Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02219693 1997-10-30
Mo~597
MD-95-77-PU
DELAYED ACTION CATALYSTS FOR ALIPHATIC ISOCYANATES
BACKGROUND OF THE INVENTION
This invention relates to an improved catalyst system suitable for
catalyzing (cyclo)aliphatic isocyanate based polyurethane reactions. This
catalyst system comprises one or more organic tin carboxylates and one
or more chelating polyamines.
The production of polyurethane moldings via the reaction injection
10 molding (i.e. RIM) technique is well known and described in, for example,
U.S. Patent 4,218,543. The RIM process involves a technique of filling
the mold by which highly reactive, liquid starting components are injected
into the mold within a very short time by means of a high output, high
pressure dosing apparatus after they have been mixed in so-called
15 "positively controlled mixing heads".
In the production of polyurethane moldings via the RIM process,
the reaction mixture generally comprises an A-side based on
polyisocyanates and a B-side based on organic compounds containing
isocyanate-reactive hydrogen atoms, in addition to suitable chain
20 extenders, catalysts, blowing agents, and other additives. The
polyisocyanates which are suitable for a commercial RIM process are the
aromatic isocyanates such as, for example, diphenylmethane-4,4'-
diisocyanate (i.e. MDI).
Various patents such as, for example, U.S. Patent 4,937,366,
25 broadly disclose cycloaliphatic isocyanates, including methylenebis-
(cyclohexylisocyanate), in a long list of isocyanates which are said to be
suitable for use in a RIM process. However, very few of the patents
which disclose that cycloaliphatic isocyanates are suitable for use in a
RIM process have any working examples wherein a cycloaliphatic
30 isocyanate is used. The RIM examples of U.S. Pat~nt 4,937,366 are all
based on a prepolymer of an aromatic isocyanate.
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High productivity commercial RIM processes require a 30 second
demold time, and prefer mold temperatures less than about 80~C for
worker safety and energy efficiency. These are briefly described in U.S.
Patent 4,937,366. The RIM examples of this reference have a mold
5 temperature of 65~C and a demold time of 35 seconds.
U.S. Patent 4,772,639 describes a process for the production of
polyurethane moldings reacting organic polyisocyanates with organic
compounds containing isocyanate-reactive hydrogen atoms in the
presence of catalysts and auxiliary agents inside a closed mold. The
10 isocyanate component is based on (a1) mixtures of (i) 1-isocyanate-
3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), and (ii)
polyisocyanates containing isocyanurate groups prepared by the
trimerization of a portion of the isocyanate groups of 1,6-diisocyanato-
hexane, or (a2) (i) IPDI and (iii) polyisocyanates containing isocyanurate
15 groups prepared by the trimerization of a portion of the isocyanate
groups of a mixture of 1,6-diisocyanatohexane and IPDI. These reaction
mixtures are broadly disclosed as being suitable for RIM processing. The
reference also requires unusually long demold times, i.e. from 3 to 10
minutes. These demold times are not commercially acceptable for high
20 speed RIM production.
U.S. Patent 4,642,320 discloses a process for the preparation of a
molded polymer comprising reacting inside a closed mold a reaction
mixture comprising (a) an active hydrogen containing material comprising
a primary or secondary amine terminated polyether having an average
25 equivalent weight of at least 500, (b) at least one chain extender, and (c)
a (cyclo)-aliphatic polyisocyanate, polyisothiocyanate, or mixture thereof,
wherein the NCX index is from about 0.6 to 1.5. This process requires
that component (a) have at least 25%, and preferably 50% of its active
hydrogen atoms present in the form of amine hydrogens. All of the
30 examples disclose a system based on a HDI prepolymer with amine
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terminated polyethers and diethyltoluene diamine at high mold
temperatures and long demold times. Although the rerelence discloses
(cyclo)aliphatic isocyanates are suitable for this process, the mold
temperatures are higher than normal, i.e. at least 90~C, and the demold
5 times range from about 1 to 5 minutes.
U.S. Patent 4,764,543 discloses aliphatic RIM systems with short
demold times (~10 seconds) and low mold temperatures (~70~C) that use
very fast reacting aliphatic polyamines. This patent is restricted to total
polyurea systems based on chain extenders which are cycloaliphatic
10 diamines and polyethers which are amine-terminated polyethers, with an
aliphatically bound polyisocyanate.
RIM systems are also disclosed in U.S. Patent 4,269,945. These
systems are based on compositions comprising a polyisocyanate, a
hydroxyl-containing polyol, and a specific chain extender. The specific
15 chain extender comprises (1) at least one component selected from the
group consisting of (a) a hydroxyl-containing material which is essentially
free of aliphatic amine hydrogen atoms, and (b) aromatic amine-
containing materials containing at least two aromatic amine hydrogen
atoms and are essentially free of aliphatic amine hydrogen atoms; and
20 (2) at least one aliphatic amine-containing material having at least one
primary amine group and an average aliphatic amine hydrogen
functionality of from about 2 to 16. Both aromatic polyisocyanates and
(cyclo)aliphatic polyisocyanates are disclosed as being suitable for this
process. All of the working examples in this patent use aromatic
25 isocyanates that may be polymeric in nature. Demold times of 60
seconds are disclosed for the examples even though comparatively faster
reacting aromatic isocyanates are used.
U.S. Patent 5,260,346 also discloses reaction systems for
preparing elastomers via the RIM process. These systems require an
30 allophanate modified polyisocyanate, a hydroxyl group containing polyol,
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and an aromatic polyamine having at least one of the positions ortho to
the amine substituted with a lower alkyl substituent.
U.S. Patent 5,502,147, which is commonly assigned, describes
(cyclo)aliphatic isocyanate based RIM systems. These (cyclo)aliphatic
isocyanates have a viscosity of less than 20,000 mPa s at 25~C, an NCO
functionality of 2.3 to 4.0, and are modified by isocyanurate groups,
biuret groups, urethane groups, a!lophanate groups, carbodiimide groups,
oxadiazine-trione groups, uretdione group.s, and blends thereof. All of the
working examples of this application use hexamethylene diisocyanate
10 which is modified by one of the 2bove groups.
U. S. Patent 5,502,150, which is commonly assigned, discloses a
RIM process which uses a hexamethyiene diisocyanate prepolymer
having a functionality of less than 2.3, an NCO content of 5 to 25%, and
a monomer content of less than 2% by weight. This prepolymer is
15 reacted with a high molecular weight isocyanate-reactive compound, a
chain extender selected from diols and aminoalcohols, and a hydroxyl-
based crosslinking compcund containing no more than one (1) aliphatic
amine hydrogen atom. The claims reguire a catalyst composition
comprising 1) at least one catalyst selected from the group consisting of
20 metal carboxylates, metal halides, ammonium carboxylates and mixtures
thereof, and, optionally, 2) one or more tin-sulfur catalysts, and,
optionally, 3) one or more tertiary amine catalysts.
In all of the working examples of U.S. Patent 5,502,150 in which a
polyurethane is formed, dimethyltin dilaurate (Formez UL-28) is the only
25 catalyst used. One of the examples, however, uses seven (7) parts of a
tetrafunctional hydroxyl based crosslinker prepared by propoxylating
ethylene diamine and having an OH number of about 630. Although this
particular compound is chemically similar to the chelating polyamines
required by the present invention, the isocyanate is a linear HDI
30 prepolymer which is different than the polyisocyanates required by the
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present invention. Long gel times and good flow are observed for linear
and low functionality (i.e. < 2.3) polyisocyanates. For these lower
functionality systems, one generally uses crosslinkers to quickly build
molecular weight for good green strength and properties. For a high
5 functional (i.e.> 2.3) polyisocyanate, one would refrain from using a
crosslinker since good green strength is usually observed. It would
certainly not be expected that a prolonged gel time and viscosity build up
would result by the addition of a crosslinker.
Copending Application Serial No. 08/744,037 filed November 5,
10 1996, which is a Continuation-in-part of Application Serial No. 08/484,402
filed June 7, 1995 (now abandoned), which is commonly assigned,
discloses a method of producing window gaskets of polyurethane/urea
compositions. These polyurethane/urea compositions comprise a
(cyclo)aliphatic polyisocyanate having a viscosity of less than 25,000
15 mPa s at 25~C and an average NCO functionality of about 2.0 to 4.0,
with an isocyanate-reactive composition comprising a high molecular
weight isocyanate-reactive component and a low molecular weight chain
extender, in the presence of a catalyst wherein the reactive components
are selected such that the final polyurethane/urea composition has a
20 crosslink density of at least 0.3 moles/kg.
Tertiary amines are known to catalyze aromatic isocyanate/polyol
systems synergistically with organo-tin compounds. Thus, it was
surprising to find that a combination of organo-tin and chelating
polyamines resulted in delayed reactivity when using an (cyclo)aliphatic
25 isocyanate instead of an aromatic isocyanate. This catalyst combination
prolongs viscosity build-up and gel time without compromising the green
strength of the molded polyurethane. Advantages of the presently
claimed invention include improved flow in highly catalyzed RIM systems
based on higher functional aliphatic and cycloaliphatic polyisocyanates
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which leads to more complete mold fill-out and better surface quality.
Improved flow also leads to more isotropic properties, particularly, flexural
modulus.
SUMMARY OF THE INVENTION
This invention relates to delayed action catalyst systems for
(cyclo)aliphatic polyisocyanate based polyurethane reactions. These
delayed action catalyst systems comprise one or more organic tin
carboxylates and one or more chelating polyamines.
More specifically, this invention relates to a process for the
10 production of polyurethane molded articles by the reaction injection
molding (RIM) process comprising injecting a reaction mixture comprising
a (cyclo)aliphatic polyisocyanate component having a NCO functionality
of 2.3 to 4.0 and an isocyanate-reactive component in a closed mold,
allowing the reaction mixture to Fully react and removing the molded
15 articles from the mold, wherein the reaction bet~een the (cyclo)aliphatic
polyisocyanate component and the isocyanate-reactive component
occurs in the presence of a catalyst composition comprising:
a) from 0.1 to 10% by weight, based on the total weight of the
isocyanate-reactive component and the catalyst
composition, of one or more organic tin carboxylates or tin
halides,
and
b) from 0.1 to 6.0% by weight, based on the total weight of the
isocyanate-reactive component and the catalyst
composition, of one or more chelating polyamines.
The present invention also relates to an isocyanate-reactive blend
comprising
1 ) at least one isocyanate-reactive component,
and
2) a catalyst composition comprising:
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a) from 0.1 to 10% by weight, based on the total weight
of the isocyanate-reactive component and the
catalyst composition, of one or more organic tin
carboxylates or tin halides,
and
b) from 0.1 to 6.0% by weight, based on the total weight
of the isocyanate-reactive component and the
catalyst composition, of one or more chelating
polyamines.
Suitable chelating poiyamines include those corresponding to the
general formula:
R1 R2
\ N--R3--N/ (I)
R4/ \R5
wherein:
R3: represents the group -(-CH2CH20CH2CH2-)-, a branched or
non-branched alkylene group containing from 2 to 10
carbon atoms, preferably 2 to 6 carbon atoms, most
preferably 2 to 3 carbon atoms, or corresponds to the
formula:
2m[ l 2 ~
wherein:
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z: represents an integer of from 0 to 3,
m: represents an integer of from 2 to 6,
n: represents an integer of from 2 to 6,
and
R6: has the meaning setforth below;
and
R', R2, R4, R5 and R6: may be the same or different, and are
selected from the group consisting of:
1 ) hydrogen;
2) an alkyl group containing from 1 to 18 carbon atoms;
3) a hydroxyalkyl group corresponding to the formula:
~CH2 CH O~H
R7 P
wherein:
p: represents an integer of from 1 to 6,
R7 represents hydrogen or CH3;
4) at ieast one heterocyclic ring formed when any two R
groups selected from the group consisting of R', R2, R4, R5
and R6 are joined together in a ring structure, thereby
forming an alkylene group, an oxaalkylene group, or an
azaalkylene group;
and
5) a group corresponding to the formula:
(cH2~N\
R9
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Mo4597 9
wherein:
q: represents an integer of from 2 to 6,
and
R8 and R9 may be the same or different, and are selected
from the group consisting of:
i) hydrogen;
ii) an alkyl group containing from 1 to 18 carbon atoms;
preFerably a methyl group,
iii) a hydroxyalkyl group corresponding to the formula:
~CH2 CH O ) 11
~10
1 0 wherein:
s: represents an integer of from 1 to 6,
and
R'~: represents hydrogen or methyl;
and
iv) a heterocyclic ring formed by R8 and R9 joining
together in a ring structure to form an alkylene group,
an oxaalkylene group or an a~aalkylene group.
DETAILED DESCRIPTION OF THE INVFNTION
The catalyst composition required by the present invention
comprises:
a) from 0.1 to 10% by weight, based on the total weight of the
isocyanate-reactive component and the catalyst
composition, of one or more organic tin carboxylates or
organic tin halides,
and
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b) from 0.1 to 6.0% by weight, based on the total weight of the
isocyanate-reactive component and the catalyst
composition, of one or more chelating polyamines.
Suitable tin carboxylates and tin halides for the catalyst system
5 required by the present invention include, for example, dibutyltin
dilaurate, dimethyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate,
dioctyltin dilaurate, dimethyltin maleate, dibutyltin maleate, dioctyltin
maleate, dimethyltin dichloride, dibutyltin dichloride, etc.
Suitable chelating polyamines include those corresponding to the
10 general formula (I):
R1
\ N--R3--N/ ~)
R4/ \R5
wherein:
R3: represents the group -(-CH2CH2OCH2CH2-)-, a branched or
non-branched alkylene group containing from 2 to 10
carbon atoms, preferably from 2 to 6 carbon atoms, most
preferably 2 to 3 carbon atoms, or corresponds to the
formula:
2m[ 16
wherein:
z: represents an integer of from 0 to 3, preferably 0 to 2,
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Mo4597
m: represents an integer of from 2 to 6, preferably 2 to 3,
n: represents an integer of from 2 to 6, preferably 2 to 3;
and
R6: has the meaning set forth below;
and
R1, R2, R4, R5 and R6: may be the same or different, and each
represents
1 ) hydrogen;
2) an alkyl group containing from 1 to 18 carbon atoms,
preferably 1 carbon atom;
3) a hydroxyalkyl group corresponding to the formula:
~ H2 ~CH--O~H
wherein:
p: represents an integer of from 1 to 6, preferably 1 to 3, and
R7: represents hydrogen or CH3;
4) at least one heterocyclic ring formed when any two R
groups selected from the group consisting of: R', R2, R4, R5
and R6 are joined together in a ring structure to form an
alkylene group, an oxaalkylene group or an azaalkylene
group;
and
5) a group corresponding to the formula:
(CH2)q N
R9
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Mo4597 -1 2-
wherein:
q: represents an integer of from 2 to 6,
and
R8 and R9: may be the same or different, and are selected from
the group consisting of:
i) hydrogen;
ii) an alkyl group containing from 1 to 18 carbon atoms,
preferably a methyl group;
iii) a hydroxylalkyl group corresponding to the formula:
~CHz--Cl I ~ )s I I
~10
1 0 wherein:
s: represents an integer of from 1 to 6, preferably 1 to 3,
and
R'~: represent hydrogen or methyl;
and
iv) a heterocyclic ring formed by R8 and R9 joining together in a
ring structure thereby forming an alkylene group, an
ozaalkylene group or an azaalkylene group.
In the present invention, it is preferred that these chelating
polyamines have a molecular weight of from about 100 to about 2,000,
and more preferably of from about 100 to about 500. It is also preferred
that these chelating polyamines contain no more than 7 nitrogen atoms
per molecule, more preferably no more than 5 nitrogen atoms per
molecule and most prsferably no more than 4 nitrogen atoms per
molecule.
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ln formula (I) above, wherein a heterocyclic ring is formed by two
of the R groups combining together, such as, for example, R' and R4
combining together, the chelating polyamine corresponds to the following
general structure (Il):
(Il)
(CH2)B Rs
wherein:
A and B: may be the same or different and each represents 1
or 2, preferably 2,
R~: is as defined above in general formula (I),
R2 and R5: are as defined above in general formula (I),
1 0 and
X: represents 0, CH2, or N-R1',
wherein:
R": is selected from the group consisting of:
i) hydrogen;
ii) an alkyl group containing from 1 to 18 carbon atoms, and
preferably a methyl group;
and
iii) a hydroxyalkyl group corresponding to the formula:
R~
whereln:
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t: represents an integer of from 1 to 6, preferably 1 to 3,
and
R'2: represents hydrogen or a methyl group.
A chelating polyamine having a heterocyclic ring structure similar
5 to structure (Il) above is also formed, for example, when R2 and R5 join
together in a ring structure to form, for example, an alkylene group, an
oxaalkylene group or an azaalkylene group, and, simultaneously, R' and
R4 do not join in a ring structure. Of course, two heterocyclic rings may
be present in formula (Il) if, for example, R' and R4 join together in ring
10 structure, and R2 and R5 join together in another ring structure.
One suitable example of a chelating polyamine corresponding to
structure (Il) is, for example, N,N-dirnethylaminoethyl morpholine,
commercially available as Dabco XDM from Air Products. This polyamine
has the following structure:
CH--CH
(cH3)2NcH2cH2 N\ 2 ~O
CH2--CH2
Another example of a chelating polyamine corresponding to
general structure (Il) above is, for example, N-methyl-N'-(2-
dimethylamino)ethyl-piperazine), which is commercially available under
the tradename Toyocat NP from Toyo Soda Company. This polyamine
has the following structure:
H3C~ /CH2--CH2~
jN--CH--CH--N N--CH3
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ln formula (I) above, it is, for course, possible that two heterocyclic
rings are present. This embodiment of the invention occurs when, for
example, two pairs of R groups each join in a ring structure so that each
pair forms an alkylene group, an oxaalkylene group or an azaalkylene
5 group. These chelating polyamines correspond to the following general
structure (lla):
Y/ N--R3--N/ E\Z (,la)
\ (CH2)D/ \ (CH2)F
wherein:
C, D, E and F: may be the same of different and each
represents 1 or 2, preferably 2,
R3: is as defined above in general formula (I),
and
Y and Z: may be the same or different, and each represents
0, CH2, or N-R'3,
wherein:
R'3: is selected from the group consisting of:
i) hydrogen,
ii) an alkyl group containing from 1 to 18 carbon atoms,
and preferably a methyl group,
and
iii) a hydroxyalkyl group corresponding to the formula:
~CH2--ICH ~)u
R'4
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wherein:
u: represents an integer of from 1 to 6, preferably 1 to
3,
and
R'4: represents hydrogen or a methyl group.
An example of a chelating polyamine which corresponds to
general structure (lla) above wherein one heterocyclic ring is formed by
R' and R4 joining together in a ring structure as an oxaalkylene group,
and, simultaneously, another heterocyclic ring is formed by R2 and R5
10 joining together in a ring structure as an oxaalkylene group, is N,N-
dimorpholinodiethyl ether. This chelating polyamine is commercially
available under the name Jeffcat DMDEE, from Huntsman Corp. The
structure of this polyamine is as follows:
O~ 2 2--N--CH CH--o--CH CH2--N/ ' o
~CH--CH2/ CH--CH
In formula (I) above, wherein a heterocyclic ring is formed by
15 combining two of the R groups together, such as, for example, when R'
and R2 together form another R3group, the chelating polyamine
corresponds to the follcwing general structure (Ill):
R3
R4--N ~Rs
\ R3
wherein:
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R3 is defined as above in general formula (1), preferably a
branched or unbranched alkylene group, and most
preferably a CH2-CH2 group,
R4 and R5 are as defined above in general formula (1).
A suitable compound which corresponds to general formula (111)
above is, for example, N,N-dimethylpiperazine. This chelating polyamine
is commercially available under the name Jeffcat DMP, from Huntsman
Corp. This particular polyamine has the following formula:
H3CN NCH3
A suitable compound having a structure similar to structure (111)
above is, for example, N-methyl-N'-2-hydroxyethylpiperazine. This
chelating polyamine is commercially available under the name Toyocat-
HP, from Toyo Soda Company. This particular polyamine has the
following formula:
/CH--CH
H C--N N--CH2CH2--OH
CH--CH2/
A compound having a structure identical to structure (111) above
which contains a heterocyclic ring is also formed when R4 and Rs
combine together form another R3 group, and R' and R2 do not enter into
a ring structure.
In formula (111) above, when both R3 groups are ethylene groups,
and, simultaneo~usly, R4 and R5 are also joined together in a ring
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structure to form a third ethylene group, a heterobicyclic ring results. This
chelating polyamine corresponds to the following general structure (IV):
N N (1\/)
The chelating polyamine represented by structure (IV) is 1,4-diaza[2.2.2]-
bicyclooctane, commercially available from Air Products as either Dabco
5 Crystalline (100% solids) or as Dabco 33LV (33% solids).
Some examples of suitable chelating polyamines include
compounds such as tetra-substituted ethylene diamines such as, for
example, propoxylated ethylane diamine having an OH number of about
630, N,N'-dimethyl aminoethyl N-methyl ethanolamine which is
10 commercially available as Dabco T from Air Products, 1,4-
diaza[2.2.2]bicyclooctane commercially available from Air Products,
penta-substituted diethylene triamines such as, for example, pentamethyl
diethylene triamine (commercially available as Polycat 5 from Air
Products), Polycat 77, pentamethyl dipropylene triamine, Polycat 17,
15 trimethylaminopropyl ethanolamir,e, Polycat 9, tris(dimethyl
aminopropyl)amine, etc.
These catalysts and structures identified above are not intended to
be limiting of the possible chel2ting polyamine catalysts which are within
the scope of the present invention. ~ather, these are only to provide
20 some examples of suitable chelating polyamines for the present
invention.
In accordance with the present invention, a suitable (cyclo)aliphatic
polyisocyanate somponent may represent either an aliphati
polyisocyanate or a cycloaliphatic polyisocyanate. Suitable
25 (cyclo)aliphatic polyisocyanates for the present invention having an NCO
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Mo4597 -19-
functionality of 2.3 to 4.0, and preferabiy a viscosity of less than about
20,000 mPa s at 25~C. It is preferred that the polyisocyanate component
of the present invention contain at least one functional group which is
selected from the group consisting of
a1) isocyanurate groups,
a2) biuret groups,
a3) uretdione groups,
a4) urethane groups,
a5) allophanate groups,
a6) a combination of isocyanurate and allophanate groups,
a7) carbodiimide groups and/or uretone imines,
a8) oxadiazinetrione groups, and
a9) blends thereof.
Suitable polyisocyanate components and adducts for the present
invention include, for example, organic aliphatic diisocyanates and
organic cycloaliphatic diisocyanates such as 1,4-tetramethylene
diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-
hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate,
cyclohexane-1,3- and -1,4-diisocyanate, 1-isocyanato-2-isocyanatomethyl
cyclopentane, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl-cyclo-
hexane (isophorone diisocyanate or IPDI), bis-(4-isocyanatocyclohexyl)-
methane, 2,4'-dicyclohexylmethane diisocyanate, 1,3- and 1,4-bis-
(isocyanatomethyl)-cyclohexane, bis-(4-isocyanato-3-methylcyclohexyl)-
methane, a,a,a',a'-tetramethyl-1,3- and/or -1,4-xylylene diisocyanate, 1-
isocyanato-1 -methyl-4(3)-isocyanatomethyl cyclohexane, 2,4- and/or ,6-
hexahydrotoluylene diisocyanate, and mixtures thereof. It is preferred
that the isocyanate be based on an aliphatic diisocyanate.
Suitable polyisocyanate adducts containing biuret groups include
polyisocyanates such as those described, for example, in U.S. Patents
3,124,605, 3,358,010, 3,644,490, 3,862,973, 3 906,126, 3,903,127,
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4,051,165, 4,147,714, and 4,220,749, the disclosures of which are herein
incorporated by reference. As set forth in these patents, these biuret
group-containing polyisocyanates may be prepared by using co-reactants
such as water, tertiary alcohols, primary and secondary monoamines,
5 and primary and/or secondary diamines. These polyisocyanates
preferably have an NCO content of 18 to 22% by weight and an average
NCO functionality of 2.3 to 4.0, preferably of 3 to 3.5.
Suitable polyisocyanates containing isocyanurate groups include
compounds such as those described, for example, in U.S. Patent
10 4,288,586 and 4,324,879, the disclosures of which are herein
incorporated by reference; European Patents 3,765, 10,589 and 47,452,
the disclosures of which are herein incorporated by reference; and
German Offenlegungsschriften 2,616,416, herein incorporated by
reference. The isocyanato-isocyanurates generally have an average
NCO functionality of 2.3 to 4.0, preferably of 3 to 3.5, and an NCO
content of 5 to 30%, preferably 10 to 25% and most preferably 15 to 25%
by weight.
Uretdione diisocyanates may be prepared by oligomerizing a
portion of the isocyanate groups of a diisocyanate in the presence of a
trialkyl phosphine catalyst, and may bs used in admixture with other
aliphatic and/or cycloaliphatic polyisocyanates, particularly the
isocyanurate group-containing polyisocyanates described hereinabove.
Urethane group-containing polyisocyanates which may be
prepared in accordance with the process disclosed in U.S. Patent No.
31183,112, herein incorporated by reference, by reacting excess
quantities of polyisocyanates, preferably diisocyanates, with low
molecular weight glycols and polyols having molecular weights of less
than 400, such as trimethylol propane, glycerine, 1,2-dihydroxy propane
and mixtures thereof.
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Allophanate group-containing polyisocyanates include, for
example, those prepared according to the processes disclosed in U.S.
Patent Nos. 3,769,318, 4,160,080 and 4,177,342, the disclosures of
which are herein incorporated by reference.
Isocyanurate and allophanate group-containing polyisocyanates
include, for example, those which may be prepared in accordance with
the processes set forth in U.S. Patents 5,124,427, 5,208,334 and
5,235,018; the disclosures of which are herein incorporated by reference.
These polyisocyanates containing isocyanurate and allophanate groups
10 preferably have an NCO content of 16 to 22% by weight, most preferably
of 18 to 21% by weight.
Suitable carbodiimide group-containing and uretone imine group-
containing polyisocyanates for the present invention include, for example,
those which may be prepared by oligomerizing di- or polyisocyanates in
15 the presence of known carbodiimidization catalysts such as described in,
for example, German Patentschriften 1,092,007, herein incorporated by
reference, U.S. Patent 3,152,162, herein incorporated by reference, and
German Offenlegungschriften 2,504,400, 2,537,685 and 2,552,350, the
disclosures of which are herein incorporated by reference.
It is also possible to use polyisocyanates containing oxadiazine-
trione groups and containing the reaction product of two moles of a
diisocyanate and one mole of carbon dioxide.
Preferred polyisocyanate adducts are the polyisocyanates
containing isocyanurate groups a1), biuret groups a2), or polyisocyanates
25 containing both isocyanurate and allophanate groups a6). Isocyanurate
group-containing polyisocyanates suitable for the present invention
generally have an average NCO functionality of about 2.3 to 4.0 and a
viscosity of less than about 20,000 mPa s at 25~C. The biuret group-
containing polyisocyanates generally have an average NCO functionality
30 of about 2.3 to 4.0 and a viscosity of less than about 20,000 mPa s at
CA 02219693 1997-10-30
Mo4597 -22-
25~C. Polyisocyanates containing isocyanurate and allophanate groups
generally have an average NCO functionality of about 2.3 to 4.0 and a
viscosity of less than about 20,000 mPa s at 25~C.
It is more preferred to use isocyanurate group-containing
5 polyisocyanates as component a1) which are prepared, for example, by
trimerizing a portion of the isocyanate groups of 1,6-hexamethylene
diisocyanate; containing tris-(6-isocyanatohexyl)-isocyanurate and higher
homologs thereof; and having an NCO content of about 20-23% by
weight, a monomeric diisocyanate content of <2%, a viscosity at 25~C of
10 less than 10,000 mPa s and an average isocyanate (i.e. NCO)
functionality of about 3 to 3.5. Suitable compounds include isocyanurate
group-containing polyisocyanates such as those described, for example,
in U.S. Patents 4,288,586 and 4,324,879, the disclosures of which are
herein incorporated by reference. Low monomer content polyisocyanates
15 such as these significantly decrease health concerns and risks
associated with handling polyisocyanates.
The more preferred polyisocyanates to be used as component a2)
include, for example, tris-(6-isocyanatohexyl)-biuret or mixtures thereof
with its higher homologs. These biuret group-containing polyisocyanates
20 generally have a NCO content of about 18 to 25% by weight and an
average NCO functionality of about 2.3 to 4Ø Suitable biuret group-
containing polyisocyanates include polyisocyanates such as those
described, for example, in U.S. Patent 3,903,127, herein incorporated by
reference. As mentioned hereinabove, low monomer content polyiso-
25 cyanates such as these significantly decrease health concerns and risksassociated with handling polyisocyanates.
Another more preferred group of polyisocyanate adduct includes
the polyisocyanates containing isocyanurate and allophanate groups that
are based on 1,6-hexamethylene diisocyanate. Suitable such
30 compounds generally have an I~ICO content of from 16 to 22 % by
CA 02219693 1997-10-30
Mo4597 -23-
weight, and a viscosity of less than about 3000 mPa s at 25~C. Some
examples of suitable isocyanates include, for example, those compounds
described, for example, in U.S. Patents 5,124,427, 5,208,334, and
5,235,018, the disclosures of which are herein incorporated by reference.
These polyisocyanates also contain low quantities of monomeric
isocyanates.
A most preferred isocyanurate group-containing polyisocyanate to
be used as component a1) can be prepared from 1,6-hexamethylene
diisocyanate and having an isocyanate content of about 21.6%, a content
10 of monomeric diisocyanate of <0.2%, and a viscosity at 25~C of about
3000 mPa s.
A most preferred biuret group-containing polyisocyanate to be
used as component a2) of the invention can be prepared from 1,6-hexa-
methylene diisocyanate and having an isocyanate content of about 23%,
15 a content of monomeric diisocyanate of <0.7% and a viscosity at 25~C of
about 1300-2200.
A most preferred polyisocyanate containing isocyanurate and
allophanate groups to be usPd 25 component a6) can be prepared from
1,6-hexamethylene diisocyanate and 1-butanol, and has an isocyanate
20 content of about 18 to 21 % by weight such as described, for example, in
U.S. Patent 5,124,427, herein incorporated by reference. This preferred
polyisocyanate component has an isocyanate content of about 18 to 21%
by weight, a viscosity at 25~C of less than about 1500 mPa s, and a
monomeric diisocyanate content of < 0.7%.
The aliphatic polyisocyanate component contains less than 10%
by weight of isophorone diisocyanate. As mentioned hereinabove, this
particular isocyanate tends to slow down the reactivity of the entire RIM
system. In addition, the aliphatic isocyanate component preferably
contains less than 2.5%, most preferably less than 1 %, by weight of
30 monomeric isocyanate.
CA 02219693 1997-10-30
Mo4597 -24-
Suitable isocyanate-reactive components B) to be used in the
process according to the invention include, for example, relatively high
molecular weight compounds which contain groups capable of reacting
with the NCO groups of the polyisocyanate component and/or relatively
5 low molecular weight compounds which contain groups capable of
reacting with the NCO groups of the polyisocyanate component.
Relatively high molecular weight compounds suitable for the
present invention which are isocyanate-reactive typically contain hydroxy
group, amine groups, or both, and an average functionality of from 1.0 to
10 4, preferably 1.5 to 3, and a number average molecular weight of about
500 to 10,000, preferably from about 2,000 to 6,000. Examples of
suitable compounds to be used as component b1 ) include the polyethers,
polyesters, polythioethers, polyacetals, polycarbonates, and amine
terminated polyethers containing from 1 to 4 isocyanate-reactive groups
15 of the type known for the production of polyurethanes.
The high molecular weight polyethars suitable for use in
accordance with the invention are known and may be obtained, for
example, by polymerizing tetrahydrofuran or epoxides such as, for
example, ethylene oxide, p!opylene oxide, butylene oxide, styrene oxide
20 or epichlorohydrin in the presence of suitable catalysts, such as, for
example, BF3 or KOH, or by chemica!ly adding these epoxides,
preferably ethylene oxide and propylene oxide, in admixture or
successively to components containing reactive hydrogen atoms such as
water, alcohols or amines. Examples of suitable alcohols and amines
25 include the low molecular weight chain extenders set forth hereinafter,
propylene glycol, glycerin, ethylene glycol, triethanolamine, water,
trimethylolpropane, bisphenol A, sucrose, aniline, ammonia, ethanolamine
and ethylene diamine. It is preferred to use polyethers which contain
substantial amounts of primary hydroxyl groups in terminal positions
CA 02219693 1997-10-30
Mo4597 -25-
(greater than 80% by weight, based on all of the terminal hydroxyl groups
present in the polyether).
Polyether polyols are preferably used as component b1) in the
invention. Preferred polyethers include, for example, those compounds
5 based on di- or tri-functional starters such as, for example, water,
ethylene glycol, propylene glycol, glycerin, trimethylolpropane, or
triethanolamine. These preferred compounds include copolymers of
ethylene oxide and propylene oxide with greater than 15% by weight of
the oxides being ethylene oxides.
Suitable examples of high molecular weight polyesters include, for
example, the reaction products of polyhydric, preferably dihydric alcohols
(optionally in the presence of trihydric alcohols), with polyvalent,
preferably divalent, carboxylic acids. Instead of using the free carboxylic
acids, it is also possible to use the corresponding polycarboxylic acid
anhydrides or corresponding polycarboxylic acid esters of lower alcohols
or mixtures thereof for producing the polyesters. The polycarboxylic
acids may be aliphatic, cycloaliphatic, aromatic, and/or heterocyclic and
may be unsaturated or substituted, for example, by halogen atoms. The
polycarboxylic acids and polyols used to prepare the polyesters are
known and described for example in U.S. Patents 4,098,731 and
3,726,952, herein incorporated by reference in their entirety. Suitable
polythioethers, polyacetals, polycarbonates and other polyhydroxyl
compounds are also disclosed in the above-identified U.S. Patents.
Finally, representatives of the many and varied compounds which may
be used in accordance with the invention may be found, for example, in
High Polymers, Volume XVI, "Polyurethanes, Chemistry and
Technology," by Saunders-Frisch, Interscience Publishers, New York,
London, Vol. l, 1962, pages 3242 and 44-54, and Volume ll, 1964,
pages 5-6 and 198-199; and in Kunststoff-~landbuch, Vol. Vll, Vieweg-
Hochtlen, Carl Hanser Verlag, Munich, 1966, pages 45-71.
CA 02219693 1997-10-30
Mo4597 -26-
ln another embodiment, the polyhydroxyl compound b1) may
additionally comprise: i) a dispersion of a polyurea and/or polyhydrazo-
dicarbonamide in a relatively high molecular weight organic compound
containing at least two hydroxyl groups, ii) a polymer polyol prepared by
5 polymerizing an ethylenically unsaturated monomer or monomers in a
relatively high molecular weight organic compound containing at least t\,vo
hydroxyl groups, or iii) blends thereof. It is possible to use these types of
polyols either alone, or in conjunction with the conventional polyethers
described hereinabove.
These types of polyols are known, and can be characterized as
hydroxyl containing compounds which contain high molecular weight
polyadducts, polycondensates, or polymers in finely dispersed or
dissolved form. Such polymers may be obtained by polyaddition
reactions (for example, reactions between polyisocyanates and
15 aminofunctional compounds) and polycondensation reactions (for
example, between formaldehyde and phenols and/or amines) in situ in
the hydroxyl group containing compound. Such processes are described
in, for example, German Auslegeschriften 1,168,075 and 1,260,142, the
disclosures of which are herein incorporated by reference, and in German
20 Offenlegungsschriften 2,324,134, 2,423,984, 2,512,385, 2,513,815,
2,550,796, 2,550,797, 2,550,833, 2,550,862, 2,633,293, and 2,639,254,
the disclosures of which are herein incorporated by reference. See also
U.S. Patents 3,325,421, 4,042,537, 4,089,835, 4,293,470, 4,296,213,
4,374,209, and 4,786,706, the disc!osures of which are herein
25 incorporated by reference. Polyols of this type are commercially
available from Bayer Corporation and Bayer AG. Also useful are the so-
called polymer polyols obtained by polymerizing one or more ethylenically
unsaturated monomers in a hydroxy group containing compound.
Polyols modified by vinyl polymers, of the type formed, for example, by
30 polymerizing styrene or acrylonitrile in the presence of polyether polyol
CA 02219693 1997-10-30
Mo4597 -27-
are also suitable, as are polybutadienes containing OH groups. Such
polymer polyols are described in U.S. Patents 3,383,351, 3,304,273,
3,523,093, 3,110,685, and RE 28,715 and 29,118, and German Patent
1,152,536, the disclosures of which are herein incorporated by reference.
5 Polymer polyols are commercially available from Bayer AG, BASF, and
Union Carbide.
The preferred PHD polyols include, for example, the polyurea of
toluene diisocyanate and hydrazine dispersed in polyether polyol, and the
preferred polymer polyols include, for example, those based on the
10 monomers styrene and acrylonitrile.
It is also possible that the high molecular weight isocyanate-
reactive component comprises a small quantity such as, for example, up
to about 50% by weight, based on the weight of the high molecular
weight isocyanate-reactive component, of the so-called amine terminated
15 polyethers (ATPEs). These may contain primary or secondary,
aromatically or aliphatically bound amino groups, wherein amino end
groups can also be attached to the polyether chain through urethane or
ester groups. These amine terminated polyethers can be prepared by
any of several methods known in the art. Suitable methods can be found
20 in, for example, Belgian Patent No. 634,741, U.S. Patent 3,155,728,
3,236,895, 3,654,370, 4,396,729, 4,433,067, 4,444,910 and 4,530,941,
German Patent 1,193,671, and French Patent Nos. 1,466,708 and
1,551,605. It is preferred, however, that the high molecular weight
isocyanate-reactive component ~oes not comprise any quantity of these
25 am ine term inated polyethers.
The isocyanate-reactive component B) may additionally comprise:
relatively low molecular weight compounds which contain groups capable
of reacting with the NCO groups of the polyisocyanate component. These
may be chain terminators, chain extenders, and/or crosslinkers, and may
30 contain hydroxyl groups, amine groups, or both. Suitable relatively low
CA 02219693 1997-10-30
Mo4597 -28-
molecular weight compounds generally have molecular weights of from
about 60 to less than 500, and contain from 1 to 8, preferably from 1 to
4 isocyanate-reactive groups. The OH:NH equivalent ratio of the low
molecularweightcomponentisfrom 1:1 toabout25:1, preferably3:1 to
5 18:1.
Suitable organic polyols to be used as relatively low molecular
weight components according to the invention include, for example, diols
and triols such as, for example, 2-methyl-1,3-propanediol, ethylene
glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4- and 2,3-butane-diol, 1,6-
10 hexanediol, 1,10-decanediol, diethylene glycol, triethylene glycol, tetra-
ethylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol,
cyclohexanedimethanol, and 2,2,4-trimethylpentane-1,3- diol. Preferred
diols include, for example, 1,4-butanediol, 1,3-butanediol, and 2-methyl-
1,3-propanediol.
Suitable aminoalcohols to be used as a relatively low molecular
weight component include, for example, monoisopropanolamine,
monoethanolamine, etc.
Suitable amine compounds to be used as a relatively low
molecular weight component according to the invention include organic
20 primary amines and secondary amines such as, for example, 2-methyl-
1,5-pentane diamine, ethylene diamine, 1,3-diamino-propane, 1,3-
diaminobutane, 1,4-diaminobutane, isophorone-diamine, diamino-
cyclohexane, hexamethylerlediamine, methyliminobis-(propyl-amine),
iminobis(propylamine), bis(aminopropyl)piperazine, aminoethyl piperazine,
25 bis-(p-aminocyclohexyl)-methane, mixtures thereof, and the like.
Other suitable amines include, for example,1,8-p-diamino-
menthane, bis(4-amino-3-methylcyclohexyl)methane, bis(4-amino-3,5-
dimethylcyclohexyl)methane, bis(4-amino-2,3,5-trimethylcyclohexyl)-
methane, 1,1-bis(4-aminocyclohexyl)propane, 2,2-(bis(4-aminocyclo-
30 hexyl)propane, 1,1-bis(4-aminocyclohexyl)ethane, 1,1-bis(4-aminocyclo-
CA 02219693 1997-10-30
Mo4597 -29-
hexyl)butane, 2,2-bis(4-am inocyclohexyl)butane, 1,1 -bis(4-am ino-3-
methylcyclohexyl)ethane, 2,2-bis(4-amino-3-methylcyclohexyl)propane,
1,1 -bis(4-amino-3,5-dimethylcyclohexyl)ethane, 2,2-bis(4-amino-3,5-
dimethylcyclohexyl)propane, 2,2-bis(4-amino-3,5-dimethylcyclohexyl)-
butane, 2,4-diaminodicyclohexylmethane, 4-aminocyclohexyl4-amino-3-
methylcyclohexylmethane, 4-amino-3,5-dimethylcyclohexyl-4-amino-3-
methylcyclohexylmethane, and 2-(4-aminocyclohexyl)-2-(4-amino-3-
methylcyclohexyl)methane.
It is also possible to use the so-called amine-terminated
10 polyethers having low molecular weights. Among the suitable amine
terminated polyethers include, for example, those containing primary or
secondary (preferably primary) aromatically or aliphatically (preferably
aliphatically) bound amino groups, wherein amino end groups can also
be attached to the polyether chain through urethane or ester groups.
15 Suitable compounds include, for example, Jeffamine D400 and
Jeffamine D-230, which are commercially available from Huntsman
Chemical Corporation.
These low molecular weight amine-terminated polyethers can be
prepared by any of several methods known in the art. For example,
20 amine-terminated polyethers can be prepared from polyhydroxyl polyether
(e.g., polypropylene glycol ethers) by a reaction with ammonia in the
presence of Raney nickel and hydrogen (Belgian Patent No. 634,741).
Polyoxyalkylene polyamines can be prepared by reaction of the
corresponding polyol with ammonia and hydrogen in the presence of a
25 nickel, copper, or chromium catalyst (U.S. Patent 3,654,370). The
preparation of polyethers containing amino end groups by the
hydrogenation of cyanoethylated polyoxypropylene ethers is described in
Germany Patent 1,193,671. Other methods for the preparation of
polyoxyalkylene (polyether) amines are described in U.S. Patents
30 3,155,728 and 3,236,895 and in French Patent No. 1,551,605. French
CA 02219693 1997-10-30
Mo4597 -30-
Patent No. 1,466,708 discloses the preparation of polyethers containing
secondary amine end groups. Also useful are the polyether polyamines
described in U.S. Patents 4,396,729, 4,433,067, 4,444,910 and
4,530,941.
Aminopolyethers obtained by the hydrolysis of compounds
containing isocyanate end groups can also be employed herein. For
example, in a process disclosed in 5erman Offenlegungsschrift
2,948,419, polyethers containing hydroxyl groups (preferably two or three
hydroxyl groups) react with polyisocyanate groups are then hydrolyzed in
10 a second step to amino groups. Preferred amine terminated polyethers
are prepared by hydrolyzing an isocyanate compound having an
isocyanate group content of frcm 0.5 to 40% by weight. The most
preferred polyethers are prepared by first reacting a polyether containing
two or four hydroxyl groups with an excess of an aromatic polyisocyanate
15 to form an isocyanate terminated prepolymer and then converting the
isocyanate groups to amino groups by hydrolysis.
Processes for the production of useful amine terminated
polyethers using isocy~nate hydrolysis techniques are described in U.S.
Patents 4,386,218, 4,456,730, 4,472,568, 4,501,873, 4,515,923
20 4,525,534, 4,540,720, 4,578,500 and 4,565,645; European Patent
097,299; and German Offenlegungsschrift 2,948,419, all the disclosures
of which are herein incorporated by reference. Similar products are also
described in U.S. Patent 4,506,039, 4,525,590, 4,532,266 and 4,532,317
and in U.S. Application Serial Nos. 437,641 (fiied October 19, 1982),
25 778,656 (filed September 23, 1985), 895,629 (filed August 11, 1986),
908,535 (filed September 16, 1986), and 916,923 (filed October 9, 1986).
The amine terminated polyethers used in the present invention are
in many cases mixtures with any of the above-mentioned compounds.
Preferred compounds containing amine groups to be used in the
30 present invention as low molecular weight isocyanate-reactive
CA 02219693 1997-10-30
Mo4597 -31 -
components include monoethanolamine, bis-(4-aminocyclohexyl)-
methane, and isophorone diamine. Monoethanolamine is particularly
preferred.
Other suitable amines to be used for the relatively low molecular
5 weight component in the present invention include, for example, aromatic
diamines such as, for example, 1-methyl-3,5-diethyl-2,4-diamino
benzene, 1-methyl-3,5-diethyl-2,6-diamino benzene, 1,3,5-trimethyl-2,4-
diamino benzene, 1,3,5-triethyl-2,4-diamino benzene, 3,5,3',5'-tetraethyl-
4,4'-diamino diphenylmethane, 3,5,3',5'-tetraisopropyl-4,4'-diamino
10 diphenylmethane, 3,5-diethyl-3',5'-diisopropyl-4,4'-diamino diphenyl-
methane, 3,3'-diethyl-5,5'-diisopropyl-4,4'-diamino diphenyl-methane, 1-
methyl-2,6-diamino-3-isopropylbenzene and mixtures of the above
diamines, such as, for example, mixtures of 1-methyl-3,5-diethyl-2,4-
diamino benzene and 1-methyl-3,5-diethyl-2,6-diamino benzene.
In accordance to the present invention, it is also possible that the
relatively low molecular weight isocyanate-reactive component comprises
one or more organic monofunctional alcohols. Examples of such
compounds include, for example, methanol, ethanol, 1-propanol, 2-
propanol, n-butanol, s-butanol, t-butanol, 2-ethyl-1-hexanol, stearyl
20 alcohol, and alkyl substituted phenols containing from 1 to 22 carbon
atoms in the alkyl group such as, for example, nonylphenol, and
especially alkoxylated phenols such as, for example, polyethoxylated
nonylphenols.
Suitable amine-group containing compounds which are
25 monofunctional include, for example, cyclohexylamine, propylamine,
butylamine, dibutylamine, hexylamine, mixtures thereof, and the like.
Preferred monofunctional compounds include n-butanol, 2-ethyl-1-
hexanol, cyclohexylamine, and dibutylamine.
It is also possible that the low-molecular weisht isocyanate-
30 reactive component include at least one organic crosslinker such as, for
CA 02219693 1997-10-30
Mo4597 -32-
example, organic polyols and/or organic amines containing greater than 2
isocyanate-reactive groups, and preferably 3 to 8 isocyanate-reactive
groups. Examples of such compounds include, for example,
diethanoiamine, triethanol-amine, pentaerythritol, trimethylolpropane,
5 glycerol, diisopropanolamine, mixtures thereof, and the like. Alkoxylated
polyols of the above mentioned starter compounds are also suitable
crosslinkers. Preferred compounds include diethanolamine, triethanol-
amine, trimethylolpropane, glycerol and pentaerythritol, alkoxylated
polyols of these starter compounds, and mixtures thereof.
It is, of course, also possible that other additives which may be
commonly used in RIM processes be include in the reaction mixture of
the present invention. Among these suitable additives are surface-active
additives such as emulsifiers and foam stabilizers. Examples include N-
stearyl-N',N'-bis-hydroxyethyl urea, oleyl polyoxy-ethylene amide, stearyl
15 diethanol amide, isostearyl diethanolamide, polyoxyethylene glycol
monoleate, a pentaerythritol/ adipic acid/oleic acid ester, a hydroxy ethyl
imidazole derivative of oleic acid, N-stearyl propylene diamine and the
sodium salts of castor oil sulfonates or of fatty acids. Alkali metal or
ammonium salts of sulfonic acid such as dodecyl benzene sulfonic acid
20 or dinaphthyl methane sulfonic acid and also fatty acids may also be
used as surface-active additives.
Suitable foam stabilizers include water-soluble polyether siloxanes.
The structure of these compounds is generally such that a copolymer of
ethylene oxide and propylene oxide is attached to a polydimethyl
25 siloxane radical. Such foam stabilizers are described, for example, in
U.S. Patent 2,764,565. In addition to the catalysts and surface-active
agents, other additives which may be used in the molding compositions
of the present invention include known blowing agents including nitrogen,
cell regulators, flame retarding agents, plasticizers, antioxidants, UV
30 stabilizers, adhesion promoters, dyes, fillers and rei~,rorcing agents such
CA 02219693 1997-10-30
Mo4597 -33-
as glass in the form of fibers or flakes or carbon fibers. Suitable
antioxidants include, for example, Irganox 245, and suitable UV
stabilizers include, for example, Tinuvin 765. However, any of the known
antioxidants and/or UV stabilizers may be used. As set forth
hereinabove, specific advantages have been found in reaction mixtures
containing antioxidants and/or UV stabilizers have been added.
It is also possible to use the known internal mold release agents,
such as, for example, zinc stearate, in the RIM process of the invention.
As is known to one of ordinary skill in the art, in the RIM process, an
10 isocyanate, and active hydrogen containing compounds are mixed and
injected into molds, wherein the reactants are allowed to react fully.
The molded products of the present invention are prepared by
reacting the components in a closed mold via the RIM process. The
compositions acccrding to the present invention may be molded using
15 conventional processing techniques at isocyanate indexes ranging from
about 80 to 130, preferably from about 95 to about 115. By the term
"Isocyanate Index" (also commonly referred to as NC0 index), is defined
herein as the equivalents of isocyanate, divided by the total equivalents
of isocyanate-reactive hydrogen containing materials, multiplied by 100.
In general, in a RIM process, two separate streams are intimately
mixed and subsequently injected into a suitable mold, although it is
possible to use more than two streams. The first stream contains the
polyisocyanate component, while the second stream contains the
isocyanate reactive components and any other additive which is to be
25 included.
Another aspect of the present invention are isocyanate-reactive
blends. These blends comprise 1 ) at least one isocyanate-reactive
component and 2) a catalyst composition comprising: a) one or more
organic tin carboxylates, and b) one or more chelating polyamines.
30 Suitable isocyanate-reactive components for these blends include the
CA 02219693 1997-10-30
Mo4597 -34-
high molecular weight components which contain hydroxyl groups and/or
amine groups as described above, as well as the low molecular weight
components containing hydroxyl and/or amine groups as described
above. In addition to the isocyan3te reactive components and the catalyst
combination, these isocyanate-reactive blends may also contain additives
which are known per se in polyurethane chemistry. Suitable additives
include components such as, for example, surface-active additives, foam
stabilizers, blowing agents, flame retarding agents, antioxidants, internal
mold release agents, fillers, reinforcing agents, etc.
The following examples further illustrate details for the process of
this invention. The invention, which is set forth in the foregoing
disclosure, is not to be limited either in spirit or scope by these examples.
Those skilled in the art will readily understand that known variations of
the conditions of the following procedures can be used. Unless otherwise
noted, all temperatures are degrees Celsius and all parts and
percentages are parts by weiglht and percentages by weight, respectively.
EXAMPLES
Example 1
A B-side mixture (i.e., an isocyanate reactive blend) was prepared
by blending the desired parts by weight (pbw) of each of the following
compounds: Polyol A, Diol A, Pigment A, Irganox 245, Tinuvin 765 and
Catalyst A together and thoroughly mixed. They were put into the B-side
of a Hennecke RIMDOMAT RIM machine. The appropriate quantity of
Isocyanate A to achieve an isocyanate index of 105 was loaded into the
A-side. The RIMDOMAT was eq~ipped with a Hennecke mq8 Mixhead.
The B-side and the A-side for each example were heated to the
temperature as specified in Table A. The materials were injected at a
105 isocyanate index at an injection pressure of 200 bar and an injection
rate as specified in Table A. The material was injected into a flat plaque
mold of 3x200x300mm, wherein each plaque mold was heated to the
CA 02219693 1997-10-30
Mo4597 35
temperature as specified in Table A, and sprayed with Chemtrend 2006
soap mold release spray. After a 30s dweil time, the part was demolded.
Physical properties were determined in accordance with ASTM
standards. Other RIM examples were performed in an identical manner,
5 except for the pbw of various components.
The following ASTM methods were used to determine the
properties of the molded parts:
Flexural Modulus: D3489 (D790 Method 1)
Density: D3489
Tensile Strength: D3489 (Die B, 20"/min.)
Die C Tear: D624 and D3489
The following components were used in Examples 1-12 presented
in Tables 1 through 3 below.
Polyol A: a glycerine started propyleneoxide/ethylene oxide polyether
polyol (82.5 wt.% PO, 17.5 wt.% EO) and having an OH
number of about 28
Polyol B: a styrene acrylonitrile polymer polyol having a solids content
of about 28%, and containing a mixture of styrene to
acrylonitrile, commercially available as Arcol E-519 from
Arco Chemicals. This polymer polyol has and OH number
of about 25.4, a functionality of about 3, and a PO:EO wt.
ratio of 81 :1 9.
Polyol C: a polyacrylonitrile polymer polyol having a solids content of
about 21%, commercially available as Arcol 31-28 from
Arco Chemicals. This polymer polyol has an OH number of
about 28, a functionality of about 3, and a PO:EO wt. ratio
of about 85;15.
Polyol D: a glycerin started propylene oxide/ethylene oxide polyether
(87 wt.% PO, 13 wt.% EO) and having an OH number of
about 28
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Diol A: 2-methyl-1 ,3-propanediol
MEOA: monoethanclamine
Alcohol A: 2-ethylhexanol
Triol A: trimethylolpropane
5 TEOA: triethanolamine
Catalyst A: Fomrez UL-28, dimethyltin dilaurate, commercially
available from Witco Corp.
Catalyst B: pentamethyl diethylenetriamine, commercially available as
Polycat 5 from Air Products.~0 CatalYst C: propoxylated ethylene diamine having an OH number of
about 630
Catalyst D: N',N'-dimethylaminoethyl N-methyl ethanolamine,
commercially available as DABCO T from Air Products.
Irqanox: an antioxidant, commercially available as Irganox 245 from
Ciba-Geigy Inc.
Tinuvin: an UV stabilizer, commercially available from as Tinuvin
765 Ciba-Geigy Inc.
Pi~qment A: a blend of Diol A (85 wt.%) and carbon black (15 wt.%).
Piqment B: a blend of Polyol D (91.1 wt.%) and carbon black (8.9
wt.%).
Iso A: a polyisocyanate containing isocyanurate and allophanate
groups, having an isocyanate content of 21.0%, a content
of monomeric diisocyanate of <0.05% and a viscosity at
25~C of 1010 mPa s. This polyisocyanate was prepared by
reacting 1,6-hexamethylene diisocyanate with n-butyl
alcohol in the presence of a trimeli~alio,l catalyst; and
prepared by the following procedure:
To a reactor equipped with a gas bubbler, stirrer, thermometer and
dropping funnel 100 parts of hexamethylene diisocyanate (HDI) were
30 added. The stirred HDI was heated to 90~C while dry nitrogen was
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bubbled through the HDI. To the stirred HDI, 2.0 parts of 1-butanol,
containing 0.00003 parts of trimethylbenzyl ammonium hydroxide were
added, at such a rate that the 90~C temperature was maintained. After
the addition was complete, the reaction mixture was held at 90~C until a
5 crude NCO content of about 38.5% was attained. Then, 0.0003 parts of
di(2-ethylhexyl)phosphate were added. The excess monomer was
removed by wiped thin film evaporation to provide an almost colorless
(APHA 25) liquid having a viscosity of 1010 mPa s at 25~C, an NCO
content of 21.0%, and a free monomer (HDI) content of 0.05%.
Iso B: a polyisocyanate containing isocyanurate and allophanate
groups, based on 1,6-hexamethylene diisocyanate, having a
viscosity of about 822 mPa s at 25~C, an NCO content of
about 19.3%, and a free monomer content of about 0.22%
by weight; and prepared by the following procedure:
To a reactor equipped with a gas bubbler, stirrer, thermometer and
dropping funnel 100 parts of hexamethylene diisocyanate (HDI) were
added. The stirred HDI was heated to 90~C while dry nitrogen was
bubbled through the HDI. To the stirred HDI, 4.4 parts of 1-butanol,
containing 0.00003 parts of irimethylbenzyi ammonium hydroxide were
20 added, at such a rate that the 90~C temperature was maintained. After
the addition was complete, the reaction mixture was held at 90~C until a
crude NCO content of about 34.6% was attained. Then, 0.00003 parts of
di(2-ethylhexyl)phosphate were added. The excess monomer was
removed by wiped thin film evaporation to provide an almost colorless
25 (APHA 25) liquid having a viscosity of 822 mPa;s at 25~C, an NCO
content of 19.3%, and a free monomer (HDI) content of 0.22%.
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Table A:
Example Polyol Iso. Temp. Mold Temp. Inject. Rate
Temp. (~C) (~C) (~C) (glsec)
150
2 55 65 80 117
3 55 55 70 150
4 45 55 75 117
150
6 55 55 75 150
7 45 56 75 162
8 50 60 70 175
9 50 55 67 117
162
11 50 55 67 124
12 50 55 67 117
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Table 1:
Example 1 2
Polyol A 67.8 68.5
Diol A 10.2 17
MEOA 4 4
Alcohol A 4 4
Tinuvin 3 3
Irganox
PigmentA 8
Catalyst A 2
Catalyst B 0.5
Iso Index 105 105
Iso B B
Shot Time (seconds) 1.4 1.8
Pressure Transducer Reading (bar) 5 3
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Table 2A:
Example 3 4 5 6
Polyol A 67.8 65.2 67.4 71.8
Diol A 10.2 11.5 10.2 10.2
MEOA 4 4 4 4
Triol A 4
TEOA 4.4
Tinuvin 3 3 3 3
Irganox
10Pigment A 8 8 8 8
Catalyst A 2 2 2 2
Catalyst C 5.3
ISO Index 105 105 105 105
Iso B B B B
15Shot Time 1.4 1.8 1.4 1.4
(seconds)
Pressure 10 2 10 5
Transducer
Reading
20 (bar)
Table 2B:
Example 3 4 5 6
Direction PP PA PP PA PP PA PP PA
Density (Ibm3) 69.7 69.7 69.7 69.7 69.7 69.7 69.4 69.4
Flexural Modulus 9866 27,540 8722 13,373 6927 17,647 3422 10,440
(psi)
% Elongation 86 57 91 75 105 79 87 66
Tensile strength 1638 1340 1486 1267 1685 1351 1038 995 D
(psi) O
Die C Tear (pli) 221 269 231 241 199 248 78 121
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5 Table 3:
Example 7 8 9
Polyol A 69.8 58.8 32
Polyol B 32
DiolA 12.2 14.2 12
MEOA 4 5 4
Alcohol 8 8
Triol A
Tinuvin 3 3 3
Irganox
Pigment A 8 8
Pigment B 4
Cat. A 2 2 2
Cat. C 2
Iso Index 105 105 105
Iso A A A
Shot Time (seconds) 1.3 1.2 1.8
Pressure Transducer Reading 10 5 5
(bar)
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Table 3B:
Example 7 8 9
Direction PP PA PP PA PP PA
Density 69.5 69.5 68.9 68.9
(Ibm3)
Flexural 14,661 237683 2670 3535
Modulus
(psi)
% 81 77 87 88
1 0Elongation
Tensile 1929 1925 863 891
Strength
(psi)
Die C Tear 84 91 103 116
1 5 (pli)
. CA 02219693 1997-10-30
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Table 4A:
Example 10 1 1 12
Polyol A 71.5 28.4 24.4
Polyol C 50.6 45.6
Diol A 9 12 12
MEOA 4.7 4 4
Alcohol 8
Triol A 0.3
Tinuvin 3.4 3 3
Irganox 1.1
Pigment A 8
Pigment B 4 4
Cat. A 2 2 2
Cat. C 2
15 Cat. D
Iso Index 105 105 105
Iso A A A
Shot Time (seconds~ 1.3 1.8 1.8
Pressure Transducer Reading 10 3 5
(bar)
Table 4B:
Example Example 10 Example 11 Example 12
Direction PP PA PP PA PP PA
Density 69.6 69.6 68.9 68.9
(Ib/ft3)
Flexural 5040 29,053 2893 5321
Modulus
(psi)
% 70 56 92 79 D
Elongation O
Tensile 1694 1781 965 922 ~,
Strength , ~,
(psi)
Die C Tear 93 116 124 141
(pli) O
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The pressure transducer readings are an indication of the viscosity
of the reacting system. The lower the transducer reading, the lower the
viscosity. A lower viscosity means that the system is farther away from
the gel point and has better flow characteristics.
The shot time also gives an indication of system reactivity. For a
given pressure transducer reading, a longer shot time means a lower
reactivity since the reacting polymer would have the same viscosity after
a longer residence time in the mold. In all the examples containing a
chelating polyamine, the shot times are longer and the transducer
10 reading are lower than the similar formulations which do not contain a
chelating polyamine.
The lower reactivities of systems containing chelating polyamines
manifests itself in more isotropic properties, especially flexural modulus.
Note, in particular, the lower ratio of parallel to perpendicular flexural
15 moduli for the examples which contain a chelating polyamine vs. the
examples which do not contain a chelating polyamine.
Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be understood that such
detail is solely for that purpose and that variations can be made therein
20 by those skilled in the art without departing from the spirit and scope of
the invention except as it may be limited by the claims.
