Note: Descriptions are shown in the official language in which they were submitted.
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-- ;
1~33V~
This invention relates to catalysts; more particularly, this
invention relates to catalysts for the production of polyesters and
polyurethanes.
Batch-to-batch variability is a serious problem encountered
industrially in polyurethane production. A wide variety of compounds
will catalyse or co-catalyse the isocyanate-alcohol reaction; in
addition, trace contaminants in the reactants themselves, e.g.
polyesterification catalysts, can also be polyurethane catalysts and
thus contribute to this variability. The effect of such contaminants
can be minimised by the use of highly active catalysts but this itself
gives rises to serious variability problems by causing the polyure- !
thane reaction to commence before the components are completely mixed.
These problems would be minimised if a highly active catalyst `
having a delayed-action effect could be developed~ However, such
compounds so far developed with this property are organo-mercury
compounds which are extremely expensive and present a severe
toxicity hazard.
This invention seeks to provide catalysts having a delayed-action
effect which can be produced more economically.
The present inventlon in one a~pelt prnYide~q compol1nd~q of t~ ormllla;
r~
3 Sn t Q - Sn t OOCQ~C00~4
Z
~'
3~0~
wherein:
Q and Q' which may be the same or different, each represent a
group of the formula ~CH2~n or an arylene group, preferably a phenylene
group, most preferably an ortho-phenylene group; Rl, R2, R3 and R4, which
may be the same or different, each represent an unsubstituted al~yl group;
each n, independently representg zero or an integer from 1 to 10, prefera-
bly from 1 to 6; and x represents zero or an integer less than 6, prefera-
bly less than 4, especlally 1. As noted above, in the above formulae Rl,
R2, R3 or R4 represent an unsubstituted alkyl group, for example a Cl to
C6 alkyl group, preferably a Cl to C4 alkyl group. Generally, Rl and R2
will be identical and it is particularly preferred that they both represent
butyl groups. Suitably, R3 and R4 will be identical. It is preferred
that R3 and R4 each represent an ethyl or a butyl group.
It is believed that when x = 1, and possibly when x ~ 1, these
compounds exist in an associated form. When x = 1 the structure may be a
dimer of the formula:
C - 2 -
1~330~1
, ¦ 2 4
R3oocQcooR2Rlsn / SnRlR~oocQlCOOR4
O ~
SnRlR200CQcOoR3
It is not known whether, at the low concentrations encountered in poly-
urethane-forming reactions, these compounds are sssociated or not.
The above mentioned compounds of aspects of the invention are
catalysts per se for the production of polyurethane. These compounds of
aspects of the invention can also react with dihydroxyl compounds, for
example glycols and polyetherglycols, under ester interchange conditions
. . .
~ - 3 -
to produce poly~eric tin-containing es ter~ having hydroxyl groups in the
terminal positions. These latter compounds, too, are also found to be
catalysts for polyurethane-production. Furthermore, such catalytic poly-
meric tin-containing esters also react with isocyanates to produce tin-con-
taining polyurethanes which are themselves catalysts for further polyure-
thane production.
The first-mentioned class of compounts of aspects of the inven-
tion (hereinafter referred to as monomeric or telomeric tin-containing di-
esters) may be prepared in accordance with a process of another aspect of
the invention, by reacting a compound of the empirical formula:
RlR2Sn
with a dicarboxylic acid alkyl ester of the formula:
R300CQCOOH and/or R400CQ'COO~
wherein Rl, R2, R3, R4, Q and Q' are hereinabove defined.
By a variant thereof, the tin oxide is reacted with the acid
alkyl ester in a stoichiometric ratio of 1:1 thereby providing a compound
wherein x a 1~
: ~ - 4 -
~1~330~
By another variant, the process is carried out in an anhydrous
hydrocarbon solvent.
By yet another variant, the solvent is sodium-dried.
For example, dibutyl tin oxide may be reacted with adipic acid
monoethyl ester of phthalic acid monobutyl ester. The reactants are
suitabIy mixed in~the appropriate stoichiometric ratio and reaction is con-
veniently carried out in an organic solvent, for example toluene or other
hydrocarbon, preferably sodium-dried. The reaction products separate on
cooling or after evaporation of the solvent.
. ~
11330~
The class of compound of an aspect of this invention is a
catalysts for the production of polyurethanes, the polymeric species
giving rise to very smooth rapid reactions. WheLe foam products are pro-
duced from them, these are of very fine texture. In additlon to showing
catalytic activity the compounds of this invention are non-volatile
stabilisers for polyvinylchloride.
This invention in yet another aspect provides a p~lyurethane
prepared using a polymeric tin-containing ester and/or tin-containing
catalytlc polyurethane of the present invention and/or a catalyst of the
formula:
X - Sn ~ - Sn ~ ~ Y
I \ ~
R2 \ R2 ~ ~L
wherein:
R1, R2 and x are herein above defined; and
X and Y which may be the same or different, each represent a
monoester of a dicarboxylic acid.
- 6 -
,~,
il33~
G~l times measured for test-eube scale reactions of polyols with
toluene diisocynate (TDI) and with dlphenylmethane diisocyanate (MDI)
are given in Tables 1 and 2. The efficiency of the polymeric catalyfits
can be seen for the case when such a catslygt was prepared as a master-
batch $n the polyol so that the concentration of tin in the mixture would
be roughly equivalent to that in similar experiments with the monomeric
or telomeric tin-containing diesters: the effect on gel time can be seen
in Table 2. Catalysts of this nature will be
-- 7 --
~i33(~ .
particularly useful for systems where very short reaction times are
required (e.g. short cycle reactions moulding) and where high
catalyst concentrations may prove to be uneconomic or undesirable.
When reac~ion ratesare compared in tcrms of 1he respective gel
times then it is clear that the monomeric or telomeric tin-containing
diesters are a1so efficient catalysts and are indeed faster than
conven+ional cat~ly~t~ e.g. Dl)TL. IlOWeVIn` when Ibsolute reaction
rates are measuled for dilute s(>lutioll reactioJIs then it become~
apparent that the 1:~ mon<llleric tin ester gives a somewhat slower
reaction th~n Dl3TL when equivalent concentrations (either mole %
or wt ~) oL catalyst are used (Table 3). Iiowever tl-is relationship r
is reversed when the temperature is increased.
In this case the reaction under invest;gation was that of
iso-propanol (0.01 mole) with phenyl isocynnate (0.01 mole) in dry
15 toluene (100 ml) at ambient temperature (22 - 2IJ C) and at an r
elevated temperature of 45 C. Re.sidual i~ocyal1ate ill the reaction
mixture was monitored during the reactiol1 by taking an aliquot (5 ml)
of the mixtuJe and di~esting this in a mixtule of dry alld redistilled
toluene (50 m1) and di-n-buty1amine (50 ml 0.2N so1ution in toluene).
This mixture was left to stand for 15 minutes and then residual
amine was estimated by adding iso-propanol (225 m1) to the mixture
and then titratinl a-lainst O.lN HCl using hromocressol green as
indicated.
TABLE 1
Examples of results for small scale reactions at 30 C
Catalyst type Wt. of catalyst (mg) Gel time (min.)
DBTL 20
1:1 MTE 20 4
Tin-containing ( 40 60
polyester
(Example 6) ~ 80 11
Tin-containing ( 40 24
polyurethane
(Example 7) ( 80 14
,_",~
~;w~
TABLE 2
Summary of results for small scale reactions at 70C
Wt ~ MDl Wt. of polyether Wt. of catalyst Gel ~ine
Catalyst type (g) (g) (mg) (min-sec)
DBTL 1.48 5-92 0.11 15-00
DBTL 1.49 5.96 18-15
0.5:1 TTE 1.35 5.40 0.09 9-10
0.5:1 TTE 2.00 8.oo 15-00
1:1 MTE 1.48 5.92 0.13 13-10
1:1 MTE 2.06 8.24 15-30
2:1 MTE 1.24 4.96 7~3
2:1 MTE 1.4~ 5.76 0.12 8-30
2:1 MTE 1.96 7.84 10-00
MTE combined 1.81 7.24 2-00
with poly- 0.13
(Example 5) 1.83 7.32 2-30
11;~300~
TABLE 3
Summary of results for solution reactions
c"3 catalyst (0.1 mole %)
C6H NC0 ~ ~ CIIOH
5Cl~3 ~ toluene (100 ml)
0.01 mole 0.01 mole
Catalyst type Temperature % conversion
60 min.
m~ e
(22 - 2l~C)
DBTL amb;ent 5o
1:1 M'l`E ~5 C ~6
DBTL l~5 C 81
113;~00~
The increase in catalytic efficiency of the 1:1 MTE as
the temperature increases can be utilised to provide a delayed
action effect in larger scale bulk systems. This effect is
demonstrated in Figure 1, in which curves showing the build-up
in viscosity with time, for polyurethane elastomer formation,
are presented. The results obtained with the 1:1 momomeric
tin-containing diester (x = 1 in the generic formula) are
represented by curves 1c and ld. These may not be obtained
in the research laboratory if a small bulk, thermally
uninsulated system is used since the initially slow exotherm
would not be adequately conserved to raise the temperature
sufficiently (typically 45 C) to give the catalyst the required
activation after the delay period. Conversely, if too high
an initial temperature (75 C, for example) is used the catalyst
is immediately activated and no delay period is observed.
Referring now in more detail to Figure 1, there are disclosed
four kinetic plots of viccosity (cps) (log scale), as a measure of
the amount of polyurethane formed, versus reaction time (min.).
The reactants were polyether glycol and toluene diisocyanate
initially maintained at 22 C. Curve (a) is a plot in which the
catalyst is 64 ng (lng = 10 9g) of dibutyltin bis(ethyl adipate);
curve (c) in which the catalyst is 6~ ng of bis(ethyl adipatodibutyltin)
oxide; and curve (d) in which the catalyst is 32 ng of bis(ethyl
adipatodibutyltin) oxide. Curve (b) is a reference plot in which
the cata~yst is 128 ng of dibutyltin laurate (DBTL).
1133001
The viscosities in each run were measured as follows.
Into a ~iOOml beaker was measured a 250g sample of previously
dried poly(oxypropylene) glycol (PPG) of Md. Wt. 1000. The
beaker and its content~ were then placed in an insulating block
of polyurethane foam. This block measured 22cm x 2Zcm x lOcm
and the beaker was placed in a central cut out of 7cm depth.
A dilute solution of the appropriate tin ester in toluene
(typically 0.1g in 1 li,tre) was prepared and microlitre
guantities were added to the PPG with a syringe. A Brookfield
Viscometer (Model HBT) was fitted with spindle No. 1 and the
spindle was immersed in the liquid upon the groove on the stem,
care being taken to ensure that no air was trapped under the
spindle. The viscometer was switched on at a spindle speed of
100 r.p.m.
Toluene diisocyanate (43.54g) was added to the contents of ~'
the beaker and timing was commenced. The viscosity of the liquid
was measured at one minute intervals throughout the reaction until
gelling occurs.
In addition to the desirable delayed action effect noted above,
it will be seen that the monomeric tin die~sters of an aspect of the
invention are much more reactive than the conventional DBTL catalyst. As
i,s genera1 with such systems the presence of a small amor~nt of cata]yst,
typically 15 to 20 ng in the above system, was required in order
to obtain any catalytic effect.
1133(~0~
EXAMPLE 1
sy~T~Esrs OF 2:1 MONOMERIC TIN-CONTAINING DI-ESTER
15g of dibutyltin oxide (0.06mole) and 21g of adipic
acid monoethyl ester (0.12mole) were placed in a one litre
flask and 750 ml of redistilled sodium-dried toluene were
added. On heating to the boil a clear solution was formed
and an azeotrope of toluene and water was distilled off as
rapidly as possible. Distillation was continued until a
volume of about 100ml of solution remained. This solution
was placed in a 150ml flask and heated under vacuum (water
vacuum pump) over ~5 minutes while the temperature rose to
130 C. The oil vacuum pump was then applied (pressure
1-2mmHg) and the remainder of the solvent was distilled off
at 130 C. The reaction product was a clear, amber liquid.
EXAMPLE 2
SYNTHESIS OE 1:1 MONOMERIC TIN-CONTAINING DI-ESTER
15g of dibutyltin oxide (0.06mole) and 10.5g of adipic
acid monoethyl ester (0.06mole) were placed in a one litre flask
and 750ml of re-distilled sodium-dried toluene is added. On heating
to the boil, a clear solution was formed and an azeotrope of toluene
and water was distilled off. Distillation was continued until a
volume of about 100ml of solution remained. This solution was placed
in a 150ml flask and heated under vacuum (water vacuum pump) over l~5
minutes while the temperature rose to 130 C. The oil vacuum pump
was then appl ied (pressure 1-2mm H~) and the remainder of the solvent
was distilled off at 130 C. The reaction product was a clear, amber liquid.
1133S)01
EXAMPLE 3
SYNTHESIS OF 0.5:1 TELOMERIC TIN-CONTAINING DI-ESTER
15g of dibutyltin oxide (0.06mole) and 5.259 of adipic
acid monoethyl ester (0.03mole) were placed in a one litre
flask and 750ml toluene was added. On heating to the boil,
a clear solution was formed and an a7eotrope of toluene
and water was distilled off. Distillation was continued
until a volume of about 100ml of solution remained. On
coo]ing a fine white plecipitate of dibutyl tin oxide (0.98g)
was forrned and was filtered off. The solution was placed in
a 150ml flask and heated under vacuum (water vacuumpump) over
45 minutes while the temperature rose to 130 C. The oil
vacuum pump was then~applied (pressure 1-2mm Hg) and the
remainder of solvent was distilled off at 130 C. The reaction
product was an amber glassy solid which softened at around 150 C
to a clear, amber liquid.
EVIDENCE FOR STRUCTURES OF MONOMERIC TIN-CONTAINING DI-ESTERS
2:1 Monomeric Tin-containing Diester (2:1 MTE)
Infrared spectroscopy (Figure 2 of the accompanying drawings)
showed the product to be substantially free of either of the two
reactants. There was no evidence for the presence of stannoxane
group. An absorption characteristic of carboxylate was observed
at 6.22~m (1608 cm ).
1133(~
The presence of this absorption band and the fact that none
of the reactant ester was distilled out during the reaction lead
to the conclusion that the product is probably dibutyltin bis
(ethyl adipate):
IC4H9
C2l{500C(CI{2)4C00-Sn-OOC(CH2)4COOC2H5
c4l~9
The results of micro-analysis support this assignment (Found:
C~ 50.0; H, 7.6; 0, 21.5/'o, C24H/l40gSn requires C~ 49-8;
H,7.6; 0, 22.1% )
1:1 Monomeric Tin-Containing Diester (1:1 MTE)
Infrared spectroscopy (Figure 2b of the accompanying
drawings) showed the product to be substantially free of either
of the two reactants; the spectrum was characterised by a strong
absorption of 15.75~m (635 crn ) characteristic of Sn-0-Sn. A 300 MH
~H NMR spectrurn of the product (in CCll) has been obtained (Figure 3 of
the accompanying drawings). The assignments shown in the figure are
~5 obtained by reference to the spectrum of adipic acid monoethyl ester:
the integrations are consistent with a 1:1 adduct of this ester and
dibutyltin oxide. The spectral evidence is consistent with the reaction
product being bis(ethyl adipatodibutyltin) oxide as are the results
of micro-analysis (Found: C, 46.4; H, 7.7; 0, 17.7%; C32H6209Sn2
requires C, 46.l~; H, 7.5; 0, 17.4%).
16
1133~01
The presence of infrared absorption bands at 20.5~m
(485 cm ) and around 6-6.5~m suggests that this stannoxane
may be associated in some wayt possibly as a cyclic dimer.
The unassociated structure is pr-obably:
ClkH9 ~C4~19
C2H500C(Cll2)4 COO - Sn - O - Sn - OOC(CH2)4COOC2H5
C4H9 C/H9
0.5:1 Telomeric Tin-containing diester (0.5:1 TTE)
Infrared spectroscopy (Figure 2c of the accompanying
drawings) showed the product to be substantially free either
of the two reactants; the spectrum was characterised by a
strong absorption at around 1~ m characteri~tic of Sn-O-Sn.
In view of the reaction stoichiometry and the polymeric nature
of dibutyltin oxide, a polystannoxane structure is suggested
(x~ 1 in the generic formula). The results of micro-analysis
are consistent with a structure for which the mean value of
x is 3 (Fol~nd C, 43.5; H, 7.7; O, 13-5%; C48~g8011Sn4 requires
C, 43.5; H, 7./l; o, 13.5%).
EXAMPLE 4
SYNTHESIS OF POLYMERIC TIN-coNTAINING ESTER
0.5g (0.33mmole, 1 meq) of dry poly(oxypropylene) triol of
MW 1500 and 0.29g (0.50mmole, 1 meq) of 2:1 MTE were placed in a
B24 test-tube equipped with a Drechse1hea~1and the mixture was
heated for ~ hours using an oil bath at 180 C whilst nitrogen
(oxygen-free grade) was passed through the inside of the test-tube.
il;~3001
The product was a viscous liquid which did not flow under its
own weight and which had an infrared spectrum possessing only
a very weak absorption characteristic of hydroxyl, but showing
a strong absorption at 5.78 ~ m, 1730 cm ; characteristic of
ester carboxyl.
EXAMPLE 5
SYNTHESIS OF POLYMERIC TIN-CONTAINING ESTER
A solution containing 1~1 (1.2mg, 2.1~mole) of 2:1 MTE
in 5ml dichloromethane was added to 70 ml (66g, 44mmole) of dry
poly(oxypropylene) triol of MW 1500 and the mixture shaken until
visually uniform. The dichloromethane was then removed from
this mixture by evaporation under reduced pressure. The reaction
mixture was then placed in a 150ml two-necked flask equipped with
gas inlet and outlet tubes. The mixture was then heated for 2-3
hours using an oil bath at 175 C whilst nitrogen (oxygen-free
grade) wa.s passed through the flask. The product obtained was
a clear and colourless free-flowing liquid.
EXAMPLE 6
SYNTHESIS OF POLYMERIC TIN-CONTAINING ESTER
37g (20mmole) of poly(tetramethylene adipate) of MW 1830
and 10g (12 mmole) of 1:1 MTE were placed in a 100ml three-necked
flask equipped with a thermometer, gas inlet tube and Leibig
condenser. Some antibumping granules were added and the mixture
was heated for 3-5 hours at 175 C whilst nitrogen (oxygen-free grade)
was passed through the flask. The nitrogen flow was stoppeA and the
~8
.o
1133001
flask was evacuated (rotary oil pump) and the mixture was heated
under vacuum for a further 20 minutes. The hot reaction product, a
clear viscous liquid, was poured into an aluminium tray to solidify.
EXA~IPLE 7
SY~'THESIS OF TI~-CONTAINING CATALYTIC POLYURETHANE
ln the three-necked flask of capacity 100 ml equipped with a
stirrer, reflux condenser, gas inlet tube, thermometer and dropping
funnel, 15 9 of the polymeric tin-containing diester was dissolved
in 25 ml ethyl acetate at 60 - 70 C. Then temperature was lowered
to 40 C and the suspension of 0.5 g diphenylmethane diisocyanate (~1DI)
in 5 ml ethyl acetate was added dropwise over 3 minutes with continuous
stirring of the reaction mixture. The dropping funnel was then washed
with 2.5 ml ethyl acetate and this was also added to the reaction
mixture. Immediately after the ~lDI has been added the temperature
inside the flask increased to ~3 - ~5 C. After 15 minutes the
reaction mixture was heated to 50C and this temperature was maintained
over 45 minutes. Then the temperature was raised to 60 C and the
reaction mixiure maintained at this temperature over 1 hour~ and
finally taken up to the boiling point (approximately 78& ) and boiled
ZO for over 1 hour. The reaction mixture (clear yellow liquid) was then
evaporated at room temperature and waxy-white-yellowish product was
obtained.
EX~1PLE 8
SYNT~ESIS 0~ PO~YU~ET~ANE ELASTO~ER AT 30 C
12.15 ~ (30 mmole, 61 meq.) of dry poly(oxy~ropylene) glycol
of ~ 400 and a small amount of catalyst (typicaily 10 - 80 mg3 were
19
11~3~)0~
mixed in a B24 test-tube (N.B., when polymeric catalysts are used
this mixture was heated up to 80 C and mixed until solution occurred
and then cooled to room temperature before further reagents were
added). 8.10 9 (2.7 mmole, o.1 meq.) of dry poly(oxypropylene) triol
of MW 3000 and 5.0 ml (6.1 9, 70 meq.) of toluene diisocyanate (TDI)
were added to the reaction mixture. The mixture was placed in a
constant témperature bath at 30 C and was stirred for 1 minute.
EXAMPLE 9
SYNTHESIS OF POLYURETHANE ELASTOMER AT 70 C
Equivalent quantïties of poly(oxypropylene) triol (ca. 6 9)
of MW 1500 and MDI (ca. 1.5 9) were mixed with a small amount of
catalyst (ca. 0.1 mg) in a B24 test-tube. The test-tube was placed
in a 70 C oil bath and the mixture was stirred for 1 minute.
EXAMPLE 10
SYNTIIESIS OF POLYURETHANE FOAM
The polyether and catalyst were pre-mixed as above. Water (0.5 9)
and silicone oil (0.25 9) were added to a mixture of 12 9 of poly(oxy-
propylene) triol of MW 3000 and 20 - 80 mg of catalyst 5 ml of TDI
were then added and the mixture was warmed to 30 C and stirred over
20 15 - 20 seconds.
EXAMPLE 11
SYNTHESIS OF 1:1 MONOMERIC TIN-CONTAINING DIESTER OF AN AROMATIC ACID
15 9 of dibutyltin oxide (o.o6 mole) and 13.3 g of phthalic acid
monobutyl ester (o.o6 mole) were placedinaone litre flask and 750 ml
25 of re-distilled sodium-dried toluene is added. On heating to the boil,
the solution began t~ clear and the azeotrope of toluene and water was
1133~0~
distilled off. Distillation was continued until a volume of about
100 ml of solution remained. This solution was placed in a 150 ml
flask and heated under vacuum (water vacuum pump) over ~5 minutes
while the temperature rose to 130 C. The oil vacuum pump was then
applied (pressurel-2 mm Hg) and the remainder of the solvent was
distilled off at 130 C. The reaction product was an amber liquid.
The infra-red spectrum was consistent with the product being
principally bis(butyl phthalatobutyltin) oxide.
21
