Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
5661
ISOCYANURATE PRODUCTS AND
POLYURETHANES THEREFPcOM
This invention relates to a method of cyclotrimerizing an or-
ganic diisocyanate to form an isocyanurate product, and to the
isocyanurate product thus formed. The invention also relates to
isocyanurate-containing polyurethanes and methods OI making ~ame.
In one aspect the invention is directed to the use of the
potassium salt of 2-pyrrolidinone as a catalyst for cyclo~rimerizing
an organic diisocyanate, to form a product containing a mixture of
monomeric and oligomeric isocyanurates.
In another aspect the invention relates to the use of the
potassium salt of 2-pyrrolidinone as a catalyst for making an iso-
, cyanurate-crosslinked polyurethane from a diol and an organic
diisocyanate, especially a non-cellular polyurethane.
The invention is also concerned with a so]ution of cyclotri-
merized organic diisocyanate in a liquid ~7inyl monomer, and to a
thermoset polymer made by treating such solution with a diol, a
peroxide catalyst and an amine or tin catalyst.
The invention is further concerned with making a urethane
prepolymer by reacting a diol with the described cyclotrimerized
organic diisocyanate product, anA with the preparation of cured
polyurethane elastomer by reaction of such prepolymer with a poly-
urethane curative.
Additionally the inven tion involves coating compositions com-
prising cyclotrimerized organic diisocyanate, a diol, and a poly-
urethane cata]yst, dissolved in an inert organic solvent.
As indicated, the invention is directed to the use of the potas-
sium salt OI 2-pyrrolidinone as a catalyst to cyclotr~merize an or-
ganic diisocyanate. The organic diisocyanate employed may be any
organic diisocyanate of the kind usually employed in the manu-
facture o polyurethanes and may be aromatic, aliphatic or cyclo-
aliphatic. Examples are toluene diisocyanate, methylene diphenyl~
isocyanate and isophorone diisocyanate. Only a small, catalytic
amount of the potassium salt of 2-pyrrolidinone is required, e . g .,
l3
--2--
from about 0.0û1% or less to about 1% or more based on the weight
of the diisocyanate. To carry out the reaction the organic diisocya-
nate and potassium salt of 2-pyrrolidinone are s~mply mixed together
and allowed to react. It is frequently more convenient to dissolve
5 the potassium salt of 2-pyrrolidinone in any suitable inert solvent
or in excess 2-pyrrolidinone. Such solution may contain for example
from about 3% or less to about 30% or more, by weight, of the
potassium salt of 2-pyrrolidinone.
The catalyst employed in the present invention has many
10 interesting features. Although the potassillm salt of 2-pyrrolidinone
has been utilized as a catalyst for the polymerization oE 2-pyrroli-
dinone to nylon-4, it has not been used as an isocyanate trimeriza-
tion catalyst, as far as the present inventor is aware. The typical
procedure utilized in the preparation of this catalyst is quite simple:
Solid potassium hydroxide is dissolved in 2-pyrrolidinone to
form a 10% by weight solution which is heated at 100C for 3 to 4
hours (until homogeneous). This catalyst is quite active as will
appear from the data below.
The cyclotrimerization may be carried out in bulk or in the
presence of an inert organic solvent. The reaction proceeds at
ambient temperatures but is faster at elevated temperatures. Some-
times the reaction is exothermic in which case it may be desirable to
cool the reaction mixture externally; in other cases it may be desir-
able to apply external heat. Depending upon the particular diiso-
cyanate and the duration of the reaction, a reaction temperature
within the range of from about 20C or less to about 150C or more
is ordinarily suitable.
The cyclotrimerization reac~ion is best carried out under an
inert atmosphere (e.g., nitrogen), whether a~ atmospheric pressure
or superatmospheric pressure.
Th~ catalyst oan be neutralized by an acylating agent, thus
quenching the cyclotr~merization reaction at any stage desired. The
activities of the acylating agents follow the pattern~ acetyl chloride
~enzoyl chloride ,~ allyl choride ~ benzyl chloride,~ methyl iodide.
Usually the reaction is allowed to proceed until insoluble mate-
rial begins ~o form, whereupon the reaction may be substantially
stopped by cooling and/or addition oE an acylating agent.
~3~31~
-3 -
Usually the reaction time ranges from about ~ hour or less to about
24 hours or more. It is desirable to agitate the reaction rnixture
especially in the initial stages.
The cyclotrimerized product is a mixture of isocyanurates,
5 containing the trimer and low molecular weight oligomers of the
trimer. The product is soluble in many common solvents such as
tetrahydrofuran, ethyl acetate, chlorinated hydrocarbons (e. g.,
chloroform, chlsrobenzene), including the common v~nyl monomers
(e.g., styrene, acrylonitrile, alkyl acrylates, etc.~.
In another aspect of the invention the potassium salt of
2-pyrrolidinone is used as a catalyst for the reaction of an organic
diisocyanate with at least one diol to form an isocyanurate-cross-
linked polyurethane. This reaction may be carried out under the
conditions previously specified or unàer conditions conven~ionally
15 used in making "one-shot" polyurethane articles. Any diol of the
kind conventionally employed in making "one-shot" polyurethanes
may be employed, including for example polyester glycols, polyether
glycols, mixed polyester-ether glycols, poly(butadiene-co-acryloni-
trile)diol, etc . Polymeric or high molecular weight diols (e . g .,
20 molecular weight of from about 200 or less to about 4000 or more)
may be employed, or monomeric low molecular weight diols (e . g .,
1,4-butanediol or cyclohexanedimethanol may be used. Mixture~; of
diols are frequently advantageous . I he diisocyanate and diol may
be employed in molar ratios conventionally used to make polyure-
25 thanes. Frequently the ratio of isocyanate groups to hydroxylgroups is from abou t 0 . 8 :1 or less to abou t 2 . 5 :1 or more . The
final products consist of isocyanurate crosslinked polyurethanes
having physical properties that render them useful for making
shaped articles of all sorts. Particularly noteworthy are non-
30 cellular products prepared in this way, as distinguished from rigidfoams based on isocyanurate structures.
Unexpectedly, the present catalys~ has been found to promote
the alcohol/isocyanate reaction at a rate faster than that of ~he
isocyanate tr~merization reaction. Thus, to demonstrate this, a
35 mixture of toluene diisocyanate and a polypropylene glycol of mole-
cular weight 425, in NCO:OH ratio of 2:1, may be allowed to react
at 80~C in the presence as well as in the abserice of potassium salt
3~
--4--
of 2-pyrrolidinone catalyst. The loss of isocyanate absorption at
2250 cm 1 and the appearance of urethane carbonyl absorption at
1720 to 1750 cm 1, and of isocyanurate ring absorption at 1420
cm, may be followed by infrared spectroscopy. The catalyst
5 promotes urethane formation at a faster rate than the appearance of
isocyanurate rings. The uncatalyzed reaction proceeds only slowly.
The catalyzed material becomes non-tacky in 15-20 minutes whereas
the uncatalyzed mixture is tacky even a~er 1. 5 hours at 80C .
This behavior is especially useful in the preparation of "one-shot"
10 po]yurethane compositions, lightly crosslinked through isocyanurate
units .
A particularly valuable form of the invention comprises a
solution o:E the oligomeric cyclotrimerized organic diisocyanate com-
position in at least one liquid vinyl monomer, that is, a liquid
15 ethylenically unsaturated (usually monoethylenically unsaturated)
polymerizable monomer such as a v~nyl aromatic compound, especially
styrene, alpha-methylstyrene, methylstyrene, 2,4-dimethylstyrene,
ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclo-
hexylstyrene, benzylstyrene and the like, substituted styrenes such
20 as chlorostyrene, 2, 5-dichlorostyrene, bromostyrene, fluorostyrene,
trifluoromethylstyrene, iodostyrene, cyanostyrene, nitrostyrene,
N,N-dimethylaminostyrene, acetoxystyrene, methyl 4-vinyl-ben20ate,
phenoxystyrene, p-vinyl diphenyl sulfide, p-vinylphenyl phenyl
oxide, vinyl naphthalene, and the like; the acrylic and substituted
25 acrylic monomers such as acrylic acid, me thacrylic acid, methyl
acrylate, methyl methacryla-te, cyclohexyl methacrylate, benzyl
methacrylate, isopropyl methacrylate, octyl methacrylate, methacrylo-
nitrile, methyl alpha-chloroacrylate, ethyl alpha-ethoxyacrylate,
methyl alpha-acetaminoacrylate, butyl acrylate, 2-ethylhexyl acry-
30 late, phenyl acrylate, phenyl methacrylate, alpha-chloroacrylonitrile,
N,N-dimethylacrylamide, N,N-dibenzylacrylam~de, N-butylacrylamide,
methacrylyl formamide, and the like; vinyl ketones, such as v~nyl
methyl ketone, vinyl ethyl ketone, v;nyl phenyl ketone, N-vinyl-
pyrrolidone, vinyl ~midazole, N-vinyl pyrrole, and the like; di~
35 methylaminoethyl methacrylate, glycidyl acrylate, dichlorobutadiene,
vinyl pyridine, and the like. Preferred materials are the vinyl aryl
monomers (especially styrene and alpha methyl styrene), the acrylic
nitriles (especially acrylonitrile and methacrylonitrile), and the alkyl
alkenoate esters (especially methyl and ethyl acrylate and metha-
crylate). Mixtur~;of vinyl aryl monomer with acrylic nitrile or alkyl
alkenoate ester are especially preferred. The amount of such vinyl
monomer in ~he composition may range from about 5% or less to
about 95% or more, based on the combined weight of the vinyl
monomer and oligomeric composition. If desired, the solution may
be stabilized by the addition of small amounts of acylating agen t
and/or free radical polymerization inhibitor. The composition may
be cured quite readily by reacting with a diol (for example a poly-
meric diol of the kind conventionally used for reaction with isocya-
nates to make polyurethanes) especially in the presence of a cata-
lyst of the kind usually used to promote polyurethane-forming
reaction between -NCO and -OH yroups, such as a tertiary amine
or tin catalyst, and a free radical polymerization catalyst such as a
peroxide catalyst. Useful cast articles of all sorts may be prepared
in this way from the described solution.
Thus, for example, the soluble nature of the oligomeric prod-
ucts in the isocyanurate mixture from toluene diisocyanate permits
ready solubilization in vinyl monomers such as styrene. At about
50% by weight, the solution viscosity is comparable to that of some
resins. The isocyanurate/vinyl mixture is found to be stable for at
least four mon ths when 1~ 2% ace tyl chloride and 0 . 03% naphtho-
quinone are added as stabilizers.
The reactive mixture ob ~ained by dissolving the isocyanurate
composition prepared from toluene diisocyanate in styrene, is cured
quite readily by polymeric diols in the presence of a tertiary amine
catalyst such as triethylene diamine or N-ethylmorpholine or tin
catalyst and a peroxide catalyst such as benzoyl peroxide. If the
peroxide catalyst is not used, a solid casting is still obtained. In
this situation, styrene then acts as a filler and the casting gradu-
ally loses weight due to the vola~ility of styrene. Peroxide catalyst
polymerizes ~e styrene. The casting then does not lose weight
when kept at room temperature or heated to 100C. Good physical
properties are obtained after a room temperature cure Eor 1 week
and no post curing at higher temperatures is necessary. These
products can be classified as ~mpact resistant styrene polymers and
3~ 1
--6--
~s such they have properties close to ABS polymers, w~th the
added advantage of processibility from the liquid state, requiring
less costly processing machines.
In the form of the invention wherein the oligomeric isocyan-
5 urate preparation is used to make a polyurethane prepolymer, it w~llbe understood that the oligomeric cyclotrimerized product is reacted
wi th any diol of the kind conventionally employed in making poly-
urethane propolymers (such as a diol of the kind described above),
suitably in the absence of moisture. Subsequently, the resulting
10 prepolymer may be mixed with additional diol and a polyurethane
curative ~e.g., a diamine or the like), with or without a polyure-
thane catalyst (e . g . a tertiary amine or a tin catalyst) to form a
cured polyurethane elastomer or plastic of ~he desired shape.
An excess of the organic diisocyanate may also be used as a
15 solvent for the cyclotrimeri2ed oligomeric product. Thus, the
isocyanurate mixture obtained from toluene diisocyanate is soluble in
monomeric toluene diisocyanate. The solution of oligomer in diiso-
cyanate may be used to prepare a prepolymer (by reaction with a
diol as in conventional polyurethane prepolymer practice) and cured
20 elastomers and plastics may then be prepared from these prepoly-
mers in the usual manner. For example, various amounts of the
isocyanurate mixture obtained from toluene diisocyanate were dis-
solved in toluene diisocyanate and these mixtures used to prepare
prepolymers. Cured elastomers were prepared in the usual manner.
25 The isocyanurate units did not substantially alter the physical
properties of unmodified elastomers, when present at lower concen~
trations . Changes were more noticeable in percent elonga tion and
tear strength than in other proper~ies, showing that the isocy-
anurate units impart more rigidity ~o the polyurethane elastomers
30 and plastics.
The product obtained from TDI (toluene diisocyanate) by the
action oE ~he potassium salt of 2-pyrrolidinone appears to be a
complex mixture of various isocyanurate materials. The composition
depends upon whether TDI is trimerized in bulk or in solution.
35 The best way to analyze the mixture is to separate each component
quantitatively. However, for commercial applications of the above
mixtures, it is not necessary to know the composition exactly, as
~3~7
--7--
long as the amine equivalent is known. Based on this information,
one equivalent amount of curative can be employed to react w~th the
composition .
An empirical estimate of the amount of various components
5 present in the above mixture can be made based on certain assump-
tions and a very simple fractionation experiment. Thus, 100 g of
the isocyanurate mixture (amine equivalent 160) is dissolved in 250
ml of ethyl acetate and the solution is poured slowly into excess
n-hexane with vigorous stirring. The precipitated material is fil-
10 tered and freed o~ solvent by drying in a vacuum oven at 80~C/6hours. The residue weighs 82 g (amine equivalent 206). The
following equation describes the different products. From infra-red
spectra it is established that only isocyanurate and isocyanate
structures are present and neither carbodiimide nor diazetanedione
15 structures can be found.
CH3
NCO / CO NCO NCO ~ NCO NCO NCO NCO
catalys ~ + ~ + ~ ~
NCO NCO NCO NCO NCO NCO NCO
TDI Unreacted TDI TDI-trimer TDI-pentamer* TDI-heptamer*
Isocyanate groups 2 3 4 5
No.of TDI units 1 3 5 7
Molecular weight174 522 870 1218
OCN NCO ,NCO ~ NCO
OCN ~ O ~ ~ et~
TDI-nonamer*
Isocyanate groups 6 * isocyanurate oligomers
No~of TDI units 9
Molecular weight1566 ~
~ = lsocyanurate ring.
It is difficult to estimate the exact amount and nature of each
oligomer present but it is apparent that these oligomers are of low
molecular weight since they are soluble in common solvents. The
~32~
following calculatiorls may be made wi~h respect to a product in
which the average number of isocyanate groups in the oligomer is 5
and the average molecular weight is 1218, based on the TDI-hepta-
mer. If 100 g of the original mixture has x moles of unreacted
TDI, y moles of TDI-trimer and z moles of TDI-oligomer, then
522Y ~ 1218Z = 206 orY = 188 z
3Y + 5Z 96
Because 522Y ~ 1218Z - 82,Z(522 x 188 + 1218) = 8Z
Therefore Y = .072 mole = 38 g.
Z = .037 mole = 44 g.
Thus, in such a product, 100 g of the mixture has 18 g of
unreacted TDI, 38 g of TDI trimer and 44 g TDI-oligomer. Thus a
considerable amount of oligomer is present in such a m~xture.
The following examples will serve to illustrate the practice of
the inven~ion in more detail.
Example 1
One kilogram commercial TDI (a mixture of 80% 2,4-isomer and
20% 2,6-isomer of toluene diisocyanate) is placed in a two liter
container which is equipped with a mechanical stirrer and a thermo-
meter. The contents are kept under a nitrogen atrnosphere and a
catalyst solution prepared from 200 mg potassium hydroxide in 2 g
2-pyrrolidinone (this catalyst preparation is hereinafter referred to
as "K2P" ) is added with thorough mixing . Ten to fifteen minutes
after the addition, an exothermic reaction starts. The temperature
of the reaction mixture is kept below 70C by cooling with a water
bath. The reaction mixture becomes increasingly viscous. As the
mixtwre begins to solidify, the stirrer and the thermometer are
removed. The container is sealed under nitrogen and the reaction
allowed to continue to completion overnight. The amine equivalent
of the product ranges from 150 to 165, showing that most of TDI
has undergone trimerization. The product is soluble in tetrahydro-
furan, chloroform, ethyl acetate, excess TDI and common vinyl
monomers. The infra-red spectrum shows the presence of isocyan-
urate rings w~th strong absorp~ons at 2250 cm~l (-NCO), 1720 cm 1
(carbonyl) ~nd 1420 cm 1 (isocyanura~e).
- 9-
Example 2
In a 500 ml, round bottom, three-necked flask equipped with a
magnetic stirrer and a thermometer is placed a mixture of 50 g TDI
and 50 ml purified chlorobenzene. The contents of flask are kept
5 under nitrogen and 50 mg of the catalyst solution of potassium salt
of 2-pyrrolidinone in 2-pyrrolidinone (K2P catalyst so]ution prepared
as in Example 1) added. The reac~ion mixture is heated at 60-70C
for three hours during which time the solution becomes viscous.
The solution is cooled to room temperature and poured into 300 ml
10 diethyl ether with vigorous stirring. The solid material obtained is
filtered under suction and washed several times with ether, then
dried free of residual ether and chlorobenzene at 80C/vacuum for 6
hours to a constant weight. Yield 43 g (86%). Amine equivalent,
255. Theoretical amine equivalent for the trimer, 174.
15 Example 3
In a 500 ml, round bottom, ~hree-necked flask, fitted with a
magnetic stirrer and a thermometer is placed a mixture of 60 g
methylene diphenylisocyanate (MDI) and 100 ml purified chloroben-
zene. The mixture is kept under nitrogen and 20 mg of K2P cata-
20 lyst mixture (prepared an in Example 1) is added. Insoluble mater-
ial starts to form after the reaction mixture has been heated at
80-~5 for 45 minutes. The mixture is then quickly cooled to room
temperature and the contents of the flask poured in~o 300 ml diethyl
ether with vigorous stirring. The solid material obtained is filtered
25 under suction and washed several times with ether, and freed of
- solvents by drying at 80C/6 hours in a vacuum oven. Yield 20 g
(33%). Amine equivalent, 330. Theoretical amine equivalent for the
trimer, 250. The product is soluble in common solvents such as
tetrahydrofuran and chloroform. The infra-red spec~rum shows the
30 presence of isocyanurate groups.
Example 4
One hundred g isophorone diisocyanate is tr~merized at 110C
for 18 hours using 50 mg of the K2P catalyst mixture. A ~Tlassy
solid is obtained with an amine equivalent of 200. Theoretical amine
35 equivalent for the trimer, 222. The infra-red spectrum shows the
presence of the isocyanurate ring struc~ure.
~L3~ r~
-10-
Example 5
In a 500 ml, round bottom flask equipped with a magnetic
stirrer, a thermometer and a nitrogen inlet tube is placed a mixture
of 34.8 g TDI (0.2 mole), 11.9 g phenylisocyanate (0.10 mole~ and
5 50 ml purified chlorobenzene. The mixture is kept under nitrogen
and 30 mg of the K2P catalyst mixture added with vigorous stir-
ring. The mixture is heated at 60-70C for three hours. The
solution is cooled to room temperature, then poured into 300 ml
diethyl ether with vigorous stirring. The solid material obtained is
10 filtered, washed several times with ether and dried until free of
solvents at 80C/6 hours in a vacuum oven. The material is sub-
stantially difunctional~ Yield 45 g (95%). Amine equivalent, 450.
Exam~le 6
In a 500 ml resin ket~le, fitted with a stirrer, a thermometer
and nitrogen inlet, 20 g (0.022 mole) of isocyanurate material from
, Example 5 is dissolvecl in 100 ml purified dimethyl sulfoxide. Two g1,4-butanediol (0.022 mole) is added and the mixture heated to 90C
and stirred for three hours. The progress of the reaction is
followed by the disappearance of the isocyanate absorption at 2250
20 cm 1 in infra-red spectrum. When all the isocyanate group has
reacted, there is no siyn of gelation. The polymer thus prepared
is precipitatPd by pouring the solution in~o 1000 ml water. The
solid is filtered under suction, washed several times with water and
dried in a vacuum oven at 100C to constan~ weight. Yield 18 g
25 (81%). The fact that the product is a linear polyurethane indicates
that the isocyanurate material obtained in Example 5 is substantially
a difunctional material.
Example 7
This Example shows that the isocyanurate m~xture from TDI
30 consists of some unreacted TDI, monomeric isocyanura~e and oligo-
meric isocyanurate. Isocyanurate mixture (100 g), prepared as in
~xample 1, is dissolved in 250 ml ethyl acetate . The solu ~ion is
poured into 10 times its volume of n-hexane with vigorous s ~irring
and the precipitated rnaterial is fil~ered and dried. Weight re-
35 covered 82 g. Amine equivalent, 206. The theoretical amine
31Y,~3~
equivalent of monomeric isocyanurate is ï74. Thus higher molecularweight oligomeric isocyanurates must be present in this m~xture
which has an am~ne equivalent of 206. Each of the solution-
prepared isocyanurates, precipitated as described in Ex~nples 2, 3,
5 and 5, has an amine equiva~ent higher ~an that expected for the
monomeric trimer struc~ures. This indicates tha~ soluble oli~omeric
isocyanurates are obtained by the action of the present catalyst
system.
Example 8
~larious diols indicated in TABLE I are reacted with TDI in the
presence of the K2P catalyst system to make one-shot polyurethanes.
Thus, in a one liter container 38 g of polypropylene glycol (about
0.09 mole) is mixed with 100 mg of the K2P catalyst. The m~xture
is warmed to 60C and evacuated to remove dissolved air bubbles.
After half an hour, 21 g TDI (about 0.12 mole) [NCO:OH, 1.3:1.0]
is added, mixed well and further evacuated to remove bubbles.
The mixture is then poured onto a flat glass plate mold and kept at
room temperature for 15 minutes, followed by post-curing at 100C/2
hours. A clear casting is obtained. TABLE I summarizes the
physical properties of various compositions made in this way using
polypropylene glycols (PPG) of molecular weights 425~ 710 and 1010,
poly(tetramethylene ether glycol) (PTMG) of 1000 molecular weight,
N,N'-bis(2-hydroxypropyl)aniline (BHPA), and 1,4-butanediol, in
the molar proportions shown. The physical properties are measured
by the following ASTM procedures: tensile properties, D-638-63T;
~ear strength D-624-54; hardness, D-1484-59.
TABLE I
Properties of Isocyanurate Crosslinked Polyurethanes
Prepared by 'One~Shot' Method, Using K2P Catalyst
Tear
Molar ratios Tensile % Elon- Strength
of the com- Strength gation at (Die G) Hardness
Composition ponents Psi break Pli Shore A
PPG-425+TDI 1. 0 :1. 3 2140 200 380 62
PPG-425+TDI 1. 0 :1. 4 2600 200 460 72
PPG-710+TDI 1. 0 :1. 5 430 150 120 48
3Q~
-12-
TABLE 1 Cont'd.
Tear
Molar ratios Tensile % Elon- Strength
of the com- Strength gation at (Die C) Hardness
Com~osi~ion ponents Psi break Pli Shore A
PPG-710+TDI 1.0:1.6 720 150 110 61
PPG-710+TDI 1.0:2.0 1200 150 150 77
PPG-1010~TDI 1.0:2.0 400 150 90 45
PTMG-1000+
BHPAtTDI 1.0:1.0:3.0 2500 100 280 83
PTMG-1000~
BHPA+TDI 1. 0: 2 . 0: 4 . 54400 100 770 85
PTMG-1000+
1, 4-butanediol
+T:DI 1 . 0: 2 . 0: 4 . 5 6800 50 - - - - -
PPG-1010+
BHPA+TDI 1. 0: 2 . 0: 4 . 54400 50 --- --
Example 9
In a three-liter resin kettle fitted with a stirrer, a thermo-
20 meter and a nitrogen inlet tube is placed 1, 500 g TDI . Whilestirring under nitrogen, 3 . 3 g K2P catalyst mixture is rapidly
added. An exothermic reaction starts in a few minutes. After 30
minutes, the temperature reaches 65C and the reaction mixture is
cooled using a water bath. At this stage the reaction mixture is
25 quite viscous and 250 ml styrene is added to reduce viscosity. A
total of 1500 ml (1350 g) styrene is added in 250 ml portions at
suitable intervals so that a workable viscosity is always maintained.
In three hours, the temperature has fallen to 38C. To stabilize
the mixture, 750 mg naphthoquinone and 5.8 g acetyl chloride are
30 added and mixed thoroughly. Amine equivalent is 306.
Example 10
Using the same method as described in Example 9, various
mixtures are prepared by replacing styrene with equivalent amounts
of other v;inyl monomers such as acrylonitrile, methyl acrylate,
35 ethyl acrylate and n-butyl acrylate.
-13-
ExamE~le_
The above mixtures from Examples 9 and 10 are compatibl~
with polyethylene glycols and polypropylene glycols of various
molecular weights. They are also compatible with poly(butadiene-
5 co-acrylonitrile)diol, cyclohexanedimethanol, etc. The curing of
these compositions is accomplished as shown below.
The composition (67 g) from Example 9 is mixed with 40 g
polyethylene glycol 400 [NCO:OH, 1.1:1.0]. A clear solution is
obtained. Benzoyl peroxide paste (50%, 1 g) is added and n~ixed
10 thoroughly. The mixture is quite stable. However, when 0.25 ml
N-ethylmorpholine is added and mixed, an exothermic reac~ion
starts. The resin m~xture is poured onto a glass mold and allowed
to set. Gel time is 15 to 20 minutes. The casting is removed from
the mold after 3 hours. The physical properties are determined
15 a~ter allowing the casting to cure at room temperature for 7 days.
TP.BLE II summarizes the physical properties of the casting
obtained from the compositions indicated. ~lexural properties are
obtained according to ASTM D-790-66; heat deflection by ASTM
D-648-56 and Izod notched impact strength by ASTM D-256-70.
~ 3,6~
U ~ ,~ 1 n N
s~ E3 a~ o N ,~ N d'' 0 ~1 ~ O ~I c~
~ ~ ~P;
.,_,
._ ~o ,o o --
~ ~ , ~ O~ OI
a~ ~ 3
E~
F~
~-~Q
~ O .~ ~ ~ O .-1 N ~ ~- O ~
E-~ ~ ~ r8 ~4 ~ ~ N N O N ~i 1 ~i 0
;~ L ~ o\l
a~ ~ ~ L~U~O 000 ~D~O
o ~ 3 N ~r ~_ ~ N ,.~
U~ S~
fio ~ ~ o~o o~
~ O ~, U~ oo~ ~-~r.-- ~rcoco
~ ~ ~1~ ~ ~ ~
~1 cc~o ~ s~ o ~oo
Q ~
V ~ Q, ~ .n ~ ~ 0 o C: O :~
U~ o U~ o U~
3~7
--15--
g
~, E~ a a N~
~3 ~ L
~ ~ ~UE~ ~
C~ ~r' I $
~, a O~o
O
a x
C) ~ ~:1 ~
~c ;e~ ~ a x l ~ ' 'r ~ e
~ :~ a o\ h ,~ ~
.~ i~ ~DO
O ~
;~ ~ ~ ~O
o o E~ 4 P~ o ~ o\ ,~,
3~ , e_
O ~ O ~n O
~ ~ ~ c~ .E; X ~ o ~ z u~
~ o u~ O In
-16-
Exanlple 12
In this Example, instead of a single monomer, mixtures of
monomers are used (styrene: ethyl acrylate in 1:1 ratio by volume,
and styrene:n-butyl methacrylate in 1:1 ratio by volume) to
5 prepare isocyanurate resins following the procedure of Example 9
~isocyanurate 52%, vinyl monomers 48%, by weight). The resins are
employed to make castings accordiny to the procedure of Example
11, using polyethylene glycol (PEG) of molecular weight 400 or 600,
at an NCO:OH ratio of 1.1:1.0, in the presence of 1% by weight of
10 benzoyl peroxide paste and 0 . 25% by volume of N-ethyLmorpholine
catalyst. After cure at room temperature for seven days the
physical properties are as shown in TABLE III.
T A B L E III
Properties of Castings Prepared from Isocyanurate Resins
Containing Mixtures of Vinyl Monomers
Tensile Properties ear Properties Hardrless
Tensile Elonga-
Strength tion
Composition (Psi) (%)_ Die C (Pli) Shore A
Isocyanurate
+ lethylacrylate:
styrene]
PEG 400 2000 130 360 80
PEG 600 1000 200 90 60
Isocyanurate
+ ¦n-butyl
~ethacrylate:
styrene]
PEG 400 2020 100 440 80
3GPEG 600 2280 260 130 70
TABLES II and III show that the final products have a higher
elongation when they are prepared from a mixture o:E styrene and
an acrylate monomer, rather than from a single monomer. Other
physical properties show less significant variations. In these
35 systems, the vinyl monomers undergo polymerization during cure of
~3
-17~
the resins. The above results indicate that ~he contributions of
homopolymers and of copolymers to properties such as elongation
are different.
Example 13
In this example, styrenated isocyanurate resin prepared as in
Example 9 is blended with two diols, namely, polyethylene glycol
(PE~a) of 600 molecular weight and 1, 4-butanediol, in the ratios
indicated in TABLE IV, and castings are made using benzoyl perox-
ide and M-ethylmorpholine as in Example 11. Physical properties
after cure at room temperature for seven days are shown in TABLE
IV .
T A B L E IV
Properties of Produc~s from S~yrenated Isocyanurate
Resins Cured with a Mixture of Diols
Tensile Properties ~ Flexural Modulus
~ensile Elonga-
Strength tion
Composition (Psi) (%) Die C(Pli) (K Psi)
Resin: PEG
600: 1,4-
Butanediol
(ratio in
equivalents)
4:3:1 4100 150 650 30
! 25 3:2:1 3800 100 830 50
2:1:1 4100 125 840 60
3:1:2 5200 30 570 160
~:1:3 5000 5 230 180
Resin: PEG
600: 1,4 - Buta-
nediol (ratio
in equivalents)
4:3:1 3900 175 600 30
3:2:1 4000 100 970 50
2:1:1 6100 75 ~90 ---
3:1:2 4700 10 390 190
-18-
Thus, products with medium to hiyh flexural moduli with good
elongation characteristics can be prepared readily by choice of a
suitable mixture of diols instead of a single diol.
Example 14
IJrethane prepolymer resin based on a polyether diol is pre-
pared as follows:
Poly(tetramethylene ether glycol) of 1000 molecular weight (750
g) is maintained under a nitrogen atmosphere in a 1-liter resin
kettle equipped with a mechanical stirrer, thermometer and nitrogen
inlet, heated to 95C, then placed under vacuum for 1 hour to
remove traces of moisture. The diol is then cooled to 40C, TDI
~268 g), (NCO:OH, 2.05:1.0) is quickly added and the mixture
maintained at 80C Eor 1 hour after the initial exotherm is over.
The prepolymer ~hus obtained is degassed under vacuum for 15
minutes with stirring and 15 minutes without stirring and stored in
a metal can after being sealed under nitrogen. Amine equivalent,
645 .
Differen~ weight percentages of isocyanurate products from
TDI (indicated as "ICU A" in Table V) or isocyanurate products
from a mixture of 2 moles TDI and 1 mole phenyl isocyanate (indi-
cated as "ICU B" in Table V) are dissolved in TDI and the appro-
priate isocyanate values determined. Prepolymers are prepared
following the procedure in the previous paragraph using these
isocyanate mixtures and keeping NCO:OH at 2.05:1Ø
Example lS
The urethane prepolymer resin prepared as in Example 14 (100
g) is heated in a vacuum oven at 80C and evacuated for 1 hour
until all the dissolved gases are removed . Methylene bis (o~chloro-
aniline) (18.5 g) (NCO:NH2 1.1:1.0) is melted and mixed with the
degassed prepolymer. The mixture is fur~er degassed and then
poured on~o a flat mold and cured at 100C~16 hours to form an
elastorner. The isocyanurate-containing prepolymers of Example 14
are similarly cured with methylene bis~o-chloroaniline) to form elas-
tomers keeping N~:O:NH2 at 1.1:1Ø TABLE V summarizes physical
properties of these castings.
3~
--19--
V c~oo ~D
: , o ~co~* ~:n*
U~ ~
V
o
o ooooo
t- ~oo ~o~ 0
o o
o
U~ ,~q
~ , 13 oo8oo '
U~
~ ~ q~ ~ ~>
E~ ~ 0^ - ~ o o o o o O a
~ u~ a P~ D ~D ~ ~ ;J
raO ~0
a~ ~ ,0,
h O o\O ~l)
U~ h t~ 0
~\\~\\ a~ u ~
~ ~ ~ .U~ .~
:~ ~ ' ~ ~ m
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c~ 3 u~ V V t~ V V *
In O U~
-20-
Example 16
In a 500 1l-1, round bottom, three-necked flask, fitted with a
magnetic stirrer, reflux condenser, thermometer and ni~rogen inlet
tube, 52 g solid isocyanurate mixture prepared from toluene diiso-
5 cyanate using K2P catalyst is dissolved in 100 ~nl ethyl acetate w~thstirring under nitrogen. The mixture is warmed to 60C, then a
mixture of poly(tetramethylene ether glycol) 1000 molecular weight
~63 g~ and di-n-butylamine (16 g) dissolved in ethyl acetate (50 ml)
is added to the above solution duriny 5 ~o lO minutes. The mixture
10 is heated at 6û-70C for 30 minutes and the contents of the flask
coated onto a flat glass plate. The solvent is allowed to evaporate
and the coating cured by moisture in the atmosphere. After two
days, most of the solvent has evaporated and the coating is post-
cured at 100C/2 hours. TABLE VI lists some of the physical
15 properties of such coatings.
TABLE VI
Physical Properties of Moisture-cured, Solvent-cast
Isooyanurate Polymer Coatings
Tear
Ratio Tensile Elonga- Strength
NCO/Active Strength tion Die C,
C:omposition Solvent hydrogen Psi _ % Pli
Isocyanurate+ Ethyl 1. 7 :1. 0 1600 300 260
PTMG 1000+ acetate
25 di-n-butyl-
am~ne
Isocyanurate+ Chloroform 1. 7 :1. 0 2400 250 330
PTMG 1000+
di-n-butyl-
30 amine
Isocyanurate+ Chloroform 1. 6 :1. 0 2300 200 360
PTMG lOOOt
n-bu~anol
