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TECHNICAL FIELD
The present invention relates to a catalyst for alkylene oxide ring-opening
polymerization, a method for producing a double metal cyanide complex
catalyst, a method for producing a polyether polyol obtainable by using
the catalyst for alkylene oxide ring-opening polymerization, a method for
producing a polyurethane compound obtainable by using said polyether
polyol, a method for producing a resilient polyurethane foam, and a method
for producing a polyurethane elastomer.
BACKGROUND ART
It has been known to produce a resilient polyurethane foam and a
polyurethane elastomer, by reacting a polyether polyol with an isocyanate
group-containing low molecular weight compound in the presence of a
foaming agent. An alkali catalyst such as potassium hydroxide has been
known as a catalyst for producing said polyether polyol.
In a case of producing a polyether polyol by subjecting an alkylene oxide
to a ring-opening polymerization reaction by using said alkali catalyst, a
monol (unsaturated monol) having unsaturated groups will be formed as
by-product, and the amount of the unsaturated monol will increase with the
increase in the molecular weight of the polyether polyol (decrease in
hydroxyl number X). Accordingly, with a polyether polyol having a hydroxyl
number of 34, for example, the unsaturation is usually at a level of 0.08
meq/g.
In a case of producing a resilient polyurethane foam by using this
polyether polyol having a relatively high unsaturation of a level of 0.08
meq/g, problems may arise such as decrease in hardness, decrease in ball
rebound, deterioration in compression set, and decrease in curing property
at the time of forming a foam.
Further, in a case of producing a polyurethane elastomer by using a
polyether polyol having a relatively high unsaturation, problems may arise
such as insufficiency in strength, decrease in elongation and failure in
tack.
On the other hand, it has been known to use a double metal cyanide complex
as a catalyst for ring-opening polymerization reaction of an alkylene
oxide (U.S. Pat. Nos. 3,278,457-9). A method for producing a double metal
cyanide complex is disclosed in e.g. U.S. Pat. No. 3,427,256, U.S. Pat.
No. 3,941,849, U.S. Pat. No. 4,472,560 and U.S. Pat. No. 4,477,589, and a
method for producing a polyether polyol by using a double metal cyanide
complex as a catalyst is disclosed in e.g. U.S. Pat. No. 4,055,188 and
U.S. Pat. No. 4,721,818.
Further, e.g. JP-A-3-14812 discloses that in a case where a resilient
polyurethane foam is produced by using a polyether polyol produced by
using a double metal cyanide complex as a catalyst and having, for
example, a hydroxyl number of 34 and a low unsaturation of at most 0.02
meq/g, the above-mentioned problems such as decrease in hardness, decrease
in ball rebound, deterioration in compression set, and decrease in curing
property at the time of forming a foam, can significantly be overcome, and
further, comfortableness to sit on will improve. However, it has been
still desired to improve molding properties, particularly easiness in
crushing.
Further, JP-A-4-145123 and JP-A-8-311171 disclose to use tert-butyl alcohol
as a ligand for the double metal cyanide complex. In a case of producing a
resilient polyurethane foam by using the polyether polyol produced by
using said double metal cyanide complex as a catalyst, molding properties
of the obtained foam are also inadequate, particularly in view of
uneasiness in crushing. Further, the polyether polyol produced by using
said double metal cyanide complex as a catalyst, has a spread
molecular-weight distribution and a high viscosity and unfavorably
influences physical properties of the obtained polyurethane elastomer if
the molecular weight per hydroxyl group exceeds about 3000.
Further, U.S. Pat. No. 5,627,120 discloses to use tripropylene glycol
monomethyl ether as a ligand for the double metal cyanide complex. In a
case of producing a resilient polyurethane foam by using the polyether
polyol produced by using said double metal cyanide complex as a catalyst,
the molding properties of the obtained foam are also inadequate
particularly in view of uneasiness in crushing.
In recent years, various studies have been made to improve performances of
a resilient polyurethane foam. Particularly, along with enlargement of a
sheet cushion, increase in the thickness of a product, and complication of
the shape, it has been desired to improve performances called molding
properties such as easiness in crushing, in addition to comfortableness to
sit on. "Easiness in crushing" is referred to as "crushing property" and
meant to be easiness in operation to crush the foam by e.g. a roller for
connection of the foam released from the mold, i.e. crushing. If the
closed cell ratio of the foam is high, cracks will form on the foam at the
time of crushing, and such is unfavorable, and when the closed cell ratio
is low, crushing can easily be carried out.
With respect to a resilient polyurethane foam produced by using a polyether
polyol produced by using a double metal cyanide complex which has
conventionally been proposed as a catalyst, performances of the foam are
not adequate, and particularly crushing property of the sheet cushion is
poor, such being problematic. Accordingly, in a case of forming a sheet
cushion having a large size and a complicated shape, failure in forming
will frequently arise, such being problematic. Further, physical
properties of a polyurethane elastomer produced by using the polyether
polyol produced by using said double metal cyanide complex catalyst is not
adequate.
DISCLOSURE OF THE INVENTION
The present invention has been made to overcome the above-described
problems, and provides the following.
A catalyst for alkylene oxide ring-opening polymerization, which comprises
a double metal cyanide complex catalyst having, as an organic ligand, a
compound represented by the following formula (1) [hereafter sometimes
referred to as compound (X)] coordinated thereto:
R.sup.1 --C (CH.sub.3).sub.2 (OR.sup.0).sub.n OH (1)
wherein R.sup.1 is a methyl group or an ethyl group, R.sup.0 is an ethylene
group or a group having a hydrogen atom in said ethylene group substituted
by a methyl group or an ethyl group, and n is an integer of from 1 to 3.
A catalyst for alkylene oxide ring-opening polymerization, which comprises
a double metal cyanide complex having, as organic ligands, the
above-mentioned compound (X) and another compound, coordinated thereto.
A method for producing a double metal cyanide complex, which comprises
having an organic ligand coordinated to a reaction product obtained by
reacting a metal halide with an alkali metal cyanometalate, in an aqueous
medium, wherein the above-mentioned compound (X) is used as the organic
ligand.
A method for producing a double metal cyanide complex, which comprises
having organic ligands coordinated to a reaction product obtained by
reacting a metal halide with an alkali metal cyanometalate, in an aqueous
medium, wherein the above-mentioned compound (X) and another compound are
used together as the organic ligands.
A method for producing a polyether monol, which comprises subjecting
alkylene oxides including an alkylene oxide having a carbon number of at
least 3, to ring-opening polymerization with a monohydroxy compound as an
initiator in the presence of the above-mentioned catalyst for alkylene
oxide ring-opening polymerization.
A method for producing a polyether monol, which comprises subjecting
alkylene oxides including an alkylene oxide having a carbon number of at
least 3, to ring-opening polymerization with a monohydroxide compound as
an initiator in the presence of the above-mentioned catalyst for alkylene
oxide ring-opening polymerization, and then subjecting ethylene oxide to
ring-opening polymerization in the presence of an alkali catalyst.
A method for producing a polyether polyol, which comprises subjecting
alkylene oxide including an alkylene oxide having a carbon number of at
least 3, to ring-opening polymerization with a polyhydroxy compound having
at least 2 hydroxyl groups as an initiator in the presence of the
above-mentioned catalyst for alkylene oxide ring-opening polymerization.
A method for producing a polyether polyol, which comprises subjecting
alkylene oxides including an alkylene oxide having a carbon number of at
least 3, to ring-opening polymerization with a polyhydroxy compound having
at least 2 hydroxyl groups as an initiator in the presence of the
above-mentioned catalyst for alkylene oxide ring-opening polymerization,
and then subjecting ethylene oxide to ring-opening polymerization in the
presence of an alkali catalyst.
A method for producing a polyurethane compound, which comprises reacting
the polyether polyol produced by the above-mentioned production method
with an isocyanate group-containing low molecular weight compound.
A method for producing a polyurethane foam, which comprises reacting the
polyether polyol produced by the above-mentioned production method with an
isocyanate group-containing low molecular weight compound in the presence
of a foaming agent.
A method for producing a resilient polyurethane foam, which comprises
subjecting alkylene oxides including an alkylene oxide having a carbon
number of at least 3, to ring-opening polymerization with a polyhydroxy
compound having from 2 to 8 hydroxyl groups as an initiator in the
presence of the above-mentioned catalyst for alkylene oxide ring-opening
polymerization, and then reacting a polyether polyol having from 2 to 8
hydroxyl groups, a hydroxyl number of from 5 to 38 mgKOH/g and an
oxyethylene group content of from 5 to 30 wt % and obtained by
ring-opening polymerization of ethylene oxide in the presence of an alkali
catalyst, with an isocyanate group-containing low molecular weight
compound in the presence of a foaming agent.
A method for producing a polyurethane elastomer, which comprises reacting
an isocyanate group-terminated urethane prepolymer obtained by reacting a
first polyether polyol with an isocyanate group-containing low molecular
weight compound, with a curing agent containing a second polyether polyol,
wherein at least one of the first polyether polyol and the second
polyether polyol is the polyether polyol produced by the above-mentioned
production method.
A method for producing a polyurethane elastomer, which comprises reacting
an isocyanate group-terminated urethane prepolymer obtained by reacting
the polyether polyol produced by the above-mentioned production method
with an isocyanate group-containing low molecular weight compound, with a
curing agent containing an active hydrogen compound other than a polyether
polyol as the main component and containing no polyether polyol.
BEST MODE FOR CARRYING OUT THE INVENTION
The double metal cyanide complex which is the catalyst for alkylene oxide
ring-opening polymerization of the present invention, can be produced by
having an organic ligand coordinated to a reaction product obtained by
reacting a metal halide with an alkali metal cyanometalate, in an aqueous
medium.
As the metal for the metal halide to be used in the present invention, it
is preferred to use at least one member selected from the group consisting
of Zn(II), Fe(II), Fe(III), Co(II), Ni(II), Mo(IV), Mo(VI), Al(III), V(V),
Sr(II), W(IV), W(VI), Mn(II), Cr(III), Cu(II), Sn(II) and Pb(II).
Particularly preferred is Zn(II) or Fe(II).
The metal halide is used preferably as an aqueous metal halide solution.
The concentration of the aqueous metal halide solution is preferably at
least 0.1 g/cc, particularly preferably at least 0.5 g/cc. Further, it is
preferably at most the saturation concentration.
At the concentration region less than the above-mentioned predetermined
concentration, a double metal cyanide complex having a high
crystallizability will be obtained, and catalytic activity will decrease.
Further, if the reaction is carried out under a condition exceeding the
saturation concentration, mixture state of the solution will be
non-uniform, and a double metal cyanide complex having a low catalytic
activity will be obtained.
As the metal constituting the cyanometalate in the alkali metal
cyanometalate, it is preferred to use at least one member selected from
the group consisting of Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III),
Mn(II), Mn(III), Ni(II), V(IV) and V(V). Particularly preferred is Co(III)
or Fe(III).
The alkali metal cyanometalate is used preferably as an aqueous alkali
metal cyanometalate solution. The concentration of the aqueous alkali
metal cyanometalate solution is preferably at most 0.5 g/cc, particularly
preferably at most 0.2 g/cc. Further, it is preferably at least 0.02 g/cc.
If the reaction is carried out under a condition exceeding the
predetermined concentration, the portion of the aqueous metal halide
solution, to which the aqueous alkali metal cyanometalate solution is
dropwise added, will be partially an alkali metal cyanometalate excessive
region, and a similar effect to the above-mentioned case where the
concentration of the metal halide is low, whereby catalytic activity will
decrease. Further, if the reaction is carried out under a condition of a
low concentration, catalytic activity will decrease.
The reaction of the metal halide with the alkali metal cyanometalate is
carried out in an aqueous medium. Said reaction is carried out preferably
by mixing the aqueous metal halide solution with.the aqueous alkali metal
cyanometalate solution, particularly preferably by dropwise adding the
aqueous alkali metal cyanometalate solution to the aqueous metal halide
solution.
The reaction temperature is preferably at least 0.degree. C., particularly
preferably at least 30.degree. C. Further, it is preferably lower than
70.degree. C., particularly preferably lower than 50.degree. C. If the
reaction is carried out at a high temperature region, a double metal
cyanide complex having a high crystallizability will be synthesized, and
further, an organic ligand can not coordinate thereto, whereby no
catalytic activity will be obtained. Further, at a low temperature region,
the reaction for synthesis of the double metal cyanide complex will be
inadequate, and catalytic activity will decrease.
As the reaction product thus obtained, Zn.sub.3 [Fe(CN).sub.6 ].sub.2,
Zn.sub.3 [Co(CN).sub.6 ].sub.2, Fe[Fe(CN).sub.6 ] or Fe[CO(CN).sub.6 ]
may, for example, be mentioned, and Zn.sub.3 [Co(CN).sub.6 ].sub.2 i.e.
zinc hexacyanocobaltate is particularly preferred. The double metal
cyanide complex of the present invention is preferably a double metal
cyanide complex having an a organic ligand coordinated to zinc
hexacyanocobaltate.
Then, to the above-mentioned reaction product, an organic ligand is
coordinated. In the present invention, as the organic ligand, a compound
represented by the following formula (1) is used:.
R.sup.1 --C(CH.sub.3).sub.2 (OR.sup.0).sub.n OH (1)
wherein R.sup.1 is a methyl group or an ethyl group, R.sup.0 is an ethylene
group or a group having a hydrogen atom in said ethylene group substituted
by a methyl group or an ethyl group, and n is an integer of from 1 to 3.
R.sup.0 is particularly preferably a group selected from an ethylene group,
a propylene group, an ethylethylene group, a 1,2-dimethylethylene group
and a 1,1-dimethylethylene group.
As the compound (X), specifically the following compounds are preferred.
In a case where n is 1:
Ethylene glycol mono-tert-butyl ether having a methyl group as R.sup.1 and
an ethylene group as R.sup.0, propylene glycol mono-tert-butyl ether
having a methyl group as R.sup.1 and a propylene group as R.sup.0,
1,2-butylene glycol mono-tert-butyl ether having a methyl group as R.sup.1
and an ethylethylene group (1,2-butylene group) as R.sup.0, isobutylene
glycol mono-tert-butyl ether having a methyl group as R.sup.1 and a
1,1-dimethylethylene group (isobutylene group as R.sup.0, ethylene glycol
mono-tert-pentyl ether having an ethyl group as R.sup.1 and an ethylene
group as R.sup.0, propylene glycol mono-tert-pentyl ether having an ethyl
group as R.sup.1 and a propylene group as R.sup.0, 1,2-butylene glycol
mono-tert-pentyl ether having an ethyl group as R.sup.1 and an
ethylethylene group as R.sup.0, and isobutylene glycol mono-tert-pentyl
ether having an ethyl group as R.sup.1 and a 1,1-dimethylethylene group as
R.sup.0.
Particularly preferred are ethylene glycol mono-tert-butyl ether, propylene
glycol mono-tert-butyl ether, ethylene glycol mono-tert-pentyl ether and
propylene glycol mono-tert-pentyl ether.
In a case where n is 2:
Diethylene glycol mono-tert-butyl ether having a methyl group as R.sup.1
and an ethylene group as R.sup.0, dipropylene glycol mono-tert-butyl ether
having a methyl group as R.sup.1 and a propylene group as R.sup.0,
di-1,2-butylene glycol mono-tert-butyl ether having a methyl group as
R.sup.1 and an ethylethylene group as R.sup.0, diisobutylene glycol
mono-tert-butyl ether having a methyl group as R.sup.1 and a
1,1-dimethylethylene group as R.sup.0, diethylene glycol mono-tert-pentyl
ether having an ethyl group as R.sup.1 and an ethylene group as R.sup.0,
dipropylene glycol mono-tert-pentyl ether having an ethyl group as R.sup.1
and a propylene group as R.sup.0, di-1,2-butylene glycol mono-tert-pentyl
ether having an ethyl group as R.sup.1 and an ethylethylene group as
R.sup.0, and diisobutylene glycol mono-tert-pentyl ether having an ethyl
group as R.sup.1 and a 1,1-dimethylethylene group as R.sup.0.
Particularly preferred are diethylene glycol mono-tert-butyl ether and
diethylene glycol mono-tert-pentyl ether.
In a case where n is 3:
Triethylene glycol mono-tert-butyl ether having a methyl group as R.sup.1
and an ethylene group as R .sup.0, tripropylene glycol mono-tert-butyl
ether having a methyl group as R.sup.1 and a propylene group as R.sup.0,
tri-1,2-butylene glycol mono-tert-butyl ether having a methyl group as
R.sup.1 and an ethylethylene group as R.sup.0, truisobutylene glycol
mono-tert-butyl ether having a methyl group as R.sup.1 and a
1,1-dimethylethylene group as R.sup.0, triethylene glycol mono-tert-pentyl
ether having an ethyl group as R.sup.1 and an ethylene group as R.sup.0,
tripropylene glycol mono-tert-pentyl ether having an ethyl group as
R.sup.1 and a propylene group as R.sup.0, tri-1,2-butylene glycol
mono-tert-pentyl ether having an ethyl group as R.sup.1 and an
ethylethylene group as R.sup.0, and triisobutylene glycol mono-tert-pentyl
ether having an ethyl group as R.sup.1 and a 1,1-dimethylethylene group as
R.sup.0.
Particularly preferred are triethylene glycol mono-tert-butyl ether and
triethylene glycol mono-tert-pentyl ether.
As the compound (X), a compound wherein n is 1 is particularly preferred,
and a compound wherein R.sup.1 is a methyl group is particularly
preferred. Further, as the compound (X), two or more compounds may be used
together.
In a case where the compound (X) and another compound are used together as
the organic ligand, the compound to be used together is preferably one or
more compounds selected from the group consisting of tert-butyl alcohol,
n-butyl alcohol, isobutyl alcohol, tert-pentyl alcohol, isopentyl alcohol,
N,N-dimethylacetamide, glyme (ethylene glycol dimethyl ether), diglyme
(diethylene glycol dimethyl ether), triglyme (triethylene glycol dimethyl
ether), isopropyl alcohol and dioxane. The dioxane may be 1,4-dioxane or
1,3-dioxane, and 1,4-dioxane is preferred. As the compound to be used
together, particularly preferred is tert-butyl alcohol, tert-pentyl
alcohol or glyme. Most preferred is tert-butyl alcohol
In the present invention, the double metal cyanide complex is produced
preferably by subjecting the reaction product obtained by reacting the
metal halide with the alkali metal cyanometalate, to aging in one kind of
organic ligand or a mixed organic ligands of at least two kinds among the
above-mentioned organic ligands.
In the case of using the compound (X) and said another compound together as
the organic ligands, it is preferred to subject the reaction product
obtained by reacting the metal halide with the alkali metal cyanometalate,
to aging in the mixed ligands with a weight ratio of the compound (X) to
said another compound of from 1/99 to 99/1.
As the method of aging, a method to dropwise add one type of organic ligand
or a mixed organic ligands of at least two kinds, to a solution containing
the above-mentioned reaction product, followed by stirring, may, for
example, be mentioned. The aging temperature is preferably at least the
reaction temperature, particularly preferably at least 30.degree. C., and
preferably lower than 125.degree. C., particularly preferably at most
80.degree. C. The aging time is preferably at least 15 minutes. Although
the upper bound of the aging time is not particularly limited, it is
industrially preferred to limit the upper bound to a level of from 2 to 3
hours.
By subjecting the slurry obtained by the above-mentioned aging to
filtration, a cake containing the double metal cyanide complex will be
obtained. Further, as the case requires, it is preferred to add to said
cake a compound selected from the group consisting of water, the organic
ligand to be used for the synthesis and an organic ligand other than the
organic ligand to be used for the synthesis, for washing, followed by
further filtration (washing operation). Said washing operation may be
repeated several times. Unless the organic ligand used for washing has a
particularly high coordination power as compared with the organic ligand
already coordinated to the catalyst, part or all the organic ligand
already coordinated is seldom substituted by the organic ligand used for
washing.
The obtained cake containing the double metal cyanide complex is dried to
obtain the double metal cyanide complex. Drying is carried out by e.g. a
drying method by heating, a drying method under vacuum, or a method of
mixing with a hardly volatile liquid and then removing water content and
the volatile organic ligand. The drying is carried out at a temperature of
preferably from 0 to 150.degree. C., particularly preferably at most
90.degree. C. This is to prevent volatilization of the entire coordinated
organic solvent and water.
The present invention provides a catalyst for alkylene oxide ring-opening
polymerization, which comprises the double metal cyanide complex produced
by the above-mentioned method.
The present invention further provides a method for producing a polyether
monol or a polyether polyol, which comprises using said catalyst for
alkylene oxide ring-opening polymerization comprising the double metal
cyanide complex produced by the above-mentioned method. Namely, the
present invention provides a method for producing a polyether monol, which
comprises subjecting alkylene oxides including an alkylene oxide having a
carbon number of at least 3, to ring-opening polymerization with a
monohydroxy compound as an initiator in the presence of the
above-mentioned catalyst for alkylene oxide ring-opening polymerization of
the present invention; and a method for producing a polyether polyol,
which comprises subjecting alkylene oxides including an alkylene oxide
having a carbon number of at least 3, to ring-opening polymerization with
a polyhydroxy compound having at least 2 hydroxyl groups as an initiator
in the presence of the above-mentioned catalyst for alkylene oxide
ring-opening polymerization of the present invention.
The alkylene oxides include an alkylene oxide having a carbon number of at
least 3. As the alkylene oxide having a carbon number of at least 3,
propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide or epichlorohydrin
may, for example, be mentioned. Two or more of these may be used together,
and in such a case, they may be mixed with each other for reaction, or
they may be successively subjected to reaction.
In the case of using the catalyst for alkylene oxide ring-opening
polymerization of the present invention, ethylene oxide as the alkylene
oxide having a carbon number of 2 alone hardly undergoes reaction, and it
may undergo reaction by mixing with an alkylene oxide having a carbon
number of at least 3 followed by addition to the reaction system.
Particularly preferred alkylene oxide is propylene oxide or a combination
of propylene oxide with ethylene oxide.
Further, as mentioned hereinafter, in the case of producing a resilient
polyurethane foam by using the polyether polyol of the present invention,
the polyether polyol preferably has oxyethylene groups at the terminals,
and the content of said terminal oxyethylene group is particularly
preferably from 5 to 30 wt %.
The polyether monol or the polyether polyol having oxyethylene groups at
the terminals can be produced by subjecting alkylene oxides including an
alkylene oxide having a carbon number of at least 3, to ring-opening
polymerization with an initiator by using the above-mentioned catalyst for
alkylene oxide ring-opening polymerization of the present invention, and
then subjecting ethylene oxide to reaction by using an alkali catalyst.
Namely, the present invention provides a method for producing a polyether
monol, which comprises subjecting alkylene oxides including an alkylene
oxide having a carbon number of at least 3, to ring-opening polymerization
with a monohydroxy compound as an initiator in the presence of the
above-mentioned catalyst for alkylene oxide ring-opening polymerization,
and then subjecting ethylene oxide to ring-opening polymerization in the
presence of an alkali catalyst; and a method for producing a polyether
polyol, which comprises subjecting alkylene oxides including an alkylene
oxide having a carbon number of at least 3, to ring-opening polymerization
with a polyhydroxy compound having at least 2 hydroxyl groups as an
initiator in the presence of the above-mentioned catalyst for alkylene
oxide ring-opening polymerization, and then subjecting ethylene oxide to
ring-opening polymerization in the presence of an alkali catalyst.
As the alkali catalyst, an alkali metal such as sodium or potassium, an
alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, or
an alkali metal alkoxide such as sodium alkoxide or potassium alkoxide,
may, for example, be mentioned.
As specific examples of the monohydroxy compound and the polyhydroxy
compound having at least 2 hydroxyl groups to be used as the initiator,
the following are mentioned. However, such compounds are not limited
thereto.
Methanol, isopropyl alcohol, n-butyl alcohol, 2-ethylhexanol,
1-octadecanol, allyl alcohol, oleyl alcohol, ethylene glycol, diethylene
glycol, propylene glycol, dipropylene glycol, glycerol,
trimethylolpropane, pentaerythritol, diglycerol, sorbitol, dextrose,
methyl glucoside, sucrose, bisphenol A, phenol, diethanolamine,
triethanolamine and the like. Further, an alkylene oxide addition product
of such an initiator may also be used as the initiator. Further, an
alkylene oxide addition product of a polyamine such as a monoamine or a
diamine may be used. As mentioned hereinafter, in the case of producing a
resilient polyurethane foam, it is preferred to use a polyhydroxy compound
having from 2 to 8 hydroxyl groups.
The polyether monol or the polyether polyol can be produced by adding the
catalyst for alkylene oxide ring-opening polymerization of the present
invention to the hydroxy compound as the initiator, and gradually adding
the alkylene oxide thereto to carry out the reaction. The amount of said
catalyst is not particularly limited, and suitably at a level of from 1 to
5000 ppm, more preferably from 100 to 2000 ppm, based on the hydroxy
compound to be used. The reaction temperature is preferably from 30 to
180.degree. C., more preferably from 90 to 130.degree. C. As the
introduction of said catalyst to the reaction system, it may be initially
introduced all at once, or it may be successively introduced in
installments. The polyether polyol after the completion of the reaction
may be used directly, and preferably the catalyst is removed.
The hydroxyl number of the obtained polyether monol or polyether polyol is
not particularly limited, and the hydroxyl number is preferably from 5 to
70 mgKOH/g.
The polyether monol and the polyether monol obtained by the above-mentioned
method, may be used for e.g. a surface active agent and a lubricant.
Further, the polyether polyol obtained by the above-mentioned method may
be used as a starting material for a polyurethane.
The present invention provides a method for producing a polyurethane
compound, which comprises reacting a polyether polyol obtained by the
above-mentioned method with an isocyanate group-containing low molecular
weight compound.
More preferred is a method for producing a polyurethane foam, which
comprises reacting the polyether polyol obtained by the above-mentioned
production method with an isocyanate group-containing low molecular weight
compound in the presence of a foaming agent. As the polyurethane foam, a
resilient polyurethane foam is particularly preferred.
To obtain a resilient polyurethane foam, it is preferred to use a polyether
polyol obtained by the above-mentioned production method and satisfying
the following conditions (a) to (c).
(a) The number of hydroxyl group is from 2 to 8, (b) the hydroxyl number is
from 5 to 38 mgKOH/g, and (c) the oxyethylene group content is from 5 to
30 wt %.
Namely, the present invention provides a method for producing a resilient
polyurethane foam, which comprises subjecting alkylene oxides including an
alkylene oxide having a carbon number of at least 3, to ring-opening
polymerization with a polyhydroxy compound having from 2 to 8 hydroxyl
groups as an initiator in the presence of the above-mentioned catalyst for
alkylene oxide ring-opening polymerization, and then reacting a polyether
polyol having from 2 to 8 hydroxyl groups, a hydroxyl number of from 5 to
38 mgKOH/g and an oxyethylene group content of from 5 to 30 wt % and
obtained by ring-opening polymerization of ethylene oxide in the presence
of an alkali catalyst, with an isocyanate group-containing low molecular
weight compound in the presence of a foaming agent.
The polyether polyol produced by using the catalyst for alkylene oxide
ring-opening polymerization of the present invention, has an unsaturation
of from 0.005 to 0.02 meq/g with a hydroxyl number of 34, for example.
When a resilient polyurethane foam is produced by using this polyether
polyol, the above-mentioned problems such as decrease in hardness,
decrease in ball rebound, deterioration in compression set, and decrease
in curing property at the time of forming a foam, will be minimized, and
particularly the crushing property of a sheet cushion will significantly
be excellent. Accordingly, crushing will easily be carried out even in a
case of producing a sheet cushion having a large size and a complicated
shape.
The above-mentioned polyether polyol can be used also as a
polymer-dispersed polyether polyol containing fine polymer particles.
The polymer-dispersed polyether polyol is a dispersion of fine polymer
particles stably dispersed in polyoxyalkylene polyol matrix. As the
polymer, an addition polymerization type polymer or a condensation
polymerization type polymer may be mentioned.
The fine polymer particles in the polymer-dispersed polyol comprises an
addition polymerization type polymer such as a homopolymer or a copolymer
of acrylonitrile, styrene, methacrylate, acrylate or another vinyl
monomer, or a condensation polymerization type polymer such as polyester,
polyurea, polyurethane or melamine resin. Due to presence of the fine
polymer particles, the hydroxyl number of the entire polymer-dispersed
polyol is usually low as compared with the hydroxyl number of the polyol
as matrix.
The content of the fine polymer particles in the polyol is usually
preferably at most 50 wt %. It is not particularly necessary that the
amount of the fine polymer particles is high, and there will be no problem
except in view of economical feasibility even if it is too high. It is
preferably from 3 to 35 wt % in many cases. Although the presence of the
fine polymer particles in the polyol is not essential, the presence is
effective to improve physical properties of the foam such as hardness or
air flow.
Further, in addition to the above-mentioned polyether polyol obtained by
the production method of the present invention, another polyether polyol
may be used together. For example, a polyether polyol, a polyester polyol
or a hydroxyl group-containing olefin type polymer, produced by using a
catalyst comprising a double metal cyanide complex other than the double
metal cyanide complex of the present invention, a general-purpose alkali
catalyst such as an alkali metal including sodium and potassium, an alkali
metal hydroxide including sodium hydroxide and potassium hydroxide, or an
alkali metal alkoxide including sodium alkoxide and potassium alkoxide, or
a cesium catalyst such as cesium hydroxide, may be mentioned.
Further, a low molecular weight compound called a chain-extender or a
cross-linking agent may be used together. Specifically, a low molecular
weight polyhydric alcohol or a polyhydric amine may, for example, be
mentioned.
As the isocyanate group-containing low molecular weight compound to be used
in the present invention, preferred is a low molecular weight
polyisocyanate having at least 2 isocyanate groups. As the low molecular
weight polyisocyanate, an aromatic, alicyclic or aliphatic polyisocyanate,
a mixture of at least two of them, and a modified polyisocyanate obtained
by modification thereof may, for example, be mentioned.
Specifically, a polyisocyanate such as tolylene diisocyanate (TDI),
diphenylmethane diisocyanate (MDI), polymethylene polyphenyl isocyanate
(popular name: crude MDI), xylylene diisocyanate (XDI), isophorone
diisocyanate (IPDI) or hexamethylene diisocyanate (HMDI), or its
prepolymer type modified product, nurate modified product, urea modified
product or carbodiimide modified product may, for example, be mentioned.
As the foaming agent, it is preferred to use at least one foaming agent
selected from water and an inert gas. As the inert gas, specifically,
water or nitrogen may, for example, be mentioned. The amount of such a
foaming agent is not particularly limited, and in the case of using water
alone, the amount is suitably at most 10 parts by weight, particularly
from 0.1 to 8 parts by weight, based on 100 parts by weight of the
polyether polyol. Another foaming agent may be used in a suitable amount
depending upon demands such as foam magnification.
In the case of reacting the polyether polyol with the isocyanate
group-containing low molecular weight compound, it is usually required to
use a catalyst. An amine compound or an organic metal compound may, for
example, be used. Further, a multiple catalyst for reaction of isocyanate
groups in e.g. a metal carboxylate may be used depending upon the purpose.
As the amine compound, triethylenediamine,
bis[(2-dimethylamino)ethyl]ether, N,N-dimethylethanolamine,
trimethylaminoethylethanolamine or a compound having two molecules of
ethylene oxide added to N,N-dimethylethanolamine [(CH.sub.3).sub.2
NCH.sub.2 CH.sub.2 (OCH.sub.2 CH.sub.2)OH] may, for example, be mentioned.
The amount of such an amine compound is preferably at most 1.0 part by
weight, particularly preferably from 0.05 to 1.0 part by weight, based on
100 parts by weight of the polyether polyol.
As the organic metal compound, an organotin compound, Inn an organic
bismuth compound, an organic lead compound or an organic zinc compound
may, for example, be mentioned, and specifically, di-n-butyltin oxide,
di-n-butyltin dilaurate, di-n-butyltin, di-n-butyltin diacetate,
di-n-octyltin oxide, di-n-octyltin dilaurate, monobutyltin trichloride,
di-n-butyltin dialkylmercaptan or di-n-octyltin dialkylmercaptan may, for
example, be mentioned. The amount of such an organic metal compound is
preferably at most 1.0 part by weight based on 100 parts by weight of the
polyether polyol.
Further, in many cases, a foaming stabilizer to form excellent foams may be
used. As the foaming stabilizer, a silicone type foaming stabilizer or a
fluorine-containing compound type foaming stabilizer may, for example, be
mentioned. As a compounding agent which may optionally be used, a filler,
a stabilizer, a coloring agent, a flame retardant or an antifoaming agent
may, for example, be mentioned.
The molding of the resilient polyurethane foam is carried out preferably by
a method of directly injecting a reactive mixture into a closed mold by
using a low-pressure foaming machine or a high-pressure foaming machine
(i.e. reaction injection molding), or by a method of spreading a reactive
mixture into a mold in an open state. The high-pressure foaming machine is
preferably a conventional type of mixing two liquids, one of which is Dok
san isocyanate group-containing low molecular weight compound, and t | | |
