by
vacuum distillation leaving a pale yellow oil. A sample of this oil
(0.46 g) was mixed with titanium dioxide (0.29 g) and ground to a
homogeneous mixture. This mixture was placed on a microscope slide
and a solution of Hoveyda-Grubbs Second Generation Catalyst (15 mg)
in dichloromethane (10 .mu.L) added and mixed thoroughly. The
mixture was spread to cover an area of 40.times.60 mm. After 1 hour
the film was found to have set to a solid film and have lost 0.025
g in mass. The film was found to be insoluble in the following
solvents: water; methanol; acetone; ethyl acetate; hexane;
toluene.
Example 10
Cross-Linking of an alkyd Resin Based on 9-undecenoic acid to Give
a Film
[0117] A sample of the product of Example 5 (1.0 g) was ground to a
homogeneous mixture with titanium dioxide (0.63 g) and toluene 0.5
mL. Hoveyda-Grubbs Second Generation Catalyst (15 mg) was mixed
thoroughly into the mixture, which was then painted onto a
microscope slide. After 10 minutes the film had set to give a
glossy surface. This film which was initially slightly soft, became
progressively harder over the next 12 hours to finally give a hard
tough film which adhered well to the glass. The film was found to
be insoluble in the following solvents: water; methanol; acetone;
ethyl acetate; hexane; toluene.
[0118] Colour Comparison
[0119] A film derived from the experimental white pigmented paint
was compared to a film derived from a commercially available white
pigmented alkyd paint (Dulux High Gloss Enamel). Films of the
experimental sample and commercial product were cast onto a sealed
panel using a #40 wire drawdown bar and the films dried fully over
48 hours. The colour difference between experimental and commercial
films was compared to the same reference white tile and the colour
difference coordinates calculated using a CIE1976 colour system.
Aging of the samples was then accelerated by taking the same panel
and taping it to the inside of a metal can having a close fitting
lid into which 5 ml of a 10% solution of ammonium hydroxide was
placed to saturate the atmosphere in the can. The panel was exposed
to these conditions for 48 hours.
[0120] Results:
TABLE-US-00002 Delta L Delta a Delta b Example 10 Before ammonia
exposure -0.70 0.03 0.47 After ammonia exposure -0.35 -0.25 1.33
Commercial Before ammonia exposure 0.10 -0.69 1.77 sample After
ammonia exposure -2.69 -0.42 12.74 (comparative)
[0121] The substantial difference in yellowness (+1.30) between the
experimental sample and the comparative sample prior to being
exposed to ammonia was clearly evident by eye. The effect of
ammonia exposure is a test well known as correlating with the
tendency of conventional enamels to yellow over time. After ammonia
exposure, the comparative sample showed significantly more
yellowing (+11.41). Due to the absence of autoxidation in the film
derived from the experimental sample, these results are expected to
reflect the difference that would be attained through natural
exposure over time. In other words, the crosslinked film in
accordance with the invention is expected to undergo little if no
yellowing over time.
Example 11
Cross-Linking of
2-ethyl-2-((undee-10-enoyloxy)methyl)propane-1,3-diyl
diundec-10-enoate to Give a Film
[0122] First Generation Grubbs Catalyst (10 mg) was dissolved in a
minimum volume of dichloromethane and mixed with
2-ethyl-2-((undec-10-enoyloxy)methyl)propane-1,3-diyl
diundec-10-enoate (0.80 g). The mixture was spread onto a
petridish. After 17 hours the mixture had become a hard and rubbery
film.
[0123] Throughout this specification and the claims which follow,
unless the context requires otherwise, the word "comprise", and
variations such as "comprises" and "comprising", will be understood
to imply the inclusion of a stated integer or step or group of
integers or steps but not the exclusion of any other integer or
step or group of integers or steps.
[0124] The reference in this specification to any prior publication
(or information derived from it), or to any matter which is known,
is not, and should not be taken as an acknowledgment or admission
or any form of suggestion that that prior publication (or
information derived from it) or known matter forms part of the
common general knowledge in the field of endeavour to which this
specification relates.
* * * * *