Note: Descriptions are shown in the official language in which they were submitted.
~2:3~
Mo3250
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NOVEL ISOCYANATE BLENDS
_ _ . _ _
BACKGROUND OF THE INVENTION
_. _
Liquid, modified isocyanates produced by reacting
methylenebis(phenyl isocyanate) with from about 0.1 to about 0.3
mole of a 134 to 700 molecular weight poly-1,2-propylene ether
glycol are known (see, e.g., U.S. Patent 3,644,457). Also known
are liquid, carbodiimide group modified methylenebis(phenyl
isocyanates) (seeS e.g., U.S. Patents 3,384,653 and 4,154,752).
Blends of liquid, carbodiimide group modified
methylenebis(phenyl isocyanates) with various liquid prepolymers
of methylenebis(phenyl isocyanate) are also described in the art
(see, e.g., U.S. Patents 4,031,026, 4,065,410 and 4,321,333).
Additionally, an isocyanate having an isocyanate group content of
about l9Yo by weight and prepared by reacting (i) methylenebis
5 (phenyl isocyanate), (ii) a carbodiimide group modified
methylenebis(phenyl isocyanate) having an isocyanate group
content of about 29~ by weight and (iii) a 2000 molecular weight
polyester diol is commercially available.
Systems are commercially available which are used in
the production of polyurethane shoe soles. In general, these
systems comprise a polyether diol, a polyether triol, a chain
extender (such as 1,4-butane diol or ethylene glycol), blowing
agent, catalyst and surfactant. The use of so-called filled
polyols in such systems is described in U.S. Patents 4~448,903
and 4,477,~02. Although these systems have met with some
commercial success, when attempts are made to produce relatively
low density parts (such as, e.g., densities in the range of from
0.30 to 0.45 g/cc), low temperature flex fatigue resistance is
generally not satisfactory.
DESCRIPTION OF THE INVENlION
The present invention is directed to the discovery of a
novel isocyanate blend which when used in shoe sole systems of
the type mentioned above give marked improvement in low
temperature flex resistance while substantially maintaining the
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excellent physical properties normally associated with such
systems. More particularly, the present invention is directed to
an isocyanate blend of two known isocyanates. More specifically,
5 the present invention is directed to an isocyanate blend having
an isocyanate group content of from about 16 to about 25% by
weight and consisting essentially of:
A) a modified isocyanate having an isocyanate group content
of from about 18 to about 25% by weight and prepared by
reacting 1 mole of methylenebis(phenyl isocyanate) with
from about 0.1 to about 0.3 moles of a 134 to 700
molecular weight poly-1,2-propylene ether glycol, and
B) an isocyanate having an isocyanate group content of from
about 16 to about 22% by weight and prepared by
reacting:
(i) from about 40 to about 60 parts by weight
of methylenebis(phenyl isocyanate),
(ii) from 0 to about 10 parts by weight of a
carbodiimide group modified methylenebis-
(phenyl isocyanate) having an isocyanate group
content of from about 24 to about 33% by weight,
and
(iii) from about 30 to about 50 parts by weight
of a polyester diol having a molecular
weight of from about 1000 to about 3000 ,
with the amounts of (i), (ii) and (iii)
totalling 100 parts by weight,
the weight ratio of A~ to B) being from 10:1
to 1:10, and preferably from 3:1 to 1: 3, and
most preferably from 3:1 to 1:1.
As used herein, the term, methylenebis(phenyl
isocyanate), is intended to include the 2,2'-isomer, the
2,4'-isomer, the 4,4'-isomer, and mixtures thereof.
As noted earlier, the individual components making up
35 the isocyanate blend of the invention are known. Component A) is
a modified isocyanate having an isocyanate group content of from
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about 18 to about 25 % by weight, and preferably from about 21 to
about 24 % by weight, prepared by reacting 1 mole of methylene-
bis(phenyl isocyanate) with from about 0.1 to about 0.3 moles of
a 134 to 700 molecular weight poly-1,2-propylene ether glycol.
5 The most preferred modified isocyanate has an isocyanate group
content of about 23% by weight and is prepared from the
4,4'-isomer of methylenebis(phenyl isocyanate) and tripropylene
glycol. One such isocyanate which is commercially available is
Mondur PF, sold by Mobay Corporation. The preparation of
10 modified isocyanates which are useful as component A) is
described in U.S. Patent 3,644,457, the disclosure of which is
herein incorporated by reference.
Component B) of the present invention is an isocyanate
having an isocyanate group content of from about 16 to about 22%
15 by weight, and preferably from about 18 to about 20% by weight,
prepared by reacting:
(i) from about 40 to about 60, and preferably from
about 50 to about 60 parts by weight of
methylenebis(phenyl isocyanate), -
(ii) from O to about 10, and preferably from about 4
to about 8 parts by weight of a carbodiimide
group modified methylenebis(phenyl isocyanate)
having an isocyanate group content of from about
24 to about 33, and preferably from about 28 to
about 31% by weight, and
(iii) from about 30 to about 50, and preferably from
about 35 to about 41 parts by weight of a
polyester diol having a molecular weight of from
about 1000 to about 3000, and preferably from
about 1500 to about 2500, with the amounts of
(i), (ii) and (iii) totalling 100 parts by
weight.
The carbodiimide group modified methylenebis(phenyl
isocyanates) used to prepare component B) are known in the art.
35 The preparation of such carbodiimide modified isocyanates is
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described in U.S. Patents 3,384,653 and 4,154,752, the
disclosures of which are herein incorporated by reference.
The polyesters useful in preparing component B) are
also generally known in the polyurethane art. Typically, such
5 polyesters are reaction products of dihydric alcohols and dibasic
carboxylic acids. Instead of the free acid, the corresponding
anhydride may be used. The acids may be aliphatic, cyclo-
aliphatic, aromatic or heterocyclic. Useful acids include
succinic acid, adipic acid, suberic acid, azelaic acid, sebacic
10 acid, phthalic acid, isophthalic acid and the like. Useful
dihydric alcohols include ethylene glycol, 1,2- and 1,3-propylene
glycol, 1,4- and 2,3-butane diol, 1,6-hexane diol, 1,8-octane
diol, neopentyl glycol, cyclohexanedimethanol and the like.
The most preferred component B~ is an isocyanate having
15 an isocyanate group content of about 19% by weight prepared by
reacting:
(i) 56 parts by weight of the 4,4'-isomer of
methylenebis(phenyl isocyanate),
(ii) 6 parts by weight of a carbodiimide modified
methylenebis(phenyl isocyanate) having an isocyanate
group content of 29.3% and a viscosity at 25C of
less than 100 mPa.s (and commercially available from
Mobay Corporation as Mondur CD), and
(iii) 38 parts by weight of a 2000 molecular weight
polyester diol prepared by reacting adipic acid,
1,4-butane diol and ethylene glycol (ethylene glycol
to butane diol molar ratio of about 1:1).' This
preferred isocyanate component B) is commercially
available from Mobay Corporation as Mondur E-501.
The isocyanates of the present invention are useful in
the preparation of shoe soles. The isocyanates are reacted with
relatively high molecular weight polyols and chain extenders in
the presence of blowing agents and optionally, catalysts and
surfactants. It is preferred to use isocyanate reactive systems
35 of the type known and described in U.S. Patents 4,448,903 and
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4,477,602, the disclosures of which are herein incorporated by
reference.
The invention is further illustrated but is not
intended to be limited by the following examples in which all
5 parts and percentages are by weight unless otherwise specified.
~XAMPLES
Examples 1 through 6
An isocyanate reactive composition was prepared by
blending the following components:
69.26 parts by weight polyether diol having an OH
number of about 28 and prepared by reacting
propylene glycol, propylene oxide and ethylene
oxide (weight ratio of propylene to ethylene
oxide about 4:1), and containing 91% primary
hydroxyl groups;
13.80 parts by weight a dispersion having an OH number
of about 28 and consisting of a
polyhydrazodicarbonamide in a glycerin initiated
propylene oxide/ethylene oxide polyether (having
an OH number of 35) and produced by reacting
toluene diisocyanate and hydrazine in the
presence of the polyether according to U.S.
Patent 4,042,537; the dispersion has a solids
content of 20% by weight;
7.67 parts by weight 1,4-butane diol;
2.40 parts by weight Dabco HB, a catalyst
available from Air Products;
0.03 parts by weight dibutyltin dilaurate;
0.10 parts by weight L5810, a surfactant
available from Union Carbide;
0.08 parts by weight of a commercially available
polydimethylsiloxane having a viscosity of
15,500 to 19,500 cps at 25C;
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6.34 parts by weight R~ B, a stabilized
monofluorotrichloromethane available from
Pennwalt; and,
U.32 parts by weight water.
In these examples, the following isocyanates were used
either alone or in combination in the weight ratios set forth in
Table 1. The isocyanates were:
A) a modified isocyanate having an isocyanate group content
of about 23~ by weight, prepared by reacting the
4,4'isomer of methylenebis(phenyl isocyanate) with
tripropylene glycol; and
B) an isocyanate having an isocyanate group content of
about 19% by weight prepared by reacting:
(i) 56 parts by weight of the 4,4'-isomer of
methylenebis(phenyl isocyanate),
(ii) 6 parts by weight of a carbodiimide modified
methylenebis(phenyl isocyanate) having an
isocyanate group content of 29.3% and a viscosity
at 25C of less than 100 mPa.s (and commercially
available from Mobay Corporation as Mondur CD),
and
(iii) 38 parts by weight of a 2000 molecular weight
polyester diol prepared by reacting adipic acid,
1,4-butane diol and ethylene glycol (ethylene
glycol to butane diol molar ratio of about 1:1).
These examples were carried using a DESMA PSA 90/91
machine, a typical low pressure polyurethane shoe sole machine
under the following process conditions:
(a) temperatures of the isocyanate components and the
isocyanate reactive components: 77 + 3F;
(b) mold temperature: 110 + 5F;
(c) throughput:50 to 60 g/sec.
(d) isocyanate index: 98
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The liquid reaction mixture was quickly poured into a 0.25" x 6"
x 6" plaque mold, and demolded after about 3 minutes. All parts
were molded at a density of about 0.46 g/cc. Rossflex was
measured according to ASTM D-1052. The parts were also tested
5 for Shore A hardness (ASTM D-2240), tensile strength and
elongation at break(ASTM D-412), split tear (ASTM D-3574, test F)
and Die C tear (ASTM D-624).
Examples 1 and 6 are comparative examples. The results
were as reported in Table 1.
10TABLE 1
Example ISO SHORE A ROSS SPLIT DIE C
HARDNESS FLEX TEAR TEAR TENSILE ELONGATION
-20F 3 (pli) (Pli) (psi) (%)
15(cycles x10 )
_______________ _______________________________________ _____________________
1 A 49 31 23.4 82.2 425.7 390
2 A:B 49 54 20.3 88.8 380.9 350
9:1
3 A:B 48 107 23.8 77.1 310.1 340
3:1
25 4 A:B 46 190 20.6 73.3 297.4 340
1:1
A:B 35 136 19.1 51.2 163.3 210
1:9
6 B 35 126 19.1 44.2 136.0 160
Although the invention has been described in detail in
the foregoing for the purpose of illustration, it is to be
35 understood that such detail is solely for that purpose and that
variations can be made therein 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.
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