Note: Descriptions are shown in the official language in which they were submitted.
1 3 2 ~ 5 2 6 Mo30~4CIP
POLYUREA RIM SYSTEMS HAVING
IMPROVED FLOW PROPERTIE5
BACKGROUND OF THE INVENTION
Reaction injection molded (RIM) polyurethanes are well
5 known in the art and have met with substantial commercial
success. U.S. Patent 4,218,543 describes the use of relative1y
high molecular weight hydroxyl group containing materials,
certain aromatic diamines as chain extenders, and isocyanates for
the production of RIM parts.
More recently the activity in the art has been towards
; the production of polyurea RIM parts. Typically, these parts are
made from relatively high molecular weight polyethers which
contain amine groups, diamine chain extenders and isocyanates
Typical of the materials used and the technologies known in the
15 art are those described in U.S. Patents 4,774,263, 4,774,264
issued September 27, 1988, 4,396,729, 4,433,067, 4,444,910
and 4,5~0,941 -
As is known in the art, RIM parts are
generally produced from two separate streams. One stream
20 generally contains the isocyanate component, while the other
stream contains the amine-containing polyether and the amine
chain extender. One problem is that blends of certain of the
am~ne-conta~ning polyether and the amine chain extender are
generally too vlscous for use in conventional commercial RIM
25 mach~nery. An object of the present lnvention was therefore to
prov~de a mlxture of amlne-contalnlng polyether and amlne chain
extender havlng a substant~ally reduced vlscosity and thus
improved flow character~stlcs. Addltlonally, th~s lmprovement ln
flow propert~es would have to be achleved w~thout adversely
30 affect~ng the phys~cal propertles of the final RIM part.
The use of cycl~c alkylene carbonates ~n polyurethane
chemlstry ls known. U.S. Patent 3,883,466 descr~bes the use of a
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cyclic alkylene carbonate as a liquid modifier to moderate the
reaction exotherm between the hydroxy component and the
polyisocyanate in the production of a rigid, dense rapid-setting
polyurethane. U.S. Patents 4,709,002 and 4,731,427 describe the
5 use of cyclic alkylene carbonates in the production of rigid RIM
polyisocyanurate and urethane-modified polyisocyanurate parts.
These two references do not indicate why the cyclic alkylene
carbonate is used but do suggest that the carbonate can be added
to the isocyanate stream in order to reduce its viscosity.
U.S. Patents 4,000,105 and 4,154,716 describe a variety
of different liquid modifiers, including alkylene carbonates,
which can be used in the production of rigid and non-elastomeric
polyurethanes. The references do not indicate why the liquid
modifiers are added. U.S. Patent 4,530,941 suggests at column 7,
15 lines 36-52, that the modif;ers described in these two patents
can be used in the production of polyurea RIM parts.
DESCRIPTION OF THE INVENTION
The present invention is directed to a process for making
a reaction injection molded elastomer comprising injecting a
20 reaction mlxture into a mold cavity via a RIM machine with the
ratio of components being such that the isocyanate index is from
about 70 to about 130. The reaction mixture comprises
a) an organic di- and/or polyisocyanate,
b) a polyether having at least two isocyanate
reactive groups and a molecular weight of from 1800
to 12,000 in which at least 50~ of the isocyanate-
reactlve groups are primary and/or secondary amine
groups,
c) an amlne-terminated chain extender, and
d) from 2 to 20 parts by weight per 100 parts by
weight of components b) and c), of a cyclic alkylene
carbonate.
The present invention ls also directed to an isocyanate-
reactive mixture comprising
l) a polyether having at least two isocyanate-reactive
groups and a molecular weight of from 1800 to 12,000
Mo3084CIP - 2 -
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in which at least 50~ of the isocyanate reactive
groups are primary and/or secondary amine groups,
ii) an amine-terminated chain extender, and
iii) from 2 to 20 parts by weight per 100 parts by
weight of components i) and ii) of a cyclic alkylene
carbonate.
Several advantages are seen in using the alkylene
carbonates according to the present invention. The addition of
the carbonate results in a significant lowering of the viscosity
of the B-side. It is also particularly surprising that excellent
heat sag properties are attained. In general, one would have
expected that the highly polar carbonates would dissolve in the
hard block phase causing a significant decrease in the stiffness
at elevated temperatures. Furthermore, it was surprisingly found
that systems containing the alkylene carbonates were
significantly slower reacting when compared to systems containing
the preferred liquid modifiers described in U.S. Patents
4,000,105 and 4,154,716. This property is particularly desirable
because it allows for the complete filling of larger RIM parts.
The cyclic alkylene carbonates employed in the present
invention are used in an amount of from 2 to 20 parts, and
preferably 4 to 15 parts by weight, based on 100 parts by weight
of the isocyanate-reactive components. The cyclic alkylene
carbonates useful herein generally correspond to the formula:
; 25 Io J
where R can be hydrogen, methyl, ethyl, or a C3 to C10
hydrocarbon. Useful cyclic alkylene carbonates include ethylene
carbonate, propylene carbonate, butylene carbonate, styrene
carbonate, octylene carbonate, mixtures thereof, and the like.
The presently preferred carbonates are ethylene and propylene
carbonate.
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The isocyanate (component a)) used in the process of the
present invention is preferably an aromatic diisocyanate and/or
polyisocyanate, i.e., a polyisocyanate in which all of the
isocyanate groups are aromatically bound. Examples of such
5 compounds include 2,4- and/or 2,6-diisocyanatotoluene; 2,2'-,
2,4'- and/or 4,4'-diisocyanatodiphenyl methane, mixtures of the
last-mentioned isomers with their higher homologues (such as are
obtained from the known reaction of the phosgenation of
aniline/formaldehyde condensates); compounds containing urethane
10 groups obtained as products of reaction of the above-mentioned
di- and/or polyisocyanates with subequivalent quantities of
polyhydroxyl compounds having molecular weights of from 62 to
10,000, (e.g. ethylene glycol, trimethylol propane, propylene
glycol, dipropylene glycol or polypropylene glycols, and
15 polyester glycols within the above-mentioned molecular weight
range) di- andtor polyisocyanates modified by the partial
carbodiimidization of the isocyanate groups of the above-
mentioned di- and/or polyisocyanates; methyl-substituted
diisocyanates of the diphenyl methane series or mixtures thereof
20 (for example, those described in European Specification No.
0,024,665); or mixtures of such aromatic di- and polyisocyanates.
Included among the preferred isocyanates are the
derivatives of 4,4'-diisocyanatodiphenyl methane which are liquid
at room temperaturé. Specific examples of such compounds are
25 polyisocyanates containing urethane groups obtainable according
to German Patent 1,618,380 (U.S. 3,644,457) by reacttng 1 mol of
4,4'-diisocyanatodtphenyl methane with from 0.05-0.3 mol of low
molecular weight dtols or triols, (preferably polypropylene
glycols having molecular weights below 700); diisocyanates based
30 on 4,4'-diisocyanatodiphenyl methane conta~n~ng carbod~imide
and/or urethane ~mine groups, such as those dtsclosed tn U.S.
Patents 3,152,162; 3,384,653 and ~,44~256~ German Offenlegungs-
schrtft No. 2,537,685 and u-s- Patent 4,154,752 i~sued May 15,
1979. Also included among the preferred polyiso-
35 cyanates are the correspond~ng mod~fted products based on
mtxtures of 2,4'- and 4,4'-dt~socyanatodtphenyl methane or
Mo3084CIP - 4 -
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mixtures of the above-described modified 4,4'-diisocyanato-
diphenyl methanes with minor quantities of higher than
difunctional polyisocyanates of the diphenyl methane series.
Such polyisocyanates are described in German Offenlegungsschrift
5 2,624,526. The preferred polyisocyanate mixtures of the diphenyl
methane series are liquid at room temperature and have optionally
been chemically modified as described above, with an average
isocyanate functionality of from 2 to 2.2 (preferably 2)
containing 4,4'-diisocyanatodiphenyl methane as the main
10 component (amounting to more than 50 wt.%)
The polyethers used (as component b)) in the present
invention contain at least two isocyanate reactive groups in end
positions and have an average molecular weight (calculated from
the functionality and the isocyanate reactive group content) of
15 from 1800 to 12,000, preferably from 2000 to 8000. At least 50
equivalent percent (and preferably from 80-100 equivalent
percent) of the isocyanate reactive end groups are primary and/or
secondary (preferably primary) aromatically or aliphatically
bound amino groups with the remainder being primary and/or
20 secondary aliphatically bound hydroxyl groups. When polyether
mixtures are used, individual components of the mixture may have
a molecular weight below 1800 (for example between 500 and 1800),
provided that the average molecular weight of the mixture is
withln the range of 1800 to 12,000. The use of such mixtures in
~ 25 which individual components have a molecular weight below 1800
; is, however, not preferred.
Compounds containing amlno end groups may also be
attached to the polyether chain by urethane or ester groups.
These "amino polyethers" may be prepared by known methods. One
30 such method is the amination of polyhydroxyl polyethers (e.g.,
polypropylene glycol ethers) by a reaction with ammonia in the
presence of Raney nickel and hydrogen (Belgian Patent No.
634,741). U.S. Patent 3,654,370 discloses the preparation of
polyoxyalkylene polyamines by reaction of the corresponding
35 polyol with ammonia and hydrogen in the presence of a nickel,
copper, chromium catalyst. The preparation of polyethers
Mo3084CIP - 5 -
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1 328526
containing amino end groups by the hydrogenation of cyano-
ethylated polyoxypropylene ethers is described in German Patent
1,193,671. Other methods for the preparation of polyoxyalkylene
(polyether) amines are described in U.S. Patents 3,155,728 and
5 3,236,895 and French Patent No, 1,551,605. French Patent No.
1,466,708, discloses the preparation of polyethers containing
secondary amino 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.
Relatively high molecular weight polyhydroxy-polyethers
suitable for the process of the present invention may be
converted into the corresponding anthranilic acid esters by
reaction with isatoic acid anhydride. German Offenlegungs-
15 schriften 2,019,432 and 2,619,840 and U.S. Patents 3,808,250;3,975,428 and 4,016,143 disclose methods for making polyethers
containing aromatic amino end groups.
Relatively high molecular weight compounds containing
amino end groups may be obtained according to German
20 Offenlegungsschrift 2,546,536 or U.S. Patent 3,865,791 by
reacting isocyanate prepolymers based on polyhydroxyl polyethers
with hydroxyl-containing enamines, aldimines or ketimines and
hydrolyzing the reaction product.
The aminopolyethers wh;ch have been obtained by the
25 hydrolysis of compounds containing isocyanate end groups are
preferred starting mater~als (German Offenlegungsschrift
2,948,419). Polyethers preferably containing two or three
hydroxyl groups are reacted (in the process disclosed in German
Offenlegungsschrift 2,948,419) with polyisocyanates to form
30 isocyanate prepolymers and the lsocyanate group is then converted
in a second step into an amino group by hydrolysis. Most
preferred are polyamines prepared by hydrolyzing an isocyanate
compound havlng an isocyanate group content of from 0.5 to 40X by
weight. The most preferred polyamines are prepared by first
35 reacting a polyether containing two to four hydroxyl groups with
an excess of an aromatic poly~socyanate to form an isocyanate
Mo3084CIP - 6 -
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1 328526
terminated prepolymer and then converting the isocyanate groups
to amino groups by hydrolysis. Processes for the production of
useful polyamines via isocyanate hydrolysis techniques are
described in U.S. Patents 4,386,218, 4,456,730, 4,472,568,
4,501,873, 4,515,923, 4,525,534, 4,540,720, 4,578,500, and
4,565,645, European Patent 0,097,299 and German Offenlegungs-
schrift 2,948,419. Similar products are also described in U.S.
Patents 4,506,039, 4,525,590, 4,532,266, 4,532,317, and in U.S.
Patents 4,723,032 issued February 2, 1988 and 4,724,252 issued
February 9, 1988. The most preferred polyamines contain from 2
to 4 amine groups and have molecular weights of from 350 to
6000.
The "amino polyethers" used (as component b)) in the
present invention are in many cases mixtures of the compounds
described above. These mixtures generally should contain (on a
statistical average) two to three isocyanate reactive end
groups.
In the process of the present invention, the "amino
polyethers" may also be used as mixtures with polyhydroxy
polyethers which are free from amino groups (such as those
exemplified in U.S. Patent 4,218,543 or even highly branched
polyetherpolyols having an average hydroxyl-functionality of
about 3 to 6 and molecular weights of about 500 to 1000),
although such mixtures are not preferred. If such mixtures are
used, however, it is necessary to ensure that at least 50
equivalent percent of the isocyanate reactive groups present in
the mixture are primary and/or secondary amino groups.
The diamines used as component c) in the process of
the present invention generally have molecular weights from
108-400 and preferably contain exclusively aromatically bound
primary or secondary (preferably primary) amino groups.
Examples of such diamines are: 1,4-diaminobenzene,
2,4-diaminotoluene, 2,4- and/or 4,4'-diaminodiphenyl methane,
3,3'-dlmethyl-4,4'-diaminodiphenyl methane,
4,4'-diaminodiphenyl-propane-(2,2), mixtures of such diamines,
and the like
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The preferred diamines have alkyl substituents in at
least one position which is ortho to the amino groups. The most
preferred diamines are those in which at least one alkyl
substituent is present in the position ortho to the first amino
5 group and two alkyl substituents are located in the position
ortho to the second amino group, each alkyl substituent having 1
to 4 carbon atoms. It is particularly preferred to use such
compounds in which an ethyl, n-propyl, isopropyl, t-butyl and/or
methylthio substituent is present in at least one position ortho
10 to the amino groups and possibly methyl substituents in other
positions ortho to the amino groups.
Specific examples of preferred amines include
2,4-diaminomesitylene, 1,3,5-triethyl-2,4-diamino-benzene,
1,3,5-triisopropyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,4-
15 diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene,
4,6-dimethyl-2-ethyl-1,3-diaminobenzene, 3,5,3',5'-tretraethyl-
4,4'-diaminodiphenyl methane, 3,5,3',5'-tetraisopropyl-4,4'-
diaminodiphenyl methane, 3,5-diethyl-3'-5'-diisopropyl-4,4-
diaminodiphenyl methane, t-butyl toluene diamine and bis-thio-
20 methyl toluene diamine. Also useful are adducts of these amines
with epoxy resins. It is also within the scope of this invention
to use aliphatic amine chain extender materials as described in
U.S. Patents 4,246,363, 4,269,945, 4,495,081 and 4,530,941,
although the aliphatic amines are not preferred.
The above-mentioned diamines may, of course, also be used
as mlxtures. It is particularly preferred to use 1-methyl-3,5-
diethyl-2,4-diaminobenzene or a mixture of this compound with
1-methyl-3,5-diethyl-2,6-diaminobenzene.
The diamine chain lengthening agent (component c)) in the
30 process of the present invent~on is preferably used in quantit~es
of from 5 to 50 wt.%, most preferably from 10 to 40 wt.% (based
on the polyether used as component b)).
Known mold release agents may be used to produce molded
articles which have excellent mold release characteristics. Such
35 internal mold release agents are among the auxiliary agents which
may advantageously be used in the process of the present
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invention. In principle, any mold release agent known in the art
may be used in the present invention but internal mold re1ease
agents such as those described, for example, in German
Offenlegungsschrift No. 1,953,637 (U.S. 3,726,952), German
5 Offenlegungsschrift 2,121,670 (British Patent 1,365,215), German
Offenlegungsschrift 35 2,431,968 (U.S. 4,098,731), German
Offenlegungsschrift 2,404,310 (U.S. 4,058,492) and U.S. Patents
4,519,965 and 4,581,386 are preferred. Preferred mold release
agents include the salts (containing at least 25 aliphatic carbon
10 atoms) of fatty acids having at least 12 aliphatic carbon atoms
and primary mono-, di- or polyamines containing two or more
carbon atoms or amines containing amide or ester groups and
having at least one primary, secondary or tertiary amino group;
esters of mono- and/or polyfunctional carboxylic acids and
15 polyfunctional alcohols containing saturated and/or unsaturated
COOH and/or OH groups and having hydroxyl or acid numbers of at
least five, ester type reaction products of ricinoleic acid and
long chained fatty acids; salts of carboxylic acids and tertiary
amines; and natural and/or synthetic oils, fats or waxes. Also
20 preferred are the zinc salts described in U.S. 4,519,965 and
4,581,386.
The oleic acid or tall oil fatty acid salts of the amine
containing amide groups which has been obtained by the reaction
of N-dimethylaminopropylamine with oleic acid or tall oil fatty
25 acid is particularly preferred.
Apart from the above-described preferred mold release
i agents, other mold release agents known in the art may in
principle be used either alone or in a mixture with the preferred
mold release agents. These add~tional mold release agents
30 include, for example, the reaction products of fatty acid esters
w~th polyisocyanates (according to German Offenlegungsschrift
2,319,648); the reactlon products of polysiloxanes containing
reactive hydrogen atoms with mono- and/or polyisocyanates
(accordlng to German Offenlegungsschrift 2,356,692 tU-S-
35 4,033,912); esters of mono- and/or polycarboxylic acids and poly-
siloxanes containing hydroxyl methyl groups (according to German
Mo3084CIP - 9 -
1 32852h
Offenlegungsschrift 2,363,452 (U.S. 4,024,090)); and salts of
polysiloxanes containing amino groups and fatty acids (according
to German Offenlegungsschrift 2,417,273 or German Offenlegungs-
schrift 2,431,968 (U.S. 4,098,731)).
If an internal mold release agent is used, it is
generally used in an amount which totals from 0.1 to 25 wt.~,
preferably 1 to 10 wt.% of the whole reaction mixture.
No catalyst is required for the reaction between
isocyanate groups and isocyanate reactive groups of the reactant
10 polyether and diamine (components b) and c)). However, catalysts
known and commonly used in the production of polyurethane foams
and microcellular elastomers are included in the group of
auxiliary agents and additives appropriate to the present
invention.
Suitable catalysts include tertiary amines such as
triethylamine, tributylamine, N-methyl-morpholine, N-ethyl-
morpholine, N-cocomorpholine, N,N,N',N'-tetramethylethylene
diamine, 1,4-diazabicyclo-(2,2,2)-octane, N-methyl-N'-dimethyl-
aminoethyl piperazine, N,N-dimethylbenzylamine, bis-(N,N-diethyl-
20 amino)-adipate, N,N-diethyl benzylamine, pentamethyl diethylene
triamine, N,N-dimethylcyclohexylamine, N,N,N',N'-tetramethyl-
1,3-butanediamine, 1,2-dimethylimidazole and 2-methylimidazole.
Organometallic catalysts may also be used in the practice
of the present invention. Particularly useful organometallic
25 catalysts include organic tin catalysts such as tin-(lI) salts of
carboxylic acids (e.g., tin-(II)-acetate, tin-(II)-laurate) and
the dialkyl tin salts of carboxylic acids (e.g., dibutyl-
tin-diacetate, dibutyltindilaurate, dibutyl-tin-maleate or
dioctyl-tin-diacetate) alone or in combination with tertiary
30 amines. Other suitable catalysts and details concerning the
action of these catalysts are given in Kunststoff Handbuch,
Volume VII, published by Vieweg and Hochtlen, Carl Hanser Verlag,
Munich 1966, e.g., on pages 96 to 102.
If a catalyst is used, quantities of about 0.001 to
35 10 wt.%, preferably 0.05 to 1 wt.% (based on component b)) are
appropriate.
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The products of the process of the present invention are
preferably molded elastomeric articles. Blowing agents may be
used to produce molded articles having a compact surface and a
cellular interior. The blowing agents used may be water and/or
5 readily volatile organic substances and/or dissolved inert gases.
Examples of suitable organic blowing agents include
acetone; ethylacetate; methanol; ethanol; halogen-substituted
alkanes such as methylene chloride, chloroform, ethylidene
chloride, vinylidene chloride, monofluorotrichloromethane,
10 chlorodifluoromethane and dichlorodifluoromethane; and butane,
hexane, heptane or diethyl ether.
Nitrogen, air and carbon dioxide are examples of suitable
inert gases.
The effect of a blowing agent may also be obtained by the
15 addition of compounds which decompose at temperatures above room
temperature to release gases, for example nitrogen. Azo
compounds such as azoisobutyric acid nitrile are examples of such
compounds. Other examples of blowing agents and details
concerning the use of blowing agents may be found in Kunststoff
; 20 Handbuch, Volume VII, published by Vieweg and Hochtlen, Carl
Hanser Verlag, Munich 1966, e.g., on pages 108 and 109, 453 to
455 and 507 to 510.
~ n accordance with the present invention, surface active
additives (emulsifiers and foam stabilizers) may also be used as
25 reaction mixture components. Suitable emulsifiers include the
sodium salts of ricinoleic sulfonates or of fatty acids or salts
of fatty acids and amines (such as oleic acid diethylamine or
l stearic acld dlethanolamine). Alkali metal or ammonium salts of
sulfonic acids (e.g. of dodecyl benzene sulfonic acid or of
30 dinapthyl methane disulfonic acid) or of fatty acids such as
rlcinolelc ac~d or polymeric fatty acids may also be used as
surface active additives.
If foam stabilizers are used, it is preferred that they
be water soluble polyether slloxanes. These compounds are
35 generally a copolymer of ethylene oxide and propylene oxide
linked to a polydimethyl siloxane group. Foam stabilizers of
this type are described in U.S. 2,764,565.
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Other auxiliary agents and additives which may optionally
be used in the process of the present invention include known
cell regulators (such as paraffins or fatty alcohols or dimethyl
polysiloxanes), known pigments, dyes and flame retarding agents
5 (e.g., tris-chloroethyl phosphate and polyphosphate) stabilizers
against aging and weathering, plasticizers, fungistatic and
bacteriostatic substances, and fillers (such as barium sulfate,
glass fibers, kieselguhr or whiting).
Other examples of suitable surface active additives and
10 foam stabilizers, flame retardants, plasticizers, dyes, fillers
and fungistatic and bacteriostatic substances and details
concerning the use of mode of action of these additives may be
found in Kunststoff Handbuch, Volume VII, published by Vieweg and
Hochtlen, Carl Hanser Verlag, Munich 1966, e.g., on pages 103 to
15 113.
When carrying out the process of the present invention,
the quantity of polyisocyanate (component a)) should preferably
be such that the isocyanate index is from 70 to 130, most prefer-
ably 90 to 110 in the reaction mixture. By "isocyanate index" is
20 meant the quotient of the number of isocyanate groups divided by
the number of isocyanate reactive groups, multiplied by 100.
When calculating the isocyanate index, any isocyanate reactive
groups possible present in the mold release agents (carboxyl
groups) are not taken into account.
The process of the present invention ls carried out by
the known reaction injection molding technique (RIM process).
Two streams are generally employed in this molding technique. In
the present invention, the polyisocyanate (component a)) is the
first reactant and the "polyamine component" (i.e., the mixture
30 of polyether component b), the diamine component c) and the
carbonate d)), is the second reactant. If any auxiliary agents
or additives are used, they are generally mixed with the "poly-
amine component". However, it may be advantageous, for example
when using a mold release agent containing lsocyanate groups, to
;-~ 35 incorporate the release agent with the reactant polyisocyanate
(component a)) before the process of the present invention is
Mo3084CIP - 12 -
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carried out. It is possible in principle to use mixing heads in
Nhich three or four separate components may be simultaneously
introduced so that no prelimlnary mixing of the individual
components is required. The quantity of reaction mixture
5 introduced into the mold ~s generally calculated to produce
molded articles having densities of from 0.8 to 1.4 g/cm3,
preferably from 0.9 to 1.2 g/cm3. When mineral fillers are used,
however, the molded articles may have densities above 1.2 g/cm3.
The articles may be removed from the mold after they have been
10 left in there from 5 to 90 seconds, preferably from 20 to 60
seconds.
The reactant mixture is generally introduced into the
mold at a starting temperature of from 10 to 60C, preferably
from 20 to 50C. The temperature o~ the mold itself is generally
15 from 40 to 100C, preferably from 50 to 70C.
The molded articles obtainable by the process of the
present invention are particularly suitable for the manufacture
of flexible automobile bumpers or car body parts. Appropriate
variation of the starting components (particularly use of a
20 relatively small proportion of diam~ne (component c)) makes it
possible, however, to obtain flexible shoe soles with good
abrasion resistance and excellent mechanical strength.
The invention is further illustrated but is not intended
to be limited by the following examples in which all parts and
25 percentages are by weight unless otherwise specified.
EXAMPLES
In the examplés, the following materials were used:
POLYETHER AMINE: prepared by hydrolyzing a prepolymer
formed from toluene diisocyanate and a 4800 molecular we~ght
30 glycerine/propylene oxide/ethylene oxide polyether (having 17~ by
weight ethylene oxide termination); the hydrolyzed product has an
amine number of 30.3.
DETDA: d~ethyl toluene diamine.
MOD-DETDA: a reaction product prepared by reacting 26
35 parts by weight of DETDA w~th 4 parts by weight of EPON*828 (a
bisglycidyl ether of Bisphenol A available from Shell).
. *trade-ma~
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1 328526
M-4050: a propylene oxide/ethylene diamine adduct having
an OH number of 630.
DB OIL: a castor oil available from Cas Chem.
Z zinc stearate.
L-5304: a silicone surfactant available from Union
Carbide.
EC: ethylene carbonate.
PC: propylene carbonate. --
A TCB: 1,2,4-trichlorobenzene.
DPE: diphenylether.
EAA: ethyl acetoacetate.
DOP: dioctyl phthalate.
ISO: the isocyanate used was a blend of (i) 20 parts by
weight of a polymethylene poly(phenylisocyanate) having an
15 isocyanate content of 32.5%, with a 19% by weight of 2,4'-isomer
content, and an isocyanate functionality of about 2.4, and (ii)
80 parts by we~ght of a 19% isocyanate content prepolymer
prepared by reacting a) 56 parts of 4,4'-methylene b~s(phenyl-
~socyanate), b) 6 parts by we~ght of a carbodiimide-group
20 mod~fied 4,4'-methylene bis(phenylisocyanate) having an NCO
content of 29.3%, and c) a 2000 molecular weight polyester diol
(based on adipic ac~d) 1,4-butane diol and ethylene glycol). The
blend had an NCO content of 21.5% by weight.
Examples 1 through 6
:j
l 25 RIM plaques were prepared using a laboratory p~ston
metering unit and clamp~ng unit. The meter~ng un~t was a two
component ~nstrument hav~ng a maximum meter~ng capacity of 0.6
l~ters. A rectangular mold, 300 mm x 200 mm x 3 mm was used to
mold the samples under the follow~ng cond~t~ons:
30 Component A temperature 40C
Component B temperature 60C
l Isocyanate ~ndex 105
;~ Mold temperature 65 C
~ M~x pressure 2646 psi
i~ 35 DemoId t~me 45 sec
.;~
3 Mo3084CIP - 14 -
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The formulations used and the physical properties were as
indicated in the following table. The samples were tested for
density (ASTM D-792) flex modulus (ASTM D-790) tensile strength
and elongation (ASTM D-638), heat sag (ASTM D-3769), notched Izod
5 (ASTM D-256), and tear strength-die "C" (ASTM D-624). Examples 1
and 4 are comparative examples.
Mo3084CIP - 15 -
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In the examples, the addition of the ethylene and
propylene carbonates resulted in sign;ficant lowering of the
viscosity of the B-side. What is particularly surprising about
the data is that excellent heat sag properties were substantially
5 maintained. One would have expected that the highly polar
carbonates would dissolve in the hard block phase causing a
significant decrease in the stiffness at elevated temperatures.
Examples 7 through 12
Using the identical technique as set forth in Examples
10 1-6, additional plaques were prepared using the formulations set
forth in Table 2. The test results were as set forth in Table 2.
i Examples 7 and 9 through 12 are comparative examples.
TABLE 2
EXAMPLE 7 8 9 10 11 12
_
15 B-S1de in PBW
Polyether Amine 65.75 62.75 62.75 62.75 62.75 62.75
DETDA 26 29 29 29 29 29
M-4050 3 3 3 3 3 3
Zn 2.5 2.5 2.5 2.5 2.5 2.5
DB Oil 2 2 2 2 2 2
L5304 0.75 0.75 0.75 0.75 0.75 0.75
PC -- 5 -_ __ __ __
TCB -- -- 5 -- -- --
DPE -- -- -- 5 -- --
25 EAA -- __ __ __ 5 __
DOP -~ ~~ ~~ ~~ ~~ 5
Flex Mod, psi 84,000 92,000 90,000 931 95,000 70,000
Tensile Strength,
30 psi 4,700 5,400 5,400 5,200 5,000 5,100
Elongation % 127 160 143 144 158 146
; Heat Sag:
(4", 325F), mm 6.5 4.5 3.7 4.7 9.0 5.7
35 (6", 250F), mm 6.3 5.5 3.7 6.8 8.2 7.7
Notched Izod:
ft-lb/in 6.7 6.7 5.9 6.2 7.5 6.1
.
~o3084ClP - 17 -
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The formulations of Examples 7 through 12 were also
tested for reactivity. 100 parts of ~leight each for~ulation were
introduced into an open can. Rotational viscosities were then
obtained from the reacting mixtures using a ccmmercially
5 available Servodyne ~evice. The data are displayed as viscosity
versus time profiles, with the point where the isocyanate is
poured into the B-s;de being zero on the time scale. The time is
then measured from this point to where the viscosity vs. time
curve becomes vertical. This point is recorded as the gel time.
10 The results obtained were as follows:
FORMULATION GEL TIME, seconds
7 3.34
8 3.56
9 3.24
3.24
11 3.16
12 3.28
As is apparent, the control, Example 7, had 26 parts of
20 DETDA, while all other formulations had 29 parts. Accordingly,
it would have been expected that all the syste~s containing the
additives would be faster reacting than the control.
Although the invention has been described in detail in
the foregoing for the purpose of illustration, it is to be
25 understood that such detail is solely for that purpose and that
var~ations can be made therein by those skilled in the art
without departing from the spir~t and scope of the invention
except as it may be limited by the claims.
*trade-mark
Mo3084CIP - 18 -
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